JPS60159372A - Ignition-timing control for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the generation of knocking after a throttle valve is sharply opened, by delaying the ignition advance on the delay-angle side by the amount increased in accordance with the magnitude of the engine acceleration during a prescribed period from the time point when the throttle valve is opened from an idle position. CONSTITUTION:When a throttle valve 10 is opened from idle position in engine operation, an idle swithc in a throttle sensor 24 is turned OFF, and it is judged in a control circuit 20 that the number of times of ignition at the change time point is within N times of ignition ro not (the period up to the stabilization of the pressure in a suction pipe after the opening of the throttle valve). If the judgement is YES, that rapid accelerarion or not is judged on the basis of the variation rate of the opening degree of the throttle valve, and in case of rapid acceleration, the amount QR of delay angle is set to a prescribed value thetaA, and in case of slow acceleration, the amount thetaR of delay is set to a prescribed value thetaB (<thetaA). Then the idle ignition advance thetaIDL is compared with the ignitio advance obtained by correcting the fundamental ingnition advance read-out from a memroy, and if thetaIDL<theta, an ignitor 26 is controlled with the value obtained through the subtraction of thetaR from thetaIDL, as the final ignition advance.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an ignition timing control method for an internal combustion engine, and particularly to a method for controlling ignition timing based on a basic ignition advance angle when a throttle valve is opened. The present invention relates to an ignition timing control method for an internal combustion engine that controls ignition timing using an idle ignition advance angle when a throttle valve is in an idle position.

[Background of the invention]

Conventionally, engine load (intake pipe pressure or engine 1 rotation ab
The basic ignition advance angle θBA8 is determined by the intake air amount) and the engine speed.
1+, correct the basic ignition advance angle θBASE using intake air temperature, engine cooling water temperature, throttle valve opening speed, etc. to determine the ignition advance angle θ, and control the igniter on/off so that the ignition is ignited at this ignition advance angle θ. Timing control methods are known. In this ignition timing control method, in order to stabilize the idle speed, the idle ignition advance angle θIDL is determined according to the engine speed and the on/off state of the compressor of the near conditioner, and when the throttle valve is at the idle position, that is, the throttle valve is in a fully closed state, the above idle ignition advance angle θID, which is unrelated to the basic ignition advance angle θBABK,
The ignition timing is controlled by L.

However, under operating conditions such as racing where the throttle valve is suddenly opened from the idle position, there is a delay in suctioning the amount of air immediately after the sudden opening, and the throttle valve is fully closed even though it is open. The same operating conditions as in the state continue for a predetermined period of time.

Therefore, the intake pipe pressure changes as shown by line A in the first diagram, and the basic ignition advance angle θmABg determined by the intake pipe pressure and engine speed changes as shown by line B. Therefore, there is a problem in that immediately after the throttle valve is suddenly opened, the ignition timing is overadvanced and knocking occurs even though the engine is under the same operating condition as idling. to solve this problem,
As shown by line c1D in Figure 1, from the time when the throttle valve is opened from the closed state, for a predetermined period of time or a predetermined number of ignitions, the idle ignition advance angle θIDL or the ignition advance angle θ on the retard side of the idle ignition advance angle θ . However, when the intake pipe pressure becomes stable, the ignition advance angle is advanced more than the required ignition advance angle, causing the same problem as above in that knocking occurs.

The above problem similarly occurs in an engine in which the basic ignition advance angle is determined by the intake air amount and the engine speed, and the intake air amount is detected using an air 70-meter upstream of the throttle valve.

In addition, in order to solve the above problem, the applicant has proposed that for a predetermined period from the time when one throttle valve is opened from the idle position, either the ignition advance angle based on the basic ignition advance angle or the idle ignition advance angle is selected. A method of controlling the ignition timing using the smaller ignition advance angle (Japanese Patent Application No. 186637/1982) has been filed, but there is a risk that knocking may occur when the engine suddenly accelerates.

[Purpose of the invention]

The present invention has been made to solve the above problems, and by controlling the ignition timing to an optimal value, knocking does not occur immediately after the throttle valve is suddenly opened from a fully closed state, such as during racing or early acceleration. An object of the present invention is to provide an ignition timing control method for an internal combustion engine.

[Structure of the invention]

In order to achieve the above object, the present invention controls the ignition timing with the ignition advance angle based on the basic ignition advance angle determined by the engine load and engine speed when the throttle valve is open, and also controls the ignition timing when the throttle valve is open. In an ignition timing control method for an internal combustion engine in which the ignition timing is controlled by the idle ignition advance angle at the idle position, the ignition timing is controlled based on the basic ignition advance angle for a predetermined period from the time the throttle valve is opened from the idle position. The ignition timing is controlled by retarding either the ignition advance angle or the idle ignition advance angle by an amount that is increased in accordance with the magnitude of engine acceleration.

The above predetermined period is determined by time or the number of ignitions.

