JPS63154829A - Electronic controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent slow speed hunting from occurring, by controlling a suction quantity for feedback to the desired value at the time of low speed and low load. CONSTITUTION:A throttle bypass valve 12 is installed in a suction pipe, and a suction pressure sensor 10 is installed in a surge tank 9. A control circuit 25 detects each signal out of various sensors including a car speed sensor or the like, and it controls a suction quantity for feedback according to the suction quantity, suction pipe pressure and a deviation between at least one of the values diving the suction quantity by engine speed and the desired value when the throttle valve is full-close and car speed and engine speed are less than the specified value. With this constitution, slow speed hunting is preventable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electronic control device for an internal combustion engine, and particularly to an electronic control device for an internal combustion engine that prevents light-speed hunting from occurring in a vehicle running at a low speed and at an operating point where the throttle valve is fully closed. First, stable operating conditions can be achieved.

[Conventional technology]

FIG. 1 shows a conventional electronic control device for an internal combustion engine according to the present invention, and the conventional device (for example, Japanese Patent Application Laid-Open No. 145332/1988) will be explained using FIG. In the figure, 1 is an engine, 2 is a piston, 3 is a cylinder, and 4 is a cylinder head. An exhaust manifold 6 is connected to the exhaust port 5 of each cylinder of the cylinder head 4, and an intake manifold 8 is connected to the intake boat 7. has been done. Further, the intake manifold 8 is provided with a surge tank 9 for preventing pulsation of intake air, and the surge tank 9 is provided with an intake pressure sensor 10 that detects the pressure within the intake manifold 8, that is, the intake pipe pressure Pm. 11 is a throttle valve that controls the amount of intake air sent to each cylinder via the surge tank 9; 12 is an idle speed control valve (KSCv) that controls the amount of intake air that flows through the bypass passage 12A that bypasses the throttle valve 11; 13; is an intake air temperature sensor that detects the intake air temperature, and the throttle valve 11 has a throttle valve opening sensor that outputs a signal according to the opening of the throttle valve 11, and an idle switch that is turned on when the engine 1 is being fitted. A throttle position sensor 14 is directly connected. Further, 15 is an oxygen concentration sensor attached to the exhaust manifold 6 and detects the oxygen concentration in the exhaust, 16 is a water quality sensor that detects the cooling water temperature of the engine 1, and 17 is a sensor that is connected to the spark plug 18 of the engine 1 at a predetermined timing. 20 is attached to the distributor 17 and generates a pulse I corresponding to the rotation speed Ne of the engine 1; 21 is a rotation speed sensor (not shown) that starts the engine 1; A starter sensor 22 detects the operating state of the starter motor, an air conditioner switch 22 detects the operating state of the air conditioner compressor, 23 is provided on a driven wheel to detect the running state of the vehicle, and the vehicle speed detects the number of revolutions thereof. It is a sensor.

Above-mentioned intake pressure sensor 10. Various detection signals from the intake air temperature sensor 13, throttle position sensor 14, M sensor 15, water temperature sensor 16, and rotational speed sensor 20 are output to a control circuit 25, and based on the above-mentioned detection signals, the control circuit 25 Various control processes such as fuel injection amount control of the fuel injection valve 26 and ignition timing control of the spark plug 18 are executed.

Next, the operation of the above-mentioned conventional device will be explained using the flowcharts of FIGS. 4 and 5. FIG. 4 shows a program for detecting the low-speed hunting state of the vehicle, that is, the unpleasant low-frequency vibrations caused by the rotation of the engine 1 and the longitudinal vibrations of the vehicle that occur along with this. In step 301, it is determined whether fuel is being cut off, in step 302 it is determined whether the throttle valve 11 is fully closed, and in step 303, the engine rotation speed Ne is a predetermined value (ioo).

rpm), and in step 304, whether or not the vehicle is running at low speed are determined by the slot ν.
This is performed from the outputs of the torque position sensor 14, rotation speed sensor 20, and vehicle speed sensor 23. Then, fuel injection is in progress, the throttle valve 11 is fully closed, the rotational speed is Ne<1000 (rpm), and the vehicle speed is 2.5k.
When driving at a low speed of more than m/h and less than 8 km/h,
When the above-mentioned judgment conditions are met, the process moves to step 305.

In step 305, flag X is set to "1" assuming that the condition is satisfied. On the other hand, if even one of the above judgment conditions is not satisfied, the process moves to step 306,
Flag X is reset to "0".

After the slow hunting state is detected by the determination routine shown in FIG. 4, the next process is performed based on the flag X setting result.

