JP6656114B2 - Abnormality diagnosis device for blow-by gas reduction device - Google Patents

Description

  The present invention relates to a blow-by gas reducing device that flows blow-by gas generated in an engine through an intake passage and returns the blow-by gas to the engine, and more particularly to an abnormality diagnostic device configured to diagnose an abnormality of the reducing device.

  Conventionally, as this type of technology, for example, an abnormality diagnosis device for a blow-by gas reduction device described in Patent Literature 1 below is known. This blow-by gas reduction device (Blowby Gas Ventilation device: hereinafter referred to as “BGV device”) includes a PCV passage (blow-by gas reduction passage) for introducing blow-by gas into an intake passage downstream of a throttle valve, and a blow-by gas reduction passage. A PCV valve for adjusting the flow rate of the blow-by gas. The abnormality diagnosis device is configured to diagnose whether an abnormality has occurred in at least one of the PCV passage and the PCV valve. That is, during the ISC control (when controlling the idling rotational speed to the target value), the abnormality diagnosis device operates the PCV valve when the amount of intake air taken into the engine is a predetermined amount and no abnormality occurs in the BGV device. An engine operating condition in which the opening is maintained at a predetermined first opening is referred to as a first operating condition, and an engine operation in which the opening of the PCV valve is maintained at a second opening different from the first opening. The condition is a second operation condition. In the ISC control, the abnormality diagnosis device controls the control amount of the throttle valve when the actual operating condition is in the first operating condition, and controls the throttle valve when the actual operating condition is in the second operating condition. When the difference from the amount is equal to or less than the reference value, it is determined that an abnormality has occurred in the blow-by gas returning device.

JP 2009-197676 A

  However, in the abnormality diagnosis device described in Patent Document 1, the opening degree of the PCV valve is changed between the first opening degree and the second opening degree during the ISC control, and based on the correction value of the intake air amount by the throttle valve at that time. The abnormality of the BGV device is determined. Here, in order to control the idling rotation speed to the target value, the opening of the PCV valve cannot be changed so much in the first place, the change in the flow rate of the blow-by gas is small, and the range of the abnormality determination is limited. Had become. For this reason, it was not possible to secure a change in the flow rate necessary for determining whether or not a hole was large or small in the pipe of the PCV passage. In addition, in order to ensure the accuracy of the abnormality determination, it is necessary to take a certain amount of time for the determination.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a blow-by gas reduction device abnormality diagnosis device that can accurately diagnose a perforated abnormality in a blow-by gas reduction device. It is in.

In order to achieve the above object, an invention according to claim 1 is an abnormality diagnosis device for diagnosing an abnormality of a blow-by gas reduction device for flowing blow-by gas generated in an engine to an intake passage and returning the blow-by gas to the engine. Is configured to generate a driving force in response to the supply of fuel and to shut off the supply of fuel during deceleration.The blow-by gas reducing device includes a blow-by gas storage unit for storing blow-by gas generated by the engine. , An intake amount control valve provided in the intake passage to adjust the amount of intake air flowing through the intake passage, and blow-by gas stored in the blow-by gas storage section flowing through the intake passage downstream of the intake amount control valve to be returned to the engine. a blowby gas returning passage for, configured with variable opening to adjust a blow-by gas flow rate in the blow-by gas returning passage electric And a gas flow rate control means, the abnormality diagnostic device includes an intake quantity detecting means for detecting an intake air amount upstream of the intake passage from the intake flow control valve, anomaly for diagnosing an abnormality of the blow-by gas returning device Diagnostic means, wherein the abnormality diagnosing means sets the gas flow rate adjusting means to a first opening and a larger opening than the first opening when the engine is decelerated and when the supply of fuel to the engine is cut off. The first opening is controlled by the second opening and the first opening is detected by the intake amount detecting means when the first opening is controlled, and the first intake is detected by the intake amount detecting means when the opening is controlled to the second opening. The purpose of the present invention is to diagnose an abnormality of the blow-by gas returning device based on the obtained second intake air amount.

  According to the configuration of the present invention, when the engine is decelerated and when the supply of fuel to the engine is cut off (during deceleration fuel cut), the abnormality of the blow-by gas reducing device is diagnosed. Here, during the deceleration fuel cut, no torque is generated in the engine, and the intake air amount adjustment valve is closed, and the intake air passing through the valve is constant in the sonic state. Therefore, the difference between the first intake air amount detected when the gas flow rate adjusting means is controlled to the first opening degree and the second intake air amount detected when the gas flow rate adjusting means is controlled to the second opening degree is compared. It is possible to achieve a large target. In the sonic state of the intake air, even if the opening degree of the gas flow rate adjusting means is changed, the intake air quantity passing through the intake air quantity adjusting valve does not change, and the opening degree change of the gas flow rate adjusting means directly changes the intake air quantity. That is, the difference between the first intake air amount and the second intake air amount becomes relatively large.

  To achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the abnormality diagnosing means compares the first intake air amount with a first predetermined value to determine a second intake air amount. The amount is compared with a second predetermined value that is larger than the first predetermined value, and the abnormality of the blow-by gas reducing device is diagnosed based on the comparison result.

  According to the configuration of the present invention, in addition to the operation of the invention described in claim 1, each of the first intake amount and the second intake amount is individually compared with the first predetermined value and the second predetermined value. Therefore, the change in the intake air amount is properly confirmed.

  In order to achieve the above object, according to a third aspect of the present invention, in the first aspect of the present invention, the abnormality diagnosing means further controls the gas flow rate adjusting means to an opening degree of zero, and the first intake air amount The difference between the zero intake air amount detected by the intake air amount detection means when the opening degree is controlled to zero is calculated as the first intake air amount increase, and the difference between the second intake air amount and the zero air intake amount is calculated as the first intake air amount. 2, the first intake increase is compared with a third predetermined value, the second intake increase is compared with a fourth predetermined value larger than the third predetermined value, and based on the comparison results, The purpose is to diagnose an abnormality of the blow-by gas returning device.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 1, the difference between the first intake air amount and the second intake air amount and the reference zero intake air amount is respectively equal to the first intake air amount. It is calculated as the increase and the second intake increase. Therefore, in the first intake increase and the second intake increase, the influence of the individual difference of the intake amount detecting means and the like is reduced. Further, since each of the first intake increase and the second intake increase is individually compared with the third predetermined value and the fourth predetermined value, a change in the intake increase is properly confirmed.

  In order to achieve the above object, according to a fourth aspect of the present invention, in the second aspect of the present invention, the abnormality diagnosing means determines that the first intake air amount is larger than a first predetermined value and the second intake air amount is larger than a second predetermined amount. When the intake air amount is larger than the second predetermined value and the change from the first intake air amount to the second intake air amount is a linear change, it is determined that the blow-by gas reducing device is normal, Is less than or equal to a first predetermined value, the second intake amount is less than or equal to a second predetermined value, and the change from the first intake amount to the second intake amount is a linear change. In this case, the purpose is to determine that the blow-by gas return passage has a perforated abnormality.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 2, it is possible to easily determine whether there is a hole abnormality in the blow-by gas return passage under the above conditions.

  In order to achieve the above object, according to a fifth aspect of the present invention, in the fourth aspect of the invention, the abnormality diagnosing means determines that the second intake air amount is equal to or less than a second predetermined value, and When the change from the intake air amount to the second intake air amount is a curved change, it is intended to determine that the blow-by gas return passage is clogged and abnormal.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 4, the clogging abnormality of the blow-by gas return passage is easily determined based on the above conditions.

  In order to achieve the above object, according to a sixth aspect of the present invention, in the third aspect of the invention, the abnormality diagnosing means determines that the first intake air increase is greater than a third predetermined value and If the intake air increase is greater than the fourth predetermined value and the change from the first intake air increase to the second intake air increase is a linear change, it is determined that the blow-by gas reduction device is normal, Is less than or equal to a third predetermined value, the second increase in intake is less than or equal to a fourth predetermined value, and the change from the first increase in intake to the second increase in intake is a linear change. In this case, the purpose is to determine that the blow-by gas return passage has a perforated abnormality.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 3, an abnormality in perforation of the blow-by gas return passage can be easily determined based on the above conditions.

  In order to achieve the above object, according to a seventh aspect of the present invention, in the sixth aspect of the invention, the abnormality diagnosing means determines that the second intake air amount becomes equal to or less than a fourth predetermined value, and When the change from the increased intake air amount to the second increased intake air amount is a curved change, it is intended to determine that the blow-by gas return passage is clogged and abnormal.

  According to the configuration of the present invention, in addition to the function of the invention described in claim 6, it is possible to easily determine whether the blow-by gas return passage is clogged abnormally based on the above conditions.

  In order to achieve the above object, according to the invention described in claim 8, in the invention described in any one of claims 1 to 7, the abnormality diagnosis device includes an air-fuel ratio calculation unit for calculating an air-fuel ratio in the engine. Further, the abnormality diagnosis means includes an abnormality diagnosis based on a difference between the air-fuel ratio calculated by the air-fuel ratio calculation means and a reference value, based on the deviation of the air-fuel ratio from the reference value, together with the abnormality diagnosis based on the intake air amount detected by the intake air amount detection means. The purpose is to diagnose.

  According to the configuration of the present invention, in addition to the operation of the invention according to any one of claims 1 to 7, in addition to the abnormality diagnosis based on the intake air amount, the abnormality of the blow-by gas reduction device is diagnosed based on the deviation of the air-fuel ratio. Is performed, the abnormality diagnosis becomes more reliable.

  In order to achieve the above object, according to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the gas flow rate adjusting means has a variable opening degree directly attached to a pipe of an intake passage. It is intended to be an electric PCV valve.

  According to the configuration of the present invention, in addition to the effect of the invention according to any one of claims 1 to 8, the PCV valve is directly attached to the intake passage, so that there is no piping between the intake passage and the PCV valve, Diagnosis points for perforated abnormalities are omitted by the amount of the piping.

In order to achieve the above object, according to a tenth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the blow-by gas reduction device includes a first end and a second end, a first passage in which the first end to the part communicates, comprises a first end and a second end, a second passage in which the second end communicates with the intake passage downstream of the intake flow control valve, a first end A third passage including a second end for introducing fresh air from the first end, between a second end of the first passage, a first end of the second passage, and a second end of the third passage; A three-way switching valve, which is provided to selectively connect the first end of the second passage to the second end of the first passage or the second end of the third passage, and a second passage. An electric PCV valve configured to be variable in opening to adjust the flow rate of gas flowing through the valve, and control means for controlling the three-way switching valve and the PCV valve. The control means controls the three-way switching valve and the PCV valve according to the operating state of the engine to selectively flow blow-by gas or fresh air to the intake passage downstream of the intake air amount adjusting valve according to the operating state of the engine. The first passage and the second passage constitute a blow-by gas returning passage, and the three-way switching valve and the PCV valve constitute gas flow regulating means.

  According to the configuration of the above invention, in addition to the operation of the invention according to any one of claims 1 to 8, the three-way switching valve is controlled according to the operating state of the engine, so that the first end of the second passage is formed. Is selectively communicated with the second end of the first passage or the second end of the third passage, and blow-by gas or fresh air is selectively flown into the intake passage downstream of the intake air amount adjustment valve. Accordingly, the introduction of blow-by gas and fresh air into the intake passage can be selectively switched only by controlling one relatively responsive three-way switching valve. Further, in the blow-by gas returning device, abnormality of at least one of the first to third passages, the three-way switching valve, and the PCV valve is diagnosed.

  To achieve the above object, according to an eleventh aspect of the present invention, in the tenth aspect of the present invention, the control means causes the fresh air to flow into the intake passage when the abnormality of the blow-by gas reducing device is diagnosed. For this purpose, the purpose is to control the three-way switching valve so that the first end of the second passage communicates with the second end of the third passage.

  According to the configuration of the present invention, in addition to the operation of the invention described in claim 10, the blow-by gas returning device diagnoses an abnormality in the first passage, the third passage, the three-way switching valve, and the PCV valve. At the time of this abnormality diagnosis, fresh air flows into the intake passage via the first and third passages instead of blow-by gas.

  In order to achieve the above object, an invention according to claim 12 is an abnormality diagnosis device for diagnosing an abnormality of a blow-by gas reduction device for flowing blow-by gas generated in an engine to an intake passage and returning the blow-by gas to the engine, Is configured to generate a driving force in response to the supply of fuel and to shut off the supply of fuel during deceleration.The blow-by gas reducing device includes a blow-by gas storage unit for storing blow-by gas generated by the engine. , An intake amount control valve provided in the intake passage to adjust the amount of intake air flowing through the intake passage, and blow-by gas stored in the blow-by gas storage section flowing through the intake passage downstream of the intake amount control valve to be returned to the engine. A gas flow control valve for adjusting the flow rate of the blow-by gas in the blow-by gas return passage; An abnormality diagnosis device is provided with a fresh air introduction passage for introducing fresh air to the by-gas storage unit, and an intake air amount detecting means for detecting an intake air amount in an intake passage upstream of the intake air amount adjustment valve; A communication path for communicating between a blow-by gas reduction passage downstream of the control valve and the fresh air introduction passage, an on-off valve provided in the communication passage, and abnormality diagnosis means for diagnosing an abnormality of the blow-by gas reduction device; The abnormality diagnosis means controls the closing and opening of the on-off valve when the engine is decelerated and when the supply of fuel to the engine is interrupted, and the abnormality diagnosis means detects when the intake valve is closed by the intake air amount detecting means. The purpose of the present invention is to diagnose the abnormality of the blow-by gas reducing device based on the closed valve intake air amount and the valve open intake amount detected by the intake amount detecting means when the valve is opened.

  According to the configuration of the present invention, when the engine is decelerated and when the supply of fuel to the engine is cut off (during deceleration fuel cut), the abnormality of the blow-by gas reducing device is diagnosed. Here, during the deceleration fuel cut, no torque is generated in the engine, and the intake air amount adjustment valve is closed, and the intake air passing through the valve is constant in the sonic state. Therefore, it is possible to make a relatively large difference between the valve opening intake air amount detected when the on-off valve is controlled to open and the valve closing intake air amount detected when the valve is closed. In the sonic state of intake, even if the on-off valve is opened and closed, the amount of intake air passing through the intake air amount control valve does not change, and the opening degree of the on-off valve directly changes the intake air amount. Thus, the difference between the valve opening intake amount and the valve closing intake amount becomes relatively large.

  According to the first aspect of the present invention, it is possible to diagnose a perforated abnormality in the blow-by gas reducing device with high accuracy and in a relatively short time.

  According to the second aspect of the present invention, the accuracy of the abnormality diagnosis of the blow-by gas reducing device can be improved with respect to the effect of the first aspect of the present invention.

  According to the third aspect of the present invention, it is possible to improve the accuracy of the abnormality diagnosis with respect to the effect of the first aspect of the present invention.

  According to the fourth aspect of the present invention, it is possible to diagnose a perforated abnormality in the blow-by gas return passage accurately and in a relatively short time.

  According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the present invention, it is possible to diagnose a clogging abnormality in the blow-by gas return passage accurately and in a relatively short time.

  According to the sixth aspect of the present invention, it is possible to diagnose a perforated abnormality in the blow-by gas return passage accurately and in a relatively short time.

  According to the invention described in claim 7, in addition to the effect of the invention described in claim 6, it is possible to diagnose a clogging abnormality in the blow-by gas return passage accurately and in a relatively short time.

  According to the invention described in claim 8, in addition to the effect of the invention described in any one of claims 1 to 7, it is possible to improve the reliability of the perforated abnormality diagnosis in the blow-by gas reducing device.

  According to the ninth aspect of the present invention, in addition to the effects of the first aspect of the present invention, it is possible to simplify the diagnosis of the perforation abnormality in the blow-by gas return passage by the amount of omitting the piping. it can.

  According to the tenth aspect, in addition to the effects of the first to eighth aspects, the introduction of the blow-by gas and the introduction of the fresh air into the intake passage have a high response by a relatively simple configuration. You can switch to

  According to the eleventh aspect, in addition to the effect of the tenth aspect, it is possible to improve the accuracy of diagnosing a perforated abnormality in the blow-by gas reducing device, and to improve the oil from the crankcase at the time of abnormality diagnosis. Can be reduced.

  According to the twelfth aspect of the present invention, it is possible to diagnose a perforated abnormality in the blow-by gas returning device with high accuracy and in a relatively short time.

1 is a schematic configuration diagram illustrating a gasoline engine system according to a first embodiment. 5 is a flowchart showing the contents of first abnormality diagnosis control according to the first embodiment. 4 is a graph showing first determination data for abnormality diagnosis according to the first embodiment. 4 is a graph showing second determination data for abnormality diagnosis according to the first embodiment. 6 is a graph showing the first determination data and the second determination data collectively according to the first embodiment. 9 is a flowchart showing details of perforation abnormality diagnosis control based on an air-fuel ratio deviation according to the second embodiment. FIG. 9 is a graph showing a relationship between an intake opening amount and a perforated opening area of a pipe according to the second embodiment. FIG. 9 is a graph showing a relationship between an air-fuel ratio corrected fuel increase ratio and a perforated opening area of a pipe according to the second embodiment. 9 is a flowchart showing a part of the contents of a second abnormality diagnosis control according to the second embodiment. 13 is a flowchart showing another part of the content of the second abnormality diagnosis control according to the second embodiment. 13 is a flowchart showing the contents of third abnormality diagnosis control according to the third embodiment. 13 is a graph showing third determination data for abnormality diagnosis according to the third embodiment. FIG. 9 is a schematic configuration diagram illustrating a gasoline engine system according to a fourth embodiment. 14 is a flowchart showing the contents of fourth abnormality diagnosis control according to the fourth embodiment. 13 is a flowchart showing the contents of a switching process of a three-way switching valve according to the fourth embodiment. FIG. 9 is a schematic configuration diagram illustrating a gasoline engine system according to a fifth embodiment. 15 is a flowchart showing the contents of fifth abnormality diagnosis control according to the fifth embodiment. 15 is a graph showing fifth determination data for abnormality diagnosis according to the fifth embodiment. FIG. 13 is a schematic configuration diagram illustrating a gasoline engine system according to a sixth embodiment. FIG. 13 is a schematic configuration diagram showing a gasoline engine system according to a seventh embodiment. FIG. 4 is a schematic configuration diagram showing a gasoline engine system according to another embodiment.

<First embodiment>
Hereinafter, a first embodiment embodying an abnormality diagnosis device of a blow-by gas reduction device (hereinafter, referred to as “BGV device”) in the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of a gasoline engine system according to this embodiment. The engine 1 constituting this engine system includes an engine block 2 including a plurality of cylinders. A piston 3 is provided in each cylinder so as to be reciprocable. A crankcase 4 is provided below the engine block 2. The crankcase 4 is configured together with the oil pan 5. A crankshaft 6 is rotatably supported in the crankcase 4, and each piston 3 is connected to the crankshaft 6 via a connecting rod 7.

  In each cylinder, a combustion chamber 8 is formed above each piston 3. An intake port 9 and an exhaust port 10 are formed in the upper part of the engine block 2 corresponding to each combustion chamber 8. The intake port 9 is provided with an intake valve 11, and the exhaust port 10 is provided with an exhaust valve 12. Each of the intake valves 11 and each of the exhaust valves 12 are configured to open and close by a well-known valve train 13 in conjunction with the rotation of the crankshaft 6. When the intake valve 11 and the exhaust valve 12 open and close, outside air is drawn into the combustion chamber 8 from the intake port 9, and the exhaust gas after combustion is discharged from the combustion chamber 8 to the exhaust port 10. A head cover 14 that covers the valve mechanism 13 and the like is provided above the engine block 2.

  An intake passage 15 is connected to the intake port 9. An air cleaner 16 is provided at an inlet of the intake passage 15. An electric electronic throttle device 18 including a throttle valve 17 and a surge tank 19 are provided in the intake passage 15. The intake passage 15 downstream of the electronic throttle device 18 includes a well-known intake manifold 31 including a surge tank 19. The electronic throttle device 18 is configured to open and close the throttle valve 17 by a motor (not shown) in conjunction with the operation of an accelerator pedal (not shown) provided in the driver's seat. The electronic throttle device 18 corresponds to an example of the intake air amount adjusting means of the present invention. The surge tank 19 has a function of suppressing pulsation of intake air flowing through the intake passage 15. The air purified by the air cleaner 16 is sucked into each combustion chamber 8 through the intake passage 15, the electronic throttle device 18, and the intake port 9. The amount of intake air (the amount of intake air) is adjusted according to the opening of the throttle valve 17. The engine block 2 is provided with an injector 20 for injecting and supplying fuel to each of the combustion chambers 8. The fuel injected from each injector 20 into each combustion chamber 8 forms an air-fuel mixture with the intake air. An ignition plug 21 for igniting the air-fuel mixture in each combustion chamber 8 is provided above the engine block 2. The ignition plug 21 operates when a high voltage is applied from the igniter 22.

  An exhaust passage 23 including an exhaust manifold is connected to the exhaust port 10. The burned exhaust gas generated in each combustion chamber 8 is discharged outside through the exhaust port 10 and the exhaust passage 23 and the like.

  In this embodiment, in this gasoline engine system, a BGV that causes blow-by gas generated in each combustion chamber 8 to flow to the intake passage 15 (intake manifold 31) downstream of the electronic throttle device 18 (throttle valve 17) and return to the engine 1 Equipment. This device includes a blow-by gas storage unit for storing blow-by gas generated in the engine 1. The blow-by gas storage unit includes a crankcase 4 and a head cover 14. The crankcase 4 and the head cover 14 communicate with each other via a communication passage 2 a provided in the engine block 2. An oil separator 24 is provided in the crankcase 4. The oil separator 24 has a function of separating and capturing oil such as lubricating oil mixed in the blow-by gas from the blow-by gas inside the crankcase 4. Between the oil separator 24 and the intake passage 15 (intake manifold 31) downstream of the throttle valve 17, a blow-by gas returning passage (hereinafter referred to as “BGV passage”) for flowing blow-by gas from the crankcase 4 to the intake passage 15. 26) are provided. The BGV passage 26 is configured by a pipe such as a hose. Further, the intake manifold 31 is provided with a PCV valve 27 for adjusting the flow rate of the blow-by gas. Here, the PCV valve 27 is a well-known electrically operated valve configured to have a variable opening, and is directly attached (directly attached) to the intake manifold 31 without passing through piping or the like. The PCV valve 27 corresponds to an example of the gas flow rate adjusting means of the present invention. Between the intake passage 15 upstream of the throttle valve 17 and the head cover 14, new air for introducing fresh air (outside air) into the head cover 14 in order to scavenge blow-by gas in the head cover 14 and the crankcase 4. An air introduction passage 28 is provided. Fresh air introduced into the head cover 14 is guided into the crankcase 4 through the communication passage 2a.

  The above-described engine system further includes an electronic control unit (ECU) 50. The air cleaner 16 is provided with an air flow meter 51 for detecting an intake air amount Ga flowing through the intake passage 15. The air flow meter 51 corresponds to an example of the intake air amount detecting means of the present invention. The electronic throttle device 18 is provided with a throttle sensor 52 for detecting the opening degree (throttle opening degree) TA of the throttle valve 17. The surge tank 19 is provided with an intake pressure sensor 53 for detecting an intake pressure PM in the intake passage 15. The engine block 2 is provided with a rotation speed sensor 54 for detecting the rotation angle (crank angle) of the crankshaft 6 as the engine rotation speed NE. The engine block 2 is provided with a water temperature sensor 55 for detecting a temperature (cooling water temperature) THW of cooling water flowing inside the engine block 2. An oxygen sensor 56 for detecting the oxygen concentration Ox in the exhaust gas is provided in the exhaust passage 23. This oxygen sensor 56 corresponds to an example of the air-fuel ratio detecting means of the present invention. These various sensors 51 to 56 correspond to an example of an operating state detecting means for detecting the operating state of the engine 1. The ECU 50 performs fuel injection control including air-fuel ratio control based on the intake air amount Ga, the throttle opening TA, the intake pressure PM, the engine rotation speed NE, the cooling water temperature THW, and the oxygen concentration Ox detected by various sensors 51 to 56 and the like. , An ignition timing control, a blow-by gas reduction control, and the like. In the fuel injection control, the ECU 50 controls each injector 20 according to the operating state of the engine 1 to supply fuel to the engine 1. The engine 1 receives the supply of the fuel and generates a driving force. When the engine 1 is decelerated, the ECU 50 stops the fuel injection from the injector 20 and shuts off the fuel supply to the engine 1 (fuel cut) under a predetermined condition. In the ignition timing control, the ECU 50 controls the ignition plug 21 by operating the igniter 22 according to the operating state of the engine 1. In the blow-by gas reduction control, the ECU 50 controls the PCV valve 27 according to the operating state of the engine 1. In this embodiment, the ECU 50 corresponds to an example of the abnormality diagnosis means of the present invention.

  The above-described engine system further includes an abnormality diagnosis device for diagnosing an abnormality of the BGV device. This abnormality diagnosis device includes abnormality diagnosis means for diagnosing abnormality of the BGV passage 26 and the PCV valve 27. In this embodiment, the ECU 50 corresponds to an example of the abnormality diagnosis unit. The ECU 50 executes abnormality diagnosis control for diagnosing abnormality of the BGV passage 26 and the PCV valve 27.

  Here, as an abnormal mode of the BGV passage 26 and the PCV valve 27, a pipe (a hose or the like) constituting the BGV passage 26 is disconnected, a hole in the pipe is clogged, the pipe is clogged, and the PCV valve 27 is opened or closed. It can be assumed that they are fixed in a state.

  Next, the first abnormality diagnosis control executed by the ECU 50 will be described. FIG. 2 is a flowchart showing the contents of the abnormality diagnosis control. FIG. 3 is a graph showing first determination data used for abnormality diagnosis. FIG. 4 is a graph showing second determination data used for abnormality diagnosis. FIG. 5 is a graph collectively showing the first determination data and the second determination data.

  When the process proceeds to the routine shown in FIG. 2, in step 100, the ECU 50 determines whether or not the abnormality diagnosis flag XOBD is “0”, that is, whether or not abnormality diagnosis has not been performed. This flag XOBD is set to “1” when abnormality diagnosis is executed as described later. The ECU 50 shifts the processing to step 110 when the result of this determination is affirmative, and returns the processing to step 100 when the result of this determination is negative.

  In step 110, the ECU 50 determines whether or not the deceleration fuel cut is being performed. That is, it is determined whether or not the time of deceleration of the engine 1 and the time when the supply of fuel (fuel injection) from the injector 20 to the engine 1 is cut off. When the engine 1 is decelerated, the ECU 50 controls the electronic throttle device 18 to close the throttle valve 17 and shut off the fuel injection from the injector 20 under predetermined conditions. Therefore, during this deceleration fuel cut, no torque is generated in the engine 1 and the throttle valve 17 is closed, so that the intake air passing through the throttle valve 17 is constant in the sonic state. The ECU 50 shifts the processing to step 120 if the judgment result is affirmative, and returns the processing to step 100 if the judgment result is negative.

  In step 120, the ECU 50 controls the PCV valve 27 to the opening degree OP0. That is, the ECU 50 controls the PCV valve 27 to be fully closed.

  Next, at step 130, the ECU 50 takes in the intake air amount Ga when the opening degree of the PCV valve 27 is controlled to zero OP0 based on the detection value of the air flow meter 51.

  Next, in step 140, the ECU 50 sets the intake air amount Ga taken in in step 130 as the 0-opening intake air amount PCVGa0. The zero-opening intake air amount PCVGa0 corresponds to an example of a zero intake air amount of the present invention.

  Next, in step 150, the ECU 50 controls the PCV valve 27 to the first opening degree OP1. Here, the first opening OP1 means a predetermined opening that is larger than the opening zero OP0 and smaller than the full opening.

  Next, at step 160, the ECU 50 takes in the intake air amount Ga when the PCV valve 27 is controlled to the first opening degree OP1 based on the detection value of the air flow meter 51.

  Next, in step 170, the ECU 50 sets the intake air amount Ga taken in in step 160 as one opening degree intake air amount PCVGa1. The one opening degree intake air amount PCVGa1 corresponds to an example of the first intake air amount of the present invention.

  Next, in step 180, the ECU 50 controls the PCV valve 27 to the second opening degree OP2. Here, the second opening OP2 means a predetermined opening that is larger than the first opening OP1 and smaller than the full opening.

  Next, at step 190, the ECU 50 takes in the intake air amount Ga when the PCV valve 27 is controlled to the second opening OP2 based on the detection value of the air flow meter 51.

  Next, in step 200, the ECU 50 sets the intake air amount Ga taken in in step 190 as the two-opening intake air amount PCVGa2. This two-opening intake air amount PCVGa2 corresponds to an example of the second intake air amount of the present invention.

  Next, in step 210, the ECU 50 calculates the difference between the one-opening intake air amount PCVGa0 and the zero-opening intake air amount PCVGa0 as the one-opening intake air increase ΔPCVGa1. That is, the 0-opening intake air amount PCVGa0 is used as the reference intake air amount, and the increase amount of the 1-opening intake air amount PCVGa1 is calculated. This 1-opening intake air increase ΔPCVGa1 corresponds to an example of the first intake air increase of the present invention.

  Next, at step 220, the ECU 50 calculates the difference between the two-opening intake air amount PCVGa2 and the zero-opening intake air amount PCVGa0 as the two-opening intake air increase ΔPCVGa2. That is, the 0-opening intake air amount PCVGa0 is used as the reference intake air amount, and the increase of the 2-opening intake air amount PCVGa2 is calculated. The two-opening intake air increase ΔPCVGa2 corresponds to an example of the second intake air increase of the present invention.

  Thereafter, in step 230, the ECU 50 determines whether or not the one-opening intake air increase ΔPCVGa1 when the PCV valve 27 is controlled to the first opening OP1 is larger than a predetermined value A1. If the determination result is affirmative, ECU 50 shifts the processing to step 240, and if the determination result is negative, shifts the processing to step 280. This predetermined value A1 corresponds to an example of a third predetermined value of the present invention.

  Next, at step 240, the ECU 50 determines whether or not the two-opening intake air increase ΔPCVGa2 when the PCV valve 27 is controlled to the second opening OP2 is larger than a predetermined value C1 (C1> A1). The ECU 50 shifts the processing to step 250 if the judgment result is affirmative, and shifts the processing to step 260 if the judgment result is negative. This predetermined value C1 corresponds to an example of a fourth predetermined value of the present invention.

  In step 250, the ECU 50 determines that the flow rate of the blow-by gas and the piping are normal. The ECU 50 can store the normality determination in the memory.

  This determination will be described with reference to first determination data shown in FIG. In FIG. 3, the horizontal axis indicates the flow rate of the PCV valve 27 (the flow rate of blow-by gas flowing through the PCV valve 27 (hereinafter, the same applies)), and the vertical axis indicates the values of the 1-opening intake air increase ΔPCVGa1 and the 2-opening intake air increase ΔPCVGa2. Is shown. “(OP0), (OP1), (OP2)” on the horizontal axis means the flow rate of the PCV valve 27 corresponding to the opening degree OP0, the first opening degree OP1, and the second opening degree OP2 (hereinafter, referred to as “OPO”). 4, 5, and 12). If the determination result in step 240 is affirmative, the 1-opening intake air increase ΔPCVGa1 with respect to the flow rate of the PCV valve 27 when the PCV valve 27 is controlled to the first opening OP1 is larger than the predetermined value A1 and the PCV valve 27 Is controlled to the second opening OP2, the two-opening intake increase ΔPCVGa2 with respect to the flow rate of the PCV valve 27 is larger than a predetermined value C1. The change from the 1-opening intake air increase ΔPCVGa1 to the 2-opening intake air increase ΔPCVGa2 is located above, for example, a straight line A1-C1 (small hole determination) connecting “A1” and “C1” shown in FIG. It is considered that a linear change occurs on a straight line L1 (normal) passing through the origin. In this case, it can be determined that the BGV device is normal.

  Then, in step 270, the ECU 50 sets the abnormality diagnosis flag XOBD to “1”, and returns the processing to step 100.

  On the other hand, after the process proceeds from step 240 to step 260, the ECU 50 determines that there is a pipe clogging abnormality having a small blockage in the pipe (BGV passage 26), and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  This determination will be described with reference to the second determination data shown in FIG. If the determination result in step 240 is negative, the 1-opening intake air increase ΔPCVGa1 is larger than the predetermined value A1, and the 2-opening intake air increase ΔPCVGa2 is equal to or less than the predetermined value C1. Then, the change from the 1-opening intake air increase .DELTA.PCVGa1 to the 2-opening intake air increase .DELTA.PCVGa2 is located, for example, below the curved line passing through "C1" shown in FIG. It is considered that the curve changes on L2 (small clogging). In this case, it can be determined that the BGV passage 26 has a small clogging abnormality.

  On the other hand, in step 280 after shifting from step 230, the ECU 50 determines whether or not the 1-opening intake air increase amount ΔPCVGa1 is larger than a predetermined value B1 (C1> A1> B1). If the determination result is affirmative, ECU 50 shifts the processing to step 290, and if the determination result is negative, shifts the processing to step 320.

  In step 290, the ECU 50 determines whether or not the two-opening intake air amount increase ΔPCVGa2 is larger than a predetermined value D1 (C1> D1> A1> B1). The ECU 50 shifts the processing to step 300 if the judgment result is affirmative, and shifts the processing to step 310 if the judgment result is negative.

  In step 300, the ECU 50 determines that there is a pipe small hole abnormality having a small hole in the pipe (BGV passage 26), and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result in step 290 is affirmative, the 1-opening intake air increase ΔPCVGa1 becomes equal to or less than the predetermined value A1 and becomes larger than the predetermined value B1, and the 2-opening intake air increase ΔPCVGa2 becomes larger than the predetermined value D1 (<C1). large. Then, the change from the 1-opening intake air increase .DELTA.PCVGa1 to the 2-opening intake air increase .DELTA.PCVGa2 is located above, for example, a straight line B1-D1 connecting "B1" and "D1" shown in FIG. It is considered that the change is linear on a straight line L3 (small hole) located below C1 (small hole judgment) and passing through the origin. In this case, it can be determined that the BGV passage 26 has a small hole abnormality.

  On the other hand, after the process proceeds from step 290 to step 310, the ECU 50 determines that there is a pipe clogging abnormality having a large blockage in the pipe (BGV passage 26), and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result of step 290 is negative, the 1-opening intake air increase ΔPCVGa1 becomes equal to or less than the predetermined value A1 and becomes larger than the predetermined value B1, and the 2-opening intake air increase ΔPCVGa2 becomes equal to or less than the predetermined value D1 (<C1). Becomes Then, the change from the 1-opening intake air increase ΔPCVGa1 to the 2-opening intake air increase ΔPCVGa2 is located, for example, below the broken line A1-D1 (large clogging determination) passing through “A1” and “D1” shown in FIG. However, it is considered that the curve changes on a curved broken line L4 (large clogging) passing through the origin. In this case, it can be determined that the BGV passage 26 has a large blockage abnormality.

  On the other hand, after shifting from step 280 to step 320, the ECU 50 determines that the two-opening intake air amount increase ΔPCVGa2 is smaller than the predetermined value E1 (C1> D1> A1> E1> B1) and the predetermined value F1 (C1> D1> A1> E1). > B1> F1). If the determination result is affirmative, ECU 50 shifts the processing to step 330, and if the determination result is negative, shifts the processing to step 340.

