JPH0774625B2 - Control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to a case where an opening / closing operation of a throttle valve is abnormal.
The present invention relates to a control device for an internal combustion engine that enables traveling while ensuring vehicle safety.

[Conventional technology]

2. Description of the Related Art Conventionally, as a control technique when a drive device for a throttle valve fails, a device for stopping fuel supply to an internal combustion engine when an opening / closing operation of the throttle valve is abnormal is disclosed. (JP-A 61-8436). This technique controls the internal combustion engine so that when the throttle valve is stuck in the open state, the fuel supply to the engine is stopped if the engine speed is higher than a predetermined value so that the engine speed does not become abnormally high. To do.

[Problems to be solved by the invention]

However, since the above-mentioned conventional technique is mainly aimed at preventing engine runaway at the time of failure of the throttle valve and improving safety, a so-called limp home function (function capable of traveling to the nearest service factory even if it fails) It was hard to say that this was taken into consideration. That is, when attempting to limp home by the above-mentioned technique, the engine speed fluctuates greatly across the boundary speed regardless of the driver's will, and falls into a hunting state, resulting in extremely deteriorated drivability. . Alternatively, if the throttle valve is stuck on a climbing plate or the like having a large load, the engine speed does not rise to the boundary speed, which may result in a state where fuel cut is not performed.

It is an object of the present invention to provide a control device for an internal combustion engine that solves the above problems and can improve the limp home function of the vehicle while ensuring vehicle safety.

[Means for solving problems]

The first invention made as a means for achieving the above object is, as shown in FIG. 1, as an example, a throttle valve B for adjusting the amount of air supplied to the internal combustion engine A, and a sticking of the throttle valve B is detected. Abnormality detection means C2
And when the sticking of the throttle valve B is detected, it is determined whether or not the throttle valve B is at or above the operation stop opening, and is at or above the output increase opening smaller than the operation stop opening. The opening degree determination means D2, the operation stop means E2 for stopping the operation of the internal combustion engine A when the throttle valve B sticks above the operation stop opening degree, and the sticking of the throttle valve B When it occurs below the operation stop opening and above the output increase opening, the output of the internal combustion engine A is controlled to be lower than usual, and when the sticking of the throttle valve B occurs below the output increase opening. The gist is a control device for an internal combustion engine, which comprises an output control means F2 for increasing the output of the internal combustion engine A above normal.

The throttle valve B may be, for example, mechanically connected to an accelerator pedal, or may be a linkless type that is controlled based on the opening degree of the accelerator pedal and the running state of the vehicle.

The abnormality detecting means C2 detects, for example, a state in which the throttle valve B is stuck and does not operate, and detects the sticking of the throttle valve B by means such as the following example.

That is, I Based on the deviation between the target throttle opening and the actual throttle opening.

II Based on the change value of the target throttle opening and the change value of the intake air amount.

III Based on the deviation between the operation amount of the accelerator pedal and the actual throttle opening.

In the case of IV linkless throttle valve, it is based on the motor current value.

The operation stopping means E2 may stop the operation of the internal combustion engine by stopping the fuel supplied to the internal combustion engine A, or may also stop the operation of the internal combustion engine by stopping ignition or the like. May be

The output control means F2 increases or decreases the fuel supply amount (controls the air-fuel ratio)
To control the output of the internal combustion engine A, or to control the output of the internal combustion engine A by increasing or decreasing the EGR amount. In addition, for controlling the advance angle of the ignition timing or the idle speed control, Alternatively, the valve opening control of the bypass passage may be performed.

[Action]

In the control device for an internal combustion engine according to the present invention, the abnormality detecting means C2 detects sticking of the throttle valve B, and if the opening degree of the throttle valve B at the time of detecting the sticking is equal to or more than the operation stop opening degree, the abnormal opening degree judging means. When D2 determines, the operation stopping means E2 stops the operation of the internal combustion engine A, while the opening of the throttle valve B at the time of detecting the sticking is abnormally opened if the opening is less than the operation stop opening and more than the output increase opening. When the degree determination means D2 makes a determination, the output control means F2 controls the output of the internal combustion engine A by suppressing the output more than usual, and when the opening of the throttle valve B is less than the output increase opening, the output control means The output of the internal combustion engine A is made larger than usual by F2.

〔Example〕

 Each embodiment of the control device for an internal combustion engine of the present invention will be described.

As shown in FIG. 2, the system to which this embodiment is applied is an internal combustion engine (hereinafter referred to as an engine) I, the engine 1
The throttle valve 3 for adjusting the intake amount of the engine, the throttle valve control device 5 for controlling the throttle valve 3, the fuel supply amount and the exhaust gas recirculation amount of the engine 1 (hereinafter referred to as EG
The engine control device 7 is provided for controlling the R amount) based on the operating state.

The engine control device 7 is composed of an input / output interface 9, a central processing unit 11, a storage unit 13 and the like, and operates as follows. That is, the operating state of the engine 1 is input to the central processing unit 11 via the input / output interface 9, and the fuel injection amount and EG are calculated based on the programs and data stored in the storage unit 13 in advance.
The central processing unit 11 calculates the R amount, and according to the calculated value,
A control signal is output via the input / output interface 9 to the modulator 19 that controls the valve opening of the fuel injection valve 15 that supplies fuel to the engine 1 and the EGR valve 17. By outputting the control signal to each unit, the engine control device 7 optimally controls the fuel state of the engine 1. In addition,
The details of the control of the fuel injection valve 15 and the modulator 19 are well known in the art, and thus the description thereof is omitted here.

Like the engine control device 7, the throttle valve control device 5 includes an input interface 21, a central processing unit 23, a storage unit 25, and the like, and performs the following operation.

(1) Intake air amount sensor 27 for detecting the intake air amount, throttle opening sensor 31 for detecting the opening of the throttle valve 3,
A rotation speed sensor 33 that detects the rotation speed of the engine 1, and a water temperature sensor that detects the cooling water temperature (engine water temperature) of the engine 1
A process of inputting the detected values of the accelerator operation amount sensor 39 for detecting the operation amount of the accelerator pedal 37 and the accelerator pedal 37 to the central processing unit 23 via the input / output interface 21.

(2) Based on the input data, the opening of the throttle valve 3 (throttle opening) is calculated based on a program and data, etc., which will be described later and stored in the storage unit 25, and the opening / closing of the throttle valve 3 is calculated. The process of determining valve operation abnormality, determining ERG supply stop, and determining fuel supply amount.

(3) According to the determination, the EGR stop valve 41 for stopping the EGR supply, the throttle actuator 29 that drives the throttle valve 3, and the control signals to the engine control device 7 are output through the input / output interface 21. Thus, the process of executing the opening control of the throttle valve 3 and the output control of the engine 1.

The opening control of the throttle valve 3 is executed based on the detected value of the throttle opening sensor 31, the detected value of the accelerator operation amount sensor 39, and the like. For example, the throttle valve control device 5 shown in FIG. 2 has an accelerator operation amount sensor 39, an engine water temperature sensor 35, an engine speed sensor 33, an intake air amount sensor 27 via its input / output interface 21.
The optimum target throttle opening θ0 of the throttle valve 3 is calculated by inputting the detected values such as, and the actual opening θr of the throttle valve 3 (the opening detected by the throttle opening sensor 31) matches the opening θ0. So the throttle actuator 29
To drive. By the way, although the EGR supply is stopped by the EGR stop valve 41 in the present embodiment, an EGR supply stop signal may be output to the modulator 19 as another means. Further, in this embodiment, the input of the engine state to the engine control device 7 is performed by the throttle valve control device 5
This is done through the input / output interface 21 of, but the reverse is also possible. That is, the engine state is input to the engine control device 7, and the input / output interface 9
The engine state may be input to the throttle valve control device 5 through the.

The output control of the engine 1 first detects an abnormality in the opening / closing operation of the throttle valve 3 (FIGS. 3 to 5), and then stops the EGR or changes the basic fuel injection amount (internal combustion engine shown in FIG. 6). Control routine).

First, the abnormality detecting means (lock detecting means) for the operation of the linkless throttle valve will be described with reference to FIGS.

The abnormality detection routine shown in FIG. 3 is executed every 50 msec, for example, separately from the above-mentioned throttle valve opening control.

In the abnormality detection routine of FIG. 3, whether or not it has already been determined that the opening / closing operation of the throttle valve 3 is abnormal is determined by the abnormality flag F (step 100). If the abnormality flag F has already been set, this routine is once terminated, and if the abnormality flag F has not been set, the routine proceeds to step 110. In step 110, the opening difference Δθ between the target opening θ0 of the throttle valve 3 (command value from the throttle valve control device 5 to the throttle actuator 29) and the actual opening θr (detection value of the throttle opening sensor 31) is calculated. calculate. Next, the integrated value θi of the opening difference Δθ
Is calculated (step 120). The integrated value θi is the past 4
The opening difference Δθ calculated in the current process is added to the integral value θi of the opening difference Δθ calculated in the process of this routine. That is, the calculation of θi ← θi + Δθ−Δθ5 is performed (Δθ5 is the value set in the previous step 140). For example, as shown in FIG. 4, when the current processing time is time TF, times TA to TE
Target throttle opening θ0 and actual throttle opening θ
Integrated value of opening difference Δθ from r θi (= ΔθA + ΔθB +
ΔθC + ΔθD + ΔθE) is added to the opening difference ΔθF at the current time TF and the opening difference ΔθA at the time TA is subtracted to calculate the integrated value θi at the current time.

