JP3048531B2 - Method of diagnosing sensor failure in fuel injection device and device for diagnosing sensor failure in fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of diagnosing a failure of a sensor for detecting a rotation angle of a control shaft which is rotated to control a fuel injection amount in a so-called electronic control type fuel injection device. And the device,
In particular, the present invention relates to a failure diagnosis method and an apparatus for improving the reliability of diagnosis.

[0002]

2. Description of the Related Art As a so-called electronically controlled fuel injection control, for example, a control sleeve of a distribution type fuel injection pump is moved by a so-called electromagnetic actuator provided in the fuel injection pump. The amount of movement of the control sleeve is indirectly detected by detecting the rotation angle of a control shaft that connects between the electromagnetic actuator and the control sleeve by a sensor, and the sensor output signal is fed back to provide an electromagnetic actuator. There is a known and well-known device for controlling the rotation of the control shaft to a desired size (for example, see Japanese Patent Laid-Open No.
No. 203349). By the way, as a sensor for detecting the rotation angle of the control shaft, for example, a potentiometer is used. If the output of the sensor composed of a potentiometer always coincides with the actual rotation position of the control shaft, there will be no problem in the fuel injection control. May be different from the actual rotation position. If such a difference occurs, hunting and overrun of the engine may occur, and furthermore, the engine may stop.
As a measure to avoid such inconvenience, in the above-described fuel injection control, for example, a command value given to the above-described electromagnetic actuator to set the control shaft to a desired rotational position, that is, a target position When,
There is a sensor failure diagnosis method in which a comparison is made with a value detected by a sensor, and if the value does not exceed a predetermined upper limit or lower limit, the sensor is assumed to be normal and fuel injection control is performed. .

[0003]

However, in the case of a sensor using a potentiometer, for example,
If a liquid such as water enters the inside of the sensor due to some cause, a state equivalent to a short-circuit of a part of the potentiometer may occur, and a so-called rare short-circuit state in which an erroneous output value is obtained may occur. In such a case, as described above, simply determining whether or not the sensor has failed based on whether or not the sensor output value is within a predetermined range cannot be detected as a failure state. Therefore, there is a problem that normal injection control is not performed and the engine hunting, overrun, and engine stoppage are caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is capable of reliably preventing an engine abnormality caused by a failure of a sensor for detecting a rotational position of a control shaft used in an electronically controlled fuel injection device. An object of the present invention is to provide a method for diagnosing a sensor failure in an injection device and a device for diagnosing a sensor failure in a fuel injection device. It is another object of the present invention to reliably determine the presence or absence of a failure state of a sensor that detects a rotation position of a control shaft used in an electronically controlled fuel injection device, and to so-called engine upswing caused by the failure state of the sensor. It is an object of the present invention to provide a method for diagnosing sensor failure in a fuel injection device and a device for diagnosing sensor failure in a fuel injection device, which can reliably avoid the problem.

[0005]

According to a first aspect of the present invention, there is provided a method for diagnosing a sensor failure in a fuel injection device, wherein a rotation amount of a control shaft of a fuel injection pump for performing fuel injection to an internal combustion engine is detected by a rotation sensor. and a sensor failure diagnosis process in the fuel injection apparatus for diagnosing the presence or absence of a failure of the rotation sensor in the fuel injection device in which is configured to control the fuel injection amount based on the detected value, the engine speed Not more than the predetermined value, the amount of change in the engine speed is more than the predetermined value, and the engine is in the acceleration state, the accelerator pedal is not depressed, and the gear is in the neutral state. for 1, rather than the engine speed is above a predetermined value, the amount of change of the engine speed is equal to or greater than the predetermined value, moreover, a accelerating state, further Engine is a idling state, and, when the gear is in the neutral state of the second, when the case of any occurs, is made is configured to regard the failure of the rotation sensor.

[0006] In such a configuration, when the rotation sensor is in a condition of a so-called rare short-circuit, in particular, when the rotation sensor is in a so-called rare short state, the engine speed and the accelerator pedal are depressed from the viewpoint of preventing the engine from blowing up. Is set based on a combination of a plurality of conditions such as the presence or absence of a rotation sensor, and if the conditions are satisfied, it is regarded as a failure of the rotation sensor and safety is achieved. However,
When the engine brake is used, it is preferable from the viewpoint of safety to prevent the rotation sensor from being regarded as a failure of the rotation sensor.Therefore, the engine brake is used only when the gear is in a neutral state. This is characterized in that it is considered that the sensor is out of order and that it is a sensor failure.

According to a second aspect of the present invention, there is provided a method for diagnosing a sensor failure in a fuel injection system, wherein a rotation amount of a control shaft of a fuel injection pump for performing fuel injection to an internal combustion engine is detected by a rotation sensor, and the detected value is used as the detected value. A method for diagnosing a failure of the rotation sensor in a fuel injection device configured to control a fuel injection amount based on a fuel injection amount based on a fuel injection amount, wherein an engine speed is equal to or more than a predetermined value. Moreover, in a first state where a predetermined time has elapsed since the acceleration state and the accelerator pedal is not depressed, the engine speed is equal to or higher than the predetermined value, and In the second case where a predetermined time has elapsed since the start and the engine is idling, if the engine speed is equal to or more than a predetermined value,
And the change amount of the engine speed is equal to or more than a predetermined value,
Further, in a third state in which a predetermined time has elapsed since the acceleration state and the accelerator pedal is not depressed, the engine speed is not equal to or higher than the predetermined value, and the amount of change in the engine speed is Is greater than or equal to a predetermined value, and
A state where a predetermined time has elapsed since the acceleration state,
Further, when any one of the fourth cases in the idling state occurs, the rotation sensor is regarded as a failure.

[0008] In this configuration, when the rotation sensor is considered to be faulty, particularly when the rotation sensor is in a so-called rare short state, the engine speed or the accelerator pedal is depressed from the viewpoint of preventing the engine from blowing up. Is set based on a combination of a plurality of conditions such as the presence or absence of a rotation sensor, and if the conditions are satisfied, it is regarded as a failure of the rotation sensor and safety is achieved. However,
In the case where an engine brake is used, it is preferable from the viewpoint of safety to prevent the rotation sensor from being considered as a failure of the rotation sensor. The engine speed is equal to or greater than a predetermined value and a predetermined time has elapsed since the engine was accelerated, or the engine speed is equal to or greater than a predetermined value.
And not, have the amount of change in the engine rotational speed is equal to or higher than a predetermined value, it is determined that not the engine brake state is used, and it has the characteristics in that as regarded as sensor failure .

According to a third aspect of the present invention, there is provided a method for diagnosing a sensor failure in a fuel injection system, wherein the diagnostic condition according to the second aspect is added to the diagnostic condition according to the first aspect. When the diagnosis condition is satisfied, it is regarded as a sensor failure.

According to a fourth aspect of the present invention, there is provided a method for diagnosing a sensor failure in a fuel injection device, wherein when a failure of a rotation sensor is determined by the diagnostic method of the first, second or third aspect, the fuel injection amount is forcibly reduced. To zero.
As a result, it is possible to prevent the engine speed from inadvertently increasing and sudden acceleration or sudden start from occurring.

According to a fifth aspect of the present invention, there is provided a sensor failure diagnosis device for a fuel injection device, wherein a rotation amount of a control shaft of a fuel injection pump for injecting fuel into an internal combustion engine is detected by a rotation sensor, and the detected value is used as the detected value. A sensor failure diagnosis device for a fuel injection device configured to control a fuel injection amount based on the rotation of the rotation sensor in the fuel injection device, the engine failure detection device detecting an engine rotation speed Means, opening degree detecting means for detecting depression of an accelerator, idling detecting means for detecting an idling state, neutral detecting means for detecting a neutral state of a gear, the engine speed detecting means, the opening degree detecting means , based on an output signal of said idling detector and said neutral detecting means, engine Speed not less than the predetermined value, the amount of change of the engine speed is equal to or greater than the predetermined value, moreover, a accelerating state, further, a condition not stepped accelerator pedal and gear neutral In the first state, the engine speed is not equal to or higher than a predetermined value, the amount of change in the engine speed is equal to or higher than a predetermined value, the engine is in an accelerating state, the engine is in an idling state, and , The second case where the gear is in a neutral state, to determine whether any of the following cases has occurred,
Failure diagnosis means for determining that the rotation sensor has failed if it is determined that one of the two cases has occurred.

[0012] The failure diagnosis device having such a configuration realizes the sensor failure diagnosis method for the fuel injection device according to the first aspect described above.
It can be realized by executing a program by a so-called CPU.

According to a sixth aspect of the present invention, there is provided a sensor failure diagnosis device for a fuel injection device, wherein a rotation amount of a control shaft of a fuel injection pump for performing fuel injection to an internal combustion engine is detected by a rotation sensor, and the detected value is used as a detection value. A sensor failure diagnosis device for a fuel injection device configured to control a fuel injection amount based on the rotation of the rotation sensor in the fuel injection device, the engine failure detection device detecting an engine rotation speed Means, an opening degree detecting means for detecting depression of an accelerator, an idling detecting means for detecting a state of idling, and an engine speed detecting means, based on output signals of the opening degree detecting means and the idling detecting means, When the engine speed is equal to or higher than a predetermined value and a predetermined time In the first case where the accelerator pedal is not depressed, the engine speed is equal to or higher than a predetermined value, and a predetermined time has elapsed since the acceleration state, and the idling state In the second case, the engine speed is not equal to or greater than a predetermined value, the amount of change in engine speed is equal to or greater than a predetermined value, and a predetermined time has elapsed since the acceleration state, and In the third case where the accelerator pedal is not depressed, the engine speed is not equal to or higher than the predetermined value, the amount of change in the engine speed is equal to or higher than the predetermined value, and a predetermined time has elapsed since the acceleration state. State, and in the fourth case in the idling state, it is determined whether or not any of the cases has occurred. If it is determined that any of the four cases has occurred, the rotation sensor A failure diagnosis means regarded as disabled is made comprises a.

[0014] The failure diagnosis device having such a configuration realizes the sensor failure diagnosis method for the fuel injection device according to the second aspect described above.
It can be realized by executing a program by a so-called CPU.

According to a seventh aspect of the present invention, there is provided a sensor failure diagnosing device for a fuel injection device, which includes a diagnostic condition for a failure diagnosing device according to a fifth aspect of the present invention. A condition is added, and if any of the diagnostic conditions is satisfied, it is regarded as a sensor failure, and the accuracy of failure diagnosis is improved as compared with the device according to claim 5 or 6. is there.

According to an eighth aspect of the present invention, in the diagnostic apparatus of the fifth, sixth or seventh aspect, the fuel injection amount is forcibly set when the rotation sensor is regarded as having failed. This is provided with a means for preventing the air from being blown up to zero, whereby the engine speed is inadvertently increased and sudden acceleration or sudden start is prevented from occurring, and so-called fail safe is achieved. Is what it is.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. The members, arrangements, and the like described below do not limit the present invention, and can be variously modified within the scope of the present invention. First, the configuration of the sensor failure diagnosis device will be described with reference to FIG. The sensor failure diagnosis device according to the embodiment of the present invention includes a control unit 1 also used for fuel injection control, and a program (details described below) executed based on various information from various sensors and the like input to the control unit 1. (Described later). That is, the control unit 1 has a fuel injection control program stored therein in addition to a program for sensor failure diagnosis control as described later.
For example, an electromagnetic actuator 3 usually provided inside the distribution type fuel injection pump 2 and generally called an electronically controlled governor.
Alternatively, the operation of the fuel cut valve 4 is controlled.

