JP2596110B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an ignition type engine (internal combustion engine) in a gasoline engine.

[Prior Art] Conventionally, ignition timing control of a gasoline engine has been performed, for example, as follows. That is, the operating state of the engine is detected from a flow rate sensor for detecting the intake air amount of the engine and an engine speed sensor for detecting the engine speed, and the intake air amount A is determined based on the detection results from these sensors. The ignition timing information is obtained from a two-dimensional map having an advanced value (ignition timing information) determined by the volume efficiency Ev (A / N) obtained by dividing by the number N and the engine speed N, and the ignition timing information is appropriately determined. Correction,
The ignition timing of the engine is controlled by operating the ignition means (ignition plug, ignition coil, etc.) based on the ignition timing information obtained in this manner.

By the way, the mechanism of flying a spark by the spark plug is as follows. First, the energizing current i (A) to the ignition coil is represented by E (V) as the battery voltage, R (Ω) and L (H) as the DC resistance and inductance of the primary coil of the ignition coil, respectively, and the time from the start of energization. Is t (sec), i = E / R {1-exp (-Rt / L)} (1) That is, as shown in FIG. 7, by turning on the power transistor 10 to the ignition coil 9, a primary current flows according to the above equation (1),
Energy is stored in the ignition coil 9. After that, when the power transistor 10 is turned off, 1
The secondary current is interrupted, and a large voltage is generated in the secondary coil of the ignition coil 9. This secondary voltage causes a spark to fly to the ignition plug 7 connected to the secondary coil of the secondary coil 9 of the ignition coil 9. is there. At this time, the discharge arc continues until the secondary discharge energy is exhausted.

In FIG. 7, reference numeral 14 denotes a battery, and 15 denotes a key switch.

Further, the primary current characteristics and the secondary discharge energy characteristics of the ignition coil are as shown in FIGS. 8 (a) and 8 (b).

[Problems to be Solved by the Invention] However, in the conventional ignition timing control device for an engine, particularly in a multi-cylinder high-speed engine, if ignition is performed using one ignition coil, the frequency of ignition increases, and Such a problem arises.

(1) It is difficult to secure the time for energizing the coil, so that the primary cutoff current decreases as shown in FIG. 9A, and the secondary voltage also decreases. For this reason, fireworks are less likely to fly with the spark plug.

(2) For the reason of the above (1), ignition is performed,
Although the secondary discharge energy was not sufficiently discharged, the arc was cut off in the middle as shown in FIG.
Since it is necessary to immediately start the energization, the arc time is shortened, and ignition may fail.

The present invention is intended to solve such a problem. In a multi-cylinder high-speed engine, when ignition is performed using a single ignition coil, an arc time or an energization start time according to an engine load state. It is an object of the present invention to provide an ignition timing control device for an engine, which can realize ignition without failure by appropriately giving priority to.

[Means for Solving the Problems] For this reason, the engine ignition timing control device of the present invention
An ignition portion is arranged toward the combustion chamber of the internal combustion engine, and an ignition plug connected to the secondary side of the ignition coil is connected to the ignition coil. The ignition coil is connected to the primary side of the ignition coil to turn on and off, thereby energizing the ignition coil. Switch means for starting discharge, and control means for controlling the on / off timing of the switch means, wherein the control means sets an arc time according to the operating state of the internal combustion engine, An energization start time setting means for setting an energization start time according to an operation state of the internal combustion engine; and an arc time set by the arc time setting means when the internal combustion engine is operating at a load lower than a required load state. When the internal combustion engine is operating with a load higher than the required load state, the power supply start time set by the power supply start time setting means is given priority. Is characterized in that it is configured to include a determination means for controlling said switching means so as to previously be.

[Operation] In the above-described ignition timing control device for an engine of the present invention, when the internal combustion engine is operating at a load lower than the required load state, the arc time set by the arc time setting means is given priority, and the internal combustion engine is activated. In an operation state of a load higher than the required load state, the switch means is controlled so that the power supply start time set by the power supply start time setting means is prioritized.

[Embodiment] Hereinafter, an engine ignition timing control apparatus as an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a control block diagram thereof, and FIG. FIG. 3, FIG. 3 is a flow chart for explaining the control procedure, FIG. 4 is a graph for explaining the minimum arc time with respect to the engine load, FIG. 5 is a table map for storing the ignition advance angle, and FIG. 6 is a timing chart for explaining an operation.

