JP2731926B2 - Ignition timing control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for a vehicle engine at the time of acceleration, and more particularly, to a measure for reducing a snatch due to a change in engine speed at the time of acceleration.

[Conventional technology]

In recent years, the ignition timing of the vehicle engine is set in advance by a map, and the electronic control is always optimally controlled by searching this map under each operating condition. here,
When the engine is operated steadily, smooth changes in the amount of intake air, fuel, ignition timing, etc., are ensured. On the other hand, during rapid acceleration, the amount of intake air, fuel, ignition timing, and the like change drastically greatly. In the transient state of acceleration start, torsional vibration of the drive system is caused, and the engine speed rises while fluctuating greatly, causing shock and shock. A snatching phenomenon of vibration occurs, leading to deterioration of riding comfort. For this reason,
It is desired to reduce such a transient snatch, and as a countermeasure against this, it has been proposed to suppress fluctuations in the engine speed by ignition timing control.

Therefore, conventionally, there is a prior art in Japanese Patent Application Laid-Open No. Sho 59-201971 regarding ignition timing control as a measure for reducing the snatch. Here, it is shown that when the change amount of the engine speed is positive, the ignition timing is retarded in proportion to the positive amount, and the ignition timing is advanced in proportion to the negative amount when the change amount is negative.

[Problem to be solved by the invention]

By the way, in the above-mentioned prior art, in order to prevent excessive snatching, it is necessary to significantly advance and retard the ignition timing, and there is a problem that knocking occurs and the combustion of the engine is greatly deteriorated. is there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to control ignition timing capable of effectively reducing a snatch while maintaining good acceleration with an increase in engine speed during acceleration. It is to provide a device.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, in an ignition timing control device for setting an ignition timing according to an operating state of an engine, a threshold is set within a fluctuation range of an engine speed during acceleration. When the engine speed exceeds the threshold, the ignition timing is retard-corrected.

In the invention described in claim 2, the threshold is set by passing the engine speed through a low-pass filter.

According to a third aspect of the present invention, the time constant of the low-pass filter is variably set in accordance with the shift speed.

[Action]

Based on the above configuration, when the engine speed fluctuates and rises during acceleration, the ignition timing is retarded only within a range larger than the threshold value for the fluctuation of the engine speed, and the output torque is reduced. Fluctuations are reduced.

Therefore, there is a feeling of acceleration together with the reduction of the rotation fluctuation, and the snatch is also reduced.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 2, an outline of an engine to which the present invention is applied will be described. Reference numeral 1 denotes an engine body, 2 denotes a combustion chamber, and an ignition plug 3 is installed in the combustion chamber 2. In the intake system, an air cleaner 4 communicates with a throttle body 7 having a throttle valve 6 via an intake pipe 5, and the throttle body 7 communicates with a suction port 10 of the combustion chamber 2 having an intake valve 9 via an intake manifold 8. The injector 11 for injecting fuel into the suction port 10 is attached in a multipoint manner. On the other hand, the air cleaner 4
It has an air flow meter 12, which is provided immediately downstream of the vehicle and detects an intake air amount, a crank angle sensor 13, a shift position sensor 14, a clutch meet sensor 15 for detecting vehicle running due to clutch engagement, a water temperature sensor 16, and the like. Is input to the control unit 20. Then, a fuel injection signal from the control unit 20 is input to the injector 11 to perform fuel injection control,
An ignition signal is input to the ignition plug 3 via the ignition coil 17 and the distributor 18 to ignite at a predetermined timing.

In FIG. 1, the ignition timing control system of the control unit 20 will be described. First, it has an engine speed detecting unit 21 to which the speed signal of the crank angle sensor 13 is input, and detects the engine speed N. The engine speed N and the intake air amount Q of the air flow meter 12 are input to the basic fuel injection amount calculation unit 22, and the basic fuel injection amount Tp is calculated by Tp = K · Q / N (K is a constant). Yes, these engine speeds
N and the basic fuel injection amount Tp are input to the ignition timing setting unit 23. Here, the optimum ignition timing θIG according to each operating condition is previously determined in a map of the basic fuel injection amount Tp and the engine speed N, and the map is searched to set the optimum ignition timing θIG. The optimum ignition timing θIG is corrected under predetermined conditions by the correction unit 24 and input to the drive unit 25, and the crank angle sensor
An ignition signal is output at a predetermined timing before the piston top dead center based on the thirteen angle signals.

A correction control system for snatch reduction measures in the above control system will be described. First, it has an acceleration determination unit 26 to which the basic fuel injection amount Tp is input, and determines acceleration based on dTp / dt. Also,
It has a threshold value calculation unit 27 to which the signals of the engine speed N and the shift position S are input, and calculates a threshold value NB for the engine speed N. That is, a time constant corresponding to the signal of the current shift position S is selected as a low-pass filter from the time constants corresponding to each shift position, and the time constant is selected according to the fluctuation cycle of the engine speed N at the start of acceleration. Is changed as needed to apply a low-pass filter to the engine speed N, and the threshold value NB is set to the average of the fluctuation width along the rise of the engine speed N. The engine speed N and the threshold value NB are input to the comparison determination unit 28, and a control signal is output only when N> NB. The acceleration signal of the acceleration determination unit 26 is input to the control time setting unit 29 to set the control time t.
And the travel signal of the clutch meet sensor 15 are input to the retard amount setting unit 30.

