JPH03264744A - Fuel control device for engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption at deceleration or decelerated return by changing fuel cut return rotating speed at fuel cut and deceleration of an engine and fuel decreasing quantity at fuel return according to whether an anti-lock brake device functions or not. CONSTITUTION:When decelerating running condition of an engine is detected by a decelerating condition detecting means 101, fuel supplied from a fuel supply means 102 to the engine is cut by a fuel cut control means 103. Such fuel control device is provided with a judging means 104 for function of an anti-lock brake device to judge whether the anti-lock brake device functions or not. In case of a vehicle in which the anti-lock brake device does not function (the device is not mounted or troubled) compared with a vehicle in which the antilock brake device functions (a vehicle mounted with the device), the fuel cut control means 103 is limited by a fuel cut control limiting means 105.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel control device for an engine that cuts off the supply of fuel when the engine is decelerating.

(Prior art) Conventionally, when the throttle valve is fully closed and the engine speed is higher than a predetermined speed, it is determined that the engine is decelerating and the fuel supply from the injector is cut. Some are known that improve fuel efficiency. In addition, when deceleration is canceled, the amount of fuel supplied to the engine is returned to the normal fuel amount that is smaller than the normal fuel amount according to the driving condition at the time of cancellation of deceleration, and after that, the amount of supplied fuel is gradually reduced to the normal fuel amount. It is known that the number has been increased to .

These techniques are intended to improve fuel efficiency during deceleration, to prevent the occurrence of engine stalling by alleviating the sudden increase in the amount of fuel supplied due to recovery after deceleration is released, and to prevent engine stalling.

(Problem to be Solved by the Invention) By the way, in a car with a functioning anti-lock brake system, the engine speed decreases during panic braking because the deceleration of the wheels is smaller than in a car in which the above-mentioned system does not function. It has a low engine speed and has strong engine stall resistance.

Therefore, if the limit amount of fuel cut is set based on a car in which the anti-lock brake GA functions, there is a possibility that the engine speed will drop too much and cause the engine to stall in a car in which the anti-lock brake GA does not function.

On the other hand, if the fuel cut control amount was set based on a car in which the anti-lock brake system does not function, there was a problem that fuel efficiency would deteriorate in cars with the anti-lock brake system.

The present invention has been made with attention to these points,
The purpose of this is to improve fuel efficiency when decelerating or returning from deceleration, and to prevent engine stalling by appropriately changing fuel control during fuel cut depending on whether or not the anti-rotation and brake systems are functioning. It is to be.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the anti-lock brake device functions to adjust the fuel cut recovery rotation speed, fuel power, and fuel loss amount at the time of recovery from the fuel cut when the supplied fuel is cut. The setting should be made depending on whether or not.

Specifically, the solution taken by the present invention, as shown in FIG.
2, and a fuel cut control means 103 which receives the output of the deceleration state detection means and cants the fuel supply to the engine by the fuel supply means when the engine decelerates, while restoring the fuel supply when the deceleration release condition is established. The vehicle is equipped with an anti-lock brake system function determining means 104 for determining whether or not the anti-lock brake system is functioning, and the output of the determining means 104 is compared with a vehicle in which the anti-lock brake system is functioning. Vehicles in which the device does not function are configured to include fuel cut control limiting means 105 that limits the fuel cut control means.

It should be noted that the meaning that the anti-lock brake device is functioning refers to a state in which the above-mentioned device is installed, or a non-failure state in a car equipped with the above-mentioned device.

(Operation/Effect) With the above configuration, in the present invention, the fuel supply means is controlled by the fuel cut control means based on the engine deceleration state detected by the filtration speed state detection means, and fuel is supplied to the engine during engine deceleration. At the same time, the fuel cut control, which controls the restoration of fuel supply when deceleration is released, is compared with those in which the anti-lock brake system functions, and limits in which the anti-lock brake system does not function. For example, in the case of controlling the fuel cut return rotation speed, the rotation speed is compared with a case where the device does not function, and is set lower when the device is functioning.

As a result, it is possible to both improve fuel efficiency in a vehicle in which the above device functions and to prevent engine stalling in a vehicle in which the IT does not function.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an engine equipped with a fuel control device according to an embodiment of the invention. 1 is an engine, a cylinder 2 is formed in the engine 1, and a piston 3 is formed in the cylinder 2.
A combustion chamber 4 is formed by the cylinder 2 and the piston 3.

