JP2003222033A - Throttle controller of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the suppression of an engine output accompanied by conducting fail-safe by keeping a regular throttle opening control as long as possible when an abnormality of an A/D converter is detected. <P>SOLUTION: On the regular throttle opening control, an analog signal from different kinds of sensors is converted into a digital signal with the A/D converter 6, and an accelerator depressing amount and the throttle opening are calculated from the signal after being converted. The opening of a throttle valve 3 is regulated by driving a motor 4 based on the opening demand calculated from these. When the abnormality of the A/D converter 6, the A/D converter 6 is reset, and thereafter when the opening demand value is not greater than the predetermined value K, the opening control of the throttle valve 3 is permitted based on the opening demand under the condition that the abnormality of the A/D converter 6 does not appear. Under the condition other that it, such a fail-safe action that restricts the opening change toward the opening side of the throttle valve 3 is carried out. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle control device for an internal combustion engine used as a prime mover for automobiles and the like.

[0002]

2. Description of the Related Art In recent years, as a throttle valve for an internal combustion engine for an automobile, an electronically controlled throttle valve as shown in, for example, Japanese Patent Laid-Open No. 61-229949 has been put into practical use. The opening control of such an electronically controlled throttle valve is performed, for example, in the procedure shown in [1] and [2] below.

[1] Analog signals from various sensors such as an accelerator position sensor for detecting the accelerator pedal depression amount (accelerator depression amount) and a throttle position sensor for detecting the throttle valve opening (throttle opening) It is converted into a digital signal by the / D converter.

[2] The microcomputer determines the opening command value of the throttle valve from the digital signal, and drives and controls the motor based on the opening command value to adjust the opening of the throttle valve.

By the way, when any abnormality occurs in the A / D converter during the opening control of the throttle valve as described above, the analog signals of various sensors are not properly converted into digital signals, and the opening The command value may be inappropriate. If the opening of the throttle valve is adjusted based on this inappropriate opening command value, the opening of the valve becomes inappropriate for engine operation. Therefore, when an abnormality of the A / D converter is detected, it is considered that the fail safe is executed for the throttle valve to limit the change of the throttle valve to the opening side beyond the opening that allows the vehicle to run in the retracted state. .

[0006]

By executing the fail safe as described above, the opening command value becomes an inappropriate value due to the abnormality of the A / D converter, and the opening of the throttle valve of the automobile. It is possible to prevent the driving state from becoming an inappropriate value. However, when fail-safe is executed, the opening degree may be limited even if the opening degree is not limited as described above, which causes the running performance of the vehicle. It was the cause of the decrease.

The present invention has been made in view of the above circumstances, and an object thereof is to continue the normal throttle opening control as much as possible when failing to detect the A / D converter and to fail safe. An object of the present invention is to provide a throttle control device for an internal combustion engine that can minimize the suppression of the engine output due to the execution of.

[0008]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. In order to achieve the above object, in the invention according to claim 1, the analog signal from the sensor is converted into a digital signal by an A / D converter, and the throttle valve of the throttle valve is based on the opening command value obtained from the converted signal. When an abnormality of the A / D converter is detected in the throttle control device of the internal combustion engine that controls the opening degree and performs fail-safe on the throttle valve when the abnormality of the A / D converter is detected If the condition that at least the opening command value is equal to or less than a predetermined opening is satisfied after the A / D converter is reset to the above, the opening control of the throttle valve based on the opening command value is performed. The control means for permitting

According to the above construction, when the abnormality of the A / D converter is detected, the A / D converter is reset to restore the normal state. After the A / D converter is reset, when the opening command value is equal to or less than a predetermined value and the opening command value is unlikely to adversely affect the engine operation, The throttle valve opening control based on the command value is continued. In this way, the normal opening control of the throttle valve is continued as much as possible, and the suppression of the engine output due to the execution of the fail safe can be minimized.

According to a second aspect of the invention, in the first aspect of the invention, the control means resets the A / D converter, and then the opening command value is equal to or less than a predetermined opening. In addition to the condition being satisfied, the opening control of the throttle valve based on the opening command value is permitted under the condition that the abnormality of the A / D converter is not detected.

According to the above construction, the opening control of the throttle valve based on the opening command value after the A / D converter is reset is performed not only when the opening command value is equal to or less than the predetermined opening, but Unless the condition that no abnormality has occurred in the / D converter is not continued. Therefore, A / D
When the abnormality of the A / D converter is detected even after the converter is reset, it is possible to prevent the normal opening control of the throttle valve from continuing.

According to the invention of claim 3, claim 1 or 2
In the invention described above, the control device resets the A / D converter and then, when the condition that the opening command value is equal to or less than the predetermined opening is not satisfied, the throttle valve is used as the fail safe. The change in the opening degree of the open side is limited.

According to the above configuration, after the A / D converter is reset, the opening command value is larger than the predetermined value (open side), and the opening command value is temporarily set for engine operation. When it is highly possible that the engine operation is adversely affected when the value is inappropriate, the normal throttle valve opening control is stopped and the fail safe is executed. Therefore, it is possible to appropriately execute fail-safe when necessary, and to prevent the opening of the throttle valve from being excessively opened from the proper state.

According to the invention of claim 4, claim 2 or 3
In the invention described above, the control device may perform the A / D converter reset operation even when the condition that the opening command value is equal to or less than a predetermined opening is satisfied. On the condition that the abnormality of the / D converter is detected, the change in the opening of the throttle valve toward the opening side is limited as the fail safe.

According to the above construction, after the A / D converter is reset, even if the opening command value is equal to or less than the predetermined value, if the abnormality of the A / D converter is detected, the fail safe condition is detected. Is executed. Therefore, when the abnormality of the A / D converter is detected even after the A / D converter is reset, the fail-safe is appropriately executed and the opening of the throttle valve is excessively opened from the proper state. Can be suppressed.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the control device detects an abnormality of the A / D converter after the fail-safe is executed. The same fail-safe will be continued regardless of the presence or absence.

According to the above configuration, since the normal throttle valve opening control is not executed after the fail-safe is executed, the throttle valve opening control based on an inappropriate opening command value is performed. Therefore, it is possible to accurately avoid the occurrence of a problem.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to an automobile engine will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a schematic diagram showing the configuration of the throttle control device of this embodiment. Engine 1 shown in this figure
In the above, the engine output is adjusted by opening and closing the throttle valve 3 provided in the intake passage 2 by driving the motor 4 and changing the intake air amount of the engine 1.

Further, the throttle control device for the engine 1 includes: a micro-computer (an electric slot microcomputer) 5 for controlling the opening of the throttle valve 3, and an A / which converts analog signals output from various sensors into digital signals. D converter 6, · Performs various engine controls such as fuel injection control and ignition timing control of the engine 1 and monitors the A / D converter 6 for any abnormalities. A resetting microcomputer (control / monitoring microcomputer) 7 and the like are provided.

The electric slot microcomputer 5 and the control / monitor microcomputer 7 are communicable with each other, and each of them is an A / D.
It is connected to the converter 6. In this A / D converter 6,
A throttle position sensor 8 for detecting the opening degree of the throttle valve 3 (throttle opening degree), an accelerator position sensor 10 for detecting the depression amount (accelerator depression amount) of an accelerator pedal 9 operated by a driver of an automobile, and the like. Various sensors are connected.

The A / D converter 6 has a plurality of channels for converting an analog signal into a digital signal (A / D conversion), and each of the channels corresponds to each of various sensors. There is. Then, when the opening control of the throttle valve 3 by the electric slot microcomputer 5 and the engine control by the control / monitoring microcomputer 7 are performed, those microcomputers 5, 7
Therefore, the A / D converter 6 is required to perform A / D conversion for a predetermined channel required for each control described above.

For example, when controlling the opening of the throttle valve 3, the electric slot microcomputer 5 requests the A / D converter 6 to perform A / D conversion for the channel corresponding to the accelerator position sensor 10. A / D conversion for the channel corresponding to the throttle position sensor 8 is also required. When A / D conversion is requested in this way, the A / D converter 6 converts the analog signal from the accelerator position sensor 10 and the throttle position sensor 8 into a digital signal, and the converted signal is converted into the A / D signal. The data is output to the microcomputer requesting the conversion (in this case, the electric slot microcomputer 5).

In the electric slot microcomputer 5, as described above,
The accelerator depression amount and the throttle opening are calculated based on the digital signal after the / D conversion is performed, and the opening command value used for the opening control of the throttle valve 3 is calculated based on them. Then, the electric slot microcomputer 5 controls the motor 4 through the drive circuit 11 based on the opening command value to change the opening of the throttle valve 3 to a value corresponding to the opening command value. By controlling the opening of the throttle valve 3 in this way, the engine output is adjusted according to the driver's output request to the engine 1, that is, the accelerator depression amount.