On the other hand, the output of the comparison determination unit 28 is input to the retard amount setting unit 30. The retard amount setting unit 30 outputs a constant retard amount θ only when N> NB at the control time t in the clutch meet state.
L is output.

The retard amount θL is input to the correction unit 32, and the correction amount θN for the engine speed N, the correction amount θT for the water temperature T,
The correction is made by the correction amount θS for the shift position S. Here, the correction amount θ with respect to the engine speed N as shown in FIG.
N is a decreasing function with respect to the engine speed N, and the correction amount θT with respect to the water temperature T is an increasing function with respect to the water temperature T.
Is determined by an increasing function with respect to the gear ratio at the shift position S. Then, the retard correction amount θk is calculated by the following equation: θk = θL + θN + θT + θS. As a result, the retard amount θL
On the other hand, when the engine speed N is high, the water temperature T is low, and the gear ratio at the shift position S is small, the retard correction θk is corrected to decrease. The retard correction amount θk is input to the correction unit 24, and is configured to be retarded by θIG−θk.

Next, the operation of the ignition timing control device having such a configuration will be described.

First, during operation of the engine, air is sucked into the combustion chamber 2 of the engine body 1 in accordance with the opening of the throttle valve 6, and fuel is injected from the injector 11 to generate an air-fuel mixture. Then, at a predetermined time before the piston top dead center, the ignition plug 3 ignites and burns the air-fuel mixture through the ignition coil 17 and the distributor 18 by an ignition signal from the control unit 20, thereby generating an engine output.

Therefore, when the vehicle is stationary or when the vehicle is running, the ignition timing setting unit 23 of the control unit 20 sets the optimum ignition timing θIG according to each operating condition by the basic fuel injection amount Tp and the engine speed N. Then, an ignition signal based on the optimum ignition timing θIG is output to electronically control the ignition timing, so that the engine output is effectively generated and the output is increased.

On the other hand, when the vehicle accelerates while traveling, fuel is supplied together with a large amount of air, and the optimum ignition timing θIG is also set appropriately in this case. Therefore, the engine speed N and the engine output sharply increase. At the start of acceleration, especially the engine speed N rises while fluctuating as shown in FIG. 4 (a). Then, the acceleration is determined by the acceleration determination unit 26, the control time t is set, and the threshold value calculation unit
FIG. 4 (a) is at about the middle of the fluctuation range of the engine speed N at 27.
The threshold value NB is set as follows. Then, the comparison control unit 28 compares the engine speed N with the threshold value NB, and the retard amount setting unit 30 outputs a constant retard amount θL only when N> NB. The retard amount θL is corrected by the correction unit 32. However, under the conditions of a high water temperature T, a low engine speed N, and a low-speed gear, θL ≒ θk
The correction unit 24 determines the ignition timing θ as shown in FIG.
IG is retarded by the substantially retard amount θL.

For this reason, as shown in FIG. 4 (c), the increase in the engine torque is temporarily suppressed together with the engine speed, so that when the engine speed N decreases and N <NB, the ignition timing control of the optimum ignition timing θIG is performed. And the engine speed N is increased. Thus, during acceleration, the engine speed N
In accordance with the fluctuation state, the retard correction is performed only in the increase range of the engine speed N where N> NB, whereby the sudden increase in the engine speed N is suppressed and the engine speed N rises smoothly, thereby reducing the snatch. You.

Then, when the value converges to N = NB or when the control time t elapses, the output of θL is stopped, thereby returning to the original optimal ignition timing θIG again and increasing the output.

When the water temperature T is low, the retard amount θL is corrected to be reduced by the correction amount θT for the water temperature T, and good combustion is ensured. In addition, even when the engine speed N is high at a high gear, the retard amount θL is corrected to be reduced by the correction amounts θS and θN for the shift position S and the engine speed N, so that unnecessary retard is avoided.

As mentioned above, although one Example of this invention was described, it is not limited only to this.

〔The invention's effect〕

As described above, according to the present invention, in the snatch reduction by the ignition timing control at the time of acceleration, a threshold value is determined, and the retardation is corrected in a rectangular shape only when the engine speed is higher than the threshold value. Therefore, since the effective retard angle is limited to a minimum in a region equal to or higher than the average engine speed, the snatch can be reduced by reducing the fluctuation of the engine speed while minimizing the power loss.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of an ignition timing control device according to the present invention, FIG. 2 is a diagram schematically showing an engine to which the present invention is applied, FIG. The figure shows the ignition timing control state during acceleration. DESCRIPTION OF SYMBOLS 1 ... Engine main body, 3 ... Spark plug, 20 ... Control unit, 23 ... Ignition timing setting part, 24 ... Correction part, 26 ... Acceleration determination part, 27 ... Threshold value calculation part, 28 ... Comparison determination part, 30 ... Retard Quantity setting section

Claims (3)

(57) [Claims] An ignition timing control device for setting an ignition timing according to an operating state of an engine, wherein a threshold is set within a fluctuation range of the engine speed during acceleration, and the engine speed exceeds the threshold. An ignition timing control device, wherein the ignition timing is retard-corrected. 2. The ignition timing control device according to claim 1, wherein the threshold is set by passing the engine speed through a low-pass filter. 3. The ignition timing control device according to claim 2, wherein a time constant of said low-pass filter is variably set according to a shift speed.