Further, 6 is an intake passage whose one end is connected to the combustion chamber 4 and the other end is open to the atmosphere via the air cleaner 7.
An intake valve 8 is provided at the opening of the intake passage 6 to the combustion chamber 4, and a fuel injector 10 is provided immediately upstream thereof as a fuel supply means for supplying fuel to the engine. . Further, the intake passage 6 is provided with a throttle valve 9 for adjusting the intake flow rate. Further, an ISC passage 11 is provided in the intake passage 6 so as to pass through the throttle valve 9, and the ISC passage 11 is provided with an ISCSC valve.

Furthermore, 15 is an exhaust passage whose one end is connected to the combustion chamber 4 and the other end is open to the atmosphere, and an exhaust knob 17 is provided at the opening of the exhaust passage 15 to the combustion chamber 4. . A catalyst 16 for purifying exhaust gas is disposed in the exhaust passage 15. In addition, 18 is a camshaft for driving the intake and exhaust valves 8 and 17, and 19 is a camshaft for driving the intake and exhaust valves 8 and 17.
is a distributor. The injector 10 and the SC valve 12 are connected to a control unit 30.
Its operation is controlled by

Further, 31 is an air flow sensor provided in the intake passage 6 upstream of the throttle valve to detect the intake air flow rate, 32 is an intake temperature sensor provided in the intake passage 6 upstream of the throttle valve to detect the intake air temperature, and 33 is a throttle A throttle sensor 34 is connected to the valve 9 to detect the opening of the throttle valve 9, a crank angle sensor 34 is provided on the camshaft 18 and is used to detect the crank angle, and 35 is a sensor provided in the cooling water passage of the engine 1 for cooling. A water temperature sensor for detecting the temperature of water; 36 is a 02 sensor provided in the exhaust passage 15 for detecting the oxygen concentration in exhaust gas; 37 is the presence or absence of an anti-lock brake system (hereinafter referred to as ABS);
This is an ABS determination unit that detects whether the ABS is malfunctioning or non-faulty. The outputs of these various sensors 31 to 37 are input to a control unit 30.

Next, the operation control of the control unit 30 will be explained based on the flow shown in FIG. 3.

After starting, first read the intake air amount Q in step S1, read the engine speed N in step S2,
In step S3, the basic injection pulse width Tp is calculated using K@Q/N. Here K is a constant. Furthermore, in step S4, operating conditions such as engine water temperature are detected, and step S1
．． In step S5, a correction coefficient C is calculated based on the operating state.

Next, the final injection pulse width TI is determined as “TI=TpXC+T
(Here, TV is the invalid injection time.) Next, in step S7, it is determined whether or not the vehicle is arriving at ABSH, and if it is arriving at ABSH, it is determined that the ABS is disabled in step S8. It is determined whether or not there is a failure, and if there is no failure, the process further proceeds to step S9.Step S
8, it is determined whether the engine rotation speed is greater than the fuel cant return rotation speed A, and if N>A, step S1 (+
It is determined whether the idle switch is on or off, and when it is on, it is determined that the engine is decelerating, and in step S, the deceleration flag ZFC is set to "O".

Then, in step S+2, the sampling injection pulse width TI is set to “O”.
”, and outputs this in step 513 to drive the injector 10, and returns to step SL.

On the other hand, if step S7 determines that the vehicle is not equipped with ABS, or step S8 determines that ABS is in a failure state, step 814 determines whether the engine speed N is greater than the fuel cut return speed B (A<B). If it is NIB, step S8. It is determined whether the idle switch is on or off, and when it is off, it is determined that the engine is decelerating, and the deceleration flag Zv is set in step see.
Set "0" to c. Then, in step S17, the final injection halus width TI is set to "O", and this is set in step S17.
13 to drive the injector 10 and return to step SI.

Also, in step S9, it is determined that the engine speed is N<A, or in step S10, it is determined that the idle switch is off, or in step S14, the engine speed N is N<B. It is determined that there is, or step S
When it is determined in step 15 that the idle switch is off, it is determined that the engine is not decelerating, and the process proceeds to step S.
At 18, set the deceleration flag ZFC to "1". Then,
The final injection pulse TI calculated in step s6 is executed, this is output in step S13 to drive the injector 10, and the process returns to step S1.

FIG. 3 is a time chart of the final injection pulse width TI of this embodiment, and as is clear from the figure, the time for four fuel cuts is longer when the vehicle arrives at ABSg compared to a vehicle without ABS.