  In step 330, the ECU 50 determines that there is a pipe large hole abnormality having a large hole in the pipe (BGV passage 26), and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  When the determination result of step 320 is affirmative, the 1-opening intake air increase ΔPCVGa1 becomes equal to or less than the predetermined value A1 and the predetermined value B1 or less, and the 2-opening intake air increase ΔPCVGa2 is smaller than the predetermined value E1 and becomes smaller than the predetermined value F1. growing. Then, the change from the 1-opening intake air increase .DELTA.PCVGa1 to the 2-opening intake air increase .DELTA.PCVGa2 is located, for example, below the straight line B1-E1 (large hole determination) connecting "B1" and "E1" shown in FIG. It is considered that a linear change occurs on a straight line L5 (large hole) passing through the origin. In this case, it can be determined that the BGV passage 26 has a large hole abnormality.

  On the other hand, in step 340 after shifting from step 320, the ECU 50 determines that the PCV valve 27 is in a sticking abnormality in which the PCV valve 27 is fixed at a certain opening, and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result in step 320 is negative, the 1-opening intake air increase ΔPCVGa1 becomes equal to or less than the predetermined value A1 and the predetermined value B1 or less, and the 2-opening intake air increase ΔPCVGa2 is larger than the predetermined value E1 or the predetermined value F1. Less than. Then, the change from the 1-opening intake air increase ΔPCVGa1 to the 2-opening intake air increase ΔPCVGa2 is located below, for example, a straight line F1-F1 (fixation determination) connecting “F1” and “F1” shown in FIG. It is considered that the change is linear on a straight line L6 (fixed) passing through the origin. In this case, it can be determined that the PCV valve 27 is stuck abnormally.

  According to the abnormality diagnosis device for a BGV device in this embodiment described above, the abnormality of the BGV device is diagnosed when the deceleration fuel cut of the engine 1 is performed. Here, during the deceleration fuel cut, no torque is generated in the engine 1, the throttle valve 17 of the electronic throttle device 18 is closed, and the intake air passing through the throttle valve 17 is constant in the sonic state. Accordingly, the one-opening intake air amount PCVGa1 detected when the PCV valve 27 is controlled to the first opening OP1 and the two-opening intake air amount PCVGa2 detected when the PCV valve 27 is controlled to the second opening OP2. The difference can be made relatively large. In the sonic state of the intake air, even if the opening of the PCV valve 27 is changed, the amount of intake air passing through the electronic throttle device 18 does not change, and the change in the opening of the valve 27 directly changes the amount of intake air. That is, the difference between the one-opening intake air amount PCVGa1 and the two-opening intake air amount PCVGa2 becomes relatively large. For this reason, it is possible to secure a change in the flow rate necessary for determining a hole abnormality such as a large or small hole in the pipe of the BGV passage 26. As a result, it is possible to accurately diagnose a large or small perforated abnormality relating to the piping of the BGV passage 26. Further, in order to ensure the accuracy of the abnormality determination, it is not necessary to take time for the determination, and the abnormality diagnosis can be performed in a relatively short time.

  In this embodiment, the differences between the 1-opening intake air amount PCVGa1 and the 2-opening intake air amount PCVGa2 and the reference 0-opening intake air amount PCVGa0 are calculated as a 1-opening intake air increase ΔPCVGa1 and a 2-opening intake air increase ΔPCVGa2, respectively. You. Therefore, the influence of the individual difference of the air flow meter 51 is reduced in the 1-opening intake air increase ΔPCVGa1 and the 2-opening intake air increase ΔPCVGa2. Further, since the 1-opening intake air increase ΔPCVGa1 is compared with its own predetermined values A1, B1, F1, and the 2-opening intake increase ΔPCVGa2 is compared with its own predetermined values C1, D1, E1, F1. A change in the intake air amount when the PCV valve 27 is changed from the first opening OP1 to the second opening OP2 is properly confirmed. For this reason, the accuracy of the abnormality diagnosis of the BGV device can be improved.

  In this embodiment, the 1-opening intake air increase ΔPCVGa1 is larger than the predetermined value A1, the 2-opening intake air increase ΔPCVGa2 is larger than the predetermined value C1, and the 1-opening intake air increase ΔPCVGa1 is changed to the 2-opening intake air increase ΔPCVGa2. If the change is a linear change, it is determined that the BGV device is normal. Further, the 1-opening intake air increase ΔPCVGa1 becomes equal to or less than a predetermined value A1, the 2-opening intake air increase ΔPCVGa2 becomes equal to or less than a predetermined value C1, and the change from the 1-opening intake increase ΔPCVGa1 to the 2-opening intake increase ΔPCVGa2 is linear. When the target change occurs, it is determined that the BGV passage 26 has a perforated abnormality. Under these conditions, it is easy to determine whether there is a hole in the BGV passage 26 or not. In this sense, it is possible to diagnose a large or small hole abnormality in the BGV passage 26 with high accuracy and in a relatively short time.

  In this embodiment, when the two-opening intake increase .DELTA.PCVGa2 is equal to or less than the predetermined value C1, and the change from the one-opening intake increase .DELTA.PCVGa1 to the two-opening intake increase .DELTA.PCVGa2 is a curved change, the BGV passage 26 Is determined to be a clogging abnormality. Under such conditions, the clogging abnormality of the BGV passage 26 is easily determined. In this sense as well, it is possible to diagnose a clogging abnormality in the BGV passage 26 with high accuracy and in a relatively short time.

  According to this embodiment, since the PCV valve 27 is directly attached to the intake manifold 31 that forms the intake passage 15, there is no piping between the intake manifold 31 and the PCV valve 27, and a perforated abnormality corresponds to the amount of the piping. Are omitted. Therefore, diagnosis of a perforated abnormality in the BGV passage 26 can be simplified accordingly.

<Second embodiment>
Next, a second embodiment embodying the abnormality diagnosis device for a BGV device according to the present invention will be described in detail with reference to the drawings.

  In the following description, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted, and different points will be mainly described.

  This embodiment differs from the first embodiment in the contents of the abnormality diagnosis control. Here, if there is a hole in the piping of the BGV passage 26, the amount of air taken into the combustion chamber 8 becomes larger than the amount of intake air Ga detected by the air flow meter 51. / F shifts to the lean side. On the other hand, when the pipe of the BGV passage 26 is clogged, the air-fuel ratio A / F does not shift to the lean side during the operation of the engine 1. Therefore, by performing the abnormality diagnosis based on the determination of the deviation of the air-fuel ratio A / F together with the abnormality diagnosis control of the first embodiment, it is possible to more accurately diagnose the BGV passage 26 with holes and clogs. In this embodiment, the engine 1 is susceptible to the difference in the air-fuel ratio A / F during the idling operation, so that the idling of the air-fuel ratio A / F is diagnosed during the idling operation.

  FIG. 6 is a flowchart showing the details of the perforation abnormality diagnosis control based on the deviation of the air-fuel ratio A / F. When the process proceeds to this routine, in step 400, the ECU 50 determines whether or not a perforated abnormality diagnosis flag XOBDAF is “0”. As will be described later, this flag XOBDAF is set to “1” when the perforation abnormality diagnosis is executed, and is set to “0” when the perforation abnormality diagnosis is not executed. Therefore, the ECU 50 shifts the process to step 410 if the result of this determination is affirmative (perforation abnormality diagnosis not performed), and proceeds to step 400 if the result of this determination is negative (perforation abnormality diagnosis execution). Return to

  In step 410, the ECU 50 determines whether the engine 1 is idle. The ECU 50 can make this determination based on the detection value of the throttle sensor 52 and the detection value of the rotation speed sensor 54, for example. The ECU 50 shifts the processing to step 420 if this judgment result is affirmative, and returns the processing to step 400 if this judgment result is negative.

  In step 420, the ECU 50 determines whether the air-fuel ratio A / F is stoichiometric. The ECU 50 can make this determination based on the detection value of the oxygen sensor 56. If the determination result is affirmative, ECU 50 shifts the processing to step 430. If the determination result is negative, ECU 50 returns the processing to step 400.

  In step 430, the ECU 50 takes in the air-fuel ratio corrected fuel increase ratio KFL. The increase ratio KFL means a ratio of the air-fuel ratio corrected fuel amount to the reference value when the air-fuel ratio corrected fuel amount is increased. Here, FIG. 7 is a graph showing the relationship of the intake air amount Ga detected by the air flow meter 51 to the opening area of the pipe of the BGV passage 26. As can be seen from this graph, as the perforated opening area of the pipe increases, the detected intake air amount Ga gradually decreases with respect to the reference intake air amount Ga at idle (with no holes). As a result, in the fuel injection control, the fuel injection amount from the injector 20 decreases, and the air-fuel ratio A / F shifts from the reference value to the lean side. Therefore, in the air-fuel ratio control, the ECU 50 increases the air-fuel ratio corrected fuel amount, and as a result, the air-fuel ratio corrected fuel increase ratio KFL increases. In this embodiment, the ECU 50 calculates the air-fuel ratio corrected fuel increase ratio KFL based on the detection value of the oxygen sensor 56 in the air-fuel ratio control. In this regard, the ECU 50 and the oxygen sensor 56 correspond to an example of the air-fuel ratio calculating means of the present invention. FIG. 8 is a graph showing the relationship between the air-fuel ratio corrected fuel increase ratio KFL and the hole opening area of the piping of the BGV passage 26. As can be seen from this graph, as the perforated opening area of the pipe increases (as the detected intake air amount Ga decreases), the air-fuel ratio corrected fuel increase ratio KFL deviates from the reference “1.0”. Increase gradually. Therefore, in step 430, the ECU 50 takes in the air-fuel ratio corrected fuel increase ratio KFL at this time.

  Next, at step 440, the ECU 50 determines whether or not the taken air-fuel ratio corrected fuel increase ratio KFL is smaller than a predetermined value G1. As shown in FIG. 8, the predetermined value G1 is a reference value for determining that the perforated opening area of the pipe is a small hole, and when the air-fuel ratio correction fuel increase ratio KFL is smaller than the predetermined value G1, Indicates that there is no hole in the piping. Therefore, the ECU 50 shifts the processing to step 450 if this determination result is affirmative, and shifts the processing to step 470 if this determination result is negative.

  In step 450, the ECU 50 determines that there is no hole in the pipe. At this time, the air-fuel ratio A / F determination becomes “normal”. The ECU 50 can store the hole absence determination in the memory.

  Next, at step 460, the ECU 50 sets the perforation abnormality diagnosis flag XOBDAF to “1”, and returns the processing to step 400.

  On the other hand, in step 470, the ECU 50 determines whether the taken air-fuel ratio corrected fuel increase ratio KFL is smaller than a predetermined value H1. As shown in FIG. 8, the predetermined value H1 is a reference value for determining that the hole opening area of the pipe is a large hole, and when the air-fuel ratio corrected fuel increase ratio KFL is smaller than the predetermined value H1, Indicates that there are no large holes in the piping. Therefore, the ECU 50 shifts the processing to step 480 if this determination result is affirmative, and shifts the processing to step 490 if this determination result is negative.

  In step 480, the ECU 50 determines that there is a small hole in the pipe. At this time, the air-fuel ratio A / F determination is “abnormal”. The ECU 50 can store the small hole presence determination in the memory. Thereafter, the ECU 50 shifts the processing to Step 460.

  On the other hand, in step 490, the ECU 50 determines that there is a large hole in the pipe. At this time, the air-fuel ratio A / F determination is “abnormal”. The ECU 50 can store the large hole presence determination in the memory. Thereafter, the ECU 50 shifts the processing to Step 460.

  Next, the second abnormality diagnosis control executed by the ECU 50 will be described. 9 and 10 show the contents of the abnormality diagnosis control in the form of flowcharts. The flowcharts of FIGS. 9 and 10 are different from the flowchart of FIG. 2 in that steps 500 to 560 are added to steps 100 to 340 in the flowchart of FIG.

  When the processing shifts to the routines of FIGS. 9 and 10, the ECU 50 executes the processing of steps 100 to 240, step 280, step 290, and step 320. Then, in step 500, which has proceeded from step 240, the ECU 50 determines whether there is no hole in the piping of the BGV passage 26. The ECU 50 makes this determination with reference to the determination result obtained in the routine of FIG. When the determination result is affirmative, ECU 50 shifts the processing to step 260, and when the determination result is negative, shifts the processing to step 560.