The routine shown in FIG. 5 is to be executed by the control circuit 25 before issuing a control output to the Eve knife 19 and causing the spark plug 18 to fire. First, step 401 is executed, and based on the outputs of the eight types of sensors shown in FIG. 1, the ignition timing θ, which is estimated to be optimal for the engine 1, is calculated by normal ignition timing control. Next, in step 402, the flag
TDC). As a result, the signal output to the igniter 19 is controlled by an ignition execution routine (not shown) executed by the control circuit 25 at a predetermined crank angle so as to be equal to the content θR. On the other hand, flag X is "
0”, the process moves to step 404, and step 401
The ignition timing θ using parameters such as the intake pipe pressure Pm and the engine speed Ne calculated in the above is stored as is in θR.

In this way, when the flag X is "1", the ignition timing is fixed at 109 BTDC regardless of the operating state of the engine 1. By repeating the above operations, rotation fluctuations are suppressed and slow hunting is prevented.

[Problem that the invention seeks to solve]

Conventional electronic control devices for internal combustion engines simply fix the ignition timing to a value that reduces the gain of rotational fluctuations after determining that the engine is in a slow-speed hunting state as described above. The problem is that once slow hunting with a large vA width of approximately 100 rpm occurs due to disturbances such as road surface changes, rotational oscillation cannot be completely stopped. There was a point.

This invention was developed in order to solve the above-mentioned problems, and even if slow-speed hunting with a large amplitude and a large rotation angle/width occurs, it reliably controls rotation fluctuations and stops oscillation. The object of the present invention is to obtain an electronic control device for an internal combustion engine that can perform the following steps.

[Means for solving problems]

The electronic control device for an internal combustion engine according to the present invention is based on the engine? I
A control means is provided for controlling the intake air amount in response to a deviation between a target value and at least one of the intake air amount of the engine, the intake pipe pressure, and the value obtained by dividing the intake air amount by the rotational speed when the engine is in the EI speed hunting state. It is something.

[For production]

The control means according to the present invention controls the intake air amount when at least one of the intake air amount, intake pipe pressure, and the value obtained by dividing the intake air amount divided by the rotation speed of the engine is larger than a target value, that is, when the deviation is positive when the engine is in a slow-speed hunting state. When the deviation is smaller than the target value, that is, when the deviation is negative, the intake air amount is increased. This results in
The above parameters are controlled to target values, and the engine speed is also
J is controlled.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. The configuration of the electronic control device is the same as that in FIG. 1, but the control circuit 25
The arithmetic processing and data settings in the arithmetic unit, which is centered around a microprocessor, are different from conventional ones.

Next, the operation will be explained with reference to the flowcharts of FIGS. 2 and 3. FIG. 2 shows a routine for determining a slow hunting state. Steps 101-103 are the same as steps 302-304 in FIG. Note that conventionally, in step 301, it is determined whether the fuel cut is not in progress, but in this embodiment, this determination process is not executed. this is,
If the fuel cut is performed below 1100 rpm, the engine will stall, so it is impossible to cut the fuel below 1000 rpm.
This is because the condition of 0 rpm or less is sufficient. Further, in this embodiment, in step 104, the ratio r=Ne/Ns between the engine speed Ne and the vehicle speed Ns is determined, and this ratio r is the predetermined value r. If it exceeds , it is determined that the gear is not in neutral and the process proceeds to step 105. Step 105
Then, as in the conventional step 305, set the flag X=1,
If the determination in steps 101 to 104 is No, the flag X is set to 0 in step 106, and the process is terminated.

Next, the intake air amount control process shown in FIG. 3 is carried out based on the processing result of the slow speed noching state determination routine shown in FIG.

Step 201 is a step of calculating the basic side N position SO that sets the lSCV 12 to a predetermined opening degree, and calculates the SO in accordance with the engine temperature and the load condition of the air conditioner. Next, when it is determined in step 202 that X=1, that is, the vehicle is in a slow hunting state, the process proceeds to step 203;
A gear ratio r is calculated from the rotational speed Ne and the vehicle speed Ns. Next, in step 204, a target intake pipe pressure Pd is set based on conditions such as the gear ratio and the load condition of the air conditioner. In step 205, the intake pipe pressure P and the target intake pipe pressure Pd (
Calculate the q difference ΔP. In step 206, this deviation Δ
A feedback EkS,1 proportional to the integral value of P is calculated. At this time, the integral gain is adjusted in step 2 as necessary.
Based on the gear ratio r calculated in step 03, it is possible to switch to an appropriate value. Next, in step 207, the basic control hi
A sum S of s0 and feedback ff1SN is calculated. It is obvious that when l5CV12 is controlled by this S, the intake pipe pressure deviation ΔP is reduced and the intake pipe pressure is controlled to the target value, so a detailed explanation will be omitted. On the other hand, if X\1 in step 202, that is, if there is no slow hunting state, the process moves to step 208 and the feedback amount S,1 is set to 0, so the above-mentioned control is not performed.

As described above, it is possible to prevent the intake pipe pressure from fluctuating due to slow hunting by controlling the amount of intake air, and accordingly no rotational speed fluctuations occur.

In the above embodiment, the target intake pipe pressure is set based on conditions such as the gear ratio and the load condition of the air conditioner, etc. However, instead of considering various road surfaces and load conditions in advance, the target intake pipe pressure Even more flexible control is possible by calculating the average value of the intake pipe pressures P and using this average value as the target intake pipe pressure Pd. Further, in FIG. 3, SN was obtained by integration, but the same effect can be achieved by obtaining it proportionally or by combining integral and proportional. Furthermore, although it was not determined whether the engine was in an accelerating state in the intake air amount control routine, after step 207, the engine speed, vehicle speed, throttle valve opening, intake air amount, intake pipe pressure, and intake air amount were changed. By determining that the engine is accelerating based on the value divided by a number, etc., and adding processing to set the intake l feedback amount SN-〇, the slow-speed hunting countermeasure and acceleration correction can be achieved without conflicting, resulting in a good driving feeling. is obtained.

Further, in the above embodiment, a speed density type fuel injection device is used as a specific example of the fuel injection system, but the present invention can also be applied to a fuel injection device using an air flow sensor or an electronically controlled carburetor system. In a fuel injection device using this air flow sensor, the control parameter is the intake air amount or the value obtained by dividing this by the rotational speed, and it is obvious that control is performed so that this value becomes the target value. , a detailed explanation is omitted.

〔Effect of the invention〕

As described above, according to the present invention, when the low-speed hunting state of the engine is detected based on the engine speed, vehicle speed, and load condition, the engine intake air volume, intake pipe pressure, and the value obtained by dividing the intake air volume by the engine speed are detected. The intake air amount is feedback-controlled according to the deviation between each engine and its target value, so that it can be quickly controlled to the target value no matter what rotational fluctuations occur.
Along with this, the rotation speed can also be controlled, preventing slow-speed hunting and always providing a good driving feeling.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional electronic handle device for an internal combustion engine according to the present invention, FIGS. 2 and 3 are flowcharts showing the operation of the device of the present invention, and FIGS. 4 and 5 are diagrams showing the operation of the conventional device. FIG. l... Engine, 10... Intake pressure sensor, 12... Idle speed control valve, 14... Throttle position sensor, 2o... Rotation speed sensor, 22゛... Air conditioner switch, 23... Vehicle speed sensor, 25・・・
control circuit.

Claims (4)

[Claims] (1) Means for detecting the vehicle engine speed, means for detecting the running speed of the vehicle, means for detecting that the engine is in the lowest load state, means for detecting the intake air amount or intake pipe pressure of the engine, A means for controlling the intake air amount, and at least one of the following: intake air amount, intake pipe pressure, and the value obtained by dividing the intake air amount by the rotation speed when the engine rotation speed and vehicle speed are within a predetermined range and the engine is in a minimum load state, and a target control means for generating a correction signal including at least one of an integral value and a proportional value of the difference between the target value and the correction signal and applying the correction signal to the intake air amount control means so as to reduce the difference between the target value and the target value; An electronic control device for an internal combustion engine characterized by: (2) Having means for detecting the transmission ratio of the engine or the ratio between the engine rotation speed and the vehicle speed, and changing at least one of the integral gain and the proportional gain in the correction signal according to the output of the means. An electronic control device for an internal combustion engine according to claim 1, characterized in that: (3) When the transient state of the engine is detected from at least one of the engine rotational speed, vehicle speed, throttle valve opening, intake air volume, intake pipe pressure, and the value obtained by dividing the intake air volume by the engine speed, the above correction is made. Claim 1 or 2, characterized in that the application of the signal to the intake air amount control means is stopped.
An electronic control device for an internal combustion engine as described in . (4) Calculate the average value of intake air volume, intake pipe pressure, and the value obtained by dividing intake air volume by rotational speed at each predetermined time period or at each predetermined engine crank angle, and use this average value as the above target value. An electronic control device for an internal combustion engine according to any one of claims 1 to 3, characterized in that: