JPH09195842A - Apparatus for diagnosing trouble of throttle opening degree detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diagnose a trouble surely and reliably without being affected by an error of a throttle opening detecting signal and a resolving function of the detecting side. SOLUTION: When a vehicle speed VSP after starting from a stopping condition does not exceed a set vehicle speed VSPS and diagnosis based on the vehicle speed is allowed, the output value of a throttle opening sensor is compared with a set value THVS1 and in the case THV<THVS1, it is judged that a throttle opening detecting system gets out of order. Then, if the following situation occurs successively set times or more that the output value of the throttle opening sensor does not once reach the set value during a period from the start of an engine to the time when the vehicle speed reaches a set vehicle speed after repeated starting and stopping, it is determined that the throttle opening detecting system gets out of order as the final diagnosis. Consequently, even in the case a precise trouble judgment is hard to be made due to an effect of an error of a throttle opening detection signal and the resolving function in the detection side upon the judgment level, a precise trouble judgment can be carried out and reliability of the diagnosis can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosis device for a throttle opening detection system for diagnosing a failure of a throttle opening detection system related to a throttle opening sensor for detecting the opening of a throttle valve.

[0002]

2. Description of the Related Art Conventionally, a failure of an idle switch for detecting an idle operation state of an engine or a throttle opening sensor for detecting a throttle opening has been detected by a self-diagnosis function provided in a control system. When an abnormality occurs, a warning is issued to the driver to call attention, and a malfunction of the system due to the input of abnormality data is avoided.

For example, Japanese Unexamined Patent Publication (Kokai) No. 62-96758 discloses a technique for diagnosing an abnormality of an idle switch. In this prior art, the condition for turning on the idle switch is satisfied from the basic injection time and the engine speed. Despite this, when the idle switch is not turned on for a predetermined period of time, it is determined that an abnormality has occurred in the idle switch, and an alarm is issued to notify the driver.

[0004]

By the way, the throttle opening sensor for detecting the throttle opening generally has such a characteristic that its output voltage increases substantially linearly as the throttle opening increases. In the case of performing a failure diagnosis for the throttle opening sensor, a technique is often adopted to determine a failure when the output voltage level is equal to or lower than a voltage level corresponding to full throttle closing or higher than a voltage level corresponding to full throttle opening. .

However, if the failure determination level is uniquely set for the throttle opening detection signal as described above to perform the failure diagnosis, the signal level corresponding to the throttle fully closed becomes a minute level. It may be difficult to determine the determination level depending on the error range of the detection signal, the resolution of the detection side, and the like. In such a case, not only a correct failure diagnosis may not be possible, but also a false diagnosis may occur.

The present invention has been made in view of the above circumstances, and enables reliable and reliable failure diagnosis without being affected by errors in the throttle opening detection signal and resolution on the detection side. An object of the present invention is to provide a failure diagnosis device for a throttle opening detection system.

[0007]

According to the first aspect of the present invention,
As shown in the basic configuration diagram of FIG. 1A, the throttle opening monitor that monitors the output value from the throttle opening sensor that detects the opening of the throttle valve from the stopped state until the vehicle speed reaches the set vehicle speed. Means, and the output value from the throttle opening sensor monitored by the throttle opening monitoring means is compared with a set value, and the output value is set to the set value even after the vehicle speed reaches the set vehicle speed from the stopped state. When the above does not occur, the throttle opening detection system related to the throttle opening sensor is provided with a throttle opening detection system failure determination means for determining that an abnormality has occurred.

According to a second aspect of the present invention, in the first aspect of the present invention, the throttle opening detection system failure determination means is configured to detect the throttle opening degree detection system when the diagnosis result which is determined to be abnormal occurs for a set number of times. Is characterized in that it is determined to be faulty.