The vehicle-mounted gasoline engine system controlled by the present apparatus is as shown in FIG. 2. In FIG. 2, the gasoline engine E (hereinafter simply referred to as engine E) is configured as an in-line four-cylinder engine. The engine E has an intake passage 1 and an exhaust passage 2 that communicate with the combustion chamber of each cylinder. The communication between the intake passage 1 and the combustion chamber is controlled by an intake valve, and the exhaust passage 2 and the combustion chamber communicate with each other. Are controlled by an exhaust valve.

In addition, an air cleaner is provided in the intake passage 1 in order from the upstream side.
3, a throttle valve 4 and an electromagnetic fuel injection valve (injector) 5 are provided. In the exhaust passage 2, a catalytic converter (three-way catalyst) and a muffler (silencer) for purifying exhaust gas (not shown) are arranged in order from the upstream side. Device 6 is provided.

Note that the injectors 5 are provided in the intake manifold portion by the number of cylinders. Now, since the engine E of the present embodiment is an in-line four-cylinder engine, four injectors 5 are provided. That is, it can be said that the engine is a so-called multipoint fuel injection (MPI) type engine.

The throttle valve 4 is connected to an accelerator pedal via a wire cable, so that the opening changes according to the amount of depression of the accelerator pedal.

Further, in each cylinder, a spark plug 7 in which an ignition section is arranged toward its combustion chamber (in FIG. 2, the spark plug 7 should be drawn near the engine combustion chamber, but due to space limitations, Each spark plug 7 is connected to a distributor 8, which is connected to an ignition coil 9. A high voltage is generated on the secondary coil side of the ignition coil 9 by the OFF operation of the power transistor (switch means) 10 connected in the primary coil order of the ignition coil 9, and the four ignitions connected to the distributor 8 Either of the plugs 7 sparks (ignites). The ignition coil 9 starts energization (charging) by the ON operation of the power transistor 10.

With such a configuration, the air sucked through the air cleaner 3 according to the opening degree of the throttle valve 4 is mixed with the fuel from the injector 5 at the intake manifold portion so as to have an appropriate air-fuel ratio, and the ignition plug 7 is discharged in the combustion chamber. By igniting at the appropriate timing, it is burned,
After generating the engine torque, the air-fuel mixture is discharged as exhaust gas into the exhaust passage 3, where the catalytic converter purifies the three harmful components of CO, HC, and NOx in the exhaust gas, and then is muffled by the muffler 6 to release the air. It is designed to be released to the side.

Incidentally, an air flow sensor 11 and a crank position sensor 12 are provided to control the ignition timing of the engine E.

Here, the air flow sensor 11 is a volume flow meter that is provided in an air cleaner provided portion of the intake passage 1 and detects the amount of intake air from Karman vortex information. The crank position sensor 12 detects, for example, the 75 ° BTDC position of each cylinder. This allows the engine speed N to be detected. Therefore, since the crank position sensor 12 also functions as an engine speed sensor, the crank position sensor 12 may be hereinafter referred to as an engine speed sensor as needed.

Actually, since various controls such as fuel supply control are performed on the engine E in addition to the ignition timing control,
Although not shown, various sensors are provided. That is,
Intake air temperature sensor for detecting intake air temperature, atmospheric pressure sensor for detecting atmospheric pressure, potentiometer type throttle sensor for detecting opening of throttle valve 4, idle switch for detecting idling state, oxygen concentration in exhaust gas (O ₂ Oxygen concentration sensor (O ₂ sensor) for detecting the concentration of water, and a water temperature sensor for detecting the temperature of the engine cooling water.

And the detection signal from each of the above sensors is CPU, RAM,
The data is input to an electronic control unit (ECU) 13 including a ROM and a required interface circuit.
Although not shown, a voltage signal from a battery sensor that detects the voltage of the battery 14 and a signal from an ignition switch (key switch) 15 are also input to the ECU 13.

By the way, since the ECU 13 has a function of control means for controlling the ON / OFF timing of the power transistor 10, an ignition timing control signal is output from the ECU 13 to the power transistor 10 via the ignition driver 16, and furthermore, the ignition is performed. The four spark plugs 7 are sequentially sparked from the coil 9 via the distributor 8.

The ignition driver 16 has first and second one-shot multivibrators 17, 18 and a flip-flop 19, and the first one-shot multivibrator 17 is triggered by a 75 ° BTDC position signal from the crank position sensor 12. When the power transistor 10 is to be turned off (ignition start timing), a pulse signal is output. The second one-shot multivibrator 18 includes a first one-shot multivibrator 17.
Is triggered by the output of (1), and issues a pulse signal when the power transistor 10 should be turned on (at the start of energization).
The output from the first one-shot multivibrator 17 is input to the reset terminal of the flip-flop 19, and the output from the second one-shot multivibrator 18 is input to the set terminal of the flip-flop 19.
Then, the output of the flip-flop 19 is input to the control terminal (base terminal) of the power transistor 10.

The times α and β from when the trigger signal is input to the one-shot multivibrators 17 and 18 until the pulse signal is output are set by signals from the ECU 13, respectively.

When the flip-flop 19 is reset, the power transistor 10 is turned off. When the flip-flop 19 is set, the power transistor 10 is turned on. Therefore, the first one-shot multivibrator 17 determines the ignition timing. Then, the second one-shot multivibrator 18 determines the ignition coil energization timing.

Further, to determine the above times α and β, the ECU 13
Has functions of an ignition advance table 20, an ignition timing setting unit 21, an energization start timing setting unit 22, an arc time setting unit 23, and a determination unit 24, as shown in FIG.

Here, as shown in FIG. 5, the ignition right angle table 20 is based on A / N (volume efficiency obtained by dividing the intake air amount A by the engine speed N) having the engine load information and the engine speed N. The ignition timing setting means 21 has a two-dimensional memory for determining each required ignition advance SAij (hereinafter referred to as SA when it is not necessary to distinguish the SAij separately). The above time α is calculated and set from SA, 75 か ら BTDC position signal cycle T.

The energization start time setting means 22 determines the 75 ° BTDC position signal period T
The time β corresponding to the arc start time is calculated and set by subtracting the optimum coil energizing time (dwell time) DWELL from the above. The arc time setting means 23 has the engine load information as shown in FIG. It has a memory or arithmetic means for determining the required arc time ARC from A / N.

The determination means 24 sets β = ARC if the value β set by the energization start time setting means 22 is smaller than the value ARC set by the arc time setting means 23, as shown in FIG. As can be seen from the ARC-A / N characteristics, the value of ARC is larger in the low engine load state, so that the determination means 24 determines whether the engine E is operating under a load lower than the desired load state. The set arc time ARC is prioritized, and when the engine E is in an operation state with a load higher than the required load state, a result is given in which the energization start timing information β set by the energization start timing setting means 22 is prioritized.

As described above, it is better to give priority to the arc time ARC when the engine E is in the low load operation state and give priority to the energization start timing information β when the engine E is in the high load operation state for the following reasons. . In other words, when the engine is in a low-load operation state, the internal EGR (the ratio of the previous exhaust gas that is not discharged from the combustion chamber and carried over to the next cycle) increases,
It is difficult to ignite. Therefore, in the low load operation state of the engine, it is better that the arc time is long, and the required plug voltage (the voltage required to cause insulation breakdown in the spark plug gap) increases as the air density increases. Therefore, in the high-load operation state of the engine, the plug request voltage should be set as high as possible by giving priority to the energization start timing information β.

Next, the control procedure for ignition will be described with reference to the flowchart shown in FIG. It should be noted that the routine shown in this flowchart operates every time a 75 ° BTDC position signal is input as an interrupt signal. First, step
At A1, the intake air amount is measured from the detection signal from the air flow sensor 11, and this is set as AIR. After that, step A
In steps 2 to A4, a 75 ° BTDC position signal period T is obtained using the 75 ° BTDC position signal from the crank position sensor 12, and the engine speed N is calculated based on the period T (step A).
Five).

Further, in step A6, A / N is obtained from the engine speed N obtained in step A5 and the intake air amount AIR obtained in step A1.

In this manner, when the current engine load information A / N and the engine speed N are detected, from these information,
The optimum ignition advance SA is found from the table shown in FIG. 5 (step A7).

After that, the ignition timing setting means 21 calculates α = ｛(75−SA)
By performing an operation of / 180｝ × T, the time α until the ignition is obtained (step A8).
Is set to the one-shot multivibrator 17.

On the other hand, in step A10, the energization start time setting means 22 calculates the maximum value of the arc time β from the T-DWELL by calculation, and in step A11, the arc time setting means 23 calculates the characteristic as shown in FIG. The arc time ARC is set from the figure.

Thereafter, the determination means 24 determines whether β <ARC, and if β <ARC, ARC is prioritized and β = ARC, otherwise β is used as it is (step
A12). Then, in the next step A13, β obtained in step A12 is set in the second one-shot multivibrator 18.

