JPS6011675A - Diagnosing method of trouble of fuel control device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To easily diagnose a trouble in a switch, by diagnosing the trouble of short circuit or breaking caused in the switch, which provides two operating points restricting the actuating range of a throttle valve driving step motor, on the basis of a result comparing a number of steps, when the operatng point is switched, with several kinds of preset values. CONSTITUTION:The opening of a throttle valve 43 interposed in an intake pipe 44 is controlled by a step motor 51 driven relating to the control amount of an accelerator pedal 16, and the throttle valve 43 is normally set to an idle position by urging with a spring 53 an actuating lever 52 fixed to a valve shaft 42. A switch having operating points S1, S2 for detecting the idle position and full opening position of the throttle valve 43 is provided in a moving route of said actuating lever 52. Then a trouble in the switch is diagnosed on the basis of an acting condition of the switch between the first, fourth preset values and the second, third preset values by providing the first and the third values preset smaller and similarly the second and the fourth values preset larger by a predetermined number than the number of steps when the operating points S1 and S2 are switched.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a fuel control device for an internal combustion engine that is required for an automatic transmission operating device in an automobile, and more specifically, a fuel control device for controlling a throttle valve of a carburetor or a control lever for a fuel injection pump. The present invention relates to a method for diagnosing a failure of a fuel injection control Il device in an internal combustion engine.

For example, in a vehicle equipped with an automatic transmission that automatically operates a gear transmission in conjunction with a clutch mechanism, the transmission is automatically operated while the accelerator pedal is depressed, and the engine is activated when shifting. To prevent racing, it is necessary to return the carburetor throttle valve or fuel injection pump control lever to the idle position when changing gears, regardless of the amount of operation or depression of the accelerator pedal. For this purpose, the accelerator pedal is mechanically disconnected from the carburetor throttle valve or fuel injection pump control lever in the engine (hereinafter referred to simply as the throttle valve). At the same time, an accelerator sensor is attached to the accelerator pedal to detect the amount of operation, and the step motor is controlled by an electronically controlled aTl device according to the detection signal of the accelerator sensor and state changes such as starting and shifting. It is proposed that That is, the first position detects the idle position and the fully open position of the throttle valve. A switch having a second operating point is provided, and a first resistance value of the accelerator sensor at the first operating point and a second resistance value of the accelerator sensor at the second operating point are respectively controlled by a microcomputer as an electronic control device. and between the first resistance value and the second resistance value (
The step motor is driven based on the change in resistance caused by the operation of the accelerator pedal, and the opening degree of the throttle valve is controlled.

However, if the switch that regulates the operating range of the step motor by the electronic control device is short-circuited or opened (cut off), the step motor may operate beyond its control range due to the signal value from the microcomputer. This may cause the engine to run out of control.

In view of these problems, the object of the present invention is to provide a fault diagnosis method for a fuel control & II device in an internal combustion engine that can easily detect an open or short circuit in a switch that regulates the idle position and fully open position of a throttle valve. It's about doing.

For this reason, the present invention provides a first switch which switches depending on the signal from the accelerator sensor that detects the operating position of the accelerator pedal and the idle position and maximum fuel position of the throttle valve of the carburetor or the controller 1 to roll lever of the fuel injection pump, respectively. A step motor connected to the throttle valve or the controller 1 to the roll lever is driven by the output signal of the electronic control device which receives the signal of the switch having the second operating point as input, and the step motor connected to the throttle valve or the controller 1 to the roll lever is driven. The control device includes a counter that counts the number of operating steps of the step motor, sets the count to O in a non-excited state, stores a preset value set as an idle position, and controls the throttle valve or control lever to increase or increase fuel. Every time one step is sent in the decreasing direction, the number of steps is counted by ±1, and the stored value of the previous idle position is updated to the number of steps when the operating point of the first switch is switched, and this stored value and the count are updated. In an internal combustion fuel control device in which the throttle valve or control lever is driven in proportion to the difference between the throttle valve and the control lever, the first operating point of the switch is set to a first set value that is smaller by a predetermined number, and a second set value that is larger by a predetermined number, and a third set value that is smaller by a predetermined number than the number of steps at which the second operating point of the switch changes; a fourth set value that is larger by a predetermined number, and the operating state of the switch outside the interval between the first set value and the fourth set value, and the second set value and the A fault diagnosis of open or short circuit of the switch is performed based on the operating state of the switch inside the interval with the third set value.

