JPH05332177A - Starting time fuel injection control device of multiple cylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To enable a cylinder for injecting fuel from the beginning at the time of start to be discriminated, and enable sequential injection. CONSTITUTION:A cylinder for injecting fuel is judged by the value of a cylinder judging counter for counting a REF signal on the basis of the cylinder judging signal in a referential crank angle signal (REF signal) from a crank angle sensor 1 so as to drive a fuel injection valve 3 provided on per cylinder. When an ignition switch 5 is turned off to stop an engine, the value of a then counter is memorized in a memory 9, and then, a main power supply is broken to a CPU 4. When a start switch 6 is turned on to start the engine, contents stored in the memory 9 are read out, and discrimination of cylinders is started, on the basis of the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control for a so-called sequential injection type multi-cylinder internal combustion engine in which a fuel injection valve is provided for each cylinder in an intake system, and fuel injection is performed in synchronism with the stroke of each cylinder. The present invention relates to a device, and more particularly to a fuel injection control device at the time of starting.

[0002]

2. Description of the Related Art Conventionally, in a sequential injection type fuel injection control device, as shown in FIG. 6, a reference crank angle signal (REF signal) and a unit crank angle signal (ANGLE signal) from a crank angle sensor 1 are input. The engine control unit (ECU) 2 controls the operation of the plurality of fuel injection valves (injectors) 3 separately.

Here, the REF signal is output for several cylinders (six cylinders for six cylinders) per two revolutions of the crankshaft, one of which is output.
One is different in pulse width for cylinder discrimination and can be discriminated. Therefore, as shown in FIGS. 7 and 8, fuel injection is performed in synchronization with the REF signal, but the value of the cylinder discrimination counter in FIG. 7 is incremented by the interruption by the REF signal, and the cylinder discrimination signal in the REF signal is incremented. Is detected (and the value of the counter reaches 6), the cylinder is reset based on the value of the counter, and fuel injection is performed.

As a result, fuel injection is performed before the intake stroke of each cylinder, that is, during the exhaust stroke. However, at the time of start-up, it is not known which cylinder the fuel should be injected to until the first cylinder discrimination signal is input. Therefore, fuel is injected simultaneously to all the cylinders (Japanese Patent Laid-Open No. 58-9133).
No. 8).

That is, as shown in FIG. 9, until the cylinder can be discriminated at the time of starting, for example, when the counter values are 1 and 4, 1 / of the amount required for one combustion for all cylinders. Two fuels are being injected simultaneously.

[0006]

However, in such a conventional fuel injection control device at the time of starting, as shown in FIG.
In the case of the above example, since the # 5 cylinder has only half the required amount of fuel in the first intake stroke, it becomes a lean air-fuel mixture, and eventually it does not burn and raw gas is released. Two
In the # 4 cylinder, there was 1.5 times the required amount of fuel during the first intake stroke, resulting in a rich mixture, and without combustion,
There was a problem that raw gas was released.

Further, in Japanese Patent Laid-Open No. 58-91338, the first fuel injection is performed simultaneously for all the cylinders at the start of the operation of the ignition switch, and any fuel injection is performed from immediately after the start until each cylinder passes one intake stroke. The valve is not operated, and the second and subsequent fuel injections are performed in a predetermined sequence immediately after each one of the intake strokes, so that the fuel is injected twice or once when the fuel is supplied to each cylinder immediately after the start. It has been proposed to prevent the fuel from not being injected even twice, but in any case, since simultaneous injection is performed in all cylinders at the time of starting, it is possible to inject and supply the fuel based on the latest data to each cylinder. The advantage of is lost.

In view of the above conventional problems, it is an object of the present invention to enable the sequential injection by making it possible to determine the cylinder to which fuel should be injected from the beginning of starting.

[0009]

To this end, the present invention, as shown in FIG. 1, includes a fuel injection valve for each cylinder in the intake system, and cylinder discrimination means for discriminating the cylinder to which fuel should be injected. In a multi-cylinder internal combustion engine including a fuel injection control unit that causes each fuel injection valve to perform fuel injection based on the determination result, an engine stop position storage unit that stores an engine stop position when the engine is stopped, and the engine stop position storage unit when the engine is started. A start-time cylinder injection determination device that determines a cylinder to be injected with fuel based on the stored contents of the storage device is provided to configure a start-time fuel injection control device.

[0010]

In the above construction, when the engine is stopped, the engine stop position at that time is stored and held, and when the engine is started thereafter, the stored contents are read out, and the cylinder discrimination is started based on this. As a result, it is possible to know the cylinder to which fuel should be injected from the beginning at the time of starting, and it becomes possible to perform sequential injection.

[0011]

EXAMPLES Examples of the present invention will be described below. FIG. 2 is a system diagram of an embodiment of the present invention. The crank angle sensor 1 outputs a reference crank angle signal (REF signal) including a cylinder discrimination signal for a specific cylinder and a unit crank angle signal (ANGLE signal) as in the conventional case, and these are output to an engine control unit (ECU). ) 2 is input. Then, the engine control unit 2 separately controls the operation of the fuel injection valve (injector) 3 provided for each cylinder.

Here, the engine control unit 2
Signals from the ignition switch 5 and the start switch 6 are input to the CPU 4 so that the ignition switch 5 can detect a stop operation and the start switch 6 can detect a start operation. Main power is supplied from the battery to the CPU 4 of the engine control unit 2 via the power relay 7, and the CPU 4 is turned on / off.
A power relay control terminal 8 is provided.

Power is directly supplied to the memory 9 of the engine control unit 2 from a battery, so that the contents stored in the memory 9 are retained even when the engine is stopped. Here, the CPU 4 of the engine control unit 2 executes the routines of FIGS.

The routine of FIG. 3 is an interrupt routine based on the REF signal from the crank angle sensor 1. In step 1 (indicated as S1 in the figure. The same applies hereinafter), REF
The value of the cylinder discrimination counter C that counts the signal is incremented. Next, in step 2, it is determined whether or not the REF signal is a cylinder discrimination signal having a long pulse width. If it is the cylinder discrimination signal, the value of the counter C is cleared in step 4.

Further, in step 3, it is determined whether or not the value of the counter C has reached 6 in order to prevent erroneous determination in step 2, and in the case of 6, the value of the counter C is cleared in step 4. The above corresponds to the cylinder discrimination means. Next, in step 5, the fuel injection cylinder is determined according to the value of the counter C, and the drive pulse signal is output to the corresponding fuel injection valve 3. This portion corresponds to the fuel injection control means.

In step 6, the timer TIMER
To reset. This meaning will be described later. The routine of FIG. 4 is a routine that is executed at regular intervals and substantially functions when the engine is stopped. This routine corresponds to the engine stop position storage means. In step 11, it is determined whether or not the ignition switch 5 is OFF, and if it is ON, the process proceeds to step 12, the flag FLAG1 is set to 0, and this routine is ended.

If the ignition switch 5 is off, the process proceeds to step 13. In step 13, the flag FLA
If the value of G1 is judged and FLAG1 = 0 (ignition switch is OFF for the first time), proceed to step 14 to set FL.
Set AG1 = 1, and in the next step 15, timer TIM
Reset ER. If FLAG1 = 1 (Ignition switch is OFF, but not the first time), the routine proceeds to step 16 and the timer TIMER is incremented.

The value of the timer TIMER measures the elapsed time from the time when the ignition switch 5 is turned off, and is reset in synchronization with the REF signal in step 6 of the routine of FIG. 3 described above. From that,
The latest RE that occurred after the ignition switch was turned off
It indicates the elapsed time from the F signal. Therefore, when the value of this timer TIMER becomes a predetermined value or more,
It is possible to detect that the generation interval of the REF signal becomes long and the next REF signal does not enter, that is, the engine stops.

Therefore, in step 17, the timer TIM
By comparing the value of ER with a predetermined value, if one second or more has elapsed from the generation of the REF signal, it is considered that the engine has stopped and the routine proceeds to step 18. In step 18, the current value of the cylinder discrimination counter C (engine stop position) counted by the routine of FIG. 3 is stored in the memory 9.
Then, after this, in step 19, the power supply relay 7 is controlled to the OFF state, and the main power supply to the CPU 4 is turned off.

As a result, the engine stop position when the engine is stopped is stored and held in the memory. The routine of FIG. 5 is a routine that is executed at regular intervals and substantially functions when the engine is started. This routine corresponds to the starting cylinder discriminating means. In step 21, it is determined whether or not the start switch 6 is ON, and if it is OFF, the routine proceeds to step 22 and the flag FLAG2 is set to 0, and this routine is ended.

If the start switch 6 is ON, the process proceeds to step 23. In step 23, the value of the flag FLAG2 is determined. If FLAG2 = 0 (start switch ON first time), the process proceeds to step 24, FLAG2 = 1 is set, and in the next step 25, the engine stored in the memory 9 is set. The value of the cylinder discrimination counter C at the time of stop is read and the value of the counter C is set.

If FLAG2 = 1 (the start switch is ON, but not the first time), this routine is finished as it is. Therefore, after that, the REF
By executing the routine of FIG. 3 in synchronization with the generation of the signal, the value of the cylinder discrimination counter C is updated. By determining the fuel injection cylinder according to the value of this counter C, it is possible at the time of start-up. Cylinder discrimination becomes possible until the cylinder discrimination signal appears in the REF signal, and sequential injection can be performed correctly.

[0023]

As described above, according to the present invention, it is possible to inject fuel into an appropriate cylinder by a sequential injection method from the beginning when the engine is started, and it is possible to prevent the emission of harmful exhaust substances. ..

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention.

FIG. 2 is a system diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart of an interrupt routine using a REF signal.

FIG. 4 is a flowchart of a routine executed when the engine is stopped.

FIG. 5 is a flowchart of a routine executed when the engine is started.

FIG. 6 is a system diagram of a conventional example.

FIG. 7 is a diagram showing how sequential injection is controlled.

FIG. 8 is a detailed view of FIG. 7.

FIG. 9 is a diagram showing a state of control when simultaneous injection is performed in all cylinders at the time of starting.

[Explanation of reference numerals] 1 crank angle sensor 2 engine control unit 3 fuel injection valve 4 CPU 5 ignition switch 6 start switch 7 power relay 8 power relay control terminal 9 memory

Claims (1)

[Claims] 1. A cylinder discriminating means for discriminating a cylinder to which fuel is to be injected, the intake system being provided with a fuel injection valve for each cylinder.
In a multi-cylinder internal combustion engine including a fuel injection control unit that causes each fuel injection valve to inject fuel on the basis of this determination result, a startup fuel injection control device that determines and controls a cylinder to which fuel should be injected at startup Therefore, the engine stop position storage means for storing the engine stop position when the engine is stopped, and the starting cylinder discriminating means for discriminating the cylinder to which fuel should be injected based on the stored contents of the storage means at the time of starting the engine are provided. A fuel injection control device for starting a multi-cylinder internal combustion engine, which is characterized.