JPH04350340A - Air-fuel ratio controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To make improvement of acceleration, fuel consumption and emission compatible at the time of increasing a quantity of high load. CONSTITUTION:There are provided operation condition detection means 31, 38 which detect the operation condition of an internal combustion engine, a basic injection quantity calculation means 40 which calculates a basic fuel injection quantity required by the internal combustion engine based on the operation condition, a high-load increase quantity setting means 40 which sets a basic high-load increase quantity value for increasingly correcting the basic injection quantity based on a high-load condition, and shift position detection means 38, 50 which detect the shift position of an internal combustion engine, a high-load detection means 31 which detects the high-load condition of the internal combustion engine. This controller is characterized in provision of correction means 40 which corrects more greatly the basic high-load increase quantity as the shift position is lower, and a final injection period setting means 40 which corrects the basic injection quantity and sets the final injection period based on the value corrected by the correction means.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-fuel ratio control device for an internal combustion engine, and more particularly to an air-fuel ratio control device characterized by a method of increasing the amount at high loads.

0002

2. Description of the Related Art Conventionally, there has been an electronically controlled fuel injection control device that detects the operating state of an internal combustion engine and determines the fuel injection amount of the internal combustion engine in accordance with the operating state. This type of fuel injection control device calculates the basic injection amount based on the engine's intake pipe pressure and engine speed, and increases the basic injection amount during high-load operation such as during acceleration to increase the engine output. Various methods have been proposed to increase the temperature. Furthermore, in order to suppress the deterioration of fuel efficiency due to a high load increase, the amount is not increased when the shift position is at the top, and when the shift position is other than the top, the amount is uniformly increased regardless of the shift position. What is disclosed is disclosed.

0003

However, if a high load increase is not performed when the shift position is at the top, as in the above-mentioned device, for example, acceleration during high-speed driving will be impaired. Also, if a high load is increased uniformly when the shift position is other than the top, for example, when the shift position is 1st to 3rd in a 4-speed car, a commensurate high load increase will be made when climbing a hill or accelerating suddenly, but During acceleration, the shift position is usually 1st or 2nd speed, and even when running in 3rd speed, where output is not so necessary, the same increase as in 1st and 2nd speeds is applied, resulting in a problem of deterioration of fuel efficiency and emissions.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an air-fuel ratio control device that achieves both acceleration performance and improvements in fuel consumption and emissions during high-load operation.

[0005]

[Means for Solving the Problems] As a means for solving the above problems, the present invention provides an operating state detection means for detecting the operating state of an internal combustion engine, and a basic injection that is requested by the internal combustion engine based on the operating state. a basic injection amount calculation means for calculating the amount, a high load detection means for detecting a high load state of the internal combustion engine, and a basic high load increase value for increasing the basic injection amount based on the high load state. a high load increase setting means for setting a high load increase; a shift position detection means for detecting a shift position of the internal combustion engine; a correction means for correcting the basic high load increase to a greater extent as the shift position is lower; The present invention provides an air-fuel ratio control device for an internal combustion engine, comprising: final injection time setting means for correcting the basic injection amount based on the value and setting a final injection time.

[0006]

[Function] As a result, when the shift position is low and the load is high, the basic injection amount is increased to a greater extent than when the shift position is high, and the air-fuel ratio is controlled with emphasis on acceleration, and when the shift position is high and negative, The basic injection amount is increased by a small amount, and the air-fuel ratio is controlled with emphasis on fuel efficiency and emissions.

[0007]

Embodiment FIG. 2 shows a first embodiment in which the fuel supply amount control device for an internal combustion engine of the present invention is applied to an internal combustion engine for a gasoline-powered automobile.

In the figure, an internal combustion engine 1 has a cylinder 2.
, piston 3, cylinder block 4, cylinder head 5
It has a combustion chamber 6 formed by. The above combustion chamber 6
A spark plug 7 is disposed in the engine. The rotational driving force from the piston 3 is transmitted to drive wheels (not shown) via various devices such as a transmission (not shown). Furthermore, the rotational driving force rotates a generator (not shown) to supply power to each device, and is also stored in a power supply battery (not shown).