The control unit 1 having such functions is realized, for example, by using a so-called well-known CPU as a main component. The storage of the program may be performed using a memory of the CPU, or may be performed using a so-called floppy disk. Of course, in this case, a known / known floppy disk drive is required. Further, the program may be stored in a hard disk and loaded into the CPU when the program is executed. Furthermore, a method using a magnetic tape may be used. When this magnetic tape is used, a known and well-known magnetic tape reader is required.

The control unit 1 receives a sensor output of a rotation sensor 5 provided in the distribution type fuel injection pump 2 and supplies the data to a fuel injection control and a sensor failure judgment control described later. It is supposed to be. The rotation sensor 5 detects a rotation position of a control shaft (not shown) of the fuel injection pump 2, and determines a fuel injection amount by detecting the rotation position of the control shaft. The position of a control sleeve (not shown) is detected. Further, the control unit 1 includes a vehicle speed sensor 6 for detecting a vehicle speed, an engine rotation sensor 7 for detecting an engine speed, an opening sensor 8 for detecting an accelerator opening, and sensor outputs of an idle switch 9 and a neutral switch 10. A so-called opening / closing signal is input. Here, the idle switch 9 is a switch that closes a contact when an accelerator pedal (not shown) is depressed, and detects an idling state. The neutral switch 10 is a switch that closes a contact when a gear (not shown) is in a neutral state, and detects that the gear is in a neutral state.

Next, the procedure of the sensor failure diagnosis process performed by the control unit 1 will be described with reference to the flowchart shown in FIG. When the processing is started, first, various data are read into the control unit 1, that is, the sensor output signals of the rotation sensor 5, the vehicle speed sensor 6, the engine rotation sensor 7, the opening degree sensor 8, and the idle switch. Each of the opening / closing signals of the neutral switch 9 and the neutral switch 10 is read (see step 100 in FIG. 2). Then, after reading the data, the first diagnostic processing is performed (see step 200 in FIG. 2). That is, in the embodiment of the present invention, the failure diagnosis of the rotation sensor 5 is roughly divided into two due to the difference in the diagnostic conditions and is sequentially executed. Step 200 is roughly divided into two. The sensor failure diagnosis is performed based on one of the diagnosis conditions (the details will be described later).

If it is determined as a result of the first diagnosis process that the condition for determining that the rotation sensor 5 is faulty is satisfied (in the case of YES), the blow-up prevention control (details will be described later). ) Is performed (see steps 300 and 600 in FIG. 2). On the other hand, when it is determined that the condition is not satisfied (in the case of NO), the second diagnosis processing is performed (step 300 in FIG. 2). , 400).

As a result of the second diagnosis processing, when it is determined that a condition that allows the rotation sensor 5 to be faulty is satisfied (in the case of YES), the same as in the first diagnosis processing described above. Then, the blow-up prevention control (details will be described later) is performed (see steps 500 and 600 in FIG. 2). On the other hand, if it is determined that the condition is not satisfied (NO),
It is determined that the rotation sensor 5 is not in a failure state, and a series of processings for failure diagnosis are ended, and the process returns to a main routine (not shown) to perform control for fuel injection control and the like.

On the other hand, after the start of the blow-up prevention control, it is determined whether or not the condition for the failure of the rotation sensor is not satisfied, in other words, whether or not the release condition is satisfied (see FIG. 2). If it is determined that the release condition is satisfied (YES), a release process (details will be described later) for releasing the previously started blow-up prevention control is performed (see step 800 in FIG. 2). ), A series of processing is ended.

Next, the specific contents of the first diagnosis process will be described with reference to the flowchart shown in FIG. When the first diagnosis process is started, first, it is determined whether or not the actual engine speed N is equal to or greater than a predetermined value Np (see step 202 in FIG. 3). In the case of YES), it is determined whether or not the accelerator pedal is depressed based on the opening / closing signal from the opening sensor 8 (see step 204 in FIG. 3). When it is determined that the gear is present (in the case of YES), it is subsequently determined whether the gear is in a neutral state (see step 206 in FIG. 3). Then, when it is determined that the sensor is in the neutral state (in the case of YES), the condition for the sensor failure state is satisfied (see step 208 in FIG. 3), and a series of processing is terminated, and the processing shown in FIG. Will return to the routine.

On the other hand, if it is determined in step 204 that the accelerator pedal is not being depressed in the determination of whether or not the accelerator pedal is being depressed (NO), it is determined that the vehicle is idling. It is determined based on the opening / closing signal of the idle switch 9 (see step 210 in FIG. 3), and when it is determined that the vehicle is idling (in the case of YES), the processing of step 206 described above is performed. It will go to. When it is determined that the vehicle is not in the idling state (in the case of NO), or
If it is determined in step 206 that the sensor is not in the neutral state (NO), it is determined that none of the conditions for the sensor failure state in the first diagnosis is satisfied (see step 216 in FIG. 3), and a series of steps is performed. The process will be terminated.

Further, when it is determined in the determination process in step 202 that the engine speed N is not equal to or more than the predetermined value Np (in the case of NO), the variation ΔN in the engine speed is equal to or more than the predetermined value ΔNp. It is determined whether or not (see step 212 in FIG. 3). here,
The change amount of the engine speed is a unit time (for example, 1 second)
The number of revolutions of the engine per hit, which is calculated from the actual number of engine revolutions detected by the engine revolution sensor 7. If it is determined that the difference is equal to or greater than the predetermined value ΔNp (in the case of YES), then it is determined whether the vehicle is in an acceleration state, in other words, whether the variation ΔN in the engine speed is a positive value (acceleration state). Or, a negative value (deceleration state) is determined (step 21 in FIG. 3).
4), when it is determined that the vehicle is in the acceleration state (in the case of YES), the process proceeds to step 204 described above, and thereafter, the above-described processing is performed. Also,
When it is determined in the previous step 212 that the amount of change ΔN in the engine speed is not equal to or greater than the predetermined value ΔNp (N
In the case of O), or when it is determined in step 214 that the vehicle is not in the accelerated state (in the case of NO), it is determined that none of the conditions for the sensor failure state in the first diagnosis processing is satisfied (see FIG. 3). A series of processes will be terminated.

