JPS603456A - Fuel feed controlling method for multicylinder internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent a fuel injection quantity from oversupplying in time of engine starting, by opening all fuel injection valves simultaneously when operating voltage is more than the specified one, then reducing the injection numbers of these valves, and further making them perform their valve opening in regular sequence. CONSTITUTION:When operating voltage for the central processing unit of an electronic control unit 5 is more than the specified one in time of starting, all cylinders are made to do a sequent injection successively for some time till a cylinder discrimination signal is first inputted. After starting, whether the cylinder discrimination signal is inputted more than twice or not, and when ''NO'' is the case, the number of cylinders to be subject to the sequent injection is reduced but when ''YES'' is the case, they are made to do each injection in regular sequence. With this constitution, oversupply in the fuel injection quantity in time of starting is preventable and, what is more, engine driving can be continued in succession even in time of a drop in the battery voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control method for a multi-cylinder internal combustion engine, and more particularly to a fuel supply control method during startup.

A fuel supply control method in which an electronic fuel injection control device electrically calculates the amount of fuel to be supplied to an internal combustion engine based on a parameter signal representing the operating state of the engine includes a central processing unit built in the electronic fuel injection control device. The injection order is determined by a cylinder discrimination signal generated once per cycle of the engine at a predetermined position on the crankshaft of the engine, and a timing signal indicating the predetermined position of the crankshaft corresponding to the injection timing of each cylinder is generated. There is a fuel supply control method that sequentially injects and supplies fuel to each cylinder. There is also a fuel supply control method that simultaneously injects fuel into all cylinders using the first timing signal during startup.

By the way, when the starter is driven when starting the engine, especially during a cold start, the battery voltage decreases, and as a result, it may drop below the operating voltage of the central processing unit that controls the amount of fuel to each cylinder. Sometimes, the terminal voltage of the starter, that is, the battery voltage fluctuates pulsatingly, and as a result, the central processing unit injects fuel into all cylinders at every injection timing signal after the battery voltage returns to the operating voltage of the central processing unit. The next fuel will be injected while the previously injected fuel has not yet been injected. Therefore, if such an operation is repeated two or three times, there is a risk of excess fuel, that is, over-richness, and there are problems such as a decrease in engine startability.

The present invention was made in view of the above points, and aims to prevent excessive fuel injection amount (hereinafter referred to as overrich) at the time of starting, and to obtain good starting performance even against battery voltage drop. purpose.

In order to achieve this object, in the present invention, the injection order is determined by the cylinder discrimination signal that is generated once per cycle of the engine at a predetermined position on the crankshaft of the engine by the central processing unit of the electronic control unit. In a fuel supply control method for a multi-cylinder internal combustion engine that sequentially injects fuel to each cylinder each time a timing signal indicating a predetermined position of the crankshaft corresponding to the injection timing of the cylinder is generated, the operation supplied to the central processing unit detecting the voltage, and when the operating voltage is equal to or higher than a predetermined voltage, all the fuel injection valves are opened simultaneously every time the timing signal is input until the cylinder discrimination signal is first input after startup;
After inputting the first cylinder discrimination signal, the number of operations of the fuel injection valve is gradually decreased every time the timing signal is input, and the second cylinder discrimination signal is inputted.
A fuel supply control method for a multi-cylinder internal combustion engine in which fuel injection valves corresponding to each timing signal are sequentially opened from the timing signal after the input of the th cylinder discrimination signal, and an operating voltage supplied to the central processing unit is provided. When the operating voltage is equal to or higher than a predetermined voltage, all the fuel injection valves are opened simultaneously every time the timing signal is input until the cylinder discrimination signal is input for the first time after starting, and the first cylinder is opened. After the discrimination signal is input, the number of fuel injection valves to be operated is gradually decreased each time the timing signal is input, and from the timing signal after the second cylinder discrimination signal is input, the fuel injection valves corresponding to each timing signal are sequentially operated. A fuel supply control method for a multi-cylinder internal combustion engine in which the valves are opened, and when the operating voltage does not reach a predetermined voltage, all fuel injection valves are simultaneously opened for each timing signal in response to the timing signal by a constant voltage operating circuit. It provides:

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an overall configuration diagram of a fuel supply control device according to the present invention, in which an engine 1 is a multi-cylinder engine, for example a four-cylinder engine, equipped with a sub-combustion chamber, and an intake pipe 2 is connected to each main combustion chamber. A sub-intake pipe 2 communicating with the main intake pipe 2a and each sub-combustion chamber
b, and a throttle body 3 is located in the middle of the intake pipe 2.
A main throttle valve 3a and a sub-throttle valve 3 are provided in the main intake pipe 2a and the sub-intake pipe 2b, respectively.
b are provided in conjunction with each other. A throttle valve opening sensor 4 is connected to the main throttle valve 3a, converts the valve opening of the main throttle valve 3a into an electrical signal, and supplies the electrical signal to an electronic control unit (hereinafter referred to as ECU) 5.

Main fuel injection valves 6 are provided in the main intake pipe 2a and the auxiliary intake pipe 2b, respectively.
and an auxiliary fuel injection valve 7 are provided, the main fuel injection valve 6 being located slightly upstream of an unillustrated intake valve in the main intake pipe 2a for each cylinder, and the auxiliary fuel injection valve 7 being one in the auxiliary intake pipe 2b. A valve C is provided in common to each cylinder slightly downstream of the sub-throttle valve 3b. The main fuel injection valve 6 and the auxiliary fuel injection valve 7 are each connected to a fuel pump (not shown) and are electrically connected to the ECU 5, and the opening time of fuel injection is controlled by a control signal from the ECU 5. . Throttle valve 3a
An absolute sensor 9 is provided immediately downstream of the ECU 5 via a pipe 8, and is connected to the ECU 5.

The main body of the engine 1 is provided with an engine water temperature sensor 10. The sensor 10 is made of a thermistor or the like, and is mounted in the circumferential wall of the engine cylinder filled with cooling water, and supplies a detected water temperature signal to the ECU 5. In addition, an engine speed sensor (hereinafter referred to as TDC sensor) 11 and a cylinder discrimination sensor (hereinafter referred to as C
YL sensor) 12h is attached around the camshaft or distributor shaft (not shown) of the engine 1, and the TDC sensor 11 sends a timing signal indicating a predetermined position of the crankshaft corresponding to the injection timing of each cylinder. The CYL sensor 12 generates a cylinder discrimination signal once per cycle of the engine at a predetermined position of the crankshaft. These timing signals and cylinder discrimination signals are supplied to the ECU 5.

The ECU 5 is connected to a battery 17 via an ignition switch 16a of the key switch 16, and is supplied with operating voltage from the battery 17 when the ECU 5 is turned on. The starter 18 is connected to the battery 17 via a starter switch 16b of the key switch 16. Further, the connection point between the starter 18 and the key switch 16b is connected to the ECU, so that the ECU 5 detects the terminal voltage of the starter 18 on the battery at the time of starting, that is, the battery voltage at the time of starting.

The second is a flowchart showing the procedure of the control method of the present invention, which will be explained with reference to the timing chart of FIG.

The power supply voltage supplied to the ECU 5 at the time of starting is
It is determined whether the voltage is higher than the operating voltage of the central processing unit in the CU (step 20), and if the answer is negative (No), backup is performed simultaneously based on other electronic circuits without being controlled by the central processing unit. Injection (Fig. 4(d), (e)) is performed (step 22). When the answer is affirmative (Yes), it is determined whether the cylinder discrimination signal CYL has been input even once after starting (step 23), and the answer is negative (No).
When the TDC signal is input, simultaneous injection is performed in all cylinders (Fig. 4 (a), (b), (d), and (c) (step 24), and the value i is set to a predetermined value 4. Set to (
Step 25). This value 4 may be a value corresponding to the number of cylinders, or may be set to any integer larger than the number of cylinders.

If the answer to step 23 is affirmative (Yes), C after startup.
It is determined whether or not the YL signal has been input twice or more (step 26), and if the answer is negative (No), the number of cylinders in which simultaneous injection is performed is reduced (step 27) and affirmative (Yes).
When , the fuel is injected sequentially (step 28).

The control to reduce the number of simultaneous injection cylinders in step 27 is performed in the third step.
This is done according to the flowchart in the figure. That is, the predetermined value i
is 4 or not (step 30), and if the answer is affirmative (Yes), the timing input immediately after the cylinder discrimination signal CYL1 (Fig. 4 (a)) is input for the first time after starting. Cylinder number #1, 3, by signal TDC
4, Simultaneous injection to all cylinders shown in 2 (Fig. 4 (b), (c)
) (step 31), and the value l is subtracted from the predetermined value i (=4) (step 32). If the answer to step 30 is negative (No), it is determined whether the value i is 3 or not (step 33), and if the answer is 11 constant (Yes), it is determined that it is the second simultaneous injection and the first The simultaneous injection (FIG. 4(e)) is performed in the other cylinders #3, 4, and 2 except for the cylinder #l, and the process proceeds to step 32.

When the answer to step 33 is negative (No), it is determined whether or not the predetermined value i is 2 (step 35), and when the answer is affirmative (Yes), it is determined that it is the third simultaneous injection. The other cylinder #4 except the first and second cylinders #1 and 3
, 2, simultaneous injection (Fig. 4(e)) is performed (step 36
), proceed to step 32. The answer to step 35 is negative (N
o), fuel is injected into the remaining cylinder #2 (FIG. 4(e)) excluding the cylinders #1, 3 and 4, and step 32
Proceed to.

As described above, the TDC signal immediately after the CYL1 signal input after startup performs simultaneous injection into the gold cylinder, and the second
Until the CYL2 (FIG. 4(a)) signal is input, the number of cylinders in which simultaneous injection is performed is gradually decreased each time the TDC signal is input. When the second CYL signal is input after starting, injections are sequentially performed in a predetermined order (FIG. 4(e)) every time the timing signal TI)C is input. Note that the sub-injection valve is driven every time the timing signal TDC is input, regardless of the cylinder discrimination signal CYL.

FIG. 5 shows a circuit configuration inside the ECU that is not shown in FIG. 1.

Ignition switch 1 that constitutes key isochi 16
When 6a is turned on, the power supply voltage of the battery 17 is supplied to the constant voltage circuit 501, and the constant voltage circuit 501 outputs a constant voltage Vcc. This constant voltage Vcc is supplied to the main calculation control circuit 503 and the electrification drop detection circuit 502.

'The trigger signal output from the TDC sensor 12 (FIG. 6(a)) is supplied to the one-shot circuit 504, and the output pulse signal of this one-shot circuit 504 (FIG. 6(b)) is supplied to the one-shot circuit 504.
) are the delay circuit 505a of the low voltage operation circuit 505, the one-shot circuits 505b, 505c, the integration circuit 505d,
505e and the main operation control circuit 503. The output signal of the water temperature sensor 10 is supplied to the main calculation control circuit 503 and the non-inverting input terminal of the comparator 505b of the low voltage operation circuit 505.

The main calculation control circuit 503 receives TI input from the one-shot circuit 504 based on engine parameter signals output from various sensors such as the water temperature sensor 10 shown in FIG.
Each time the pulse h:'' synchronized with the C signal is input, the opening times T OUT M' and T OUT of the main fuel injection valve and the auxiliary fuel injection valve are expressed by the following equations (1) and (2).
S is calculated and a corresponding valve opening control signal is output.

T OUT M=TiM×K1+TK2...(1)T
OUT S=Tis×K'1+TK'2...(2)
Further, the main calculation control circuit 503 calculates a valve opening time T OUT M' for performing simultaneous injection at the time of starting, and outputs a corresponding staggered valve opening control signal. The valve-opening time during this simultaneous injection is set to a predetermined times the valve-opening time during normal operation, for example, 1/4 times the number of cylinders, ie, 1/4 times in the case of 4 cylinders.

T OUT M'=(TiM×Kl)/4+TK2...
-(3) Here, TiM and Tis indicate the basic injection times of the main fuel injection valve 6 and the secondary fuel injection valve 7, respectively, and these basic fuel injection times are, for example, based on the intake internal absolute pressure PBA and the engine It is calculated according to the rotational force Ne.