Next, it is determined whether the integrated value θi of the opening difference Δθ is smaller than the lock determination value K (step 130 in FIG. 3). The lock determination value K may be a predetermined value, or may be a function of the engine water temperature, a temperature in the vicinity of the bearing of the throttle actuator 29, an ambient temperature, or the like as shown in FIG. By making it a function of the engine water temperature, etc.,
The lock of the throttle valve 3 can be determined more accurately.

When it is determined that the throttle valve 3 is not locked (θi <K) in the lock determination of the throttle valve 3 in step 130 of FIG. 3, the previous value of the fourth opening difference memory Δθ4 is set. The fifth opening difference memory θ5 (step 140), the previous value of the third opening difference memory Δθ3 is set to the fourth opening difference memory Δθ (step 150), and the previous value of the second opening difference memory Δθ2 is set. The third opening difference memory Δθ3 (step 160), the previous value of the first opening difference memory Δθ1 to the second opening difference memory Δθ2 (step 170), and the current opening difference Δθ to the first opening difference In memory Δθ1 (step 18
0) Set. This makes it possible to use the value of the fifth opening degree difference memory Δθ5 set in step 140 for the calculation performed in step 120.

As a result of the above processing of steps 100 to 180, it is determined in step 130 that the throttle valve 3 is locked (θi ≧
If K), the abnormality flag F is set (step 190). This abnormality flag F is used to detect the locked state of the throttle valve in the control routine of the internal combustion engine of FIG.

Next, an embodiment of the present invention will be described. This embodiment is carried out by monitoring the set state of the abnormality flag F in the abnormality detection routine of FIG. 3 and executing the control routine of the internal combustion engine of FIG. 6 for changing the basic fuel injection amount. In this routine, first, the set state of the state abnormality flag F is checked to determine whether the throttle valve 3 is in an abnormal (locked) state (step 200). When it is determined that the throttle valve 3 is abnormal, the opening degree θ of the throttle valve 3 is equal to or larger than the operation stop opening degree θ3 (here, 30 °) based on the detection value of the throttle opening sensor 31. Is determined (step 210), θ ≧
In the case of θ3, the fuel injection stop signal is output from the throttle valve control device 5 executing this routine to the engine control device 7 controlling the fuel injection amount to supply the fuel to the engine 1. Stop (step 220).

By the steps 200 to 220, when the throttle valve 3 is locked at the operation stop opening θ3 or more, the fuel supply to the engine 1 can be stopped before the engine speed further increases. Therefore, the faucet function for the throttle valve 3 is improved.

If it is determined in step 210 that the throttle opening θ is less than the operation stop opening θ3, the process proceeds to the next determination of the abnormal opening (step 230). In step 230, whether the abnormal opening is less than the operation stop opening θ3 and the output decreasing opening θ2 or more (θ2 ≦ θ <θ3), or the output decreasing opening θ2 is less than the output increasing opening θ1 or more. Or (θ1 ≦
θ <θ2) is determined and, based on the determination, the process is shifted to any of the next output control steps 240 to 260 of the engine 1.

When it is determined that the abnormal opening is within the range of θ2 ≦ θ <θ3 (here, θ2 is 20 °), the engine control unit 7
A fuel injection amount decrease signal is output to reduce the engine output (step 240). The fuel injection amount may be set to, for example, an air-fuel ratio at which the engine 1 can operate without misfiring, for example, 0.7 times the basic injection amount, or the basic injection amount may be decreased based on the throttle opening θ. . By reducing the basic injection amount based on the throttle opening θ, the engine output can be controlled with high accuracy.

By the processing of steps 200, 210, 230, and 240, when an abnormality occurs when the throttle opening θ is relatively large, that is, when the throttle valve 3 is locked in a state where a large engine output is generated, the fuel supply amount to the engine 1 is changed. The engine output can be reduced by reducing the amount. Therefore, even if the throttle valve 3 is locked at a relatively large throttle opening, the execution of this processing will result in
Since the engine output can be reduced, the vehicle can be safely driven by operating the clutch and the brake.

The abnormal opening of step 230 is θ1 ≦ θ <θ2 (where θ1
When it is judged that the basic injection amount control signal is output to the engine control device 7 as it is (step 250). As a result, the output of the engine 1 is controlled to a value calculated without an increase / decrease command for the injection amount from the throttle valve control device 5.

By the processing of steps 200, 210, 230, and 250, the current engine output can be maintained when the throttle opening θ in which the abnormality has occurred is the opening that produces an engine output that allows emergency travel.

