JPH0650104B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

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 a device for correcting and controlling a basic advance value during acceleration.

(Prior Art) In recent years, there has been an increasing demand for reduction of exhaust gas and improvement of fuel efficiency, and even with respect to ignition timing, in order to maintain and improve running performance while satisfying these requirements, precision and complexity that were impossible with conventional devices An electronically controlled ignition timing control device for performing various ignition timing control has been put into practical use (see Nissan Motor Co., Ltd., RB engine maintenance manual, page 42).

To describe such a device, an intake air amount signal and an engine speed signal are input as a representative value representing the engine operating state to a control unit that not only controls the ignition timing but also intensively controls the fuel injection amount. The basic injection amount Tp necessary for combustion is calculated from the engine speed N and the intake air amount Qa obtained by signal processing of The basic advance angle value is calculated. This basic advance angle value is stored in advance in a memory constituting the control unit as a basic advance angle value map corresponding to N and Tp, for example, and is read out from a table lookup. The normal ignition advance value is determined by being corrected by the engine water temperature or the like indicating the operating state. In this case, the ignition advance value is stored as a numerical value representing the crank angle before top dead center, and the primary current of the ignition coil is cut off at the crank angle before top dead center corresponding to the ignition advance value. An ignition signal is sent to the power transistor for ignition. In this way, the ignition timing is optimally controlled based on the ignition advance value preset according to the operating state.

(Problems to be solved by the invention) By the way, in order to improve the output and the fuel consumption, the ignition timing is set to MB.
Although it is preferable to set to T, the basic advance value is set with a margin to a predetermined value that is retarded from the MBT in consideration of occurrence of knocking. In this case, the basic advance angle value is set for the steady operation which occupies most of the operation range, and therefore represents the required ignition advance value for the steady operation. On the other hand, at the time of sudden acceleration, the intake temperature is not higher than that at the time of steady operation, so there is a margin to generate knocking, and if it can be advanced by that amount and approached to MBT, the combustion pressure will be effective. It becomes possible to use it, and the torque generated during sudden acceleration is improved.

However, if the ignition timing is advanced all the way to MBT at the same time as the sudden acceleration, the torque rises sharply, so that in the initial stage of the sudden acceleration, the sudden fluctuation of the torque causes vibration and temporarily disturbs the drivability.

In view of this, the present invention provides an ignition timing control device that effectively uses a margin corresponding to a difference in intake air temperature during acceleration when the basic advance value is set based on MBT during steady state. The purpose is to do.

(Means for Solving Problems) The present invention, as shown in FIG. 1, is a rotational speed detecting means 1 for detecting the rotational speed of the engine, and a hot wire type air amount detecting means for detecting the intake air amount of the engine. 2, a basic advance value calculation means 3 for obtaining a basic advance value set based on the MBT in a steady state by referring to a map using these detected values as parameters, an acceleration determination means 4 for determining a sudden acceleration, and an acceleration Acceleration degree calculation means 5 for calculating the degree, correction amount calculation means 6 for calculating the advance value correction amount according to the acceleration degree and the retard value correction amount according to the acceleration degree, and from the time of the rapid acceleration determination First
The basic advance value is retarded by the retard value correction amount according to the acceleration degree until a predetermined period of time, and the advance according to the acceleration degree is performed from the lapse of the first predetermined period to the second predetermined period. A correction means 7 for advancing the basic advance value by the amount of correction of the angle value and an ignition coil 1 according to the corrected advance value.
Ignition means 8 for shutting off the next current, knocking determination means 31 for determining whether knocking has occurred during the advance angle correction, and when knocking occurs from the determination result, the advance angle is advanced with respect to the correction means 7. An advance angle correction stop instruction means 32 for instructing stop of correction is provided.

(Operation) During sudden engine acceleration, knocking is less likely to occur because the intake air temperature is not higher than during steady operation, and the first predetermined value is set by the advance value correction amount that is a correction amount corresponding to the margin. When the correction means 7 increases the basic advance value and advances the ignition timing during the rapid acceleration from the passage of time to the second predetermined time,
The ignition timing is set closer to MBT than during steady-state operation, and the combustion pressure can be effectively used accordingly, and the torque generated during rapid acceleration can be improved.

Also, if knocking occurs even during the advance angle correction described above,
Since it is determined that the intake air temperature is approaching the steady-state intake air temperature and the advance angle correction is stopped, a higher engine output than the steady state is generated over the time until the intake air temperature rises.

