JPH04262068A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the load of a microcomputer by providing multiple rotation signal generators, setting the preset periods to the timer of the microcomputer in response to the first and second reference positions, and performing excitation and ignition after the preset periods. CONSTITUTION:Multiple rotation signal generators 1, 10 are provided at different crank positions, the rotation angle signal is generated at every preset rotation angle in response to the rotation angle of the crank shaft of an internal combustion engine, and the rotation angle signal is omitted at the preset crank angle one or more times. The omission angle position of the rotation angle signal is detected by multiple reference position detecting circuits 3, 12. Preset periods are set respectively from the omission angle position by a microcomputer 4, and excitation and ignition are performed after these preset periods.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine, and more particularly to an ignition timing control device for an internal combustion engine that can reduce the burden on a microcomputer as a control means.

0002

2. Description of the Related Art FIG. 5 is a block diagram showing a conventional ignition timing control device for an internal combustion engine. In the figure, 1 is a rotation signal generator that generates a rotation angle signal as described later, 2 is an interface circuit that takes in the rotation angle signal from the rotation signal generator 1 and performs waveform shaping, etc., and 3 is a rotation signal whose waveform has been shaped. The pulse position where the angle signal is missing is detected and the reference position (re
4 is a microcomputer that receives the outputs of the interface circuit 2 and the reference position detection circuit 3 and determines the ignition timing and the energization timing.

[0003] In order to control ignition timing, fuel injection, etc. of an internal combustion engine, a signal synchronized with the rotation of the engine is used. A rotation signal generator 1 is used to obtain this signal. As the rotation signal generator 1, a crankshaft sensor is used, which is attached to the crankshaft 5 of the engine and detects the rotation of the crankshaft 5, as shown in FIG. As shown in FIG. 8, the crankshaft 5 has a gear 6 on its outer periphery, and a toothless portion 7 is provided at a predetermined portion of the gear 6. When the rotational signal generator 1 is placed close to such a gear 6, the interface circuit 2 which has waveform shaped the output of the rotational signal generator 1 generates a signal corresponding to the toothless portion 7 as shown in FIG. A rotation angle signal with discontinuities is obtained. In this way, the rotation angle signal has a discontinuous portion at a portion corresponding to a predetermined reference position so that the engine reference position can be detected, and this makes it possible to detect the engine reference position and engine angle. ing. That is, the rotation angle signal in FIG. 9 has a high level for each unit angle (for example, every 1° C.A.).
It changes alternately with a low level, and pulses corresponding to predetermined reference positions of each cylinder are omitted.

Next, the operation of the conventional ignition timing control device for an internal combustion engine shown in FIG. 5 will be described with reference to FIG. 6. Now, when a rotation angle signal as shown in FIG. 6(a) is supplied from the rotation signal generator 1 to the reference position detection circuit 3 through the interface circuit 2, as shown in FIG. A counter (not shown) counts this, and when the period level exceeds the reference detection threshold level, a reference position detection signal is generated as shown in FIG. 6(c), and this reference position detection signal is sent to the microcomputer. 4, and the microcomputer 4 is shown in FIG. 6(d).
As shown in the figure, the rotation angle signal is counted by a predetermined number from this reference position detection signal to determine the energization timing or the ignition timing.

[0005]

[Problems to be Solved by the Invention] A conventional ignition timing control device for an internal combustion engine is constructed as described above, and a microcomputer performs energization and ignition by counting rotation angle signals (number of teeth) from a reference position one by one. Therefore, there was a problem in that the burden on the microcomputer increased. This invention was made to solve the above-mentioned problems, and an object thereof is to provide an ignition timing control device for an internal combustion engine that can reduce the burden on a microcomputer.

[0006]

[Means for Solving the Problems] An ignition timing control device for an internal combustion engine according to the present invention is installed at different crank positions of the internal combustion engine, and outputs a rotation angle signal at every predetermined rotation angle corresponding to the rotation angle of the crankshaft. a plurality of rotation signal generators that cause the rotation angle signal to be missing at least once at a predetermined crank angle; and a plurality of reference position detection circuits that detect the angular position where the rotation angle signal from the plurality of rotation signal generators is missing. and a control means that sets a predetermined time from each of the missing angle positions and conducts energization and ignition after the predetermined time.

[0007]

[Operation] In this invention, by setting a predetermined time from the missing angle position to energization and ignition in the timer of the control means, and carrying out energization and ignition after the elapse of this predetermined time, the burden on the microcomputer as the control means is reduced. Make it smaller.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention,
1 to 7 are the same as described above. In this embodiment, a rotation signal generator 10 which operates in the same manner as the rotation signal generator 1 is provided in addition to the rotation signal generator 1. The rotation signal generator 10 is provided at a predetermined distance from the rotation signal generator 1, as shown in FIG. Furthermore, an interface circuit 11 and a reference position detection circuit 12 are provided in series on the output side of the rotation signal generator 10. The output of the reference position detection circuit 12 is supplied to the microcomputer 4. Here, the rotation signal generator 1 generates a rotation angle signal having a missing angular position related to the ignition timing, that is, a first reference position ref1, and the rotation signal generator 10 generates a rotation angle signal having a missing angular position related to the energization timing, that is, a second reference position ref1. reference position re
A rotation angle signal having f2 is generated. Therefore, the reference position detection circuit 3 detects the first reference position re.
The reference position detection circuit 10 detects the second reference position ref2.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be explained with reference to FIGS. 3 and 4. Here, the first reference position is set to a position where ignition noise is not superimposed, that is, on the advance side of the required maximum advance angle position. For example, Figure 3 (
As shown in a), the first reference position ref1 is set to BTDC (
before top dead center) set at 75°. Further, as shown in FIG. 3(b), the second reference position ref2 is set at 5° BTDC. Then, from the rotation signal generator 1 to the interface circuit 2
When a rotation angle signal as shown in FIG. 4(a) is supplied to the reference position detection circuit 3 through the reference position detection circuit 3, a counter (not shown) provided therein counts this as shown in FIG. 4(b). When the periodic level exceeds the reference detection threshold level, a reference position detection signal is generated as shown in FIG. 4(c), and this reference position detection signal is supplied to the microcomputer 4.
As shown in FIG. 4(d), a predetermined time Ta is set in an internal timer (not shown), and ignition is performed after this predetermined time Ta. Here, if the target ignition timing that can be set in advance is θA, and the cycle of the reference position is T, the predetermined time Ta can be determined from the following equation. Ta=(75°-θA)×T/180° Also, when the rotation angle signal is supplied from the rotation signal generator 10 to the reference position detection circuit 12 through the interface circuit 11, a counter (not shown) provided inside the rotation angle signal is supplied to the reference position detection circuit 12. ) counts this, and when its cycle level exceeds the reference detection threshold level, it generates a reference position detection signal, and this reference position detection signal is supplied to the microcomputer 4. At this point, the microcomputer 4 A predetermined time Tb is set in a timer (not shown) as shown in FIG. 4(d), and energization is performed after this predetermined time Tb. Here, the target ignition timing that can be set in advance is θA, the period of the reference position is T, and the energization time is T.
c, the predetermined time Tb can be calculated from the following equation. Tb={(180°-θA-5°)×T/
180°}-Tc Of course, energization is performed prior to ignition, and the predetermined time Tb in FIG. 4(d) is set by the previous detection of the second reference position ref2. Note that the reason why the output (rotation angle signal) of the interface circuit 2 is directly supplied to the microcomputer 4 is to use it for cylinder pressure control and misfire detection.

0010

As described above, according to the present invention, the rotation angle signal is installed at different crank positions of an internal combustion engine, and generates a rotation angle signal at each predetermined rotation angle corresponding to the rotation angle of the crankshaft. a plurality of rotation signal generators that cause the rotation angle signal to be missing one or more times; a plurality of reference position detection circuits that detect the missing angular position of the rotation angle signal from the plurality of rotation signal generators; Each of the motors is equipped with a control means for setting a predetermined time and for energizing and igniting after the predetermined time, and the microcomputer as the control means need only set the predetermined time on a timer without counting the rotation angle signal. This has the effect of providing an ignition timing control device for an internal combustion engine that can reduce the burden on the microcomputer.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a layout diagram of essential parts of the invention.

FIG. 3 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 4 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 5 is a configuration diagram showing a conventional ignition timing control device for an internal combustion engine.

FIG. 6 is a waveform diagram for explaining the operation of FIG. 5;

FIG. 7 is a layout diagram of a rotation signal generator.

FIG. 8 is a layout diagram of a rotation signal generator.

FIG. 9 is a waveform diagram for explaining the operation of the rotation signal generator.

[Explanation of symbols]

1, 10 Rotation signal generator 2, 11 Interface circuit 3, 12 Reference position detection circuit 4 Microcomputer

Claims (1)

[Claims] Claim 1: A rotation angle signal installed at different crank positions of an internal combustion engine, generating a rotation angle signal at every predetermined rotation angle corresponding to the rotation angle of the crankshaft, and causing the rotation angle signal to be omitted one or more times at a predetermined crank angle. a plurality of rotation signal generators; a plurality of reference position detection circuits that detect missing angular positions of rotation angle signals from the plurality of rotation signal generators;
An ignition timing control device for an internal combustion engine, comprising: a control means that sets a predetermined time from each of the missing angle positions, and performs energization and ignition after the predetermined time.