  In step 260, the ECU 50 determines that there is a pipe clogging abnormality. However, in step 500, since it is confirmed that the pipe has no hole, the determination of the small clogging abnormality in this step 260 is more reliable. It becomes something.

  On the other hand, in step 560 after shifting from step 500, the ECU 50 suspends the determination and returns the processing to step 100.

  In step 510 after shifting from step 240, the ECU 50 determines whether there is no hole in the pipe as in step 500. If the determination result is affirmative, ECU 50 shifts the processing to step 250. If the determination result is negative, ECU 50 shifts the processing to step 560.

  In step 250, the ECU 50 determines that the flow rate of the blow-by gas and the piping are normal. However, in step 510, it is confirmed that the piping has no holes. It will be certain.

  On the other hand, after shifting from step 290 to step 520, the ECU 50 determines whether or not there is a small hole in the piping of the BGV passage 26. The ECU 50 makes this determination with reference to the determination result obtained in the routine of FIG. If the determination result is affirmative, ECU 50 shifts the processing to step 300, and if the determination result is negative, shifts the processing to step 560.

  In step 300, the ECU 50 determines that there is an abnormality in the piping small hole. However, in step 520, it is confirmed that there is a small hole in the piping. Is more reliable.

  In step 530 after shifting from step 290, the ECU 50 determines whether there is no hole in the pipe as in step 500. If the determination result is affirmative, ECU 50 shifts the processing to step 310, and if the determination result is negative, shifts the processing to step 560.

  In step 310, the ECU 50 determines that there is a pipe clogging abnormality. However, in step 530, since it is confirmed that there is no hole in the pipe, it is determined that there is a pipe clogging abnormality in this step 310. The judgment is more reliable.

  On the other hand, after shifting from step 320 to step 540, the ECU 50 determines whether or not the pipe has a large hole. The ECU 50 makes this determination with reference to the determination result obtained in the routine of FIG. When the determination result is affirmative, ECU 50 shifts the processing to step 330, and when the determination result is negative, shifts the processing to step 560.

  In step 330, the ECU 50 determines that there is a pipe large hole abnormality. However, in step 540, since it is confirmed that the pipe has a large hole, it is determined in step 330 that the pipe large hole is abnormal. Is more reliable.

  In step 550 after shifting from step 320, the ECU 50 determines whether or not there is a hole in the pipe as in step 500. The ECU 50 shifts the processing to step 340 if the result of this determination is positive, and shifts the processing to step 560 if the result of this determination is negative.

  In step 340, the ECU 50 determines that the PCV valve 27 is stuck at a certain opening degree. However, in step 550, it is confirmed that there is no hole in the pipe. The determination that the sticking is abnormal is more reliable.

  According to the abnormality diagnosis device for a BGV device in this embodiment described above, the following operation and effect can be obtained in addition to the operation and effect of the first embodiment. That is, in this embodiment, the ECU 50 determines whether the BGV passage 26 has a hole abnormality based on the deviation of the calculated air-fuel ratio A / F from the predetermined reference value, together with the abnormality diagnosis based on the detected intake air amount Ga. Whether or not there is is diagnosed. Accordingly, in addition to the abnormality diagnosis based on the intake air amount Ga, the presence or absence of the perforated abnormality in the BGV passage 26 is diagnosed based on the deviation of the air-fuel ratio A / F, so that the diagnosis regarding the perforated abnormality is more reliable. . For this reason, the reliability of the perforated abnormality diagnosis in the BGV device can be improved.

<Third embodiment>
Next, a third embodiment embodying the abnormality diagnosis device for a BGV device according to the present invention will be described in detail with reference to the drawings.

  This embodiment is different from the above embodiments in the content of the abnormality diagnosis control. In each of the above embodiments, in FIGS. 2 and 9, in steps 210 and 220, the one-opening intake air increase ΔPCVGa1 and the two-opening intake increase ΔPCVGa2 are calculated, and in steps 230 to 340 thereafter, the one-opening intake air increase ΔPCVGa1 is calculated. The abnormality of the BGV device is diagnosed on the basis of the increase ΔPCVGa1 and the two-opening intake increase ΔPCVGa2. On the other hand, in this embodiment, the processing of steps 210 and 220 is omitted, and the abnormality of the BGV device is diagnosed simply based on the one-opening intake air amount PCVGa1 and the two-opening intake air amount PCVGa2 that are the intake air amounts Ga. It is composed.

  FIG. 11 is a flowchart showing the contents of the third abnormality diagnosis control. FIG. 12 is a graph showing third determination data used for abnormality diagnosis. In the flowchart shown in FIG. 11, steps 210 and 220 in the flowchart of FIG. 2 are eliminated, and instead of steps 230, 240, 280, 290 and 320, steps 235, 245, 285, 295 and 325 are performed. 2 is different from the flowchart of FIG.

  When the processing shifts to the routine shown in FIG. 11, the ECU 50 executes the processing of steps 100 to 200, and shifts to step 235. In step 235, the ECU 50 determines whether or not the one-opening intake air amount PCVGa1 is larger than a predetermined value a1. This predetermined value a1 corresponds to an example of a first predetermined value of the present invention. The ECU 50 shifts the processing to step 245 if the judgment result is affirmative, and shifts the processing to step 285 if the judgment result is negative.

  In step 245, the ECU 50 determines whether or not the two-opening intake air amount PCVGa2 is larger than a predetermined value c1 (c1> a1). This predetermined value c1 corresponds to an example of a second predetermined value of the present invention. The ECU 50 shifts the processing to step 250 if the judgment result is affirmative, and shifts the processing to step 260 if the judgment result is negative.

  In step 250, the ECU 50 determines that the flow rate of the blow-by gas and the piping are normal. The ECU 50 can store the normality determination in the memory.

  This determination will be described with reference to third determination data shown in FIG. 12, the horizontal axis indicates the flow rate of the PCV valve 27, and the vertical axis indicates the one-opening intake air amount PCVGa1 and the two-opening intake air amount PCVGa2. If the determination result in step 245 is affirmative, the one-opening intake air amount PCVGa1 with respect to the flow rate of the PCV valve 27 when the PCV valve 27 is controlled to the first opening degree OP1 is larger than the predetermined value a1 and the PCV valve 27 Is controlled to the second opening OP2, the two-opening intake air amount PCVGa2 with respect to the flow rate of the PCV valve 27 is larger than a predetermined value c1. Then, the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is located above, for example, a straight line a1-c1 (small hole determination) connecting “a1” and “c1” shown in FIG. It is considered that a linear change occurs on a straight line L11 (normal) that does not pass through the origin. In this case, it can be determined that the BGV device is normal.

  Then, in step 270, the ECU 50 sets the abnormality diagnosis flag XOBD to “1”, and returns the processing to step 100.

  On the other hand, after the process proceeds from step 245 to step 260, the ECU 50 determines that there is a pipe clogging abnormality, and proceeds to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result in step 245 is negative, the one-opening intake air amount PCVGa1 is larger than the predetermined value a1, and the two-opening intake air amount PCVGa2 is equal to or less than the predetermined value c1. The change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is located, for example, below a broken line (decision of small clogging) passing through "c1" shown in FIG. It is considered that the curve changes on the broken line L12 (clogging). In this case, it can be determined that the BGV passage 26 has a small clogging abnormality.

  On the other hand, after the process proceeds from step 235, in step 285, the ECU 50 determines whether or not the one-opening intake air amount PCVGa1 is larger than a predetermined value b1 (c1> a1> b1). The ECU 50 shifts the processing to step 295 if the judgment result is affirmative, and shifts the processing to step 325 if the judgment result is negative.

  In step 295, the ECU 50 determines whether or not the two-opening intake air amount PCVGa2 is larger than a predetermined value d1 (c1> d1> a1> b1). The ECU 50 shifts the processing to step 300 if the judgment result is affirmative, and shifts the processing to step 310 if the judgment result is negative.

  In step 300, the ECU 50 determines that there is an abnormality in the piping small hole, and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result of step 295 is affirmative, the 1-opening intake air amount PCVGa1 becomes equal to or less than the predetermined value a1 and becomes larger than the predetermined value b1, and the 2-opening intake air amount PCVGa2 becomes larger than the predetermined value d1 (<c1). large. Then, the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is located above, for example, “b1” and “d1” shown in FIG. 12 and connects “a1” and “c1”. It is considered that the change is linear on a straight line L13 (small hole) located below the straight line a1-c1 (small hole determination) and not passing through the origin. In this case, it can be determined that the BGV passage 26 has a small hole abnormality.

  On the other hand, after the process proceeds from step 295 to step 310, the ECU 50 determines that there is a large pipe clogging abnormality, and proceeds to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result in step 295 is negative, the one-opening intake air amount PCVGa1 becomes equal to or less than the predetermined value a1 and becomes larger than the predetermined value b1, and the two-opening intake air amount PCVGa2 becomes equal to or less than the predetermined value d1. Then, the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is, for example, below the curved broken line (large blockage determination) passing through "d1" shown in FIG. It is considered that the curve changes on a broken line L14 (large blockage). In this case, it can be determined that the BGV passage 26 has a large blockage abnormality.

  On the other hand, in step 325 after shifting from step 285, the ECU 50 determines that the two-opening intake air amount PCVGa2 is smaller than the predetermined value e1 (c1> d1> a1> e1> b1) and the predetermined value f1 (c1> d1> a1> e1). > B1> f1). If the determination result is affirmative, ECU 50 shifts the processing to step 330, and if the determination result is negative, shifts the processing to step 340.

  In step 330, the ECU 50 determines that there is a pipe large hole abnormality, and shifts the processing to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  When the determination result of step 325 is affirmative, the 1-opening intake air amount PCVGa1 is equal to or less than the predetermined value a1 and is equal to or less than the predetermined value b1, and the 2-opening intake air amount PCVGa2 is smaller than the predetermined value e1 and is smaller than the predetermined value f1. growing. Then, the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is located, for example, below the straight line b1-e1 (large hole determination) connecting "b1" and "e1" shown in FIG. It is considered that the change is linear on a straight line L15 (large hole) that does not pass through the origin. In this case, it can be determined that the BGV passage 26 has a large hole abnormality.

  On the other hand, after the process proceeds from step 325 to step 340, the ECU 50 determines that the PCV valve 27 is stuck at a certain opening degree and the process proceeds to step 270. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result of step 325 is negative, the one-opening intake air amount PCVGa1 becomes equal to or less than the predetermined value a1 and the predetermined value b1 or less, and the two-opening intake air amount PCVGa2 is larger than the predetermined value e1 or the predetermined value f1. Less than. Then, the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is located, for example, below a straight line f1-f1 (fixed determination) connecting “f1” and “f1” shown in FIG. It is considered that the change is linear on a straight line L16 (fixed) passing through the origin. In this case, it can be determined that the PCV valve 27 is stuck abnormally.

  According to the abnormality diagnosis device of the BGV device in this embodiment described above, the abnormality is diagnosed based on the one-opening intake air increase ΔPCVGa1 and the two-opening intake air increase ΔPCVGa2 as in the first abnormality diagnosis control in the first embodiment. Instead, the abnormality is diagnosed based on the intake air amount Ga (1 opening intake air amount PCVGa1, 2 opening intake air amount PCVGa2), which is the detection value (absolute value) of the air flow meter 51 as it is. Therefore, although the intake air amount Ga detected by the individual difference (variation) of the air flow meter 51 and the individual difference (variation) of the engine system varies, the diagnostic accuracy is slightly reduced, but the first abnormality diagnosis of the first embodiment is performed. It is possible to obtain substantially the same operation and effect as the control.

  In this embodiment, the 1-opening intake air amount PCVGa1 is compared with its own predetermined values a1, b1, and f1, and the 2-opening intake air amount PCVGa2 is compared with its own predetermined values c1, d1, e1, and f1. Therefore, the change in the intake air amount Ga when the PCV valve 27 is changed from the first opening OP1 to the second opening OP2 is properly confirmed. For this reason, the accuracy of the abnormality diagnosis of the BGV device can be improved.