Further, in the initial stage of the rapid acceleration from the time when the rapid acceleration is determined to the first predetermined time, if the correction means 7 corrects the basic advance value by decreasing the ignition timing and retards the ignition timing, the combustion is delayed and the torque rises. To slow down the clenching vibration and obtain smooth acceleration.

Furthermore, the greater the degree of acceleration, the greater the difference in intake air temperature in each steady state immediately before and after the sudden acceleration. Therefore, the degree of acceleration increases from the time when the first predetermined time elapses to the second predetermined time. When the advance value correction is set accordingly, the amount of advance value correction is given in just proportion to the degree of acceleration,
An extremely high output can be obtained no matter what the sudden acceleration.

Similarly, the greater the degree of acceleration, the greater the amount of intake air (that is, the increase in engine output). Therefore, the retard correction amount is set according to the degree of acceleration until the first predetermined time after the rapid acceleration determination. Then, the retard correction amount is given in accordance with the degree of acceleration without excess or deficiency, thereby reducing the scratching vibration at the initial stage of rapid acceleration under various rapid acceleration conditions.

(Embodiment) FIG. 2 is a schematic view of a mechanical structure of an embodiment of the present invention. This example is an example in which the ignition timing control is performed by electronic control, and the control is centrally performed by a control unit 10 including a central processing unit, a memory, and an input / output signal processing circuit. That is, the input / output signal processing circuit of the control unit 10 includes a hot wire type air flow meter 1 for detecting the amount of air taken into the engine.
4, an intake air amount signal from the crankshaft, a signal for every 1 ° of crank angle of the crankshaft, a 1 ° signal from a crank angle sensor (built in the distributor 15) for detecting a predetermined position of the crank angle, a crank angle reference position signal, an intake throttle A throttle valve opening signal from the throttle valve opening sensor 16 that detects the opening of the valve 21, a temperature signal from the temperature sensor 17 that detects the cooling water temperature, and a knocking signal from the knock sensor 18 that detects knocking are input. It The knock sensor 18 is composed of a piezoelectric element and converts vibration generated in the cylinder block into an electric signal. 20
Is an engine body, 22 is a fuel injection valve, 23 is a spark plug, 2
4 is a turbocharger and 25 is a catalyst.

FIG. 3 is a flow chart showing the contents of operations performed in the central processing unit shown in FIG. The numbers indicate the steps. The operation of this embodiment will be described based on this flow chart. In 30 and 31, the engine speed N obtained by counting the 1 ° signal for a predetermined time and the intake air amount signal converted into a digital value by the A / D converter. In addition to reading the intake air amount Qa and throttle valve opening Θ obtained from the throttle valve opening signal,
The knocking level obtained by signal processing the knocking signal is read. In 32, the basic injection amount Tp (= K · Qa / N, where K is a constant) required for combustion is calculated from N and Qa to form the basis of the injection amount control.
The basic advance value MAPadv of the ignition timing is calculated using _p and N. Specifically, in this example, the basic advance value MAPadv corresponding to N and Tp is stored in advance in the memory forming the control unit 10, and is read from the advance value map ADVMAP by table lookup. MAPadv corresponds to a predetermined ignition timing retarded from MBT and is stored as a numerical value representing a crank angle before compression top dead center. Next, at 34, the gradient ΔΘ / ΔT of the throttle valve opening Θ per unit time is calculated. This ΔΘ / ΔT represents the degree of acceleration, and at 35, the acceleration initial retard correction amount ADVr and the acceleration margin advance angle correction amount ADVa are calculated according to the ΔΘ / ΔT. At 36, it is confirmed whether or not the throttle valve 21 is fully opened, and if not fully opened, it is determined that it is not during rapid acceleration, and 37
Then, MAPadv is set as the required advance value ADV at this time.
When the ADV obtained in this way is output to the input / output signal processing circuit at 38, the crank angle ADV ° before compression top dead center becomes OF.
It is converted into an ignition signal of F, and a power transistor (not shown) cuts off the primary current of the ignition coil by this ignition signal, and ignition is performed.

