JPS58200059A - 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 The present invention detects an air-fuel ratio from exhaust gas components of an internal combustion engine,
The present invention relates to an air-fuel ratio control device for an internal combustion engine that controls the air-fuel ratio according to this detection signal.

In conventional air-fuel ratio control devices for internal combustion engines, the basic fuel amount is determined using an intake air amount sensor that detects the intake air amount of the internal combustion engine, and the air-fuel ratio is determined by detecting the oxygen concentration in the exhaust gas of the internal combustion engine. The air-fuel ratio was controlled to be the stoichiometric air-fuel ratio by making corrections using integral control using sensors.

This is to compensate for the detection error of the intake air amount sensor through feedback control by the sensor, but if the error becomes large, the air-fuel ratio will fluctuate during transient periods due to a delay in correction of the integral control. Furthermore, if the hexensor is inactive, feedback control cannot be performed, making precise air-fuel ratio control impossible. For this reason, the integral control is performed when the fuel sensor is active, the average value of the integral values corresponding to each operating state of the engine is stored, and this value is used as a correction amount to reduce fluctuations in the air-fuel ratio. So-called learning control is being performed. However, in conventional learning control, when the operating state of the engine changes, 0. Since the sensor remains lean or rich (when the air-fuel ratio is thicker than the stoichiometric air-fuel ratio, it is called rich, and when it is thinner, it is called l-1), the integral value temporarily changes greatly, and the correction l by learning control is There is a drawback that the operating conditions differ greatly compared to when they do not change.

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and the present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional art. By not updating the above-mentioned correction 11 for a predetermined period of time from that point on, the correction sound by learning will not be affected even if the operating state of the engine changes, and thereby the air-fuel ratio can be controlled precisely. An object of the present invention is to provide an air-to-furnace ratio control device for an internal combustion engine.

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

FIG. 1 shows an air-fuel ratio control device for an internal combustion engine according to the present embodiment, and 100 calculates the fuel injection amount from various input information obtained from the internal combustion engine, and based on this calculates the fuel injection amount from the injector (fuel injection device j'). 6 to control the internal combustion engine to a predetermined air-fuel ratio, and the control circuit ioo is controlled by the CPU
01, an interrupt processing section 102, a digital input processing section 103, an analog input processing section 104, a RAM 105, power supply circuits 106, 107, a ROM 108, a timer 109, and an injector drive circuit 110. CPU10
The interrupt processing unit 102 calculates and controls the 1Fi fuel injection amount, and the rotation detector 1 detects the rotation speed of the internal combustion engine.
The waveform of the signal is shaped and an interrupt signal is sent to the CPU 10I in synchronization with the rotation speed. Digital input processing section 103F
It receives a digital signal from a digital signal generator 2 such as an i-start switch or an idle detection switch, adjusts the level of this signal, and transmits it to CPUl0I. Analog input processing unit 104Fi consists of an analog multiplexer and an A/D converter, and inputs battery voltage, cooling water temperature, intake pipe negative pressure,
0! Analog signals from an analog signal generator 3 such as a sensor are sequentially A/D converted and transmitted to the CPU10IK. The RAM 105 that stores data is backed up by a power supply circuit 106 directly connected to the battery 4, and its stored contents are retained even when the key switch 5 is turned off. Power supply circuit 107
#i Performs other power supply for the control circuit 100. Also, R
The OM 108 stores a program and serves as a timer for internal calculations of the CPU 01 such as timer 109 cycle measurement, and a timer for outputting the drive cycle and drive pulse width of the injector 6. The injector drive circuit 110 is a timer 109
The injector 6 is driven in response to a signal from the injector 6. The above device obtains various information from the internal combustion engine via the 02 sensor, etc., and controls the fuel injection amount in accordance with this information so that the air-fuel ratio becomes a predetermined air-fuel ratio.