When controlling the engine such as the fuel injection control and the ignition timing control of the engine 1, the control / monitor microcomputer 7 sends to the A / D converter 6 a channel corresponding to the sensor required for the above control. A / D conversion is required. When the A / D conversion is requested in this way, the A / D converter 6 converts the analog signal from the sensor into a digital signal and outputs the converted signal to the microcomputer that requests the A / D conversion (this In the case, it outputs to the control / monitoring microcomputer 7). The control / monitor microcomputer 7 is an A / D
Various command values used in the engine control are calculated based on the converted digital signal, and engine control such as fuel injection control and ignition timing control is executed based on the command values.

When A / D conversion is performed as described above in controlling the opening of the throttle valve 3 and controlling the engine, A
The A / D converter 6 sends the completion signal corresponding to the completion of the A / D conversion and the channel signal corresponding to the channel on which the A / D conversion is actually performed to the microcomputer requesting the A / D conversion. Output. The A / D converter 6 also outputs a watchdog pulse, which is inverted every predetermined period, to the control / monitoring microcomputer 7. The completion signal, the channel signal, and the watchdog pulse are used when determining whether or not an abnormality has occurred in the A / D converter 6.

Here, how to detect the occurrence of an abnormality in the A / D converter 6 will be described. The abnormality detection of the A / D converter 6 is performed through the electric slot microcomputer 5 and the control / monitoring microcomputer 7.

The electric slot microcomputer 5 inputs the completion signal and the channel signal from the A / D converter 6 as described above when controlling the opening degree of the throttle valve 3. And
Based on the signal, it is judged whether or not the situation is shown in the following [3] and [4], and when it is, the A / D
It is determined that an abnormality has occurred in the converter 6.

[3] A channel for which A / D conversion is requested by the electric slot microcomputer 5 at the time of controlling the opening of the throttle valve 3, and a channel signal from the A / D converter 6 based on the A / D conversion. Does not correspond. That is, the channel that is different from the channel that requested A / D conversion
/ D conversion is being performed.

[4] The completion signal from the A / D converter 6 is not input to the electric slot microcomputer 5 after the A / D conversion.
That is, A / D conversion is not performed by the A / D converter 6. When it is determined that at least one of the above [3] and [4] has occurred and an abnormality has occurred in the A / D converter 6, the electric slot microcomputer 5 reports that an abnormality has occurred. A signal corresponding to the judgment is output to the control / monitor microcomputer 7.

On the other hand, the control / monitor microcomputer 7 inputs a signal corresponding to the judgment from the electric slot microcomputer 5 that the abnormality has occurred, and at the time of engine control such as fuel injection control or ignition timing control, A /
The completion signal and channel signal from the D converter 6 are also input. Then, based on the signal, etc., the following [5] to [8]
It is determined whether or not the situation is as shown in (1) and whether or not some abnormality has occurred in the A / D converter 6 in that situation.

[5] A signal corresponding to the determination of the occurrence of the abnormality is input from the electric slot microcomputer 5. That is, the A / D for controlling the opening degree of the throttle valve 3
At the time of conversion, the occurrence of an abnormality in the A / D converter 6 is detected by the electric slot microcomputer 5.

[6] The channel for which A / D conversion is requested by the control / monitoring microcomputer 7 during the engine control corresponds to the channel signal from the A / D converter 6 based on the A / D conversion. Not not. That is, A / D conversion is performed on a channel different from the channel that has made the A / D conversion request.

[7] The completion signal from the A / D converter 6 is not input to the control / monitor microcomputer 7 after the A / D conversion. That is, A / D conversion is not performed by the A / D converter 6.

[8] The watchdog pulse from the A / D converter 6 to be input to the control / monitor microcomputer 7 is not generated. That is, the function of the A / D converter 6 is stopped.

Based on the fact that at least one of the situations [5] to [8] has occurred, the A / D converter 6
It is determined that an abnormality has occurred in the A / D converter 6, and thus the abnormality occurrence in the A / D converter 6 is detected.

Next, the control of the opening degree of the throttle valve 3 when an abnormality occurs in the A / D converter 6 will be described.
When an abnormality occurs in the A / D converter 6, the signal obtained by the A / D conversion becomes incorrect. Therefore, the accelerator depression amount, the throttle opening, and the opening command value calculated based on the signal become inappropriate values, and when the throttle valve 3 is controlled based on the opening command value, The opening becomes unsuitable for engine operation.