In this manner, the power transistor 10 is turned off at the timing α, a high voltage is generated on the secondary side of the ignition coil 9, the ignition plug 7 is ignited, and the power transistor 10 is turned on at the timing β. Then, the arc is extinguished and energization of the ignition coil 9 is started.

At this time, when the engine is rotating at a high speed such that the arc time and the secondary voltage of the ignition coil 9 have a trade-off relationship, the timing of β is determined when the engine E is in a low-load operation state (in this state, the intake density is low. However, in the operation state where the required voltage is not high, but it is difficult to ignite, the arc time ARC set by the arc time setting means 23 is prioritized in the operation state in which it is difficult to ignite. In the state where the intake density is high and the required voltage is high, but the ignition voltage is good, the energization start timing information β set by the energization start timing setting means 22 is prioritized. Is performed using a single ignition coil, it is possible to realize ignition without failure.

The 75 ° BTDC position signal, each output of the first and second one-shot multivibrators, and the output of the ignition coil
6 (a) to 6 (d) show the secondary coil currents respectively.
become that way.

In addition, the ECU 13 has a function of controlling the air-fuel ratio by controlling the fuel injection amount from the injector 4 and the like. In this embodiment, a known control method is adopted.

Further, the present invention does not use a distributor,
It goes without saying that the present invention can also be applied to a low-voltage distribution type ignition device in which distribution is performed to an ignition plug by switching operation of semiconductor switching elements.

It should be noted that the ignition timing control device for an internal combustion engine of the present invention can of course be applied to the ignition timing control of a multi-cylinder engine other than the four-cylinder engine.

[Effects of the Invention] As described above, according to the ignition timing control apparatus for an internal combustion engine of the present invention, when the internal combustion engine is operating at a load lower than the required load state, the arc set by the arc time setting means is set. When the internal combustion engine is operating under a load higher than the required load state, priority is given to time, and switch means such as a power transistor is controlled so as to give priority to the energization start time set by the energization start time setting means. Therefore, in a multi-cylinder high-rotation engine, there is an advantage that even if ignition is performed using one ignition coil, ignition without failure can be realized.

[Brief description of the drawings]

1 to 6 show an ignition timing control device for an internal combustion engine as an embodiment of the present invention. FIG. 1 is a control block diagram thereof, and FIG. 2 is an overall configuration diagram showing an engine system having the device. FIG. 3 is a flowchart for explaining the control procedure, FIG. 4 is a graph for explaining the minimum arc time with respect to the engine load, FIG. 5 is a table map for storing the ignition advance angle, and FIG. FIG. 7 is an electric circuit diagram for explaining a current flowing through the ignition coil, and FIG. 8 is a primary current characteristic and a secondary discharge energy characteristic of the ignition coil when the engine is running at a low speed. FIG. 9 is a diagram showing an ignition coil primary current characteristic and a secondary discharge energy characteristic at the time of high engine rotation. DESCRIPTION OF SYMBOLS 1 ... Intake passage, 2 ... Exhaust passage, 3 ... Air cleaner, 4 ... Throttle valve, 5 ... Solenoid valve (injector), 6 ... Muffler, 7 ... Spark plug, 8 ... Distributor, 9 ... ... Ignition coil, 10 ... Power transistor (switch means), 11 ... Air flow sensor (volume flow meter), 12 ... Crank position sensor (engine speed sensor), 13 ... Electronic control unit (EC
U), 14 ... battery, 15 ... ignition switch (key switch), 16 ... ignition driver, 17 ... first one-shot multivibrator, 18 ... second one-shot multivibrator, 19 ... flip-flop ,
20: ignition advance table, 21: ignition timing setting means, 22
... Energization start time setting means, 23... Arc time setting means, 24... Determination means, E.

Claims (1)

(57) [Claims] A spark plug connected to a secondary side of an ignition coil; and an ignition plug connected to a primary side of the ignition coil to turn on and off the ignition coil. And a control means for controlling the on / off timing of the switch means, wherein the control means sets an arc time in accordance with an operation state of the internal combustion engine. Time setting means, energization start time setting means for setting energization start timing according to the operation state of the internal combustion engine, and setting by the arc time setting means when the internal combustion engine is operating at a load lower than a required load state. When the internal combustion engine is in an operation state with a load higher than the required load state, priority is given to the set arc time, and the communication time set by the energization start time setting means is set. Start time and characterized in that it is configured to include a determination means for controlling said switching means so as to prioritize, ignition timing control apparatus for an internal combustion engine.