JPS63198755A - Engine control method - Google Patents

Abstract

PURPOSE:To enable execution of normally optimum control, by a method wherein, when a control signal by means of which running of an engine is computed in a plurality of steps, a part of a plurality of the steps are thinned out in a running region where a change in detection of a running state is slow. CONSTITUTION:During running of an engine, in a control unit 5, a thinning-out decision plug, adapted to decide thinning-out of measurement of an in-stroke suction air amount, is turned over at each crank angle interruption routine. The number of revolutions determined from an output from a crank angle sensor 3 is the decided. When the number of revolutions is below a decision value, a flag decision being thinning-out decision is passed, and in-stroke suction air amount measurement processing is executed. Meanwhile, when exceeding the given value, flag decision by a decision flag is effected, when a flag is 1, in-stroke suction air amount measurement is effected, and when it is 0, the periodic measurement is passed. Namely, when the number of revolutions exceeds a given value, in-stroke suction air amount measure is performed on time each time interruption routine is made two times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for optimally controlling an engine using a microcomputer.

[Conventional technology]

Fig. 2 shows a conventional combustion injection control device for an engine, in which numeral 1 is an air flow sensor that detects the amount of intake air supplied to the engine 2, and numeral 3 is a sensor No. 18 that detects the air flow sensor in synchronization with a predetermined crank angle position of the engine 2. Crank angle sensor that occurs,
4 is a water temperature sensor that detects the cooling water temperature of the engine 2; 5 is a control unit that calculates and outputs the additive injection pulse width No. 3 according to the detection outputs of the air flow sensor 1, the crank angle sensor 3, and the water temperature sensor 4; 6 is a control unit that calculates and outputs the additive injection pulse width No. 3; This is a fuel injection valve that injects fuel in response to a fuel injection pulse signal output from the control unit 5.

Next, the operation of the above configuration will be explained using FIGS. 3 and 4. FIG. 3 shows the main routine, and FIG. 4 shows the crank angle h1j input routine, which is interrupted by a crank angle signal (output of the crank angle sensor 3) generated in synchronization with a predetermined angular position of the engine. First, in FIG. 3, initialization is performed in S301 after key-on, and 530
Engine stalled in 2! ! After performing this, in 3303, an engine stall determination is performed. If the engine stalls, the process returns to 5302, and if not, the process goes to 3304, where various correction coefficients K such as a warm-up correction coefficient correct the warm-up state of the engine based on the detection signal of the water temperature sensor 4. is calculated, and the process returns to 5303.

In the crank angle interrupt routine shown in FIG.
In step 5402, the stroke amount intake air amount Q, which is taken into the engine 2 during the tj period (crack angle Shintan period) is calculated based on the detection signal of the machine Y flow sensor 1, and in step 5402, the stroke amount intake air amount Q, which is taken in by the above calculation is calculated. The basic fuel injection pulse [1] that determines the basic fuel injection amount according to the air iQ, , is calculated by rA. With this basic fuel injection pulse width, τ=Q,,XK6,
K is a constant determined by the pulse width-fuel discharge characteristics. 5403 calculates transient correction images aKA,c for fuel correction due to transient operation of the engine, and calculates the coefficient KAc of B.
0 is determined by the interstroke intake air change Q, -Q, . In 5404, a transient correction calculation is performed to correct the fundamental pulse 1]τ calculated using the transient correction coefficient KAcoJ calculated in 5403 & -8402. The correction pulse 1Jτ is τ=
It is determined by τ×KAcc. In 5405, other correction calculations are performed, and various correction coefficients K are calculated in the main routine. is multiplied by the correction pulse "11r" obtained by the above calculation to obtain the final fuel injection pulse "1" τ.In 8406, the fuel injection pulse width τ obtained as above is used as a fuel injection drive signal to control the fuel injection valve. Output to 6.

Conventionally, as mentioned above, first, various correction coefficients ri! are calculated in the main routine. Next, the stroke amount intake air amount is calculated in the crank angle interrupt routine, and then the fuel injection pulse is obtained by multiplying the basic fuel injection pulse T13 corresponding to the stroke amount intake air amount by the transient correction coefficient and various correction coefficients. 1] By outputting a signal to the fuel injection valve 6 in synchronization with No. 43 of the crank angle sensor 3, the engine is operated at a predetermined air-fuel ratio.

[Problem that the invention seeks to solve]

Incidentally, in recent years, engines have been required to perform various types of transient processing to improve transient characteristics, for example, in order to increase the maximum rotation speed to increase maximum output, or to improve performance through optimal control. , Control is becoming more complex year by year, and processing time is also becoming significantly longer. Therefore, in the past, for example, if the crank angle interrupt routine processing was performed for each crank angle signal at high engine speeds, the fuel injection valve 6 could not be activated at the optimal timing in synchronization with the equal signal of the crank angle sensor 3. However, the processing time of the main routine becomes long, and various correction coefficients are not properly reflected.

This invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an engine control method that can perform optimal control in any driving range.

[Means for solving problems]

The engine control method according to the present invention includes part 1 of a plurality of steps in which control calculations are performed in an operating region where detected changes in operating conditions are slow. The calculation is performed by thinning out the data.

