JPS6410658B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for a four-cylinder internal combustion engine.

Conventionally, a centrifugal advance mechanism and a vacuum advance mechanism built into a power distributor mechanically coupled to the internal combustion engine have been used to control the ignition timing of a four-cylinder internal combustion engine. However, with such mechanical ignition timing control, it is difficult to adequately respond to recent harmful exhaust gas regulations and requests for improved fuel efficiency in terms of accuracy, aging, etc., and electronic control is essential. It is becoming a common thing.

By the way, a general electronically controlled ignition timing control device uses the output of a reference position detector installed in the power distribution device as one input, and also uses a sensor that detects the operating status of the internal combustion engine such as intake manifold negative pressure. The optimum ignition timing is electrically calculated using the output of the ignition coil as another input, and the primary current of the ignition coil is turned on and off to control the ignition timing.

However, in this case, the high voltage generated on the secondary side of the ignition coil is distributed to each cylinder by the high-voltage power distribution mechanism of the power distributor as before, so even though an advance mechanism is not required, it is not necessary for the purpose of high-voltage power distribution. A power distributor is still required.

As a method for eliminating the above-mentioned problems, an ignition timing control device using a low-voltage power distribution method that does not perform high-voltage power distribution using a power distributor has been proposed.

However, the conventional low-voltage power distribution type ignition timing control device requires a separate device for identifying cylinders for power distribution, and has the drawback that the entire device becomes complicated.

This invention was made in view of the above-mentioned drawbacks of the conventional technology, and it is possible to perform cylinder identification based on the ignition timing reference signal, and to easily implement a highly accurate and stable ignition timing control system using a low-voltage power distribution system. It is intended to be obtained through composition.

In order to achieve this purpose, this invention
A first angle detector whose output state changes at a position advanced by a predetermined angle from the maximum ignition angle position of each cylinder of a four-cylinder internal combustion engine, and an output state which changes at the ignition angle position at the time of starting each cylinder. at least one sensor that detects the operating state of the internal combustion engine; an ignition timing control circuit that receives the outputs of the first and second angle detectors and the output of the sensor; A plurality of ignition coils connected to the ignition timing control circuit are provided, and the cylinder to which power is to be distributed is identified based on the output state of the first angle detector, and the ignition timing is set based on the change in the output state. It is something.

Hereinafter, this invention will be explained in detail based on FIG. 1, which is an embodiment.

In the figure, 1 is a rotating body attached to the crankshaft 4 of a 4-cylinder 4-cycle engine (not shown), and has a slit 110 formed at a 180 degree angle in a part of its disc. . 2 is a first angle detector whose output state changes from the first state to the second state or from the second state to the first state when facing the leading edge 110L or the trailing edge 110T of the slit 110; The first angle detector 2 is configured to invert the output at an angle advanced by a predetermined angle from the maximum ignition advance angle of each cylinder. 3 is installed with a predetermined phase difference angle from the first angle detector 2;
Similarly, there is a second angle detector whose output state is changed by the slit 110, and this second angle detector 3 is configured to reverse the output state at the starting ignition angle of each cylinder. . 5 is a negative pressure sensor that measures the intake manifold pressure of the engine and detects the operating state of the internal combustion engine; 6 is an ignition timing control circuit;
It is configured to input signals obtained from the first angle detector 2, second angle detector 3, and negative pressure sensor 5, and supply/cut off current to the ignition coils 7, 8 at appropriate timing. has been done.

The ignition coils 7, 8 have primary windings 70, 80 and secondary windings 71, 81, respectively, and one end 700, 800 of each of the primary windings 70, 80.
is connected to the positive side of the power supply 10 whose negative side is grounded, and the other ends 701 and 801 are connected to the ignition timing control circuit 6.
It is connected to the. In addition, output terminals 710, 711, 810, 81 of the secondary windings of the ignition coils 7, 8
1 are spark plugs 90, 91, 92, 93 respectively
is grounded through.

Next, the operation of the embodiment shown in FIG.
This will be explained with reference to the figures. In FIG. 2, a indicates the output of the first angle detector 2, and b
is the output of the second angle detector 3, c is the spark plug 9
0,91 ignition position, d is spark plug 92,93
This shows the ignition position.