FIG. 2 is a time chart for explaining the operation of the above-mentioned device, and FIG. 3 is a flow chart for the operation of the CPU 10I for realizing the operation shown in the time chart of FIG. In FIG. 2, 1 indicates the output of the 02 sensor, with the upper side being rich and the lower side being full. 2 is O
The output of the counter 1 is set to a predetermined value A each time the t sensor becomes rich or lean, and is then counted down and the value is clipped at the lower limit value B. 3 indicates the output of the flip-flop which is set when the count value of the counter 1 reaches the lower limit value B and is reset after a predetermined time. 4 is 0. It shows the integral value of the sensor, and 5 shows the time. As shown in Figure 2, the distinction between the duration of lean and rich during feedback of normal sensor output when the operating condition does not change and the duration of lean and rich when the operating condition changes is shown in 2. This can be done freely by setting the countdown cycle of color/re1 and the predetermined value A1 lower limit value B. Further, the set period of the flip 70 knob shown in 3 is set to the time when the integral value of the 02 sensor shown in 4 converges sufficiently, and the correction amount by the school fund control is not updated during this period.

On the other hand, in FIG. 3, the learning process in step 200 is one of the processes in the main routine, and the learning process in step 201 is one of the processes in the main routine.
If the learning condition is not satisfied, that is, during feedback control using six sensors, the cooling water temperature is above a predetermined value, and the sensor output is inverted to rich, and if this learning condition is not satisfied. If the flip-flop is in the set state in step 202, the learning value, that is, the average value of the integral value of the sensor output is not updated, and correction is performed in step 204 using the original learning value. Further, if the above learning condition is satisfied and the flip-flop is in the reset state, the learning value is updated in step 203, and correction is performed using the updated learning value in step 204.

Further, the interrupt processing shown in step 300 is a routine that is processed periodically, and steps 301 to 304 are shown in FIG.
2) shows the operation of the counter 1, and when the polarity of the duck sensor is reversed between rich and lean, set the counter directly to 'kA' and set it to 0. Counts down while the sensor output is rich or lean and the polarity does not reverse. Count value is lower limit B
When the countdown is reached, the countdown is stopped and the flip-flop is set in step 305. Steps 306-31
0ilt slip 70 knob operation, flip 70
When the knob is in the reset state, a predetermined value is set in the counter 2 in step 307, and when the flip-flop is in the set state, a countdown is started in step 310, and when the count value reaches zero, the flip-flop is reset. .

As described above, in the present invention, when the operating state of the engine changes, this is detected by the output of the air-fuel ratio detection means continuing to be in a rich or lean state for a predetermined time, and from that point on, the engine is idle for a predetermined time. The update of the average value of the integral value in the output of the air-fuel ratio detecting means as the fuel ratio correction amount is temporarily stopped, so that the air-fuel ratio correction amount is adjusted to the above-mentioned integral value that changes greatly when the operating condition changes. The air-fuel ratio can be controlled with high accuracy without being influenced by the air-fuel ratio.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an air-fuel ratio control device for an internal combustion engine according to the present invention, FIG. 2 is a time chart for explaining the operation of the air-fuel ratio control device for an internal combustion engine according to the present invention, and FIG. 2 is a flowchart for explaining the operation of the CPU. 1... Rotation detector, 2... Digital signal generator,
3... Analog signal generation section, 6... Injector,
100... Control circuit, 101... CPU, 102
... Interrupt processing section, 103... Digital input processing section, 104... Analog input processing section, 105...
RAM, 108...ROM, 109...Timer,
110...Injector drive circuit. Agent Makoto Kuzuno - Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) 'Equipped with an air-fuel ratio detection means for detecting the air-fuel ratio from the exhaust gas components of the internal combustion engine, and controls the air-fuel ratio by making corrections based on the integral value of the output of the air-fuel ratio detection means. In an air-fuel ratio control device for an internal combustion engine, the average value is stored in a storage device and is used as the total average value when correction by the integral value is inappropriate. lean matati IJ
An air-fuel ratio control device for an internal combustion engine, characterized in that when the latched state is continued, updating of the correction amount based on the average value is temporarily stopped for a predetermined period of time from that point onward.