JP4618009B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine having a plurality of cylinders, and more particularly to a control device for an internal combustion engine capable of calculating an intake air amount of each cylinder.

  There is known a device that estimates intake variation for each intake and calculates the intake amount of each cylinder (for example, see Patent Document 1). According to the apparatus of Patent Document 1, the intake characteristics of each cylinder are estimated from the air density in the intake manifold and the amount of air passing through the throttle, and the intake air amount is calculated based on the intake characteristics.

JP 2001-234798 A Japanese Unexamined Patent Application Publication No. 2004-1000047

  However, in the apparatus as described above, it is necessary to newly provide a sensor for detecting the air density, and there are problems of mounting property and cost increase. Furthermore, since parameters such as air density increase, the calculation load of the intake air amount increases.

  The present invention has been made to solve the above-described problems, and an object thereof is to easily calculate the intake air amount of each cylinder using an existing sensor.

In order to achieve the above object, a first invention is a control device for an internal combustion engine having a plurality of cylinders,
An intake sensor provided in an intake system of the internal combustion engine;
An intake timing specifying means for specifying an intake start timing and an intake end timing of each cylinder;
Output value integration means for integrating the output value of the intake sensor for each cylinder from the intake start timing to the intake end timing of each cylinder;
Intake air amount calculation means for calculating the intake air amount of each cylinder by averaging the integrated values for a predetermined cycle integrated by the output value integration means for each cylinder.

The second invention is a control device for an internal combustion engine having a plurality of cylinders,
An intake sensor provided in an intake system of the internal combustion engine;
An intake timing specifying means for specifying an intake start timing and an intake end timing of each cylinder;
Maximum value acquisition means for acquiring, for each cylinder, the maximum value of the output value of the intake sensor from the intake start timing to the intake end timing of each cylinder;
Intake air amount ratio calculating means for calculating an intake air amount ratio between cylinders by averaging the maximum value for a predetermined cycle acquired by the maximum value acquiring means for each cylinder. .

In a third aspect based on the second aspect, the intake timing specifying means includes output maximum timing specifying means for specifying a maximum output timing at which an output value of the intake sensor is maximized,
The maximum value acquisition unit acquires the output value of the intake sensor at the maximum output timing specified by the maximum output timing specification unit as a maximum value.

According to a fourth aspect of the present invention, in the first aspect of the invention, a fuel injection amount calculating means for calculating a fuel injection amount of each cylinder based on an output value of the intake sensor;
And a correction unit that corrects the fuel injection amount of each cylinder calculated by the fuel injection amount calculation unit based on the intake air amount of each cylinder calculated by the intake air amount calculation unit. To do.

According to a fifth invention, in the second or third invention, a fuel injection amount calculating means for calculating a fuel injection amount of each cylinder based on an output value of the intake sensor;
And a correction unit that corrects the fuel injection amount of each cylinder calculated by the fuel injection amount calculation unit based on the intake air amount ratio between the cylinders calculated by the intake air amount ratio calculation unit. Features.

According to a sixth aspect of the present invention, in the fourth or fifth aspect, torque estimation means for estimating an output torque of each cylinder based on the fuel injection amount of each cylinder corrected by the correction means;
Ignition timing changing means for retarding the ignition timing of other cylinders so as to be the same as the minimum value of the output torque of each cylinder estimated by the torque estimation means.

  Further, according to a seventh aspect of the present invention, in the first aspect, other cylinders have the same intake air amount of one cylinder among the intake air amounts calculated by the intake air amount calculation means. An air amount correcting means for correcting the intake air amount is further provided.

Further, an eighth invention is the seventh invention, wherein the catalyst provided in the exhaust passage of the internal combustion engine,
An exhaust fuel addition mechanism for adding fuel upstream of the catalyst;
A fuel addition amount calculating means for calculating a fuel addition amount added by the exhaust fuel addition mechanism so that an exhaust air fuel ratio upstream of the catalyst becomes a target air fuel ratio;
An exhaust timing specifying means for specifying the exhaust timing of each cylinder;
And an injection execution means for adding fuel from the exhaust fuel addition mechanism by the fuel injection amount calculated by the fuel addition amount calculation means at the exhaust timing specified by the exhaust timing specification means. .

A ninth invention is a control device for an internal combustion engine having a plurality of cylinders,
An intake sensor provided in an intake system of the internal combustion engine;
An intake timing specifying means for specifying an intake start timing and an intake end timing of each cylinder;
Output value integration means for integrating the output value of the intake sensor for each cylinder between the intake start timing and the intake end timing of each cylinder;
First intake air amount calculating means for calculating the intake air amount of each cylinder by averaging the integrated values for a predetermined cycle integrated by the output value integrating means for each cylinder;
An in-cylinder pressure sensor for detecting the in-cylinder pressure of each cylinder;
Second intake air amount calculating means for calculating a second intake air amount of each cylinder based on the in-cylinder pressure detected by the in-cylinder pressure sensor;
A deviation degree calculating means for calculating a deviation degree between the first intake air amount and the second intake air amount for each cylinder;
Intake sensor calibration means for calibrating the output value of the intake sensor when the degree of deviation is equal to or greater than a first predetermined value for all cylinders.

  In a tenth aspect based on the ninth aspect, when the degree of deviation is equal to or greater than a second predetermined value greater than the first predetermined value in all cylinders, it is determined that the intake sensor has failed. The apparatus further comprises intake sensor failure determination means.

  An eleventh aspect of the invention relates to an in-cylinder pressure sensor that calibrates the output value of the in-cylinder pressure sensor in the specific cylinder when the degree of divergence is a third predetermined value or more in the specific cylinder in the ninth or tenth aspect. It further comprises calibration means.

  In a twelfth aspect based on the eleventh aspect, when the degree of divergence is equal to or greater than a fourth predetermined value greater than the third predetermined value in the specific cylinder, the in-cylinder pressure sensor in the specific cylinder fails. In-cylinder pressure sensor failure determination means for determining that

  According to the first invention, the intake air amount of each cylinder can be calculated by integrating the output values of the air sensor and averaging the integrated values for a predetermined cycle. Here, the intake sensor is an existing sensor such as an air flow meter or a surge tank pressure sensor. Therefore, the intake air amount of each cylinder can be easily calculated using an existing sensor. Since it is not necessary to provide a new sensor, it is advantageous in terms of mountability and cost. Furthermore, by averaging the integrated values of a predetermined cycle, it is possible to sufficiently suppress the influence of noise in the output value of the intake sensor. For this reason, the intake air amount of each cylinder can be accurately calculated.