After all, when the sensor failure state can be determined by the first failure diagnosis as described above, it can be classified into the following four cases. That is, first, the engine speed N is equal to or higher than the predetermined value Np, the accelerator pedal is not depressed, and the gear is in a neutral state. Second, the engine speed N is equal to or higher than a predetermined value Np, the engine is idling, and the gears are in a neutral state. Third, the engine speed must not exceed a predetermined value.
In this case, the amount of change ΔN of the engine speed is equal to or greater than a predetermined value ΔNp, the vehicle is in an accelerating state, the accelerator pedal is not depressed, and the gear is in a neutral state. . Fourth, engine speed
Is not greater than or equal to a predetermined value, the amount of change ΔN in the engine speed is greater than or equal to a predetermined value ΔNp, and the engine is in an accelerating state, the engine is in an idling state, and the gear is in a neutral state. is there.

As described above, in any one of these four states, the sensor is regarded as a sensor failure state, and the blow-up prevention control is performed (step 40 in FIG. 2).
0, 500, 600) means that the rotation sensor 5 is in a rare short state, that is, water or the like is inside the rotation sensor 5 for some reason in any of the above four states. If liquid invades and the output value is not an abnormal value that is considered to be a sensor failure, but a value that is different from the actual rotation angle of the control shaft is output, no countermeasures against failure are taken. If not, the fuel injection control is normally performed, and as a result, the engine speed further rises, so-called an engine blow-up state, and in the worst case, the engine burns out or breaks, etc. This is because it causes acceleration and may cause an undesirable situation in traffic safety. In particular, in the above four cases, one of the conditions that the gear is in a neutral state is one of the conditions to be satisfied. If the blow-up prevention control is performed, a dangerous condition may be created instead.
If the engine is not in the neutral state, the engine brake is used, and the engine blow-up prevention control is not performed without intentionally determining that the sensor has failed.

Next, the specific contents of the second diagnosis process will be described with reference to the flowchart shown in FIG. When the second diagnosis process is started, first, it is determined whether or not the actual engine speed N is equal to or more than a predetermined value Np (see step 402 in FIG. 4). In the case of NO), it is determined whether or not the amount of change ΔN in the engine speed is equal to or greater than a predetermined value ΔNp (see step 404 in FIG. 4), and if it is determined that it is equal to or greater than the predetermined value ΔNp (in the case of YES). Includes step 40 described below.
On the other hand, if it is determined that the value is less than the predetermined value ΔNp (NO), it is determined that the condition for the sensor failure state is not satisfied by the second diagnosis processing, and this series of processing ends. (Step 40 in FIG. 4)
4,416). Here, the amount of change in the engine speed is the same as that described in the first diagnosis process, and the description thereof will not be repeated here.

On the other hand, if it is determined in the previous step 402 that the engine speed N is equal to or greater than the predetermined value Np (in the case of YES), then it is determined whether or not the vehicle is accelerating, in other words, the change in the engine speed. Whether the amount ΔN is a positive value (acceleration state)
Alternatively, it is determined whether the value is a negative value (deceleration state) (see step 406 in FIG. 4). Then, when it is determined that the vehicle is in the accelerated state (in the case of YES), it is subsequently determined whether or not the elapsed time since the acceleration state is longer than a predetermined time (see step 408 in FIG. 4). ), When it is determined that the predetermined time has elapsed (in the case of YES)
Then, the process proceeds to step 410 described below. On the other hand, if the determinations in the previous steps 406 and 408 are both NO, it is determined that the condition for a sensor failure in the second failure diagnosis is not satisfied (see step 416 in FIG. 4). A series of processes is completed, and the process returns to the routine shown in FIG.

Next, in step 410, it is determined whether or not an accelerator pedal (not shown) is depressed based on the opening / closing signal from the opening degree switch 8 (see step 410 in FIG. 4). If it is determined that the step has not been performed (in the case of YES), it is determined that the condition for the sensor failure state has been satisfied (step 41 in FIG. 4).
4), a series of processing is completed. on the other hand,
In step 410, if it is determined that the accelerator pedal is not depressed, that is, if it is determined that the accelerator pedal is depressed (NO), then it is determined whether the engine is in the idling state by the idle switch. 9
(See step 412 in FIG. 4), and it is determined that the idle switch 9 is in the closed state, that is, in the idling state (YES).
In this case, the condition for the sensor failure is satisfied (see step 414 in FIG. 4), and the series of processes is terminated. If it is determined in step 412 that the vehicle is not in the idling state (NO), it is determined that the condition for the sensor failure state is not satisfied (see step 416 in FIG. 4), and a series of processing is terminated. Become.

After all, when the sensor failure state can be determined by the second failure diagnosis as described above, it can be classified into the following four cases. That is, first, a case where the engine speed N is equal to or higher than a predetermined value Np, a state where a predetermined time has elapsed since the acceleration state is reached, and the accelerator pedal is not depressed. . Second, a case where the engine speed N is equal to or higher than a predetermined value Np, a state where a predetermined time has elapsed since the acceleration state, and an idling state. Third, en
The engine rotation speed is not equal to or greater than a predetermined value, the engine speed change amount ΔN is equal to or greater than a predetermined value ΔNp, and a predetermined time has elapsed since the acceleration state; and
This is the case where the accelerator pedal is not depressed. Fourth, the engine speed is not equal to or greater than a predetermined value, the change amount ΔN of the engine speed is equal to or greater than a predetermined value ΔNp, and a predetermined time has elapsed since the acceleration state, and the engine is idling. It is in the state.

