JPH1122529A - Control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give a failure waning to a driver even when a warning means fails without unnecessarily increasing the occasion to limit the engine output by using the warning by the warning means via light or sound at the time of a failure. SOLUTION: Whether a component or a portion related to engine control fails or not is diagnosed by a diagnostic means 52, and a means 51 giving a warning to a driver via light or sound at the time of a failure is operated by an operating means 53 based on the diagnosis result. Whether the operating means 53 or the waning means 51 fails or not is diagnosed by a diagnostic means 54, and the engine output is limited by an engine output limiting means 55 when a component or a portion related to engine control fails and the operating means 53 or the warning means 51 fails based on the diagnosis result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine, and more particularly to a control at the time of failure.

[0002]

2. Description of the Related Art When a failure occurs in a part or a part related to engine control during a normal operation, a method has been proposed in which a fail-safe function is activated (Japanese Patent Laid-Open No. 6-1).
08906).

[0003]

By the way, when a failure occurs in a part or a part related to engine control during normal operation, a warning lamp may be turned on to notify the driver of the failure. In this case, the failure also occurs in the warning light and the lighting circuit (or blinking circuit) of the warning light. If the failure causes the warning light not to light up, there is a failure in parts or parts related to engine control. Cannot even alert the driver.

On the other hand, when a failure occurs in a part or a part related to the engine control, the engine output is limited (for example, fuel cut at a predetermined rotational speed or more), and a change in the engine behavior due to the output limitation causes the driver to fail. It is also possible to inform. However, there are various failures of parts and parts related to engine control.Therefore, it is inconvenient to limit the output even if it is a minor failure or a failure that does not directly affect the basic function of the engine. More opportunities to drive.

[0005] For example, there is one that controls the opening degree of a throttle valve by using an electric motor independently of the depression amount of an accelerator pedal. In this case, two sensors for detecting the depression amount of an accelerator pedal are provided. However, just because one of them failed (slight failure)
For the time being (ie, until the other one fails), the same operation as in normal operation is possible. Therefore, if the output is limited when one of the accelerator pedal sensors fails, the output is unnecessarily limited.

[0006] Even if a failure occurs in the diagnostic function or the fail-safe function (a part that does not directly affect the basic function of the engine), the same operation as in normal operation is possible as long as the failure does not occur in the object to be diagnosed. Therefore, even if the output is limited when a failure occurs in the diagnostic function or the fail-safe function before the failure to be diagnosed, useless output restriction is performed.

In view of the above, the present invention provides an alarm to a driver by means of light or sound when a part or a part related to engine control fails, so that the engine output is not limited, and a diagnostic function of the warning means is added. By limiting the engine output at the time of failure of parts or parts related to engine control and when the warning means is also at fault, while preventing unnecessary increase in the opportunity to limit engine output at the time of failure, It is another object of the present invention to provide a failure alarm to a driver even when a warning means fails.

[0008]

According to a first aspect of the present invention, as shown in FIG. 7, a means 51 for warning a driver by light or sound and a diagnosis as to whether a failure has occurred in parts or parts related to engine control. Means 52 for activating the warning means 51 in the event of failure based on the result of the diagnosis.
A means 54 for diagnosing whether or not a failure has occurred in the operating means 53 or the warning means 51; and based on a result of the diagnosis, when the operating means or the warning means has failed and when a component or part related to the engine control has failed. Means 55 for limiting the engine output.

According to a second aspect, in the first aspect, the failure of a part or a part related to the engine control is a minor failure.

According to a third aspect of the present invention, in the first aspect, the failure of a portion related to the engine control does not directly affect the basic performance of the engine.

According to a fourth aspect, in the third aspect, a portion which does not directly affect the basic performance of the engine is a diagnostic function.

In a fifth aspect of the present invention, in the fourth aspect, the diagnostic function is a diagnostic function of a monitoring IC for a CPU.

According to a sixth aspect, in the third aspect, a portion which does not directly affect the basic performance of the engine is a fail-safe function.

In a seventh aspect, in any one of the first to sixth aspects, the engine output is limited by fuel cut.

In an eighth aspect of the present invention, as shown in FIG. 8, in any one of the first to seventh aspects, a throttle valve 62 driven by an electric motor 61 and an opening degree of the throttle valve 62 are detected. Means 63 and accelerator pedal 6
And means for controlling the electric motor 61 such that the detected throttle valve opening coincides with a target throttle valve opening corresponding to the accelerator pedal depression. 65.

According to a ninth aspect, in the eighth aspect, the restriction of the engine output is to restrict the throttle valve opening target value.

According to a tenth aspect, in the ninth aspect, the restriction of the throttle valve opening target value is that the accelerator pedal depression amount is limited to an upper limit value when the accelerator pedal depression amount is equal to or more than a predetermined value.

In the eleventh invention, the restriction of the throttle valve opening target value in the ninth invention makes the characteristic of the throttle valve opening target value with respect to the accelerator pedal depression amount more gradual than when the engine output is not restricted. It is to be.

[0019]

According to the first aspect of the present invention, the failure diagnosis means
When a failure is diagnosed in a part or a part related to the engine control, a warning is given to the driver by activating a warning means by light or sound.

If the failure is particularly mild or in a part that does not directly affect the basic function of the engine,
The warning by light or sound alone is sufficient, and the engine output is not limited, so that the opportunity to limit the engine output is not unnecessarily increased.

On the other hand, if only the warning means using light or sound is activated at the time of failure diagnosis by the failure diagnosis means, the warning means to the driver is lost when a failure occurs in the warning means.

On the other hand, in the first invention, in this case (that is, when the warning means is desired to be activated but the warning means is not activated), the warning means diagnosing means diagnoses the failure as a failure. The accompanying change in the behavior of the engine informs the driver that there is a malfunction.

As described above, according to the first aspect of the present invention, when a minor failure or a failure of a portion that does not directly affect the basic function of the engine is given, only a warning by light or sound is given. Even if the warning means by light or sound fails and a warning cannot be made, a warning can be reliably issued by another method.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes an ECM (Electronic Control Module) for engine control, which mainly comprises a CPU 2, a memory 3, and an input / output device 4. Among them, the CPU 2 receives signals from various sensors 11. The fuel injection pulse width corresponding to, for example, the intake air amount, the engine speed, and the coolant temperature is calculated based on the fuel injection pulse width, and the fuel corresponding to the fuel injection pulse width is supplied at a predetermined timing from the injector 12 provided in each cylinder. As described above, the fuel control is performed, and the optimum ignition timing is calculated based on the engine speed and load mainly at the time of idling, and at the time of idling, according to the engine speed. The ignition timing is controlled using a REF signal (rising at a predetermined crank angle before the compression top dead center) so as to cut off the ignition timing. The CPU 2 also controls components (eg, a crank angle sensor,
In addition to diagnosing whether a failure has occurred in the air flow meter and its respective signal systems) and parts, the CPU by the monitoring IC 5
It also diagnoses whether a failure has occurred in the diagnostic function.
The monitoring IC 5 monitors the period of a certain pulse from the CPU 2, and when diagnosing that a failure has occurred in the CPU 2 based on the pulse, sends a reset signal to the CPU 2. The monitoring IC 5 has a so-called watchdog timer function.
By fixing the ignition timing and the fuel injection pulse width to fixed values, even when the CPU 2 is out of order, it is possible to perform only the minimum traveling.

It is conceivable to turn on (or flash) a warning lamp to notify the driver of a failure in a part or part related to the engine control when the failure occurs. In this case, the failure also occurs in the warning light and the lighting circuit of the warning light.If the warning light does not light due to the failure, the driver can be alerted even if a failure occurs in parts or parts related to engine control. Can not.

On the other hand, it is conceivable to limit the engine output when a failure occurs in parts or parts related to engine control and notify the driver of the failure by a change in the engine behavior due to the limitation of the output. Even if a failure occurs in the diagnostic function of the monitoring IC 5, the same operation can be performed as in the normal case if the failure does not occur in the CPU 2, and the output is limited only at the time when the failure occurs in the diagnostic function of the monitoring IC 5. In this case, unnecessary output restriction is performed.

In order to cope with this, in the first embodiment of the present invention, when a component or a part related to engine control fails, a warning light is used only to warn the driver, and the engine output is not limited. The diagnostic function of the lamp lighting circuit is added, and the engine output is limited only when the parts or parts related to the engine control have failed and the warning lamp or the warning lamp lighting circuit has also failed.

For this reason, as shown in FIG.
1 is provided in the driver's cab, and a warning light lighting unit 22, a warning light diagnosis unit 24, which receives a signal from the failure diagnosis unit 23, and A
An ND circuit 25 and an engine output limiting unit 26 are newly provided in the ECM1.

First, the warning light lighting section 22 comprises a power transistor 31 as shown in FIG. 3, and when the signal from the CPU 2 is at a low level (there is a light-off request), the warning light 21 is turned on.
When the signal from the CPU 2 becomes high level (there is a lighting request), the power transistor 31 conducts, and the current from the battery 32 flows to the warning lamp 21 to light up.

