JPS6035139A - Method for control of air-fuel ratio in electronically controlled fuel supply device - Google Patents

Abstract

PURPOSE:To enhance the comfort in driving a car and the rate of fuel consumption during acceleration by changing the air-fuel ratio according to to a time function on the basis of the size of change of the air-fuel raio, in case the air- fuel ratio is to be altered to a value determined by the subsequent condition, and thereby changing the air-fuel ratio gradually. CONSTITUTION:If stamping-in of the accelerator pedal 20 etc. causes transfer into No.2 operating condition, when the engine has been in No.1 operating condition, a computer 28 reads first the No.1 air-fuel ratio A/F1 for No.1 operating condition, and then No.2 air-fuel ratio A/F2 for No.2 condition after said transfer is calculated and set. Then the two ratios are compared, and a fuel injection device 18 and a throttle valve 14 are controlled so that A/F=f(A/F2-A/F1, t). Thus the air-fuel ratio A/F is altered. According to this arrangement the air-fuel ratio A/F changes from A/F1 gradually with a certain time lag to attain A/F2 at the time t2', so that the comfort in driving the car and the rate of fuel consumption are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electronically controlled fuel system configured to control the air-fuel ratio by controlling the air flow rate to be supplied to the engine based on various engine information using an actuator operated by a computer. The present invention relates to an air-fuel ratio control method in a supply device.

As a conventional electronically controlled fuel supply device, for example, Japanese Patent Application Laid-Open No. 57-9
A fuel priority type electronically controlled fuel supply device is known according to Japanese Patent No. 1343, and this is explained with reference to FIG.
1o is an engine, 12 is a throttle valve, 14 is an actuator of the throttle valve, 16 is a fuel supply mechanism,
18 is a fuel injection device, 20 is an accelerator pedal, 22 is a position sensor for the accelerator pedal 20, 24 is a pressure sensor that detects the pressure upstream of the throttle valve 12, 26 is a pressure sensor that detects the pressure downstream of the throttle valve 12, 28 is a computer. According to the fuel supply device configured in this way, the setting of the air-fuel ratio is uniquely instructed by the computer 28 based on the state of the engine,
Moreover, the control is performed with almost no time delay. That is, as shown in FIG. 2, the air-fuel ratio A/F is the first air-fuel ratio RA/
From the first engine state controlled by F1, at time t
1, when the air-fuel ratio A/F is shifted to the second engine state in which the air-fuel ratio A/F is to be set to the second air-fuel ratio A/F2 by depressing the accelerator pedal 2o, for example, the air-fuel ratio A/F
The control from A/F1 to A/F2 is performed in a relatively short time, and the air-fuel ratio A/F reaches A/F2 at time t2.

Therefore, the shorter the response time (t2t+), the more A/
The larger the difference in change from F1 to A/F'2, the more rapidly the engine condition changes, resulting in worse riding comfort. Furthermore, when the air-fuel ratio A/F changes to the rich side, fuel is wasted and fuel is supplied, resulting in a reduction in fuel efficiency.

In view of the above points, the present invention provides an electronic system that improves riding comfort and fuel efficiency during acceleration by gradually changing the air-fuel ratio when changing from a first air-fuel ratio to a second air-fuel ratio. The purpose of this invention is to provide an air-fuel ratio control method in a controlled fuel supply device, and the purpose is to control the air-fuel ratio by controlling the air flow rate to be supplied to the engine based on various engine information using an actuator operated by a computer. In an electronically controlled fuel supply system that is configured to perform This is achieved by an air-fuel ratio control method characterized in that the air-fuel ratio is changed as a function of time based on the magnitude of change in the fuel ratio.

The air-fuel ratio control method according to the present invention will be described below.The configuration of the electronically controlled fuel supply system itself is the conventional configuration shown in FIG. 1, and all air-fuel ratio control is processed within the computer 28. Next, the air-fuel ratio control method will be explained with reference to the flowchart shown in FIG. As soon as the engine condition changes from the first condition to the second condition, this is detected and the control method according to the invention is initiated. First, the first air-fuel ratio in the first engine state (the air-fuel ratio before the change)
A/F1 is read out, and then the second air-fuel ratio A/F2 in the second engine state after the change is read out by the computer 28.
The calculation is set by . The first air-fuel ratio A/F 1 and the second air-fuel ratio A/F2 are compared, and A/F 1 and A/F"2 are compared.
are not equal, A/F=t (A/F2-A/F1.
The fuel injection device 18 and throttle valve 14 are controlled to change the air-fuel ratio A/F so that A/F becomes A/F.
The process ends when F=A/F2. At this time, A/F gradually changes from A/F1 with a time delay, as shown in Fig. 4, and reaches A/F2 at time t2' (in the case shown, A/F is a linear function of time). ).

As described above, according to the present invention, the structure of the electronically controlled fuel supply device remains unchanged, but by changing the computer software, when changing the air-fuel ratio, the time function based on the magnitude of the change in the air-fuel ratio is changed. Since the air-fuel ratio is changed, the air-fuel ratio does not change suddenly, so the engine condition does not change suddenly, the ride comfort is improved, and even if the air-fuel ratio changes to the rich side, there is no waste It is extremely effective, as no fuel is supplied, resulting in better fuel efficiency, and since special equipment is required for this purpose, there is almost no increase in cost.

In the following description, the fuel priority type electronically controlled fuel supply system is described, but it goes without saying that the present invention is not limited to this and can be applied to other types of electronically controlled fuel supply systems.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a fuel priority type electronically controlled fuel supply system, Fig. 2 is a graph showing conventional air-fuel ratio control, Fig. 3 is a flowchart of the air-fuel ratio control method according to the present invention, and Fig. 4 is a method according to the present invention. It is a graph which shows air-fuel ratio control by. DESCRIPTION OF SYMBOLS 10... Engine, 12... Throttle valve, 14... Actuator, 16... Fuel supply mechanism, 18... Fuel injection device, 20... Accelerator pedal, 22... ...Position sensor, 24.26...
...Pressure sensor, 28...Computer. Agent Yasushi Shinohara

Claims (1)

[Scope of Claims] An electronically controlled fuel supply system configured to control the air-fuel ratio by controlling the air flow rate to be supplied to the engine based on various engine information using an actuator operated by a computer. When changing from one air-fuel ratio to a second air-fuel ratio in the next condition to be controlled, change the air-fuel ratio as a function of time based on the magnitude of the change from the first air-fuel ratio to the second air-fuel ratio. 1. An air-fuel ratio control method characterized by: