JPS6048623B2 - Fuel stop device for electronically controlled fuel injection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel stop device for an electronically controlled fuel injection system having a function of stopping fuel during engine deceleration.

Conventionally, this type of device detects whether or not the opening of the throttle valve is below a set value by using a throttle sensor installed in the throttle valve of the engine to detect fuel stop during deceleration of the engine fuel, and detects whether or not the opening of the throttle valve is below a set value. This is carried out when the rotation speed of the engine is equal to or lower than the set value and the rotation speed of the engine is equal to or higher than the set value N2, and then fuel is supplied again from the fuel stop.Fuel return is performed when the throttle valve becomes equal to or higher than the set opening or the engine rotation speed. This is carried out when the engine speed is lower than the set engine speed No (hysteresis is provided to prevent engine hunting) which is lower than the fuel stop speed N2, but the engine speeds N2 and No change depending on the engine water temperature. Although it can be changed, it cannot be changed by the engine's falling speed, that is, deceleration.

For this reason, if the cooler is operating during engine racing, or if the engine is new and the engine load is large, the engine will stall if the return speed N2 is low. Despite the fact that fuel stop has many advantages such as improving fuel efficiency, reducing the emission of harmful exhaust gases, and reducing the heat load on the catalyst, it is necessary to lower the fuel return speed to prevent stalling during racing, which is not actually driving. This has the disadvantage that it is not possible to enlarge the fuel stop range, and as a result, the advantages brought about by the fuel stop cannot be fully exploited. The present invention has been made in view of the above-mentioned drawbacks, and it is possible to stop fuel injection when the engine decelerates by changing the value of the engine speed at the time of fuel injection return according to the degree of deceleration of the engine speed. In addition, in the case of normal deceleration operation, the engine speed value at the time of fuel injection return can be set sufficiently low to expand the range of fuel injection stop operation, further reducing fuel consumption and reducing exhaust emissions. It is an object of the present invention to provide a fuel stop device for an electronically controlled fuel injection device that can purify the fuel.

An embodiment of the present invention shown in the drawings will be described below.

FIG. 1 is a block diagram showing a calculation section of an electronically controlled fuel injection device according to the present invention. In Fig. 1, 1 is the primary side terminal of the ignition coil that detects the engine rotational speed signal in the form of a voltage waveform, 2 is a waveform shaping circuit that shapes the voltage waveform to prevent malfunctions, and 3 is the engine 1 in the case of a 6-cylinder engine. 1131) In a 1-circuit circuit for operating the electromagnetic injection valve 11 that injects fuel by rotation once, if the electromagnetic injection valve 11 is operated more than once per engine rotation, other frequency division ratios may be used. Of course, it is necessary. 4 is an arithmetic circuit which inputs a signal corresponding to the amount of intake air from the intake air amount meter 5 and divides the amount of intake air of the engine by the engine speed, that is, the amount of air sucked into one cylinder in one stroke. A pulse signal T, with a pulse time width Tp proportional to , is generated and output.

6 is a multiplication circuit which increases or multiplies the pulse time width Tp of the pulse signal T outputted from the arithmetic circuit 4 by various signals from the operating state detection means 7 for detecting engine water temperature, intake air temperature, etc. to produce a pulse. Pulse signal T with time width Tm.

It is something that creates 8 is a voltage correction circuit which inputs the pulse signal T2 from the multiplication circuit 6 and corrects a change in the fuel injection amount of the electromagnetic injection valve 11 due to the engine voltage. voltage correction pulse signal T.

It is something that creates 9 is an 0R circuit, and the arithmetic circuit 4,
Pulse signals T,, T2, T from the multiplication circuit 6 and the voltage correction circuit 8.

is input to generate a pulse signal T having a pulse time width (Tp+Tm+1tn), which is supplied to the output circuit 10, and the electromagnetic injection valve 11 is operated according to the pulse time width (Tp+Tm+1tn) of the pulse signal T.
+Tu) to supply the optimum amount of fuel into the engine according to the operating condition. Further, the multiplication circuit 6 outputs a pulse signal T when there is no increase in the amount of various types. is configured to have the same time and interval width as the pulse signal T, and the circuit is configured so that the amount of increase is proportional to the flowing current. 12 is a DA converter which converts the rotational speed signal from the frequency dividing circuit 3 into an analog voltage signal.

(In other words, if the rotation speed is high, the voltage is high, and if the rotation speed is low, the voltage is low. 13 is a comparator, and the voltage is low.
The output of No. 2 is led to one input of a comparator to determine whether the engine speed is above or below the set rotation speed. In this embodiment, the comparator 13 is configured to output an "O" level when the number of revolutions is above a set number of revolutions, and a level "1" when the number of revolutions is more than a set number of revolutions.
14 is a deceleration detection circuit that detects the speed at which the engine speed drops, that is, deceleration.If the engine speed drops by more than the set deceleration, it outputs a "1" level signal; if the engine speed drops by less than the set deceleration, it outputs a "1" level signal. It is configured to output an "o" level signal, and sets the fuel return rotation speed after fuel stop determined by the comparator 13 to a high value when the output of this detector 14 is at the "1" level, and outputs an "O" level signal. At level, control the value that gives the normal set rotation speed as much as possible.

A throttle sensor 15 detects the opening of the throttle valve, and outputs an "O" level signal only when the throttle valve opening of the engine is below a set opening.