As described above, in any one of these four states, the sensor is regarded as a sensor failure state, and the blow-up prevention control is performed (step 40 in FIG. 2).
0, 500, 600) means that the rotation sensor 5 is in a rare short state, that is, water or the like is inside the rotation sensor 5 for some reason in any of the above four states. If liquid invades and the output value is not an abnormal value that is considered to be a sensor failure, but a value that is different from the actual rotation angle of the control shaft is output, no countermeasures against failure are taken. If not, the fuel injection control is normally performed, and as a result, the engine speed further rises, so-called an engine blow-up state, and in the worst case, the engine burns out or breaks, etc. This is because it causes acceleration and may cause an undesirable situation in traffic safety. In particular, in the above-described third case, one of the conditions that the amount of change in the engine speed is equal to or more than a predetermined value and the accelerator pedal is released is one of the conditions that is satisfied. If the amount is equal to or more than the predetermined value and the accelerator pedal is depressed, there is a possibility that the engine brake is being used, and in such a case, it is considered that the sensor is in a failure state and the engine blow-up prevention control is performed. Therefore, the engine brake is cut off, which may cause a dangerous state. Therefore, the engine brake use state is set so that the engine blow-up prevention control is not performed without intentionally determining that the sensor has failed.

Next, the specific contents of the blow-up prevention control (see step 600 in FIG. 2) will be described. This blow-up prevention control is based on the first diagnosis (step 20 in FIG. 2).
0) or the second diagnosis (see step 400 in FIG. 2)
In the case where it is determined that the condition is satisfied (see steps 300 and 500 in FIG. 2), the target fuel injection amount in the injection fuel control is set to zero and the fuel injection pump 2
To prevent fuel injection from being performed on an engine (not shown). As a result, the engine rotation is prevented from being increased more than necessary, so-called blow-up of the engine is prevented, and sudden acceleration and sudden start are prevented, and damage and damage to the engine are avoided.

Next, the details of the release condition (see step 700 in FIG. 2) will be specifically described. In the embodiment of the present invention, it is determined that the engine speed N is equal to or less than a predetermined value _NL. Or when it is detected that the depression of the accelerator pedal is equal to or more than a predetermined value and the idle switch 9 is off (in a case where the engine is not idling), it is determined that the release condition is satisfied. Is stopped (see step 600 in FIG. 2), and the state is returned to the normal fuel injection control state (see step 800 in FIG. 2).

In the example described above, the engine speed detecting means is provided by the engine speed sensor 7, the opening detecting means is provided by the opening sensor 8, the idling detecting means is provided by the idle switch 9, and the neutral detecting means is provided by the neutral switch. Each is realized by the switch 10. Further, the failure diagnosing unit executes the steps 100 to 500 (see FIG. 2) by the control unit 1, and the blow-up preventing unit executes the step 600 (see FIG. 2) by the control unit 1.
Each is realized.

Next, as a second example, a circuit example in which the above-described control is realized by a so-called logic circuit will be described with reference to FIGS. First, a description will be given of a logic circuit for generating a signal for starting the blow-up control with reference to FIG.
The first OR circuit 15 has a first AND circuit 16 and a second
The logical output of the AND circuit 17 is input, and the logical output of the first AND circuit 16 corresponds to the case where the condition is satisfied in the above-described first diagnostic processing. The logical output of the second AND circuit 17 corresponds to the case where the condition is satisfied in the above-described second diagnosis processing. First AND circuit 16
Has three inputs. The input stage receives the logical outputs of the second OR circuit 18 and the third OR circuit 19 and a logical signal S6 to be described later. Second O
The R circuit 18 has two inputs, and its input stage includes:
A logic signal S1 to be described later and a logic output of the third AND circuit 20 are input. In addition, the third A
The ND circuit 20 has two inputs, and its input stage receives logic signals S2 and S3 described later, respectively. The third OR circuit 19 has two inputs, and its input stage has a logic signal S described later.
4, S5, respectively.

On the other hand, the second AND circuit 17 has two inputs, and the logical output from the fourth and fifth OR circuits 21 and 22 is input to the input stage. The fourth OR circuit 21 has two inputs, and the logical output of the fourth and fifth AND circuits 23 and 24 is input to the input stage. The fourth AND circuit 23 has two inputs, and its input stage is configured to receive logic signals S1 and S7 to be described later. The fifth AND circuit 24 has two inputs, and its input stage has logic signals S2 and S described later.
7, respectively. Further, the fifth OR circuit 22 has two inputs, and the input stage receives the logic signals S4 and S5, respectively.

In this configuration, the logic signal S1 has a logic value H when the engine speed N is equal to or greater than a predetermined value Np.
and the logic signal S2 are the change amount Δ of the engine speed.
When N is equal to or more than the predetermined value ΔNp, the logical value is High, and the logical signal S3 is the logical value High when the amount of change ΔN in the engine speed is a positive value in the acceleration state, in other words, This is the signal. Therefore, the second
The logical output of the OR circuit 18 becomes High when the logical signal S1 becomes High or when the logical signal S1 becomes High.
2 and S3 are both High.

