JPS63124868A - Electronic control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To surely control a change of engine speed, by performing a feedback control of the ignition timing in accordance with a deviation, generated between the output of an engine speed detecting means and the target engine speed, when a throttle valve is placed in a fully closed condition. CONSTITUTION:When an engine is placed in a condition with a throttle valve 11 fully closed and an engine speed of 1,000rpm or less further with operation in running at a low speed, gear ratio is calculated if the engine is decided to be in a fine speed hunting condition. Next a deviation, obtained between the target engine speed set in accordance with a map and the engine speed by a sensor 20, is calculated, and on the basis of this deviation, an ignition timing feedback value is calculated. A sum of this value and the basic ignition timing is obtained, and on the basis of the above sum, a feedback control is executed. In this way, a good feeling of driving can be obtained by preventing the generation of fine speed hunting and suppressing a change of engine speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an internal combustion engine control device with an electronic fuel injection device, and particularly in a vehicle running at a low speed and at an operating point where the throttle valve is fully closed. , which allows stable driving conditions to be achieved without unpleasant low-frequency imaging of the internal combustion engine's rotational speed and the accompanying longitudinal perturbation of the vehicle (hereinafter, this phenomenon is referred to as slow-speed hunting). It is.

[Conventional technology]

FIG. 1 shows the configuration of a conventional electronic control device for an internal combustion engine and the present invention which will be described later. This will be explained with reference to FIG.

In this Fig. 1, l is the engine, 2 is Bizton, and 3
is the cylinder, 4 is the cylinder head 0, the exhaust boat 5 of each cylinder of the cylinder head 4 has an exhaust manifold 6, and the cylinder head 4 is the cylinder head 0. 4(D) An intake manifold 8 is connected to the intake boat 7 of each cylinder.

Further, the intake manifold 8 is provided with a surge tank 9 for preventing pulsation of intake air, and the surge tank 9 contains the pressure inside the intake manifold 8, that is, the intake pipe pressure Pm.
An intake pressure sensor 1° is provided to detect the intake pressure.

Next, 11 is a throttle valve that controls the amount of intake air sent to each cylinder via the surge tank 9, and 12 is an idle speed control/gurug that controls the amount of intake air that flows through the 24751 passage 12A that bypasses the throttle valve 11. (15CV), 13 id It is an intake pressure sensor that detects the intake air temperature, and the throttle valve 11 has a
A throttle valve opening sensor 14 that includes a throttle valve opening sensor that outputs a signal corresponding to the opening of the throttle valve 11 and an idle switch that is turned on when the engine 1 is idling 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 temperature sensor that detects the cooling water temperature of the ennon 1, and 17 is the engine 1
a distributor that applies a high voltage output from the igniter 19 to the spark plug 18 at a predetermined timing;
Reference numeral 0 denotes a rotation speed sensor that is attached to the distributor 17 and generates a distortion signal corresponding to the rotation speed Ne of the engine 1.

On the other hand, 21 is a starter sensor that detects the operating state i of a starter motor (not shown) that starts the engine, 22 is an air conditioner switch that detects the operating state of an air conditioner, and 25 is a follower sensor that detects the running state of the vehicle. This is a vehicle speed sensor that is installed on the driving wheels and detects their rotation speed.

Various detection signals from the intake pressure sensor +jio, intake temperature sensor 13, throttle body sensor i4, oxygen concentration sensor 15, water temperature sensor 16, and rotational speed sensor 20 are output to the control circuit 25. Based on each of the detection signals described above, 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 ignition timing control corresponding to the present invention, which will be described later with respect to the operation of the conventional example, will be explained.

The operation is made up of two processes, and the routine for determining whether the slow hunting operation range has been entered and the routine for controlling the ignition timing based on the results of this process will be described below.

First, the low-speed hunting state determination routine is for engine 1.
9 is executed by a CPU (not shown) in the control circuit 25 at predetermined time intervals. FIG. 6 is a 70-chart showing this processing routine. In this FIG. 6, step 301 determines whether or not the control ea is being executed during fuel cut, and step 302 determines whether the throttle valve is fully closed. Stain 2302 determines whether the engine rotation speed Ne is below a predetermined value (1000 (rPm)), and Stain 2304 determines whether the vehicle is running at low speed. Throttle motion sensor 14, rotation speed sensor 20. ]E2i Senp2
Judgment is made from the output of step 3. Then, while fuel injection is in progress, the rotation speed Nf3<1000 with the throttle valve fully closed.
(rpm) and the vehicle is traveling at a low speed of 2.5 Km/h to 8 Km/h or less, the above determination conditions are met and the process moves to step 305.

In this step 305, flag X is set in rlJ assuming that the condition has been met. 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 rOJ.

After the slow hunting state is detected by the above determination routine, the next process shown in FIG. 7 is performed based on the setting result of the flag X.

