JPH0263096B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel control device for a fuel-injected engine that stops fuel injection from a fuel injection valve when the engine decelerates.
This invention relates to an improvement in increasing the injection amount when returning to fuel injection from a stopped state of fuel injection.

(Prior Art) Conventionally, as a fuel control device for this type of engine, one disclosed in, for example, Japanese Unexamined Patent Publication No. 53-24925 has been known. As shown in Fig. 5A, when the engine operating state returns from the deceleration fuel cut region to the fuel injection region, the fuel injection valve is operated by widening the time width of the regular pulse (injection control signal) to the fuel injector. The amount of fuel injected from the injection valve is increased to prevent a decrease in output and the generation of unburned gas due to insufficient fuel upon return.

In addition, as shown in FIG. 2B, another method is known in which an extraordinary pulse is generated synchronously at the same time as the return and is inserted between regular pulses to increase the amount of fuel injection. .

(Problem to be Solved by the Invention) By the way, when the engine operating state returns from the deceleration fuel cut region to the fuel injection region, normally, as shown in FIG. There are two types: a return to the idle region, and a return to the fuel injection region (hereinafter referred to as acceleration region) excluding the idle region by accelerating again after deceleration.

However, in the above-mentioned conventional systems, the method of increasing the injection amount is uniform and fixed to generate an extraordinary pulse or widen the time width of a regular pulse, so that the difference between the idle region and the acceleration region is fixed. A drawback was discovered that it is difficult to control the increase in injection amount according to each region. In other words, when increasing the amount of fuel at the time of fuel recovery by widening the time width of the scheduled pulse, the air-fuel ratio can be controlled with high accuracy due to high precision injection control performance, and good idle stability can be ensured. It has been found that the response of the injection amount increase control is poor due to the control, and there is a drawback that good acceleration performance cannot be ensured at the time of returning to the acceleration region. On the other hand, in the case of increasing the amount of fuel at the time of fuel return using a temporary pulse, the increase control by generating the temporary pulse has good responsiveness and can ensure good acceleration performance at the point of return to the acceleration range, but on the other hand, the width of the temporary pulse is small. It is difficult to accurately control the air-fuel ratio in the idle region where control is required.
The drawback was that the idle state became unstable.

An object of the present invention is to perform injection amount increase control while ensuring good idling stability when returning from the deceleration fuel cut region to the idle region, and while ensuring good acceleration performance when returning to the acceleration region. be.

(Means for Solving the Problems) In order to achieve the above object, the configuration of the present invention, as shown in FIG. a deceleration detecting means 16 for detecting a deceleration, and an injection system that receives an operating state signal from the operating state detecting means 15 and outputs an injection control signal having a time width corresponding to the fuel injection amount according to the engine operating state to the fuel injection valve 9 at predetermined timings. A fuel for an engine comprising a control means 20 and an injection stop means 21 which receives a deceleration signal from the deceleration detection means 16 and prevents output of the injection control signal when the engine is decelerated and the engine operating state is within the deceleration fuel cut region. A control device is assumed. Temporary injection control signal output means 22 for outputting a temporary injection control signal to the fuel injection valve 9 and time width widening means 23 for widening the time width of the injection control signal are provided, and the engine operating state is reduced when the fuel is cut off. deceleration return detection means 18 for detecting return from the acceleration range to the idle range; and engine 1
receiving an acceleration detection means 17 for detecting acceleration of the acceleration detection means 17, a deceleration return signal from the acceleration return detection means 18, an acceleration signal and a non-acceleration signal from the acceleration detection means 17;
When the engine operating state returns from the deceleration fuel cut region to the acceleration region, the temporary injection control signal output means 22 is driven for a predetermined period of time immediately thereafter, and on the other hand, the engine operating state returns from the deceleration fuel cut region to the idle region. When this occurs, a control selection means 26 is provided which drives the time width widening means 23 for a predetermined time period immediately thereafter.