First, the ignition order is spark plugs 90, 92, 9
Assume that the order is 1,93. When the rotating body 1 rotates in the direction of the arrow as shown in FIG. 1, the waveforms of the electric signals obtained from the first and second angle detectors 2 and 3 are as shown in FIGS. 2a and 2b. Become.

Now, the second angle detector 3 is inserted into the slit 11 provided in the rotating body 1 at the ignition position at the time of starting the engine.
If it is placed so as to face the leading edge 110L or trailing edge 110T of 0, the points P ₉₀ in FIG. 2 c and d,
P ₉₁ , P ₉₂ , P ₉₃ are spark plugs 90, 91, respectively.
This corresponds to the starting ignition position of the cylinders corresponding to 92 and 93. Therefore, for example, the point shown in Figure 2c
If the primary current of the ignition coil 7 is cut off at _P90 , high voltage is generated in the secondary winding 71, and the spark plug 90 can ignite the corresponding cylinder. In this case, a high voltage is also generated in the spark plug 91, but at this point, the cylinder corresponding to the spark plug 91 is in the exhaust stroke, so the pressure inside the cylinder is low and the spark plug 91 is discharged at a low voltage. Therefore, most of the voltage generated in the secondary winding 71 of the ignition coil 7 is applied to the ignition plug 90, and the energy necessary for ignition is supplied to the ignition plug 90.

Also, in FIG. 2c, the opposite occurs at point P ₉₁ . That is, point _P91 corresponds to the compression stroke of the cylinder corresponding to the spark plug 91, and the point P91 corresponds to the compression stroke of the cylinder corresponding to the spark plug 91.
Most of the high voltage generated in the secondary winding 71 of the spark plug 91 is applied to the spark plug 91. The same operation occurs at points P ₉₂ and P ₉₃ in FIG. 2d.

Therefore, when the output of the first angle detector 2 shown in FIG. 2a is at a "high level", the ignition coil is turned on when the output signal of the second angle detector 3 shown in FIG. 2b is reversed. 7, and when the output of the first angle detector 2 is at a "low level", the second
By cutting off the primary current of the ignition coil 8 when the output signal of the angle detector 3 is reversed, high voltage can be applied to the four spark plugs 90, 91, 92, and 93 in an appropriate order. . In an actual engine, the ignition timing is not fixed to the ignition timing at the time of starting as described above, but it is necessary to ignite at an appropriate timing depending on the operating conditions such as the engine speed and load condition. In the embodiment shown in FIG. 1, an ignition timing control circuit 6 is also used for this purpose. That is, the ignition timing control circuit 6 includes a sensor for detecting an ignition timing signal obtained from the first angle detector 2, an engine rotational speed signal obtained by measuring the cycle of this ignition timing signal, and the operating status of the engine. (Negative pressure sensor 5 in the embodiment shown in Figure 1)
An appropriate ignition position is calculated by inputting signals from the ignition coils 7 and 8, and the currents of the ignition coils 7 and 8 are controlled.

That is, as shown in FIG.
The edge of the signal waveform obtained from the angle detector 3 P ₉₀ ,
c advanced by the angle θ _A from P ₉₂ , P ₉₁ , P ₉₃ ,
An ignition signal is generated at (ignition timing) Q ₉₀ , Q ₉₂ , Q ₉₁ , Q ₉₃ shown in d, and when the output of the first angle detector 2 shown in a is "high level", the primary of the ignition coil 7 The current is cut off, and when the current is at a "low level", the primary current of the ignition coil 8 is cut off. In FIG. 3, the angle θ _A is an angle calculated and controlled by the ignition timing control circuit 6, and is generally called an advance angle.

Generally, it is necessary to control the ignition timing to a position that is advanced (earlier in time) than the _ignition position at the time of starting. It is impossible to control with reference to the point P ₉₁ shown in c, and the point Q ₉₁ shown in c
Control is performed as a delayed signal (or angle) from point P ₉₀ or point P ₉₂ shown in more advanced b. In this case, there is a maximum phase difference of 180 degrees from point P ₉₂ shown in b to Q ₉₁ shown in c, and it is extremely difficult to control point Q ₉₁ with high precision. This is especially noticeable if the engine is not running smoothly, and if there are sudden fluctuations in engine speed, the ignition may be fired at an abnormal angle, causing the engine to stall or, in more extreme cases, It is also possible to destroy the engine.