  In this embodiment, the 1-opening intake air amount PCVGa1 is larger than the predetermined value a1 and the 2-opening intake air amount PCVGa2 is larger than the predetermined value c1. If the change is linear, it is determined that the BGV device is normal. In addition, the 1-opening intake air amount PCVGa1 is equal to or less than a predetermined value a1, the 2-opening intake air amount PCVGa2 is equal to or less than a predetermined value c1, and the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 is linear. When the target change occurs, it is determined that the BGV passage 26 has a perforated abnormality. Under these conditions, it is easy to determine whether there is a hole in the BGV passage 26 or not. In this sense, it is possible to diagnose a large or small hole abnormality in the BGV passage 26 with high accuracy and in a relatively short time.

  In this embodiment, when the 2-opening intake air amount PCVGa2 becomes equal to or less than the predetermined value c1 and the change from the 1-opening intake air amount PCVGa1 to the 2-opening intake air amount PCVGa2 changes in a curved manner, the BGV passage 26 is blocked. It is determined to be abnormal. Under such conditions, the clogging abnormality of the BGV passage 26 is easily determined. In this sense, it is possible to diagnose a large or small clogging abnormality in the BGV passage 26 with high accuracy and in a relatively short time.

<Fourth embodiment>
Next, a fourth embodiment embodying an abnormality diagnosis device for a BGV device according to the present invention will be described in detail with reference to the drawings.

  This embodiment differs from the above embodiments in the mechanical configuration of the BGV device and the content of the abnormality diagnosis control. FIG. 13 shows a schematic configuration diagram of the gasoline engine system of this embodiment. As shown in FIG. 13, the mechanical configuration of the BGV device of this embodiment includes a first passage 43, a second passage 44, a third passage 45, instead of the BGV passage 26 and the PCV valve 27 described above. A three-way switching valve 47, a PCV valve 48 and a check valve 49 are provided. The first passage 43 includes a first end 43a and a second end 43b, and the first end 43a communicates with the oil separator 24. The second passage 44 includes a first end 44a and a second end 44b, and the second end 44b communicates with the intake passage 15 (the intake manifold 31) downstream of the electronic throttle device 18. The third passage 45 includes a first end 45a and a second end 45b, and fresh air is introduced from the first end 45a. A first end 45 a of the third passage 45 communicates with the intake passage 15 between the air cleaner 16 and the electronic throttle device 18. Further, the fresh air introduction passage 28 is connected to the third passage 45. That is, the fresh air introduction passage 28 includes a first end 28a and a second end 28b. The first end 28a communicates with the middle of the third passage 45, and the second end 28b communicates with the head cover 14. The three-way switching valve 47 is provided between the second end 43b of the first passage 43, the first end 44a of the second passage 44, and the second end 45b of the third passage 45, and the second passage 44 The flow path is switched so as to selectively communicate the first end 44a of the first passage 43 with the second end 43b of the first passage 43 or the second end 45b of the third passage 45. The PCV valve 48 adjusts the flow rate of the gas flowing through the second passage 44.

  The three-way switching valve 47 is a well-known electric switching valve, and is electrically turned on so that the first end 44a of the second passage 44 communicates with the second end 43b of the first passage 43. Is switched, and the introduction of blow-by gas into the intake passage 15 downstream of the throttle valve 17 is permitted. Also, when the three-way switching valve 47 is electrically turned off, the flow path is switched such that the first end 44a of the second passage 44 communicates with the second end 45b of the third passage 45, The introduction of fresh air into the intake passage 15 downstream of the throttle valve 17 is allowed. The PCV valve 48 is a well-known electrically operated valve configured to have a variable opening. The check valve 49 is provided in the second passage 44 downstream of the PCV valve 48. The check valve 49 is configured to regulate the flow of gas from the intake passage 15 to the PCV valve 48 and allow the flow in the opposite direction. Here, the responsiveness of the open / close switching of the three-way switching valve 47 is generally faster than the responsiveness when the PCV valve 48 is closed from a predetermined opening degree to a fully closed state or when the PCV valve 48 is opened from a fully closed state to a predetermined opening degree. it is conceivable that. In this embodiment, the first passage 43 and the second passage 44 constitute a BGV passage, and the three-way switching valve 47 and the PCV valve 48 constitute a gas flow control means. A part of the third passage 45 constitutes a fresh air introduction passage 28.

  In this embodiment, the ECU 50 corresponds to an example of the abnormality diagnosis unit and the control unit of the present invention. In order to selectively flow blow-by gas or fresh air into the intake passage 15 downstream of the electronic throttle device 18 according to the operation state of the engine 1, the ECU 50 controls the three-way switching valve 47 according to the operation state of the engine 1. It is configured to control the PCV valve 48. A detailed description of this control is omitted here.

  Next, the fourth abnormality diagnosis control executed by the ECU 50 will be described. FIG. 14 is a flowchart showing the contents of the abnormality diagnosis control. The flowchart of FIG. 14 differs from the flowchart of FIG. 2 in that step 500 is provided between steps 110 and 120 in FIG.

  When the processing shifts to this routine, the ECU 50 executes the processing of step 100 and step 110, and executes the switching processing of the three-way switching valve 47 in step 500 when the determination result of step 110 is affirmative. FIG. 15 is a flowchart showing details of the contents of this processing.

  As shown in FIG. 15, in step 501, the ECU 50 determines whether a predetermined abnormality diagnosis condition is satisfied. Here, the ECU 50 determines whether the condition is satisfied, for example, on condition that “abnormality diagnosis is not completed” or “during deceleration / fuel cut”. If the determination result is affirmative, ECU 50 shifts the processing to step 502, and if the determination result is negative, shifts the processing to step 504.

  In step 502, the ECU 50 switches the three-way switching valve 47 from ON to OFF. Accordingly, the three-way switching valve 47 switches the flow path so that the first end 44a of the second passage 44 communicates with the second end 45b of the third passage 45 in order to flow fresh air into the intake passage 15. Can be

  Next, in step 503, the ECU 50 sets the three-way switching flag X3WAY to “0” and returns the processing to step 501.

  On the other hand, in step 504, after switching the three-way switching flag X3WAY to “0”, the ECU 50 determines whether “3 seconds” have elapsed. This “3 seconds” time is merely an example. The ECU 50 shifts the processing to step 505 if this judgment result is affirmative, and returns the processing to step 501 if this judgment result is negative.

  In step 505, the ECU 50 switches the three-way switching valve 47 from OFF to ON. Thereby, the three-way switching valve 47 switches the flow path so that the first end 44a of the second passage 44 communicates with the second end 43b of the first passage 43 in order to flow the blow-by gas into the intake passage 15. Can be

  Next, in step 506, the ECU 50 sets the three-way switching flag X3WAY to “1”, and returns the processing to step 501.

In the switching process of step 500 described above, the ECU 50 sets the intake passage 15 when the engine 1 is performing the deceleration fuel cut and the abnormality diagnosis condition is satisfied, that is, when the abnormality of the BGV device is diagnosed. The three-way switching valve 47 is controlled to flow fresh air without flowing blow-by gas.

  Thereafter, in FIG. 14, the ECU 50 proceeds from step 500 to step 120, and executes the processing of steps 120 to 340.

  According to the abnormality diagnosis device for a BGV device of this embodiment described above, the three-way switching valve 47 is controlled in accordance with the operating state of the engine 1, so that the first end 44 a of the second passage 44 becomes the first end 44 a. The second end 43b of the passage 43 or the second end 45b of the third passage 45 is selectively connected to the intake passage 15 (intake manifold 31) downstream of the electronic throttle device 18 (throttle valve 17). Fresh air is selectively washed away. Therefore, the introduction of blow-by gas and fresh air into the intake passage 15 can be selectively switched only by controlling one relatively responsive three-way switching valve 47. For this reason, the introduction of blow-by gas and the introduction of fresh air into the intake passage 15 can be switched to high response with a relatively simple configuration. In the BGV device, at least one abnormality among the first to third passages 43 to 45, the three-way switching valve 47, and the PCV valve 48 is diagnosed. For this reason, the same operational effects as in the first embodiment can be obtained for abnormality diagnosis of the BGV device.

  In this embodiment, as the BGV device, abnormality of the first passage 43, the third passage 45, the three-way switching valve 47, and the PCV valve 48 is diagnosed. At the time of this abnormality diagnosis, fresh air instead of blow-by gas flows into the intake passage 15 via the first and third passages 43 and 45. Therefore, the change in the flow rate of fresh air when the opening degree of the PCV valve 48 is changed from the first opening degree OP1 to the second opening degree OP2 is made larger than when the flow rate of the blow-by gas is changed. This makes it possible to improve the accuracy of diagnosing a perforated abnormality in the pipe (the first passage 43 and the third passage 45). Further, at the time of abnormality diagnosis, since the blow-by gas does not flow into the intake passage 15, the oil mist in the crankcase 4 does not flow into the intake passage 15 together with the blow-by gas. For this reason, the amount of oil removed from the crankcase 4 at the time of abnormality diagnosis can be reduced.

<Fifth embodiment>
Next, a fifth embodiment embodying the abnormality diagnosis device for a BGV device according to the present invention will be described in detail with reference to the drawings.

  This embodiment differs from the above embodiments in the mechanical configuration of the BGV device and the content of the abnormality diagnosis control. FIG. 16 shows a schematic configuration diagram of the gasoline engine system of this embodiment. As shown in FIG. 16, the mechanical configuration of the BGV device of this embodiment is such that a non-motorized, pressure-sensitive (spring-operated) PCV is used instead of a motorized PCV valve 27 configured to have a variable opening. It comprises a valve 29 and an electrically operated open / close valve 30 which can be simply opened and closed. The PCV valve 29 is provided in the BGV passage 26 near the oil separator 24. A bypass passage 32 is provided between the oil separator 24 and the BGV passage 26 so as to bypass the PCV valve 29. The on-off valve 30 is provided in the bypass passage 32. The on-off valve 30 is connected to the ECU 50, and the opening and closing of the valve are controlled by the ECU 50. The on-off valve 30 is configured to be closed when not energized (off) and open when energized (on). In this embodiment, the non-motorized PCV valve 29 and the on-off valve 30 constitute an example of the gas flow rate adjusting means of the present invention. Therefore, when the engine 1 is operating, the non-electrically driven PCV valve 29 opens and closes appropriately in response to the pressure acting on the BGV passage 26. Thus, the flow rate of the blow-by gas from the crankcase 4 to the intake passage 15 is adjusted. At this time, the blow-by gas that has passed only through the PCV valve 29 flows through the BGV passage 26 by closing the electric on-off valve 30. On the other hand, when the on-off valve 30 is opened, the blow-by gas that has passed through the on-off valve 30 flows through the bypass passage 32. Therefore, blow-by gas that has passed through both the PCV valve 29 and the on-off valve 30 flows into the intake passage 15. The flow rate of the blow-by gas at this time is larger than the flow rate of the blow-by gas when the on-off valve 30 is closed. That is, in this embodiment, by opening and closing the on-off valve 30, the blow-by gas having a small flow rate and the blow-by gas having a large flow rate selectively flow through the BGV passage 26.

  Next, the fifth abnormality diagnosis control executed by the ECU 50 will be described. FIG. 17 is a flowchart showing the contents of the abnormality diagnosis control. FIG. 18 is a graph showing fifth determination data used for abnormality diagnosis.

  When the process proceeds to the routine shown in FIG. 17, in step 600, ECU 50 determines whether abnormality diagnosis flag XOBD is “0”, that is, whether abnormality diagnosis has not been performed. The ECU 50 shifts the processing to step 610 when the result of this determination is affirmative, and returns the processing to step 600 when the result of this determination is negative.

  In step 610, the ECU 50 determines whether the deceleration fuel cut is being performed. The ECU 50 shifts the processing to step 620 if the result of this determination is affirmative, and returns the processing to step 600 if the result of this determination is negative.

  In step 620, the ECU 50 takes in the intake air amount Ga when the on-off valve 30 is in the closed (off) state based on the detection value of the air flow meter 51. The on-off valve 30 is in a closed state when not energized (off). At this time, a small flow of blow-by gas that has passed only through the PCV valve 29 can flow through the BGV passage 26.

  Next, at step 630, the ECU 50 sets the intake air amount Ga taken at step 620 as the valve-closing intake air amount PCVGaOFF. This valve-closed intake air amount PCVGaOFF corresponds to an example of the first intake air amount of the present invention.

  Next, in step 640, the ECU 50 opens (turns on) the on-off valve 30. Here, by opening the on-off valve 30, a large flow of blow-by gas that has passed through the PCV valve 29 and the on-off valve 30 flows through the BGV passage 26.

  Next, in step 650, the ECU 50 takes in the intake air amount Ga when the on-off valve 30 is opened (turned on) based on the detection value of the air flow meter 51.

  Next, at step 660, the ECU 50 sets the intake air amount Ga taken at step 650 as the valve-open intake air amount PCVGaON. This valve-open intake air amount PCVGaON corresponds to an example of the second intake air amount of the present invention.

  Next, in step 670, the ECU 50 calculates the difference between the valve-opening intake air amount PCVGaON and the valve-closing intake air amount PCVGaOFF as the valve-opening intake air increase ΔPCVGa. That is, the valve-closing intake air amount PCVGaOFF is used as the reference intake air amount, and the increase amount of the valve-opening intake air amount PCVGaON is calculated.

  Next, in step 680, the ECU 50 closes (turns off) the on-off valve 30. Thereafter, in step 690, the ECU 50 determines whether or not the valve-opening intake air increase ΔPCVGa is larger than a predetermined value G1. If the determination result is affirmative, ECU 50 shifts the processing to step 700, and if the determination result is negative, shifts the processing to step 720.

  In step 700, the ECU 50 determines that the flow rate of the blow-by gas and the pipe (BGV passage 26) are normal. The ECU 50 can store the normality determination in the memory.

  This determination will be described with reference to fifth determination data shown in FIG. In FIG. 18, the horizontal axis indicates the flow rate of the on-off valve 30 (the flow rate of the blow-by gas flowing through the on-off valve 30), and the vertical axis indicates the value of the valve-open intake increase ΔPCVGa. “(OPoff)” on the horizontal axis indicates the flow rate when the on-off valve 30 is closed (off), and “(OPon)” indicates the flow rate when the on-off valve 30 is open (on). . In this embodiment, (OPoff) is set to “0” for convenience. If the determination result of step 690 is affirmative, the valve-open intake increase ΔPCVGa is larger than the predetermined value G1, and therefore, in FIG. It is considered that it changes linearly like a passing straight line (thick line) L21 (normal). In this case, it can be determined that the flow rate of the blow-by gas and the pipe (BGV passage 26) are normal.

  Then, in step 710, the ECU 50 sets the abnormality diagnosis flag XOBD to “1”, and returns the processing to step 600.

  On the other hand, at step 720 after shifting from step 690, the ECU 50 determines whether or not the valve-opening intake air increase ΔPCVGa is larger than a predetermined value H1 (<G1). The ECU 50 shifts the processing to step 730 when this determination result is affirmative, and shifts the processing to step 740 when this determination result is negative.

  In step 730, the ECU 50 determines that there is an abnormality with a small hole (small hole) in the blow-by gas pipe (BGV passage 26), and shifts the processing to step 710. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result in step 720 is affirmative, the valve-open intake increase .DELTA.PCVGa is equal to or less than the predetermined value G1 and is larger than the predetermined value H1. It is considered that the value changes linearly as a straight line (broken line) L22 (small hole) passing through the origin above the broken line and below the broken line for small hole determination. In this case, it can be determined that the blow-by gas pipe (BGV passage 26) has a small hole abnormality.

  On the other hand, after shifting from step 720 to step 740, the ECU 50 determines whether or not the valve-opening intake air increase ΔPCVGa is larger than a predetermined value I1 (<H1). If the determination result is affirmative, ECU 50 shifts the processing to step 750, and if the determination result is negative, shifts the processing to step 760.

  In step 750, the ECU 50 determines that the blow-by gas pipe has a medium-sized hole (medium hole), and shifts the processing to step 710. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the determination result in step 740 is affirmative, the valve-open intake increase ΔPCVGa is equal to or less than the predetermined value H1 and is larger than the predetermined value I1, and therefore, in FIG. It is considered that the line changes linearly like a straight line (broken line) L23 (hole) passing through the origin below the broken line and below the broken line for the hole determination. In this case, it can be determined that the blow-by gas pipe (BGV passage 26) has a hole abnormality.

  On the other hand, in step 760, the ECU 50 determines that there is an abnormality in which the blow-by gas pipe has a large hole (large hole), and shifts the processing to step 710. The ECU 50 can store the abnormality determination in the memory or execute a predetermined notification operation.

  If the result of the determination in step 740 is negative, the valve-open intake increase ΔPCVGa is equal to or less than the predetermined value I1, and therefore, in FIG. 18, the valve-open intake increase ΔPCVGa passes through the origin below the broken line for large hole determination. It is considered that the value changes linearly like a straight line (broken line) L24 (large hole). In this case, it can be determined that the blow-by gas pipe (BGV passage 26) has a large hole abnormality.

  According to the abnormality diagnosis device for a BGV device in this embodiment described above, it is possible to obtain the same operational effects as those in the first embodiment. That is, in this embodiment, the difference between the valve-opening intake air amount PCVGaON detected when the on-off valve 30 is opened and the valve-closing intake air amount PCVGaOFF detected when the valve is closed (the valve-opening intake air increase ΔPCVGa) is calculated. It can be made relatively large. For this reason, it is possible to secure a change in the flow rate necessary for determining a perforated abnormality such as a large or small hole in the pipe (BGV passage 26) of the BGV device. As a result, it is possible to accurately diagnose a large or small perforated abnormality relating to the pipe (BGV passage 26). Further, in order to ensure the accuracy of the abnormality determination, it is not necessary to take time for the determination, and the abnormality diagnosis can be performed in a relatively short time.

  Further, in this embodiment, the gas flow rate adjusting means in the present invention for adjusting the blow-by gas flow rate is not a motorized PCV valve 27 having a variable opening, but a non-motorized pressure sensitive (spring-operated) type. It is composed of a PCV valve 29 and an electric open / close valve 30 that can be simply opened and closed. Therefore, the gas flow rate adjusting means can be configured at a lower cost as compared with the case where the PCV valve 27 is used.

<Sixth embodiment>
Next, a sixth embodiment embodying an abnormality diagnosis device for a BGV device according to the present invention will be described in detail with reference to the drawings.

  This embodiment differs from the fifth embodiment in the mechanical configuration of the BGV device. In the fifth embodiment, in order to diagnose the abnormality of the BGV device, the flow rate of the blow-by gas flowing through the BGV passage 26 is changed to a small flow rate and a large flow rate by opening and closing the on-off valve 30. . Therefore, when the flow rate of the blow-by gas becomes large, the amount of oil mist carried away from the crankcase 4 also increases, and as a result, engine oil consumption tends to increase. For this reason, there is a limit in improving the accuracy of abnormality diagnosis and reducing engine oil consumption. Therefore, the abnormality diagnosis device of this embodiment is designed to achieve both improvement in abnormality diagnosis accuracy and reduction in engine oil consumption.

  FIG. 19 shows a schematic configuration diagram of the gasoline engine system of this embodiment. As shown in FIG. 19, also in the BGV device of this embodiment, a non-electric pressure-sensitive (spring-actuated) PCV valve 29 is used instead of the electric PCV valve 27 configured to be variable in opening. An electric open / close valve 30 configured to simply open and close the valve is provided. The PCV valve 29 is provided in the BGV passage 26 near the oil separator 24. In addition, a communication passage 33 that connects the two passages 26 and 28 is provided between the BGV passage 26 and the fresh air introduction passage 28 near the intake passage 15. The on-off valve 30 is provided in the communication passage 33. The opening and closing of the on-off valve 30 is controlled by the ECU 50. In this embodiment, the PCV valve 29 corresponds to an example of the gas flow control valve of the present invention. Therefore, when the engine 1 is operating, the non-electrically driven PCV valve 29 opens and closes appropriately in response to the pressure acting on the BGV passage 26. Thus, the flow rate of the blow-by gas from the crankcase 4 to the intake passage 15 is adjusted. At this time, when the electric open / close valve 30 is closed, the blow-by gas that has passed through the PCV valve 29 flows through the BGV passage 26 as indicated by the black arrow in FIG. On the other hand, when the on-off valve 30 is opened, the blow-by gas that has passed through the PCV valve 29 flows through the BGV passage 26 as shown by a black arrow in FIG. As shown by a broken line arrow, a part of fresh air (shown by a white arrow) flowing through the fresh air introduction passage 28 flows into the intake passage 15 together with the blow-by gas. The blow-by gas flow rate at this time is substantially the same as the blow-by gas flow rate when the on-off valve 30 is closed.

  Also in this embodiment, the content of the fifth abnormality diagnosis control shown in FIG. 17 and the fifth determination data shown in FIG. 18 can be adopted for the abnormality diagnosis control. Also in this embodiment, the ECU 50 corresponds to an example of the abnormality diagnosis means of the present invention.

  Therefore, in this embodiment, the same operation and effect as those of the fifth embodiment can be obtained. In addition, in this embodiment, when the on-off valve 30 is opened, the flow rate of the blow-by gas flowing to the intake passage 15 does not increase, but the fresh air flowing through the fresh air introduction passage 28 instead of the blow-by gas is used as the intake passage. It will flow to 15. Therefore, even if the on-off valve 30 is opened, the flow rate of blow-by gas from the crankcase 4 does not increase, and the amount of oil mist carried away from the crankcase 4 does not increase. Therefore, it is possible to improve the accuracy of abnormality diagnosis and reduce engine oil consumption at the same time.

<Seventh embodiment>
Next, a seventh embodiment embodying an abnormality diagnosis device for a BGV device according to the present invention will be described in detail with reference to the drawings.

  This embodiment differs from the fifth embodiment in the mechanical configuration of the engine system and the BGV device. FIG. 20 shows a schematic configuration diagram of the gasoline engine system of this embodiment. As shown in FIG. 20, the gasoline engine system includes a known supercharger 36. The supercharger 36 connects the compressor 36 a provided in the intake passage 15 between the electronic throttle device 18 and the air flow meter 51, the turbine 36 b provided in the exhaust passage 23, and integrally rotates the compressor 36 a and the turbine 36 b. Rotating shaft 36c. A well-known intercooler 37 is provided in the intake passage 15 between the compressor 36a and the electronic throttle device 18.

  Also in the BGV device of this embodiment, a non-motorized, pressure-sensitive (spring-operated) PCV valve 29 and a valve that can be simply opened and closed are used instead of the motorized PCV valve 27 configured to have a variable opening. And a motor-operated on-off valve 30 configured as described above. The PCV valve 29 and the on-off valve 30 are provided on the head cover 14, respectively. The PCV valve 29 and the on-off valve 30 are connected in parallel to the BGV passage 26, respectively. That is, the PCV valve 29 provided on the head cover 14 and the on-off valve 30 are connected in parallel to the entrance side of the BGV passage 26. The exit side of the BGV passage 26 is connected to the surge tank 19. In this case, the blow-by gas accumulated in the crankcase 4 flows into the head cover 14 through the communication passage 2a, and flows from the head cover 14 to the surge tank 19 through the PCV valve 29, the on-off valve 30, and the BGV passage 26. Will be. The inlet side of the fresh air introduction passage 28 is connected to the intake passage 15 upstream of the compressor 36a. The opening and closing of the on-off valve 30 is controlled by the ECU 50. In this embodiment, the non-motorized PCV valve 29 and the on-off valve 30 constitute an example of the gas flow rate adjusting means of the present invention.

  Also in this embodiment, the content of the fifth abnormality diagnosis control shown in FIG. 17 and the fifth determination data shown in FIG. 18 can be adopted for the abnormality diagnosis control. Also in this embodiment, the ECU 50 corresponds to an example of the abnormality diagnosis means of the present invention.

  Therefore, in this embodiment, in the gasoline engine system including the supercharger 36, the same operation and effect as those of the fifth embodiment can be obtained.

  Note that the present invention is not limited to the above embodiments, and a part of the configuration can be appropriately changed and implemented without departing from the spirit of the invention.

  (1) In the first embodiment, the inlet of the BGV passage 26 is connected to the oil separator 24 provided in the crankcase 4. On the other hand, as shown in a schematic configuration diagram of the gasoline engine system in FIG. 21, an inlet of the BGV passage 26 may be connected to the head cover 14. In this case, the blow-by gas accumulated in the crankcase 4 flows into the head cover 14 via the communication passage 2a, and flows from the head cover 14 to the intake passage 15 via the BGV passage 26.

  (2) In the first to third embodiments, the PCV valve 27 is directly attached to the intake manifold 31, but the PCV valve may be connected to an intake passage (intake manifold) via a pipe such as a pipe.

  (3) In the second embodiment, similar to the first embodiment, the abnormality of the BGV device is diagnosed on the basis of the one-opening intake air increase ΔPCVGa1 and the two-opening intake air increase ΔPCVGa2. As in the embodiment, the BGV device may be configured to diagnose the abnormality of the BGV device based on the 1-opening intake air amount PCVGa1 and the 2-opening intake air amount PCVGa2.

  (4) In each of the above embodiments, the first intake air amount detected when the gas flow rate adjusting means is controlled to the first opening degree and the second intake air amount detected when the gas flow rate adjusting means is controlled to the second opening degree. An abnormality of the BGV reduction device is diagnosed based on the intake air amount. On the other hand, based on three or more detected intake air amounts corresponding to three or more opening degrees, a third intake air amount or the like detected when the gas flow rate adjusting means is controlled to the third opening degree or the like is added. A configuration for diagnosing an abnormality of the BGV device by using the method may be included in the gist of the present invention.

  (5) In the fifth to seventh embodiments, as a configuration for adjusting the flow rate of the blow-by gas, a non-motorized pressure-sensitive (spring-operated) PCV valve 29 and a valve that can be simply opened and closed. Although the electric open / close valve 30 configured as described above is provided, as the configuration for adjusting the blow-by gas flow rate, it is also possible to provide an electric PCV valve and an electric open / close valve configured to have a variable opening degree. it can.

  INDUSTRIAL APPLICATION This invention can be utilized for the BGV apparatus provided in a gasoline engine etc.

1 Engine 4 Crankcase (Blow-by gas storage)
14 Head cover (blow-by gas storage unit)
15 Intake passage 18 Electronic throttle device (intake amount adjusting means)
26 BGV passage (blow-by gas return passage)
27 PCV valve (gas flow control means)
29 PCV valve (gas flow control means, gas flow control valve)
30 On-off valve (gas flow control means)
32 Bypass passage (gas flow control means)
33 communication passage 43 first passage (blow-by gas return passage)
43a 1st end (entrance side)
43b 2nd end (exit side)
44 Second passage (blow-by gas return passage)
44a 1st end (entrance side)
44b 2nd end (exit side)
45 Third passage 45a First end (entrance side)
45b 2nd end (exit side)
46 Fourth passage 46a First end (entrance side)
46b 2nd end (exit side)
47 Three-way switching valve (gas flow control means)
48 PCV valve (gas flow control means)
50 ECU (abnormality diagnosis means, control means, air-fuel ratio calculation means)
51 air flow meter (intake air amount detection means)
56 oxygen sensor (air-fuel ratio calculation means)
Ga intake air amount OP0 zero opening degree OP1 first opening degree OP2 second opening degree PCVGa0 0 opening degree intake air amount (0th intake air amount)
PCVGa1 1 opening degree intake amount (first intake amount)
PCVGa22 2-opening intake air amount (second intake air amount)
ΔPCVGa1 1 opening degree intake increase (first intake increase)
ΔPCVGa2 2 opening degree intake increase (second intake increase)
a1 predetermined value (first predetermined value)
c1 predetermined value (second predetermined value)
A1 predetermined value (third predetermined value)
C1 predetermined value (fourth predetermined value)
PCVGaOFF Valve closing intake air amount PCVGaON Valve opening intake air amount ΔPCVGa Valve opening intake air amount increase

Claims (12)

An abnormality diagnosis device for diagnosing an abnormality of a blow-by gas reduction device for flowing blow-by gas generated in an engine to an intake passage and reducing the blow-by gas to the engine,
The engine is configured to generate a driving force in response to the supply of fuel and to shut off the supply of the fuel during deceleration,
The blow-by gas reducing device, a blow-by gas storage unit for storing blow-by gas generated in the engine, an intake air amount adjustment valve provided in the intake passage to adjust the amount of intake air flowing through the intake passage, A blow-by gas return passage for flowing the blow-by gas stored in the blow-by gas storage section to the intake passage downstream of the intake air amount control valve and returning the blow-by gas to the engine; and adjusting a blow-by gas flow rate in the blow-by gas return passage. Motor-driven gas flow rate adjustment means configured to be variable opening degree to
The abnormality diagnosis device includes an intake amount detection unit for detecting an intake amount in the intake passage upstream of the intake amount adjustment valve, and an abnormality diagnosis unit for diagnosing an abnormality of the blow-by gas reduction device. ,
The abnormality diagnosis means sets the gas flow rate adjustment means to a first opening degree and larger than the first opening degree at the time of deceleration of the engine and when the supply of the fuel to the engine is cut off. A first intake amount detected by the intake air amount detection means when controlling to the second opening degree and the first opening degree is controlled, and an intake air amount when controlling to the second opening degree An abnormality diagnosis device for the blow-by gas reduction device, wherein the abnormality of the blow-by gas reduction device is diagnosed based on the second intake air amount detected by the detection means.   The abnormality diagnosing means compares the first intake air amount with a first predetermined value, compares the second intake air amount with a second predetermined value larger than the first predetermined value, and compares the comparison results with each other. The abnormality diagnosis device for a blow-by gas reduction device according to claim 1, wherein the abnormality of the blow-by gas reduction device is diagnosed based on the abnormality.   The abnormality diagnosing means further controls the gas flow rate adjusting means to an opening degree of zero, and controls the first intake air quantity and the zero intake air quantity detected by the intake air quantity detecting means when the opening degree is controlled to zero. Is calculated as a first intake increase, a difference between the second intake amount and the zero intake amount is calculated as a second intake increase, and the first intake increase is determined as a third predetermined increase. Comparing the second intake air amount with a fourth predetermined value larger than the third predetermined value, and diagnosing an abnormality of the blow-by gas reducing device based on the comparison result. Item 2. An abnormality diagnosis device for a blow-by gas returning device according to Item 1.   The abnormality diagnosing means is configured such that the first intake air amount is larger than the first predetermined value, and the second air intake amount is larger than the second predetermined value, and the first air intake amount is calculated from the first air intake amount. When the change to the second intake air amount is a linear change, it is determined that the blow-by gas reducing device is normal, and the first intake air amount becomes equal to or less than the first predetermined value, and When the intake air amount of the second intake air amount becomes equal to or less than the second predetermined value and the change from the first intake air amount to the second intake air amount is a linear change, the blow-by gas return passage is abnormally perforated. The abnormality diagnosis device for a blow-by gas reduction device according to claim 2, wherein the abnormality diagnosis device determines that the condition is true.   The abnormality diagnosing means, when the second intake air amount is equal to or less than the second predetermined value and the change from the first intake air amount to the second intake air amount is a curve change, The abnormality diagnosis device for a blow-by gas reduction device according to claim 4, wherein it is determined that the blow-by gas reduction passage is clogged and abnormal.   The abnormality diagnosing means may be configured such that the first intake increase is larger than the third predetermined value, and the second intake increase is larger than the fourth predetermined value, and the first intake increase is determined from the first intake increase. When the change to the second intake increase is a linear change, it is determined that the blow-by gas reduction device is normal, and the first intake increase is equal to or less than the third predetermined value, and In the case where the intake air increase of No. 2 is equal to or less than the fourth predetermined value, and the change from the first intake air increase to the second intake air increase is a linear change, the blow-by gas return passage has an abnormal hole. The abnormality diagnosis device for the blow-by gas returning device according to claim 3, wherein the abnormality diagnosis device determines that the condition is true.   The abnormality diagnosing means is configured to determine whether the second intake increase is equal to or less than the fourth predetermined value and the change from the first intake increase to the second intake increase is a curve change. The abnormality diagnosis device for a blow-by gas reduction device according to claim 6, wherein it is determined that the blow-by gas reduction passage is clogged and abnormal. The abnormality diagnosis device further includes an air-fuel ratio calculation unit for calculating an air-fuel ratio in the engine,
The abnormality diagnosing means includes an abnormality diagnosis based on the intake air amount detected by the intake air amount detecting means, and an abnormality diagnosis of the blow-by gas reducing device based on a deviation from a reference value of an air-fuel ratio calculated by the air-fuel ratio calculating means. The abnormality diagnosis device for a blow-by gas reduction device according to any one of claims 1 to 7, wherein the abnormality is diagnosed.   9. The blow-by gas reducing device according to claim 1, wherein the gas flow rate adjusting means is a variable opening electric PCV valve directly attached to the pipe of the intake passage. Diagnostic device. The blow-by gas reduction device,
A first passage including a first end and a second end, wherein the first end communicates with the blow-by gas storage;
A second passage including a first end and a second end, wherein the second end communicates with the intake passage downstream of the intake amount control valve;
A third passage including a first end and a second end, and introducing fresh air from the first end;
The first end of the second passage, the first end of the second passage, and the second end of the third passage are provided between the second end of the first passage and the second end of the third passage. A three-way switching valve that is switched to selectively communicate with the second end of the first passage or the second end of the third passage;
An electric PCV valve configured to be variable in opening to adjust the flow rate of gas flowing through the second passage;
A control unit for controlling the three-way switching valve and the PCV valve, wherein the control unit transmits the blow-by gas or the new gas to the intake passage downstream of the intake air amount control valve in accordance with an operation state of the engine. Configured to control the three-way switching valve and the PCV valve in accordance with an operation state of the engine to selectively flow air,
9. The gas flow control device according to claim 1, wherein the first passage and the second passage constitute the blow-by gas returning passage, and the three-way switching valve and the PCV valve constitute the gas flow rate adjusting means. 10. An abnormality diagnosis device for the blow-by gas reduction device according to any one of the above.   The control means may connect the first end of the second passage to the third passage of the third passage so as to flow the fresh air into the intake passage when the abnormality of the blow-by gas reduction device is diagnosed. The abnormality diagnostic device for a blow-by gas reducing device according to claim 10, wherein the three-way switching valve is controlled so as to communicate with two ends. An abnormality diagnosis device for diagnosing an abnormality of a blow-by gas reduction device for flowing blow-by gas generated in an engine to an intake passage and reducing the blow-by gas to the engine,
The engine is configured to generate a driving force in response to the supply of fuel and to shut off the supply of the fuel during deceleration,
The blow-by gas reducing device, a blow-by gas storage unit for storing blow-by gas generated in the engine, an intake air amount adjustment valve provided in the intake passage to adjust the amount of intake air flowing through the intake passage, A blow-by gas return passage for flowing the blow-by gas stored in the blow-by gas storage section to the intake passage downstream of the intake air amount control valve and returning the blow-by gas to the engine; and adjusting a blow-by gas flow rate in the blow-by gas return passage. Gas flow control valve for performing, and a fresh air introduction passage for introducing fresh air to the blow-by gas accumulation unit,
The abnormality diagnosis device includes an intake amount detection unit configured to detect an intake amount in the intake passage upstream of the intake amount adjustment valve, the blow-by gas reduction passage downstream of the gas flow adjustment valve, and the fresh air introduction. A communication passage for communicating with the passage, an on-off valve provided in the communication passage,
Abnormality diagnosis means for diagnosing an abnormality of the blow-by gas reduction device,
The abnormality diagnosing means controls the closing and opening of the on-off valve when the engine is decelerated and when the supply of the fuel to the engine is shut off. Diagnosing an abnormality of the blow-by gas reduction device based on a valve closing intake amount detected by a detecting unit and a valve opening intake amount detected by the intake amount detecting unit when the valve opening control is performed. Diagnostic device for blow-by gas reduction device

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