The present invention will be described based on an embodiment. First, as shown in FIG. 1, the automatic gear shift operating device includes a clutch mechanism 2, a clutch actuator 5 that connects and disconnects the clutch mechanism 2, a synchronized mesh transmission 21, and a synchronous mesh transmission 21. It includes a transmission actuator 7 that selects this shift position, and an electronic control device 10 that controls each actuator 5, 7.

The clutch mechanism 2 connects a friction plate supported by an input shaft 22 of a gear transmission 21 to a flywheel 1a fixed to the crankshaft 1 of the engine via a known pressure plate 2a to apply a spring force to the flywheel 1a. The rotational connection is obtained by pressing with force, and this pressing is released when the release lever 3 is pulled to the right by the clutch actuator 5.

As shown in FIG. 2, the clutch actuator 5 includes a cylinder 26 fitted with a piston 38 to define a liquid chamber 40.25, and a rod 4 connected to the piston 38 connected to the release lever 3.

The rod 27 is connected to the piston 38, and a stroke sensor 36 is provided to detect this displacement.

The liquid chamber 40 is connected to the discharge port of the hydraulic pump 31 constituting the hydraulic unit 6 via normally closed electromagnetic on-off valves 33 and 32, and the liquid chamber 40 is also connected to the normally closed electromagnetic on-off valve 35 and the normally open electromagnetic on-off valve 33, 32. They are connected to a liquid tank 39 via type electromagnetic on-off valves 34, respectively. Further, the liquid chamber 25 is directly connected to a liquid tank 39.

The normally closed electromagnetic on/off valves 32 and 33 are opened only during the gear shift operation, and when the normally open electromagnetic on/off valve 34 is closed, the hydraulic pump 31
Pressure fluid is supplied to the fluid chamber 40, and the piston 38 moves to the right, disengaging the clutch. On the other hand, when the normally open electromagnetic on-off valve 34 is closed and the normally closed electromagnetic on-off valve 35 is opened and closed intermittently, the liquid pressure in the liquid chamber 40 is gradually released, and the piston 38 is moved to the left by the force of a spring (not shown). direction and connect the clutch. The operating speed of the clutch actuator 5 is controlled by the duty ratio of pulses applied to the normally open electromagnetic on-off valve 35.

As shown in Fig. 1, the transmission actuator 7 is actually composed of a hydraulic actuator that performs a select operation and a hydraulic actuator that performs a shift operation like a normal manual synchronized mesh transmission. , the gear shift position (gear meshing position) is detected by the gear shift position sensor 8. When driving on a normal flat road, acceleration and deceleration are automatically performed from start to high gear. In preparation for hill driving or reversing that requires braking, the selector lever 13 selects N (neutral position), D (automatic shift), ■ (first gear), ■ (second gear), ■ (1st, 2nd, etc.). The driving mode can be switched to each of the following ranges: 3-speed automatic shifting) and R (reverse) range, and the switching position of this range is detected by the driving mode sensor 14.

The electronic control unit 1o includes a microprocessor 12 and a memory 1.
1 and an interface 9. Changes in the state of each operating part, which will be described later, are input to the interface 9 as digital signals, while these input signals and R of the memory 11 are input to the interface 9.
A digital signal calculated by the microprocessor 12 is applied to the clutch actuator 5 and the transmission actuator 7 based on a control map stored in advance in the OM.

In order to detect the engine speed, an electromagnetic pickup type rotation sensor 24 is arranged on the outer circumferential side of the flywheel 1a, and this digital signal is input to the interface 9. Similarly, the input shaft 22 of the synchronous mesh transmission 21 is provided with a rotation sensor 23, and the output shaft 20 is provided with a vehicle speed sensor 19, and these signals are input to the interface 9.

Further, an accelerator sensor 15 and a brake sensor 17 are disposed on the brake pedal 18 and the accelerator sensor 15 to detect the amount of operation of the accelerator pedal 16, respectively. An operation mode sensor 14 is arranged adjacent to the selector lever 13.

Such a configuration is well known in Japanese Patent Laid-Open No. 51-121657, etc., and is not directly related to the gist of the present invention, so a description thereof will be omitted.