In FIG. 3, the power transistor 3
One collector is grounded via a large resistor 34, and the potential of the collector is input to the CPU 2 via the input IC 33. The input IC 33 and the resistor 34 constitute a part of a warning light diagnosis unit. The warning light diagnosis unit 24 converts a voltage signal input through the input IC into a lighting circuit mainly including the warning light 21 and the power transistor 31. Diagnose whether a failure such as disconnection or short circuit has occurred. For example, CPU2
Failures that turn off when there is a request for lighting (short-circuit of battery 32, always-off failure of power transistor 31, disconnection, burnout) and failures that turn on when there is a request for turning off CPU2 (for example, ground short-circuit) , The power transistor 31 is always ON), and in these cases, it is determined that a failure has occurred in the warning lamp 21 or the lighting circuit mainly including the power transistor.

Returning to FIG. 2, the failure diagnosis unit 23 diagnoses whether or not a failure has occurred in a part (for example, a crank angle sensor, an air flow meter or its respective signal system) or a part related to engine control during operation, as in the prior art. In addition, C
It is also determined whether a failure has occurred in the diagnostic function of the monitoring IC 5 for the PU 2.

In the AND circuit 25 to which the signal from the failure diagnosis unit 23 and the signal from the warning light diagnosis unit 24 are input, when the failure diagnosis unit 23 determines that there is a failure, and when the warning light diagnosis unit 24 also detects the failure, A high-level signal is output only when it is determined that there is, and a low-level signal is output otherwise.

The engine output limiting section 26 does not limit the output when the signal from the AND circuit 25 is at a low level, but performs fuel cut when the signal from the AND circuit 25 is at a high level. For example, when the rotation speed exceeds a predetermined value 1, fuel cut is performed, and when the rotation speed drops to a predetermined value 2 or less, the fuel is recovered from the fuel cut. Here, as the predetermined value 1, a rotation speed at which traveling is possible is selected.

In FIG. 2, the failure diagnosis unit 23, the warning light diagnosis unit 24, and the engine output control unit 26 are shown by blocks. These functions and the function of the AND circuit 25 are easily expressed by a flowchart. It goes without saying that it can be done.

Here, the operation of the present embodiment will be described.

When the failure diagnosis section 23 diagnoses that the diagnosis function of the monitoring IC for the CPU 2 has a failure, the warning lamp 21 is turned on to give an alarm to the driver.

Here, the diagnostic function of the monitoring IC is a part that does not directly affect the basic function of the engine. When this part fails, only the warning by the warning light is used, and the engine output is not limited. There is no needlessly increased opportunity to limit. On the other hand, if the configuration is such that the warning light is only lit at the time of the failure diagnosis by the failure diagnosis unit 23, when a failure occurs in which the warning light is not lit, the warning means by the light to the driver is lost.

On the other hand, in the embodiment, in this case (that is, when the lighting is requested but the lighting is not performed), the warning light diagnostic unit 24 diagnoses the failure as a failure.
It is reported that the driver has a failure due to a change in the engine behavior due to the output limitation. In other words, even when the warning light cannot be turned on when it is desired to turn on the warning light, it can be warned by another method in this embodiment.

FIG. 4 shows a second embodiment, which corresponds to FIG. 2 of the first embodiment. The same parts as those in FIG. 2 are denoted by the same reference numerals.

When the throttle valve is driven by an electric motor and the amount of drive to the electric motor is controlled in accordance with the amount of depression of the accelerator pedal, the actual throttle valve opening is detected, and this is used to detect the actual throttle valve opening. Since the throttle valve needs to be controlled so as to coincide with the target value of the throttle valve opening corresponding to the depression amount, a throttle sensor is provided in the throttle valve. This throttle sensor output is
As shown in FIG. 5, when the voltage was initially A at the fully closed position of the throttle valve, an error of ΔV occurs when the voltage is shifted to the voltage B due to the deterioration with time. In this case, a value obtained by subtracting the learning value from the throttle sensor output at the time of starting is used as the throttle sensor output to cope with the deterioration with time occurring in the throttle sensor. It should be noted that FIG. 5 shows ΔV in an enlarged manner compared to the actual case. Although FIG. 5 shows the case where the throttle sensor output is increased due to aging, the throttle sensor output may be reduced. In this case, it is needless to say that the learning value is introduced to cope with the aging caused in the throttle sensor. .