According to the third aspect of the invention, as shown in the basic configuration diagram of FIG. 1 (b), whether or not the current operating region specified by the engine speed and the vehicle speed is the diagnostic execution region for executing the failure diagnosis. When the current operation area is determined to be the diagnosis execution area by the area determination means that determines whether or not the above-mentioned area determination means determines the output value from the throttle opening sensor that detects the opening of the throttle valve, it is compared with the set value. When the output value is equal to or less than the set value, the throttle opening detection system failure determination means for determining that the throttle opening detection system related to the throttle opening sensor is in failure is provided.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the region determining means divides the present operating region specified by the engine speed and the vehicle speed by the throttle opening at the normal time. It is characterized in that it is determined to be a diagnosis execution region when it corresponds to a region equal to or larger than the set throttle opening degree of the region map according to the engine speed and the vehicle speed.

That is, according to the first aspect of the invention, the output value from the throttle opening sensor is monitored from the stopped state until the vehicle speed reaches the set vehicle speed, and when the output value never exceeds the set value. It is determined that an abnormality has occurred in the throttle opening detection system related to the throttle opening sensor. At that time, in the invention according to the second aspect, when the diagnosis result which is determined to be abnormal is continuously set times, it is determined that the throttle opening detection system is out of order.

According to the third aspect of the present invention, the diagnosis is executed when it is determined that the current operation area specified by the engine speed and the vehicle speed is the diagnosis execution area for executing the failure diagnosis. When the output value from the opening sensor is less than or equal to the set value, it is determined that the throttle opening detection system related to the throttle opening sensor is out of order. that time,
In the invention according to claim 4, the current operating region specified by the engine speed and the vehicle speed is equal to or more than the set throttle opening degree in the area map based on the engine speed and the vehicle speed divided by the normal throttle opening degree. When it corresponds to the area, it is determined to be the diagnosis execution area.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 4 show the first embodiment of the present invention.
2 is a flowchart showing a failure diagnosis routine of a throttle opening detection system, FIG. 3 is a schematic configuration diagram of an engine control system, and FIG. 4 is a circuit configuration diagram of an electronic control system.

In FIG. 3, reference numeral 1 is an engine,
The figure shows a horizontally opposed four-cylinder engine. An intake manifold 3 communicates with each intake port 2a formed in a cylinder head 2 of the engine 1, a throttle chamber 5 communicates with the intake manifold 3 via an air chamber 4, and an intake pipe is provided upstream of the throttle chamber 5. An air cleaner 7 is attached through the air cleaner 6.

Further, the air cleaner 7 of the intake pipe 6
An intake air amount sensor 8 of, for example, a hot wire type is provided immediately downstream of the throttle valve, and a throttle opening sensor for detecting a throttle opening is provided on a throttle shaft of a throttle valve 5a provided in the throttle chamber 5. 9
a and a throttle sensor 9 having a built-in idle switch 9b that is turned on when the throttle valve is fully closed. In the present embodiment, the opening sensor 9a has a characteristic that its output voltage increases substantially linearly as the throttle opening increases.

Further, an idle speed control valve (ISCV) 11 for adjusting the amount of idle air is provided in a bypass passage 10 connecting the upstream side and the downstream side of the throttle valve 5a, and the intake manifold is further provided. An injector 14 is exposed immediately upstream of each intake port 2a of each cylinder No. 3 and an ignition plug 15a whose tip is exposed to the combustion chamber is attached to each cylinder head 2 of each cylinder. An igniter 16 is connected to the ignition coil 15b connected to the ignition plug 15a.

The injector 14 has a fuel supply path 17
The fuel tank 18 is communicated with the fuel tank 18 via the fuel tank 18, and an in-tank type fuel pump 19 is provided in the fuel tank 18. The fuel from the fuel pump 19 is pressure-fed to the injector 14 and the pressure regulator 21 through the fuel filter 20 provided in the fuel supply path 17, and is returned from the pressure regulator 21 to the fuel tank 18 to be injected by the injector. The fuel pressure for 14 is adjusted to a predetermined pressure.

A knock sensor 22 is attached to the cylinder block 1a of the engine 1, and a cooling water temperature sensor 24 is exposed to a cooling water passage 23 that connects the left and right banks of the cylinder block 1a. Further, a front O2 is provided at a gathering portion of the exhaust manifold 25 communicating with the exhaust port 2b of the cylinder head 2.
A sensor (FO2 sensor) 26a is exposed, and a front catalytic converter 27a is provided on the downstream side of the FO2 sensor 26a. A rear catalytic converter 27b is provided immediately downstream of the front catalytic converter 27a, and a rear O2 sensor (RO2 sensor) 26b is exposed downstream of the rear catalytic converter 27b.

The RO2 sensor 26b is, for example,
The FO2 sensor 2 is provided for diagnosing catalyst deterioration and the like.
Deterioration of the catalyst is diagnosed based on the result of comparison between the output of 6a and the output of the RO2 sensor 26b.

A crank rotor 28 is mounted on a crank shaft 1b supported by the cylinder block 1a, and a protrusion (or a slit) corresponding to a predetermined crank angle is detected on the outer circumference of the crank rotor 28. A crank angle sensor 29 including a magnetic sensor (electromagnetic pickup or the like) or an optical sensor or the like is installed oppositely. Further, the camshaft 1c of the cylinder head 2
The cam rotor 30 is continuously connected to the cam rotor 30.
Similarly, a cam angle sensor 31 for discriminating a cylinder, which is composed of a magnetic sensor or an optical sensor, is provided oppositely.

On the other hand, in FIG. 4, reference numeral 40 is an electronic control unit (ECU) for controlling the engine 1. The ECU 40 includes a CPU 41, a ROM 42 and a RAM 4.
3, a backup RAM 44, and an I / O interface 45 are mainly composed of a microcomputer connected to each other via a bus line 46, and a constant voltage circuit 47 for supplying a stabilizing voltage to each part, the I / O described above. A drive circuit 48 that drives actuators by a signal from an output port of the interface 45, an A / D that converts analog signals from sensors to digital signals
Peripheral circuits such as the converter 49 are incorporated.

The constant voltage circuit 47 is directly connected to the ECU.
It is connected to a battery 51 via a relay contact of the relay 50, and the relay coil of the ECU relay 50 is connected to the battery 51 via an ignition switch 52.

Further, the I / O interface 45 is also provided.
The idle switch 9b, the knock sensor 22, the crank angle sensor 29, the cam angle sensor 31, and the vehicle speed sensor 32 are connected to the input port of the intake air amount sensor 8, the throttle opening sensor 9a, the cooling water temperature sensor. 24, the FO2 sensor 26a, and the RO2 sensor 26b are connected via the A / D converter 49, and the battery voltage VB is input to the A / D converter 49 for monitoring.

On the other hand, the above I / O interface 45
An igniter 16 is connected to an output port of the MIL lamp 53, which is arranged on the ISCV 11, the injector 14, and an instrument panel (not shown) via the drive circuit 48 to centrally display various alarms. Are connected.

The ROM 42 stores an engine control program, various failure diagnosis programs, fixed data such as maps, and the RAM 43 stores the fixed data.
The data after processing the output signals of each of the sensors and the switches and the data processed by the CPU 41 are stored. The backup RAM 44 stores various learning maps, trouble data, etc., and regardless of whether the ignition switch 52 is ON or OFF, backup power is constantly supplied from the constant voltage circuit 47, and the ignition switch 52 is OFF. The data is sometimes retained.

The trouble data can be read out to the outside by connecting the serial monitor 60 to the ECU 40 via the connector 54. The serial monitor 60 is disclosed in Japanese Patent Laid-Open No. 2-73131 previously filed by the applicant.
The details are described in Japanese Patent Publication No.

The CPU 41 processes the detection signals from the sensors and switches input via the I / O interface 45, the battery voltage, etc. according to the control program stored in the ROM 42, and the RAM 4
3 and various data stored in the backup RAM 44, fixed data stored in the ROM 42, and the like, various control variables such as the fuel injection amount, the ignition timing, and the duty ratio of the drive signal with respect to the ISCV 11 are calculated, and various actuators are calculated. Driven to perform various controls such as air-fuel ratio learning control, ignition timing control, idle speed control, and the like.

At this time, in the microcomputer centering on the CPU 41, the failure diagnosis of each detection system for detecting the engine operating state is performed, and when it is determined that the system is normal, each measured data is adopted as the control data. Therefore, failure diagnosis of the throttle opening detection system according to the present invention, that is, abnormality of output value due to deterioration or failure of the throttle opening sensor 9a, rattling of the sensor mounting portion, disconnection of signal line, etc. The functions of the throttle opening monitoring means and the throttle opening detection system failure determination means for diagnosing an abnormality are realized.

The failure diagnosis processing of the throttle opening detection system will be described below with reference to the flowchart of FIG.

The flowchart of FIG. 2 shows a failure diagnosis routine of the throttle opening detection system which is activated at every set time after the system power is turned on to the ECU 40 and the system is initialized. In this routine, first, in step S101, the vehicle speed is set. It is checked whether the vehicle speed VSP based on the signal from the sensor 32 is 0 and the vehicle is stopped. When executing this routine, it is assumed that the signal from the vehicle speed sensor 32 has been confirmed to be normal from the execution state of other diagnostic programs or various processes.

When the vehicle is in the stopped state with VSP = 0 in step S101, the process proceeds to step S102 to clear the diagnostic condition determination flag FVSP (FVSP ← 0), and then in step S103 clear the abnormality count flag FTH. (F
TH ← 0), and it is checked in step S114 whether or not the NG determination count value C (initial value is 0), which will be described later, is greater than or equal to a set value CS (for example, 15 times).

As will be described later, the diagnostic condition determination flag FVSP monitors the signal from the throttle opening sensor 9a from the stopped state until the set vehicle speed is reached, and the driver's accelerator pedal depressing operation is performed to some extent. This is a flag to execute the diagnosis in the operation area that is surely performed, and
When P = 0, the diagnostic execution is permitted because the diagnostic condition is satisfied in the running state from the stopped state to the set vehicle speed or less, and when the vehicle speed exceeds the set vehicle speed, FVSP = 1 is set,
Diagnosis is prohibited until the next stop and start again.

Further, the abnormal count flag FTH
When FTH = 0, the number of times that the result of the diagnosis based on the vehicle speed in the above-mentioned operating region is the result of the diagnosis that the output value of the throttle opening sensor 9a is not more than the set value and is regarded as abnormal, That is, it is a flag for counting the number of times of diagnosis for which an abnormality determination is made, and when the output value of the throttle opening sensor 9a exceeds a set value or when the NG determination count value C is counted up. , FTH = 1 is set, and counting up is prohibited until the next vehicle speed diagnosis result is obtained.

In other words, if only the diagnosis under the above-mentioned conditions when the vehicle speed is equal to or lower than the set vehicle speed, an erroneous diagnosis occurs in the case of inertial traveling on a downhill or the like or a situation where wheel slip occurs on a low friction road surface. Therefore, if the diagnosis result by the vehicle speed under the above conditions is abnormal, the above N
The number of abnormalities is counted by the count value C for G judgment, and the throttle opening degree detection system including the throttle opening degree sensor 9a and the periphery of the sensor mounting portion, the signal line and the like is provided only when the value exceeds the set value CS. It is determined that a failure has occurred.

Therefore, when the vehicle is stopped, steps S101 → S102 →
When the process proceeds from S103 to S114, C <CS, and at this time, the throttle opening detection system is determined to be normal for the time being, and the routine is exited. When C ≧ CS, it is determined that a failure has occurred in the throttle opening detection system, the process proceeds to step S115, and the throttle opening detection system NG flag FNGTH indicating that the throttle opening detection system has a failure is stored in the backup RAM 44. At the same time, the MIL lamp 53 is turned on to warn the driver.

Next, when the driver depresses the accelerator pedal from the stopped state to start the vehicle and VSP ≠ 0 in step S101, the process proceeds from step S101 to step S104 to set the vehicle speed VSPS to the set vehicle speed VSPS.
Check if it exceeds (eg 40km / h),
When VSP≤VSPS, the routine proceeds from step S104 to step S105, refers to the value of the diagnostic condition determination flag FVSP, and checks whether or not the execution of the diagnosis based on the vehicle speed is permitted.

As a result, in the above step S105, FVS
When P = 1 and vehicle speed diagnosis is prohibited,
That is, after starting from the stopped state, the vehicle speed VSP once exceeds the set vehicle speed VSPS, and then decelerates to the set vehicle speed VS.
When it becomes equal to or lower than PS, the routine jumps to the above-mentioned step S114 for comparing the NG determination count value C with the set value CS, FVSP = 0, and the vehicle speed VS is started from the stopped state.
When P does not exceed the set vehicle speed VSPS and the diagnosis based on the vehicle speed is permitted, the routine proceeds to step S106 and thereafter to start the diagnosis.

In the diagnostic process after step S106, the output value THV of the throttle opening sensor 9a is compared with the set value THVS1 (for example, a value corresponding to 10 deg) in step S106,
Check whether or not the throttle opening suitable for the driving condition is obtained. This set value THVS1 is equivalent to the minimum throttle opening in a normal state, which is obtained when the vehicle starts from a stopped state and becomes a running state below the set vehicle speed.
When V <THVS1, it means that the throttle valve 5a has not opened by the original opening degree even though the vehicle is starting from the stopped state and is in the running state, so that an abnormality has occurred in the throttle opening degree detection system. Judgment is made, and the abnormal count flag FTH is cleared in order to start counting the NG judgment count value C. The process returns to step S103. At this stage, C <CS still exists, so the routine exits from step S114.

On the other hand, in the above step S106, THV ≧
When THVS1, it is determined that the throttle opening detection system is normal, the process proceeds to step S107, where the NG determination count value C is cleared (C ← 0), and the abnormality count flag FTH is set (FTH ← 1), the throttle opening detection system NG flag FNGTH is cleared in step S109 (FNGTH ← 0), and the flow proceeds to step S114. even here,
Since C <CS, the routine exits from step S114.

Thereafter, the routine is repeated and the vehicle speed VS
When P increases and exceeds the set vehicle speed VSPS (VSP> V
SPS), the process proceeds from step S104 to step S110, and the diagnosis condition determination flag FVSP is set to prohibit the diagnosis based on the vehicle speed.
Is set (FVSP ← 1), and the value of the abnormal count flag FTH is referred to in step S111.

In step S111, FTH = 1, and the output value THV of the throttle opening sensor 9a is set to the set value THV during the period from the stop state until the vehicle speed reaches the set vehicle speed.
When the count value C for NG determination has been cleared since S1 or more, the routine jumps to step S114 and similarly exits the routine because C <CS, FTH = 0, and the vehicle speed changes from the stopped state. If the output value of the throttle opening sensor 9a has never exceeded the set value before reaching the set vehicle speed, the routine proceeds to step 112, where the NG determination count value C is incremented (C ← C + 1), and the step At S113, the count value C for NG judgment is thereafter used until the vehicle stops (until the vehicle restarts and the next diagnostic result is obtained).
In order not to count up, the abnormal count flag FTH is set (FTH ← 1), and the routine proceeds to step S114.

The above processing is repeated, and when C ≧ CS in step S114, that is, after the engine has been started and stopped, the vehicle is once started and stopped again until the vehicle speed reaches the set vehicle speed. Throttle opening sensor 9a
When the output value of is not more than the set value continuously for the set number of times or more, the output value is abnormal due to deterioration or failure of the throttle opening sensor 9a itself, the backlash of the sensor mounting portion occurs,
Alternatively, a final diagnosis that a failure has occurred in the throttle opening detection system due to disconnection of the signal line, etc.
From S114 to step S115, the throttle opening detection system N
The G flag FNGTH is stored in the backup RAM 44, and the MIL lamp 53 is turned on to warn the driver.

That is, the abnormality is judged by whether or not the output value of the throttle opening sensor 9a is equal to or more than the set value during the period from the stop state in which the driver surely operates the accelerator pedal to some extent to the set vehicle speed. Thus, when the output value of the throttle opening sensor 9a is equal to or lower than the level corresponding to full throttle closing or equal to or higher than the level corresponding to full throttle opening, a unique determination level for the throttle opening detection signal is used to determine failure. In the conventional diagnosis, even if the judgment level is affected by the error of the throttle opening detection signal, the resolution of the detection side, etc. and it is difficult to make an accurate failure judgment, it is possible to make an accurate failure judgment. Can be improved.

In this case, it is possible to widen the output range from the fully closed throttle to the fully open throttle to increase the resolution of the throttle opening, and increase the resolution to expand the range of the output value of the throttle opening sensor 9a. Can also be accurately diagnosed. In addition, in order to make a final diagnosis that the throttle opening detection system is out of order when the number of times the result of diagnosis by vehicle speed is abnormal exceeds the set number, the There will be no erroneous diagnosis in the situation where the slip occurs.

5 and 6 relate to the second embodiment of the present invention, FIG. 5 is a flow chart showing a failure diagnosis routine of the throttle opening detection system, and FIG. 6 is an explanatory diagram showing the characteristics of the area map.

In this embodiment, in the first embodiment described above, the throttle opening detection system is determined to be abnormal when the slot opening exceeding the set value cannot be obtained from the stopped state until the set vehicle speed is reached. On the other hand, when the output value of the throttle opening sensor 9a is equal to or less than the set value in the operating region where the throttle opening cannot be larger than the set throttle opening, it is determined that the throttle opening detection system has a failure.

The failure diagnosis routine of the throttle opening detection system in this embodiment is shown in FIG. 5 and is executed at every set time. In this routine, in step S201, the vehicle speed sensor 3
Vehicle speed VSP, crank angle sensor 2 based on signals from 2
When the engine speed NE based on the signal from 9 is read,
In step S202, the current operating region is specified by referring to the region map based on the vehicle speed VSP and the engine speed NE,
Data FAREA stored in the corresponding area of the map
Read.

When executing this routine, the signal from the vehicle speed sensor 32 and the signal from the crank angle sensor 29, which is the basic timing of the engine control system and serves as the basis for calculating the engine speed, are the other diagnostic programs. Alternatively, it is assumed that the execution state of various processes has been confirmed to be normal.

As shown in FIG. 6, the region map is determined according to the characteristics of the transmission (not shown), and the engine speed NE and the vehicle speed VSP are divided by the throttle opening.
Data FAREA for determining whether or not to execute the diagnosis is stored in each area indicated by and, and FAREA = 1 for instructing the execution of the diagnosis in an area equal to or larger than the set throttle opening (for example, 40 deg). Value is stored, and in other areas, a value of FAREA = 0 that prohibits diagnosis is stored.

Therefore, the above steps S202 to S2
Go to 03 and check whether the value of data FAREA is 1 or not.
When = 0, it is not in the area to be diagnosed, so the routine exits. When FAREA = 1, it is judged that the diagnosis is executed, and the routine proceeds from step S203 to step S204.

Then, in step S204, the output value THV of the throttle opening sensor 9a is set to the set value THVS2 (for example, 2
It is checked whether it is less than or equal to 0 deg), and THV> THVS2
At this time, the throttle opening detection system is judged to be normal, and the routine proceeds to step S205, where the throttle opening detection system NG flag FNGTH of the backup RAM 44 is cleared (F
NGTH ← 0) The routine is exited. On the other hand, when THV ≦ THVS2, the output value of the throttle opening sensor 9a indicates an impossible throttle opening. Therefore, it is determined that a failure has occurred in the throttle opening detection system. In step S206, the throttle opening detection system NG flag FNGTH is set (F
NGTH ← 1) Store in the backup RAM 44 and exit the routine.

In the present embodiment, similar to the first embodiment described above, even when it is difficult to make an accurate failure determination due to the error of the throttle opening detection signal, the resolution of the detection side, etc., the failure determination can be made accurately. The failure can be detected in a shorter time than the first embodiment.