Reference numeral 16 is an 0R gate, which operates only when the output of the throttle sensor 15 and the output of the comparator 13 are both at the "O" level.
” level signal, and this “o” level output blocks the output pulse signal T of the 0R circuit 9 from being supplied to the output circuit 10.

Next, the operation of the above embodiment will be explained using the electrical circuit diagram of the main part shown in FIG.

The rotational speed signal from the frequency dividing circuit is input to a known DA converter 12, converted into a voltage signal proportional to the engine rotational speed, and inputted to a comparator 13. This signal is input to the inverting terminal of the comparator Q via the resistor R of the comparator 13. On the other hand, the non-inverting terminal of the comparator Q is connected to resistors R2 and R3 that provide a reference voltage corresponding to the fuel stop rotation speed N. Here, when the voltage at the inverting terminal of the comparator Q becomes equal to or higher than the non-inverting terminal, that is, when the engine speed becomes equal to or higher than the fuel stop revolution speed N, the output of the comparator Q is reversed from the "1" level to the "O" level. , and during deceleration when the throttle valve is closed, the output of the throttle sensor 15 also goes to the "O" level, the pulse signal T for fuel injection from the OR circuit 9 is cut off, and the fuel is stopped. At the same time, when the output of comparator Q is inverted to the "O" level, resistor R. , a current flows through the diode D1, and the reference voltage at the inverting terminal of the comparator Q1 decreases. Therefore, when the engine speed decreases and fuel is restored (that is, re-injected from a stopped state), the fuel stop speed N is the lower engine speed N. Then, the output of the comparator Q is inverted to the "1" level. In other words, the fuel stop function has hysteresis. On the other hand, the deceleration detection circuit 14 for detecting the speed at which the rotational speed decreases is only 5.R.

,R,,R,,comparator Q. , capacitor C,,C
. ,C. , diode D2, inverter 14a, R-S
It is composed of a flip-flop 14b, and a D-A converter 12
The output of is passed through a delay element consisting of a capacitor C on one side and a resistor R5 on the other hand to a comparator Q. The other side is the resistor R. and R, and biased comparator Q. is input to the inverted terminal of Here, the engine speed drops at a deceleration greater than or equal to the set deceleration (the set deceleration can be arbitrarily set by the time constant of resistor R and capacitor C, and the bias potential of resistor R and R). Only when this happens, the level of the non-inverting terminal of the comparator Q2 having a delay element becomes lower than the level of the inverting terminal, and the output is inverted from the "1" level to the "O" level. This "O" level output of the comparator Q2 resets the known R-S flip-flop 14b via the trigger capacitor C3, and
The output Q of the -S flip-flop 14b becomes "1" level. On the other hand, the output of the comparator Q of the comparator 13 is input to the set input terminal S of the R-S flip-flop 14b via the inverter 14a) trigger capacitor C3, and the output of the comparator Q1 is set to the "1" level. The R-S" flip-flop 14b is set when the
When the output Q of the R-S flip-flop 14b is reversed from the "o" level to the "1" level, that is, when the deceleration of the engine rotation is greater than the set deceleration as during engine racing, the output Q of the R-S flip-flop 14b becomes "1". Level signal is diode D.

, is inputted to the non-inverting terminal of the comparator Q1 of the comparator 13 via the resistor R3, the potential of this non-inverting terminal increases and the fuel return rotational speed is N. This results in a higher set rotation speed N3. In the above embodiment, whether or not the engine is decelerating is determined based on the opening degree of the throttle valve.
Alternatively, it is also possible to adopt a configuration in which it is determined whether or not it is the time of deceleration based on the magnitude of the time width of the pulse signal for fuel injection of the OR circuit 9.

As described above, the fuel stop device of the present invention changes the value of the engine speed at the time of fuel injection return according to the degree of deceleration of the engine speed, thereby preventing engine stall due to stopping fuel injection during engine deceleration. In addition, in the case of normal deceleration operation, the engine speed value at the time of fuel injection return is set to a sufficiently low value, expanding the fuel injection stop operation range and maximizing the effect brought about by fuel stop. It is possible to withdraw as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an electrical circuit diagram of the main part of FIG. DESCRIPTION OF SYMBOLS 11... Electromagnetic injection valve, 13, 16... Comparator and 0R circuit which serve as determination means, 14... Deceleration detection circuit which serves as changing means, 16... Throttle sensor which serves as second means.

Claims (1)

[Claims] 1. In an electronically controlled fuel injection device configured to specify the amount of fuel supplied to the engine by an injection pulse signal applied to an electromagnetic injection valve, a first means for detecting the rotational speed of the engine and a deceleration state of the engine are provided. and a second means for detecting, and outputs of the first and second means are input, and a fuel injection stop signal is generated when the engine rotation speed is higher than the first set value and the engine is in a deceleration state. With,
determining means for generating a return signal for fuel injection when the engine speed decreases to at least a second set value; and an output from the first means to detect the degree of deceleration of the engine speed during engine deceleration. , the second set value in the determination means is set to a third set value different from the second set value in accordance with the degree of deceleration.
an electronically controlled fuel injection device, characterized in that the electronically controlled fuel injection device is configured to limit fuel injection operation to the engine in response to the stop signal and return signal from the determination device. fuel stop device.