JP2002303201A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device capable of restricting delay of control counters, and favorably executing various types of control based on values of the counters. SOLUTION: An engine ECU 1 is provided with a microcomputer 2. The microcomputer 2 counts values of the control counter respectively used for various types of control at a specified time interval in a base process. Execution timing of various types of control is determined based on the counter values, and an applicable process is executed when the timing is reached. The microcomputer 2 counts up a reference counter in a constant time interrupting process, and determines delay of the base process by referring to the reference counter at every timing counted up by the control counter. When this delay is as large as counting action width for one time by the control counter, the value of the control counter is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for appropriately controlling the counting operation of a control counter used in various controls in a vehicle control device used for controlling a vehicle-mounted engine, for example.

[0002]

2. Description of the Related Art In a vehicle control apparatus of this type, various kinds of control are performed by a microcomputer (microcomputer) at intervals of time. At that time, in a base process, a control counter is counted up (counted) at a predetermined time cycle. Is done. The execution timing of various controls is determined based on the value of the control counter. For example, in the base routine of FIG. 7, the microcomputer determines whether or not 4 ms specified in step 300 has elapsed. And 4m
When s has elapsed, in step 310, the control counter cnt4ms is counted up. Thereafter, the process proceeds to step 320 to perform a predetermined process, and then returns to step 300 again.

[0003]

By the way, in an electronic control unit (ECU) used for control of a vehicle-mounted engine, etc.,
When the processing load of the microcomputer increases during a transient operation of the vehicle, at a high engine speed, or the like, the interruption of the time synchronization or the angle synchronization increases accordingly, and the processing is delayed in the base routine having a lower priority. As a result, the count-up of the control counter is delayed, and the update timing of the RAM or the flag that uses the counter value as an update condition is delayed. That is, a delay occurs in the control operation by the ECU.

As a countermeasure to prevent delay of the control counter, it has been conventionally proposed that the count-up process of the control counter is all shifted to a high-priority periodic interrupt, and the count-up of the control counter is performed with priority. Have been. However, in this configuration, although the count-up of the control counter can be performed at the theoretical timing, a large number of control counters are required in the engine ECU and the like, so that the processing load due to the periodic interruption is excessively increased. In other words, the time increase due to the count-up process due to the periodic interrupt becomes large, and adverse effects such as delay of other interrupts occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to suppress the delay of a control counter, and to appropriately execute various controls based on the value of the counter. It is an object of the present invention to provide a vehicle control device that can perform the control.

[0006]

According to the first aspect of the present invention, the value of the control counter used individually in each control is counted by the microcomputer at predetermined time intervals in the base processing. Then, various control timings are determined based on the counter value, and when the timing is reached, the corresponding vehicle control is executed. Also,
The microcomputer includes a reference counter counting unit, a delay calculating unit, and a delay correcting unit. The reference counter counting means counts the value of the reference counter in the periodic interrupt processing having a higher priority than the base processing, and the delay calculating means refers to the value of the reference counter at each timing of counting the control counter. To calculate the delay of the base processing. Then, if the delay of the base processing has reached the width of one count operation by the control counter, the delay correction means corrects the value of the control counter. In this way, the base processing is delayed due to an increase in the processing load on the microcomputer, and even if the control counter value is delayed due to the delay, the control counter is determined based on the reference counter value that causes almost no delay. Is corrected to the normal value. In addition, by correcting the control counter when the delay of the base processing reaches one count operation width by the control counter, correction according to the minimum unit of the control counter can be performed, and quick correction can be performed if necessary. The counter value can be corrected. As a result, various controls based on the value of the control counter are performed in accordance with the theoretical timing, and it is possible to prevent an adverse effect on the vehicle control when the processing load of the microcomputer increases.

According to the second aspect of the present invention, the delay of the base processing is integrated each time, and the integrated delay value is obtained. Then, if the delay integrated value has reached the count operation width for one time of the control counter, the value of the control counter is corrected. In this case, the delay correction of the counter value can be properly performed by obtaining the cumulative delay of the base processing and performing the correction based on the cumulative delay.