Next, at 36, if the throttle valve 21 is fully opened, it is determined that rapid acceleration is in progress, and the routine proceeds to 39. In 39, the time T from the time when the throttle valve 21 is fully opened is compared with the acceleration initial delay time (first predetermined time) T1, and if T is T <T1, the time to perform the retard correction in the initial acceleration. It is determined that it is inside the
ADVr is subtracted from APadv and the required advance value A at this time
DV (= MAPadv-ADVr) is calculated. Time has passed 3
When it is determined in 9 that T is T ≧ T1 and the acceleration initial retard timing is exceeded, the program proceeds to 41, in which T is compared with the acceleration time (second predetermined time) T2 (T2> T1). T is T <T2
If so, it is determined that the vehicle is accelerating and the MAPad is determined at 43.
ADVa is added to v and the required advance angle value ADV (=
Calculate MAPadv + ADVa). If it is determined at 41 that T is T ≧ T2 and acceleration is completed, MAPadv is not corrected, and at 37, MAPadv is AD as it is.
V. Even if T is T1 ≦ T <2, the throttle valve 2
If 1 is not fully open, MAPadv is not corrected.

In this example, feedback control is performed based on the signal from the knocking sensor 18. In such a device, it is confirmed whether or not knocking occurs at 42,
If it is determined that knocking has not occurred, the ignition timing is advanced to add ADVa to MAPadv as described above, and if knocking is detected, MAPadv is not corrected. In this case, the feedback control based on the signal from the knocking sensor 18 is subsequently performed.
That is, the retard angle correction is performed by decreasing the value from MAPadv by a predetermined value at regular intervals, and the target knocking level is converged. On the other hand, when it is at the low level, on the other hand, advance correction is performed to increase the MAPadv by a predetermined value at regular intervals until the target knocking level is reached, and the target knocking level is converged. Thus, during steady operation, the ignition timing is controlled to the target knocking level.

FIG. 4 is a characteristic diagram showing the action and effect at the time of sudden acceleration according to this embodiment in comparison with the conventional example in terms of engine speed and shaft torque. The solid line shows the conventional example, and the broken line shows this embodiment.

As shown in the figure, the elapsed time T from the sudden acceleration determination is T1.
≤T <T2 During acceleration, the basic advance value MAPad
By adding ADVa to v, the advance angle correction is performed by filling the acceleration margin corresponding to the intake air temperature increase, which is generated during the sudden acceleration. Therefore, during sudden acceleration, it is possible to advance to a position closer to MBT than during steady operation, and as a result, it is possible to increase the maximum combustion temperature, improve torque during acceleration, and improve acceleration performance.

Also, if knocking occurs even during the advance angle correction described above,
Since it is judged that the intake air temperature is approaching the steady-state intake air temperature and the advance angle correction is stopped, it is possible to generate a higher engine output than the steady state for the time until the intake air temperature rises. it can.

On the other hand, the ignition timing is set to M even in the initial stage of rapid acceleration where T is T <T1.
When the angle is advanced all the way to the vicinity of BT at once, the torque rises sharply due to a good combustion pressure, so that a jerk vibration occurs due to the sudden change in the torque at the initial stage of the rapid acceleration.

On the other hand, in this embodiment, MAPadv
The ignition timing is reduced to MBT by subtracting ADVr from
The delay angle is corrected with a margin. For this reason, the combustion becomes gentle, and the scribing vibration due to the sudden change of the torque can be alleviated.

Further, the larger the degree of acceleration, the larger the difference in intake air temperature between each steady state immediately before and after the sudden acceleration. Therefore, the advance value correction is set according to the degree of acceleration during the sudden acceleration ( For example, by increasing the amount of advance value correction as the degree of acceleration increases), when performing rapid acceleration with the throttle valve fully open, the rapid acceleration from any throttle valve position regardless of the throttle valve position before the rapid acceleration. It is possible to obtain an extremely high output even by performing.

Similarly, as the degree of acceleration increases, the amount of intake air increases (that is, the engine output increases). Therefore, the retard correction amount is set in accordance with the degree of acceleration at the initial stage of rapid acceleration (for example, acceleration). By increasing the retard value correction amount as the degree increases, it is possible to give the retard value correction amount without excess or deficiency according to the degree of acceleration. Can be reduced.

It should be noted that the width or time of the scribing vibration varies, and it is easy to set the ADVr and T1 correspondingly.

By the way, in this example in which the intake air amount is detected by a hot-wire type air flow meter, there is no response delay at the time of rapid acceleration due to the inertia of the flap unlike the flap type, so during hot acceleration, From the intake air amount Qa detected by the air flow meter and the rotation speed N, the basic advance value M
Even if APadv is determined and ignition is performed with this basic advance value MAPadv, the ignition timing will not be over-advanced or over-retarded, and therefore knocking due to over-advance will not occur. .