The coefficients K1, K'1 and correction values TK2, TK'2 are correction coefficients and correction values that are calculated according to the engine parameter signals from each sensor mentioned above, and especially the correction value TK2.
, TK'2 is a voltage correction value, which is calculated based on a predetermined calculation formula so that various characteristics such as starting characteristics, exhaust gas characteristics, fuel consumption characteristics, and engine acceleration characteristics are optimized according to the engine operating condition. Calculated.

The valve opening control signal for the main fuel injection valve 6 is outputted separately for the main fuel injection valve 6a to 6d of each cylinder, and as described later, AND circuits 521 to 525 are successively opened each time a TDC signal is generated.
24 and each drive circuit 5 via OR circuits 526 to 529.
31 to 534 are sequentially supplied. Each drive circuit 531-5
37I outputs an opening drive signal into which the valve opening signal layer is input to open the corresponding main fuel injection valves 6a to 6d.

On the other hand, the valve opening control signal for the auxiliary fuel injection valve 7 is output every time the TDC signal is input, and is supplied to the drive circuit 530 via the AND circuit 520 and the OR circuit 525 which are in the open state, as will be described later. This drive circuit 530 outputs a drive signal to control the opening of the auxiliary fuel injection valve 7 while the valve opening signal is being input.

The voltage drop detection circuit 502 determines whether the output voltage Vcc of the constant voltage circuit 501 is equal to or higher than a predetermined voltage (operating voltage) at which a central processing circuit (not shown) (hereinafter referred to as CPtJ) in the main arithmetic and control circuit 503 can operate normally. When the voltage is above a predetermined voltage, a low level signal is output, and when the voltage is below a predetermined voltage, a high level signal is output. The output signal of this voltage drop detection circuit 502 is supplied to one input terminal of AND circuits 520 to 524 via a main operation control circuit 503, one input terminal of AND circuits 511 to 515, and an inverter 508.

Therefore, when the output of the voltage drop detection circuit 502 is at a low level, the AND circuits 520 to 524 are operated by the constant voltage circuit 5
When the output voltage Vcc of 01 is higher than the operating voltage of the CPU, it is in an open state, and when it is at a high level, that is, when the voltage Vcc is lower than the operating voltage of the CPU, it is in a closed state. On the contrary, the AND circuits 511 to 515 are the voltage drop detection circuit 502
When the output of constant voltage circuit 501 is at a high level, that is, when the output voltage Vcc of the constant voltage circuit 501 is lower than the operating voltage of the CPU, it is in a closed state, and when it is at a low level, it is in an open state.

The low-voltage control circuit 505 is configured to operate at a voltage lower than the operating voltage of the CPIJ, and the delay circuit 505a delays the timing signal, that is, the TDC signal input from the one-shot circuit 504, by a predetermined time. and supplies it to one-shot circuits 505b and 505c. The one-shot circuit 505b is used to set the opening time of the auxiliary fuel injection valve after startup when the low-voltage control circuit 505 is activated, and when a pulse signal is input from the delay circuit 505a, ), a pulse signal with a time width corresponding to the opening time of the auxiliary fuel injection valve after startup is output and supplied to one input terminal of the ant circuit 505k.

The one-shot circuit 505c is a low voltage control circuit 5()5
This is to set the opening time of the main and auxiliary fuel injection valves for starting during operation, and the opening time of the main fuel injection side valve after starting. A pulse signal is output and supplied to integration circuits 505d and 505c. The one-shot circuits 505b and 505c restart 1 with the TDC signal when the output time becomes longer than the interval of the TDC signal.
It is reset by the output pulse of the one-shot circuit 504 in order to reset.

The integral circuit 505d is for setting the opening time of the main and auxiliary fuel injection valves for starting, and the opening time is the opening time of the main fuel injection side valve during sequential injection control by the main calculation control circuit 503. The integral time constant is set to be small, for example, 1/4 of the number of cylinders (FIG. 6(e)).

The integral circuit 505e is used to set the main fuel injection time after starting, and its integral constant is set to be sufficiently large compared to the time constant of the integral circuit 505d, for example, the number of cylinders (Fig. 6). (f)).

The output voltages of the integrating circuits 505d and 505e are respectively applied to field effect transistors (hereinafter referred to as transistors) 505.
f and 505g to the inverting input terminal of the comparator 505h. As described above, the output voltage of the engine coolant temperature sensor 10 is supplied to the non-inverting input terminal of the comparator 505h. Each of these transistors 505f, 505g
The conduction (on) or non-conduction (off) of the engine is determined depending on whether the engine is being started or after it has been started.

Immediately, operate the key switch 16 to turn on the starter switch 1.
6b is turned on and the starter 18 is operating to start the engine 1, the output of the level correction circuit 505 becomes high level, is inverted by the inverter 507 and becomes low level, turning off the transistor 505g, and the output of the inverter 505i is inverted and becomes a high level, turning on the transistor 505f. Therefore, during engine starting, the output voltage of the integrating circuit 505d is the same as that of the transistor 50.
It is supplied to a comparator 505h via 5f. When the key switch 16b is opened (turned off) after starting the engine, the output of the level correction circuit 506 becomes low level, and contrary to the above, the transistor 505f is turned off and the transistor 5
05g is turned on. Therefore, after starting, the integration circuit 505
The output voltage of e is connected to the comparator 5 via the transistor 505g.
Supplied at 05h.

The output of the comparator 505b remains at a high level while the output voltage of the temperature sensor 10 is higher than the output voltage of the integrating circuit 505d or 505e. The lower the engine water temperature, the lower the water temperature sensor 10
The output voltage of the comparator 505h increases, and the high level output time of the comparator 505h increases accordingly. This comparator 505h
The output signal of the one-shot circuit 505c is in the open state while the output is at a high level, and is supplied to the AND circuits 512 to 515 via the AND circuit 505m, and the AND circuits 512 to 5]5 are in the open state. Along with the shift, the AND circuit 5 remains open while the transistor 505f is on.
05n and the ant circuit 51 via the OR circuit 505p.
1.

Further, the output of the one-shot circuit 505h and the output of the bell correction circuit 506 become low level, and the transistor 505
When e is on, that is, after starting, the signal is supplied to the AND circuit 511 via the AND circuit 505k and the OR circuit 505p, which are open.

The output voltage V of the constant voltage circuit 501 when starting the engine
As described above, when cc is equal to or higher than the operating voltage of the CPU, the output of the voltage drop detection circuit 502 becomes low level,
AND circuits 520 to 524 are opened. Therefore,
The valve opening signal of the auxiliary fuel injection valve 7 output from the main calculation control circuit 503 is supplied to the auxiliary fuel injection valve drive circuit 530 via the AND circuit 520 and the OR circuit 525, and the valve opening signal of each main fuel injection valve is AND circuits 521 to 524, OR circuit 5
Main fuel injection side valve drive circuits 531 to 5 via 26 to 529
34.

The main arithmetic control circuit 503 receives a timing signal TD at the time of starting.
Each time C is input, the valve opening time shown by the above-mentioned formula (3) is calculated, the corresponding valve opening signal is output, and the signal is supplied to the sub and main fuel injection valve drive circuits 503 and 531 to 534 to inject all the fuel. The injection valves are sent out simultaneously (Fig. 4(e)).

The main calculation control circuit 503 performs the simultaneous injection until the first cylinder discrimination signal CYL is input after the start J+.

Immediately after the first CYL signal CYL1 (Fig. 4 (a)) is input after starting, the timing signal TDC (Fig. 4 (b)) input immediately after the first CYL1 signal is inputted sequentially. Gradually reduce the number of operations of the main fuel injection valve (4th
Figure (e)). Then, the second CYL signal CYL2(
After the input of Fig. 4(a), each timing signal TD
The fuel injection valves corresponding to C are sequentially opened and injection control is performed sequentially (FIG. 4(e)).

The valve opening time of the main fuel injection valve after startup until the transition to the sequential injection control is controlled to be the same as the valve opening time at startup, and the valve opening time, that is, the fuel injection amount, is controlled to be the same as the fuel injection amount during sequential injection. 1/4 of the amount, and the total for one cycle corresponds to the amount that should normally be injected. Therefore, the amount of fuel supplied to each cylinder during simultaneous injection does not become excessive.

