JPH0121181Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an ignition timing control device for controlling the ignition timing of an engine to an optimum value.

(Prior art) Devices that control ignition timing according to engine operating conditions, that is, engine speed, load, etc., have been generally known.This device stores ignition timing that corresponds to each operating condition in advance. Based on this, the ignition timing is determined according to the actual driving conditions. In this case, the above memorized value for the ignition timing is determined in advance through experiments to be an appropriate value for each operating condition, but if there are variations in the characteristics of each engine or changes over time, the optimum ignition timing may not be correct. cannot be controlled.

For this reason, as shown in Japanese Patent Application Laid-Open No. 52-39038, the engine torque is detected while periodically varying the ignition timing in a specific operating state, and the torque is maximized based on the detected signal. Devices that perform feedback control on ignition timing are known. According to this device, the ignition timing is controlled to the optimum value using feedback control, but when the operating condition changes, it takes a certain amount of response time to control the ignition timing to the optimum value, so feedback control alone is not enough. There was a limit to the improvement of responsiveness.

In addition, as a countermeasure for such problems,
As shown in Publication No. 35156, the basic ignition timing is corrected by the correction amount stored in the storage means, and based on the detection of engine torque,
A control device is known that performs learning control so as to modify the above correction amount in a direction that increases engine torque. However, in this control device, although the direction of torque correction is set by checking the direction of increase in engine torque, the amount of correction is set constant regardless of the amount of torque change, so the amount of correction is If the ignition timing is small, it will take a long time to learn to reach the ignition timing that produces the maximum torque, and if the operating conditions change during that time, sufficient learning will not be possible. However, there still remains the problem that the ignition timing at which the maximum torque is produced may be exceeded, resulting in a control overshoot.

(Purpose of the invention) In view of these circumstances, the present invention aims to be able to control the ignition timing to the optimum value even when there are variations between engines and changes over time, and to improve responsiveness compared to feedback control. An object of the present invention is to provide an engine ignition timing control device that not only allows the correction control value to be corrected more quickly and more accurately than conventional learning control.

(Structure of the invention) As shown in the overall configuration diagram of FIG. It includes a detection means 3, a first storage means 4, a second storage means 5, a control means 6, a correction control value modification means 7, a torque change detection means 8, and a modification amount setting means 9. The first storage means 4 stores in advance basic control values for ignition timing in association with each operating state, and the second storage means 5 stores the following:
A correction control value for correcting the basic control value is stored. The control means 6 controls the ignition timing based on control values given by the first storage means 4 and the second storage means 5, that is, basic control according to the operating state detected by the operating state detection means 2. The ignition timing is controlled by obtaining the value and the correction control value from both the storage means 4 and 5. Further, the correction control value modifying means 7 includes the torque detecting means 3
input the output signal of
The correction control value stored in the storage means 5 is corrected. Furthermore, the torque change detection means 8 detects the state of change in torque due to correction of the correction control value, and the correction amount setting means 9 detects the state of change in torque detected by the torque change detection means 8. A correction amount for correcting the correction control value is set.

(Embodiment) Fig. 2 schematically shows an embodiment of the device of the present invention, in which 11 is a spark plug provided in each cylinder (not shown) of the engine, 12 is a distributor, and 13 is an ignition plug. These coils constitute an ignition device. The ignition timing of this ignition device is controlled by a control unit 20,
The control unit 20 includes a pressure sensor 14 that detects the pressure of an intake manifold (not shown);
Detection signals from a crank angle sensor 15 that detects the crank angle of the engine and a torque detection device 16 that detects a signal related to engine torque are input. The pressure sensor 14 detects the intake manifold pressure corresponding to the engine load as an electric signal corresponding to the pressure, and the crank angle sensor 1
5 detects when a predetermined crank angle position (for example, 60 degrees BTDC) is reached and outputs an electric signal. In addition, the torque detection device 16
For example, the distortion of the propeller shaft corresponding to the torque of the engine is converted into an electric signal corresponding to the distortion and detected, and a specific example thereof will be explained later.

