JPH0366504B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control method for a multi-cylinder internal combustion engine, and in particular, when a calculation control circuit that controls the amount of fuel supplied to a combustion chamber according to the operating state of the engine loses its normal function. The present invention relates to a fuel supply control method including a compensation control method.

The amount of fuel supplied to an internal combustion engine, especially a gasoline engine, is set to a standard value depending on, for example, the engine speed and the absolute pressure inside the intake pipe. controlling the fuel supply amount by electronically adding and/or multiplying constants and/or coefficients depending on pressure, engine water temperature, throttle valve opening, exhaust concentration (oxygen concentration), etc.;
The present applicant has proposed a fuel supply amount control method that controls the air-fuel ratio of the air-fuel mixture supplied to the engine (Japanese Patent Application No. 56-023994).

In this fuel supply amount control method, when starting the engine, especially when starting in a cold state, the battery voltage decreases due to starter operation, etc., and the amount of fuel supplied to the combustion chamber of each cylinder is controlled due to this decrease in battery voltage. There may be cases where the arithmetic and control circuit that operates the engine cannot operate normally and cannot appropriately control the amount of fuel supplied. In addition, even if the arithmetic control circuit deviates from the predetermined program procedure due to disturbances such as noise and does not execute a predetermined operation within a predetermined time, which is a so-called "runaway" state, it is possible to control the supply of an appropriate amount of fuel to the engine. becomes impossible. If some measure is not taken in such a case, the engine will not be able to start and will have a serious impact on driving performance.

The present invention has been made to solve the above-mentioned problems, and according to the first invention, there is provided a fuel supply control method for electronically controlling the amount of fuel supplied to a multi-cylinder internal combustion engine having a combustion chamber for each cylinder. , detecting a power supply voltage value of a main arithmetic control circuit that sequentially outputs a first control signal for controlling the amount of fuel supplied to the combustion chamber according to a predetermined cylinder order, and detecting a power supply voltage value when the voltage value becomes a predetermined value or less and whether a predetermined period of time has elapsed without the main arithmetic and control circuit performing a predetermined operation, and when either of these conditions is met, an output is output from the main arithmetic and control circuit. A second control signal outputted from the auxiliary control circuit is used as an alternative control signal in place of the first control signal, and the alternative control signal is simultaneously outputted from the auxiliary control circuit to all the cylinders so that the second control signal is outputted to each cylinder simultaneously. A fuel amount is supplied to the combustion chamber according to the second control signal, and the fuel supply amount to the combustion chamber based on the second control signal is set to one of parameter values representing engine temperature and intake air amount. Provided is a fuel supply control device method for a multi-cylinder internal combustion engine, characterized in that the fuel supply control device determines the fuel supply according to the following.

Furthermore, according to the second invention, in the fuel supply control method for electronically controlling the amount of fuel supplied to a multi-cylinder internal combustion engine having a main combustion chamber and a sub-combustion chamber for each cylinder, A first control signal for controlling the amount of fuel to be supplied is sequentially output in accordance with a predetermined order of cylinders, and a second control signal for controlling the amount of fuel to be supplied to the auxiliary combustion chamber is simultaneously output to all cylinders. detecting the power supply voltage value of the main arithmetic and control circuit that operates, and determining whether or not the voltage value has fallen below a predetermined value and whether a predetermined period of time has elapsed without the main arithmetic and control circuit performing a predetermined operation; When either of these conditions is satisfied, third and fourth control signals output from the auxiliary control circuit are used instead of the first and second control signals output from the main arithmetic control circuit. These alternative control signals are used as alternative control signals, and these alternative control signals are simultaneously output from the auxiliary control circuit to all cylinders, and a third control signal and a fourth control signal are sent to the main combustion chamber and sub-combustion chamber of each cylinder, respectively. The amount of fuel is supplied according to the third
The amount of fuel supplied to the main combustion chamber based on the control signal is determined according to either one of the engine temperature and the parameter value representing the intake air amount, while the amount of fuel supplied to the auxiliary combustion chamber based on the fourth control signal is determined. There is provided a fuel supply control method for a multi-cylinder internal combustion engine, characterized in that at least when the engine is started, the fuel supply is determined according to either one of a parameter value representing an engine temperature or an intake air amount.

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

FIG. 1 is an overall configuration diagram of a fuel supply control device to which the method of the present invention is applied. Reference numeral 1 indicates, for example, a four-cylinder internal combustion engine, and in this embodiment, engine 1 has four main combustion chambers and four main combustion chambers. It is formed by a sub-combustion chamber (both not shown) communicating with the combustion chamber. An intake pipe 2 is connected to the engine 1, and the intake pipe 2 includes a main intake pipe 2a communicating with each main combustion chamber and a sub intake pipe 2b communicating with each sub combustion chamber. A throttle body 3 is provided in the middle of the intake pipe 2,
A main throttle valve 3a and a sub-throttle valve 3 are arranged inside the main intake pipe 2a and the sub-intake pipe 2b, respectively.
b are provided in communication with each other. Main throttle valve 3
A throttle valve opening sensor 4 is connected to a, which converts the valve opening of the main throttle valve into an electrical signal and controls an electronic control unit (hereinafter referred to as "ECU").
It is set to be sent to 5th.

A main fuel injection valve 26 and an auxiliary fuel injection valve 7 are provided in the main intake pipe 2a and the auxiliary intake pipe 2b, respectively. Only one auxiliary fuel injection valve 7 is provided in the auxiliary intake pipe 2b, slightly downstream of the auxiliary throttle valve 3b, in common to each cylinder.
The main fuel injection valve 6 and the auxiliary fuel injection valve 7 are each connected to a fuel pump (not shown). The main fuel injection valve 6 and the auxiliary fuel injection valve 7 are electrically connected to the ECU 5, and the opening time of fuel injection is controlled by a signal from the ECU 5.

An absolute pressure _PBA sensor 9 is provided immediately downstream of the throttle valve 3 via a pipe 8, and the ECU 5
electrically connected to. An intake temperature sensor 10 is attached to the intake pipe 2, and this intake temperature sensor 10 is electrically connected to the ECU 5 to
An intake air temperature signal is supplied to the ECU5.

The main body of the engine 1 is provided with an engine water temperature sensor 11, which is made of a thermistor or the like, and is inserted into the circumferential wall of the engine cylinder filled with cooling water, and supplies its detected water temperature signal to the EUC 5.
In addition, the engine rotation speed sensor (hereinafter referred to as "TDC sensor")
) 12 is attached around the camshaft or crankshaft (not shown) of the engine 1,
The TDC sensor 12 detects a predetermined rotational position of the engine and sends this rotational position signal (TDC signal) to the ECU 5.
supply to. An O ₂ sensor 14 is inserted into the exhaust pipe 13 , and this sensor 14 detects the oxygen concentration in the exhaust gas and supplies the detected value signal to the ECU 5 .

Further, other engine parameter sensors 15, such as an atmospheric pressure sensor, a back pressure sensor, etc., are connected to the ECU 5, and the sensors 15 supply other engine parameter signals to the ECU 5.

Furthermore, ECU5 is ignition switch 1
The ECU 5 is connected to a DC power source, for example, a battery 17, through the ECU 6a, and operating power is supplied from the battery 17 to the ECU 5 when the ignition switch 16a is turned on. Battery 17 is ignition switch 1
It is also connected to the starter 18 via the starter switch 6a and the starter switch 16b, and the ignition switch 1
The on-off status signals of starter switch 6a and starter switch 16b are supplied to EUC5. Further, an alarm device 19 is connected to the ECU 5.

Next, regarding the function of ECU 5, the ECU shown in Figure 2
A description will be given with reference to a flowchart of the general procedure of fuel supply amount control executed in 5.

First, ECU5 is the control power supply voltage inside ECU5.
It is determined whether V _CC1 is a predetermined voltage, for example, 4.75V or higher (Step 1 in FIG. 2). This predetermined voltage corresponds to the rated voltage at which the main arithmetic control circuit described later in the ECU 5 can perform normal operation, and is the power supply voltage.
If V _CC1 is below a predetermined voltage, the main arithmetic control circuit is diagnosed as having lost its normal function. If the determination result in step 1 is positive (Yes), proceed to step 2.
It is determined whether or not, for example, a watchdog timer in the ECU 5 has timed up. That is, when a predetermined control program executed by the main arithmetic and control circuit executes a predetermined operation in the control program before a predetermined period of time has elapsed, the main arithmetic and control circuit is diagnosed to be operating normally, and the predetermined operation is performed. If the program is not executed after a predetermined period of time, it is diagnosed that the program being executed in the main arithmetic and control circuit is in a so-called "runaway" state, and that the main arithmetic and control circuit has lost its normal function.