By the way, when the output voltage Vcc of the constant voltage circuit 501 is lower than the operating voltage of the CPU when the engine is started (in some cases, the output of the voltage drop detection circuit 502 becomes high level, the AND circuits 511 to 515 are opened, and the ant circuit 52
0 to 524 are in the open state. On the other hand, at startup, the transistor 505f is turned on and the integrated voltage of the integrating circuit 505d is supplied to the comparator 505h. e)) reaches a high level (Fig. 6 (g)
)). The output of this comparator 505h is the AND circuit 505m
While in the open state, the fuel is supplied from the AND circuit 505m to the main fuel injection valve drive circuits 531 to 534 via the AND circuits 512 to 515 and the OR circuits 526 to 529 (FIG. 6(h)). At the same time, the output of the AND circuit 505m is also supplied to the auxiliary fuel injection valve drive circuit 530 via the AND circuit 505n, the OR circuit 505p, the ant circuit 511, and the OR circuit 525.

Thus, while the output of the comparator 505h is at a high level, the main fuel injection valves 6a to 6d and the auxiliary fuel injection valve 7 are controlled to open simultaneously and for the same period of time. That is, all the fuel injection valves inject simultaneously. As described above, the valve opening time at this time is 1/4 of the valve opening time of the main fuel injection valve during normal operation.

Therefore, even if the output voltage Vcc of the constant voltage power supply circuit 501 becomes equal to or lower than the operating voltage of the CPU synchronously during startup, excess fuel will not occur because the valve opening time is 1/4.

Furthermore, when the output voltage Vcc of the constant voltage circuit 501 drops below the operating voltage of the CPU due to some abnormality during operation after starting the engine, the transistor 505g is turned on and the integrated voltage of the integrating circuit 505e is supplied to the comparator 505. The output of the comparator 505h remains at a high level while the integrated voltage is lower than the water temperature sensor output voltage (FIG. 6(f)) (as shown by the broken line in FIG. 6(g)). This comparator 505h
is output from the AND circuit 505m while the AND circuit 505m is in the open state (shown by a broken line in FIG. 6(h)), and the AND circuits 512 to 515 and the OR circuits 526 to
529 to each main fuel injection valve drive circuit 531 to 534
is supplied to each main fuel injection valve 6a to 6d to cause simultaneous injection. The injection time of the main fuel injection valves 6a to 6b at this time is approximately equal to the valve opening time during the reciprocating operation.

On the other hand, the output pulse signal of the one-shot circuit 505b is supplied to the auxiliary fuel injection valve driving side valve 530 via the AND circuit 505k, the OR circuit 505p, the AND circuit 511, and the OR circuit 525, which are in an open state during normal operation. While the output pulse of the circuit 505b is at a high level (
FIG. 6(c)) Opening control of the auxiliary fuel injection valve 7 is performed. The valve opening time at this time, that is, the pulse time of the one-shot circuit 505b, is set to be approximately equal to the valve opening time of the auxiliary fuel injection valve during the normal operation.

Therefore, during operation, the output voltage Vcc of the constant voltage circuit 501
Even if the voltage drops below the operating voltage of the CPU, the engine can continue to operate.

In addition, the water temperature sensor 1 is connected to the non-inverting input terminal of the comparator 505h.
Instead of the output signal 1, other signals such as a throttle valve opening signal representative of the amount of intake air or a parameter signal such as an intake pipe absolute pressure signal may be used.

Furthermore, when the low-voltage operation circuit 505 is activated, the opening time of the auxiliary fuel injection valve after the engine starts is set to be constant regardless of the engine water temperature. The valve opening time may be set in accordance with a parameter value or the like.

As explained above, according to the present invention, the injection order is determined by the cylinder discrimination signal that is generated once per cycle of the engine at a predetermined position on the crankshaft of the engine by the central processing unit of the electronic control unit. A fuel supply control method for a multi-cylinder internal combustion engine in which fuel is sequentially injected into each cylinder each time a timing signal indicating a predetermined position of the crankshaft corresponding to the injection timing of the cylinder is generated,
The voltage supplied to the central processing unit is detected, and when the voltage is equal to or higher than a predetermined voltage, all fuel injection valves are activated every time the timing signal is input until the cylinder discrimination signal is input for the first time after starting. are opened at the same time, the number of operations of the fuel injection valve is gradually decreased every time the timing signal is input after the input of the first cylinder discrimination signal, and the number of operations of the fuel injection valve is gradually decreased from the timing signal after the input of the second cylinder discrimination signal. Since the fuel injection valves corresponding to the timing signals are sequentially opened, it is possible to prevent an excessive amount of fuel injection at the time of starting.

Furthermore, the operating voltage supplied to the central processing unit is detected, and when the operating voltage is equal to or higher than a predetermined voltage, the entire operation is performed every time the timing signal is input from the start until the cylinder discrimination signal is input for the first time. Open the fuel injection valves at the same time,
After the input of the first cylinder discrimination signal, the number of operations of the fuel injection valve is gradually decreased every time the timing signal is input, and a second cylinder discrimination signal is input.
The fuel injection valves corresponding to the respective timing signals are sequentially opened from the timing signal after the input of the th cylinder discrimination signal, and when the operating voltage does not reach a predetermined voltage, the constant voltage operating circuit operates in response to the timing signal. Since all fuel injection valves are opened at the same time for each timing signal, it is possible to obtain good starting performance even in the event of a battery voltage drop, and the engine can be maintained even when the battery voltage drops during operation. can continue to operate.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a fuel supply control device to which the present invention is applied, FIGS. 2 and 3 are flowcharts showing the procedure of the control method of the present invention, and FIGS. FIG. 5 is a block diagram showing an example of the internal configuration of the electronic control unit (ECU) of FIG. 1, and FIG. a) to (h) are timing charts of output signals of each part in FIG. 5. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 5... Electronic control unit, 6, 6a-6d... Main fuel injection valve, 7... Sub-fuel injection valve, 10... Water temperature sensor, 11... Engine rotation Number of sensors, 12... Cylinder discrimination sensor, 16...
・Key switch, 17... Battery, 502... Voltage drop detection circuit, 503... Main calculation control circuit, 505
...Low voltage operating circuit. Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshihikote Watanabe Masashi Ura (Method) Patent Application No. 1, 1981] 166832, Title of Invention Cooking of multi-cylinder internal combustion engine: 1 Supply control method 3 , make amendments, 15 ・11 agent 340-

Claims (1)

[Claims] 1. The central processing unit of the electronic control unit determines the injection order based on a cylinder discrimination signal that is generated once per cycle of the engine at a predetermined position on the crankshaft of the engine, and determines the injection timing for each cylinder. A fuel supply control method for a multi-cylinder internal combustion engine in which fuel is sequentially injected into each cylinder each time a timing signal indicating a predetermined position of the crankshaft corresponding to the crankshaft is generated, the method comprising detecting an operating voltage supplied to the central processing unit. When the operating voltage is equal to or higher than a predetermined voltage, all fuel injection valves are opened simultaneously every time the timing signal is input until the cylinder discrimination signal is input for the first time after starting, and the first cylinder discrimination signal is After the input, the number of operations of the fuel injection valves is gradually decreased every time the timing signal is input, and the fuel injection valves corresponding to each timing signal are sequentially opened from the timing signal after the second cylinder discrimination signal is input. A fuel supply control method for a multi-cylinder internal combustion engine, characterized in that: 2. The central processing unit of the electronic control unit determines the injection order based on a cylinder discrimination signal that is generated once per cycle of the engine at a predetermined position on the crankshaft of the engine, and In a fuel supply control method for a multi-cylinder internal combustion engine in which fuel is sequentially injected into each cylinder each time a timing signal indicating a predetermined position is generated, an operating voltage supplied to the central processing unit is detected, When the voltage is higher than the voltage, all fuel injection valves are opened at the same time every time the timing signal is input until the cylinder discrimination signal is input for the first time after starting, and the timing is changed after the input of the first cylinder discrimination signal. The number of operations of the fuel injection valves is gradually decreased each time a signal is input, and the fuel injection valves corresponding to each timing signal are sequentially opened from the timing signal after the input of the second cylinder discrimination signal, and the operation voltage is increased. A fuel supply control method for a multi-cylinder internal combustion engine, characterized in that when a predetermined voltage is not reached, all fuel injection valves are simultaneously opened for each timing signal in accordance with the timing signal by a low voltage operating circuit.