JPH01358A - Internal combustion engine ignition timing control device - 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] <Industrial application field> The present invention relates to an ignition timing control device for an internal combustion engine.

<Prior Art> As a conventional ignition timing control device for an internal combustion engine, there is one disclosed in, for example, Japanese Patent Laid-Open No. 184967/1983.

In this type of engine, the target ignition timing is set based on the engine operating state, and ignition is performed by cutting off the power to the ignition coil at the target ignition timing (crank angle position) detected by the crank angle sensor. There is.

Incidentally, the crank angle sensor outputs a reference signal at each predetermined crank angle position for each cylinder, and also outputs a unit angle signal at each minute crank angle (for example, 1 degree), which corresponds to the target ignition timing. It is possible to accurately detect the crank angle position.

<Problems to be Solved by the Invention> However, the above-mentioned crank angle sensor is expensive, and the control using it is complicated. A system has been proposed in which the engine rotational speed is detected by

When performing ignition control in this device, the target ignition timing is set based on the operating state including the engine speed detected as described above, and the time from outputting the reference signal to reaching the target ignition timing is calculated. Then, while measuring the time from outputting the reference signal to reaching the target ignition timing using a timer, energization to the ignition coil is started a predetermined time before the target ignition timing, which is set according to the engine operating status, and the target ignition timing is reached. It is conceivable to ignite the ignition coil by cutting off the power to the ignition coil when the time is reached.

However, when the engine speed is steady or close to steady, the above method can perform sufficiently good ignition timing control, but when the engine speed is starting or starting, the engine speed increases, so the above method does not control the ignition timing. This also causes a large deviation in the energization time, making it impossible to perform good ignition timing control.

For example, as shown in Fig. 6, in a case where the reference signal is generated at a position of 10° before top dead center (BTDC) of each cylinder (100' f7), the engine speed is 2.
, when the ignition timing reaches 20 minutes before the compression top dead center of the specified cylinder.
Suppose it is set to °. In this case, when the latest reference signal is input, energization is started a predetermined time before the ignition timing according to the engine speed detected based on the elapsed time since the previous reference signal was manually input, and the predetermined time elapses. Try cutting off the power to the rear ci. However, in reality, when the next reference signal is input due to a sudden increase in rotation speed,
In some cases, ignition is not performed, and in this case, it is unavoidable to cut off the current and ignite at the same time as the reference signal is input, but the energization time may not be sufficient and a misfire may occur. By the way, if the rotation increases by 20 Orpm while the rotation speed is detected every two rotations due to acceleration, etc.,
At low rotations, for example, when changing from 400 rpm to 6 degrees orpm, an ignition timing shift of 90 degrees occurs, whereas at high rotations, for example, when changing from 3200 rpm to 3400 rpm, the ignition timing shifts by 11.
25°, and the lower the rotation, the more likely the above problem will occur.

The present invention has been developed in view of these conventional problems, and uses a simple control system that sets the engine speed and ignition timing using only a reference signal.

It is an object of the present invention to provide an ignition timing control device for an internal combustion engine, which can secure sufficient energization time and perform ignition even when the engine speed changes rapidly such as during startup.

Means for Solving the Problems> For this reason, the present invention, as shown in FIG. An engine rotation speed detection means that detects the engine rotation speed based on the period between measured signal outputs, and a target ignition timing at which power to the ignition coil is cut off according to the engine operating state including the engine rotation speed. target ignition timing setting means; energization time setting means for increasing and setting the energization time to the ignition coil in a low rotational speed region below a predetermined value; and target ignition timing and energization time set as a period between reference signal outputs. energization start timing setting means for setting the energization start time to the ignition coil based on the above, and a time signal from the timing means to start energization to the ignition coil at the set energization start time;
The configuration includes an ignition signal output means for outputting an ignition signal to cut off the energization at the earlier of the lapse of the set energization time or the input of the reference signal.

<Operation> The engine rotation speed is detected by the engine rotation speed detecting means from the period of each reference signal output, and the target ignition timing and the energization time to the ignition coil are determined respectively based on the operating state including the engine rotation speed, etc. time jtJ] setting means 1 is set by the energization time setting means.

In addition, the energization start timing setting means starts energizing the ignition coil based on the period between reference signal outputs and the set target point timing 1 energization time, and either when the energization time elapses or when the reference signal is input. An ignition signal to cut off the current is output at an early stage.

Here, since the energization time is set to a large value in a low engine speed region where the amount of change in engine speed is large, a sufficient energization time can be secured and ignition can be performed.

<Example> An example of the present invention will be described below based on FIGS. 2 to 5.

In FIG. 2, an air flow meter 3 for detecting the intake air flow rate and a throttle sensor 5 for detecting the opening degree of the intake throttle valve 4 are provided in the intake passage 2 of the engine 1, and these detection signals are input to the control device 6. has been done. Further, the engine 1 is provided with a fuel injection valve 7 for each cylinder. These fuel injection valves 7 are opened by an injection pulse signal corresponding to the fuel injection amount from the control device 6, and fuel is injected and supplied to the engine 1.

Further, each cylinder of the engine 1 is provided with an ignition plug 8.

A high voltage generated by an ignition coil 9 is sequentially applied to these ignition plugs 8 via a distributor 1O, thereby igniting a spark to ignite and burn the air-fuel mixture. Here, the generation timing of the high voltage is controlled via the power transistor 11. The ignition timing is controlled by controlling the ON/OFF timing of the power transistor 11 using an ignition signal from the control device 6.