[For production]

In this invention, in the driving region where the detected change is important, some of the multiple calculation steps are thinned out and calculations are performed, so that all the steps are not calculated at each processing timing.
The processing time is shortened, and since the detection change is in the region where the detection change is slow, no inconvenience occurs when pressing down.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a method for controlling a fuel injection control device for an engine will be explained as an example. Its overall configuration and main routine are the same as those in FIGS. 2 and 3. FIG. 1 is a flowchart of a crank angle interrupt routine showing the main dividing method of the embodiment B, in which interrupt processing is performed by a crank angle signal generated in synchronization with a predetermined crank angle position of the engine. First, 3101 is a stroke amount intake air amount measurement (54
02) In the flag reversal step for thinning judgment,
It should be reversed every crank angle interrupt routine. After the flag is not inverted, the rotation speed judgment in 5102 is made, and if the rotation speed is less than a predetermined rotation speed, the flag judgment (3103), which is a thinning judgment for measuring the intake air amount during the stroke, is passed, and the process jumps to the inter-stroke intake air efficiency measurement (3401). . If the rotation speed is above a predetermined number of revolutions, the next step is a flag determination (S103), which is a thinning determination of the stroke amount intake air amount measurement, and if the flag is 1, the next step is the stroke amount intake air amount meter @ (3401). and if O, pass 5401. That is, the stroke amount intake air amount measurement (3401) is performed every crank angle interrupt routine when the number of revolutions is below a predetermined number of revolutions, but is not performed every crank angle interrupt routine when the number of revolutions is above a predetermined number of revolutions. It will be held once in a while.

5401 is an interstroke intake air fish Q that is sucked into the engine cylinder between strokes (between crank angle signals).

This is a step of measuring Q, and, for example, in the detection of the Kalman air flow sensor 1, Q is expressed by the number of pulses between strokes. Note that since the measurement is performed once every two times below the predetermined rotation speed, half of the air amount measured in 3401 is treated as the stroke amount intake air amount Q. Next, in step 3402, a basic fuel injection pulse width τ is calculated which determines the basic fuel injection amount according to the stroke amount intake air amount Qn determined in the above measurement. The pulse width τ is determined by τ=Q,,XK, and K6 is a constant determined by the pulse width-fuel discharge amount characteristic. Note that Q is the previously measured stroke amount intake air amount Q when the stroke amount intake air amount measurement is not performed in the current crank angle interrupt routine at a predetermined rotation speed or higher. use. Next, in 3104, the rotation speed is determined in the same way as in 5102, and if the rotation speed is less than the predetermined rotation speed, the transient correction coefficient is calculated (3
403) and transient correction operation 3g' (3404) are performed, and if the number of revolutions is equal to or higher than a predetermined number of revolutions, 5403 and 5404 are passed and the process jumps to various correction calculation step 5405. Transient correction is performed to compensate for fuel shortage due to transient operation of the engine, and 540
The transient correction coefficient KAcc calculated in step 3 is determined by the changes Q, -Q, in the stroke amount and intake air amount, and the transient correction is performed by multiplying the basic pulse width τ by KAC8.

In 5405, other corrections are calculated, and the correction pulse width τ is multiplied by 0 to the various correction coefficients calculated in the main routine to obtain the final fuel injection pulse width τ. 5406
Then, the fuel injection pulse width τ obtained in step 5405 is outputted to the fuel injection valve 6 as a fuel injection drive signal, and fuel injection is performed at this timing.

As described above, in the flowchart of Fig. 1, in the low rotation range where the change in the stroke amount and intake air amount is large, the stroke amount and intake air amount is measured at each crank angle interrupt timing, and transient correction is performed according to the change in the air amount. However, in the high rotation range where there is almost no change in the stroke volume and intake air volume, the stroke volume and intake air volume measurement is not performed every time at the crank angle interrupt timing, but is thinned out once every two times, and further transient correction based on the air volume is performed. Since it is unnecessary, I try not to do it.

In the above embodiment, the processing in the interrupt routine is thinned out, but it is also possible to thin out some of the various correction coefficient calculation processes in the main routine, and furthermore, in cases where engine control other than fuel injection control is performed at the same time. Of course, it is also possible to omit controls that do not pose a practical problem. Furthermore, the thinning timing is not limited to once every two cycles of the crank angle signal, but may be every multiple cycles or a predetermined time period, or even every predetermined number of times the main routine is processed. Further, although the thinning process is performed at a predetermined rotation speed or higher, depending on the processing content, the thinning process may be performed when the engine load is higher than a predetermined engine load, that is, when the intake airscape during a stroke is higher than a predetermined value.

〔Effect of the invention〕

As described above, according to the present invention, in the driving region where the detected change in the driving state is slow, the processing of the detection output is not performed every time at each processing timing, and unnecessary measurements or corrections are omitted.
This eliminates instability in injection timing due to extended processing time at high engine speeds and delays in reflecting various correction coefficients, making it possible to achieve optimal engine control in any operating range.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of a crank angle interrupt routine in fuel injection control according to the present invention, FIG. 2 is a configuration diagram of a fuel injection control device according to the conventional method and the present invention, and FIG. 3 is a flowchart of the fuel injection control device according to the conventional method and the present invention. FIG. 4 is a flowchart of the crank angle interrupt routine of conventional fuel injection control.
- Crank angle sensor, 4... Water temperature sensor, 5... Control unit, 6... Fuel injection valve.

Claims (4)

[Claims] (1) In microcomputer control that detects the operating state of the engine and calculates a control signal for controlling the engine operation in multiple steps according to the detected output, the multiple steps are performed in an operating region where the detected change in the operating state is slow. An engine control method characterized by thinning out a part of. (2) The engine control method according to claim 1, wherein the operating range is equal to or higher than a predetermined engine speed. (3) The engine control method according to claim 1, wherein the operating range is equal to or higher than a predetermined engine load. (4) The engine control method according to any one of claims 1 to 3, wherein the plurality of steps are interrupt processing.