JP2627791B2 - Fuel supply system for multi-cylinder internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel supply device for a multi-cylinder internal combustion engine.

<Related Art> The following is a conventional example of a fuel supply device for a multi-cylinder internal combustion engine. That is, a basic injection amount T _P (= K · Q / N: K is a constant) is calculated from the intake air flow rate Q detected by an air flow meter or the like and the engine speed N, and various correction coefficients mainly corresponding to the water temperature. COEF, air-fuel ratio feedback correction coefficient α, and correction coefficient based on battery voltage
After calculating T _S , the fuel injection amount T _i (= T _P × COEF × α +
T _s ).

Then, synchronized with the reference signal from the crank angle sensor, the fuel output by the engine of the injection pulse signal of a pulse width corresponding to the fuel injection amount T _i from the control unit comprising a microcomputer or the like to the fuel injection valves Supply.

Specifically, the control device includes:
A reference signal is input at the same number as the number of cylinders and at every predetermined crank angle (for example, at every 180 ° crank angle in a four-cylinder internal combustion engine). Here, for example, the pulse width of the reference signal corresponding to the # 1 cylinder is formed longer than the pulse width of the reference signal corresponding to the other cylinder.

When the reference signal for cylinder discrimination is input, the cylinder is determined to be # 1 cylinder, and thereafter, for each input of each reference signal, the cylinder to be injected in accordance with a preset injection order (similar to the ignition order). Is determined.

Then, for each input of each reference signal, and sets the injection start timing based on the injection quantity T _i as the injection end timing and the combined intake stroke and the timing is always substantially constant crank angle position. Then, at the timing of the set injection start timing based on the position signal (for example, every 1 ° in crank angle) or the count value of the timer from the input of each reference signal, each fuel injection valve is operated once for two revolutions of the engine. They are operated individually at a ratio.

<Problems to be Solved by the Invention> However, in such a conventional fuel supply device, if the output system of the position signal fails due to an instantaneous interruption, the fuel injection control cannot be performed even if the output system of the reference signal is normal. There was a problem of becoming.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a fuel supply device for a multi-cylinder internal combustion engine that can continue fuel supply even when an abnormality occurs in a reference signal or a position signal.

<Means for Solving the Problems> For this reason, according to the present invention, as shown in FIG. 1, as shown in FIG. 1, a fuel injection valve A provided for each cylinder is inputted at every predetermined crank angle. Sequential control means for individually injecting at least once every two revolutions of the engine in accordance with a predetermined injection order at least in a predetermined operation region based on a reference signal and a position signal input at every crank angle smaller than the reference signal. B; counting means F for counting the number of input position signals in a predetermined input section of the reference signal; determining means G for determining whether the count number of the position signals is within an allowable range; When it is determined that the number is out of the allowable range, all of the fuel injection valves A are simultaneously synchronized in synchronization with the generation of the reference signal. And a simultaneous injection control means H for performing an injection operation.

<Operation> As described above, in the first aspect, when the number of input position signals is out of the allowable range, it is determined that an instantaneous interruption has occurred in the position signal, and all cylinders are simultaneously synchronized in synchronization with the generation of the reference signal. Perform injection control.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. In this embodiment, a four-cylinder internal combustion engine will be described.

In FIG. 2, air is sucked into the engine 1 through an air cleaner 2, an intake duct 3, a throttle chamber 4, and an intake manifold 5.

An air flow meter 6 is provided in the intake duct 3 and detects an intake air flow rate. The throttle chamber 4 is provided with a throttle valve 7 that works in conjunction with an accelerator pedal (not shown) to control the intake air flow rate. The intake manifold 5 is provided with an electromagnetic fuel injection valve 8 for each cylinder, and injects fuel supplied from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator to the engine 1.

The control of the fuel injection amount is calculated by a control device 14 including a microcomputer or the like described later based on an intake air amount Q detected by the air flow meter 6 and a signal from a crank angle sensor 9 built in the distributor 12 described later. The basic injection amount T _P = K ·
Calculate Q / N (K is a constant) and correct this accordingly to set the fuel injection amount T _i = T _P .COEF + T _S (COEF is a various correction coefficient, T _S is a voltage correction), A drive pulse signal having a pulse width is supplied to the fuel injection valve 8 at a predetermined timing in synchronization with the output signal of the crank angle sensor 9.

Each cylinder of the engine 1 is provided with an ignition plug 10 to which a high voltage generated by an ignition coil 11 is sequentially applied via a distributor 12, thereby igniting a spark and igniting and mixing an air-fuel mixture. Here, the timing at which the ignition coil 11 generates a high voltage is controlled via a power transistor 11a attached thereto. Therefore, the control of the ignition timing is performed by controlling the ON / OFF timing of the power transistor 11a with the ignition signal from the control device 14.

For this ignition timing setting as a parameter of the engine operating condition, the engine speed N calculated on the basis of a signal from the crank angle sensor 9, the basic injection quantity T _P which is calculated as described above is used .

The crank angle sensor 9 includes a signal disk plate 91 that rotates integrally with the distributor shaft 12a.
The signal disc plate 91 has 360 slits 93 for position signals (1 ° signal) and four slits for reference signals (180 ° signal) in the case of four cylinders. 94 are formed, and one of the four reference signal slits 94 is used for discriminating the No. 1 cylinder by changing the slit width. Then, the photoelectric detector 92 detects these slits 93 and 94 and outputs a position signal (360 per rotation of the distributor shaft 12a).
No.1 with 720 position signals from 93 slits)
A reference signal including a cylinder discrimination signal is output to the control device 14. The engine speed N can be calculated as the reciprocal of the cycle of the reference signal.

Further, a detection signal from the knocking sensor 13 is input to the control device 14.

The control device 14 counts the number of input position signals during a period (180 ° in crank angle) from when a reference signal is input to when a next reference signal is input.

Here, the control device 14 constitutes sequential control means, cycle measurement means, comparison means, counting means, determination means, and simultaneous injection control means.

Next, the operation will be described with reference to the flowchart of FIG. The routine shown in the flowchart of FIG. 3 is executed every time a reference signal is input.

First, the normal fuel injection control will be described. The detected intake air flow rate from the air flow meter 6 and the crank angle sensor 9
After calculating a basic injection amount T _P (= K · Q / N: K is a constant) based on a reference signal (engine speed N) from the controller, various correction coefficients COEF and air-fuel ratio feedback mainly depending on the water temperature Correction coefficient α and correction coefficient based on battery voltage
Based on T _S , the fuel injection amount T _i (= T _P × α × COEF + T _S )
Is calculated.

Then, by counting the number of inputs of the position signal from the time reference signal input, when its count value becomes the time set fuel injection, the fuel injection valve 8 is operated on the basis of the fuel injection quantity T _i. In this manner, the fuel injection valves 8 of each cylinder are individually operated at a rate of one for every two revolutions of the engine by sequential control according to a preset injection order.

During this control, the following routine is executed.

That is, in S1, the input cycle T from the time when the previous reference signal is input to the time when the current reference signal is input is set.
After measuring _REFN , the process proceeds to S2.

In S2, the input period of the current input period T _REFN the previous T _REFO
Is determined to be greater than or equal to a predetermined value. If YES, it is determined that the output system of the reference signal is momentarily interrupted. If NO, the process proceeds to S4 without passing through S3.

In S3, the occurrence of instantaneous interruption of the reference signal is flagged.
The value is stored as 0 in the memory, and the process proceeds to S4. Here, flag = 0 indicates simultaneous injection control.

In S4, the current input cycle T _{REFN is changed} to the previous input cycle T _REFO
Is stored in the memory for the next routine, and the process proceeds to S5.

In S5, the input number N of the position signal counted by the timer in the input section of the previous and current reference signals is read, and the flow proceeds to S6.

In S6, the input number N of the read position signal is 180
It is determined whether the number is equal to or not. If YES, it is determined that the output system of the position signal is normal, and the process proceeds to S8 without passing through S7. If NO, it is determined that a failure has occurred in the output system, and the process proceeds to S7.

In S7, the occurrence of instantaneous interruption of the position signal is flag = 0
As a memory.

In S8, it is determined whether or not a reference signal for cylinder determination has been input. If YES, the process proceeds to S9, and if NO, the routine is terminated.

At S9, the flag = 1 is stored in the memory. Here, flag = 1 indicates sequential control.

When the flag = 0, after performing the interrupt injection control of the fuel injection valves 8 of all the cylinders simultaneously in synchronization with the reference signal input immediately after the instantaneous interruption, the reference signal for the next cylinder determination is input. Until the flag becomes 1, the fuel injection valves 8 of all cylinders are subjected to simultaneous injection control once per one revolution of the engine in synchronization with the reference signal.

As described above, when the current input cycle T _REFN is longer than the previous input cycle T _FEFO by a predetermined value or more or when the number N of position signal inputs is not 180, after performing the interrupt injection, Simultaneous injection control is performed once per two engine revolutions until the next cylinder discrimination can be performed. Therefore, even if an instantaneous interruption occurs in the reference signal or the position signal, it is possible to suppress a decrease in the wall flow fuel amount. In addition, lean air-fuel ratio can be suppressed, and engine stall can be prevented. As another embodiment of the present invention, the fail safe at the momentary interruption of the reference signal may be omitted.

<Effect of the Invention> As described above, according to the present invention, when the number of input position signals is out of the allowable range, the simultaneous injection control is performed on the fuel injection valves of all cylinders in synchronization with the generation of the reference signal. Therefore, even if a momentary interruption of the position signal occurs, the leaning of the air-fuel ratio can be suppressed, and the occurrence of engine stall can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 1 ... engine, 8 ... fuel injection valve, 9 ... crank angle sensor, 14 ... control device

Claims (1)

(57) [Claims] A fuel injection valve provided for each cylinder is operated at least in a predetermined operating region based on a reference signal input at a predetermined crank angle and a position signal input at a crank angle smaller than the reference signal. In a fuel supply device for a multi-cylinder internal combustion engine, comprising: a sequential control means for individually performing an injection operation once every two rotations of the engine in accordance with a predetermined injection order, the number of input position signals in a predetermined input section of the reference signal Counting means for counting the position signal; determining means for determining whether or not the count number of the position signal is within an allowable range; and when it is determined that the count number is out of the allowable range, all of the fuel injection valves are referred to as a reference signal. Simultaneous injection control means for simultaneously performing an injection operation in synchronization with the generation. Fuel supply device for a cylinder internal combustion engine.