Therefore, when an abnormality in the A / D converter 6 is detected, the opening of the throttle valve 3 is changed to the opening side so that the opening of the throttle valve 3 does not open too much from the proper state. It is conceivable to execute a fail-safe that restricts the evacuation to the extent that the vehicle can be evacuated. Such fail-safe is realized by the control / monitoring microcomputer 7 controlling the motor 4 through the drive circuit 11.

By performing the fail-safe as described above, it is possible to prevent the opening of the throttle valve 3 from reaching a value that makes the traveling state of the vehicle inappropriate. However, the opening degree may be limited even if the opening degree is not limited, which causes a reduction in the running performance of the vehicle.

Therefore, in this embodiment, when an abnormality in the A / D converter 6 is detected, the A / D converter 6 is reset to restore the normal state. Further, when the opening command value is equal to or less than the predetermined value K after the reset and the opening command value has a low possibility of adversely affecting the engine operation, an abnormality of the A / D converter 6 is detected. Throttle valve 3 based on the above opening command value, provided that
Continue to control the opening. In this way, by controlling the opening degree of the throttle valve 3 based on the opening degree command value as usual as much as possible, the suppression of the engine output due to the execution of the fail safe is minimized, and the running performance of the vehicle is deteriorated. Can be suppressed.

Now, the procedure for controlling the opening of the throttle valve 3 when an abnormality occurs in the A / D converter 6 will be described with reference to the flowchart of FIG. This abnormal-time processing routine is executed by the control / monitoring microcomputer 7 by, for example, a time interruption at every predetermined time.

In the abnormality processing routine, it is determined whether or not the abnormality determination flag F2 for determining whether or not the abnormality occurrence is determined in step S101 is "0 (undetermined)". Further, in S102, it is determined whether or not the abnormality occurrence flag F1 for determining whether or not an abnormality has occurred during the current engine operation is "0 (no abnormality)".

When a positive determination is made in both the processes of S101 and S102, it is determined whether or not an abnormality has occurred in the A / D converter 6 according to the procedure described above (S103).
When it is determined that an abnormality has occurred, the A / D converter 6 is reset (S104), and thereby the A / D converter 6 is restored to the normal state. After that, the abnormality occurrence flag F1 is set to "1 (abnormality)" (S105). As described above, at the time when it is determined that an abnormality has occurred in the A / D converter 6 for the first time during the engine operation of this time, that is, when the abnormality occurrence flag F1 becomes "1", a normal operation based on the opening degree command value is performed. The opening degree control of the throttle valve 3 is permitted (S106).

When an abnormality occurs in the A / D converter 6 for the first time during the current engine operation, the abnormality determination flag F2 becomes "0".
(Undetermined) ”and the abnormality occurrence flag F1 becomes“ 1 (abnormality) ”. Therefore, a negative determination is made in step S102, and it is determined whether or not the opening command value is equal to or less than the predetermined value K described above. It is determined (S107). This predetermined value K is A /
Even if the opening degree command value becomes improper due to the abnormality of the D converter 6, it corresponds to the opening degree command value that is unlikely to adversely affect the engine operation.

If the determination in step S107 is affirmative, it means that the opening command value has a low possibility of adversely affecting the engine operating state. Therefore, in this case, on the condition that it is determined that there is no abnormality in the abnormality determination of the A / D converter 6 in the same procedure as above (S108: NO),
The normal opening control of the throttle valve 3 based on the opening command value is permitted (S106). As a result, the opening control of the throttle valve 3 based on the opening command value is executed as usual.

If a negative determination is made in step S107 and there is a high possibility that the engine operating state will be adversely affected when the opening command value is inappropriate, the above-mentioned fail safe is executed (S109). ). Furthermore, even if the positive determination is made in step S107, if it is determined that the A / D converter 6 is abnormal (S108: YES),
Failsafe is executed in the same manner as above (S10).
9).

When the fail-safe is executed in this way, the abnormality confirmation flag F2 is set to "1 (abnormality confirmation)" (S110), the negative determination is made in step S101 from the next time, and the processing in steps S109 and S110 is executed. To be executed. Therefore, during the one engine operation period, after the failsafe is executed, the failsafe continues regardless of whether the A / D converter 6 is detected to be abnormal.

According to this embodiment described in detail above, the following effects can be obtained. (1) When an abnormality of the A / D converter 6 is detected, the A / D
When the converter 6 is reset and then the opening command value is less than or equal to a predetermined value K, the throttle valve based on the opening command value is provided on condition that no abnormality has occurred in the A / D converter 6. The opening degree control of 3 is permitted. Thus A
When an abnormality occurs in the / D converter 6, the opening control of the throttle valve 3 based on the normal opening command value is continued as much as possible. Therefore, it is possible to suppress the engine output from being suppressed to a necessary minimum and to prevent the traveling performance of the vehicle from being deteriorated in accordance with the execution of the fail safe when the A / D converter 6 has an abnormality.

(2) If the condition that the opening command value is less than or equal to the predetermined value K is not established after the A / D converter 6 is reset, the opening control of the throttle valve 3 is opened normally. What is done based on the degree command value is stopped and the fail safe is executed. Therefore, the fail safe can be appropriately executed when necessary, the opening of the throttle valve 3 can be prevented from being excessively opened from the proper state, and the traveling state of the vehicle becomes inappropriate. Can be suppressed.

(3) Even after the opening command value is equal to or less than the predetermined value K after the A / D converter 6 is reset, the A / D
If the condition that no abnormality has occurred in the converter 6 is not satisfied, the fail-safe is executed, so that the normal opening control of the throttle valve 3 based on the opening command value is continued. There is no. Therefore, the fail-safe can be appropriately executed when necessary, and when the abnormality of the A / D converter 6 is detected after the reset, the normal opening control of the throttle valve 3 is continued, which causes a problem. It can be suppressed.

(4) During the one engine operation period, after the fail-safe is executed, the fail-safe is continued regardless of whether the A / D converter 6 has an abnormality. Therefore, when the fail-safe is executed even once during the engine operation period, the normal opening control of the throttle valve 3 is not executed. Therefore, the throttle valve 3 based on the inappropriate opening command value It is possible to prevent a problem from occurring due to the opening degree control.

The above embodiment can be modified as follows, for example. The predetermined value K used to determine the magnitude of the opening command value may be changed appropriately.

Although the throttle position sensor 8 and the accelerator position sensor 10 have been illustrated as the sensors used for controlling the opening of the throttle valve 3, the present invention can be applied to the case where other sensors are used.

The method for detecting an abnormality in the A / D converter 6 may be changed as appropriate.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a throttle control device in the present embodiment.

FIG. 2 is a flowchart showing a procedure for controlling the opening of a throttle valve when an abnormality occurs in the A / D converter.

[Explanation of symbols]

1 ... Engine, 2 ... Intake passage, 3 ... Throttle valve,
4 ... Motor, 5 ... Electric slot microcomputer, 6 ... A / D converter, 7 ... Control / monitor microcomputer, 8 ... Throttle position sensor, 9 ... Accelerator pedal, 10 ... Accelerator position sensor, 11 ... Driving circuit.

Claims (5)

[Claims] 1. An analog signal from a sensor is converted into a digital signal by an A / D converter, and the opening of a throttle valve is controlled based on an opening command value obtained from the converted signal. In a throttle control device for an internal combustion engine, which performs fail-safe on the throttle valve when an abnormality of the D converter is detected, resets the A / D converter when an abnormality of the A / D converter is detected. And a control means for permitting the opening control of the throttle valve based on the opening command value when at least the condition that the opening command value is equal to or less than the predetermined opening is satisfied. A throttle control device for an internal combustion engine. 2. The control means, after resetting the A / D converter, satisfies the condition that the opening command value is equal to or less than a predetermined opening, and further, the A / D converter The throttle control device for an internal combustion engine according to claim 1, wherein the opening control of the throttle valve based on the opening command value is permitted on condition that no abnormality of the converter is detected. 3. The throttle valve as the fail safe when the condition that the opening command value is equal to or less than the predetermined opening is not satisfied after resetting the A / D converter. The throttle control device for an internal combustion engine according to claim 1 or 2, wherein a change in the opening of the engine is restricted. 4. The control device, even after the condition that the opening command value is not more than a predetermined opening is satisfied after resetting the A / D converter, / D
The throttle control device for an internal combustion engine according to claim 2 or 3, wherein a change in the opening of the throttle valve toward the open side is limited as the fail safe on condition that an abnormality of the converter is detected. 5. The control device continues the fail-safe after execution of the fail-safe, regardless of whether the A / D converter has detected an abnormality. Control device for internal combustion engine.