Further, a reference signal generator 12 is attached to the crankshaft (not shown) as a reference signal output means for outputting a reference signal to a predetermined crank angle position of each cylinder. Specifically, in the case of a 4-cylinder engine, a signal disk is provided with a protrusion (BTDClooo) at every 90° crank angle, and a signal disk is provided close to the outer periphery of the signal disk and outputs a pulse (reference signal) each time the protrusion passes. It consists of a pickup.

The reference signal is input to the control device 6, and based on the reference signal, the engine rotation speed and the like are detected and the ignition timing is set.

Next, the ignition timing control routine by the control device 6 will be explained according to the flowchart shown in FIG.

In step 1 (denoted as S in the diagram), when a reference signal is input, ignition is performed once every two revolutions of each cylinder, so the number of inputs of the reference signal is counted up, and the ignition is performed twice as determined in step 2. Each time, in step 3, the count value is reset to O, and the process proceeds to step 4.

In step 4, the period T0 from the previous reference signal input to the current input is calculated from the value of the timer T reset by the step 12, which will be described later, and the engine rotation speed N is calculated as a value proportional to its reciprocal. . This step 4 corresponds to the engine rotation speed detection means.

In step 5, the battery voltage v! Enter l.

In step 6, the engine speed N and the load (e.g. basic injection wTy = K-o, / N; Q is the intake air flow 4
3. K is a constant) based on the target ignition timing ADV (
In addition to setting the advance angle (4il) before compression top dead center, the ignition coil lO is set based on the battery voltage ■8 and the engine speed N.
The energization time T'n, , 4 is set.

This step 6 corresponds to target ignition timing setting means and energization time setting means.

Here, regarding the energization time (dwell time) To, the lower the battery voltage (8), the more time is required to store ignition energy, so the basic energization time (see Figure 4), which is set to a large value, is set at the time of departure or startup. In the corresponding low rotational speed region, the rotational speed increases rapidly, so the energization time is multiplied by a correction coefficient set larger than 1 to increase the energization time as shown in FIG.

In step 7, energization start timing (time after reference signal input) T8. is calculated using the following formula.

Here, T indicates the amount of advance before compression top dead center at the time when the reference signal is generated.

This step 7 corresponds to the energization start timing setting means.

In step 8, it is determined whether the elapsed time T after the reference signal input by the timer matches the energization start time calculated in step 7. If it is determined that they match, the process proceeds to step 9 and the ignition coil 9 is energized. At the same time, a flag F indicating the start of energization is set to 1.

In step 10, it is determined whether the elapsed time T matches the time that has elapsed from the energization start time TST to the set energization time TDW, and when they match, the process proceeds to step 11 and the energization to the ignition coil 9 is cut off. . As a result, as described above, a high voltage is applied to the spark plug 8 of the corresponding cylinder, and ignition is performed.

Further, a flag F is reset to O to indicate a state in which energization is stopped.

On the other hand, if the determination in step 2 is No, step 1
After the timer T is reset to O in order to start measuring the elapsed time in step 2, the process proceeds to step 13, where it is determined whether the value of the flag F indicating the energization state is 1 or not.

If it is (2), the current is still being energized and ignition has not been performed by the time the current reference signal is manually input, so the process proceeds to step 11, where the current is immediately cut off and the corresponding cylinder is ignited.

When the flag is O, ignition has ended, so this routine ends.

In this way, when the engine speed suddenly increases during starting or starting, the energization time can be increased in advance to bring the energization start time earlier, and even if the ignition is started at the same time as the reference signal is input, sufficient energization can be ensured. Since time can be secured, misfires can be prevented from occurring.

When the engine speed reaches its upper limit and the fluctuation rate of the engine speed decreases, the discrepancy between the target ignition timing and the actual ignition timing becomes smaller. This allows for good ignition timing control.

<Effects of the Invention> As explained above, according to the present invention, the engine speed and target ignition timing are set using only a reference signal, which is a simple method that requires low cost. Even when the rotation speed detection accuracy is reduced due to a large change in the number of rotations, it is possible to ensure sufficient time for energizing the ignition coil and prevent misfires from occurring.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a flowchart showing a control routine of the above embodiment, and Fig. 4 is used for the control of the above. FIG. 5 is a characteristic diagram of the basic energization time, FIG. 5 is a characteristic diagram of the correction coefficient, and FIG. 6 is a characteristic diagram of the 11Jl control at the time of ignition of a conventional example. 1... Engine 3... Air flow meter 6...
・Control device 8...Ignition plug 9...Ignition coil Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima Figure 2

Claims (1)

[Scope of Claims] A reference signal output means for outputting a reference signal at each predetermined crank angle position; and an engine for detecting the engine rotation speed based on a period between signal outputs measured by a clock means each time the reference signal is output. a rotation speed detection means; a target ignition timing setting means for setting a target ignition timing at which the energization to the ignition coil is cut off in accordance with the engine operating state including the engine rotation speed; An energization time setting means that sets the energization time by making an increase correction in the rotation speed region, and an energization start timing setting that sets the energization start time to the ignition coil based on the cycle between reference signal outputs, the set target ignition timing, and the energization time. and a timing signal from the timing means to start energizing the ignition coil at the set energization start time,
An ignition timing control device for an internal combustion engine, comprising: an ignition signal output means for outputting an ignition signal to cut off energization when a set energization time elapses or when a reference signal is input, whichever comes first. .