JPH06249052A - Digital control device of engine - Google Patents

Abstract

PURPOSE:To automatically secure the execution time of other processing than the interruption processing even when the execution time is increased by changing the content of the interruption processing by calculating the control data to control the engine at an optimum timing based on the current data. CONSTITUTION:The number of execution of the interruption processing in synchronization with the engine rotation is counted by a counting means 2 while processing other than the interruption processing is executed by the specified number, and the execution frequency of the interruption processing is determined by an execution frequency determining means 3 according to the result of this count. When the prohibition of the calculation of the control data by a calculating means 1 during the interruption processing is determined by this execution frequency determining means 3, a prohibiting means 4 prohibits the calculation of the control data by the calculating means 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital control device for an engine which controls the fuel injection amount and ignition timing of an engine mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Generally, in a digital controller for an engine of this type, a microcomputer samples input data such as pressure in an intake pipe of an automobile to calculate a valve opening time of a fuel injection valve or a crankshaft rotation. Ignition timing, energization start timing, etc. are calculated based on input data such as moving angle,
The engine is controlled by processing an interrupt routine synchronized with the rotation of the engine based on the calculation result.

FIG. 5 is an explanatory diagram showing the execution frequency of an interrupt process of a general engine digital controller and a process (main process etc.) other than the interrupt process. FIG. 5A shows the engine low speed. Rotation, (B) shows the execution frequency in the engine medium speed rotation, (C) shows the execution frequency in the engine high-speed rotation state, respectively. As the execution frequency of the interrupt increases, the execution time of the other processing decreases and the preset " The "minimum execution time of other processing per unit time" is no longer satisfied {Fig. 5 (C)}.

Therefore, the conventional engine digital control device (hereinafter, referred to as the first conventional device) uses the "minimum execution time of interrupt processing per unit time" and the "minimum execution time of other processing per unit time". The interrupt processing is omitted so as to satisfy both conditions of "," and the skip frequency increases as the activation frequency of the interrupt processing increases.

FIG. 6 is an explanatory diagram showing a case where the frequency of skipping becomes higher as the frequency of activation of interrupt processing becomes higher in the first conventional apparatus. FIG. 6A shows a low engine speed rotation, and FIG. Represents the frequency of omission in the engine medium speed rotation, and (C) represents the omission frequency in the engine high speed rotation state. Is omitted.

As another conventional engine digital control device (hereinafter referred to as the second conventional device), the fuel injection amount and the repetitive fuel injection amount are repeatedly set at a constant time, for example, every 2 to 6 milliseconds in the above-mentioned other processing. A digital controller for an engine that calculates the ignition time and the like has also been proposed. According to the second conventional device, the fuel injection amount, the ignition timing, etc. can be quickly calculated without using interrupt processing.

[0007]

However, in the above-mentioned first conventional apparatus, the execution frequency of the interrupt process is determined by the activation cycle of the interrupt process, and the execution time of the processes other than the interrupt process is actually secured at the specified value or more. If the contents of the interrupt process are changed and the execution time of the interrupt process is increased and the execution time of the other processes is not secured, a step of changing the execution frequency of the interrupt process is not taken into consideration. There was a problem that the numbers etc. had to be reset.

Further, in the second conventional apparatus, there is no problem if the control data is repeatedly calculated every 2 to 6 milliseconds when the engine rotates at high speed, but when the engine rotates at low speed, the control is always performed based on the immediately preceding data. Since the data is not calculated, the calculated data becomes old,
There was a problem that the engine speed fluctuates during idling and the control response is delayed during a sudden call.

The present invention has been made in order to solve the problems of the above-mentioned respective conventional devices, and the control data such as the fuel injection amount and the ignition timing can be calculated at the optimum time without waste based on the latest data. That is, it is possible to automatically secure the execution time of a process other than the interrupt process even if the content of the interrupt process is changed and the execution time is increased without deteriorating the responsiveness of the engine control. It is an object of the present invention to provide a digital controller for an engine capable of performing the above.

[0010]

In order to achieve the above object, the present invention provides a digital engine control device for an engine, which controls a fuel injection amount and an ignition timing of the engine according to control data obtained according to an operating state of the engine. And
While the calculation means for calculating the control data by the interrupt processing synchronized with the rotation of the engine and another processing having a lower priority than the interrupt processing synchronized with the rotation of the engine are executed a predetermined number of times, the calculation means Counting means for counting the number of times the interrupt processing included in the engine rotation is executed, and calculation of control data by the calculating means during the interrupt processing synchronized with the engine rotation based on the counting result of the counting means. A frequency determining means for determining a prohibition frequency, and an output of the frequency determining means, when it is determined that the calculation of the control data by the calculating means during the interrupt processing synchronized with the rotation of the engine this time is prohibited, And a prohibiting unit that prohibits the calculation of the control data by the calculating unit during the interrupt processing synchronized with the rotation. It is an butterfly.

[0011]

According to the present invention, even if the content of the interrupt process is changed and the execution time thereof is increased, the interrupt process synchronized with the rotation of the engine is executed while the processes other than the interrupt process are executed a predetermined number of times. The number of executions of the process is counted, and the interrupt process synchronized with the rotation of the engine is automatically prohibited according to the count result. As a result, it is possible to automatically secure the execution time of the processing other than the interrupt processing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a schematic configuration of a digital control device for an engine according to an embodiment of the present invention,
2 is a flow chart for explaining the operation of the engine digital controller of FIG. 1, FIG. 3 is an execution frequency table of interrupt processing synchronized with the engine rotation of the engine digital controller of FIG. 1, and FIG. FIG. 3 is an operation explanatory diagram of the engine digital controller of FIG. 1.

In FIG. 1, reference numeral 1 denotes a control data calculation means, which interrupts processing in synchronization with the rotation of an engine (not shown) to sample input data such as pressure in the intake pipe and open the fuel injection valve based on the input data. The valve time is calculated, and control data such as ignition timing and energization start timing are calculated based on input data such as the rotation angle of the crankshaft.

Reference numeral 2 is a counting means, and while the main processing, which is processing other than the interrupt processing, is executed a predetermined number of times,
It is a counter C that counts the number of times interrupt processing is executed in synchronization with the rotation of the engine.

3 is an execution frequency determining means (frequency determining means)
Then, the execution frequency of the interrupt process synchronized with the rotation of the engine, that is, the frequency of prohibiting the calculation of the control data by the calculating means 1 during the interrupt process is determined.

A prohibiting means 4 prohibits the calculation of the control data by the calculating means 1 during the interrupt processing synchronized with the current rotation of the engine by the output of the frequency determining means 3.

The operation of the engine digital controller having the above construction will be described below with reference to FIGS. Figure 2
FIG. 2A shows a control procedure of a main process (background process) which is a process other than the interrupt process executed when an interrupt request is not generated, and FIG. 7 shows a control procedure of interrupt processing that is tracked by a signal synchronized with the rotation of the engine such as an output signal (TDC signal).

First, in FIG. 2A, when the main process is executed, the counter C, which is the counting means 2 for counting the number of interrupt processes, is read into the register in step 21, and the next main process is predetermined in step 22. The counter C is cleared in order to count the number of times the interrupt processing is executed during the number of times of execution. Here, an example will be described in which determination is made based on the number of times interrupt processing is executed while main processing is executed once.

Next, in step 23, the read value C 0 of the counter C read in the register in step 21 is read.
Then, the table shown in FIG. 3 is searched and the execution frequency (prohibition frequency) H 0 of the interrupt processing is determined by the execution frequency determining means 3. That is, it is determined in this step 23 how many times the TDC signal interrupt processing is executed in synchronization with the engine rotation. Then, the process proceeds to step 24 to execute other processing, and then returns to step 21.

On the other hand, when the interrupt processing occurs in FIG. 2B, the above-mentioned counter C for counting the number of times the interrupt processing is executed during one cycle of the main processing of FIG. Increment by 1.

Next, at step 26, the counter H for thinning out the calculation of the control data such as the fuel injection amount and the ignition timing by the calculating means 1 is decremented by one. Next, at step 27, it is judged whether or not the counter H is 0,
If it is determined that the value is not 0, the calculation means 1 does not calculate the control data such as the fuel injection amount and the ignition timing.
After proceeding to step 30 and executing other processing, the interruption is restored.

If it is determined in step 27 that the counter H is 0, then in step 28, the counter H is displayed in step 2 of the main process in FIG. 2 (A).
The data of the thinning frequency H 0 searched in 3, that is, the data of how many times the TDC signal executes the interrupt processing in synchronization with the engine rotation is stored. After that, the routine proceeds to step 29, where control means such as the fuel injection amount and the ignition timing are calculated by the calculating means 1, and then the routine proceeds to step 30.

FIG. 4 is a diagram showing the relationship between the execution time of the main process and the execution time of the interrupt process. FIG. 4A shows the number C 0 of times interrupt processing is executed during one round of main processing.
Shows the case of 1. At this time, the retrieved execution frequency H 0 is 1, and the execution frequency is 1/1. The calculation of the data such as the fuel injection amount and the ignition timing by the calculation means 1 is executed for each interrupt process.

FIG. 4B shows the case where the number of times C 0 of executing the interrupt process during one round of the main process is 3.
At this time, the retrieved execution frequency H 0 is 2 and the execution frequency is 1/2. The calculation of the control data such as the fuel injection amount and the ignition timing by the calculating means 1 is executed once every two interrupt processes.

FIG. 4C shows the case where the number of times C 0 of executing the interrupt process during one round of the main process is 7.
At this time, the retrieved execution frequency H 0 is 4, and the execution frequency is 1/4. The calculation of the control data such as the fuel injection amount and the ignition timing by the calculating means 1 is executed once every four interrupt processes.

In this embodiment, the number of times interrupt processing is executed in synchronization with the rotation of the engine is determined every time the main processing completes one cycle. However, the number of main processing is not limited to this. It goes without saying that the same applies to the case where the determination is made for each round.

[0027]

As described above, according to the digital controller for an engine of the present invention, the number of executions of the interrupt processing synchronized with the rotation of the engine is executed while the processing other than the interrupt processing is executed a predetermined number of times. The frequency of calculation of control data such as fuel injection amount and ignition timing is determined based on this counting result, and interrupt processing synchronized with engine rotation is prohibited according to this frequency, so the content of interrupt processing is changed. Even if the execution time increases, the interrupt processing is prohibited if the number of interrupt processing synchronized with the rotation of the engine, which is executed during the predetermined number of times of the other processing, increases.
Therefore, it is possible to automatically secure the execution time of processes other than the interrupt process.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a digital controller for an engine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the engine digital controller of FIG.

FIG. 3 is an execution frequency table of interrupt processing synchronized with engine rotation of the engine digital controller of FIG.

FIG. 4 is an explanatory view of the operation of the engine digital controller of FIG.

FIG. 5 is an operation explanatory diagram of a conventional engine digital controller.

FIG. 6 is an operation explanatory diagram of a conventional engine digital controller.

[Explanation of symbols]

 1 Control Data Calculation Means 2 Counting Means 3 Execution Frequency Determining Means (Frequency Determining Means) 4 Inhibiting Means

Claims (1)

[Claims] 1. A digital control device for an engine, which controls a fuel injection amount and an ignition timing of the engine according to control data obtained according to an operating state of the engine, the interrupt control processing being synchronized with rotation of the engine. An interrupt process in synchronization with the rotation of the engine, which includes the calculation unit, is performed while a calculation unit that calculates control data and another process having a lower priority than the interrupt process in synchronization with the rotation of the engine are executed a predetermined number of times. Counting means for counting the number of times of execution, frequency determining means for determining the frequency of prohibiting the calculation of the control data by the calculating means during the interrupt processing synchronized with the rotation of the engine based on the counting result of the counting means, By the output of the frequency determining means, the control data by the calculating means during the interrupt processing synchronized with the rotation of the engine this time is performed. And a prohibition means for prohibiting calculation of control data by the calculation means during interrupt processing in synchronism with rotation of the engine when it is determined to prohibit calculation of data.