As shown in FIG. 1, a throttle valve 43 is disposed with a valve shaft 42 in order to control the amount of intake air taken into the cylinders of an engine 45 from an air purifier 41 through an intake pipe 44, and this opening degree is adjusted by the accelerator. It is controlled by a step motor 51 that is driven in relation to the amount of operation of the pedal 16. That is, an operating lever 52 is fixedly supported on the valve shaft 42, and a spring 53 normally biases the throttle valve 43 to the idle position.

A drive lever 54 is freely rotatably supported on the valve shaft 42.
The adjustment pole l~46 screwed and supported by this is the operating lever 52.
It is designed to be abutted against the back of the Drive lever 54
is connected to one end of a link 48 with a pin 47, and the other end is connected with a pin 49 to an arm 50 of a step motor 51. In order to detect the idle position and the fully open position of the throttle valve 43, an operating point S+ is provided in the movement path of the actuating lever 52.

A switch with S2 is provided. Switch operating point S
+ closes the circuit when the throttle valve 43 is at the idle position, and opens when the opening degree of the throttle valve 43 increases from the idle position. Further, the operating point S2 of the switch is normally open and closes when the throttle valve 43 reaches the fully open position. The operating points S+ and S2 of the switch can be set, for example, by a cam formed on the operating lever 52.

The step motor 51 is driven by a digital signal from the electronic control device 10. In the non-excited state, the step motor 51 may be rotated by an external force in a counterclockwise direction compared to the state shown in FIG. 1, and the drive lever 54 may be rotated in the same direction about the valve shaft 42. In order to synchronize the operating lever 52 and the drive lever 54, when the accelerator pedal 16 is operated, the electronic control device 1 is activated as shown in FIG.
A preset value (count) ■ set to 0 is applied to the step motor 51, and the drive lever 54 is rotated until poles 1 to 46 hit the operating lever 52 in the idle position, and the operating point S+ of the switch changes from closed to The position at which the valve is opened is stored in the electronic control unit 10 as an idle position x0.

Furthermore, if the resistance value of the accelerator pedal 15 varies, the drive lever 54 may not be rotated until the throttle valve 43 is fully opened even if the accelerator pedal 16 is depressed to the maximum extent. When the number of steps of the step motor 51 reaches the set value Z, the step motor 51 is continuously driven, and when the operating lever 52 reaches the operating point S2 of the switch (step number XF), the step motor 51 is driven continuously. The motor 51 is configured to be stopped.

The present invention constantly diagnoses the failure of a switch having an operating point S++82 that regulates the operating range of the step motor 51.
As a digital signal value applied to the step motor 51, as shown in FIG.

Set a set value Xl smaller than the number of steps x 0 when the operating point S+ of the switch closes, and a set value x 2 larger than the number of steps x 0, and set the operating point S of the switch.
Number of steps when 2 closes x Set value smaller than F x
3 and a setting value x 4 larger than the number of steps x F, and these setting values x! The failure of the switch is diagnosed from the open/closed state of the operating point S++82 of the switch at ~×4. That is, the step motor 51
If the switch is closed when the number of steps is inside the interval of set value x 2 to x 3, the switch is closed.
If the switch is open when the number of steps of the step motor 51 is outside the setting 11i None of them set off alarms.

A determination program that determines whether the switch signal is normal or not is executed in a task that is activated every 100 IIISeC. FIG. 4 shows a flowchart of the control program described above. In the figure, p11 to p20 indicate each step of the flowchart. When the task of the determination program is activated, the calculation part is set to pll (13-). In p12, it is determined whether the operating point $1 of the switch is a leap or not. If the operating point S1 of the switch is open, in p13 the signal value from the microcomputer, that is, the number of steps of the step motor x is determined from the set value x 2. is also large. If the number of steps x is smaller than the set value x2, it is determined to be normal at p20, and the process ends at step 916.

Further, if the number of steps x is equal to or larger than the set value x2 in p13, it is determined in 1) 14 whether the number of steps x is smaller than the set value x3. If the number of steps x is larger than the set value x 3, it is determined to be normal at p20, and the process ends at p16.

In p14, check whether the step number X is equal to the setting value x 3 or not.
If it is smaller than 3, it is determined at p15 that the switch is short-circuited, and the process ends at p16.

If the operating point $1 of the switch is open at p12, p17
It is determined whether or not the number of steps xtfi is larger than the set value x4. If the number of steps X is larger than the set value x4, the process advances to p19. If the number of steps X is smaller than the set value x4, it is determined in ρ18 whether the step number x is smaller than the set value x1.

If the number of steps x is larger than the set value x1, it is determined that the process is normal at p20, and the process ends at p20. Also, if the number of steps × is smaller than the set value × 1, p19
It is determined that it is an oven, and the process ends at p20.

As shown in Fig. 3, if the number of steps of the step motor is within the range of set value x 2 to x 3 according to the control program described above, and the switch operating point S+ and S2 are closed, the switch is short-circuited. If this is diagnosed and the switch operating points S+ and S2 are open outside the range where the number of steps is set value x 1 to x 4, the switch is open (circuit remains cut off or contact is poor). The switch is diagnosed and an alarm is activated to notify the driver of the switch failure.

Note that the above control program is executed repeatedly,
If the alarm is driven based on the diagnosis results a predetermined number of times, rather than on the diagnosis result of one time, it is possible to eliminate erroneous diagnosis due to temporary poor contact.

As described above, in the present invention, the accelerator pedal and the throttle valve are mechanically separated, and the throttle valve is opened and closed by a signal from an electronic control device based on a signal from an accelerator sensor that detects the amount of operation of the accelerator pedal. Since the step motor is driven, the throttle valve can be controlled (1a) independently of the amount of operation of the accelerator pedal during speed change operation, and the switch with operating points S+ and S2 that regulates the operating range of the step motor Since failures are constantly diagnosed, abnormal throttle valve operation due to switch failure can cause the engine to become uncontrollable.
It is possible to prevent accidents such as hindering smooth operation of the transmission or causing the vehicle to run out of control.

In addition, in the above-mentioned embodiment, the operating point of the switch is S+, 8
2 is a throttle valve that closes at the idle position and the fully open position and opens at the intermediate position, but this can also be used with a switch that operates in the opposite manner by reversing the operation.

In the above embodiment, a gasoline engine was described, but the present invention can also be applied to a control device for a diesel engine. In this case, the step motor operates the control lever of the fuel injection pump. Configure.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of an automatic gear shift operating device, Fig. 2 is a hydraulic circuit diagram of a clutch actuator, and Fig. 3 is an operation of a switch that regulates the operating range of a throttle valve driven by a step motor according to the present invention. FIG. 4 is a flowchart illustrating software for diagnosing faults in the same switch. 15: Accelerator sensor 16: Accelerator pedal 21: Synchronous mesh transmission 31: Hydraulic pump 42: Valve shaft 43
: Throttle valve 44: Intake pipe 48: Link 50: Arm 5
1 step motor 52: Operating lever 53: Spring
54: Drive lever patent applicant Isuzu Motors Co., Ltd. Patent applicant Fujitsu Ltd. 17-

Claims (1)

[Claims] The first switch is switched depending on the signal from the accelerator sensor that detects the operating position of the accelerator pedal, and the idle position and maximum fuel position of the throttle valve of the carburetor or the control lever of the fuel injection pump. A step motor connected to the throttle valve or the control lever is driven by an output signal of an electronic control unit which receives a signal from a switch having a second operating point as an input, and the electronic control unit A counter is provided to count the number of operating steps of the step motor, the count is set to O in a non-excited state, and a set value set in advance as an idle position is stored, and the throttle valve or control lever is moved in the fuel increase/decrease direction. 1
Each time the step is sent, the number of steps is counted by ±1, the stored value of the previous idle position is updated to the number of steps when the operating point of the first switch changes, and the difference between this stored value and the counted value is calculated. In a fuel control device for an internal combustion engine in which the throttle valve or control lever is driven in proportion to , a second setting value that is larger by a predetermined number, a third setting value that is smaller by a predetermined number than the number of steps at which the second operating point of the switch switches, and a third set value that is larger by a predetermined number. 4, the operating state of the switch outside the interval between the first set value and the fourth set value, and the interval between the second set value and the third set value. 1. A method for diagnosing a failure of a fuel control device in an internal combustion engine, comprising diagnosing whether the switch is open or showing 1 based on the operating state of the switch inside the switch.