JPS59173530A - Fuel injection timing control device for internal- combustion engine - Google Patents

Abstract

PURPOSE:To make fuel injection response uniform at transition in each cylinder, by changing a phase of fuel injection timing every start of engine rotation and thereby making uniform a time when fuel stays in an intake manifold. CONSTITUTION:Fuel injection timing is computed by a control circuit 10 on the basis of a rotational speed data by a rotational angle sensor 6 and a suction air amount data by an air flow meter 3 to control a fuel injection valve 7. The control circuit 10 is provided with a setting means for setting a plurality of injection start signal generation conditions according to the number of cylinder. The control circuit 10 is further provided with a decision means for deciding whether or not an engine rotational speed is zero, a selecting means for selecting one of the injection start signal generation conditions upon start of engine rotation, and a timer means for cumulatively calculating a time from end of fuel cut to the next fuel cut for the signal generation condition as selected. The selecting means serves to select an injection start signal generation condition where a cumulative time calculated in the timer means is minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a fuel injection timing control system for an internal combustion engine that performs simultaneous injection in all cylinders. The fuel injection amount is calculated according to the amount (or intake pipe pressure) and the rotational speed, and this is synchronized with the rotational speed to inject all cylinders simultaneously. Normally, in a 4-cycle engine, this four-stage ringing occurs once every revolution of the crank. Therefore, in this case, 1/2' of the above-mentioned fuel injection amount is simultaneously injected into the trough cylinder every 360 degrees of crank angle.

Prior Art and Problems The phase of the conventional four-stage blower is fixed for each cylinder. Therefore, for example, in a 6-cylinder engine, injection for the 1st and 6th cylinders is performed in the compression and exhaust strokes, injection for the 2nd and 5th cylinders is performed in the compression and exhaust strokes, and injection for the 3rd and 5th cylinders is performed in the compression and exhaust strokes. Four-cylinder injection is performed during the intake and explosion strokes.

Therefore, the amount of time that the injected fuel stays in the air manifold on the back side of the intake pipe before being actually sucked into the combustion chamber differs from cylinder to cylinder. The amount of impurities contained in the fuel or the amount of deposit knots such as carbon or the like on the MR lid and carbon deposit differs depending on the amount. As a result, there is a problem in that the fuel response during transient times differs for each cylinder.

Purpose of the Invention The present invention is based on the above-mentioned problems in the conventional form.
By changing the phase of fuel injection timing each time the engine starts rotating, the time that fuel stays in the intake manifold becomes uniform in each cylinder, thereby reducing the build-up of impurities on the back side of the intake pipe and the intake manifold port. The purpose of this invention is to make the amount of carbon or deposits and the amount of deposits such as carbon adhered to each cylinder uniform, thereby making the fuel response during transient times uniform among the cylinders.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention for achieving the above-mentioned objects is shown in FIG. That is, the injection start signal generation state setting means sets a plurality of injection start signal generation states according to the number of cylinders of the internal combustion engine, and the engine rotation speed determination means determines whether the engine rotation speed is O or not. The injection start signal generation state selection means selects one injection start signal generation state when the engine starts rotating. As a result, the time from the fuel cut return to the next fuel cut (1) is cumulatively measured by the timer means for the selected injection start signal generation state. The injection start signal No. 6 generation state selection means selects the injection start signal generation state in which the cumulative time measured by the timer means is the minimum.

Examples of the invention Embodiments of the present invention will be explained below with reference to the drawings.

FIG. 2(4) to FIG. 2(C) are diagrams for explaining the principle 1r of the present invention: an injection start signal generation state for explaining. For example, in a 6-cylinder engine, ignition is controlled in the order of 1st cylinder → 5th cylinder → 3rd cylinder → 6th cylinder → 2nd cylinder → 4th cylinder, but fuel injection is performed in all cylinders simultaneously and every 360° CA. . 1 cylinder, 1 cylinder and 6 cylinders, 5 cylinders and 2 cylinders,
Three cylinders and four cylinders form three groups. Therefore, in the present invention, in the case of a six-cylinder engine, as shown in FIG.
Three states are set: the injection start signal generation state shown in FIG. 2(CB), and the injection start signal generation state shown in FIG. 2(C).

In FIG. 2(A), injection starts at 60° OA before top dead center as indicated by arrows X1 and X2 for cylinders 1 and 6. Figure 2 (B) The smell is 3 cylinders and 4 cylinders.
60° before top dead center as shown by arrows X3 and X4 with respect to the cylinder
Injection starts at CA. In Figure 2 (C), 5
Injection starts at 60° CA before top dead center as shown by arrows X5 and X6 for cylinders and two cylinders. In these three states, the injection start timing is shifted by 120°CA7.The present invention changes these three states every time the engine starts rotating, so that fuel stays in the intake manifold. Between f'? f: It is made to be uniform in each cylinder.

Note that Sl and S2 are a circular rotation angle sensor for determining cylinders (5 in Fig. 3) and an N rotation angle sensor for forming rotation speed (5), respectively.
Each output signal of 6) in FIG. 3 is shown.

FIG. 3 is an overall schematic diagram showing an embodiment of a fuel injection timing control device for an internal combustion engine according to the present invention. In Figure 3,
An air flow meter 3 is provided in the intake passage 2 of the aircraft chest body 1. The air flow meter 3 directly measures the amount of intake air, has a built-in potentiometer, and generates an analog voltage electrical signal proportional to the amount of intake air.

The IJ computer 4 is provided with two rotation angle sensors 5 and 6 that generate angular position signals every time the shaft rotates by 720 degrees or 30 degrees in terms of a crankshaft. The angular position signals of the rotation angle sensors 5 and 6 act as an interrupt request signal for fuel injection timing, a reference timing signal for ignition timing, an interrupt request signal for fuel injection amount calculation control, an interrupt request signal for ignition timing calculation side, etc. do.

Further, the intake passage 2 is provided with a fuel injection valve 7 for supplying pressurized fuel from a fuel supply system to the intake port for each cylinder.

The control circuit 10 includes an air flow meter 3, a rotation angle sensor 5,
It processes signals such as 6 and performs fuel injection calculations, etc., and is configured as a microcomputer.

4 is a detailed block circuit diagram of the control circuit 10 shown in FIG. 3. In FIG.
/D transformer 102. That is, A/D
The i converter 102 is a multiplexer selectively controlled by the CPU I O6. 101t - air 70 fed through
- The clock generation circuit 10 converts the analog output signal of the meter 3 into
A/D conversion is performed using the clock signal CLK of
After the /D conversion is completed, an interrupt signal is sent to the CPU 106. As a result, in the interrupt routine, the latest data of the air flow meter 3 is taken in and stored in a predetermined area of R (108).

Each of the rotation angle sensors 5 and 6 is supplied to a timing generation circuit 103 for generating an interrupt request signal and a reference timing signal. The timing generation circuit 103 has a timing counter, which is incremented by the pulse signal of the rotation angle sensor +j6 every 30° CA and reset by the pulse signal of the rotation angle sensor 5 every 720° CA. . Roughly speaking, the pulse signal of the rotation angle sensor 6 is supplied to a predetermined position of the input interface 105 via the rotation speed forming circuit 104 .

The rotational speed forming circuit 104 consists of a gate that is controlled to open and close every 30 degrees CA, and a counter that counts the number of pulses of the clock No. 01 CLK of the clock generation circuit 107, which passes through the gate of Omahito, to one. , thus a binary signal is formed that is inversely proportional to the rotational speed of the engine.

The ROM 109 stores in advance programs such as a main routine, a fuel injection amount calculation opening routine, and an ignition timing calculation control suppression routine, as well as fixed data and constants necessary for these processes.

CPU I O6 is the fuel injection amount data (hour 1nJ) calculated in the fuel injection amount calculation control interrupt routine.
The drive circuit 111 via the output interface 110
Send to. The drive circuit 111 has a register that receives the above-mentioned fuel injection time, a counter that counts the clock signal CLKi of the clock generation circuit 107 after receiving the fuel injection start signal, and a comparator that compares the value of the register with the value of the counter. The comparator continues to send the injection nozzle signal to the fuel injection valve 7 after the fuel injection start signal is supplied until the above two values match. As a result, the fuel injection valve 7 is energized for the above-mentioned fuel injection time, so that an amount of fuel corresponding to the fuel injection time is sent into the combustion chamber of the engine body 1.

FIG. 5 is a flowchart for explaining the operation of the control circuit 10 of FIG. 4, and shows a part of the main routine.

In FIG. 5, A-0 indicates the injection start signal generation state shown in FIG. 2(A), A=1 indicates the injection start signal generation state shown in FIG. The injection start signal generation state shown in FIG. 2(C) is shown.

First, the Stella f501 takes in the rotational speed data Ne from the rotational speed forming circuit 104, and determines whether N8=0 or not. If Ne\0, proceed to step 503; on the other hand,
If Ne-0, the process proceeds to step 504.

In step 503, flag F is set to 0. The value Nt is a timer counter value that measures the time from the start of rotation to the stop of the engine, and is counted up every 4 m (8) using another routine. This timer counter value is Nt x 4 m when converted to time.

Next, when the rotation of the engine stops, the flow of step 501 first proceeds to step 504 (at this time, F=
Since the answer is O, the processes of steps 505 to 521 are executed.

In steps 505 and 506, it is determined whether A is 0.1 or 2. In other words, the state in which the injection start signal is generated before the rotation of the engine stops is shown in FIG. 2(A).

It is determined whether it is shown in FIG. 2(B) or FIG. 2(C). If A=O, proceed to Stella f507 and get the A=O abuse timer counter value N. Accumulatively add Nj to , and if A=1, proceed to Stella 7"508 and A=1
Status timer counter value N! Cumulatively add Nj to A
If =2, the process proceeds to step 509, where Nt is cumulatively added to the timer counter value N2 for the A-2 state.

In step ``51'' (1,511,542, when the next rotation of the engine is restored, A=O state, A=1 state, or if
:To select A=2 state, timer counter value N
. p Nl p Detect the minimum value sound of N2.

If the value No is the minimum, proceed to step 513 and set the A=O state; if the value N1 is the minimum, proceed to step 514 and set the A=1 state; if the value N2 is the minimum, step 51
Proceed to step 5 to set A=2 state.

In steps 516 to 521, the timer counter value No.
, Nl, and N2 will be re-standardized.

Finally, the minimum timer counter value/kotoe is set as the minimum timer counter value tO after subtracting NO from another timer counter value, for example, Nl p N2.

In step 522, a flag F'(i-1) is set to prevent steps 505 to 521 from being executed again while the rotation of the gate is stopped.

In other words, the flow of step 504 proceeds to step 523.

In step 523, the timer counter value Nt is cleared.

FIG. 6 is also a flowchart for explaining the operation of the control circuit 10 of FIG. 4, and shows a fuel □□□ arrival execution routine. This routine is performed at 30 of the rotation angle sensor 6.
This is an interrupt routine executed by the ie routine (No. 8) for each °CA.

Interrupt Stella f601 to Nutatoshi, Stetsu f602
, 603. In steps 602 and 603, it is determined whether A is 0, 1 or Vi, 2.

If A=0, proceed to snap 604; if A=1, proceed to Stella f606; if A-2, proceed to step 608
Proceed to.

In steps 604 to 609, the timing generation circuit 10
The value N of the timing counter within 3 is determined. That is, in this case, N = 11.23 is X 1 in Figure 2 (5)
? N=7,19 corresponds to x, N4 in Figure 2(B), N=2,15 corresponds to X in Figure 2(C)
Compatible with 5+X6. Only when the determination is positive in any of Stella f604 to f609, the process proceeds to step 610, where the CPU 106 sends an injection start signal to the drive circuit 111 via the output interface 110.

This routine then ends at step 611.

When the injection start signal is supplied to the drive circuit 111 by the interrupt routine shown in FIG. Drive circuit 111
will energize the fuel injection valve 7.

In the above embodiment, three injection signal generation states are set for a six-cylinder engine, but other numbers of states can also be set. ``Also, the same applies to a 4-cylinder or 8-cylinder engine.Furthermore, the timer counter value No, N! which is the content of the RAM 108.

N2 and status value A are preferably transferred to a backup memory and used again for the next process when the microcomputer power is turned off.

The conventional fuel injection method is shown in Figure 2 (A) and Figure 2 (B).
) or Figure 2 (rc only in one state of C or l)
I was dependent on it.

As described in detail, according to the present invention, the phase of the fuel injection timing is changed every time the engine starts rotating, so that the fuel response during transient times can be made uniform among the cylinders.

[Brief explanation of drawings]

FIG. 1 is an overall block diagram for explaining the present invention in detail, FIGS. 2 (4) to (C) are diagrams for explaining the generation state of a companion injection start signal for explaining the present invention in detail, FIG. 3 is an overall schematic diagram showing an embodiment of the fuel injection timing control device for an internal combustion engine according to the present invention, FIG. 4 is a detailed block circuit diagram of the control circuit shown in FIG. 3, and FIGS. 4 is a flowchart for explaining the operation of the control circuit IO of FIG. 4. FIG. l... Engine body, 3... Air flow meter, 5, 6
...Rotation angle sensor, 7...Fuel injection valve, 10...
control circuit. Figure 1

Claims (1)

[Claims] 1. In an internal combustion engine that performs simultaneous injection in all cylinders, injection start signal generation state setting means for setting a plurality of injection start signal generation states according to the number of cylinders, and determining whether the rotational speed of the MJHt engine is 0 or not. an engine rotational speed determination means for selecting one of the injection start signal generation states when the engine starts rotating; A timer means for cumulatively measuring the time from the return of fuel cut to the next fuel cut; A fuel injection timing control device for an internal combustion engine, characterized in that the fuel injection timing control device selects the following.