According to the third aspect of the invention, the degree of delay is calculated based on the ratio of the control counter to the time interval of the counting operation, and the degree of delay is integrated. Then, if the integrated value of the degree of delay is “1” or more, the value of the control counter is corrected using the integer part of the integrated value. Here, by calculating the degree of delay as a ratio to the time interval of the counting operation of the control counter, "1" of the degree of delay corresponds to "1" of the counter value of the control counter. That is, the degree of delay of the base processing is obtained in accordance with the minimum unit of the control counter. Then, when the integrated value of the degree of delay becomes “1” or more, by correcting the value of the control counter using the integer part of the integrated value, the arithmetic processing by the microcomputer can be simplified, The memory capacity required for the arithmetic processing can be reduced.

According to the fourth aspect of the present invention, the integrated value is subtracted by an amount corresponding to the correction of the value of the control counter. In this case, if there is a delay in the base processing in the integrated value, the value is carried over to the next time and thereafter, and the delay correction of the counter value can be continuously performed.

Further, if the time interval of the counting operation of the control counter is set to an integral multiple of the reference counter, the delay of the base processing is accurately calculated, which is practically preferable.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an engine ECU 1 for controlling the operation state of the engine. The engine ECU 1 includes a microcomputer (microcomputer) 2 that performs various controls.

The microcomputer 2 takes in sensor detection signals such as a crank signal output from a crank angle sensor (not shown), an intake pressure signal output from an intake pipe pressure sensor, and an engine water temperature signal output from a water temperature sensor. And
The microcomputer 2 outputs a control signal to the injector, the igniter, and the negative pressure control valve (VSV) based on these signals. That is, the microcomputer 2 performs the fuel injection control,
Various controls such as ignition timing control and purge control are performed.

More specifically, the microcomputer 2 counts up a plurality of control counters individually used in various controls in a base routine, and further determines execution timings of various controls based on the counter values. , The corresponding process is performed. Here, as the control for adjusting the execution timing by the control counter, in the present embodiment, purge control will be described as an example. It should be noted that the purge control is a control for discharging the evaporated fuel (evaporative gas) generated in the fuel tank to the engine intake system as is well known, and the microcomputer 2 controls the negative pressure control valve (VS
By opening and closing V), the amount of gas (purge gas amount) guided to the engine intake system is adjusted.

FIG. 2 is a flowchart showing a control procedure of the purge control. The process of FIG. 2 is performed for a predetermined time (for example, 4 m).
This is executed by the microcomputer 2 every s). In FIG.
First, in step 100, the microcomputer 2 determines whether or not the purge execution condition is satisfied. The purge execution condition is based on the engine operating state, and is established, for example, when the engine speed is equal to or higher than a predetermined speed and the intake air amount is equal to or higher than a predetermined amount. If this condition is not satisfied, the microcomputer 2 proceeds to step 110, sets the value of the control counter cnt4ms to “0”, turns off the negative pressure control valve (VSV) in step 120, and executes this processing. To end. On the other hand, when the execution condition of the purge is satisfied, the microcomputer 2 proceeds to step 130 and determines whether or not 5 seconds or more based on the value of the control counter cnt4ms. This control counter cnt
The value of 4 ms is counted up every 4 ms in the base routine. Therefore, when the value of the control counter cnt4ms is less than 1250, the microcomputer 2 makes a negative determination in step 130, and in step 120, the negative pressure control valve (VSV)
Is turned off, and the present process ends. On the other hand, the control counter c
When the value of nt4ms becomes 1250 or more (five seconds after the purge execution condition is satisfied), the microcomputer 2 proceeds to step 140, turns on the negative pressure control valve (VSV), and ends this processing.