If the determination result in step 2 is negative (No),
In other words, if the watchdog timer does not indicate that the time has expired, if the main arithmetic control circuit lost its normal function in the previous loop and activated the alarm device 19, which will be described later, this alarm device The alarm is canceled by stopping the operation of the alarm (step 3), and proceeding to step 4.

In step 4, the ECU 5 calculates the fuel injection times T OUTM and _OUTM of the main fuel injector 6 and the auxiliary fuel injector 7, which are given by the following formulas, based on the various engine parameter signals and according to the engine operating state.
Calculate T _OUTS .

T _OUTM = T _iM ×K ₁ +T _K2 …(1) T _OUTS = T _iS ×K′ ₁ +T _K2 ′…(2) Here, T _iM and T _iS are the main fuel injection valve 6 and the auxiliary fuel injection valve 7, respectively. Each basic injection time is calculated according to, for example, the intake pipe absolute pressure P _BA and the engine rotation speed Ne.

The coefficients K ₁ , K′ ₁ and the correction values T _K2 , T _K ′ ₂ are determined by the various sensors described above, namely, the intake pipe absolute pressure sensor 9,
intake temperature sensor 10, engine water temperature sensor 11,
Ne sensor 12, throttle valve opening sensor 4, O ₂
Sensor 14 and other engine parameter sensors 1
Correction coefficients and correction values calculated according to engine parameter signals from 5, and are predetermined so that various characteristics such as starting characteristics, exhaust gas characteristics, fuel efficiency characteristics, engine acceleration characteristics, etc. are maximized according to engine operating conditions. It is calculated based on the calculation formula.

The ECU 5 supplies each fuel injection valve 6 and 7 with a drive signal to open the main fuel injection valve 6 and the auxiliary fuel injection valve 7, respectively, based on the fuel injection times T _OUTM and T _OUTS determined as described above. . Figure 3 a is TDC
This figure shows how the above-mentioned drive signal is generated every time a signal is generated, and the drive signal for the main fuel injection valve 6 is
Each time the TDC signal is generated, it is generated sequentially according to a predetermined cylinder order, while the drive signal for the auxiliary fuel injection valve 7 is
Occurs every time the TDC signal occurs.

If the determination result in step 1 is negative (No) and the determination result in step 2 is positive (Yes)
When either of the cases holds true, ECU5
As described above, the main arithmetic and control circuit diagnoses that it has lost its normal function and activates the alarm device 19 to issue an alarm (step 5). Various aspects can be considered for this alarm device, and a warning light may be turned on.

Next, it is determined whether or not the starter switch 16b is in the on state (step 6). If the determination result is affirmative (Yes), that is, the starter switch 16b is turned on.
When the engine 6b is in the ON state and the engine is starting, the process proceeds to step 7, where the auxiliary circuit, which is a compensation circuit when the above-mentioned main arithmetic control circuit in the ECU 5 loses its normal function, controls the fuel supply amount at the time of engine starting. Do this. That is, the auxiliary control circuit supplies each injector with a drive signal that opens the main fuel injectors 6 and the auxiliary fuel injectors 7 of all cylinders simultaneously every time a TDC signal is generated from the TDC sensor 11 (b in FIG. 3). .
In this case, the same drive signal for opening the main fuel injection valve and the auxiliary fuel injection valve is used to simplify the configuration of the auxiliary control circuit, and the fuel injection time at this time is based on the following equation (3). is calculated.

T _OUT = K ₃ ×T _iFS (3) Here, T _iFS is a function of the engine water temperature signal from the engine water temperature sensor 10, and is at least a value necessary to ensure engine operation, and is a This value corresponds to approximately 1/4 of the fuel injection time of the main fuel injection valve when it is operating normally. or,
K ₃ is a constant value and is a coefficient set based on the on-off signal of the starter switch 16b. When the engine is started with the starter switch 16b in the on state, that is, in step 7, K ₃ is set to, for example, 1.0, and will be described later. After the engine is started with the starter switch 16b in the OFF state (step 8), it is set to a value smaller than 1, for example, a predetermined value in the range of 0.2 to 0.5.

The solid line in Figure 4 is the valve opening time T _iFS at engine start.
is given as a function of the engine water temperature Tw, and the broken line in the figure shows the valve opening time (K ₃ ×T _iFS ) after engine startup, which will be described later. In this way, the ECU 5 made the opening time of the main fuel injection valve 6 and the auxiliary fuel injection valve 7 at the time of engine startup a function of the engine water temperature.
Loss of normal function of the main arithmetic and control circuit, which will be described later, is thought to occur most frequently during cold starts, and engine water temperature is the dominant factor in the amount of fuel supplied during cold starts, and there are a number of factors. This is because the configuration of the auxiliary control circuit can be simplified as will be described later by limiting as much as possible.

Furthermore, as mentioned above, when starting the engine, both the main fuel injection valve and the auxiliary fuel injection valve are controlled to open by the same drive signal, so that the amount of injection that the main fuel injection valve 6 injects each time the TDC signal is generated is This is based on the fact that the amount of fuel required for the auxiliary combustion chamber is approximately equal to the amount of fuel required, and that the configuration of the auxiliary control circuit can be simplified by using the same drive signal. In addition, in order to simplify the configuration of the auxiliary control circuit, when using the same drive signal, the amount of fuel supplied to the main combustion chamber and the auxiliary combustion chamber is determined by the valve opening area of each injector, and the fuel supply to the injector. By properly designing the pressure, etc., it is possible to set the amount to an appropriate amount.

Next, if the determination result in step 6 is negative (No), that is, if the starter switch 16b is in the OFF state after starting the engine, the process proceeds to step 8. In step 8, the auxiliary control circuit in the ECU 5 outputs a drive signal for the main fuel injectors so as to simultaneously open the main fuel injectors of all cylinders every time the TDC signal is generated, as in step 7. As described above, the injection time T _OUT is set to the starting coefficient times (K ₃ ×T _iFS ). In this way, by simply multiplying the amount of fuel supplied to the main combustion chamber after engine startup by a factor of the initial amount, the configuration of the auxiliary control circuit can be simplified and engine operation at least at a medium load level can be ensured.

On the other hand, the amount of fuel supplied to the auxiliary combustion chamber after the engine starts is set to a constant amount, that is, the fuel injection time T _OUT of the auxiliary fuel injection valve is set to a constant value. This means that the amount of fuel required to be supplied to the auxiliary combustion chamber after the engine starts is not significantly affected by engine temperature, and if the amount of fuel supplied to the auxiliary combustion chamber is the same as that during normal medium-load operation, it will be sufficient over at least the entire operating range. This is because engine operation can be ensured and the configuration of the auxiliary control circuit can be simplified.

Note that T _iFS in equation (3) is not limited to being a function of the engine water temperature as described above, but may be set depending on a parameter value representing the intake air amount, for example.

FIG. 5 shows a circuit configuration within the ECU 5 according to the present invention. When the ignition switch 16a constituting the key switch 16 is closed, the power supply voltage of the battery 17 is supplied to the constant voltage power supply 501, and a constant voltage V _CC1 is generated on the output side of the constant voltage power supply 501.
This constant voltage V _CC1 is supplied as an overall control voltage within the ECU 5, and a portion thereof is supplied to the main arithmetic control circuit 503 as a power source, and also to the voltage drop detection circuit 502.

The main arithmetic control circuit 503 uses the above formula based on the various engine parameter signals such as the engine water temperature signal from the engine water temperature sensor 11 shown in FIG. The fuel injection times T _OUTM and T _OUTS in (1) and (2) are calculated, and the valve opening control signals for the main fuel injection valve 6 and sub-fuel injection valve 7 corresponding to the fuel injection times are calculated. Output.
The valve opening control signal for the main fuel injection valve 6 is generated intermittently for each injection valve of the main fuel injection valves 6a to 6d of each cylinder.
For each occurrence of the TDC signal, address one signal, e.g.
The AND circuit 506 corresponding to each main fuel injector is generated in the order corresponding to the third, fourth, and second main fuel injectors and is in an open state as described later.
a to 506d and OR circuits 507a to 507
d to each drive circuit 508a to 508d (a in FIG. 3). Each drive circuit 508 to 508d supplies a drive signal for opening the main fuel injection valve to the corresponding fuel injection valve 6a to 6d while the valve opening control signal is being input.

