JPH03237266A - Knocking control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the aggravation of operability at the normal time and the advancement of knocking at the time of quick acceleration by stopping knocking learning on the spark advance/delay correction quantity of ignition timing at the specified quick acceleration state, and stopping the use of the learning value in the setting of ignition timing. CONSTITUTION:Ignition timing is controlled by a means C upon the lapse of time from the reference signal generated time by a sensor A in a specified crank angle position to the ignition timing set by a means B in an internal combustion engine. The spark advance/delay correction quantity of a ignition timing is learned/updated by a means E according to the existence of knocking detected by a sensor D. In such a device, the specified quick acceleration state is detected by a means F. In the quick acceleration state, the above-mentioned learning is stopped, as well as the use of the spark advance/delay correction quantity in the setting of the ignition timing is stopped, whereas in any other state than this, learning is controlled by a means G so as to perform the above- mentioned learning as well as to execute the use of the spark advance/delay correction quantity in the setting of the ignition timing.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention includes a crank angle sensor that generates a reference signal at a predetermined crank angle position of an engine, and measures the time from the generation of the reference signal to the set ignition timing. is estimated based on at least the calculated value of the generation cycle of the reference signal, and the ignition signal is output when the calculated time elapses from the generation of the reference signal, and the ignition timing is advanced or retarded according to the engine operating state. The present invention relates to a knocking control device for an internal combustion engine that has a learning function that updates and learns a correction amount depending on whether or not knocking occurs.

<Conventional technology> Conventionally, electronically controlled ignition control devices for internal combustion engines set the ignition timing (crank angle position) according to the engine operating state, and control the ignition by outputting an ignition signal at this timing. For this purpose, a reference signal is generated at a predetermined crank angle position of each cylinder, and at the same time, a reference signal is generated at a crank angle of 1.
Or, by using a crank angle sensor that generates a unit signal every 2 degrees and measuring the number of unit signals generated after the reference signal for each cylinder is generated to determine the crank angle position, ignition is performed at the set ignition timing. It is common to have the

However, a crank angle sensor having a unit signal generation function requires high accuracy and is expensive.

Therefore, using a crank angle sensor that generates only a reference signal and a cylinder discrimination signal, when the reference signal is generated, the generation cycle of the reference signal (time since the previous reference signal) is calculated, and based on this cycle, the generation cycle of the reference signal is calculated. A time control system has been proposed that estimates and calculates the time until the ignition timing and outputs an ignition signal when this time elapses to cause ignition. Incidentally, Japanese Unexamined Patent Publication No. 61-286584 discloses a time control system, although it is intended for fail-safe purposes.

In addition, using the above-mentioned crank angle sensor, in addition to the generation cycle of the reference signal, the rate of change in the generation cycle (deviation between the latest generation cycle and the previous generation cycle) is calculated, and these generation cycles and the rate of change are calculated. In response to this, attempts have also been made to perform ignition timing control by performing estimation calculations with higher accuracy, taking into account changes in crank angular velocity.

On the other hand, in setting the ignition timing in the ignition timing control, knocking occurring in the engine is detected by a knocking sensor, and the basic ignition timing, which is set according to the engine rotational speed and load, is advanced depending on whether or not knocking occurs. Retard angle correction is generally performed. That is, when knocking does not occur, the engine angle is corrected little by little in the advance direction, and when knocking occurs, control is repeated to retard the angle relatively largely to appropriately control the knocking level.

In recent years, the advance/retard angle correction amount is corrected and learned for each engine operating state classified by engine rotational speed and load, and then stored, and this learned advance/retard angle correction amount is used to correct the advance/retard angle. It has also become common to carry out so-called knock learning in parallel, in which the ignition timing is quickly controlled to the optimum knocking level by setting the ignition timing.

<Problem to be Solved by the Invention> By the way, in a conventional knocking control device that employs a method of setting ignition tie softening using the above-mentioned crank angle sensor and simultaneously setting ignition timing while performing the above-mentioned knocking learning, It had problems as described below.

In other words, when accelerating suddenly, especially when accelerating suddenly from a low speed, immediately after the start of acceleration, the increase in combustion energy lags behind the increase in compression energy due to the increase in air volume, and as shown in Fig. 5, the increase in combustion energy is temporarily delayed. Rotation speed decreases. In that case, in the method of time-controlling the ignition timing using the crank angle sensor, due to the delay in response to the decrease in rotational speed,
This may cause an error in the advance direction and cause knocking.