This invention also solves these problems. That is, in the embodiment shown in FIG. 1, the reversal position of the output of the second angle detector 3 is determined to correspond to the ignition timing at the time of starting, as described above, but the inversion position of the output of the first angle detector 2 is The reversal position is determined to correspond to a position that is a certain amount ahead of the maximum advance angle required by the engine.
Therefore, θ _M in FIG. 3 has a value that is a certain angle larger than the maximum advance angle amount. Therefore, in the ignition timing control circuit 6, each ignition timing Q ₉₀ , Q ₉₂ , Q ₉₁ , Q ₉₃ shown in FIG.
The edge of the signal waveform obtained from the angle detector 2 R ₉₀ ,
Since it can be controlled as a delay from R ₉₂ , R ₉₁ , and R ₉₃ , control accuracy is greatly improved, and furthermore,
Each point shown in c and d (ignition timing) Q ₉₀ , Q ₉₂ , Q ₉₁ ,
By adding restrictions so that Q ₉₃ does not advance beyond the edges R ₉₀ , R ₉₂ , R ₉₁ , and R ₉₃ shown in a, respectively,
Even when abnormal rotational fluctuations occur, abnormal advance angle can be prevented, which has a great effect on engine stability.

Furthermore, since the first and second angle detectors 2 and 3 detect the same single slit 110 disposed on the rotating body 1, periodic information from the output signal of each angle detector is obtained. This makes it possible to accurately determine engine rotational cycle fluctuations, which enables highly accurate predictive control of ignition timing even in transient conditions when the engine speed increases or decreases.

Furthermore, although it is obvious that the variation in the ignition timing of each cylinder depends on the precision of the slit, in the above embodiment, since only one common slit is required, there is an advantage that the precision can be easily improved. have.

In the above explanation, a negative pressure sensor was used as an example of a sensor for detecting the operating status of the engine, but the present invention is not limited to this, and other sensors such as cooling water temperature, atmospheric pressure, Even if a signal from a sensor such as air temperature is inputted to the ignition timing control circuit 6 to control the ignition timing, this does not affect the essence of the present invention.

As explained above, according to the present invention, in a four-cylinder internal combustion engine, the output signal of the first angle detector changes the output state at a position advanced by a predetermined angle from the maximum ignition advance position of each cylinder. By using the output signal of the second angle detector whose output state changes depending on the ignition angle position at the time of starting each cylinder, it is possible to identify the cylinder to which power is to be distributed and to set the ignition timing accurately and stably. , a low-voltage power distribution type ignition timing control device can be obtained with a simple configuration. In addition, it is possible to perform ignition at an appropriate time depending on the operating status of the engine, and it is also possible to reduce variations in ignition timing between cylinders.
The practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an ignition timing control device according to the present invention, and FIGS. 2 and 3 are waveform diagrams for explaining the operation of the embodiment shown in FIG. In the figure, 2 is a first angle detector, 3 is a second angle detector, 5 is a negative pressure sensor, 6 is an ignition timing control device, 7, 8 are ignition coils, 90, 91, 92, 9
3 is a spark plug.

Claims (1)

[Claims] 1 A first angle detector whose output state changes at a position advanced by a predetermined angle from the maximum ignition angle position of each cylinder according to the rotation of the four-cylinder internal combustion engine; a second angle detector whose output state changes depending on the ignition angle position at the time of starting the engine; at least one sensor that detects the operating state of the internal combustion engine; and the outputs of the first and second angle detectors; The output of the first angle detector includes an ignition timing control circuit that receives the output of the sensor as input and controls the ignition timing of each cylinder, and a plurality of ignition coils that are controlled by the ignition timing control circuit. An ignition timing control device for a four-cylinder internal combustion engine, characterized in that the cylinder to which power is to be distributed is identified based on the state, and the ignition timing is set based on a change in the output state.