The routine shown in FIG. 7 is executed by the control circuit 25 before outputting a control output to the igniter 19 and causing the spark plug 18 to fire.

First, step 401 is executed, and based on the output of each glaze sensor shown in FIG.
Calculated.

In the following step 402, 7 lag
DC)? Store.

As a result, the signal output to the igniter 19 is controlled by the ignition execution routine (not shown) which is executed by the control circuit 25 at a predetermined crank angle so as to be equal to the content θR.

On the other hand, if the 7 lag
The ignition timing θ with parameters such as , engine speed Ne, etc. is stored as is in θR.

In this way, when the flag X is "1", the ignition timing is fixed at 10BTDC 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 fuel injection systems only fix the ignition timing after determining that slow speed hunting is occurring as described above, so they only suppress the occurrence of rotational fluctuations due to slow speed hunting, and - when the road surface changes. When slow hunting with a rotation fluctuation width of about 10 Orpm and a vibration frequency of about 1.3 Hz occurs due to disturbances such as these, there is a problem in that the rotational oscillation cannot be controlled.

This invention was made to solve such problems, and has a rotational fluctuation width of approximately 10 Orpm and a vibration frequency of approximately 1.
．． It is an object of the present invention to provide an electronic control device for an internal combustion engine that can reliably control rotational fluctuations and stop oscillations even if 3 Hz slow hunting occurs.

[Means for solving problems]

The electronic control device for an internal combustion engine according to the present invention sets a target rotation speed, calculates a rotation speed deviation from the target rotation speed,
A means is provided for controlling the ignition timing according to the rotational speed deviation.

[For production]

In this invention, when the engine speed is larger than the target value, that is, when the rotation speed deviation is positive, the ignition timing is retarded, and when the engine speed is υ smaller than the target value, that is, when the rotation speed deviation is negative, the ignition timing is retarded. In this case, the engine speed is feedback-controlled to the target engine speed by fully controlling the ignition timing to advance the engine speed.

〔Example〕

Embodiments of the electronic control device for an internal combustion engine according to the present invention will be described below with reference to the drawings, although the configuration of the present invention is exactly the same as that shown in FIG. 1 described above.

The method of arithmetic processing and data setting in the arithmetic section centered on a microprocessor (not shown) in the control circuit 25 is different from conventional devices, and the arithmetic procedure is shown in the flowcharts of FIGS. 2 and 3. Ru.

FIG. 2 shows a routine for determining a slow hunting state. Steps 101 to 103 are the same as steps 302 to 304 in the flowchart of FIG. 6 showing the conventional example, so the explanation will be omitted.

In the conventional example, it is determined in step 301 whether the fuel cut is not in progress, but in the present invention, this determination process is not performed.

This is because if the fuel cut is performed below 100 rpm, the engine will stall (so-called engine stall), so the fuel cut below 1000 rpm cannot be avoided, and if the engine speed in step 102 is 100° rpm. This is because the following conditions are sufficient.

5. According to the present invention, in step 104, the ratio r = Ne/N8 between the engine speed Ne and the vehicle speed N8 is determined, and if this ratio exceeds a predetermined value, it is determined that the gear is not in neutral. After making a judgment, the process proceeds to step 105.

In step 105, flag
The process ends with the flag set to X.

Next, the ignition timing control process shown in FIG. 3 is performed based on the processing results of the slow engine running state determination routine shown in FIG. Steps 201 to 202 are the same as steps 401 and 402 in FIG. 7 of the conventional example, so their explanation will be omitted.

If it is determined in step 202 that the vehicle is in the slow speed I/NT state, that is, YES, the process proceeds to step 203, where the ear ratio R is calculated from the ratio E=Ne/NB of the rotational speed Ne and the vehicle speed N8. In this calculation, for example, the following judgment logic is used.

If r1≧r)rz, then 1st gear r,≧r)
rz then 2nd gear r3≧r) r4 then 3rd gear However, rl + r! +r3+r
, is a constant determined by the transmission structure of the engine.Next, in step 204, step 20
The target rotational speed Nd is set according to a map optimally determined in advance corresponding to the gear ratio R calculated in step 3 and the on/off state of the air conditioner switch 22.

In step 205, the rotation speed Ne and the target rotation speed Nd
The deviation ΔN=Ne −Nd t− is calculated. Then, in step 206, the ignition timing feedback coefficient θPB is calculated using the relationship between the deviation ΔN and the ignition timing feedback coefficient θFB as shown in FIG. 4, for example.

In step 207, the ignition timing θ to be finally executed
is determined as the sum of the basic ignition timing θB determined in step 201 and the ignition timing difference θB.

On the other hand, if it is determined in step 202 that 7 lag
In step 8, the ignition timing feedback value θFB is set to 0, and the process proceeds to step 207, where the processing of the ignition timing control routine ends.