The second embodiment presupposes such an electric throttle valve control device. In FIG. 4, a failure diagnosis section 41 includes the learning value described above in addition to the failure diagnosis described in the first embodiment. Diagnose if there is any abnormality.
As a result, the AND circuit 25 outputs a high-level signal only when it is diagnosed that the learning value is abnormal and the warning light diagnostic unit 24 also diagnoses that there is a failure. The unit 42 limits the throttle valve opening target value to the upper limit value when the accelerator pedal is depressed by a predetermined amount or more, as shown by the broken line in FIG. Alternatively, as shown by the one-dot chain line in FIG. 6, the slope of the throttle valve opening target value with respect to the accelerator pedal opening is made gentler than when the engine output is not limited (see the solid line). Instead of limiting the throttle valve opening target value, the engine output may be limited by fuel cut, as in the first embodiment.

Also in the second embodiment, when the abnormality of the learning value is diagnosed, the warning light is only used to warn the driver and the engine output is not limited. Therefore, the opportunity for limiting the engine output is not increased unnecessarily. In addition, even when a warning cannot be issued due to a failure, an alarm can be reliably issued by another method.

In the two embodiments, the diagnostic function and the learning value of the monitoring IC are described as the parts that do not directly affect the basic performance of the engine. However, even if other diagnostic functions (or fail-safe functions) or other minor failures occur. I don't care.

In the embodiment, the warning light has been described, but a warning buzzer may be used.

In the embodiment, the case where the failure of the part related to the engine control does not directly affect the basic performance of the engine has been described, but the failure of the part or the part related to the engine control is a minor failure. The present invention can also be applied to For example, there is one that controls the throttle valve opening degree using an electric motor independently of the accelerator pedal depression amount. When two sensors for detecting the accelerator pedal depression amount are provided in this device, Is a minor failure.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ECM1.

FIG. 2 is a block diagram of an ECM 1 according to the first embodiment.

FIG. 3 is a circuit diagram of a warning light.

FIG. 4 is a block diagram of an ECM 1 according to a second embodiment.

FIG. 5 is a characteristic diagram of the throttle sensor output of the second embodiment.

FIG. 6 is a characteristic diagram of a throttle valve opening target value with respect to an accelerator pedal depression amount according to the second embodiment.

FIG. 7 is a diagram corresponding to the claims of the first invention.

FIG. 8 is a diagram corresponding to a claim of the eighth invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ECM 2 CPU 5 Monitoring IC 21 Warning light 22 Warning light lighting part 23 Failure detection part 24 Warning light diagnosis part 25 AND circuit 26 Engine output restriction part 41 Failure diagnosis part 42 Engine output restriction part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 45/00 345 F02D 45/00 345Z G01M 15/00 G01M 15/00 Z

Claims (11)

[Claims] A means for warning a driver by light or sound; a means for diagnosing whether a failure has occurred in a part or a part related to engine control; a means for activating the warning means in the event of a failure based on a result of the diagnosis. Means for diagnosing whether a failure has occurred in the operating means or the warning means; and limiting the engine output when the operating means or the warning means fails and when a part or part related to the engine control fails, based on the diagnosis result. And a control unit for the engine. 2. A failure of a part or a part related to the engine control is a minor failure.
An engine control device according to claim 1. 3. The engine control device according to claim 1, wherein a failure in a portion related to the engine control does not directly affect the basic performance of the engine. 4. The engine control device according to claim 3, wherein the part that does not directly affect the basic performance of the engine is a diagnostic function. 5. The monitoring function according to claim 1, wherein the diagnostic function is a monitoring I
The engine control device according to claim 4, wherein the control device is a diagnostic function of C. 6. The engine control device according to claim 3, wherein the portion that does not directly affect the basic performance of the engine is a fail-safe function. 7. The engine control device according to claim 1, wherein the engine output is limited by a fuel cut. 8. A throttle valve driven by an electric motor, means for detecting the opening of the throttle valve, means for converting the depression amount of an accelerator pedal into an electric signal, and the detected throttle valve opening is The engine control device according to any one of claims 1 to 7, further comprising: means for controlling the electric motor so as to coincide with a throttle valve opening target value corresponding to an accelerator pedal depression amount. . 9. The engine control device according to claim 8, wherein the limiting of the engine output is to limit the throttle valve opening target value. 10. The restriction of the throttle valve opening target value is as follows:
The engine control device according to claim 9, wherein the accelerator pedal depression amount is limited to an upper limit value when the accelerator pedal depression amount is equal to or more than a predetermined value. 11. The restriction of the throttle valve opening target value is as follows:
10. The engine control device according to claim 9, wherein the characteristic of the throttle valve opening target value with respect to the accelerator pedal depression amount is made gentler than when the engine output is not limited.