  According to the second invention, the maximum value of the output value of the air sensor is acquired, and the maximum value for a predetermined cycle is averaged, whereby the intake air amount ratio between the cylinders can be calculated. Here, the intake sensor is an existing sensor such as an air flow meter or a surge tank pressure sensor. Therefore, it is possible to easily calculate the intake air amount ratio between the cylinders using an existing sensor. Since it is not necessary to provide a new sensor, it is advantageous in terms of mounting cost. Furthermore, by averaging the maximum value of a predetermined cycle, it is possible to sufficiently suppress the influence of noise in the output value of the intake sensor. For this reason, the intake air amount ratio between the cylinders can be accurately calculated.

  According to the third invention, the calculation load can be further reduced by acquiring the output value of the intake sensor at the maximum output timing as the maximum value.

  According to the fourth invention, the fuel injection amount of each cylinder is corrected using the intake air amount of each cylinder calculated in the first invention. Thereby, since the air-fuel ratio of each cylinder can be made uniform, emission can be sufficiently suppressed.

  According to the fifth aspect, the fuel injection amount of each cylinder is corrected using the intake air amount ratio between the cylinders calculated in the second or third aspect. Thereby, since the air-fuel ratio of each cylinder can be made uniform, emission can be sufficiently suppressed.

  According to the sixth aspect, variation in output torque between the cylinders due to the difference in the fuel injection amount between the cylinders corrected in the fourth or fifth aspect can be suppressed by the retard control of the ignition timing.

  According to the seventh aspect, since the intake air amount of each cylinder can be made uniform, the variation in the air-fuel ratio of each cylinder can be sufficiently suppressed.

  According to the eighth aspect of the invention, the exhaust air / fuel ratio upstream of the catalyst can be accurately adjusted to the target air / fuel ratio.

  According to the ninth aspect, when the degree of deviation between the first intake air amount and the second intake air amount is equal to or greater than the first predetermined value in all the cylinders, the output value of the intake sensor is regarded as being shifted, The output value can be calibrated.

  According to the tenth aspect, when the divergence degree is equal to or greater than the second predetermined value in all the cylinders, it can be determined that the output value of the intake sensor has deviated significantly, and the intake sensor has failed.

  According to the eleventh aspect, when the degree of divergence is greater than or equal to the third predetermined value in the specific cylinder, it is considered that the output value of the in-cylinder pressure sensor in the specific cylinder is shifted, and the output value of the in-cylinder pressure sensor is calibrated. Can do.

  According to the twelfth invention, when the degree of divergence is greater than or equal to the fourth predetermined value in a specific cylinder, it is considered that the output value of the in-cylinder pressure sensor in the specific cylinder is significantly deviated, and the in-cylinder pressure sensor has failed. Can be determined.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
[Description of system configuration]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. As shown in FIG. 1, the system according to the first embodiment includes an internal combustion engine 1. The internal combustion engine 1 has a plurality of cylinders 2. FIG. 1 shows only one cylinder among a plurality of cylinders.

  The internal combustion engine 1 includes a cylinder block 6 having a piston 4 therein. The piston 4 is connected to the crankshaft 12 via a crank mechanism. A crank angle sensor 14 is provided in the vicinity of the crankshaft 12. The crank angle sensor 14 is configured to detect the rotation angle of the crankshaft 12. The cylinder block 6 is provided with a water temperature sensor 10. The water temperature sensor 10 is configured to detect the temperature of the cooling water circulating through the internal combustion engine 1.

  A cylinder head 8 is assembled to the upper part of the cylinder block 6. A space from the upper surface of the piston 4 to the cylinder head 8 forms a combustion chamber 16. The cylinder head 8 is provided with a spark plug 18 that ignites the air-fuel mixture in the combustion chamber 16. An in-cylinder pressure sensor 17 is provided in the vicinity of the combustion chamber 16. The in-cylinder pressure sensor 17 is configured to detect the pressure in the combustion chamber 16 (hereinafter referred to as “in-cylinder pressure”).

  The cylinder head 8 includes an intake port 20 that communicates with the combustion chamber 16. An intake valve 22 is provided at a connection portion between the intake port 20 and the combustion chamber 16. An intake passage 28 is connected to the intake port 20. An injector 26 for injecting fuel is provided in the vicinity of the intake port 20. A surge tank 30 is provided in the middle of the intake passage 28. The surge tank 30 is provided with a surge tank pressure sensor 31 that detects the pressure in the surge tank 30.

  A throttle valve 32 is provided upstream of the surge tank 30. The throttle valve 32 is an electronically controlled valve that is driven by a throttle motor 34. The throttle valve 32 is driven based on the accelerator opening AA detected by the accelerator opening sensor 38. In the vicinity of the throttle valve 32, a throttle opening sensor 36 is provided. The throttle opening sensor 36 is configured to detect the throttle opening TA. An air flow meter 40 is provided upstream of the throttle valve 32. The air flow meter 40 is configured to change an output value (output voltage) according to the amount of intake air. An air cleaner 42 is provided upstream of the air flow meter 40.

  The cylinder head 8 includes an exhaust port 44 that communicates with the combustion chamber 16. An exhaust valve 46 is provided at a connection portion between the exhaust port 44 and the combustion chamber 16. An exhaust passage 50 is connected to the exhaust port 44. A catalyst 54 is provided in the exhaust passage 50. An air-fuel ratio sensor 52 is provided upstream of the catalyst 54. An oxygen sensor 56 is provided downstream of the catalyst 54. The air-fuel ratio sensor 52 is configured to detect the exhaust air-fuel ratio. The oxygen sensor 56 is configured to invert the output according to the presence or absence of oxygen.

Further, the system of the present embodiment includes an ECU (Electronic Control Unit) 60 as a control device. The ECU 60 includes an averaging RAM (not shown). The averaging RAM is configured to store the calculated value or maximum value of the output value of the air flow meter 40 for a predetermined cycle.
An ignition plug 18, an injector 26, a throttle motor 34, and the like are connected to the output side of the ECU 60. On the input side of the ECU 60, a water temperature sensor 10, a crank angle sensor 14, an in-cylinder pressure sensor 17, a surge tank pressure sensor 31, a throttle opening sensor 36, an accelerator opening sensor 38, an air flow meter 40, an air-fuel ratio sensor 52, an oxygen A sensor 56 and the like are connected. The ECU 60 executes overall control of the internal combustion engine such as fuel injection control and ignition timing control based on the output of each sensor.
Further, the ECU 60 calculates the engine speed NE based on the output of the crank angle sensor 14.
Further, the ECU 60 calculates the engine load KL based on the accelerator opening AA detected by the accelerator opening sensor 38.

[Features of Embodiment 1]
According to the conventional device described above, the intake air amount of each cylinder is calculated based on the air density and the amount of air passing through the throttle. For this purpose, it is necessary to newly provide a sensor for detecting the air density, and there are problems with respect to mountability and cost.

In contrast, the system according to the first embodiment calculates the intake air amount of each cylinder using only the output of the existing air flow meter 40. As will be described below, in the first embodiment, the intake air amount of each cylinder is obtained by integrating the output values of the air flow meter 40 from the intake start timing to the intake end timing of each cylinder.
Here, when the intake valve 22 is opened and air is sucked into the combustion chamber 16 of the cylinder 2, the pressure in the surge tank 30 decreases. As a result, the amount of air passing through the throttle valve 32 increases. That is, the output of the air flow meter 40 fluctuates later than the actual intake stroke.

  FIG. 2 is a diagram illustrating a change in output of each sensor accompanying intake air. Specifically, FIG. 2 (A) shows the output waveform of the pressure sensor in the surge tank, FIG. 2 (B) shows the output waveform of the air flow meter, and FIG. 2 (C) shows the cylinder It is a figure which shows the output waveform of an internal pressure sensor. Here, in FIGS. 2A to 2C, the symbols “# 1”, “# 2”, “# 3”, and “# 4” are assigned to the first, second, third, and fourth cylinders, respectively. The corresponding waveform is shown. For the third cylinder (# 3), the intake air amount is forcibly decreased.

  When the intake valve 22 of the fourth cylinder (# 4) is opened, air flows from the intake passage 28 into the combustion chamber 16. As a result, the amount of air in the surge tank 30 decreases, so that the pressure in the surge tank 30 decreases as shown in FIG. Then, the amount of air passing through the throttle valve 32 and the air flow meter 40 increases. For this reason, the output of the air flow meter 40 increases as shown in FIG. Thereafter, when the fourth cylinder (# 4) shifts to the compression stroke, the in-cylinder pressure increases as shown in FIG.

  In the first embodiment, such characteristics are used to specify which cylinder the intake stroke is caused by the output of the air flow meter 40. Then, by integrating the output of the air flow meter 40 in the intake stroke of the specific cylinder, the intake air amount of the specific cylinder is calculated. Similarly, for each cylinder, the intake air amount of each cylinder is calculated by integrating the output of the air flow meter 40.

  Therefore, according to the first embodiment, it is possible to calculate the intake air amount of each cylinder using only the output of the existing air flow meter. Therefore, it is not necessary to add a new sensor, and it is not necessary to consider its mountability. Further, since there is no increase in parameters, an increase in calculation load can be prevented, and the intake air amount of each cylinder can be calculated easily.

Further, if the intake air amount of each cylinder is calculated using the output integrated value of the air flow meter 40 for only one cycle, the intake air amount may not be accurately calculated. This is because noise is superimposed when the output of the air flow meter 40 is taken into the ECU 60.
Therefore, in the first embodiment, the intake air amount of each cylinder is calculated by averaging the output integrated value of the air flow meter 40 for a predetermined cycle. FIG. 3 is a diagram for explaining averaging of the output integrated value of the air flow meter. As shown in FIG. 3, the influence of noise on the output waveform of the air flow meter is large before averaging. By averaging the output waveform for a predetermined cycle, the influence of noise on the output waveform can be reduced. Therefore, the intake air amount of each cylinder can be calculated with high accuracy.

[Specific Processing in Embodiment 1]
FIG. 4 is a flowchart showing a routine executed by the ECU 60 in the first embodiment.
According to the routine shown in FIG. 4, first, the engine speed NE and the crank angle are read (step 100). Here, the ECU 60 can calculate the engine speed NE based on the output of the crank angle sensor 14.

Next, referring to the maps shown in FIGS. 5 and 6, the intake start timing and the intake end timing of each cylinder according to the engine speed NE are specified (step 102). FIG. 5 is a diagram showing an example of a map used for specifying the intake start timing. FIG. 6 is a diagram illustrating an example of a map used for specifying the intake end time.
In the maps shown in FIGS. 5 and 6, the crank angle base intake start timing and intake end timing are determined in relation to the engine speed NE. In these maps, the intake start timing and the intake end timing are set earlier as the engine speed NE is higher. The difference between the intake start time and the intake end time corresponds to the intake stroke time. These maps are provided for each cylinder. Therefore, according to these maps, the intake start timing and the intake end timing are specified for all the cylinders.

  Next, the cylinder that is currently inhaled is specified from the crank angle (step 104). Then, it is determined whether or not the cylinder specified in step 104 is different from the previous cylinder (the cylinder specified last time), that is, whether or not the intake cylinder has been changed (step 106). If it is determined in step 106 that the intake cylinder has not been changed, the output value (that is, the air amount) of the air flow meter 40 is integrated (step 108). Then, this routine is finished once.

  On the other hand, if it is determined in step 106 that the intake cylinder has been changed, the integrated value of the cylinder before the change is stored in the averaging RAM (step 110). Then, the integrated value of the cylinder before the change is cleared (step 112). After clearing the integrated value, integration of the air flow meter output is started for the changed intake cylinder, that is, the cylinder that is currently inhaled (step 114).

Next, it is determined whether or not an integrated value for a predetermined cycle is stored in the averaging RAM (step 116). In this step 116, it is determined whether or not an integrated value for a predetermined cycle is stored for each cylinder. That is, it is determined whether or not an integrated value necessary for averaging is stored. Therefore, if the integrated value for a predetermined cycle is not stored even for one cylinder, “NO” is determined in step 116. If it is determined in step 116 that the accumulated value for the predetermined cycle has not been stored, this routine is once terminated.
Thereafter, when this routine is started again, the output value of the air flow meter 40 is integrated by the above method until the intake cylinder is changed (step 108). When the intake cylinder is changed, the integrated value of the cylinder before the change is stored in the averaging RAM (step 110). Subsequently, the determination process of step 116 is executed.

  If it is determined in step 116 that the accumulated value for the predetermined cycle is stored, the accumulated value for the predetermined cycle of each cylinder is averaged for each cylinder (step 118). This averaged integrated value becomes the intake air amount of each cylinder.

  As described above, according to the routine shown in FIG. 4, the intake air amount of each cylinder can be easily calculated by integrating the air flow meter output. Since the existing air flow meter 40 can be used, there is no need to provide a new sensor, which is advantageous in terms of mountability and cost. Furthermore, since the parameters used for calculating the intake air amount of each cylinder can be reduced, the calculation load on the ECU 60 can be reduced.

  By the way, in the system of the first embodiment, the output value of the air flow meter is integrated, but the output value of the surge tank pressure sensor may be integrated (the same applies to the second embodiment described later). Also in this case, an intake cylinder is identified by referring to a map of the intake start timing and the intake end timing, and the intake air amount of each cylinder is obtained by integrating the output value of the surge tank pressure sensor for the intake cylinder. be able to.

  In the first embodiment, the ECU 60 executes the process of step 102, so that the “intake timing specifying means” in the first invention executes the process of step 108. The “output value integrating means” executes the processing of step 118, thereby realizing the “intake air amount calculating means” in the first invention.

Embodiment 2. FIG.
[Description of system configuration]
The system according to the second embodiment of the present invention can be realized by causing the ECU 60 to execute a routine shown in FIG. 8 to be described later using the hardware configuration shown in FIG.

[Features of Embodiment 2]
In the first embodiment, the intake air amount of each cylinder is calculated by integrating the output of the air flow meter 40 corresponding to the intake stroke of each cylinder. It is necessary to store a large amount of data in the averaging RAM before the integrated value averaging process is performed.

  In the second embodiment, the maximum value of the output of the air flow meter 40 corresponding to the intake stroke of each cylinder is obtained to calculate the intake air amount ratio between the cylinders. Accordingly, it is possible to reduce the amount of data stored in the averaging RAM before the averaging process is performed. Therefore, the calculation load of the ECU 60 can be further reduced as compared with the first embodiment.

  Similarly to the first embodiment, when the intake air amount ratio between the cylinders is calculated using the maximum value of the output of the air flow meter 40 for only one cycle, the intake air amount ratio cannot be calculated due to the influence of noise. There is a case. Therefore, in the second embodiment, the intake air amount ratio between the cylinders is calculated by averaging the output maximum value of the air flow meter 40 for a predetermined cycle. FIG. 7 is a diagram for explaining averaging of the output maximum value of the air flow meter. As shown in FIG. 7, the influence of noise on the output maximum value of the air flow meter is large before averaging. By averaging the output maximum value for a predetermined cycle, the influence of noise on the output maximum value can be reduced. Therefore, the intake air amount ratio between the cylinders can be calculated with high accuracy.

[Specific Processing in Second Embodiment]
FIG. 8 is a flowchart showing a routine executed by the ECU 60 in the second embodiment.
According to the routine shown in FIG. 8, the processing up to step 106 is executed as in the first embodiment.

If it is determined in step 106 that the intake cylinder has not been changed, the current output value of the air flow meter 40 (hereinafter referred to as “current output value”) is the output of the air flow meter 40 held in the ECU 60. It is determined whether it is larger than the maximum value (step 120). If it is determined in step 120 that the current output value is larger than the maximum value, the maximum value is updated (step 122). That is, the current output value is held as the maximum value.
On the other hand, if it is determined in step 120 that the current output value is less than or equal to the maximum value, this routine ends.

  If it is determined in step 106 that the intake cylinder has been changed, the maximum value of the cylinder before the change is stored in the averaging RAM (step 124). Then, the maximum value of the cylinder before the change is cleared (step 126). After the maximum value is cleared, acquisition of the maximum value is started for the changed intake cylinder, that is, the cylinder that is currently inhaled (step 128).

Next, it is determined whether or not the maximum value for a predetermined cycle is stored in the averaging RAM (step 130). In step 130, it is determined whether or not a maximum value for a predetermined cycle is stored for each cylinder. That is, it is determined whether or not the maximum value necessary for averaging is stored. Therefore, if the maximum value for a predetermined cycle is not stored even for one cylinder, “NO” is determined in step 130. If it is determined in step 130 that the maximum value for a predetermined cycle has not been stored, this routine is once terminated.
Thereafter, when this routine is started again, the maximum value is updated by the above method until the intake cylinder is changed (step 122). When the intake cylinder is changed, the maximum value of the cylinder before the change is stored in the averaging RAM (step 124). Thereafter, the determination process of step 130 is executed.

  When it is determined in step 130 that the maximum value for the predetermined cycle is stored, the maximum value for the predetermined cycle of each cylinder is averaged for each cylinder (step 132). Thereby, the intake air amount ratio between the cylinders is calculated.

  As described above, according to the routine shown in FIG. 8, the intake air amount ratio between the cylinders can be easily calculated by obtaining the maximum value of the output of the air flow meter. Since the existing air flow meter 40 can be used, there is no need to provide a new sensor, which is advantageous in terms of mountability and cost. Furthermore, since the parameters used for calculating the intake air amount ratio between the cylinders can be reduced, the calculation load of the ECU 60 can be reduced. In the second embodiment, only the maximum value needs to be held before the averaging process. Therefore, the calculation load of the ECU 60 can be further reduced as compared with the first embodiment.

  By the way, in the system of the second embodiment, the maximum value of the output of the air flow meter is acquired by the arithmetic processing, but the maximum value may be acquired using a sample hold circuit. The sample hold circuit is configured to hold the maximum value of the sampled output of the air flow meter 40. This sample and hold circuit can be provided in the ECU 60.

  In the second embodiment, the current output value is compared with the maximum value until the intake cylinder is changed, but the output value at a specific time may be acquired as the maximum value. . That is, referring to a map in which the maximum output timing at which the airflow meter output is maximum is determined in relation to the engine speed, the maximum output timing is specified for each cylinder, and the airflow at the specified maximum output timing is determined. The meter output may be acquired as the maximum value.

  In the second embodiment, the ECU 60 executes the process of step 102, so that the “intake timing specifying means” in the second invention executes the process of step 122, and “ The “maximum value acquisition means” executes the processing of step 132, thereby realizing the “intake air amount ratio calculation means” in the second invention.

Embodiment 3 FIG.
The system according to the third embodiment of the present invention can be realized by causing the ECU 60 to execute a routine shown in FIG. 5 described later using the hardware configuration shown in FIG.

[Features of Embodiment 3]
If the intake air amount is different in each cylinder and the fuel injection amount is the same in all the cylinders, the air-fuel ratio varies between the cylinders. Here, in the system shown in FIG. 1, the air-fuel ratio sensor 52 upstream of the catalyst 54 detects the total exhaust air-fuel ratio and does not detect the exhaust air-fuel ratio for each cylinder. Therefore, it is difficult to suppress the variation in the air-fuel ratio among the cylinders only by the feedback control of the fuel injection amount using the exhaust air-fuel ratio detected by the air-fuel ratio sensor 52. As a result, there may occur a situation where the emission amount of unburned HC, CO ₂ or the like cannot be sufficiently suppressed.

  Therefore, in the third embodiment, the fuel injection amount of each cylinder is corrected based on the intake air amount of each cylinder. That is, the base injection amount of each cylinder calculated based on the total intake air amount detected by the air flow meter 40 is corrected based on the intake air amount of each cylinder. Thereby, since the air-fuel ratio of each cylinder can be made uniform, the dispersion | variation in the air-fuel ratio between cylinders can be suppressed. As a result, the emission amount of emissions can be sufficiently suppressed.

  Further, when the fuel injection amount is different among the cylinders, the output torque varies among the cylinders. Therefore, in the third embodiment, the output torque of each cylinder is estimated based on the intake air amount of each cylinder, that is, based on the fuel injection amount of each cylinder corrected as described above. Then, the ignition timing of the cylinder other than the cylinder having the smallest estimated output torque, that is, the cylinder having the smallest intake air amount is retarded. Thereby, since the output torque of the other cylinders can be reduced, the output torque of each cylinder can be made uniform. Therefore, torque variation between cylinders can be suppressed.