However, even if the rotation speed and the intake air amount are the same, the intake air temperature is lower during steady acceleration than during steady state, so if it is possible to advance the angle by a small amount while avoiding knocking, the output during steady state Can produce a higher output. This example does not correct the over-advanced angle or the over-retarded angle caused by the response delay at the time of sudden acceleration that occurs in a flap type air flow meter etc. Is to use effectively.

(Effects of the Invention) The present invention is directed to a rotational speed detection means for detecting the rotational speed of an engine, a hot-wire air amount detection means for detecting the intake air amount of the engine, and a detection value of these as a parameter which is determined by a map reference. A basic advance value calculating means for obtaining a basic advance value set based on the constant MBT, an acceleration determining means for determining a sudden acceleration time, an acceleration degree calculating means for calculating an acceleration degree,
Correction amount calculating means for calculating an advance value correction amount corresponding to the degree of acceleration and a retard value correction amount corresponding to the degree of acceleration,
The basic advance value is retarded by the retard value correction amount according to the degree of acceleration from the sudden acceleration determination to the first predetermined period, and the second predetermined period from the elapse of the first predetermined period. Correction means for advancing the basic advance value by an advance value correction amount according to the acceleration degree, and ignition means for cutting off the primary current of the ignition coil in accordance with the corrected advance value.
Knocking determination means for determining whether knocking has occurred during the advance angle correction, and advance angle correction stop instruction means for instructing the correction means to stop the advance angle correction when knocking occurs from this determination result. Since it is provided, during the rapid acceleration, it is sufficient to draw out the engine output by an amount corresponding to the difference in intake air temperature from the steady state during the period until the intake air temperature rises to the steady state intake air temperature. In addition to high acceleration, the sudden increase in engine output can be suppressed in the early stages of sudden acceleration to reduce the rattling vibration, and the advance angle correction amount and retard angle correction according to the degree of acceleration can be reduced. Since the amount and the quantity are given in just proportions, extremely high output can be obtained even in any sudden acceleration, and the scratching vibration at the initial stage of rapid acceleration can be reduced under various rapid acceleration conditions.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. FIG. 2 is a schematic view of a mechanical structure of an embodiment of the present invention,
FIG. 3 is a flow chart showing the contents of operations performed by the central processing unit in FIG. FIG. 4 is a characteristic diagram showing the action at the time of sudden acceleration according to this embodiment in comparison with the conventional example in terms of engine speed and shaft torque. 1 ... Rotation speed detecting means, 2 ... Hot wire type air amount detecting means,
3 ... Basic advance value calculating means, 4 ... Acceleration determining means, 5 ...
... acceleration degree calculation means, 6 ... correction amount calculation means, 7 ... correction means, 8 ... ignition means, 10 ... control unit, 14 ... air flow meter, 15 ... distributor with built-in crank angle sensor, 16 ... ... throttle valve opening sensor 17 ... temperature sensor, 18 ... knock sensor, 20
...... Engine body, 21 ...... Intake throttle valve, 22 ...... Fuel injection valve, 23 ...... Ignition plug, 31 ...... Knocking discrimination means, 32 ...... Advance angle correction stop instruction means.

Claims (1)

[Claims] 1. A rotational speed detecting means for detecting the rotational speed of an engine, a hot-wire type air amount detecting means for detecting an intake air amount of the engine, and an MBT in a steady state by referring to a map using these detected values as parameters. A basic advance value calculating means for obtaining a basic advance value set on the basis, an acceleration determining means for determining a sudden acceleration time, an acceleration degree calculating means for calculating an acceleration degree,
Correction amount calculating means for calculating an advance value correction amount corresponding to the degree of acceleration and a retard value correction amount corresponding to the degree of acceleration,
From the time of the sudden acceleration determination to the first predetermined time, the basic advance value is retarded by the retard value correction amount according to the acceleration degree, and from the time of the first predetermined time to the second predetermined time. Correction means for advancing the basic advance value by an advance value correction amount according to the degree of acceleration; ignition means for cutting off the primary current of the ignition coil in accordance with the corrected advance value; Knocking determination means for determining whether knocking has occurred during advance angle correction, and advance angle correction stop instruction means for instructing the correction means to stop advance angle correction when knocking occurs from this determination result. An ignition timing control device for an internal combustion engine, comprising: