JPS59101556A - Electronically controlled fuel injection device - Google Patents

Abstract

PURPOSE:To improve responsive performance of acceleration and optimize air-fuel ratio to be maintained, by performing an interruption of injection amount corresponding to the acceleration condition of a vehicle. CONSTITUTION:An injection amount arithmetic circuit 21 calculates an optimum fuel injection amount on the basis of an engine speed N and an intake air amount Qa. An acceleration detector circuit 24, on the basis of a change amount DELTATp of the basic injection pulse width, outputs a basic injection pulse signal Sp to a correction circuit 25 when a vehicle is not in an operating condition of acceleration without requiring interruption injection, while outputs an acceleration signal Salpha having a corresponding pulse width Talpha to an interruption injection circuit 26 when the vehicle is in the operating condition of acceleration with the interruption injection necessary. The interruption injection circuit 26, correcting the pulse width Talpha of the acceleration signal Salpha and calculating an optimum interruption injection amount on the basis of a signal from a water temperature sensor 27, outputs an interruption injection pulse signal Sow corresponding to a pulse width Tow to an injection pulse output circuit 29. An injector 30, being operated by the interruption injection pulse signal Sow or the final injection pulse signal So by the interruption injection pulse width Tow or the final injection pulse width To, injects fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically controlled fuel injection system, and more particularly, to an improvement in an electronically controlled fuel injection system in which acceleration increasing means for increasing the amount of fuel when both J and K cars are accelerated.

As a conventional electronically controlled fuel injection system, Nissan Motor Co., Ltd.
l Published June 1979 Technical Commentary WrE CC
The one described in ``SL series engine'' is known. This electronically controlled fuel injection device detects the operating state of the engine using various sensors, determines an appropriate injection amount using a control unit based on detection signals from the sensors, and The injector is operated by a control signal (injection pulse signal) from the injector. Control (-roll unino (- means ff1llff14) Injection amount calculation that determines the basic injection amount based on the engine rotational speed (based on crank angle sensor 1) and intake air amount (based on air flow meter 2) (not shown) circuit 11;
Cooling water temperature (based on water temperature sensor 3), exhaust oxygen concentration (0,
A correction circuit 12 determines various correction increases using sensors such as sensor 4 and corrects the basic injection amount, and an injection pulse signal with a pulse width corresponding to the corrected injection amount is sent to an injection timing signal (based on crank angle sensor 1). ) based on the injection pulse output circuit 13 that outputs an output to the injector 6 (for each engine rotation). Additionally, this control unit has an interrupt pulse calculation circuit 14, and this interrupt pulse calculation circuit 14 is activated when the idle contact of the throttle valve is turned OFF (when the throttle valve is no longer fully open). ), and outputs to the injection pulse output circuit 13 a signal obtained by increasing and correcting the basic injection amount according to the cooling water temperature.

However, in such a conventional electronically controlled fuel injection system, the amount of fuel increases when the vehicle accelerates only when the idle contact changes from ON to OFF (when the throttle valve is no longer fully closed). Since the interrupt injection (additional injection) was performed based on the interrupt injection pulse signal with the pulse width calculated by the injection pulse calculation circuit 14 according to the cooling water temperature,
When the vehicle is not accelerating when the throttle valve is in the idle position (fully closed), for example, when the throttle valve is further depressed after the idle contact is OFF, the control unit may not perform acceleration increase correction. There is a risk that the acceleration response performance of Acceleration increase correction may be performed even in a normal acceleration state), resulting in an excessive amount of fuel injection, which may cause misfire of the engine, resulting in deterioration of driving performance and an increase in emissions such as CO1HC.

This invention was made in view of these conventional problems, and it determines the acceleration state of the vehicle based on a sudden change in the pulse width of the injection pulse signal or a sudden increase in the amount of intake air, and determines the injection amount corresponding to the acceleration state. By performing interrupt injection, the optimum acceleration increase correction is made for the acceleration state throughout the engine's acceleration operation, improving acceleration response performance, and maintaining the optimum air-fuel ratio to prevent deterioration of driving performance and reduce exhaust composition. The purpose is to prevent deterioration.

The electronically controlled fuel injection device according to the present invention includes a sensor that detects the operating state of the engine and outputs a detection signal, and determines an injection amount adapted to the operating state based on the detection signal,
The fuel injection device includes an injector that injects fuel by operating a control unit that outputs an injection pulse signal with a pulse width corresponding to the injection amount. The control unit includes an injection amount calculation circuit that calculates an injection amount based on the engine rotation speed and intake air amount, and outputs an injection pulse signal with a pulse width corresponding to the injection amount, and a pulse width of the injection pulse signal. an acceleration detection circuit that determines the acceleration state of the vehicle by comparing the amount of change in the intake air amount or the amount of change in the intake air amount with a predetermined value, and outputs an acceleration signal corresponding to the acceleration state, and adapts to the acceleration state using the acceleration signal. an interrupt injection circuit that calculates the interrupt injection amount and outputs an interrupt injection pulse signal with a pulse width corresponding to the interrupt injection amount, and an output signal from the injection tftffl calculation circuit and the interrupt injection circuit. and an injection pulse output circuit that outputs an injection pulse signal to the injector.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

2 to 4 show an embodiment of an electronically controlled fuel injection device according to the present invention. FIG. 2 is a block diagram showing the control unit of the electronically controlled fuel injection system, and FIG. 3 is a flowchart of a program when signal processing is performed by a microcomputer (control unit) according to the present invention. In FIG. 2, 21 is an injection amount calculation circuit, and this injection amount calculation circuit 2
I determines the operating state of the engine based on the engine rotation speed N detected by a rotation speed sensor (for example, a rank angle sensor) 22 and the intake air amount Qa detected by an intake air amount sensor (for example, an air flow meter) 23. The optimal fuel injection interval (basic injection amount) is calculated. The injection amount calculation circuit 21 outputs a basic injection pulse signal sp having a basic injection pulse width "rp" corresponding to the basic injection amount to the acceleration detection circuit 24, and the acceleration detection circuit 24 outputs the basic injection pulse signal "sp" having a basic injection pulse width "rp" corresponding to the basic injection amount. T p
The driving state of the vehicle is determined based on the amount of change ΔTp in ζ. Then, this acceleration detection circuit 24 outputs the basic injection pulse signal SP to the correction time 1?825 when the vehicle is not in an accelerating driving state, and when interrupt injection is not required even if the vehicle is in an accelerating driving state. When the engine is in an accelerating operating state and requires interrupt injection, an acceleration signal Sα having a pulse width Tα corresponding to the accelerating operating state is output to the interrupt injection circuit 26. The correction circuit 25 includes a water temperature sensor 27 that detects the engine cooling water temperature and detects the oxygen concentration in the exhaust gas. The basic injection pulse width Tp of the dead wood injection pulse signal Sp is corrected based on signals from various sensors such as the second sensor 28, and a final injection pulse signal SO having a final injection pulse width TO is output to two injection pulse output circuits. On the other hand, the interrupt injection circuit 26 corrects the pulse width Tα of the acceleration signal Sα based on the signal from the water temperature sensor 27, calculates the optimal interrupt injection amount for the acceleration operation state at the cooling water temperature, and An interrupt injection pulse signal So- having a pulse width Tow with the injection fl D, tt Ji> is output to the injection pulse output circuit 29. When the injection pulse output circuit 29 receives the interruption injection pulse signal S, the injection pulse output circuit 29 immediately outputs the interruption injection pulse signal S.
OW is output to the injector 30, and when the final injection pulse signal SO is input, it is determined whether the input is a regular injection timing based on the signal from the crank angle sensor, and if it is not the regular injection timing, it is not output. First, the final injection pulse signal SO is output to the injector 30 only at the regular injection timing. Injector 3
0 operates by the interrupt injection pulse width To or the final injection pulse width TO to inject fuel when the interrupt injection pulse signal SO- or the final injection normal signal SO is input.

FIG. 3 is a flow chart showing the control J11 program of this electronically controlled fuel injection system, and this flow is executed, for example, at a predetermined time (10 m!I).

First, in the injection amount calculation circuit 21, the basic injection pulse width 1' is calculated based on the intake air amount Qa and the engine speed N.
I) is calculated as shown in the following equation.

The pulse signal Sp is input to the acceleration detection circuit 24 every Qms, and the acceleration detection circuit 24 first detects the previous basic injection pulse signal S every time the basic injection pulse signal sp is input.
It is determined whether the basic injection pulse width Tpo of po is larger than a predetermined value (5 ms).

Then, when T po > 5 ms, it is determined that the interrupt injection is not possible, and the current basic injection pulse signal lSp
is outputted to the correction circuit 25, and the correction circuit 25 applies a correction coefficient based on detection signals from various sensors (water temperature sensor 27.0□ sensor 28, etc.) to the basic injection Noculus width Tp of this basic injection pulse signal Sp. The optimum final injection pulse width TO for the engine is calculated by multiplying by . That is, the final injection pulse width TO is calculated according to the following equation.

To=Tp X (COEF) X (＾LPII＾)
+Ts Here, C0EF is water temperature increase correction, full-open increase and other correction coefficients, ALI')IA Hao□Sensor 2B (
D Correction coefficient for feed bank, Ts is injector 3
This is an insensitive pulse width of 0.

The final injection pulse signal SO having the final injection pulse width TO is manually inputted to the injection pulse output circuit 29, and the injection pulse output circuit 29 detects whether or not it is the normal injection timing after the engine has made one revolution from the crank angle sensor. Distinguish by the signal. If the injection timing is normal, the final injection pulse signal SO
is output to the injector 30 to generate the injector 30.The flow returns to the start without outputting the lune signal SO.

On the other hand, the acceleration detection circuit 24 detects that Tpo<5+++! When I, the pulse width 'T of the previous basic injection pulse signal Spo
'po and the pulse width of the current basic injection pulse signal Sp"r
It is determined whether the difference from p (ΔT p −1′ p −T po) is positive. Then, when ΔTp<O, it is determined that the engine is not in an accelerating operation state, and the basic injection pulse signal ゛p is output to the correction circuit 25, and the same program as described above is performed, and when Δ]''p>Q, Furthermore, it is determined whether the difference ΔTp is larger than a predetermined value (1 ms).When ΔTp≦1 ms, it is determined that although the acceleration operation is in progress, the acceleration is gradual and there is no need to perform interrupt injection. The basic injection pulse signal Sp is output to the correction circuit 25, and when ΔT p > l ms, the difference Δ1゛p,
That is, the acceleration pulse width Tα corresponding to the acceleration driving state is set. That is, ΔTp≦2+n5(ln+s<ΔT
p≦2m5), Tα-3ms, ΔTp≦3ms
When (2ms<ΔTp≦3m5), 'rα-611
13, T α-6 when Δ1' p > 3 ms
ms is set, and an acceleration signal Sα having this pulse width Tα
is output to the interrupt injection circuit 26. Based on the acceleration signal Sα and the cooling water temperature signal, the interruption injection circuit 26 generates an interruption injection pulse width To adapted to the acceleration state at the cooling water temperature.
Calculate w according to the following formula: T ow = T rx x
TWKF Here, TwKF is a correction coefficient based on the cooling water temperature. Then, the interrupt injection pulse signal So- having this interrupt injection pulse width Tow is input to the injection pulse output circuit 29,
When the injection pulse output circuit 29 receives the interruption injection pulse signal Sow, it immediately outputs an interruption injection pulse signal 5oiy to the injector 30. The injector 30 operates only during the period of the interrupt injection pulse width Tow to perform the interrupt injection.

FIGS. 4A to 4G show the regular injection and the interrupt injection in comparison with the conventional interrupt injection.

Now, considering the state where the throttle valve is fully closed and the accelerator is pressed to accelerate, the signal from the conventional throttle valve switch 7 changes from ON to OFF as shown in Fig. 4A.
Changes to F. If the change in the intake air amount Qa at this time is considered as shown in FIG. 4B, the basic injection pulse width TI) changes as shown in FIG. However, as shown in Fig. 4E, when conventional interrupt injection is not performed, the injection pulse signal is delayed by the maximum engine rotation amount until the injection pulse signal with a large pulse width is output after acceleration, and the torque is Including the intake and compression strokes, the maximum engine speed is delayed by 2 revolutions. Furthermore, the injection pulse signal when interrupt injection is performed by the signal of the conventional throttle valve switch 7 is as shown in FIG. The pulse width is the same as that of the signal. Therefore, it is not possible to obtain the interrupt injection amount corresponding to the acceleration state, resulting in failure to obtain sufficient torque, misfire, or deterioration of exhaust gas performance.However, in this embodiment, If so, as described above, the basic injection pulse width 1゛p changes in response to changes in the intake air amount Qa.
The pulse width of the interrupt injection pulse signal Sow is calculated based on the difference (change amount) Δ1゛p, and the interrupt injection pulse signal 3ow and the normal injection pulse signal SO are shown in FIG. It becomes as shown in G. That is, the amount of change Δ'rp in the basic injection pulse width 'rp is 1.4 ms and 2.6 ms.
ms, interrupt injection pulse signals Soyh<with pulse widths Tow of 3 ms and 6 ms are output. Therefore, it is possible to supply an amount of interrupt injection fuel corresponding to the acceleration state, and it is possible to optimize the air-fuel ratio during acceleration. As a result, sufficient torque can be obtained and exhaust gas performance can be improved. In addition, Fig. 4C shows the engine crank angle signal (1
80' signal).

FIG. 5 shows another embodiment of the invention.

In this embodiment, the acceleration driving state is detected based on the amount of change in the amount of intake air, and FIG. 5 shows a flowchart of the control program. In the description of FIG. 5, the same reference numerals Gkotsu 5z as those of the embodiment shown in FIGS. 2 to 4 will be used without explanation.

This program is executed at predetermined intervals (for example, every 10 m5), but first the intake air amount is read and the intake air amount signal Q1 is input. This intake air amount signal Qa is a signal inversely proportional to the intake air amount, and this intake air amount signal Q5
When inputted, it is compared with the previous intake air amount signal Q5o to determine whether the engine is in an accelerated driving state and the degree of acceleration. First, compare the current intake air amount signal Q5 with the previous intake air amount signal Q5o, and find that Q m > % - Q
, 10, the intake air meteor this time is R borrowed from the previous intake air flow rate, so there is no acceleration operation, or even if it is acceleration operation, it is a gradual acceleration and there is no need for interrupt injection. '+II cut. At this time, the basic injection pulse width 'Fp and the final injection pulse width TO are calculated by the following equation.

T p= , 1”o= ’rpX(:0E
Fx 8LPHA+T! a8 The subsequent program is the same as in the previous embodiment.

On the other hand, when Q:x<%Qio, the interrupt injection pulse width 'Fα is set according to the amount of change in the amount of intake air, that is, the degree of acceleration. Qa>! When 4Qao, Tcx=L ms, when Qa>%Q5o, Ttx-2111! l, Q 5 <'i4 Q
When 'ao', Tα-3m5 is set. Then, this interrupt injection pulse width Tα is corrected based on the cooling water temperature, and interrupt injection is performed in the same manner as in the embodiment described above.

Therefore, in this embodiment, the necessity of interrupt injection and its pulse width T are determined before calculating the basic injection pulse width Tp.
In order to calculate α, the time required to perform interrupt injection is the time required to calculate the basic injection pulse width Tp (for example, M
With C6802, it can be shortened by about 2 to 3 m5).

As explained above, according to the present invention, even if the engine is in any acceleration operating state, the optimum air-fuel ratio can be obtained for that state, and as a result, overall driving performance including acceleration response performance can be improved. At the same time, deterioration of the exhaust gas composition (increase in COlHC, etc.) can be prevented.

In addition, in the embodiment in which the acceleration state is classified according to the amount of change in the intake air amount, since the interrupt injection amount can be calculated simply by calculating the basic injection amount, it is possible to further improve the acceleration response performance. I can do it.

[Brief explanation of the drawing]

Fig. 1 shows a conventional electronically controlled fuel injection system in which the controller 1 to low unit 1 are shown in a block diagram, and Fig. 2 shows an embodiment of the electronically controlled fuel injection system of the present invention. The control unit is represented by a block diagram, and FIG. 3 shows a flowchart when signal processing is performed by the control unit. A graph shown in comparison thereto, FIG. 5, is a flowchart similar to FIG. 3 showing another embodiment of the present invention. 21--Injection amount calculation circuit, 24-Acceleration detection circuit, 26--Division injection circuit, 29- injection pulse output circuit, 22.23.27.28, ------- sensor, 30-
1 - Injector.

Claims (1)

[Claims] The operating condition of the engine is detected by the sensor 4", and the detection signal from the sensor is sent to the control unit 1.
- an electronically controlled fuel injection device in which the control unit determines an injection amount adapted to the operating condition and operates the injector with an injection pulse signal having a pulse width corresponding to the injection amount; an injection amount calculation circuit that calculates an injection amount based on the amount of intake air and outputs an injection pulse signal having a pulse width corresponding to the injection amount; and an amount of change in the pulse width of the injection pulse signal or the intake air. An acceleration detection circuit that determines the acceleration state of the vehicle by comparing the amount of change in the amount with a predetermined value and outputs an acceleration signal corresponding to the acceleration state, and an interrupt injection amount adapted to the acceleration state based on the acceleration signal. an interrupt injection circuit that calculates and outputs an interrupt injection pulse signal with a pulse width corresponding to the interrupt injection amount; An electronically controlled fuel injection device comprising: an injection pulse output circuit that outputs an injection pulse signal.