On the other hand, the valve opening control signal of the auxiliary fuel injection valve 7 is TDC
The AND circuit 517 and OR circuit are generated every time a signal is generated (a in FIG. 3) and are in an open state as described later.
It is supplied to a sub-drive circuit 520 via a circuit 519. The sub drive circuit 520 supplies a drive signal for opening the sub fuel injection valve 7 to the sub fuel injection valve 7 while the valve opening control signal is being input.

The voltage drop detection circuit 502 is connected to a constant voltage power supply 50.
When the voltage V _CC1 from 1 falls below the predetermined voltage (4.75V) at which the main arithmetic control circuit 503 loses its normal function, a high level = 1 is output, and the high level signal is sent to the main arithmetic control circuit 503. input to the circuit 503
1 through the OR circuit 509 to stop the operation of the alarm device 1.
Activate 9. The high level signal from the voltage drop detection circuit 502 is further ANDed via an OR circuit 509.
Circuits 511a to 511d and AND circuit 518
At the same time, the inverter 510 sets the low level to 0.
Then, the AND circuits 506a to 506d and the AND circuit 517 are respectively closed.

A watchdog timer 512 is connected to the main arithmetic control circuit 503. The watchdog timer 512 has a function of determining whether the control program executed by the main arithmetic control circuit 503 is being executed properly according to a predetermined procedure every time a TDC signal is generated. The watchdog timer 512 is activated by a watchdog timer activation signal outputted every time the main processing control circuit 503 executes a predetermined operation based on a predetermined control program. If there is no input within this range, the main arithmetic and control circuit 503 diagnoses that there is a runaway state, outputs a high level signal from the output side of the watchdog timer 512, and outputs a high level signal from the voltage drop detection circuit 502. In the same way as when outputting
6a to 506d and the AND circuit 517, and at the same time, the AND circuits 511a to 511d and
AND circuit 518 is opened.

Reference numeral 504 denotes an auxiliary control circuit, which, like the other parts except the main arithmetic control circuit, is configured to be operable at a voltage lower than the constant voltage V _CC1 , for example, 3V. The engine water temperature sensor 11 is connected to a non-inverting input terminal of a comparator 504h.
The pulse signal (sixth b) from the first one-shot circuit 505 is sent to the second one-shot circuit 504.
b. It is input to each reset terminal of the third one-shot circuit 504j, the first integrating circuit 504c, and the second integrating circuit 504d to reset each of them, and the second one-shot circuit 5 is inputted via the delay circuit 504a.
04b and the trigger input terminals of the third one-shot circuit 504j.

The second one-shot circuit 504b generates a pulse signal having a maximum time width corresponding to the assumed lowest engine water temperature shown in FIG. 4 (FIG. 6c). The pulse signal of the second one-shot circuit 504b is transmitted to the first integrating circuit 504c and the second integrating circuit 504b.
4d and respective circuits 504c and 504
d integrates this pulse signal as a time function. First integrating circuit 504c and second integrating circuit 50
Changes in the output value of 4d are shown by the solid and broken lines in Figure 6d, and these output characteristics can be set to any time function by configuring the integrator circuit with a circuit with an arbitrary time constant. I can do it. In the embodiment of FIG. 6d, the time constant of the second integrating circuit 504d is approximately 1/2 of the time constant of the first integrating circuit 504c, that is, the above equation
It is set to a value corresponding to the coefficient K ₃ in (3).

First integrating circuit 504c and second integrating circuit 504
The output signal of d is supplied to the inverting input terminal of the converter 504h through switches 504f and 540g, each of which is constituted by a field effect transistor (hereinafter simply referred to as "FET") in an open state. Whether the FETs 504f and 504g are open depends on whether the engine is being started or after it has been started. That is, the starter switch 16b constituting the key switch 16
is closed and the starter 18 is operating, that is, the engine is starting, the level correction circuit 513
outputs high level = 1, and this high level signal is inverted to low level by inverter 514 and FET5
04g is closed, and the high level signal which is inverted again by the inverter 504e is input to the gate terminal of the FET 504f, thereby opening the FET 504f. Therefore, it is in an open state while the engine is starting.
The output signal of the first integrating circuit 504c is supplied to the comparator 504h via the FET 504f.
After the starter switch 16b is opened and the engine is started, the output of the level correction circuit 513 is reversed to a low level, and contrary to the above, the FET 504f is closed.
FET504g is opened and the second integration circuit 504
The output signal of d is supplied to comparator 504h.

The comparator 504h outputs a high level signal=1 to the AND circuit 5 while the signal voltage supplied to its inverting input terminal is lower than the signal voltage from the engine coolant temperature sensor 11 supplied to its non-inverting input terminal.
04i (e in FIG. 6). The high level signal of the second one-shot circuit 504b is supplied to the other input terminal of the AND circuit 504i, and while a high level signal is input to the two input terminals of the AND circuit 504i, the AND circuit 504i is at a high level. Output signal = 1 (6th
Figure f). This high level signal is supplied to each drive circuit 508a to 508d via the AND circuits 511a to 511d in the open state, and all the main fuel injection valves 6a to 6d are simultaneously driven to open (the third Figure b). The lower the engine water temperature, the higher the internal resistance of the water temperature sensor 11, and therefore the higher the engine water temperature signal voltage supplied to the non-inverting input terminal of the comparator 504h, the higher the high level signal output from the AND circuit 504i. The time width of , that is, the main fuel injection time T _iFS in the equation (3) becomes longer.

When the engine starts, the high level signal from the inverter 504e that opens the FET 504f is
It is also input to the AND circuit 504l and the circuit 504l is
The high level signal outputted by the AND circuit 504i is passed through the AND circuit 504l and the OR circuit 504m, and is further in the open state.
The signal is supplied to the sub-drive circuit 520 via the AND circuit 518 and the OR circuit 519 to open the sub-fuel injection valve 7. In other words, when starting the engine, AND
The main fuel injection valves 6a to 6d and the auxiliary fuel injection valve 7 are simultaneously controlled to open by the same valve opening control signal outputted from the circuit 504i.

After the engine is started, the high level signal inverted by the inverter 514 is sent to the AND circuit 5.
04k is in an open state, and the AND circuit 504l is inverted by the inverter 504e.
to a closed state. The pulse signal (b in FIG. 6) of the first one-shot circuit 505 via the delay circuit 504a is transmitted to the third one-shot circuit 504j.
A pulse signal having a predetermined time width is generated every time a TDC signal is generated (g in FIG. 6). The pulse signal from this third one-shot circuit 504j is sent to the opened AND circuit 504k and OR circuit 504.
The fuel is further supplied to the sub drive circuit 520 via the AND circuit 518 and the OR circuit 519 to open the auxiliary fuel injection valve 7 for a certain period of time.

Incidentally, the voltage change on the output side e of the comparator 504h and the voltage change on the output side f of the AND circuit 504i after the engine starts are shown by broken lines in e and f of FIG. 6, respectively, and the time width of the output signal of the AND circuit 504i corresponds to K ₃ ×T _iFS in equation (3) above.

Furthermore, instead of the output signal from the engine coolant temperature sensor 11, a parameter signal representative of the intake air amount, such as a throttle valve opening signal, an intake pipe negative pressure signal, etc., is used at the non-inverting input terminal of the comparator 504h. Good too. That is, for the reasons mentioned above, it is desirable to use engine water temperature as a parameter to determine the amount of fuel supplied when starting the engine, but even during backup, it is desirable to supply a more appropriate amount of fuel, so it is used as a parameter that indicates the engine load. The amount of fuel supplied may be determined according to the amount of intake air. In this case, by configuring the first integrating circuit 504c and the second integrating circuit 504d to have characteristics that change depending on the output characteristics of the parameter sensor used, the required time width T _iFS can be obtained. You can.

Furthermore, when the main arithmetic and control circuit 503 loses its normal function, the amount of fuel supplied to the auxiliary combustion chamber after the engine starts is shown as an embodiment in which a constant value is supplied regardless of the engine water temperature. The amount of fuel supplied to the sub-combustion chamber may be set in accordance with a parameter value representing the amount of air.

As detailed above, according to the first invention, in the fuel supply control method for electronically controlling the amount of fuel supplied to a multi-cylinder internal combustion engine having a combustion chamber for each cylinder, the amount of fuel supplied to the combustion chamber is detecting a power supply voltage value of a main arithmetic control circuit that sequentially outputs a first control signal for controlling the fuel amount in accordance with a predetermined cylinder order;
Determining whether the voltage value has fallen below a predetermined value and whether a predetermined period of time has elapsed without the main arithmetic and control circuit performing a predetermined operation, and when either of these conditions is satisfied; , a second control signal outputted from the auxiliary control circuit is used as an alternative control signal in place of the first control signal outputted from the main arithmetic control circuit, and the alternative control signal is transmitted from the auxiliary control circuit to all cylinders. The control signals are simultaneously output to supply the combustion chamber of each cylinder with an amount of fuel according to the second control signal, and the amount of fuel supplied to the combustion chamber based on the second control signal is determined based on the engine temperature and intake air. Since the determination is made according to either one of the parameter values representing the amount, it is possible to ensure engine starting even if the power supply voltage drops, and at least the engine operation can be maintained even if the arithmetic control circuit goes into a so-called runaway state after the engine has started. can be continued.

Furthermore, the configuration of the auxiliary control circuit can be simplified by supplying fuel to each cylinder simultaneously, and more appropriate compensation control can be performed by the simpler auxiliary control circuit. can.

Furthermore, according to a second invention, in the fuel supply control method for electronically controlling the amount of fuel supplied to a multi-cylinder internal combustion engine having a main combustion chamber and a sub-combustion chamber for each cylinder, the main combustion chamber A first control signal for controlling the amount of fuel supplied to the auxiliary combustion chamber is outputted sequentially in accordance with a predetermined cylinder order, and a second control signal for controlling the amount of fuel supplied to the auxiliary combustion chamber is simultaneously output to all cylinders. Detects the power supply voltage value of the main arithmetic control circuit to output,
Determining whether the voltage value has fallen below a predetermined value and whether a predetermined period of time has elapsed without the main arithmetic and control circuit performing a predetermined operation, and when either of these conditions is satisfied; , third and fourth control signals output from the auxiliary control circuit are used as alternative control signals in place of the first and second control signals output from the main arithmetic control circuit, and these alternative control signals are is simultaneously output from the auxiliary control circuit to all the cylinders to supply fuel amounts corresponding to the third control signal and the fourth control signal to the main combustion chamber and the sub-combustion chamber of each cylinder, respectively, and The amount of fuel supplied to the main combustion chamber based on the third control signal is determined according to either one of the engine temperature and the parameter value representing the intake air amount, while the fourth
The amount of fuel supplied to the auxiliary combustion chamber based on the control signal is determined according to either the engine temperature or the parameter value representing the intake air amount, at least when starting the engine. Similarly to the first invention, for a multi-cylinder internal combustion engine equipped with both of the above, engine starting can be ensured even if the power supply voltage drops, and even if the arithmetic control circuit goes into a so-called runaway state after the engine has started, at least It is possible to continue engine operation, and, like the first invention, more appropriate compensation control can be performed by a simpler auxiliary control circuit.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a fuel supply control device to which the method of the present invention is applied, and Fig. 2 shows a control procedure for controlling fuel supply by an auxiliary control circuit when the main arithmetic control circuit loses its normal function. The flowchart shown in FIG. 3 is a diagram explaining the generation order of the valve opening control signals of the main fuel injection valve and the sub fuel injection valve, and Figure a shows the valve opening control of the main calculation control circuit. FIG. 4 is a diagram illustrating the relationship between the valve opening time of the fuel injection valve set in the auxiliary control circuit and the engine water temperature, and FIG. FIG. 5 is a circuit diagram showing an example of the internal configuration of an electronic control unit (ECU), and FIG. 6 is a diagram illustrating temporal changes in signal voltages generated at points a to g in the circuit of FIG. 1...Internal combustion engine, 5...Electronic control unit (ECU), 6, 6a, 6b, 6c, 6d
...Main fuel injection valve, 7...Auxiliary fuel injection valve, 11...
...Engine water temperature sensor, 12...Engine rotation speed (TDC) sensor, 16a...Ignition switch, 16b...Starter switch, 17...Battery, 502...Voltage drop detection circuit, 503...
...Main calculation control circuit, 504...Auxiliary control circuit, 5
12...Watchdog timer.

Claims (1)

[Scope of Claims] 1. In a fuel supply control method for electronically controlling the amount of fuel supplied to a multi-cylinder internal combustion engine having a combustion chamber for each cylinder, a first method for controlling the amount of fuel supplied to the combustion chamber; detecting a power supply voltage value of a main arithmetic and control circuit that sequentially outputs control signals according to a predetermined cylinder order, and determining whether or not the voltage value has become a predetermined value or less, and whether or not the main arithmetic and control circuit executes a predetermined operation. It is determined whether or not a predetermined period of time has elapsed without a state in which the operation is not performed, and when either of these conditions is satisfied, the control signal is output from the auxiliary control circuit in place of the first control signal output from the main arithmetic control circuit. A second control signal is used as an alternative control signal, and the alternative control signal is simultaneously output from an auxiliary control circuit to all cylinders to supply the combustion chamber of each cylinder with an amount of fuel according to the second control signal. and the amount of fuel supplied to the combustion chamber based on the second control signal is determined according to either one of a parameter value representing an engine temperature and an intake air amount. A fuel supply control method for an internal combustion engine. 2. In a fuel supply control method for electronically controlling the amount of fuel supplied to a multi-cylinder internal combustion engine having a main combustion chamber and a sub-combustion chamber for each cylinder, a first method for controlling the amount of fuel supplied to the main combustion chamber. a power supply voltage value of a main calculation control circuit that sequentially outputs a first control signal according to a predetermined cylinder order and simultaneously outputs a second control signal for controlling the amount of fuel supplied to the sub-combustion chamber to all cylinders; is detected, and it is determined whether the voltage value has fallen below a predetermined value and whether a predetermined period of time has elapsed without the main arithmetic and control circuit performing a predetermined operation, and one of these conditions is determined. is established, third and fourth control signals output from the auxiliary control circuit are used as alternative control signals in place of the first and second control signals output from the main arithmetic control circuit, and these alternative control signals are used as alternative control signals. The control signals are simultaneously output from the auxiliary control circuit to all cylinders, and are sent to the main combustion chamber and the sub-combustion chamber of each cylinder, respectively.
The amount of fuel is supplied according to the control signal and the fourth control signal, and the amount of fuel supplied to the main combustion chamber based on the third control signal is determined according to either one of the engine temperature and the parameter value representing the intake air amount. At the same time, the amount of fuel supplied to the auxiliary combustion chamber based on the fourth control signal is determined according to either one of the parameter values representing the engine temperature and the amount of intake air, at least when starting the engine. A fuel supply control method for a multi-cylinder internal combustion engine, characterized by: 3 Fuel is supplied to the main combustion chamber through a plurality of main fuel injection devices provided for each main combustion chamber, and one sub-fuel injection device provided for all sub-combustion chambers is supplied to the front-packed sub-combustion chamber. 3. A fuel supply control method for a multi-cylinder internal combustion engine according to claim 2, wherein the fuel is supplied through an injection device. 4. The main calculation control circuit sequentially outputs the first control signal in accordance with a predetermined cylinder order every time the predetermined rotational position signal of the engine occurs, and outputs the second control signal every time the predetermined rotational position signal occurs. The auxiliary control circuit outputs power to all cylinders simultaneously, and the auxiliary control circuit
The fuel for a multi-cylinder internal combustion engine according to claim 2 or 3, wherein the fourth control signal is simultaneously output to all cylinders every time the predetermined rotational position signal is generated. Supply control method. 5. The multi-cylinder internal combustion engine according to any one of claims 2 to 4, wherein the same control signal is used as the third control signal and the fourth control signal when starting the engine. Engine fuel supply control method. 6. The multi-cylinder internal combustion engine according to claim 2, wherein the amount of fuel supplied to the auxiliary combustion chamber based on the fourth control signal after engine startup is a constant amount regardless of engine temperature. Fuel supply control method.