JPH0734193Y2 - Electronically controlled fuel injection device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an electronically controlled fuel injection device for an internal combustion engine, which is equipped with a fuel injection valve in an engine intake system to inject fuel by electronic control, and is particularly synchronized with engine rotation. In addition to the predetermined fuel injection timing described above, the present invention relates to one having a function of interrupting fuel injection during acceleration.

<Prior Art> Conventionally, in an electronically controlled fuel injection device for an internal combustion engine, a fuel injection valve is provided in an engine intake system, and a normal amount of intake air at a predetermined timing synchronized with engine rotation is regulated. Separately from fuel injection, fuel is interrupted and injected under a predetermined acceleration condition, thereby improving acceleration performance (Japanese Patent Laid-Open No. 59-4.
See 9336 publication).

Specifically, the throttle valve opening is detected every predetermined time (for example, 10 ms), the change amount is calculated, and the change amount is compared with a predetermined value to determine acceleration / non-acceleration. At the time of the first determination from acceleration, the interrupt injection of the amount of fuel (see FIG. 4) according to the amount of change in the throttle valve opening is performed once.

<Problems to be solved by the invention> However, in such a conventional interrupt injection system, even when the driver accelerates by depressing the accelerator pedal at a constant speed, the acceleration start timing and the predetermined time interval There is a problem in that the interrupt injection amount is not constant due to a deviation from the detection timing of the throttle valve opening, which is performed in the above.

That is, as shown in FIG. 5, when the detection timing of the throttle valve opening for each predetermined time and the acceleration start timing are substantially the same, the degree of acceleration is taken into account at the next detection timing of the throttle valve opening. The change amount ΔTVO ₁ of the throttle valve opening is obtained, and the interrupt injection of the pulse width a is performed based on this, but as shown in FIG. 6, the acceleration start timing comes between the detection timings of the throttle valve opening. In this case, the change amount ΔTVO ₂ of the throttle valve opening, which does not correspond to the degree of acceleration, is captured, resulting in an interrupt injection with a small pulse width b based on this.

As a result, in the case of FIG. 6, the interrupt injection amount becomes insufficient, the air-fuel ratio becomes lean, and misfire occurs, causing a response delay in the rise of the indicated mean effective pressure, resulting in an accelerator ON shock. is there.

In view of such a conventional problem, the present invention can detect acceleration and perform interrupt injection with high responsiveness, and optimize an interrupt injection amount to improve drivability and the like. To aim.

<Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention comprises the following means (a) to (h).

(A) Throttle valve opening detection means for detecting the throttle valve opening of the engine at every predetermined time (b) Throttle valve opening for calculating the amount of change in the throttle valve opening detected by the throttle valve opening detection means Change amount calculation means (c) Acceleration determination means for determining acceleration / non-acceleration from the change amount of the throttle valve opening calculated by the throttle valve opening change amount calculation means (d) From non-acceleration by the acceleration determination means First interrupt injection amount calculation means for calculating a first interrupt injection amount based on the change amount of the throttle valve opening calculated by the throttle valve opening change amount calculation means when it is determined that the acceleration is the first time. ) First interrupt injection means for injecting the fuel of the first interrupt injection amount calculated by the first interrupt injection amount calculation means (f) Immediately after the interrupt injection by the first interrupt injection means A second interrupt for calculating a second interrupt injection amount based on the latest change amount of the throttle valve opening calculated by the throttle valve opening change amount calculating device when the speed judging device judges that the vehicle is accelerating again. Injection amount calculating means (g) Difference calculating means (h) for calculating the additional interrupt injection amount by subtracting the first interrupt injection amount from the second interrupt injection amount calculated by the second interrupt injection amount calculating means Second interruption injection means for injecting the additional interruption injection amount of fuel calculated by the difference calculation means <Operation> In the above configuration, the first interruption injection is performed when it is determined that the acceleration is the first acceleration from the non-acceleration. And immediately after that, when it is determined to accelerate again, the shortage in the first interrupt injection amount is additionally injected as the second interrupt injection to compensate,
It is possible to prevent shortage of fuel during acceleration and improve drivability.

<Example> An example of the present invention will be described below.

In FIG. 2, the engine 1 has an air cleaner 2 and an intake duct.
3, Air is taken in through the throttle chamber 4 and the intake manifold 5.

The throttle chamber 4 is provided with a throttle valve 6 that works in conjunction with an accelerator pedal (not shown) to control the intake air flow rate.

The intake manifold 5 or the intake port of the engine 1 is provided with a fuel injection valve 7 for each cylinder. This fuel injection valve 7
Is an electromagnetic fuel injection valve in which the solenoid is energized to open the valve, and the energization is stopped to close the valve.
A solenoid is energized by a drive pulse signal from the valve to open the valve, and fuel supplied from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator is injected and supplied to the engine 1.