Therefore, compared to a non-ABS-equipped vehicle, an ABS-equipped vehicle has a larger cut in the amount of fuel supplied, making it possible to prevent engine stalling in a non-ABS-equipped vehicle and improve fuel efficiency in an ABS-equipped vehicle.

As a 2.3 embodiment, control of fuel cut return fuel reduction, which temporarily reduces fuel when deceleration is released, will be described below.

FIG. 5 is a time chart showing the initial value of the fuel reduction after returning from the fuel cut, and FIG. 6 is a time chart showing the attenuation value of the fuel reduction after returning from the fuel cut. Compared to non-ABS equipped vehicles, ABS-equipped vehicles increase the initial value of the fuel cut return fuel reduction and reduce the attenuation value of the fuel cut return fuel reduction.
It is possible to prevent engine stalling in non-S-equipped vehicles and to prevent torque shock from occurring when deceleration is released in ABS-equipped vehicles.

In addition, the initial values and damping values of the fuel power, the return fuel loss, and the value of the resistor R1 and the capacitor C are input to the monomulti 18, as shown in Figure 3 of Japanese Patent Publication No. 58-20374. This can be changed by changing the value of tp.

Moreover, the following setting method can be considered as another example.

In other words, even if the vehicle body, engine, drive system (automatic transmission or manual transmission), etc. are exactly the same, the fuel cut control for both vehicles will differ depending on whether or not the vehicle is equipped with ABS. It is something.

In this case, fuel cut control is performed based on control parameters set in the engine control unit (actually fuel cut return rotation speed, etc.), so A
A unit for arriving at a BSa vehicle and a unit for vehicles not equipped with ABS are prepared, and control parameters are changed in advance between the two units.

In fact, on the car body assembly line, it is determined whether or not the ABSH has arrived (this can be done mentally or by the worker), and which of the above two control units should be installed. Determine the strength and install it. In this case as well, it is conceivable that the assembly robot determines and installs, or that the worker determines and installs. In short, this is a fuel cut control parameter setting method for two vehicles that differ only in whether or not ABS is installed.Step 1 is to determine whether ABS is installed, and step 2 is to determine whether ABS is installed. If not, select a control device whose fuel cut control parameters are set to more restrict fuel cut compared to the installed one, and as step 3, install the above control device. It is. It goes without saying that two types of control devices with different control parameters are available.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is an overall schematic configuration diagram, FIG. 3 is a flowchart of operation control of the control unit of the first embodiment, and FIG. The figure is a time chart of the fi final injection pulse width TI of the first embodiment, and Fig. 5.6 is a time chart of the final injection pulse width TI of another embodiment. 101...Deceleration state detection Means 102...Fuel supply means 103...Fuel cut control means 104...Anti-lock brake device determination means 105
...Fuel cut control restriction means

Claims (6)

[Claims] (1) A deceleration state detection means for detecting the deceleration state of the engine, a fuel supply means for supplying fuel to the engine, and receiving the output of the deceleration state detection means, and stopping the fuel from the fuel supply means when the engine decelerates. A fuel control device for an engine is provided with a fuel cut control means for controlling the anti-lock brake system. The invention is characterized by comprising fuel cut control limiting means that limits the fuel cut by the fuel cut control means when it is determined that the lock brake device does not function, compared to when it is determined that the anti-lock brake device functions. engine fuel control device. (2) The fuel cut control means receives the output of the deceleration state detection means and restores the fuel at a predetermined engine speed or less, and the fuel cut control limiting means increases the predetermined engine speed. Claim (1) characterized in that
Fuel control device for the engine described. (3) The fuel cut control means is for returning the fuel amount to a reduced amount than the normal fuel amount when the deceleration release condition is satisfied, and the fuel cut control limiting means is for reducing the initial value of the reduction. The fuel control device for an engine according to claim 1, characterized in that: (4) The fuel cut control means gradually increases the amount of supplied fuel to be returned to the normal fuel amount when the deceleration release condition is satisfied, and the fuel cut control limit means increases the rate of gradual increase. A fuel control device for an engine according to claim (1). (5) The engine fuel control system according to claim (1), wherein the anti-lock brake device function determining means determines whether or not the anti-lock brake device is installed. (6) The anti-lock brake device function determining means determines whether the anti-lock brake device is installed in a vehicle equipped with the anti-lock brake device;
2. The engine fuel control system according to claim 1, further comprising determining whether or not the anti-lock brake system is out of order.