The intake system of the internal combustion engine 1 communicates with an upstream intake pipe 9 via an intake valve 8 of the combustion chamber 6, and a surge tank 10 is provided upstream of the intake pipe 9 to absorb pulsation of intake air. A throttle valve 11 is disposed upstream of the surge tank 10. The throttle valve 1
1, the opening degree is adjusted by the driver's operation of accelerating or decelerating the accelerator pedal 12.

On the other hand, the exhaust system of the internal combustion engine 1 includes a combustion chamber 6
The exhaust valve 16 passes through an exhaust pipe 17 and a catalytic converter 17a for purifying exhaust gas. The fuel system includes a fuel supply source consisting of a fuel tank and a fuel pump (not shown), a fuel supply pipe, and a fuel injection valve 18 disposed in the intake pipe 9.
It is made up of.

The ignition system also includes an igniter 19 that outputs the high voltage necessary for ignition, and a distributor that distributes the high voltage generated by the igniter 19 to the spark plug 7 in conjunction with a crankshaft (not shown). It is composed of 20 pieces.

The internal combustion engine 1 further includes, as detectors, an air flow meter 31 provided in front of the intake pipe 9 to measure the intake air flow rate, and an intake temperature sensor provided in the intake pipe 9 to measure the intake air temperature. 32, a vehicle speed sensor 50 that detects vehicle speed, a throttle position sensor 33 that detects the opening degree of the throttle valve in conjunction with the throttle valve 11, and a water temperature sensor 34 that is installed in the cooling system of the cylinder block 4 and detects the coolant temperature. , and an oxygen sensor 35 provided in the exhaust pipe 17 to detect residual oxygen in the exhaust gas.
Equipped with The throttle position sensor 33 includes an idle switch that outputs an on signal when the throttle valve 11 is fully closed.

[0013] Also, inside the distributor 20, 1/2 of the camshaft of the distributor 20 is provided.
A rotation angle signal N is generated every four rotations, that is, every integer multiple of the crank angle from 0° to 30°, and every rotation of the camshaft of the distributor 20, that is, the rotation angle signal N of the crankshaft (not shown) is generated.
A rotation sensor 38 is provided that outputs two crank angle position signals G1 and G2 once each rotation.

The signals from each of the above sensors are input to an electronic control unit (hereinafter simply referred to as ECU) 40, and the ECU 40 controls the internal combustion engine 1 based on these signals and other information. There is.

Next, the configuration of the ECU 40 will be explained based on FIG. 3. ECU40 is CPU40a, ROM4
0b, RAM 40c, backup RAM 40d, clock 40z, etc. as a logical operation circuit. The ECU 40 includes a common bus 40e, an input/output port 40f, an input port 40g, and an output port 40.
External input/output is performed via h. The power supply circuit 41 is connected to an energizing line 42, and the energizing line 42 is connected via a key switch 43 to a battery 44 for power supply and storage.

The backup RAM 40d is configured so that even when the key switch 43 is turned off and power is no longer supplied to the ECU 40, it is supplied with power from another power supply circuit 46 and retains its stored contents.

The ECU 40 has buffers 40i, 40j, 40k, 40w for the detection signals of the sensors described above, a multiplexer 40n, and an A/D converter 40p, and these detection signals are sent to the CPU 40a via an input/output port 40f. is input.

The ECU 40 also includes a buffer 40q for the oxygen detection signal, a comparator 40r, and a waveform shaping circuit 4 for the signal from the idle switch 33 and the signal from the rotation sensor 38.
0s, and these signals are input to the CPU 40a via the input port 40g.

Furthermore, the ECU 40 includes a drive circuit 40u for the fuel injection valve 18 and a drive circuit 40 for the igniter 19, which have already been described.
y, and the CPU 40a outputs a control signal to both drive circuits 40u and 40y via an output port 40h.

Next, the fuel injection amount control executed by the ECU will be explained based on the flowcharts shown in FIGS. 4 to 6. FIG. 4 shows a routine for setting the final injection amount (Ti) that is started and executed every 360°C. In step 101, the basic injection amount is Calculate TP.

[0021]

[Formula 1] TP=K×Q/Ne where K is a constant. Next, in step 102, the basic injection amount TP calculated in step 101 is corrected using the following arithmetic expression, and the final injection time Ti is set.

[0022]

[Math. 2] Ti=TP×(1+K1+C)+Tv where K
1 is various correction coefficients determined by water temperature, etc., C is a high load increase correction coefficient determined by a routine described later, and Tv is an invalid injection time.

FIG. 5 shows a routine that is executed at predetermined time intervals (for example, every 50 msec) and sets a shift position correction value according to the shift position. First, in step 201, the quotient (Ne/SPD) of the engine speed Ne and the vehicle speed SPD is calculated and stored as X. Next, in steps 202 to 204, the current shift position is determined based on X. That is, when X is greater than or equal to the judgment value β1, the first speed and step 20 are selected.
6, and when X is less than the judgment value β1 and more than the judgment value β2, it is judged as 2nd speed at step 207, and when X is less than the judgment value β2 and more than the judgment value β3, step 208
It is determined that it is in 3rd gear. Further, when X is smaller than the determination value β3, it is determined that the vehicle is in the fourth speed and in step 205, the vehicle is in the fourth speed.

Generally, if the shift position is constant, the engine speed Ne and the vehicle speed SPD are in a proportional relationship, and the lower the shift position, the larger X becomes, so the determination values β1, β2, and β3
can be determined in advance according to the shift position through experiments, etc.
The relationship is β1>β2>β3.

When the shift position is determined as described above, the process proceeds to step 209, where a shift position correction value B corresponding to the shift position is calculated from the map shown in FIG. Here, the shift position correction value B is set to take a larger value as the shift position is lower, as shown in FIG.

FIG. 6 shows a routine for setting the high load increase correction coefficient C, which is activated and executed every 50 msec. First, in step 301, the high load increase correction coefficient C is set to 0. Then, in step 302, it is determined whether the operating state is high load or not, based on whether the intake air amount Q is less than a predetermined value α.If the intake air amount Q is in the high load state, step 303 is performed to determine the basic high load increase value (for example, 0.
2) is set to A. Then, in step 304, the product of the shift position correction value β obtained by the routine shown in FIG. 5 and the basic load increase value A is set as the high load increase correction coefficient C.

[0027]

[Equation 3] C←A×B Here, the high load increase correction coefficient C becomes a larger value as the shift position is lower, and the basic injection amount TP is greatly increased when the shift position is lower, improving acceleration. , when the shift position is high, the amount is increased by a small amount and fuel efficiency is improved.

In the embodiment described above, the shift position is determined from the engine speed Ne and the vehicle speed SPD, but a shift position switch or the like may be provided to directly detect the shift position.

[0029] Furthermore, the basic high load increase value is a constant value (0.2
) may be set according to the operating condition, such as a variable value according to the engine speed.

[0030]

According to the present invention described above, the high load increase is set to be larger as the shift position is lower. Therefore, during high-load operation where the shift position tends to be low, such as when climbing a slope or sudden acceleration, the basic injection amount is greatly increased and acceleration performance is improved, and during high-load operation when driving at the same high shift position during general driving. Since the increase in fuel consumption is kept low and deterioration of fuel efficiency and emissions is suppressed, there is an excellent effect of improving acceleration and suppressing deterioration of fuel economy and emissions during high-load operation.

[Brief explanation of drawings]

FIG. 1 is a complaint correspondence diagram.

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of an ECU and its surroundings.

FIG. 4 is a flowchart showing the operation of the ECU when setting the final injection time.

FIG. 5 is a flowchart showing the operation of the ECU when setting a shift position correction value.

FIG. 6 is a flowchart showing the operation of the ECU when setting a high load increase correction coefficient.

FIG. 7 is a characteristic diagram showing the relationship between shift position and shift position correction value.

[Explanation of symbols]

31 Air flow meter 38 Rotation sensor 40 ECU 50 Vehicle speed sensor

Claims (1)

[Claims] 1. Operating state detection means for detecting an operating state of an internal combustion engine; basic injection amount calculation means for calculating a basic injection amount required by the internal combustion engine based on the operating state;
a high load detection means for detecting a high load state of the internal combustion engine; a high load increase setting means for setting a basic high load increase value for increasing the basic injection amount based on the high load state; a shift position detection means for detecting a shift position of the engine; a correction means for correcting the basic high load increase to a greater extent as the shift position is lower; and a correction means for correcting the basic injection amount based on the value corrected by the correction means. An air-fuel ratio control device for an internal combustion engine, comprising: final injection time setting means for setting a final injection time.