The control unit 20 is formed using a microcomputer or the like, and includes a CPU 21 and a memory consisting of a ROM 22 and a RAM 23, as well as an A/D converter 24 as an auxiliary circuit for input and output processing, and an A/D converter 24 for torque signal processing. receiver 25 and peak hold circuit 26, and ignition coil 13
and an output circuit 27 for controlling the ignition signal for the ignition signal. Then, the signal from the pressure sensor 14 is sent to the CPU 21 via the A/D converter 24, and the signal from the crank angle sensor 15 is sent as an interrupt signal to the CPU 21, and the engine speed is calculated from this signal. The operating state is determined from the engine speed and the intake manifold pressure, thus forming the operating state detecting means 2 shown in FIG. Further, the detection signal from the torque detection device 16 is transmitted to the receiver 2.
5 to the peak hold circuit 26,
Here, the peak value of the torque signal is held, and this peak value is given to the CPU 21 via the A/D converter 24, and the peak hold circuit 26 is reset each time this peak value is read. .

Furthermore, the ROM 22 has a map corresponding to the first storage means 4 shown in FIG.
The ROM map divides the entire range of operating conditions determined by engine speed and intake manifold pressure into appropriate small operating ranges, and calculates the basic advance value (ignition timing) determined in advance through tests for each small operating range. (basic control value) is memorized. On the other hand, the RAM 23 has a map corresponding to the second storage means 5 shown in FIG. Ignition timing correction control values are stored for each region and can be rewritten at any time. Furthermore, programs as shown in the flowchart later and various data necessary for control are also stored in the memory.

Further, the CPU 21 performs control and calculation according to a program, and calculates a control value for ignition timing and provides a control signal to the output circuit 27, and also corrects a correction control value based on a torque signal.
When the RAM map is rewritten and this correction is made, the state of torque change is detected and the correction amount of the correction control value is set accordingly. It constitutes a value correction means 7, a torque change detection means 8, and a correction amount setting means 9.

3A and 3B show a specific example of the torque detection device 16. This detection device 16 measures the strain of the propeller shaft 17 with a strain gauge 16a, and measures the strain of the propeller shaft 17 with a transmitter 16b.
6a is generated and supplied to a transmitting antenna 16c, and the radio wave from the transmitting antenna 16c is received by a receiving antenna 16d. The radio wave received by the receiving antenna 16d is sent to the receiver 25 via the coaxial cable 16e, and is converted by the receiver 25 into an analog signal proportional to the distortion. 16f is a power source for the torque detection device 16.

The control program by the control unit 20 is shown in flowcharts as shown in FIGS. 4 and 5. That is, FIG. 4 shows the main routine, in which initialization is first performed at step _S1 , and then step _S2 .
The A/D conversion value of the manifold pressure detection signal is repeatedly input.

FIG. 5 shows the interrupt routine. This routine starts with a detection signal from the crank angle sensor 15, and first, in step _P1 , a cycle is measured from the detection signal, and in step _P2, the engine speed is calculated based on the cycle measurement. Next, in step _P3 , the basic advance angle value SA is determined according to the engine speed and intake manifold pressure at that time.
This is determined from the ROM map, and further, in step _P4 , it is determined in which operating range of the RAM map the operating state at that time is included. Next, in step _P5 , it is determined whether register I is 0 or not, and if it is not 0, it is determined in step _P6 whether register I is 1 or not. The above register I indicates whether the following process has been repeated several times in the past in the relevant operating range (specific operating range determined in step _P4 ), and at the beginning of the control, the ignition timing and Since it is not possible to check the change in torque, if I = 0, proceed directly to the steps described below without calculating the correction value.
The process moves to _P9 , and if I=1, a predetermined value ΔSA is added to the basic advance angle value SA in step _P7 , and then the process moves to step _P9 . In other cases,
That is, if the process has already been repeated two or more times, it is determined in step _P8 whether a flag Z indicating the presence or absence of learning is 1 or not. If this flag Z is 1, it means that learning has already been completed in the relevant operating range, that is, the correction control value that maximizes the torque has been calculated and written to the RAM map. , Z is not 1, it means that the above learning has not been completed. Depending on the result of this determination, the process proceeds to step _P9 through the processing of steps _PA1 to _PA3 or the processing of steps _PB1 to _PB5 .

That is, if it has not been learned yet, it is determined in step _PA1 whether flag A is 1 or not. This flag A and flag R, which will be described later, indicate the torque fluctuation situation. When the torque increases when the angle is advanced, A=1, and when the torque increases when the angle is retarded, R= 1. If A=1, then θ=SA+ΔSAAn at step _PA2
If A=1, then in step _PA3 , θ=SA−ΔSARn is calculated to obtain the ignition timing control value θ. ΔSAAn and ΔSARn in each of these arithmetic expressions were obtained in steps PC ₄ and PC ₇ , which will be described later, in the previous processing.

On the other hand, if you have already learned
At step _PB1 , it is determined whether A=1 or not, and if A=1, it is further determined at step _PB2 whether R=1 or not.
In the case of A=1 or R=1, as a correction process in case of secular change etc. after learning,
θ=SA in step PB ₃ depending on each case
+θM+ΔθAm or step
In PB ₄ , calculate θ = SA + θM - ΔθRm to find the ignition timing control value θ. In these arithmetic expressions, θM is a learned value of the correction control value already stored in the RAM map, and ΔθAm and ΔθRm are the correction values previously determined in steps PD ₄ and PD ₇ , which will be described later.
If the determinations in steps PB ₁ and PB ₂ are both NO (if flags A and R are both 0), ignition timing is controlled in step PB ₅ based on the basic ignition timing SA and the learned value θM of the RAM map. In this case, a minute value Δθ is added in order to trace the optimum value of ignition timing, that is, θ=SA+θM+Δθ
Calculate.

After finding the control value of the ignition timing in accordance with each case, the ignition timing is maintained until the ignition timing corresponding to the control value is reached in step _P9 , and then in step _P10 .
Performs output processing to cause ignition. Next, in step _P11 , the torque value is read, and then in step _P12 , the peak hold circuit is reset. Further, in step _P13 , it is determined again whether Z is 1 or not, and according to the result of the determination, steps _PC1 to _PC13 are performed.
Or perform the arithmetic processing in steps PD ₁ to _{PD 14} .

In other words, when the determination in step P ₁₃ is NO, the process is performed in step PC ₁ to calculate the torque due to the advanced ignition timing and the torque due to the retarded ignition timing of the current and previous two types of ignition timing. Calculate the torque difference ΔTQ between
Then, it is determined whether the absolute value of this torque difference ΔTQ is larger than a predetermined value _Tq1 . If this determination is YES, it is further determined in step PC ₂ whether the torque difference ΔTQ is positive or negative, and if the torque difference ΔTQ is positive, a correction value ΔSAAn in the advance angle direction is determined by calculation in steps PC ₃ and PC ₄ . After asking, step
Set flag A to 1 and R to 0 at PC ₅ , and when the torque difference ΔTQ is negative, calculate the correction value ΔSARn in the retard direction by calculations at steps PC ₆ and PC ₇ , and then set flag A at step PC ₈ . 0, R is 1. In step PC ₃ or PC ₆ above, the current correction term ΔSAn is calculated from the previous correction term ΔSAn- ₁ and the torque difference ΔTQn- ₁ using the calculation formula ΔSAn=a×|ΔTQn- ₁ |/ΔSAn- ₁ ( a is a constant), step PC ₄
Alternatively, in PC ₇ , the correction value ΔSAAn or ΔSARn is obtained by summing the correction terms up to this time. Also, the determination in step PC ₁ above is
If NO (torque difference is less than the specified value), step
Depending on whether A=1 or not based on the determination at PC ₉ , the correction value ΔSAAn or -ΔSARn is stored in the RAM map as a learning value θM at step PC ₁₀ or PC ₁₁ , and then, at step PC ₁₂ , it is determined whether or not learning is to be performed. The flag Z indicating this is set to 1, and furthermore, in step _PC13 , both flags A and R are set to 0.

On the other hand, if the determination in step _P13 is YES, the optimum ignition timing may change due to aging even after learning, so step
At PD ₁ , it is determined whether the absolute value of the torque difference ΔTQ is greater than or equal to a predetermined value Tq ₂ . If this determination is YES, it is further determined in step PD ₂ whether the torque difference ΔTQ is positive or not. If the torque difference ΔTQ is positive, a correction value ΔθAm in the advance angle direction is determined by calculation in steps PD ₃ and PD ₄ . After calculating, flag A is set to 1 and flag R is set to 0 in step _PD5 . If the torque difference ΔTQ is negative, the correction value ΔRm in the retard direction is calculated by the calculation in steps PD ₆ and PD ₇ , and then step
Set flag A to 0 and R to 1 in PD ₈ . In step PD ₃ or PD ₆ above, the current correction term Δθm
is calculated using the formula Δθm=b×|ΔTQm− ₁ |/ΔSAm− ₁ (b is a constant), and step PD ₄
Alternatively, in PD ₇ , the correction value ΔθAm or ΔθRm is obtained by summing up the correction terms up to this time.

Steps PD ₃ and PD ₆ above and steps above
PC ₃ and PC ₆ correspond to correction amount setting means, and the correction terms Δθm and ΔSAn obtained by these correspond to the correction amounts of the correction control value. The value is set according to the amount of torque change per advance amount.

If the determination at step PD ₁ is NO (the torque difference is less than the predetermined value), A=1 according to the states of flags A and R determined at step PD ₉ .
If so, in step PD ₁₁ , rewrite the RAM map using [ΔSAAn+ΔθAn] as the learning value θM, and set R=1.
If so, at step PD ₁₂ [-(ΔSAn+ΔθRn)]
After rewriting the RAM map as the learning value θM,
In these cases, set flag Z to 1 in step PD ₁₃ .
Then, in step _PD14 , flags A and R are both set to 0. If the determinations at steps PD ₉ and PD ₁₀ are both NO (both flags A and R are already 0)
), the learning value θM is not rewritten.

After performing such arithmetic processing, 1 is added to the register I, and then in step _P15 it is determined whether this register I is 3 or more, and if it is 3 or more, this register I is changed to 2. , then return to the main routine. The interrupt routine shown in FIG. 5 is repeated every time a detection signal is received from the crank angle sensor.

By controlling according to the above flowchart, the correction control value is initially determined by gradually varying the ignition timing from the basic advance value SA and checking the ignition timing at which the torque is maximum. The corrected control value is stored in the RAM map as a learned value θM, and if the optimum timing changes due to aging, the learned value θM is corrected accordingly.
RAM map is rewritten. In this way, the corrected control value is learned so that the optimum ignition timing is always obtained, and this value is stored in the RAM map and used for subsequent control, so it can respond to the operating condition even during a transient period immediately after the operating condition changes. The already learned correction control value is immediately read out from the RAM map, and the optimum ignition timing is controlled with good responsiveness.

In addition, when correcting the correction control value, check the torque difference ΔTQ, and depending on the torque fluctuation state,
Since the correction terms ΔSAn and Δθm corresponding to the correction amount of the correction control value are set as described above,
If the ignition timing at that time is far from the ignition timing at which the maximum torque is obtained and the amount of torque change is large, the correction control value is greatly revised to quickly approach the optimum ignition timing. When the amount of change becomes smaller, the amount of correction of the correction control value is reduced, and overshoot of correction can be avoided.

(Effects of the invention) As described above, the device of the present invention controls the ignition timing based on the basic control value and the correction control value that correspond to the operating state, and in particular performs correction control based on torque detection for each operating range. Remember this while modifying the value,
Since it is used for subsequent control according to each operating condition, it is possible to compensate for variations in each engine and changes over time, and control the ignition timing to the optimal value.In addition, the correction control value mentioned above can be corrected. Since the amount is set according to the amount of change in torque, the correction control value can be quickly and accurately corrected to a state where the maximum torque can be obtained, greatly improving control responsiveness and precision. It is possible.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of the device of the present invention, FIG. 2 is a block diagram showing an embodiment, FIGS. 3A and B are structural explanatory diagrams showing an example of a torque sensor, and FIGS.
The figure is a control flowchart. 11...Spark plug, 14...Pressure sensor, 1
5... Crank angle sensor, 16... Torque detection device, 20... Control unit.

Claims (1)

[Scope of utility model registration request] Operating state detection means for detecting the operating state of the engine, torque detection means for detecting a signal related to engine torque, and a first memory in which basic control values for ignition timing are stored in advance in association with each operating state. means, a second storage means in which a correction control value for correcting the basic control value is stored in association with the operating state, and ignition timing based on the control value given by the first storage means and the second storage means. a control means for controlling the above, and an output signal of the torque detection means, and correction for correcting the correction control value stored in the second storage means so that the engine torque in the current operating state is maximized. a control value modifying means; a torque change detecting means for detecting a change in torque due to the modification of the corrected control value; and a torque change detecting means for correcting the corrected control value in accordance with the change in torque detected by the torque change detecting means. An ignition timing control device for an engine, comprising: correction amount setting means for setting a correction amount.