At that time, a correction is made in the retard direction to suppress knocking, and at the same time, this retard correction retards the amount of advance/retard correction in the same operating state divided by engine speed and load. You will have to study and make corrections.

When such learning is performed, an error in the advance angle direction due to the crank angle sensor will not occur, or even if it occurs, the error will be small at times other than during sudden acceleration, so the learned advance/retard angle correction amount will not be used during sudden acceleration. As a result, the ignition timing is erroneously controlled in the retarded direction, resulting in a delay in controlling the optimum ignition timing. in particular,
Retard control causes insufficient output, etc.

On the other hand, it is also possible to set the ignition timing during sudden acceleration using the advance/retard angle correction amount that is constantly learned, and if the correction amount is learned in the advance direction, the error in the advance direction can be As a result of the expansion, the occurrence of knocking is encouraged.

The present invention was made in view of such conventional problems, and when controlling ignition timing during sudden acceleration and other times,
An object of the present invention is to provide a knocking control device for an internal combustion engine that can maintain good knocking control performance by avoiding the adverse effects of learning.

<Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention is provided with a crank angle sensor that generates a reference signal at a predetermined crank angle position of the engine, and from the time when the reference signal is generated, the ignition timing setting means is set. ignition timing control means that estimates and calculates the time until the ignition timing set by at least based on the calculated value of the generation cycle of the reference signal, and outputs the ignition signal when the calculated time elapses from the generation of the reference signal. In a knocking control device for an internal combustion engine, the knocking control device includes a knocking learning means that updates and learns an ignition timing advance/retardation correction amount according to an engine operating state according to the presence or absence of knocking detected by the knocking detection means. Sudden acceleration detection means detects a predetermined sudden acceleration state, and in the predetermined sudden acceleration state, stops learning by the knocking learning means and adjusts the learned advance/retardation correction amount of the knocking learning means when setting the ignition timing. A learning control means that stops use in a predetermined rapid acceleration state, and otherwise causes the knocking learning means to perform learning and uses the learned advance/retardation angle correction amount of the knocking learning means when setting the ignition timing. The bottom of the tank is provided with .

(Function) When a predetermined sudden acceleration state is detected by the sudden acceleration detection means, the learning control means uses the advance/retardation correction amount stored in the knocking learning means when setting the ignition timing by the ignition timing setting means. At the same time, the learning in the knocking learning means, that is, the correction and updating of the ignition timing advance/retardation correction amount in the same operating range divided by engine speed, load, etc. is stopped.

Further, when the engine is not in a predetermined rapid acceleration state, the learning control means uses the learned advance/retard angle correction amount when setting the ignition timing, and also performs knocking learning.

The ignition timing control means estimates and calculates the time from the generation of the reference signal to the set ignition timing based on at least the generation cycle of the reference signal generated from the crank angle sensor, and calculates the time from the generation of the reference signal to the set ignition timing. Outputs an ignition signal when the time elapses.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2 showing the tank bottom of one embodiment, an internal combustion engine 1 includes an air cleaner 2. Intake duct 3. Air is drawn in via the throttle chamber 4 and the intake manifold 5.

An air flow meter 6 is provided in the intake duct 3 to detect the intake air flow rate Q. Throttle chamber 4
is provided with a throttle valve 7 that operates in conjunction with an accelerator pedal (not shown) to control the intake air flow rate Q. The throttle valve 7 is set to its opening TVO! A throttle sensor 15 is attached that is detected by a meter.

The intake manifold 5 is provided with an electromagnetic fuel injection valve 8 for each cylinder, and injects fuel into the intake manifold 5 that is pressure-fed from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator.

The fuel injection amount is controlled by a control unit 9 with a built-in microcomputer based on the intake air flow rate Q detected by the air flow meter 6 and the distributor 1.
The basic fuel injection amount T,
The final fuel injection amount T+ is calculated by correcting this basic fuel injection amount T based on the cooling water temperature, etc., and a drive pulse signal with a pulse width corresponding to this fuel injection amount T+ is sent to the engine. By outputting the fuel to the fuel injection valve 8 in synchronization with the rotation, the required amount of fuel is injected and supplied to the engine 1.

Here, the crank angle sensor lO outputs a reference signal REF that rises at a position of 75 degrees before the compression top dead center of each cylinder and falls at a position of 5 degrees before the compression top dead center, as shown in FIG. , outputs a small pulse cylinder discrimination signal close to a specific reference signal.

The detection of the engine rotational speed is calculated as the reciprocal of the generation cycle of the reference signal REF position (time from the previous generation of the reference signal REF).

