JPS62294736A - Fuel control device for engine - Google Patents

Abstract

PURPOSE:To prevent the generation of a recovery shock with no occurrence of an engine stop, by injecting fuel in a stroke except the intake stroke of an engine when it is recovered from a fuel cut in the deceleration time, when fuel is supplied in the time of an intake stroke. CONSTITUTION:An engine control unit 15 calculates a fuel injection amount from an injector 8 on the basis of detection values of air flow meter 5, crank angle sensor, throttle valve opening sensor 7, water temperature sensor 9, etc., and fuel is injected synchronously with the crank angle sensor when each cylinder is placed in an intake stroke. A throttle valve 6 is fully closed, further when an engine speed is in a predetermined value or more, a deceleration time fuel cut is performed, but when the engine speed decreases to a fuel cut engine speed or less, injection is restarted except in the intake stroke by 360 deg. advancing the ordinary injection timing.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention provides fuel supply during the intake stroke, and
The present invention relates to an engine fuel control device that stops fuel supply during deceleration.

(Prior Art) Conventionally, in order to improve ignition performance, it is known that fuel is supplied to an engine cylinder when it is in an intake stroke (see, for example, Japanese Patent Application Laid-Open No. 57-108428).

It is also known to stop the fuel supply during deceleration in order to improve fuel efficiency (for example, in Japanese Patent Publication No. 59-1173
(See Publication No. 6).

(The problem that the invention seeks to solve) Therefore, in an engine that supplies fuel during the intake stroke, it is conceivable to stop the fuel supply during deceleration. Since ignitability is good when fuel is injected during the stroke, there is a gap when recovery shock occurs due to rapid combustion.

As a countermeasure, reducing the fuel supply amount when the fuel supply is restored may be considered, but there is a problem in that the air-fuel ratio decreases and the engine stalls easily.

The present invention has been made in view of the above problems, and provides a fuel control device for an engine that supplies fuel during the intake stroke and stops the fuel supply during deceleration. The purpose is to prevent, rather than prevent,

(Means for Solving the Problems) The configuration of the present invention for achieving the above object will be explained based on FIG. 1 and FIG. 2 corresponding to the embodiment. an intake stroke detection means 101 for detecting the intake stroke, a fuel supply means 102 for receiving the output of the intake stroke detection means 101 and supplying fuel when the intake stroke is detected, and a deceleration detection means 103 for detecting the deceleration state of the engine. , and a fuel supply stop means 104 for stopping the fuel supply to the engine by the fuel supply means 102 when a deceleration state is detected in response to the output of the deceleration detection means 103. When the deceleration state is canceled in response to the output of the detection means 103, the fuel supply and timing correction means 105 restarts the fuel supply by the fuel supply means 102 and supplies the fuel in a stroke other than the rtit*i step. It is a haze characterized by being prepared.

(Function) When the fuel is restored after the deceleration state in which there is a risk of recovery shock is released, the fuel supply timing correction means 10
At step 5, fuel supply is restarted in a stroke other than the intake stroke. Therefore, vaporization and atomization are promoted, rapid combustion is suppressed, engine stall is prevented, and recovery shock is prevented from occurring.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an engine, to which an intake passage 2 and an exhaust passage 3 are connected. In the intake passage 2, an air cleaner 4, an air flow meter 5, a throttle valve 6, a throttle sensor 7 for detecting the opening degree of the throttle valve 6, and an injector 8 are arranged in this order from the upstream side. 9 is cooling water passage 1
This is a water temperature sensor located at 0.

Reference numeral 15 denotes an engine control unit, and fuel supply means 102 receives the output of an intake stroke detection means 101 (for example, a crank angle sensor) that detects that a cylinder of the engine is in an intake stroke, and supplies fuel when an intake stroke is detected. When the deceleration state is detected in response to the output of the deceleration detection means 103 that detects the deceleration state of the engine, the fuel supply means 102
and a fuel supply stop means 104 for stopping the fuel supply to the engine.

In addition, when the deceleration state is canceled in response to the output of the deceleration detecting means 103, the fuel supply means 102 restarts the fuel supply and the fuel supply timing correction means 105 performs the fuel supply in a stroke other than the intake stroke. Equipped with.

Next, the operation of the engine control unit 15 is shown in FIG. 3(a).
This will be explained using the flowchart in (b).

First, in FIG. 3(a), after the start, step S
Crank angle sensor (not shown), air flow meter 5. Each signal from the throttle sensor 7 and water temperature sensor 9 is read and each value is stored in registers T, Q, V, and W. Next, in step S8, it is determined whether or not it is time to start the engine. If this determination is YES and the engine is started, the process proceeds to step Ss, where a predetermined starting injection amount β is stored in the register, and in step S4, the register is A starting injection pulse is created based on the value, and is added to the injector 8 of the cylinder to be injected, which is determined according to the top dead center signal of the first cylinder, to perform starting injection, and the process returns to step S1 to perform the above-mentioned process. repeat.

When the engine starts, the process proceeds to step S based on a NO determination in step S, where the engine speed is calculated using the crank angle in register T and stored in register R, and then in registers R and Q. The basic fuel injection amount is calculated using the engine speed and the intake air amount, and is stored in the register I (step S).