According to the present invention, the ignition advance angle on the retarded side of either the ignition advance angle based on the basic ignition advance angle or the idle ignition advance angle is used as a reference, and this reference ignition advance angle is adjusted to the magnitude of the engine acceleration. Since the ignition timing is controlled by retarding the ignition timing by an amount increased accordingly, after the throttle valve is opened from the idle position, the idle ignition advance is retarded until air is sucked in according to the opening degree of the throttle valve. The ignition is ignited with an ignition advance that is retarded according to the acceleration, and after air is taken in according to the throttle valve opening, the ignition is advanced based on the basic ignition advance until the intake pipe pressure or intake air amount stabilizes. The engine is ignited at an advanced ignition angle that is retarded according to the engine acceleration.

〔Effect of the invention〕

Therefore, according to the present invention, it is possible to prevent knocking from occurring until the intake pipe pressure or intake air amount stabilizes after the throttle valve is suddenly opened from the idle position.
A unique effect can be obtained.

[Embodiments of the invention]

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

FIG. 2 shows an example of an ignition timing control system to which the present invention is applied. Crank angle sensors 16 and 18, which each consist of a signal rotor fixed to a distributor shaft and a pickup fixed to a distributor housing, are attached to a distributor 14 of a 4-cycle 6-cylinder internal combustion engine (K/JIN). . The crank angle sensor 16 is for cylinder discrimination, and generates K1 pulses every time the distributor shaft makes one revolution, that is, every two revolutions of the crankshaft (every 720° C.A.). This pulse generation position is, for example, the top dead center (TDC) of the first cylinder #1. The crank angle sensor 18 generates 24 nopulses per revolution of the distributor shaft, thus one pulse every 30°C.

A throttle valve 10 is arranged in the intake passage 22, and a throttle sensor 24 is attached to the throttle valve 10. Further, a pressure sensor 12 for detecting intake pipe absolute pressure is installed so as to protrude into the surge tank on the downstream side of the throttle valve 1°.

The pressure sensor 2, crank angle sensor 16, 18, and throttle sensor 24 are connected to a control circuit 20 made up of a microcomputer, and electrical signals generated by each sensor and switch are input to the control circuit 20. On the other hand, the control circuit 20 outputs an ignition signal to the igniter 26, and the high current generated by the igniter 26 is distributed by the distributor 14 and sequentially sent to the ignition bladder 28 attached to each cylinder.

As shown in FIG. 3, the above-mentioned throttle sensor 24 is
A contactor 24A fixed to the shaft of the throttle valve 10 and rotating together with the throttle valve 10, and a resistor 24B having one end grounded and the other end connected to a power source and arranged so as to be in contact with the contactor 24A. It is composed of the following. This contactor is connected to the control circuit 20 for two days. Further, an idle switch 24C is provided, one end of which is connected to the power supply and the other end of which is connected to the control circuit 20. The idle switch 24C is turned on when the throttle valve is in the idle position (fully closed) and turned off when the throttle valve is opened.

As a result of the throttle sensor 24 being configured as described above, a high level signal is input to the control circuit 2o via the idle switch 24C during idling, and
A voltage corresponding to the opening degree of the throttle valve is input to the control circuit 20 .

Note that various sensors such as an intake air temperature sensor for detecting operating state parameters are usually attached to the engine, and the control circuit 20 also controls the fuel injection valves 29, etc., but since these are not directly related to the present invention, they will be described below. All of these will be omitted in the explanation.

FIG. 4 is a block diagram showing an example of the configuration of the control circuit 20 shown in FIG. 2. The intake pipe pressure signal from the pressure sensor 12 and the output voltage from the contact 24A of the throttle sensor 24 are sent to an analog multiplexer 32 via a buffer 30.
microprocessing unit (MP).
U) are sequentially selected according to instructions from 62 and A/
After being converted into a digital signal by the D converter 34, it is taken into the microcomputer via the input/output port 36.

The pulse every 720°C from the crank angle sensor 16 is
The signal is input to the interrupt request signal forming circuit 40 via the back 738. In addition, 30°C A from the crank angle sensor 18
Each pulse is input to an interrupt request signal forming circuit 40 and an engine rotation speed signal forming circuit 44 via a buffer 42. The interrupt request signal forming circuit 40 operates at 720°C
Various interrupt request signals for each predetermined crank angle are formed from the pulses at every 30° C. and every 30° C., and these interrupt request signals are input into the microcomputer via the input/output port 46. The engine rotational speed signal forming circuit 44 includes 3
011: Engine rotation speed N from the pulse period for each A. Completely form two communication signals representing .

This binary signal is sent into the microcomputer via the input/output port 46.

μμ The on/off signal 1g from the idle switch 24 is taken into the microcomputer via the input/output port 46tl. On the other hand, when the ignition signal No. 16 is outputted from the MPU 62 to the drive circuit 60 via the input/output boat 46, this is converted into a drive signal to energize the igniter 26, and ignition timing control is performed according to the ignition signal.

The microcomputer has input/output ports 36 and 46
, MPU 62, random access memory (RAM) 64
, a read-only memory (ROM) 66, a clock generation circuit (not shown), a bus 68 connecting these, and the like, and executes various processes according to control programs stored in the ROM 66. Also, R
A map of the basic ignition advance angle θBASH determined based on the intake pipe pressure and the engine speed is stored in the OM in advance.