(Function) With the above configuration, in the present invention, when the fuel returns to the acceleration region, the injection amount is increased by outputting the temporary injection control signal, so the responsiveness of the injection amount increase control is improved, and a good result is achieved. Acceleration is ensured.

On the other hand, when the fuel returns to the idle region, the injection amount is increased by time width widening control, so the air-fuel ratio is appropriately controlled by the high precision injection control performance inherent in time width widening control, resulting in good idle stability. gender is ensured.

(Effects of the Invention) As explained above, according to the present invention, when the fuel returns to the acceleration region, the temporary injection control signal output means outputs the temporary injection control signal to the fuel injection valve, and the fuel returns to the idle region. At the time of recovery, fuel increase control is performed by time width widening control of the injection control signal by the time width widening means, so that fuel increase control at the time of fuel injection recovery is performed by
An engine fuel control device that can perform injection amount increase control while ensuring good acceleration performance in an acceleration region and idling stability in an idling region, and thus ensuring good engine operation characteristics. It is possible to provide

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 2 shows the overall configuration of a fuel control device for an engine according to the present invention, in which 1 is a fuel injection type engine, a cylinder 2 is formed in the engine 1, and a piston 3 is formed in the cylinder 2. The cylinder 2 is fitted so as to be movable up and down, and an intake port 5 and an intake port 6 communicate with a fuel chamber 4 formed above the cylinder 2 . An intake valve 7 is disposed at the opening of the intake port 5 to the combustion chamber 4, and the downstream end of an intake passage 8 is connected to the intake port 5. A fuel injection valve 9 for injecting fuel is provided. On the other hand, an exhaust valve 10 is disposed at the opening of the intake port 6 to the fuel chamber 4, and an exhaust passage 11 is connected to the intake port 6.

A throttle valve 12 for controlling the amount of intake air is disposed in the middle of the intake passage 8, and an air flow meter 13 for detecting the amount of intake air flowing through the intake passage 8 is disposed upstream of the throttle valve 12. ing. Reference numeral 14 denotes an engine rotation speed sensor for detecting the engine rotation speed, and the engine rotation speed sensor 14 and the air flow meter 13 constitute an operating state detection means 15 that detects the operating state of the engine 1. ing. Also,
Engine speed sensor 14 and throttle valve 1
2, the deceleration detection means 16 detects the deceleration of the engine, the acceleration detection means 17 detects the acceleration of the engine 1, and the deceleration detection means 17 detects that the engine operating state returns from the deceleration fuel cut region to the acceleration region or the idle region. It also constitutes a return detection means 18. The throttle opening signal of the throttle valve 12, the intake air amount signal of the air flow meter 13, and the engine speed signal of the engine speed sensor 14 are input to the control unit 19, respectively.

The control unit 19 has characteristics divided into three regions, a deceleration fuel cut region, an idle region, and an acceleration region determined according to the engine speed and throttle opening as shown in FIG. 3, into the control unit 19 in advance. The fuel injection valve 9 generates an injection control signal according to the engine operating state based on the flowchart shown in FIG.
The system is configured to control the operation of the fuel injection valve 9 so that the fuel injection valve 9 injects an amount of fuel according to the engine operating state by inputting the information to the fuel injection valve 9. That is, in the flowchart of FIG. 4 (S ₀ to S ₁₂ B indicate step numbers),
First, air flow meter 13 and rotation speed sensor 1
After detecting the actual intake air amount and actual engine speed based on each operating condition signal (intake air amount signal and engine rotational speed signal) in 4. Create a pulse as an injection control signal. Next, based on the engine speed signal from the engine speed sensor 14 and the throttle opening signal from the throttle valve 12, it is determined whether the engine operating state is in the deceleration fuel cut region shown in FIG. If YES, return to step _S1 , while
In the case of NO, which is not in the deceleration fuel cut region, it is then determined whether or not it is in the idle region. and,
If NO is not in the idle region, that is, if it is in the acceleration region, the engine rotation speed sensor 14
engine rotation speed signal and throttle opening signal of the throttle valve 12 (deceleration return signal of the deceleration return detection means 18 and acceleration signal of the acceleration detection means 17)
It is determined whether or not it is the moment of return to the acceleration region.If NO, the injection control signal (regular pulse) in step _S2 is waited for a predetermined time (for example, the TDC point of the crank angle) and fuel is injected. Valve 9
On the other hand, in the case _of YES, which is the instant of return, an extraordinary pulse as a temporary injection control signal is immediately outputted to the fuel injection valve 9 and the process returns to step _S1 , and after that, for a predetermined period of time (e.g. 0.05
seconds), the temporary pulse is synchronously outputted to the fuel injection valve 9 so as to be inserted between the regular pulses.