Further, each cylinder of the engine 1 is provided with an ignition plug 11, to which a voltage generated by an ignition coil 12 is constantly applied via a distributor 13, thereby igniting a spark and creating an air-fuel mixture. ignite and burn. here,
The ignition coil 12 has an attached power transistor 12
The timing at which high voltage is generated is controlled via a. Therefore, the ignition timing (ignition advance value) ADV is controlled by controlling the OFF timing of the power transistor 12a by the ignition timing control from the control unit 9. In this case, the reference signal REF from the crank angle sensor 10 Based on the calculation formula described later with reference to FIG.
The time to ADVT is estimated using the formula described later, and the ignition signal (power transistor 1
2a OFF signal) is output.

ADVT-TREFL X (75-ADV)/110
-K X (TREFO-TREF)
-ADV)/180・・・(1) The first term on the right side of the above equation (1) is a value proportional to the reference signal REF generation cycle, that is, a term indicating the estimated time assuming that the rotation speed is constant. , the second term is a value obtained by multiplying the rate of change of the reference signal REF generation period by a proportionality constant K, and when the rotational speed increases, the ignition timing is advanced according to the magnitude of the increase rate, that is, in the advance direction. When the rotational speed decreases, the ignition timing is retarded, that is, corrected in the retard direction, depending on the magnitude of the decrease rate.

The control unit 9 retrieves the basic ignition timing ADV corresponding to the operating condition from a map stored in the ROM for each of a plurality of operating regions divided by the basic fuel injection amount T and engine rotational speed N. At the same time, in a predetermined knocking detection operation range, the presence or absence of knocking is determined based on a detection signal from a knocking sensor 14, which is a knocking detection means that detects knocking using a piezoelectric element, and advance/retardation correction is performed. Set the final ignition timing ^DV.

Further, in the knocking detection region, except for the predetermined rapid acceleration driving state, the advance/retard angle correction amount is stored for each driving region classified in the same manner as the basic ignition time XJADV map, and the ignition When setting the timing ADV,
After performing so-called knocking learning in which a new advance/retard angle correction amount is memorized and updated based on the advance/retard angle correction amount based on the presence or absence of knocking, the basic ignition timing ADVo is advanced or retarded based on the learned advance/retard angle correction amount. Correct and set. Further, in the predetermined rapid acceleration driving condition layer, the basic ignition timing ADVe is directly corrected for advance/retardation to set the ignition timing ADV without using the learned advance/retardation correction amount for the driving region; At this time, the advance/retard angle correction amount is not modified, updated, or learned by the advance/retard angle correction amount.

Here, the advance/retard angle control based on the knocking detection of the ignition timing ADV performed by the control unit 9 is performed in the 41st! This will be explained according to the program shown in the flowchart of I.

The program shown in the flowchart of FIG. 4 is executed every time the reference signal REF of the crank angle sensor 10 is output for each reference crank angle (every 180° in a four-cylinder internal combustion engine).

In step (denoted as S in the figure) l, the reference signal RE
A timer T, which measures the time ADDT from when F is input to the ignition timing calculated as described later, is reset to zero.

In step 2, it is determined whether the area is a region where knocking is likely to occur and knocking detection is required.

If it is determined that it is not in the knocking detection required area, proceed to step 3 and set the ignition timing ADV in a separate routine (BGJ).
The engine rotation speed N and load (e.g. basic fuel injection amount TP)
Basic ignition timing ADV found from.

Set it as is.

Further, if it is determined in step 2 that the knocking detection request area is reached, the process proceeds to step 4, and it is determined whether or not knocking has occurred based on the detection signal ksi of the knocking sensor 14.

When it is determined that knocking has occurred, the process proceeds to step 5, where a retard angle correction amount of α° is set.

Next, the process proceeds to step 6, in which it is determined based on the rate of change of the throttle valve opening detected by the throttle sensor 15, etc. whether the rapid acceleration state is greater than a predetermined value.

When it is determined that the rapid acceleration state is higher than a predetermined value, the process proceeds to step 7, and it is determined whether the rotational speed is in a low rotational speed region lower than a predetermined value.

When it is determined that the rotation speed is in the low rotational speed region below the predetermined value, the process proceeds to step 8, and the ignition timing ^DV is set to a value obtained by subtracting the retardation correction amount α from the basic ignition timing ADV obtained in the same manner as described above.

Also, the determination in step 6 or step 7 is N.