When it is determined in step 230 that the abnormal opening is within the range of θ <θ1, a signal for instructing the engine control device 7 to increase the basic injection amount and a signal for driving the EGR stop valve 41 are sent. Output (step 260). As a result, the output generated by the engine 1 can be increased.

By the processing of steps 200, 210, 230, and 260, when an abnormality occurs with a small slot opening θ, the engine output can be increased to a travelable output of the vehicle to drive the vehicle.

As described above, according to this embodiment, by stopping or reducing the fuel supply to the engine 1 in accordance with the abnormality opening degree (lock opening degree) of the throttle valve 3, the engine corresponding to the abnormality occurring opening degree. Output characteristics can be obtained. Therefore, when the opening is such that the output of the throttle valve 3 cannot be reduced to a proper value other than limiting the intake air amount (operation stop opening θ3 or more), the operation of the engine 1 is stopped and It has the excellent effect of avoiding broadcasts, etc. and greatly improving its safety.

On the other hand, when the throttle valve 3 is locked below the operation stop opening θ3 and above the output decreasing opening θ2, the engine output is controlled by decreasing the fuel injection amount,
It is possible to drive a minimum of vehicles,
It has an excellent effect of improving the so-called limp home function.

Moreover, when the throttle valve 3 is locked at an extremely small output increase opening (less than the throttle opening θ1), the engine output can be increased and the engine output can be increased to a value at which the vehicle can travel.

As a result, according to the embodiment of the present invention, the limphole function can be further improved.

The present invention is not limited to the above embodiment,
Examples of various aspects are possible within the scope of the present invention.

〔The invention's effect〕

When the output of the internal combustion engine is too large and safe operation cannot be performed by the vehicle's brakes and clutches, stop the operation of the internal combustion engine when the opening / closing operation of the throttle valve is abnormal at a throttle opening. Because you can
It has an excellent effect that a high fail-safe function can be obtained while maintaining the limp home function of the vehicle.

Furthermore, when the throttle valve locks at a relatively large opening, it is possible not only to safely drive the vehicle by reducing the engine output, but also when the throttle valve locks at an extremely small opening. In addition, the engine output can be increased to a value at which the vehicle can travel, and thereby the limp home function can be further improved by the output control of the internal combustion engine in the output control means.

Therefore, the control device for an internal combustion engine according to the present invention has an extremely excellent effect capable of sufficiently improving the fail-safe and limp home functions of the vehicle.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a basic configuration of the present invention, FIG. 2 is a configuration diagram of an embodiment to which the present invention is applied, FIG. 3 is a flowchart of an abnormality detection routine of the embodiment, and FIG. FIG. 5 is a graph showing an opening / closing valve control characteristic of an example throttle valve, FIG. 5 is a characteristic graph of a lock determination value K of the embodiment, FIG. 6 is a flow chart of a control routine of an internal combustion engine of the embodiment, and FIG. It is a graph of an engine output characteristic. A ... Internal combustion engine, B ... Throttle valve, C2 ... Abnormality detection means, D2 ... Abnormal opening determination means, E2 ... Operation stop means, F2 ... Output control means, 1 ... Engine, 3 ... Throttle valve, 5 ... Throttle valve control device, 7 ...
… Engine control device, 15 …… Fuel injection valve, 41 …… EGR stop valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 61-175250 (JP, A) JP 59-122742 (JP, A) Actual development 60-49235 (JP, U)

Claims (4)

[Claims] 1. A throttle valve for adjusting the amount of air supplied to an internal combustion engine, an abnormality detecting means for detecting sticking of the throttle valve, and a stop of the throttle valve when sticking of the throttle valve is detected. An abnormal opening determination means for determining whether the opening is equal to or larger than the opening, or an output increase opening smaller than the operation stop opening, and the sticking of the throttle valve occurs above the operation stop opening. When the operation stop means for stopping the operation of the internal combustion engine, and when the sticking of the throttle valve occurs below the operation stop opening and above the output increase opening, the output of the internal combustion engine is set higher than usual. Output control means for suppressing and controlling, and when the sticking of the throttle valve occurs below the output increasing opening degree, the output of the internal combustion engine is made larger than usual. Control system for an internal combustion engine having. 2. The output control means, when the sticking of the throttle valve is less than the operation stop opening, less than the output increasing opening, less than the output decreasing opening, and more than the output increasing opening, The control device for an internal combustion engine according to claim 1, which does not suppress the output of the internal combustion engine. 3. The output control means according to claim 1, wherein at least one of a fuel supply amount, an ignition timing, and an exhaust gas recirculation amount is controlled in accordance with an opening degree of the throttle valve. A control device for an internal combustion engine as described. 4. The abnormality detecting means detects abnormality when the integrated value of the deviation between the target opening and the actual opening of the throttle valve is equal to or more than a predetermined value.
The control device for an internal combustion engine according to any one of the items.