The logic signal S4 has a logic value High when the accelerator pedal is depressed, and the logic signal S5 has a logic value when the idle switch 9 is closed, in other words, when the engine is idling. High, respectively. Therefore, the logic output of the third OR circuit 19 becomes High because the logic signal S4 or S5
Becomes High. In addition,
The logic signal S6 is a signal having a logic value High when the gear is in a neutral state, and the logic signal S7 is
This signal is a logical value High when the vehicle is in an acceleration state and a predetermined time or more has elapsed since the acceleration state. From the above, the logical output of the first AND circuit 16 is Hi
gh is finally the following four cases. That is, first, the engine speed N is equal to or higher than the predetermined value Np, the accelerator pedal is not depressed, and the gear is in a neutral state. Second, the engine speed N is equal to or higher than a predetermined value Np, the engine is idling, and the gears are in a neutral state. Third, when the amount of change ΔN in the engine speed is equal to or greater than a predetermined value ΔNp, the vehicle is in an accelerating state, the accelerator pedal is not depressed, and the gear is in a neutral state. It is. Fourth, a case where the amount of change ΔN in the engine speed is equal to or greater than a predetermined value ΔNp, the vehicle is in an acceleration state, the engine is in an idling state, and the gear is in a neutral state.

On the other hand, the logical output of the fourth OR circuit 21 becomes the logical value High when the logical signals S1 and S7 have the logical value High or when the logical signals S2 and S7 have the logical value High. Become. Also, the fifth OR circuit 2
The logical output of the logical signal S2 becomes the logical value High because of the logical signal S
This is the case where either 4 or S5 has the logical value High. From the above, the logical output of the second AND circuit 17 is Hi
gh is finally the following four cases. That is, first, a case where the engine speed N is equal to or higher than a predetermined value Np, a state where a predetermined time has elapsed since the acceleration state is reached, and the accelerator pedal is not depressed. . Second, a case where the engine speed N is equal to or higher than a predetermined value Np, a state where a predetermined time has elapsed since the acceleration state, and an idling state. Third, the amount of change in engine speed Δ
This is a case where N is equal to or greater than a predetermined value ΔNp, a state where a predetermined time has elapsed since the acceleration state, and where the accelerator pedal is not depressed. Fourth,
This is a case where the change amount ΔN of the engine speed is equal to or greater than a predetermined value ΔNp, and a predetermined time has elapsed since the acceleration state, and the engine is in an idling state.

After all, the logical value Hig is applied to the first OR circuit 15.
When the signal of h is obtained, the above-described blow-up prevention control (see step 600 in FIG. 2) is started, so that the description will naturally be made with reference to FIGS. The same operation can be obtained by performing such processing by software.

Next, an example of a logic circuit for canceling the blow-up prevention control (see step 600 in FIG. 2) will be described with reference to FIG. This logic circuit realizes an operation corresponding to the processing of step 700 described in FIG. 2 and is a sixth OR circuit 25 having two inputs.
And a sixth AND circuit 26 having two inputs. The sixth OR circuit 26 receives a logic signal S8 described later and a logic output of the sixth AND circuit 26, while the sixth AND circuit 26 receives logic signals S9 and S10 described later. Is to be entered.

Here, the logic signal S8 is a signal which becomes a logic value High when the engine speed N becomes equal to or less than a predetermined value _NL , and the logic signal S9 is a signal which is obtained when the accelerator pedal is depressed by a predetermined value or more. Is a signal having a logical value High, and the logical signal S10 is a logical value High when the idle switch 9 is off (when not in the idling state).
gh. Therefore, the sixth OR circuit 2
The output of the signal for canceling the control for preventing the logical value High from being raised from the logical value High is performed when the engine speed N is equal to the predetermined value N.
_L , or when the accelerator pedal is depressed by a predetermined value or more and the idle switch 9 is turned off (when the vehicle is not in an idling state).

In the case of a vehicle having no idle switch 9, in the sensor failure diagnosis control described above, the fact that the vehicle is idling (see step 210 in FIG. 3 and step 412 in FIG. 4) is regarded as a sensor failure state. It does not need to be one of the conditions. In the control described above,
Although the first diagnostic process (see step 200 in FIG. 2) and the second diagnostic process (see step 400 in FIG. 2) are performed, only one of them may be performed to simplify the sensor failure diagnostic control. Things.

Next, another example of the sensor failure diagnosis apparatus will be described with reference to FIGS. First, the device configuration in this example is the same as that described above with reference to FIG. 1, and a detailed description thereof will be omitted, and a specific example of the sensor failure diagnosis process performed by the control unit 1 will be described. The contents will be described with reference to FIG. When the process is started, first, various data are read into the control unit 1, that is, the sensor output signals of the rotation sensor 5, the vehicle speed sensor 6, the engine rotation sensor 7 and the opening sensor 8, and the idle switch 9.
And the opening / closing signals of the neutral switch 10 are read (see step 900 in FIG. 7).

After reading the data, it is determined whether or not the vehicle speed is equal to or less than zero (see step 902 in FIG. 7). If it is determined that the vehicle speed is equal to or less than zero (YES), Fuel injection amount Q by fuel injection pump 2
There so that the whether less than a predetermined value Q _P is determined (FIG. 7
Step 904). If it is determined in step 904 that the fuel injection amount Q is equal to or _smaller than the predetermined value QP (Y
For ES), then the fuel injection amount Q is whether or not a predetermined time has elapsed from when a predetermined value or less Q _P is determined (see step 906 in FIG. 7), is determined to have passed a predetermined time or more that (in the case of YES), subsequently, the engine rotational speed N so that the whether more than a predetermined value N _P is determined (see step 908 of FIG. 7).

[0048] In step 908, the engine speed N is determined to be greater than a predetermined value _{N P} (the case of YES),
Next, (see step 910 in FIG. 7) The predetermined value N _P over state is determined whether or not the elapsed predetermined time, when it is determined that the elapsed predetermined time (YE
Then, it is determined whether or not the amount of change ΔN in engine speed is equal to or greater than a predetermined value ΔNp (see step 912 in FIG. 7). If it is determined that the amount of change ΔN in the engine speed is equal to or greater than the predetermined value ΔNp (in the case of YES), it is then determined whether or not the accelerator pedal is not depressed (FIG. 7). Step 9
14), when it is determined that the accelerator pedal has not been depressed (in the case of YES), it is determined whether or not the vehicle is idling (see step 916 in FIG. 7).

If it is determined in step 916 that the vehicle is idling (in the case of YES), it is determined that the rotation sensor 5 has failed, and a process for stopping the fuel injection control is performed (FIG. 9). Step 918 of 7,
920). That is, the operation of the electromagnetic actuator 3 of the fuel injection pump 2 is stopped (see step 918 in FIG. 7), the operation of the fuel cut valve 4 is stopped (see step 920 in FIG. 7), and the fuel injection is forcibly performed. It will be stopped and a series of processes will be ended. On the other hand, the previous steps 902, 904, 906, 90
In any of 8,910, 912, 914, and 916, if the determination result is NO, it is considered that the rotation sensor 5 is not a failure, a series of processing is ended, and the process returns to the main routine (not shown), and Will be performed.

In the above-described control, in particular, one of the conditions for determining that the vehicle speed is equal to or less than zero as a sensor failure is that in the operating state of the engine brake, other conditions excluding this vehicle speed include the rotation speed. This is because the above-described control is invalidated in the operating state of the engine brake, because the case may be satisfied even if the motion sensor 5 is actually normal. In the above control, the electromagnetic actuator 3
After the fuel cut valve 4 has been stopped, there is no so-called returnability for returning to a normal operation state when a specific condition is satisfied. When the engine key is turned on, the routine returns when the above conditions are not satisfied.

Next, a case where the above control is realized by a logic circuit will be described with reference to FIG. In the control described above, when the determination condition in each determination process is satisfied (YE
In the case of S), as can be understood from the fact that the operation of the electromagnetic actuator 3 and the fuel cut valve 4 is stopped, an AND circuit having six inputs as shown in FIG. 27 can be realized. Then, the logic signal Sa which is the input signal
Is the logical value High when the vehicle speed is equal to or lower than zero, the logical signal Sb becomes the logical value High when the injection amount is equal to or less than the predetermined value, and the state continues for a predetermined time or more, and the logical signal Sc indicates the engine speed. The number N is greater than or equal to a predetermined value Np;
If the state continues for a predetermined time or longer, the logical value is High.
It is what becomes. Further, the logic signal Sd becomes the logic value High when the variation ΔN of the engine speed is equal to or more than the predetermined value ΔNp, and the logic signal Se becomes the logic value High when the accelerator pedal is not depressed, and the logic signal Sd
f is a logical value High in the idling state. All of these logic signals have the logic value High.
, The output of the AND circuit 27 also has the logical value High.
The operation of the electromagnetic actuator 3 and the fuel cut valve 4 may be stopped by this signal.

In the case of a vehicle having no idle switch 9, it is not necessary to set the idling state (see step 916 in FIG. 7) as one of the conditions in the above-described control.

[0053]

As described above, according to the present invention, the use of the rotation sensor used for the fuel injection control of the fuel injection device in the failure state, particularly, in the fuel injection control in the so-called rare short state is described. Unlike the conventional configuration, it is possible to surely avoid an inadvertent rise of the engine, that is, a so-called blow-up caused by using the sensor output of the rotation sensor in the rare short state for the fuel injection control. Therefore, sudden start and sudden acceleration of the vehicle can be prevented, and engine breakage and damage due to overrun can be avoided, thereby contributing to improvement of traffic safety.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration example of a sensor failure diagnosis device in a fuel injection device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a procedure of sensor failure diagnosis control according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a procedure of a first diagnosis process.

FIG. 4 is a flowchart illustrating a procedure of a second diagnosis process.

FIG. 5 is a circuit diagram showing an example of a circuit configuration in a case where the contents of the first diagnostic processing and the second diagnostic processing shown in FIG. 3 are realized by a logic circuit;

FIG. 6 is a circuit diagram showing an example of a circuit configuration in a case where a process for determining whether a cancellation condition shown in step 700 of FIG. 2 is satisfied is realized by a logic circuit;

FIG. 7 is a flowchart showing a procedure in another example of sensor failure diagnosis control.

8 is a circuit diagram showing a circuit configuration example for implementing the sensor failure diagnosis control shown in FIG. 7 by a logic circuit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 control unit 2 fuel injection pump 3 electromagnetic actuator 4 fuel cut valve 5 rotation sensor 6 vehicle speed sensor 7 engine rotation sensor 8 opening sensor 9 idle switch 10 neutral switch

Continuation of the front page (51) Int.Cl. ⁷ identification code FI G01M 15/00 G01M 15/00 Z G05B 23/02 302 G05B 23/02 302R (58) Field surveyed (Int.Cl. ⁷ , DB name) F02D 41/22 F02B 77/08 F02D 45/00 F02M 41/12 F02M 65/00 G01M 15/00 G05B 23/02

Claims (8)