In addition, when using an air flow meter that detects the intake air amount on the upstream side of the throttle valve instead of the pressure sensor 2, the basic ignition value determined by the intake air amount per engine rotation and the engine rotation speed is stored in the ROM. A map of advance angle θB8S8 is stored.

Next, a processing routine according to an embodiment of the present invention will be explained with reference to the drawings. The routine shown in FIG. 5 is executed by interrupt processing at every predetermined crank angle.
It is determined whether the throttle valve is open by determining whether the idle switch is off or not.

When the idle switch is on, that is, when the throttle valve is in the idle position, the idle ignition advance angle θIDL is set as the final ignition advance angle θFINAL in step 101, and the igniter is set to ignite at the final ignition advance angle θFINAL in the next routine. Control.

When the idle switch is off, that is, when the throttle valve is open, it is determined in step 102 whether the number of ignitions is within N ignitions from the time the idle switch changes from on to off.

This N ignition is a period from when the throttle valve is opened from the idle position until the intake pipe pressure becomes stable, and is a constant determined depending on the engine.

When it is determined in step 102 that the number of ignitions is within N ignitions, in step 103 the throttle opening T is determined by the output voltage of the contactor 24A of the throttle sensor 24.
By determining whether the rate of change ΔTHA of HA is greater than or equal to a predetermined value A, it is also determined whether the engine is rapidly accelerating. When it is determined that the engine is rapidly accelerating, the retardation amount θR is set to a predetermined value θA in step 104. On the other hand, when the engine is not rapidly accelerating, that is, when the engine is slowly accelerating, the retardation amount θR is set to a predetermined value θB (however, θB
A). Note that the predetermined values θA and θB are values that are determined depending on each engine and are a retard cover for preventing the occurrence of knocking during acceleration.

In the next step 106, the idle ignition advance angle and the ROM
Basic ignition advance angle θBASi determined by interpolation from the map of
The ignition advance angle θ obtained by correcting l is compared. When the idle ignition advance angle θIDL is smaller than the ignition advance angle θ, in step 107, the value obtained by subtracting the retard amount θR from the idle ignition advance angle θIDL is set as the final ignition advance angle θFINAL, and the ignition advance angle θ is set as the idle ignition advance angle θIDL. In the following cases, the value obtained by subtracting the retard amount θR from the ignition advance angle θ is set as the final ignition advance angle θFINAL in step 108, and the igniter is controlled so as to be ignited at the final ignition advance angle θFINAL in the next routine.

As a result of the above, from the time when the idle switch changes from on to off, until 9N ignition elapses, the ignition advance angle on the retard side of either the idle ignition advance angle θIDL or the off-idle ignition advance angle θ is accelerated. The ignition timing is controlled by the ignition advance retarded by the retard amount θ, which is increased according to the magnitude of the ignition timing.

If it is determined in step 102 that N ignitions have elapsed since the time when the idle switch changed from on to off, in step 109 the ignition advance angle θ based on the basic ignition advance angle is set as the final ignition advance angle θFINAL, and the final ignition advance is set as the final ignition advance angle θFINAL. angle θ
Control the igniter so that it is ignited at FINAL.

Final ignition advance angle θFINAL when controlled as above
Figure 6 shows the changes in . As can be understood from the figure, the final ignition angle θFINAL becomes θIDL - θR after the throttle valve is opened from the idle position until air is taken in according to the throttle valve opening. After the air according to the amount of air is inhaled, the pressure becomes θ-θR until the intake pipe pressure stabilizes, and then becomes θ.

Note that in the above, the period from the time when the throttle valve is opened from the idle position until the intake pipe pressure stabilizes is determined by the number of ignitions, but it may be determined by time.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing changes in intake pipe pressure and conventional ignition advance angle, Fig. 2 is a schematic diagram showing an ignition timing control system to which the present invention is applied, and Fig. 3 shows details of the throttle sensor. 4 is a block diagram showing an example of the control circuit of FIG. 2, FIG. 5 is a flowchart showing a processing routine of an embodiment of the present invention, and FIG. 6 is a diagram showing the final ignition advance angle in the above embodiment. It is a line diagram showing a change. 12...Pressure sensor, 24...Throttle sensor, 28...Spark plug. Agent Tatsuyuki Unuma (1 person) mile! 0 1K3 Zumei 2

Claims (1)

[Claims] (1) When the throttle valve is open, the ignition timing is controlled by the ignition advance angle based on the basic ignition advance angle determined by the engine load and engine speed, and when the throttle valve is at the idle position, the ignition timing is controlled by the ignition advance angle based on the basic ignition advance angle determined by the engine load and engine speed. In an internal combustion engine ignition timing control method that controls the ignition timing based on the ignition angle, the ignition advance angle based on the basic ignition advance angle and the idle ignition advance angle are determined for a predetermined period from the time the throttle valve is opened from the idle position. An ignition timing control method for an internal combustion engine, characterized in that the ignition timing is controlled by retarding either one of the ignition advance angles on the retard side by an amount that is increased in accordance with the magnitude of engine acceleration.