By the way, the control counter cnt4ms
Are counted up at a period of 4 ms in the base routine of the microcomputer 2. When the control timing is determined based on this counter value, when the processing load of the microcomputer 2 is small, the control counter cnt4ms counts up as theoretically as shown by the solid line in FIG. 3, and the purge control is delayed. It is implemented without. That is,
The negative pressure control valve (VSV) is turned on at the timing of t2 after the elapse of 5 seconds from the timing of the timing t1 when the purge condition is satisfied. However, when the processing load on the microcomputer 2 increases, the priority of the base routine is originally low.
As shown by the broken line, the count of the control counter cnt4ms is delayed, and the ON timing (timing of t3) of the negative pressure control valve (VSV) is delayed.

Therefore, in the present embodiment, it is considered that the delay of the control counter cnt4 ms is suppressed to prevent the delay of the control timing. Specifically, a reference counter cnt for detecting a delay in the base processing is newly prepared. And a microcomputer 2 as a reference counter counting means.
Increments the value of the reference counter cnt in step 200 of FIG. The process in FIG. 4 is a high-priority periodic interrupt process that occurs in a 1 ms cycle. With this process, as shown in FIG. 5A, the reference counter cnt has almost no delay every 1 ms. Functions as a free-run counter that counts up.

Here, when the processing load on the microcomputer 2 is small and the base processing is not delayed, as shown in FIG. 5B, the value of the control counter cnt4ms is counted up every 4 ms. On the other hand, if the processing load on the microcomputer 2 is large and the base processing is delayed, for example, FIG.
As shown in (c), the count-up interval in the period t10 to t20 is 6 ms. That is, although the counting up of the control counter cnt4ms is delayed, in the present embodiment, the delay of the base processing is calculated by referring to the value of the reference counter cnt, and the control counter cnt4ms is calculated based on the delay. The value is corrected.

Hereinafter, a method of correcting the control counter cnt4ms in this embodiment will be described. First, the value of the reference counter cnt is referred to at each count-up timing of the control counter cnt4ms, and the delay is calculated as in the following equation.

Delay (i) = (cnt (i) -cn
t (i-1) -4ms) / 4ms where the subscripts i and i-1 indicate the current value and the previous value, respectively. In this equation, the time interval of the base processing is obtained by subtracting the previous value from the current value of the reference counter cnt. Furthermore, the time interval when there is no delay (reference value)
By subtracting 4 ms, a delay in time unit is calculated, and the delay in time unit is 4 ms of the reference value.
And delay is obtained. That is,
The delay “delay” is obtained as a ratio (degree of delay) to the time interval (4 ms) of the count operation of the control counter cnt4 ms.

Here, if the base processing is executed according to the theoretical timing, cnt (i) -cnt (i-1)
Is 4 ms, and the delay “delay” is always “0”. However, if a delay occurs in the base processing, c
nt (i) −cnt (i−1)> 4 ms, and the delay d
elay is a value corresponding to the delay of the base processing. For example, at the timings t15 and t20 in FIG. 5C, the processing interval is 6 ms behind the normal 4 ms, so that delay (i) = (6 ms−4 ms) / 4 ms = 0.
5

Further, as shown in the following equation, the delay integrated value del
aysum is calculated. delaysum (i) = delaysum (i-1)
+ Delay (i) By this equation, the delay is integrated, and FIG.
As shown in the timing chart of FIG.
m = 0.5, and at the timing of t20, delay
sum = 1.0.

Then, as shown in the following equation, delaysum
Delay correction value delayadj using only the integer part of
Is required. delayaj = INT (delaysum (i)) Then, as shown in the following equation, the delay correction value delayad is different from the normal count operation of the control counter cnt4ms.
By adding j, the delay of the counter value is corrected.

Cnt4ms (i) = cnt4ms (i−
1) + 1 + delayadj Specifically, as shown in (c) and (d) of FIG.
At the timing of 0, the delay integrated value delaysum
Since (i) = 1.0, the control counter cnt4m
The value of s is corrected to the normal value of "14" by adding "1" of the count-up and "1" of the delay correction value delayadj to the previous value of "12".

After the correction of the counter value, the delay correction value delayadj is subtracted from the delay integrated value delaysum (i) as in the following equation. delaysum (i) = delaysum (i) -d
elayadj That is, in the present embodiment, the control counter cnt4m
Processing delays are calculated and integrated at each count timing of s, and when the delay integrated value delaysum becomes equal to or greater than "1", the counter value is corrected.

Next, the delay correction process in the base routine executed by the microcomputer 2 will be described with reference to the flowchart of FIG. In FIG. 6, first, in step 210, the microcomputer 2 determines whether 4 ms has elapsed,
If 4 ms has not elapsed, steps 220 to 260
This processing is terminated without executing. On the other hand, if 4 ms has elapsed, the microcomputer 2 proceeds to step 220, refers to the value of the reference counter cnt, and stores the value in the built-in memory of the microcomputer 2. The value stored in the memory is used as the previous value of the reference counter cnt in the next process.

Then, the microcomputer 2 calculates the delay "delay" of the base processing in step 230, and calculates the delay integrated value "delaysum" in step 240. Further, in step 250, the microcomputer 2 performs the count-up of the control counter cnt4ms and performs the delay correction by adding an integer part (the delay correction value delayadj) of the delay integrated value delaysum. Thereafter, in step 260, the microcomputer 2
Is the delay correction value del from the delay integration value delaysum
ayadj is subtracted.

In this embodiment, the processing of steps 230 and 240 in FIG. 6 corresponds to the delay calculating means, and the processing of step 250 corresponds to the delay correcting means. In the above description, the control counter cnt used for the purge control is used.
Although 4 ms has been described as an example, all control counters used for injection control, ignition timing control, and the like similarly correct the delay of the counter value with reference to the value of the reference counter cnt. Specifically, for example, in the case of the control counter cnt8ms that counts up at a time interval of 8ms, the delay “delay (i) = (cnt (i) −cnt (i−1)”)
−8 ms) / 8 ms, and the integrated value “dela” of the delay “delay”
When ysum becomes “1” or more, the control counter c
Correction of nt 8 ms is performed.

According to the embodiment described in detail above, the following effects can be obtained. (1) Even if the base processing is delayed due to an increase in the processing load of the microcomputer 2 and the value of the control counter cnt4ms is accordingly delayed, the control counter based on the value of the reference counter cnt which hardly causes a delay. cnt4ms
Is corrected to the normal value. When the delay of the base processing reaches one count operation width (counter value “1”) by the control counter cnt4 ms, the control counter c
By performing nt4 ms correction, the control counter c
Correction according to the minimum unit of nt 4 ms becomes possible, and the counter value can be quickly corrected as needed.
As a result, the purge control based on the value of the control counter cnt4ms is performed according to the theoretical timing, and the microcomputer 2
Can be prevented from adversely affecting the vehicle control when the processing load increases. In addition, in the case of the high-priority periodic interrupt processing, since only one reference counter cnt is added, the problem that the interrupt load does not excessively increase and other interrupt processing is delayed is avoided. it can.

(2) At each count timing of the control counter cnt4ms, the delay "delay" of the base processing is integrated to obtain a delay integrated value "delaysum", and the counter value is corrected based on the delay integrated value "delaysum". In this case, the delay correction of the counter value can be properly performed by obtaining the cumulative delay of the base processing and performing the correction based on the cumulative delay.

(3) The delay “delay” is calculated as a ratio (delay degree) to the time interval (4 ms) of the count operation of the control counter cnt 4 ms, and the delay “delay” is calculated.
When the integrated value delaysum of is equal to or more than “1”,
The value of the control counter cnt4ms is corrected using the integer part of the integrated value delaysum. Here, by calculating the delay “delay” as a ratio to the time interval (4 ms) of the count operation of the control counter cnt4ms, “1” of the delay “delay” corresponds to “1” of the counter value in the control counter cnt4ms. . That is, the delay “delay” is equal to the control counter cnt4.
It is determined according to the minimum unit of ms. Then, when the integrated value delaysum is equal to or more than “1”, the arithmetic processing of the microcomputer 2 can be simplified by correcting the value of the control counter cnt4ms using the integer part of the integrated value delaysum, The memory capacity required for the arithmetic processing can be reduced.

(4) When the value of the control counter cnt4ms is corrected, the delay integrated value delaysu is corrected by the correction.
m (i) was subtracted. In this case, if a delay of the base processing remains in the delay integrated value delaysum,
The value is carried over from the next time, and the delay correction of the counter value can be continuously performed.

(5) Since the time interval of the count operation of the control counter cnt4ms is an integral multiple (four times) of the reference counter cnt, the delay is accurately calculated, which is practically preferable.

The present invention can be embodied in the following forms other than the above. In the above-described embodiment, the delay (delay) including the time ratio is obtained as the “delay of the base process”, but the present invention is not limited to this. For example, the delay time is determined as “delay in base processing”. In this case, if the control counter counts up at a time interval of 4 ms, the delay time is calculated as delay time = cnt (i) −cnt (i−1) −4 ms. Then, when the delay time is equal to or longer than the time interval (4 ms) which is the counting operation width of the control counter, the counter value is corrected.

In the above embodiment, the time interval of the count operation of the control counter cnt 4 ms is four times as long as the reference counter cnt. Therefore, the delay is integrated. If the counter counts at the same time interval, the delay d
There is no need to integrate elay.

Further, the reference counter cnt and the control counter cnt4ms are up-counters that perform a count-up operation. However, the present invention is not limited to this, and the present invention may be embodied as a down-counter.

In the above-described embodiment, the present invention is embodied in the engine ECU 1 for controlling the vehicle-mounted engine.
The present invention may be embodied in an ECU that performs other control such as transmission control.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of an ECU according to an embodiment of the invention.

FIG. 2 is a flowchart showing a control procedure of purge control.

FIG. 3 is a time chart showing an outline of purge control.

FIG. 4 is a flowchart showing a count process of a reference counter.

FIG. 5 is a time chart for explaining a delay correction process.

FIG. 6 is a flowchart illustrating a delay correction process.

FIG. 7 is a flowchart showing a base routine in the related art.

[Explanation of symbols]

Reference numeral 1 denotes an engine ECU as a vehicle control device, 2 denotes a microcomputer, cnt denotes a reference counter, and cnt4 ms denotes a control counter.

Claims (5)

[Claims] 1. A microcomputer for executing various controls of a vehicle, wherein the microcomputer counts values of control counters used individually in each control at predetermined time intervals in a base process, and further includes a microcomputer. A vehicle control device that determines various control timings based on a counter value, and executes a corresponding control when the timing is reached, wherein the microcomputer is configured to execute a higher priority interrupt processing than the base processing. Reference counter counting means for counting the value of the reference counter, delay calculation means for calculating the delay of the base processing by referring to the value of the reference counter for each timing of counting the control counter, and the delay calculation means When calculating the base processing delay, the base processing delay is added to the control counter. Batch of if reached counting width that, the vehicle control device, characterized in that it comprises a delay correcting means for correcting the value of the control counter. 2. The vehicle control device according to claim 1, wherein the delay calculating means obtains a delay integrated value by integrating a delay of the base processing each time, and the delay correcting means determines that the delayed integrated value is A vehicle control device that corrects the value of the control counter when the count operation width of the control counter reaches one count. 3. The vehicle control device according to claim 1, wherein the delay calculating means calculates a delay degree based on a ratio of the control counter to a time interval of a counting operation, and integrates the delay degree. The vehicle control device, wherein the delay correction means corrects the value of the control counter using an integer part of the integrated value when the integrated value of the delay degree is “1” or more. 4. The vehicle control device according to claim 2, wherein when the value of the control counter is corrected, the integrated value is subtracted by the correction. 5. The vehicle control device according to claim 1, wherein a time interval of the counting operation of the control counter is an integral multiple of the reference counter.