(57) [Claims] A fuel injection device configured to detect a rotation amount of a control shaft of a fuel injection pump for performing fuel injection to an internal combustion engine by a rotation sensor, and to control the fuel injection amount based on the detected value. A method for diagnosing a failure of the rotation sensor in the fuel injection device for diagnosing the presence or absence of a failure in the rotation sensor, wherein the engine speed is not equal to or greater than a predetermined value, and the variation in the engine speed is equal to or greater than a predetermined value, In the acceleration state, the accelerator pedal is not depressed, and the gear is in the first neutral state, the engine speed is not equal to or higher than a predetermined value, and the amount of change in the engine speed is predetermined. The engine is in an idling state,
And a second case in which the gear is in a neutral state. When any of the following cases occurs, it is considered that the rotation sensor has failed. 2. A fuel injection device configured to detect an amount of rotation of a control shaft of a fuel injection pump for injecting fuel into an internal combustion engine by a rotation sensor and to control the amount of fuel injection based on the detected value. A method for diagnosing a failure of the rotation sensor in the fuel injection device, wherein the engine speed is equal to or higher than a predetermined value and a predetermined time has elapsed since the acceleration state. And
In the first case where the accelerator pedal is not depressed, the engine speed is equal to or higher than a predetermined value, and a predetermined time has elapsed since the acceleration state, and
In the second case in the idling state, the engine speed is not equal to or higher than the predetermined value, the amount of change in the engine speed is equal to or higher than the predetermined value, and moreover, a predetermined time has elapsed since the acceleration state, In the third case where the accelerator pedal is not depressed, the engine speed is not equal to or higher than the predetermined value, the change amount of the engine speed is equal to or higher than the predetermined value, and the engine is in the acceleration state for a predetermined time. In a fourth case where the elapsed time has elapsed and the vehicle is in an idling state, a failure of the rotation sensor is regarded as a failure when any of the following cases occurs. . 3. In addition to the two cases in which the rotation sensor is regarded as malfunctioning according to claim 1, the engine speed is equal to or higher than a predetermined value, and a predetermined time has elapsed since the acceleration state. State, and
In a third case where the accelerator pedal is not depressed, the engine speed is equal to or higher than a predetermined value, and a predetermined time has elapsed since the acceleration state, and
In a fourth case in the idling state, the engine speed is not equal to or higher than the predetermined value, the amount of change in the engine speed is equal to or higher than the predetermined value, and a predetermined time has elapsed since the acceleration state. In the fifth case in which the accelerator pedal is not depressed, the engine speed is not equal to or greater than the predetermined value, the amount of change in the engine speed is equal to or greater than the predetermined value, and a predetermined time has elapsed since the acceleration state. In a sixth case where the elapsed time has elapsed and the vehicle is in the idling state, a failure of the rotation sensor is considered as a failure of the rotation sensor when any of the following cases occurs. 4. The sensor failure diagnosis method according to claim 1, wherein the fuel injection amount is forcibly reduced to zero when the rotation sensor is regarded as having failed. 5. A fuel injection device configured to detect an amount of rotation of a control shaft of a fuel injection pump for injecting fuel into an internal combustion engine by a rotation sensor and to control the amount of fuel injection based on the detected value. A sensor failure diagnosis device for a fuel injection device for diagnosing the presence or absence of a failure of the rotation sensor in (1), wherein an engine speed detection means for detecting an engine speed, an opening degree detection means for detecting depression of an accelerator, and idling. Idle detection means for detecting the state of the engine, neutral detection means for detecting the neutral state of the gear, and output signals from the engine speed detection means, the opening degree detection means, the idling detection means, and the neutral detection means. , rather than the engine speed is higher than a predetermined value, the predetermined value is the amount of change of the engine speed than A is, moreover, an accelerating state, further, a condition not stepped accelerator pedal, and, when the gear is first neutral state, rather than the engine speed is higher than a predetermined value, the engine rotation When the amount of change in the number is equal to or more than a predetermined value, and is in an accelerating state, and the engine is in an idling state,
And a second case in which the gear is in a neutral state. A failure diagnosis in which it is determined whether any of the following cases has occurred, and when it is determined that any of the two cases has occurred, it is regarded as a failure of the rotation sensor. Means for diagnosing a sensor failure in a fuel injection device, comprising: 6. A fuel injection device configured to detect an amount of rotation of a control shaft of a fuel injection pump for injecting fuel into an internal combustion engine by a rotation sensor and to control the amount of fuel injection based on the detected value. A sensor failure diagnosis device for a fuel injection device for diagnosing the presence or absence of a failure of the rotation sensor in (1), wherein an engine speed detection means for detecting an engine speed, an opening degree detection means for detecting depression of an accelerator, and idling. Idling detection means for detecting the state of the engine speed, based on the output signal of the engine speed detection means, the opening degree detection means and the idling detection means, the engine speed is equal to or more than a predetermined value, and moreover, the acceleration state A predetermined time has passed since
In the first case where the accelerator pedal is not depressed, the engine speed is equal to or higher than a predetermined value, and a predetermined time has elapsed since the acceleration state, and
In the second case in the idling state, the engine speed is not equal to or higher than the predetermined value, the amount of change in the engine speed is equal to or higher than the predetermined value, and moreover, a predetermined time has elapsed since the acceleration state, In the third case where the accelerator pedal is not depressed, the engine speed is not equal to or higher than the predetermined value, the change amount of the engine speed is equal to or higher than the predetermined value, and the engine is in the acceleration state for a predetermined time. In a fourth case in which the state has elapsed and the vehicle is idling, it is determined whether any of the following cases has occurred. If it is determined that any of the four cases has occurred, the rotation sensor And a failure diagnosing means which regards the failure as a failure of the fuel injection device. 7. The failure diagnosing means may further include a state in which the engine speed is equal to or higher than a predetermined value, a state in which a predetermined time has elapsed since the acceleration state, and an accelerator pedal is not depressed. The third
In the case of, the engine speed is equal to or higher than a predetermined value, and a predetermined time has elapsed since the acceleration state, and
In a fourth case in the idling state, the engine speed is not equal to or higher than the predetermined value, the amount of change in the engine speed is equal to or higher than the predetermined value, and a predetermined time has elapsed since the acceleration state. In the fifth case in which the accelerator pedal is not depressed, the engine speed is not equal to or greater than the predetermined value, the amount of change in the engine speed is equal to or greater than the predetermined value, and a predetermined time has elapsed since the acceleration state. In a sixth case in which the state has elapsed and the vehicle is in the idling state, it is determined whether any of the following cases has occurred. If it is determined that any of the six cases has occurred, the rotation sensor 6. The sensor failure diagnosis device according to claim 5, wherein the failure is regarded as a failure. 8. A blow-up prevention means for forcibly reducing the fuel injection amount to zero when the failure diagnosis means determines that the rotation sensor has failed.
Or a sensor failure diagnosis device in the fuel injection device according to 7.