In this case, the process proceeds to step 9, and the current operating range is determined from the learning map of the advance/retard angle correction amount X stored in the RAM in each operating range divided by engine speed N and basic fuel injection amount T Search the advance/retard angle correction amount X stored in , and update the advance/retard angle correction amount X in the same area of the map by the value obtained by subtracting the advance angle correction amount α from the learned advance/retard angle correction amount Remember. However, in this knocking learning, the advance/retard angle correction amount
The past weighted average value and the current correction amount may be appropriately weighted and weighted averaged (the same applies to step 15 described later).

Next, the process proceeds to step 10, where the ignition timing ADV is set by adding the learned advance/retardation correction amount X to the basic ignition timing aovs.

Further, when it is determined in step 4 that knocking does not occur, the process proceeds to step 11, where an advance angle correction amount of β° is set.

Then, in the same way as when knocking occurs, step 1
2. In step 13, the rapid acceleration and low rotational speed regions are determined, and if both are YES, proceed to step 14,
Ignition timing ADV is the basic ignition timing ADV.

Set the lead angle correction amount by adding the lead angle correction amount β to After updating in Step 16, the ignition timing ADV is set to a value obtained by adding the advance/retard correction amount X to the basic ignition timing ADVo.

In this way, step 3. 8.10.14.16
After setting the ignition timing ADV in either step 1
Proceed to step 7, and use the above equation (1) to calculate the reference signal REF.
Time from the time of occurrence to the above set ignition timing ADV^
Estimate and calculate DVT.

In step 18, it is determined whether the measured value of the timer T has reached the calculated time ADVT, and the process waits until it reaches the time ADVT, and when it has reached the time, the process proceeds to step 19 and outputs an ignition signal.

If knocking control is performed using such ignition timing control, learning of the advance/retard angle correction amount is stopped during sudden acceleration from a low rotation speed, and use of the advance/retard angle correction amount learned when setting the ignition timing is stopped. .

This makes it possible to prevent the retardation correction due to the error in the advance direction of the estimated time ADVT from affecting the learned value and to prevent the deterioration of drivability due to the incorrect retardation correction during steady driving. It is possible to prevent knocking from occurring due to use.

In FIG. 4, the throttle sensor 15 and crank angle sensor 10, which are detection mechanisms for determining sudden acceleration and low rotational speed in step 6.7, constitute sudden acceleration detection means, and steps 9 and 15 The function of step 6.7 constitutes the knocking learning means, and the determination in step 6.7 controls the execution and stopping of knocking learning and the use and non-use of the learned advance/retardation correction amount. configuring the control means; step 3. The functions of step 8.10.14.16 constitute ignition timing setting means, and step 17.18.
19 functions constitute an ignition timing control means.

<Effects of the Invention> As explained above, according to the present invention, knocking learning is stopped in a predetermined rapid acceleration state, and the learning value is not used for setting the ignition timing, so that the time-controlled crank angle sensor It is possible to prevent deterioration of drivability due to incorrect retardation correction during steady driving, and also to prevent the occurrence of knocking during sudden acceleration by using the learned advance/retardation correction amount.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a block diagram showing the configuration of the present invention.
FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 4 is a timing chart for explaining calculation of estimated time until ignition timing based on a signal from a crank angle sensor used in this embodiment. 5 is a flowchart showing the knocking control of the same embodiment as above, and FIG. 5 is a diagram showing the state at the time of rapid acceleration from a low rotational speed. 1...II section 9...Control unit 10
... Crank angle sensor 14 ... Knocking sensor 15 ... Throttle sensor

Claims (1)

[Claims] A crank angle sensor is provided that generates a reference signal at a predetermined crank angle position of the engine, and the time from the generation of the reference signal to the ignition timing set by the ignition timing setting means is determined based on at least a calculated value of the generation cycle of the reference signal. Estimate calculation is performed using
Knocking is provided with an ignition timing control means that outputs an ignition signal when the calculated time elapses from the generation of the reference signal, and a knocking detection means detects the advance/retardation correction amount of the ignition timing according to the engine operating state. A knocking control device for an internal combustion engine is provided with a knocking learning means that updates and learns depending on whether or not knocking has occurred. In addition to stopping the learning, when setting the ignition timing, the use of the learned advance/retardation correction amount by the knocking learning means is stopped in a predetermined rapid acceleration state, and in other cases, the learning by the knocking learning means is executed and the ignition is started. 1. A knocking control device for an internal combustion engine, comprising: learning control means for causing the advance/retardation angle correction amount learned by the knocking learning means to be used when setting the timing.