The above-mentioned operations are repeated, and the rotational speed is feedback-controlled so as to reach the target rotational speed, thereby actively controlling unpleasant rotational fluctuations caused by slow-speed hunting.

In the above embodiment, the relationship shown in FIG. 3 is used when calculating the ignition timing feedback value θFE, but the relationship shown in FIG. 5 may also be used.

Further, in the above embodiment, the target rotation speed is determined according to a predetermined map, but instead of considering various road surfaces and load conditions in advance, the rotation speed Ne is determined at each predetermined time or every predetermined crank angle. By calculating the average value of Nd and using this average value as the target rotational speed Nd, flexible control of the sea level becomes possible.

Furthermore, when performing averaging processing for each predetermined crank angle, processing is performed in synchronization with the expansion stroke of a specific cylinder, the average rotational speed for each cylinder of the engine is calculated, and the rotational speed deviation fcx is calculated for each cylinder. Depending on this result, the process of the embodiment shown in FIG. 3 may be performed for each cylinder.

In addition, in the above embodiment, the ignition timing feedback value was determined in a constant relationship regardless of the gear ratio, but considering that the ignition timing feedback value increases with the slow hunting vibration frequency and the gear ratio,
A relationship diagram of ignition timing feedback values may be set for each gear ratio.

Furthermore, in the above embodiment, it is not determined that the engine is in an accelerating state in the ignition timing processing routine, but if the throttle valve opening and rotation speed exceed predetermined values after step 207, By determining that the engine is in an accelerating state and adding processing to set the ignition timing feedback value θFB to 0, countermeasures against slow speed hunting and acceleration correction will not conflict with each other.
In the above explanation, a speed density type fuel injection device was used as a specific example of the fuel injection system, but it can also be applied to a fuel injection device using an air 70-sensor or an electronically controlled carburetor system. Needless to say.

〔Effect of the invention〕

As described above, the present invention determines the low speed hunting state based on the engine speed, vehicle speed, throttle valve position, and gear position calculated from the speed and vehicle speed, and sets or calculates the target rotation speed according to the running state of the vehicle. Since the ignition timing is controlled by feel pack according to the deviation of the rotation speed from the engine speed, it is possible to prevent the occurrence of slow speed hunting, and even if rotation fluctuations occur, the rotation speed can be quickly controlled to the target rotation speed, and a good driving feeling can always be achieved. You can get a ring.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an electronic control device for an internal combustion engine according to the present invention and a conventional one, FIGS. 2 and 3 are flowcharts showing the operation of the electronic control device for an internal combustion engine according to the present invention, and FIGS. Fig. 5 is a characteristic diagram of the ignition timing feedback gain in the electronic control device for an internal combustion engine according to the present invention.
7 and 7 are flowcharts illustrating the operation of a conventional electronic control device for an internal combustion engine. 1... Engine, 10... Intake pressure booster, 11...
・Throttle valve, 13...Intake temperature sensor, 14・
... Throttle indication sensor, 15... Oxygen concentration sensor, 16... Water temperature sensor, 19... Igniter, 2°... Rotation speed sensor, 22... Air conditioner switch, 23... Vehicle speed sensor, 25...control circuit.

Claims (4)

[Claims] (1) In an electronic control device for an internal combustion engine, the electronic control device for an internal combustion engine controls the output of the internal combustion engine by controlling the ignition timing of the internal combustion engine according to a detection result of an operating state detection means that detects the operating state of the internal combustion engine for a vehicle. The rotation detection means includes a rotation detection means for detecting the rotation speed of the internal combustion engine, a vehicle speed detection means for detecting the vehicle speed of the vehicle, and a throttle valve opening detection means for detecting that the throttle valve is in a fully closed state. When the output of the vehicle speed detecting means is below a predetermined value, the output of the vehicle speed detecting means is within a predetermined range, and the throttle valve opening detecting means detects that the throttle valve is fully closed, the output of the rotation speed detecting means and An electronic control device for an internal combustion engine, comprising control means for feedback controlling ignition timing of the internal combustion engine according to a deviation from a target rotation speed. (2) The control means calculates an average value of the rotation speed of the internal combustion engine at every predetermined time period or every predetermined internal combustion engine crank angle,
The electronic control device for an internal combustion engine according to claim 1, wherein this value is set as the target rotation speed. (3) The control means determines the transmission gear ratio from the ratio of the output of the vehicle speed detection means and the output of the rotation speed detection means,
Claims 1 and 2 are characterized in that the ignition timing feedback control gain is changed according to this value.
An electronic control device for an internal combustion engine as described in . (4) The control means is configured such that the output of the rotation speed detection means and the output of the throttle valve opening detection means of the internal combustion engine exceed a predetermined value;
4. The electronic control device for an internal combustion engine according to claim 1, wherein the ignition timing feedback control is stopped when it is determined that the vehicle is in an accelerating state.