On the other hand, if the engine operating state is in the idle region (YES in step _S4 ), the engine speed signal of the engine speed sensor 14, the throttle opening signal of the throttle valve 12 (the deceleration return signal of the deceleration return detection means 18, and the Based on the non-acceleration signal of the acceleration detection means 17, it was further determined whether or not it was the moment of return to the idle area, and if YES, which was the moment of return, a timer time T was set (step
_S9 ) Later, the time width of the regular pulse in step _S2 is increased and corrected. . Then, this corrected periodic pulse is outputted to the fuel injection valve 9 after waiting for a predetermined time (for example, the TDC point of the crank angle), and the process returns to step _S1 . On the other hand, if NO is not the moment of return, it is determined whether or not the timer time T is zero, and if NO is not zero,
In this case, it is determined that the time is within the time width expansion control time, and after subtracting 1 from the timer time T (step
_S12 ), the time width correction of the regular pulse and the output of the corrected regular pulse are continued, and the process returns to step _S1 . On the other hand, if the timer time T is 0 (YES), it is determined that the time width widening control time has elapsed, and the regular pulse in step _S2 is outputted to the fuel injection valve 9 after waiting for a predetermined time, and the process is continued in step S2. Return to _S1 . Therefore, after creating a regular pulse according to the engine operating state in step _S2 , if the engine state is in the idle region and the timer time T immediately after returning to the idle region has elapsed (step _S4 ,
S ₈ , S ₁₁ ) and when the engine operating state is in the acceleration region and is not at the moment of return to the acceleration region (steps S ₄ , S ₅ ), a regular pulse is sent to the fuel injection valve 9 at predetermined intervals in step S ₆ . It constitutes an injection control means 20 configured to output an output to
If it is determined in _S3 that the engine operating state is in the deceleration fuel cut region, the process returns to step _S1 to stop the signals from step _S3 onwards and prevent the output of the regular pulse from the injection control means 20. This constitutes the injection stop means 21. Also,
In step _S7 , the temporary injection control signal output means 22 is configured to output the temporary pulse (temporary injection control signal) to the fuel injection valve 9, and in step _S10 , the period of the regular pulse (injection control signal) is output. It constitutes a time width widening means 23 which is designed to widen the width. Furthermore, when it is determined in step _S3 that the engine is not in the deceleration fuel cut region based on the deceleration return signal from the deceleration return detection means 18, the engine operating state is changed in step _S4 based on the acceleration signal from the acceleration detection means 17. If it is determined that the fuel is in the acceleration region and it is determined in step _S5 that it is the moment when the fuel returns, the process proceeds to step _S7 , where the temporary injection control signal output means 22 is driven for a predetermined period of time immediately thereafter. outputting the temporary pulse to the fuel injection valve 9 immediately and periodically;
On the other hand, if it is determined in step _S4 that the engine operating state is in the idle region based on the non-acceleration signal from the acceleration detecting means 17, and it is determined in step _S8 that it is the moment of fuel recovery, then the timer is T
The control selection means 2 proceeds to step _S10 and drives the time width widening means 23 until the period of time has elapsed to widen and correct the time width of the regular pulse.
6.

In FIG. 2, 24 is an air cleaner disposed at the upstream end of the intake passage 8, and 25 is a catalyst device disposed in the exhaust passage 11.

Therefore, in the above embodiment, the periodic pulse from the injection control means 20 (step S ₆ ) is maintained for a predetermined period of time (for example, 0.05 seconds) immediately after the engine state returns from the deceleration fuel cut region to the acceleration region. In addition, temporary injection control signal output means 22
Since the temporary pulse from (step _S7 ) is output to the fuel injection valve 9 so as to be inserted between the regular pulses, the amount of fuel injected from the fuel injection valve 9 is increased by that amount, and the fuel injection amount is insufficient. This prevents a decrease in output and the generation of unburned gas. At this time, since the increase in the fuel injection amount is performed by outputting a temporary pulse, the responsiveness of the increase in the injection amount is good, and good acceleration performance in the acceleration region can be ensured.

In addition, immediately after returning from the deceleration fuel cut region to the idle region until the timer time T elapses, a corrected regular pulse with an expanded time width is sent to the fuel injection valve 9 from the time width widening means 23 (step S ₁₀ ). Since the fuel is output, similarly to the above, by increasing the amount of fuel injected from the fuel injection valve 9, a decrease in engine output and generation of gas can be prevented. At this time, the increase in the fuel injection amount is performed by widening the time width of the regular pulse, so the air-fuel ratio can be controlled with high precision.
A stable idle state can be obtained.

In the above embodiment, the injection timing of the fuel injection valve 9 is determined based on the crank angle by inputting a regular pulse, but the intake air amount can also be detected by detecting the frequency of Karman vortices generated in the intake passage 8. The injection timing of the fuel injection valve 9 may be determined based on the intake air amount signal of the air flow sensor using the air flow sensor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of the present invention.
2 to 5 show embodiments of the present invention, FIG. 2 is a general schematic diagram, FIG. 3 is a characteristic diagram showing the deceleration fuel cut region, acceleration region, and idle region of the engine operating state, and FIG. The figure is a flowchart showing the control flow of the control unit, Figure 5A is an injection control signal waveform diagram during injection amount increase control by widening the time width, and Figure 5B is injection control signal waveform when injection amount increase control is performed by outputting a temporary pulse. It is a signal waveform diagram. 1...Engine, 9...Fuel injection valve, 12...
Throttle valve, 13...Air flow meter, 14
... Engine rotation speed sensor, 15 ... Operating state detection means, 16 ... Deceleration detection means, 17 ... Acceleration detection means, 18 ... Deceleration return detection means, 19 ... Control unit, 20 ... Injection control means, 2
1... Injection stop means, 22... Temporary injection control signal output means, 23... Time width widening means, 26... Control selection means.

Claims (1)

[Claims] 1 Operating state detection means for detecting the operating state of the engine, deceleration detection means for detecting deceleration of the engine, and a time width corresponding to the fuel injection amount according to the engine operating state upon receiving the operating state signal from the operating state detection means. injection control means for outputting an injection control signal to the fuel injection valve at predetermined intervals, and outputting the injection control signal when the engine is decelerated when the engine operating state is within a deceleration fuel cut region in response to the deceleration signal from the deceleration detection means. A fuel control device for an engine, comprising: an injection stop means for blocking the fuel injection valve; and a temporary injection control signal output means for outputting a temporary injection control signal to the fuel injector; and a time width for increasing the time width of the injection control signal. a deceleration return detection means for detecting that the engine operating state has returned from a deceleration fuel cut region to an acceleration region or an idle region; an acceleration detection means for detecting acceleration of the engine; and a deceleration return detection means for detecting acceleration of the engine. When the engine operating state returns from the deceleration fuel cut region to the acceleration region in response to the deceleration return signal from the acceleration detection means and the acceleration signal and non-acceleration signal from the acceleration detection means, the temporary injection control signal output means is activated for a predetermined period of time immediately thereafter. and control selection means for driving the time width widening means for a predetermined period of time immediately after the engine operating state returns from the deceleration fuel cut region to the idle region. Fuel control device.