JPH03206335A - Air-fuel ratio controller of internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to air-fuel ratio control of internal combustion engines, and particularly to control of engines such as automobiles.

[Conventional technology]

In the conventional device, as in Japanese Patent Application Laid-Open No. 64-8332, a plurality of exhaust pipes are provided for each cylinder group, and the detection level of each exhaust pipe is determined by the detection level of an auxiliary oxygen sensor installed at the collection point or downstream thereof. Since the independent air-fuel ratio feedback control is corrected, each cylinder group always has the same desired air-fuel ratio.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into account the air-fuel ratio at low-temperature start-up, and the air-fuel ratio varies among cylinders at low-temperature start-up. Additionally, there is a problem in that the air-fuel ratio at low temperature startup varies for each internal combustion engine.

An object of the present invention is to eliminate variations in the air-fuel ratio of each cylinder during a cold start.

An object of the present invention is to eliminate variations in air-fuel ratio among internal combustion engines.

[Means to solve the problem]

In order to achieve the above object, a heater is installed in the intake pipe of any one cylinder to prevent fuel from sticking to the inner wall.

In addition, the exhaust pipe of any l-cylinder equipped with this heater should be
It is equipped with two sensors.

Furthermore, fuel is supplied to each cylinder so that it can be injected into individual injection widths for each cylinder.

[Effect]

The heater in the intake pipe prevents fuel from sticking to the wall flow, so any cylinder can burn at an air-fuel ratio of 14.7. Furthermore, since fuel injection can be performed individually for each cylinder, and each cylinder equipped with a heater has its own 02 sensor, 02L feedback can be performed only in this cylinder even at low temperatures.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of the present invention.

Central processing unit (hereinafter referred to as CP) that performs digital arithmetic processing
Abbreviated as U. ), an internal combustion engine control device 1 that controls the internal combustion engine using sensors and actuators installed at any location on the internal combustion engine, an air flow meter 6 that converts the amount of air taken into the internal combustion engine into an electrical signal, and an engine crank. A crank angle sensor 5 that changes the angle into a digital signal, an injector 4 that injects fuel into the internal combustion engine according to a pulse signal from the internal combustion engine control device 1, an 02 sensor 2 attached to the exhaust pipe of a specific cylinder, The system consists of the 02 sensor 3 attached to the collecting part of the exhaust pipe.

FIG. 2 shows a cross-sectional view of a particular cylinder in which an 02 sensor 2 is installed. The feature in this figure is that a heater 11 is installed below the injector of the intake pipe.

FIG. 3 shows a block diagram of the internal circuit of the internal combustion engine control device. CPU 21 that performs digital calculation processing Drives external actuators and takes in information from sensors D i
/ 0 2 2, ROM 23 that stores the control program, control data, etc., R that stores variables of the control program
Consists of AM24.

FIG. 4 shows a block diagram of the fuel injection sequence inside the D i/O of the present control device. When each cylinder signal ref31 of the internal combustion engine is input, the crank angle signal pos32 of the internal combustion engine is inputted. Di/O internal register c
It is counted by counter3 3. The count value is reg 1 . 3 If the value exceeds 4, pos32
is counted by counter 2, 35. Contents of counter 2, 35 and reg2, 3
The comparison value of 6 is an inverted output and is output as a fuel injection width. FIG. 5 is a flowchart of the block diagram of FIG. Count at timing 41 of cylinder signal ref
Counter 1 starts counting, and counter 2 starts counting at the timing of counting end 42. The fuel injection width output to the outside is 43.

The internal combustion engine control device of the present invention includes the register configuration shown in FIG. 4 as many registers as there are internal combustion engines. FIG. 6 shows a flowchart of the present invention. It is assumed that this flow occurs due to a time interrupt or an interrupt caused by an external factor. In step 501, it is confirmed whether the ignition switch of the vehicle is ON or OFF. If it is ON, it is determined in step 502 whether the internal combustion engine is started at a low temperature or at a high temperature. If the engine is started at a low temperature, the process proceeds to step 503. In step 503, the heater attached to the intake pipe is turned on to prevent the fuel injected from the injector from liquefying in the intake pipe. In step 504, 02 feedback is started only for cylinders with heaters, and the air/fuel ratio (hereinafter abbreviated as A/F) is 14.7.
Control is performed so that

In step 505, it is monitored whether the cooling water of the internal combustion engine has risen. If the water temperature is low. 02 cylinder with heater
With the coefficient corrected from the feedback coefficient, the A of other cylinders is
/F to be around 8.0 (step 506
). The above-mentioned A/F value, such as 8.0, varies depending on the characteristics of each internal combustion engine, and is determined by matching. Step 507
determines whether the temperature of the internal combustion engine has increased. When the temperature rises, turn off the intake pipe heater.

FIG. 7 shows a calculation flowchart of the 02 feedback correction coefficient at low water temperature. The 02 feedback here performs PI control. αRL is the 02 feedback coefficient when the 02 sensor output changes from rich to lean.
, the average feedback coefficient at this time is α=(αRL+αLR)/2, assuming that the 02 feedback coefficient when changing from lean to rich is αLR. The correction coefficient for cylinders other than those with heaters is α=αXLCMP (LCMP is a matching constant). This is shown in steps 601-607.

FIG. 8 is a routine for calculating the injection width when the injector provided in each cylinder injects fuel. The fourth mentioned above
As shown in the figure, each cylinder can inject fuel with an individual injection width. When the temperature of the internal combustion engine becomes high, all cylinders are controlled using the normal 02 feedback coefficient, but when the water temperature is low, the cylinder with a heater uses the 02 feedback coefficient 7, and the other cylinders use the 02 feedback coefficient. (I, ; have been explained in Figure 7.)
According to this example, even when starting at a low temperature, each internal combustion engine can burn at a constant A/F without any difference.

〔Effect of the invention〕

According to the present invention, even when the internal combustion engine has a low water temperature, one cylinder has an A/
Since feedback control is performed at F14.7, there is no need to inject fuel in an unnecessarily high concentration, resulting in low fuel consumption.

Additionally, a heater is installed in the cylinder to warm up the cylinder, which has the effect of improving starting performance.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main structure of the present invention, FIG. 2 is a sectional view of the main features of the present invention, FIG. 3 is a circuit block diagram of the control device of the present invention, and FIGS. 4 and 5 1 is a diagram showing a register configuration diagram and a time chart of a fuel injection sequence of a control device of the present invention, and FIGS. 6, 7, and 8 are diagrams showing flow charts of control according to the present invention. 1... Internal combustion engine control device, 2, 3... 02 sensor,
4 Figure 1 ≦ Figure 2 Figure 3 Figure 1 Figure 4 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. In an internal combustion engine control device that is equipped with an air-fuel ratio sensor that is attached to an exhaust pipe and whose output changes depending on the components in the exhaust gas, and means that can inject fuel into two or more cylinders with different injection widths, an arbitrary one An internal combustion engine air-fuel ratio control device, characterized in that only a cylinder always performs air-fuel ratio control based on the output of the air-fuel ratio sensor, and other cylinders perform fuel control at a constant air-fuel ratio by referring to their air-fuel ratio control coefficients.