JP2641270B2 - Ignition timing control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling an ignition timing of an internal combustion engine based on a reference position detection signal corresponding to each cylinder. The present invention relates to an ignition timing control device that prevents misfire due to advance angle.

[Prior Art] A conventional electronic ignition timing control device responds to a crank angle based on a reference position detection signal that is inverted at predetermined first and second reference positions, for example, as shown in FIG. The ignition timing is calculated, the ignition time and the energization start time are determined based on the time from the first and second reference positions, and the ignition timing and the energization time are controlled.

In this case, the first reference position is BTDC75 ゜ (75
The second reference position is BTDC5 ° (crank angle 5 ° before top dead center). The specific cylinder is identified using a cylinder identification signal (not shown) having a different phase from the pulse signal shown in FIG.

In such an ignition timing control device, since the ignition time is controlled by the timer time, as shown in FIG. 6, the target ignition timing is advanced from the second reference position (for example, about BTDC 8 °). When the falling edge of the pulse is abruptly advanced at the beginning of the rapid acceleration of the engine, the target ignition timing cannot follow the target, and the ignition timing is abnormally retarded from the second reference position. The abnormal ignition retard causes abnormal vibration called power loss and knocking.
In order to prevent this, conventionally, a so-called ignition timing stopping process for forcibly interrupting the ignition coil current at the time of detecting the second reference position has been performed.

On the other hand, for the purpose of identifying the cylinder only by the reference position detection signal, as shown in FIG. 7, the second reference position of only the specific cylinder is offset toward the advance side by a predetermined crank angle (for example, about 10 °). When the reference position detection signal is used, the second reference position is BTDC 15 ° only in the specific cylinder. In this case, the cylinder identification signal is unnecessary, and the specific cylinder is identified based on the difference in the cycle ratio of each pulse of the reference position detection signal.

However, if the above-described ignition timing stop processing is performed at the second reference position in FIG. 7, a time lag corresponding to a predetermined offset angle occurs for a specific cylinder, so that the ignition timing stop processing timing is abnormal. The angle is advanced, and a sufficient energizing time cannot be obtained, causing a misfire.

[Problems to be Solved by the Invention] In the conventional ignition timing control device as described above, a reference position detection signal in which the second reference position of the specific cylinder is offset to the advance side as shown in FIG. 7 is used. In this case, there is a problem that a time lag corresponding to a predetermined offset angle (abnormal advance angle) occurs at the time of stopping the ignition timing of the specific cylinder, which causes a misfire.

The present invention has been made in order to solve such a problem. When a reference position detection signal in which the second reference position of a specific cylinder is offset by a predetermined angle toward the advance side is used, the initial acceleration of the engine at the beginning of rapid acceleration is performed. It is an object of the present invention to obtain an ignition timing control device capable of preventing an abnormal advance of the ignition timing stopping process.

[Means for Solving the Problems] The ignition timing control device according to the present invention discriminates a specific cylinder by offsetting the second reference position of the reference position detection signal by a predetermined crank angle to the advance side only in the specific cylinder. Specific cylinder identification means to be performed, and a second cylinder other than the specific cylinder for each cylinder.
The ignition that immediately starts the ignition when the target ignition timing is set on the more advanced side than the crank angle of the engine corresponding to the reference position and the ignition has not yet been performed at the time when the second reference position is detected. It is provided with timing stop processing means and offset correction processing means for substantially delaying the ignition timing stop processing by a predetermined crank angle.

[Operation] In the present invention, before cylinder identification is determined, offset correction processing is performed for each cylinder and then ignition timing stop processing is performed, and after cylinder identification is determined, offset correction processing is performed for a specific cylinder. Then, the ignition timing is stopped.

FIG. 1 is a block diagram schematically showing an ignition timing control device according to an embodiment of the present invention.

In the figure, (1) is a rotation signal generator for generating a rotation signal corresponding to the reference position detection signal of FIG. 7, for example, the first and second rotations of each cylinder in synchronization with the crankshaft.
, A circular plate having an arc-shaped slit corresponding to the reference position (crank angle), and an optical sensor arranged to face the slit. (2) is an interface circuit connected to the rotation signal generator (1).

(3) a microcomputer for taking in a rotation signal via the interface circuit (2), a specific cylinder identification means (4) for identifying a specific cylinder by a cycle ratio of a reference position detection signal, and a second cylinder of the specific cylinder. Offset correction processing means (5) for substantially delaying the ignition timing stopping process by a predetermined crank angle offset advanced from the reference position, and a crank angle corresponding to the target ignition timing corresponding to the second reference position. When it is set to the more advanced side,
An ignition timing stopping process means (6) for performing an ignition timing stopping process when the second reference position is detected, and an ignition for calculating an ignition time and an energization start time by timer control based on a time from the first or second reference position. Time and energization start time calculating means (7).

FIG. 2 is a flowchart showing the operation sequence of the present invention.

FIG. 3 is an explanatory diagram showing a target ignition timing range to which the ignition timing stopping process is applied in association with a reference position detection signal waveform, wherein (a) shows a target ignition timing range after cylinder identification is determined;
(B) shows the target ignition timing range before the cylinder identification is determined, and A ₀
Is the target ignition timing range when the offset correction process is not performed,
A ₁ is the target ignition timing range in the case where the offset correction process.

4A and 4B are waveform diagrams showing a reference position detection signal and an ignition coil current according to the present invention, wherein FIG. 4A shows a reference position detection signal waveform, and FIG. 4B shows cylinder identification when the target ignition timing is fixed at BTDC20 °. It is a previous ignition coil current waveform.

Hereinafter, the operation of the ignition timing control device shown in FIG. 1 will be described with reference to FIG. 2 to FIG.

First, the specific cylinder identifying means (4) identifies a specific cylinder based on the cycle rate of each pulse of the reference position detection signal.
At this time, in a transient state such as the initial stage of the startup, the pulse cycle is not stationary, and there is a case where cylinder identification is difficult. Therefore, it is determined whether or not the cylinder identification is determined (Step S1). Then, it is determined whether the cylinder to be controlled is a specific cylinder (step S2).

If it is determined in step S2 that the specific cylinder is the specific cylinder, the offset correction processing means (5) performs the second correction of the specific cylinder.
In order to prevent abnormal ignition advance due to the offset advance of the reference position, the offset correction process is performed so that the pawl process is retarded by a predetermined crank angle (for example, 10 °) corresponding to the offset advance (step S3). That is, the third
As shown in FIG. 7A, the target ignition timing range to which the ignition timing stopping process is applied is reduced by a predetermined crank angle only for a specific cylinder, and the process proceeds to step S4.

If it is determined in step S2 that the cylinder is another cylinder, it is not necessary to perform the offset correction process on the other cylinder, and the process proceeds to step S4 bypassing step S3.

Accordingly, the ignition timing pawl processing means (6), the target ignition timing that is currently set, if it is in a range A ₀ for the other cylinders, also in the range A ₁ for specific cylinder In each case, the above-described ignition timing stop processing (step S
Do 4).

Here, the reason why the offset correction processing is performed by shortening the target ignition timing range to be stopped in step S3 is as follows.
This is because the ignition timing stopping process is performed based on the second reference position of the reference position detection signal, and thus the timing itself of the ignition timing stopping process itself cannot be directly delayed in step S4.

For example, the pawl applies target ignition timing range, is usually in the range A ₀ to a second reference position of the other cylinders from the first reference position (BTDC 75 °) (BTDC 5 °), at the time of the offset correction process, the 1 of the reference position in the range a ₁ to a second reference position of the specific cylinder (BTDC15 °). Therefore, if the target ignition timing is fixed at about BTDC 10 ° and the target ignition timing is retarded from the second reference position at the beginning of rapid acceleration, the second reference position (BTDC 5 ° ) Although the ignition timing pawl process is performed in, the target ignition timing for the specific cylinder because it exceeds the range a _1, not the ignition timing pawl processing performed, abnormal advance of the ignition timing is prevented.

On the other hand, if it is determined in step S1 that the cylinder identification has not been determined yet, the process proceeds to step S3 for offset correction processing bypassing step S2, and offset correction processing is performed for all cylinders. The stop processing (step S4) is performed. As a result, the abnormal ignition advance which causes a misfire is reliably prevented.

That is, the target ignition timing range ignition timing pawl is applied, as in the FIG. 3 (b), irrespective of the other cylinders or a specific cylinder is reduced to A ₁ for each cylinder. Therefore, when the target ignition timing is about 10 ° BTDC, the second
The second reference position (BTDC)
The ignition timing stop processing at 5 ° or BTDC 15 °) is not performed, and ignition is performed at the set target ignition timing.

At this time, for the other cylinders, the ignition timing is retarded, but there is no particular problem because the prevention of misfire has priority.

Also, a target ignition timing is about BTDC20 ° (range A ₁ within), when the target ignition timing on the rapid acceleration initial reaches the second reference position (BTDC15 °) from the retard side of the specific cylinder is the As shown in FIG. 4 (b), the ignition timing stopping process is performed at the second reference position of the specific cylinder. At this time, for other cylinders,
It goes without saying that the ignition timing stopping process is performed at the second reference position (BTDC5 °) as described above.

As described above, before the cylinder identification is determined, the offset correction process (Step S3) is performed on each cylinder, and then the ignition timing stopping process (Step S4) is performed. After the cylinder identification is determined, the specific cylinder is stopped. Only offset correction processing (step S
After performing 3), the ignition timing stopping process (step S4) is performed.

[Effects of the Invention] As described above, the present invention provides a specific cylinder identifying means for identifying a specific cylinder by offsetting the second reference position of the reference position detection signal only to a specific cylinder toward the advance side by a predetermined crank angle. For each cylinder, the target ignition timing is set to be more advanced than the crank angle of the engine corresponding to the second reference position other than the specific cylinder, and ignition is still performed at the time of detection of the second reference position. Ignition timing stop processing means for immediately igniting when not performed, and offset correction processing means for substantially delaying the ignition timing stop processing by a predetermined crank angle. After the offset correction process is performed on the ignition timing, the ignition timing is stopped, and after the cylinder identification is determined, the offset correction process is performed only on the specific cylinder, and then the ignition timing is stopped. As a result, regardless of whether the cylinder identification has been determined or not, there is an effect that an ignition timing control device that can prevent abnormal ignition advancement due to ignition timing stop processing at the time of transient of the engine such as at the beginning of rapid acceleration is obtained. .

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an ignition timing control device according to an embodiment of the present invention, FIG. 2 is a flowchart showing an operation sequence of the present invention, and FIG. 3 is target ignition to which ignition timing stopping processing is applied. FIG. 4 is an explanatory diagram showing a time range corresponding to a reference position detection signal waveform, FIG. 4 is a waveform diagram showing a reference position detection signal and an ignition coil current according to the present invention, and FIG. 5 is a waveform diagram showing a conventional reference position detection signal. FIG. 6 is a waveform diagram of a reference position detection signal and an ignition coil current of a conventional device having an ignition timing stopping function, and FIG. 7 is a reference when the second reference position is offset by a predetermined crank angle only in a specific cylinder. FIG. 6 is a waveform chart showing a position detection signal. (1) Rotation signal generator (4) Specific cylinder identifying means (5) Offset correction processing means (6) Ignition timing stop processing means (7) ... Ignition time and energization start time calculation means BTDC75 ゜: first reference position BTDC5 ゜, BTDC15 ゜: second reference position A ₀ ... target ignition timing range A ₁ to which ignition timing stop processing before offset correction processing is applied A1 ... after offset correction processing Target ignition timing range to which the ignition timing stopping process is applied S1 ... Step of determining cylinder identification confirmation S2 ... Step of determining a specific cylinder S3 ... Step of performing offset correction processing S4 ... Start of ignition timing stopping processing Steps In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] An ignition timing is calculated based on reference position detection signals indicating predetermined first and second reference positions corresponding to respective cylinders in synchronization with rotation of an engine, and the first or second reference value is calculated. An ignition timing control device for controlling an ignition timing according to a time from a position, wherein a specific cylinder is identified by offsetting the second reference position of the reference position detection signal by a predetermined crank angle toward an advance side only in a specific cylinder. A specific cylinder identification means, and a target ignition timing is set for each cylinder at a more advanced side than a crank angle of the engine corresponding to a second reference position other than the specific cylinder, and the second reference position Ignition timing stop processing means for immediately igniting when the ignition has not yet been performed at the time of detection, and offset compensation for substantially delaying the ignition timing stop processing by the predetermined crank angle. Before the identification of the cylinder, the offset correction process is performed for each cylinder, and then the ignition timing stopping process is performed. After the identification of the cylinder is determined, the offset is performed for the specific cylinder. An ignition timing control device, wherein the ignition timing stopping process is performed after performing a correction process.