[Specific Processing in Embodiment 3]
FIG. 9 is a flowchart showing a routine executed by the ECU 60 in the third embodiment.
As shown in FIG. 9, first, the intake air amount and the engine speed NE are read (step 140). This intake air amount is not the intake air amount of each cylinder calculated in the first embodiment, but the intake air amount in the internal combustion engine as a whole.

  Next, the base fuel injection amount of each cylinder is calculated (step 142). Here, the ECU 60 sets the target air-fuel ratio in a routine different from this routine. In step 142, the base fuel injection amount of each cylinder is calculated from the set target air-fuel ratio and the intake air amount read in step 140.

  Then, the intake air amount of each cylinder corresponding to the engine speed NE read in step 140 is read (step 144). Here, the ECU 60 stores the intake air amount of each cylinder calculated by the routine shown in FIG. 4 of the first embodiment. In step 144, the stored intake air amount of each cylinder can be read out.

  Next, the base fuel injection amount of each cylinder is corrected based on the intake air amount of each cylinder read in step 144 (step 146). In step 146, the base fuel injection amount calculated in step 142 is increased or decreased. Thereby, the air-fuel ratio of each cylinder can be made the same as the target air-fuel ratio.

  Next, the output torque of each cylinder is estimated based on the intake air amount of each cylinder read in step 144 (step 148). Here, as the intake air amount increases, the fuel injection amount corrected in step 146 increases. Therefore, the estimated output torque increases as the intake air amount increases.

  Next, the ignition timing of each cylinder other than the cylinder with the smallest output torque is retarded with reference to a map stored in advance in ECU 60 (step 150). Here, the cylinder with the smallest intake air amount has the smallest output torque because the fuel injection amount becomes the smallest. Therefore, in step 150, the ignition timing is retarded for each cylinder other than the cylinder having the smallest intake air amount. In this map, the ignition timing is determined by the relationship between the engine speed and the output torque. According to the map, the greater the intake air amount, the greater the output torque, so that the ignition timing is greatly retarded. Therefore, the output torque of the other cylinders is suppressed so as to be the same as the output torque of the cylinder having the smallest intake air amount. For this reason, generation | occurrence | production of the torque variation between cylinders can be suppressed.

  As described above, according to the routine shown in FIG. 9, the variation in the air-fuel ratio among the cylinders can be suppressed by correcting the fuel injection amount of each cylinder based on the intake air amount of each cylinder. Furthermore, by delaying the ignition timing for a cylinder having a large output torque, variations in output torque among the cylinders can be suppressed.

  In the third embodiment, the intake air amount of each cylinder corresponding to the engine speed is read. However, the intake air amount of each cylinder corresponding to the engine load may be read. The ECU 60 can calculate the engine load based on the output of the accelerator opening sensor 38.

In the third embodiment, the fuel injection amount of each cylinder is corrected based on the intake air amount of each cylinder. However, based on the intake air amount ratio between the cylinders calculated in the second embodiment. The fuel injection amount of each cylinder may be corrected. Also in this case, since the air-fuel ratios of the cylinders can be made uniform, variations in the air-fuel ratio among the cylinders can be reduced.
Here, when the intake air amount ratio between the cylinders is constant regardless of the engine speed, there is no need to read the intake air amount ratio according to the engine speed. In this case, the fuel injection amount can be calculated based on the intake air amount ratio at any engine speed.

  In the third embodiment, the ECU 60 executes the process of step 142 so that the “fuel injection amount calculating means” in the fourth invention executes the process of step 146. By executing the process of step 148, the “correction means” causes the “torque estimation means” in the sixth invention, and by executing the process of step 150, the “ignition timing changing means” in the sixth invention respectively. It has been realized.

Embodiment 4 FIG.
[Description of system configuration]
FIG. 10 is a diagram for explaining a system configuration according to the fourth embodiment of the present invention. The system of the fourth embodiment further includes electromagnetically driven valve mechanisms 24 and 48 in addition to the system shown in FIG. The electromagnetically driven valve mechanisms 24 and 48 include two exciting coils (not shown). These exciting coils are connected to the output side of the ECU 60. The ECU 60 can change the operating characteristics (working angle and lift amount) of the intake valves 22 and 46 by supplying an exciting current to the exciting coil.

[Features of Embodiment 4]
According to the first embodiment, the intake air amount of each cylinder is calculated by integrating the output of the air flow meter 40. In the third embodiment, the air-fuel ratio of each cylinder is made uniform by correcting the fuel injection amount of each cylinder using the intake air amount of each cylinder. Further, by performing retard control of the ignition timing, variations in output torque between cylinders due to correction of the fuel injection amount are suppressed.

  In the fourth embodiment, the operation characteristics of the intake valve 22 are changed using the electromagnetically driven valve mechanism 24 based on the intake air amount of each cylinder. Thereby, since the intake air amount of each cylinder can be made uniform, the dispersion | variation in the intake air amount between cylinders can be suppressed. Therefore, the correction of the fuel injection amount and the retard control of the ignition timing as in the third embodiment are not required.

[Specific Processing in Embodiment 4]
FIG. 11 is a flowchart showing a routine executed by the ECU 60 in the fourth embodiment.
According to the routine shown in FIG. 11, first, the engine speed NE is read (step 152).
Next, the target lift amount of the intake valve 22 of each cylinder is calculated with reference to a map stored in advance in the ECU 60 (step 154). That is, the target control amount of the electromagnetically driven valve mechanism 24 is calculated. In the map, the target lift amount is set to increase as the engine speed NE increases.

  Next, the intake air amount of each cylinder corresponding to the engine speed NE read in step 152 is read (step 156). In step 156, similar to step 144 in the third embodiment, the intake air amount of each cylinder calculated by the routine shown in FIG. 4 is read.

  Next, the target lift amount of each cylinder is corrected using the intake air amount read in step 156 (step 158). Here, first, one specific cylinder is used as a reference. Then, the target lift amount of other cylinders is increased or decreased so as to be the same as the intake air amount of the specific cylinder. The larger the difference in intake air amount between the specific cylinder and the other cylinders, the larger the target lift amount is corrected. As a result, the target control amount of the electromagnetically driven valve mechanism 24 is corrected.

  As described above, according to the routine shown in FIG. 11, the variation in the intake air amount among the cylinders is reduced by correcting the lift amount of the intake valve of each cylinder based on the intake air amount of each cylinder. Can do. That is, by changing the operating characteristics of the intake valve 22 using the electromagnetically driven valve mechanism 24, the intake air amount of each cylinder is made uniform. Thereby, the dispersion | variation in the air fuel ratio between cylinders can be suppressed, without correcting the fuel injection amount. Furthermore, it is possible to suppress variations in output torque between cylinders without performing ignition timing retard control.