[0053]

As described above, according to the first aspect of the present invention, the output value from the throttle opening sensor is monitored from the stopped state until the vehicle speed reaches the set vehicle speed, and the output value is monitored. When the value does not exceed the set value even once, it is determined that an abnormality has occurred in the throttle opening detection system related to the throttle opening sensor. Further, according to the invention of claim 3, it is specified by the engine speed and the vehicle speed. When it is determined that the operation area of is the diagnosis execution area for executing the failure diagnosis, the diagnosis is executed, and as a result, when the output value from the throttle opening sensor is less than or equal to the set value, the throttle opening detection related to the throttle opening sensor is detected. In order to determine that the system has a failure, failure occurs when the output value of the throttle opening sensor is below the level equivalent to full throttle closing or above the level equivalent to full throttle opening. Even in the case where it is difficult to make an accurate failure determination in the conventional diagnosis based on a unique determination level for the throttle opening detection signal that makes a determination, the determination level is affected by the error of the throttle opening detection signal, the resolution of the detection side, etc. The failure diagnosis can be performed reliably and reliably without being affected by the error of the throttle opening detection signal and the resolution of the detection side.

In this case, according to the second aspect of the invention, when the result of the diagnosis according to the first aspect of the invention is that the diagnosis result has been determined to be abnormal for a set number of times, it is determined that the throttle opening detection system has failed. Therefore, it is possible to prevent erroneous diagnosis in the case of inertial running on a downhill or the like, or a situation where a wheel slip occurs on a low friction road surface, and a more reliable diagnosis can be performed.

In the invention according to claim 4, the invention according to claim 3
In the diagnosis according to the invention described above, the current operating region specified by the engine speed and the vehicle speed is a region equal to or more than the set throttle opening of the region map based on the engine speed and the vehicle speed divided by the throttle opening during normal operation. When the above condition is met, it is determined to be in the diagnosis execution area, so that the failure can be diagnosed quickly and accurately.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a flow chart showing a failure diagnosis routine of a throttle opening detection system according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an engine control system of the above.

FIG. 4 is a circuit diagram of the electronic control system of the above.

FIG. 5 is a flowchart showing a failure diagnosis routine of a throttle opening detection system according to the second embodiment of the invention.

FIG. 6 is an explanatory diagram showing the characteristics of the area map.

[Explanation of symbols]

5a ... Throttle valve 9a ... Throttle opening sensor VSP ... Vehicle speed NE ... Engine speed THV ... Throttle opening sensor output value THVS1, THVS2 ... Set value C ... NG determination count value (number of diagnostic results determined to be abnormal) ) CS… set value (set times)

Claims (4)

[Claims] 1. A throttle opening monitoring means for monitoring an output value from a throttle opening sensor for detecting an opening of a throttle valve from a stopped state until a vehicle speed reaches a set vehicle speed, and the throttle opening monitoring means. Compare the output value from the throttle opening sensor monitored by the set value with the set value, and if the output value never exceeds the set value during the period from the stop state until the vehicle speed reaches the set vehicle speed, the throttle opening A failure diagnosis device for a throttle opening detection system, comprising: a throttle opening detection system failure determination unit that determines that an abnormality has occurred in a throttle opening detection system related to a sensor. 2. The throttle opening degree detection system failure determination means determines that the throttle opening degree detection system is out of order when a diagnosis result which is determined to be abnormal has continued for a set number of times. A failure diagnosis device for a throttle opening detection system according to Item 1. 3. A region determining means for determining whether or not the current operating region specified by the engine speed and the vehicle speed is a diagnostic execution region for executing a failure diagnosis, and the current operating region is diagnosed by the region determining means. When it is determined to be in the execution range, the output value from the throttle opening sensor that detects the opening of the throttle valve is compared with the set value, and when the output value is less than or equal to the set value, the throttle related to the throttle opening sensor is A throttle opening detection system failure diagnosis device comprising: a throttle opening detection system failure determination means for determining that the opening detection system is in failure. 4. The region determining means sets a throttle opening of a region map based on the engine speed and the vehicle speed in which the current operating region specified by the engine speed and the vehicle speed is divided by the throttle opening during normal operation. 4. The fault diagnosis device for a throttle opening detection system according to claim 3, wherein the fault diagnosis device is determined to be in a diagnosis execution region when it corresponds to a region equal to or higher than a degree.