Step S calculates the acceleration dV from the memory contents of register V.
/dt is determined, and it is determined whether or not this is thicker than the set value α, that is, whether or not it is during acceleration. This judgment is Y
If ES is accelerating, the set value β is stored as the acceleration correction amount in register C3 in step S. If the above judgment is NO and it is not accelerating, step S stores the acceleration correction amount in register C5. Set to 0. Here, the above set value β1
may be a constant value or may be a value that varies depending on the acceleration.

Also, step S1. is to compare the engine cooling water temperature in the register W1 with a set value W0, for example 60° C., to determine whether or not the engine is being warmed up. If the cooling water temperature is cold (NO) below the set value W, the temperature difference between the two (W, -W, ) is determined in step S11 to increase the fuel injection amount.
The temperature correction amount is obtained by multiplying the correction coefficient by and, and is stored in the register C1. On the other hand, the step S1. The judgment is Y
After the warm-up is completed in ES, the temperature correction amount in the register C1 is set to 0 in step S83.

Then, in step S13, the temperature correction amount in the register C1 and the acceleration correction amount in the register C6 are added to the basic fuel injection amount in the register to obtain the actual fuel injection amount, and the values are I0G, 10C. □ is stored in the register, and the injection angle θ is determined from the actual fuel injection amount in the register and stored in the register θ (step S, 4).

However, step S1. The intake stroke is detected using the crank angle in the register T, and the injection start timing is set to a predetermined value θ in the intake stroke. Injection angle θ in register θ corresponding to the calculated actual fuel injection amount
is added to calculate the injection end timing θ2, which is stored in the register θ, and fuel is injected during the intake stroke. .

In this way, when the injection start time θ1 and the injection end time θ2 are determined, the process waits in step SIT until the injection start time θ1 is reached, and when the injection start time θ1 is reached,
In step S I 1, a drive signal is applied to a predetermined injector 8 to start fuel injection, and while the injector 8 continues to be driven, fuel injection is performed while waiting in step S I 1, and when the injection end time θ is reached, step At Sma, the output of the drive signal is stopped, fuel injection is ended, and fuel injection for the next cylinder is performed.

Moreover, the injection timing of fuel injection is performed according to the flowchart shown in FIG. 3(b). That is, various signals are read from the engine speed sensor, idle switch, clutch/neutral switch, etc. (step S
, , ), based on these signals, it is sequentially determined whether the engine is in the idle state, whether the clutch is in the neutral position, or whether the rotation speed is equal to or higher than the cut speed (step S I M I
S M 31 S l 4).

However, during deceleration when the throttle valve 6 is in a fully open idle state and the clutch is not in the neutral position,
If the engine speed is at least the cut speed at which engine stalling does not occur even if the fuel is cut, all the deceleration fuel cut conditions are satisfied, so the injector 8 is controlled to execute the deceleration fuel cut (step S). , Then, a correction calculation is performed to advance the normal injection timing by 360 degrees (step S, @).

Also, if it is not idle, it is not decelerating, and
Even in the idling state, if the engine is in the neutral position, the engine is likely to stall, so fuel injection is performed at the normal injection timing (step S, . . . ).

Furthermore, even when decelerating in an idling state and not in a neutral position, if the rotation speed is below the cutoff speed, it is necessary to restore fuel to prevent engine stalling, and it is necessary to determine whether or not a fuel cut was performed last time. Do (Step S1.)
.

Then, if the fuel was cut last time, in order to prevent recovery shock, the injection is executed at the injection timing calculated in step S I m (step S, ),
Injected during a stroke other than the intake stroke.

Note that the fuel is injected by reading the ignition signal.

Therefore, for example, when looking at the first cylinder.

The fuel is injected by the ignition signal of the fourth cylinder. By doing so, the intake stroke is completed and the fuel can be injected at the beginning of the compression stroke, and the vaporization atomization time can be lengthened to prevent rapid combustion.

On the other hand, if there was no fuel cut last time, there is no risk of recovery shock, so injection is performed at the normal injection timing (steps S, , L).

Therefore, it will be injected during the intake stroke.

(Effects of the Invention) As described above, the present invention injects fuel in a stroke other than the intake stroke when returning fuel.
This results in rapid combustion and prevents recovery shock without causing an engine stall.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall configuration diagram of an engine fuel control device, FIG. 2 is a block diagram of an engine control unit, and FIGS. 3(a) and 3(b) are an engine control unit. 3 is a flowchart showing the flow of processing. 1...Engine, 2...Intake passage, 5
...Air meter, 7...Throttle sensor, 8...Injector, 15...
... Engine control unit, 101 ... Intake stroke detection means, 102 ... Fuel supply means, 1o
3...Deceleration detection means, 104...Fuel supply stop means. Figure 1 Ryo Figure 2 Figure 3

Claims (1)

[Claims] (1) An intake stroke detection means for detecting that a cylinder of the engine is in the intake stroke, a fuel supply means for receiving the output of the intake stroke detection means and supplying fuel when the intake stroke is detected, and deceleration of the engine. deceleration detection means for detecting the state;
and a fuel supply stop means for stopping fuel supply to the engine by the fuel supply means when a deceleration state is detected in response to the output of the deceleration detection means, wherein the deceleration state is canceled in response to the output of the deceleration detection means. 1. A fuel control device for an engine, comprising: a fuel supply timing correcting means for restarting the fuel supply by the fuel supply means and supplying the fuel in a stroke other than the intake stroke when