  In the fourth embodiment, the variation in intake air amount between cylinders is reduced by using an electromagnetically driven valve mechanism. However, the present invention is not limited to this, and by using a system having a variable valve mechanism and a variable valve timing mechanism. Also, the same effect as in the fourth embodiment can be obtained.

  By the way, an apparatus provided with an additional valve upstream of an intake valve is known (for example, refer to Japanese Patent No. 2612527). According to this device, the additional valve is opened when the intake valve is opened and the negative pressure in the combustion chamber increases, so that air can flow into the combustion chamber at a high speed. By using the system having the additional valve and correcting the valve opening timing of the additional valve based on the intake air amount of each cylinder, the flow velocity of air can be made different in each cylinder. As a result, the variation in the intake air amount between the cylinders can be reduced as in the fourth embodiment.

  In the fourth embodiment, the “air amount correcting means” according to the seventh aspect of the present invention is realized by the ECU 60 executing the process of step 158.

Embodiment 5 FIG.
[Description of system configuration]
The system according to the fifth embodiment of the present invention further includes an intake air temperature sensor (not shown) upstream of the throttle valve 32 in the system shown in FIG. This intake air temperature sensor is connected to the input side of the ECU 60.

[Features of Embodiment 5]
In the fourth embodiment, the variation in intake air amount between cylinders is suppressed by correcting the target lift amount of the intake valve based on the intake air amount of each cylinder and driving the variable valve mechanism 24. .

In the fifth embodiment, the variation in intake air amount between cylinders is suppressed by sequentially changing the opening of the throttle valve 32 (throttle opening TA). Here, the target value of the throttle opening degree TA can be calculated by a physical model of the intake system of the following equation (1) (see, for example, JP-A-2004-197608).
Mt = μ1 × At × {Pa / (√ (R × Ta))} × Φ (Pm / Pa) ・ ・ ・ (1)

  In the above equation (1), Mt represents the amount of air passing through the throttle valve (that is, the output of the air flow meter 40), μ1 represents the flow coefficient, and At represents the opening area of the throttle valve 40. Further, Pa is the pressure upstream of the throttle valve 40 (that is, atmospheric pressure or a correction thereof), R is a gas constant, Ta is the intake air temperature upstream of the throttle valve 40, Φ is a function, and Pm is the pressure downstream of the throttle valve 40. (That is, the target value of the surge tank pressure).

  As the intake air temperature Ta, the output of the intake air temperature sensor can be used. The target value of the surge tank pressure Pm can be obtained based on the rate of increase of the intake air amount (described later). Then, the opening area of the throttle valve 40 can be obtained from the obtained target value Pm and the above equation (1). The target value of the throttle opening TA can be calculated from the obtained opening area of the throttle valve 40.

[Specific Processing in Embodiment 5]
FIG. 12 is a flowchart showing a routine executed by the ECU 60 in the fifth embodiment.
According to the routine shown in FIG. 12, first, the engine speed NE is read. Further, the intake air amount of each cylinder corresponding to the engine speed NE is read (step 160). In step 160, the intake air amount of each cylinder calculated by the routine shown in FIG. 4 is read out as in step 144 of the third embodiment.

Next, a cylinder for increasing the intake air amount is specified (step 162). That is, a cylinder with a small intake air amount is specified. Then, an increase rate of the intake air amount of the cylinder specified in step 162 is calculated (step 164). The rate of increase can be calculated by the following formula (2).
Increase rate of intake air amount = (target intake air amount) / (intake air amount before increase) ... (2)

  Next, the target value of the surge tank pressure Pm is calculated with reference to the map shown in FIG. 13 (step 166). FIG. 13 is a diagram showing an example of a map used for calculating the target value of the surge tank pressure Pm. In this map, the target value of the surge tank pressure Pm is set to increase as the rate of increase of the intake air amount increases.

Next, the target throttle opening is calculated from the target value of the surge tank pressure Pm calculated in step 166 and the above equation (1) (step 168). Specifically, the opening area At of the throttle valve 32 is calculated by substituting the target value of the surge tank pressure Pm into the above equation (1), and the target throttle opening is calculated from the opening area At. Then, the opening degree of the throttle valve 32 is controlled to the target throttle opening degree.
By performing the above processing for the intake stroke of each cylinder, the throttle opening is sequentially changed.

  As described above, the intake air amount between the cylinders can be made uniform by sequentially changing the throttle opening in the intake stroke of each cylinder. Thereby, the dispersion | variation in the air fuel ratio between cylinders can be suppressed, without correcting the fuel injection amount. Furthermore, it is possible to suppress variations in output torque between cylinders without performing ignition timing retard control.

In the fifth embodiment, the target throttle opening is calculated using a physical model, but the target throttle opening may be calculated based on a map.
Specifically, first, the accelerator opening AA and the engine speed NE are read. Then, the base throttle opening corresponding to the accelerator opening AA is calculated. Next, the intake air amount of each cylinder corresponding to the engine speed NE is read out. Subsequently, a cylinder having a small intake air amount is specified, and a target intake air amount of the specified cylinder is calculated.
Next, a target throttle opening corresponding to the base throttle opening and the engine speed NE is calculated with reference to a map stored in advance in the ECU 60. That is, the base throttle opening degree in the intake stroke of the specified cylinder is corrected. In the map, the target throttle opening is set to increase as the base throttle opening increases. Further, the target throttle opening is set to be smaller as the engine speed NE is higher. This is because the sensitivity of the change in the intake air amount of each cylinder with respect to the change in the throttle opening becomes smaller as the base throttle opening becomes larger. Further, the higher the engine speed NE, the greater the sensitivity of the intake air amount change of each cylinder with respect to the throttle opening change.
Then, the throttle opening is controlled to the target throttle opening. Thereafter, the intake air amount of each cylinder is calculated, and when the deviation from the target intake air amount is large, the target throttle opening is calculated again by the above method.
Thus, the same effect as in the fifth embodiment can also be obtained by calculating the target throttle opening based on the map and sequentially changing the throttle opening in the intake stroke of each cylinder.

  In the fifth embodiment, the “air amount correction means” according to the seventh aspect of the present invention is realized by the ECU 60 executing the process of step 168.

Embodiment 6 FIG.
[Description of system configuration]
FIG. 14 is a diagram for explaining a system configuration according to the sixth embodiment of the present invention. The system of the sixth embodiment includes a NOx catalyst as the catalyst 54. The system of the sixth embodiment further includes an exhaust fuel addition injector 53 in addition to the system shown in FIG. The exhaust fuel addition injector 53 is configured to inject fuel into the exhaust passage 50 upstream of the NOx catalyst 54. The exhaust fuel addition injector 53 is connected to the output side of the ECU 60.

[Features of Embodiment 6]
In the above system, in order to reduce NOx occluded in the NOx catalyst 54 or to perform sulfur poisoning regeneration of the NOx catalyst 54, a fuel as a reducing agent is disposed upstream of the NOx catalyst 54 by the exhaust fuel addition injector 53. A so-called rich spike is added. In particular, it is known that the final target air-fuel ratio is narrow during sulfur poisoning regeneration of the NOx catalyst 54. Here, the final target air-fuel ratio refers to the final air-fuel ratio of the exhaust gas flowing into the NOx catalyst 54. This final target air-fuel ratio needs to be controlled in the range of, for example, 14.3 ± 0.1. This is because white smoke is emitted when it is biased to the rich side from this range, and the regeneration efficiency is lowered when it is biased to the lean side.

  Therefore, in the sixth embodiment, after correcting the lift amount of the intake valve 22 based on the intake air amount of each cylinder, the fuel addition amount by the exhaust fuel addition injector 53 is corrected. Thereby, the final target air-fuel ratio at the time of NOx reduction or sulfur poisoning regeneration can be accurately controlled. Therefore, especially sulfur poisoning regeneration can be performed stably.

[Specific Processing in Embodiment 6]
FIG. 15 is a flowchart showing a routine executed by the ECU 60 in the sixth embodiment.
According to the routine shown in FIG. 15, first, the intake air amount, the engine speed NE, and the accelerator opening AA are read (step 172).

Next, the base fuel injection amount of each cylinder is calculated from the intake air amount and the target air-fuel ratio (step 174).
Next, as in step 154 of the fourth embodiment, the target lift amount of the intake valve 22 of each cylinder is calculated (step 176). Then, as in step 156 of the fourth embodiment, the intake air amount of each cylinder corresponding to the engine speed NE read in step 172 is read (step 178).

  Next, similarly to step 158 of the fourth embodiment, the target lift amount of each cylinder is corrected using the intake air amount read in step 178 (step 180). Thereby, the intake air amount of each cylinder is made uniform.

  Next, the exhaust timing of each cylinder is specified according to the engine speed with reference to a map stored in advance in the ECU 60 (step 182). In this map, as in the maps shown in FIGS. 4 and 5, the crank angle-based exhaust timing is determined in relation to the engine speed NE. This map is provided for each cylinder. Therefore, in this step 182, the exhaust timing is specified for all the cylinders.

Next, the amount of added fuel at the exhaust timing of each cylinder is calculated (step 184). Here, first, the total fuel injection amount is calculated by the following equation (3). By substituting the calculated total fuel injection amount into the following equation (4), the exhaust added fuel amount is calculated. Here, the final target air-fuel ratio in the following equation (3) is the air-fuel ratio of the exhaust gas flowing into the NOx catalyst 52.
Total fuel injection amount = (intake air amount of specific cylinder) / final target air-fuel ratio (3)
Exhaust fuel amount = Total fuel injection amount-Photo fuel injection amount (4)

  Then, fuel is added by the exhaust fuel addition injector 53 at the exhaust timing specified in step 182 with the amount of exhaust addition fuel calculated in step 184 (step 186).

  As described above, according to the routine shown in FIG. 15, the exhaust air-fuel ratio discharged from each cylinder is substantially reduced by correcting the target lift amount of the intake valve 22 of each cylinder based on the intake air amount of each cylinder. Thus, the final target air-fuel ratio can be accurately controlled. For this reason, the air-fuel ratio control during NOx reduction and sulfur poisoning regeneration of the NOx catalyst 54 can be stably performed.

  In the sixth embodiment, when the ECU 60 executes the process of step 184, the “fuel addition amount calculating means” in the eighth invention executes the process of step 186. “Injection executing means” is realized.

Embodiment 7 FIG.
The system according to the seventh embodiment of the present invention can be realized by causing the ECU 60 to execute a routine shown in FIG. 16 to be described later using the hardware configuration shown in FIG.

[Features of Embodiment 7]
According to the first embodiment, the intake air amount of each cylinder is calculated. Further, the intake air amount of each cylinder can be calculated based on the output value of the in-cylinder pressure sensor by a known method. As an example, the intake air amount can be calculated based on the in-cylinder pressure and the in-cylinder volume (see, for example, JP-A-2005-36755).

  In the seventh embodiment, the intake air amount of each cylinder calculated using an air flow meter (hereinafter referred to as “first intake air amount”) and the intake air amount of each cylinder calculated using an in-cylinder pressure sensor. (Hereinafter referred to as “second intake air amount”), the air flow meter and the in-cylinder pressure sensor are calibrated.

  That is, when the difference between the first intake air amount and the second intake air amount exists in all cylinders in the same manner, it is determined that the output characteristics of the air flow meter are shifted. In this case, the output characteristics of the air flow meter are calibrated. Further, when this difference seen in all cylinders is remarkably large, that is, when the output characteristics of the air flow meter are exceeded, it is determined that the air flow meter has failed.

  Further, when the difference between the first intake air amount and the second intake air amount exists only in the specific cylinder, it is determined that the output characteristics of the in-cylinder pressure sensor of the specific cylinder are shifted. In this case, the output characteristic of the in-cylinder pressure sensor of the specific cylinder is calibrated. In addition, when this difference seen in the specific cylinder is remarkably large, that is, when the output characteristic of the in-cylinder pressure sensor exceeds the calibratable region, it is determined that the in-cylinder pressure sensor has failed.

  Therefore, according to the seventh embodiment, it is possible to accurately perform calibration and failure determination of the air flow meter and the in-cylinder pressure sensor using the intake air amount calculated in the first embodiment.

[Specific Processing in Embodiment 7]
FIG. 16 is a flowchart showing a routine executed by the ECU 60 in the seventh embodiment.
As shown in FIG. 16, first, the first intake air amount of each cylinder calculated based on the output value of the air flow meter 40 is read (step 188). Next, the second intake air amount of each cylinder calculated based on the output value of the in-cylinder pressure sensor 17 is read (step 190). Next, the degree of divergence between the first intake air amount and the second intake air amount is calculated for each cylinder (step 192).

  Next, it is determined whether or not the divergence degree of all the cylinders is equal to or greater than a predetermined value A (step 194). The predetermined value A is a reference value for determining whether or not the output characteristic deviation of the air flow meter 40 is within an allowable range. If it is determined in this step 194 that the degree of divergence of all the cylinders is greater than or equal to the predetermined value A, it is further determined whether or not the divergence of all the cylinders is greater than or equal to a predetermined value B greater than the predetermined value A (step 196). The predetermined value B is a reference value for determining whether or not output calibration of the air flow meter 40 is possible.

If it is determined in step 196 that the divergence degree of all the cylinders is equal to or greater than the predetermined value B, it is determined that the output of the air flow meter 40 is significantly deviated. In this case, it is determined that the air flow meter 40 has failed (step 198).
On the other hand, if it is determined in step 196 that the divergence degree of all the cylinders is smaller than the predetermined value B, it is determined that the output of the air flow meter 40 is deviated. In this case, the output of the air flow meter 40 is calibrated (step 200). In the output calibration of the air flow meter 40, the greater the deviation, the larger the calibration amount.

  On the other hand, if it is determined in step 194 that the divergence degree of all the cylinders is smaller than the predetermined value A, it is further determined whether or not the divergence degree of the specific cylinder is equal to or greater than the predetermined value C (step 202). The predetermined value C is a reference value for determining whether the output characteristic deviation of the in-cylinder pressure sensor 17 is within an allowable range. If it is determined in step 202 that the degree of deviation of the specific cylinder is greater than or equal to the predetermined value C, it is determined whether or not the degree of deviation of the specific cylinder is greater than or equal to a predetermined value D that is greater than the predetermined value C (step). 204). The predetermined value D is a reference value for determining whether or not output calibration of the in-cylinder pressure sensor 17 is possible.

If it is determined in step 204 that the degree of deviation of the specific cylinder is greater than or equal to the predetermined value D, it is determined that the output of the in-cylinder pressure sensor 17 of the specific cylinder is significantly deviated. In this case, it is determined that the in-cylinder pressure sensor 17 of the specific cylinder has failed (step 206).
On the other hand, if it is determined in step 204 that the degree of deviation of the specific cylinder is smaller than the predetermined value D, it is determined that the output of the in-cylinder pressure sensor 17 of the specific cylinder is deviated. In this case, the output of the in-cylinder pressure sensor 17 for the specific cylinder is calibrated (step 208). In the output calibration of the in-cylinder pressure sensor 17, the calibration amount is increased as the deviation degree is larger.

  As described above, according to the routine shown in FIG. 16, the air flow meter according to the degree of deviation between the intake air amount of each cylinder based on the air flow meter output and the intake air amount of each cylinder based on the in-cylinder pressure sensor output. 40 or the output calibration of the in-cylinder pressure sensor 17 or the failure determination of the air flow meter 40 or the in-cylinder pressure sensor 17 can be performed.

In the seventh embodiment, when the ECU 60 executes the process of step 188, the “first intake air amount calculating means” according to the ninth invention executes the process of step 190. The “second intake air amount calculating means” in the invention executes the processing of step 192, thereby realizing the “deviation degree calculating means” in the ninth invention.
In addition, the ECU 60 executes the process of step 200, the “intake sensor calibration means” in the ninth invention, and the process of step 198, the “intake sensor failure determination means” in the tenth invention By executing the processing in step 208, the “in-cylinder pressure sensor calibration means” in the eleventh invention is realized, and by executing the processing in step 206, the “in-cylinder pressure sensor failure determination means” in the twelfth invention is realized. ing.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a figure which shows the output change of each sensor accompanying inhalation. It is a figure for demonstrating averaging of the output integrated value of an air flow meter. 5 is a flowchart showing a routine that is executed by the ECU 60 in the first embodiment of the present invention. It is a figure which shows an example of the map used in order to specify an intake start time. It is a figure which shows an example of the map used in order to specify an intake end time. It is a figure for demonstrating averaging of the output maximum value of an airflow meter. In Embodiment 2 of this invention, it is a flowchart which shows the routine which ECU60 performs. In Embodiment 3 of this invention, it is a flowchart which shows the routine which ECU60 performs. It is a figure for demonstrating the system configuration | structure of Embodiment 4 of this invention. In Embodiment 4 of this invention, it is a flowchart which shows the routine which ECU60 performs. In Embodiment 5 of this invention, it is a flowchart which shows the routine which ECU60 performs. It is a figure which shows an example of the map used in order to calculate the target value of surge tank pressure Pm. It is a figure for demonstrating the system configuration | structure of Embodiment 6 of this invention. In Embodiment 6 of this invention, it is a flowchart which shows the routine which ECU60 performs. In Embodiment 7 of this invention, it is a flowchart which shows the routine which ECU60 performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 4 Piston 6 Cylinder block 8 Cylinder head 10 Water temperature sensor 12 Crankshaft 14 Crank angle sensor 16 Combustion chamber 17 In-cylinder pressure sensor 18 Spark plug 20 Intake port 22 Intake valve 24 Variable valve mechanism 26 Injector 28 Intake passage 30 Surge tank 32 Throttle valve 34 Throttle motor 36 Throttle opening sensor 38 Accelerator opening sensor 38
DESCRIPTION OF SYMBOLS 40 Air flow meter 42 Air cleaner 44 Exhaust port 46 Exhaust valve 48 Variable valve mechanism 50 Exhaust passage 52 Air fuel ratio sensor 53 Exhaust fuel addition injector 54 Catalyst 56 Oxygen sensor 60 ECU

Claims (4)

A control device for an internal combustion engine having a plurality of cylinders,
An intake sensor provided in an intake system of the internal combustion engine;
An intake timing specifying means for specifying an intake start timing and an intake end timing of each cylinder;
Output value integration means for integrating the output value of the intake sensor for each cylinder between the intake start timing and the intake end timing of each cylinder;
First intake air amount calculating means for calculating the intake air amount of each cylinder by averaging the integrated values for a predetermined cycle integrated by the output value integrating means for each cylinder;
An in-cylinder pressure sensor for detecting the in-cylinder pressure of each cylinder;
Second intake air amount calculating means for calculating a second intake air amount of each cylinder based on the in-cylinder pressure detected by the in-cylinder pressure sensor;
A deviation degree calculating means for calculating a deviation degree between the first intake air amount and the second intake air amount for each cylinder;
An internal combustion engine control device comprising: an intake sensor calibration unit that calibrates an output value of the intake sensor when the degree of deviation is equal to or greater than a first predetermined value for all cylinders. A control device for an internal combustion engine according to claim 1 ,
Intake sensor failure determination means for determining that the intake sensor has failed when the deviation degree is equal to or greater than a second predetermined value greater than the first predetermined value in all cylinders. Control device for internal combustion engine. The control device for an internal combustion engine according to claim 1 or 2 ,
A control apparatus for an internal combustion engine, further comprising an in-cylinder pressure sensor calibration unit that calibrates an output value of an in-cylinder pressure sensor in the specific cylinder when the degree of deviation is equal to or greater than a third predetermined value in the specific cylinder . A control device for an internal combustion engine according to claim 3 ,
In-cylinder pressure sensor failure determination means for determining that the in-cylinder pressure sensor in the specific cylinder has failed when the degree of divergence is equal to or greater than a fourth predetermined value greater than the third predetermined value in the specific cylinder. A control device for an internal combustion engine.

Images