Although this example is a so-called multi-point injection system, a single-point injection system in which a single fuel injection valve is provided in common to all cylinders upstream of the throttle valve or the like may be used.

The control unit 8 includes a microcomputer including a CPU, a ROM, a RAM, etc., receives input signals from various sensors, performs arithmetic processing as described below, and controls the operation of the fuel injection valve 7.

As the various sensors, a hot-wire type air flow meter 9 is provided in the intake duct 3 and outputs a signal according to the intake air flow rate Q which is the state quantity of the intake air.

Further, a crank angle sensor 10 is provided by being incorporated in a distributor (not shown), and the reference signal REF for each crank angle of 120 ° in the case of 6 cylinders and 180 ° in the case of 4 cylinders, and the crank angle of 1 °. Alternatively, it outputs the unit signal POS every 2 °. Here, the cycle of the reference signal REF, or
The engine speed N can be calculated by measuring the number of generated unit signals POS within a predetermined time.

Further, a potentiometer type throttle sensor 11 is provided on the throttle valve 6 and outputs a signal according to the throttle valve opening TVO.

A water temperature sensor 12 is provided in the water jacket of the engine 1 and outputs a signal according to the cooling water temperature Tw.

Further, the voltage of the battery 13 is applied to the control unit 8 via the engine key switch 14 as its operating power source and for detecting the power source voltage.

Here, the microcomputer incorporated in the control unit 8 calculates based on the intake air flow rate Q detected based on the signal from the air flow meter 9 and the signal from the crank angle sensor 10 according to a predetermined fuel injection control routine. The basic fuel injection amount Tp = K · Q / N (K is a constant) is calculated from the engine speed N and the cooling water temperature Tw is detected based on the signal from the water temperature sensor 12. The fuel injection amount Ti = Tp · COEF + Ts is calculated by correcting the correction coefficient COEF that is set and the voltage correction amount Ts that is set according to the voltage of the battery 13, and the pulse width corresponds to this Ti. The drive pulse signal is output to the fuel injection valves 7 of all the cylinders once per engine revolution at a predetermined timing to perform fuel injection.

On the other hand, the interrupt injection control routine shown in FIG. 3 is executed every predetermined time (for example, 10 ms), and thereby the interrupt injection is controlled.

Next, the interrupt injection control routine will be described with reference to FIG.

In step 1 (indicated as S1 in the figure, and so on)
The intake air flow rate Q detected based on the signal from the air flow meter 9, the engine speed N calculated based on the signal from the crank angle sensor 10, and the throttle valve opening detected based on the signal from the throttle sensor 11. TVO, water temperature sensor
The cooling water temperature Tw detected based on the signal from 12 is input.

In step 2, the basic fuel injection amount Tp = K · Q / N (K is a constant) is calculated based on the intake air flow rate Q and the engine speed N.

In step 3, the difference between the throttle valve opening TVO read this time and the previous throttle valve opening TVO _OL d is calculated to calculate the change amount ΔTVO = TVO−TVO _OL d of the throttle valve opening.

In step 4, TVO is substituted for TVO _OL d for the next calculation.

In step 5, the change amount ΔTVO of the throttle valve opening is compared with a predetermined value (equivalent to 1.6 ° / 30 ms), and when ΔTVO ≧ predetermined value, it is regarded as acceleration and the process proceeds to step 8. When ΔTVO <predetermined value, Considered as non-acceleration and proceed to step 6.

When it is determined that the vehicle is not accelerated, the I (counter) is set to 0 in step 6. Then, in step 7, the map is used to calculate the acceleration initial state correction coefficient TpACC from the basic fuel injection amount Tp.
To end this routine.

If it is determined to be accelerated, I is incremented by 1 in step 8. Therefore, I becomes 1 at the first acceleration from non-acceleration, and represents the number of times of acceleration determination that is incremented by 1 each time it is continuously determined as acceleration thereafter.

Next, in step 9, it is determined whether I is 1,
When I = 1 (acceleration first time from non-acceleration), step 10-
Go to 12.

In Step 10, the basic interrupt injection amount TRINJ0 is calculated from the change amount ΔTVO of the throttle valve opening and the cooling water temperature Tw according to the map.
To search.

In step 11, from the basic interrupt injection amount TRINJ0 and the acceleration initial state correction coefficient TpACC, the first interrupt injection amount TRINJ1 = T
Calculate RINJ0 / TpACC.

In step 12, a drive pulse signal having a pulse width corresponding to the first interrupt injection amount TRINJ1 is output to the fuel injection valves 7 of all cylinders to cause interrupt injection, and this routine is ended.

If I ≠ 1 in the determination in step 9, the process proceeds to step 13, and it is determined whether or not I is 2, and when I = 2 (when it is determined to accelerate again immediately after interrupt injection), Step
Proceed to 14-17.

In step 14, as in step 10, by the map,
The basic interrupt injection amount TRINJ0 is searched from the change amount ΔTVO of the throttle valve opening and the cooling water temperature Tw.

In step 15, the second interrupt injection amount TRINJ2 = T is calculated from the basic interrupt injection amount TRINJ0 and the acceleration initial state correction coefficient TpACC.
Calculate RINJ0 / TpACC.

In step 16, the first interrupt injection amount TRINJ1 is subtracted from the second interrupt injection amount TRINJ2 to obtain the additional interrupt injection amount TRIN.
Calculate J3 = TRINJ2-TRINJ1.

In step 17, a drive pulse signal having a pulse width corresponding to the additional interrupt injection amount TRINJ3 is output to the fuel injection valves 7 of all the cylinders to cause interrupt injection, and this routine ends.
However, it goes without saying that the injection is not performed when the additional interrupt injection amount TRINJ3 is a negative value.

If the determination in step 13 is I ≧ 3, this routine is finished as it is.

Here, step 1 corresponds to the throttle valve opening detection means together with the throttle sensor 11, step 3 corresponds to the throttle valve opening change amount calculation means, and steps 5, 9 and 13 correspond to the acceleration determination means. Steps 10 and 11 correspond to the first interruption injection amount calculation means, and step 12 corresponds to the first interruption injection means. Further, steps 14 and 15 correspond to the second interruption injection amount calculation means, step 16 corresponds to the difference calculation means, and step 17 corresponds to the second interruption injection means.

As a result, when it is determined that acceleration from non-acceleration is the first time, the first interrupt injection is performed, and immediately after that, when it is determined to be accelerated again, the amount of shortage in the first interrupt injection amount is added to the additional interrupt injection. Since the second interrupt injection as the amount is made up for, the lack of fuel during acceleration can be prevented and the drivability can be improved.

<Effect of Device> As described above, according to the present invention, in the interrupt injection system at the start of acceleration, the shortage of the first interrupt injection amount is supplemented by the second interrupt injection as the additional interrupt injection amount. It is possible to prevent a shortage of fuel during acceleration and improve drivability.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a system diagram showing an embodiment of the present invention, FIG. 3 is a flow chart showing the contents of arithmetic processing, and FIG. 4 is a throttle valve opening change amount. And FIG. 5 and FIG. 6 are views showing the conventional control characteristic diagram showing the relationship between the pulse width and the interrupt pulse width. 1 ... Engine, 7 ... Fuel injection valve, 8 ... Control unit, 9 ... Air flow meter, 10 ... Crank angle sensor, 11 ... Throttle sensor

Claims (1)

[Scope of utility model registration request] 1. An engine intake system is provided with a fuel injection valve for injecting fuel under a predetermined acceleration condition in addition to regular fuel injection of an amount corresponding to a state quantity of intake air at a predetermined timing synchronized with engine rotation. In an electronically controlled fuel injection device for an internal combustion engine that performs interrupt injection, a throttle valve opening detection means for detecting a throttle valve opening of the engine at every predetermined time, and a throttle valve opening detected by the throttle valve opening detection means. A throttle valve opening change amount calculating means for calculating a change amount; an acceleration determining means for determining acceleration / non-acceleration based on the change amount of the throttle valve opening amount calculated by the throttle valve opening change amount calculating means; The first interrupt injection based on the change amount of the throttle valve opening degree calculated by the throttle valve opening change amount calculating means when it is determined by the determination means that the acceleration is the first acceleration from non-acceleration. First interrupt injection amount calculation means for calculating the amount, first interrupt injection means for injecting the fuel of the first interrupt injection amount calculated by the first interrupt injection amount calculation means, and the first interrupt injection amount calculation means Immediately after the interrupt injection by the interrupt injection means, the second interrupt is performed based on the change amount of the throttle valve opening calculated most recently by the throttle valve opening change amount calculating means when the acceleration determining means determines that the acceleration is again performed. Second interrupt injection amount calculation means for calculating an injection amount, and an additional interrupt injection amount by subtracting the first interrupt injection amount from the second interrupt injection amount calculated by the second interrupt injection amount calculation means. An electronically controlled fuel injection device for an internal combustion engine, comprising: a difference calculating means for calculating; and a second interrupt injection means for injecting the additional interrupt injection amount of fuel calculated by the difference calculating means.