JP2909324B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 an ignition timing control device for an internal combustion engine which is suitable for using fuels having different octane numbers.

[0002]

2. Description of the Related Art It is well known that, when an ignition timing is advanced in a high load region of an engine, an abnormal tapping sound, that is, a knocking phenomenon, occurs inside the engine. This knocking phenomenon causes unpleasant noise, and in the case of strong knocking, strong cylinder vibration occurs inside the cylinder, resulting in a partially abnormally high temperature inside the cylinder and damaging the engine. Become.

However, depending on the operating range, operating environment, fuel properties, etc., knocking does not occur even if the ignition timing is advanced, and an ignition timing (MBT: Mimamu) capable of generating the maximum torque.
spark advance for Best Torque). Therefore, an ignition timing control device for an internal combustion engine for optimizing the operation efficiency of the engine and controlling the knocking to a predetermined level or less has been conventionally proposed. This conventional ignition timing control device for an internal combustion engine detects knocking of the engine by a knock sensor attached to the engine body, and when knocking occurs, delays the ignition timing by a predetermined amount to suppress knocking, and knocking occurs. If not, control is performed to advance the ignition timing to the basic ignition timing.

However, in such a conventional ignition timing control apparatus for an internal combustion engine, a reference ignition timing characteristic is set only for a predetermined fuel, for example, regular gasoline, so that it is not possible to use another fuel, for example, premium gasoline. In the case of mixed use or conversion use, the output of the internal combustion engine cannot be improved with the reference ignition timing characteristics as it is, and the basic ignition timing must be reset to the advanced side by some method.

[0005] In particular, when a mixture of regular gasoline and premium gasoline is used, a knock limit point exists between a knock limit point when using regular gasoline and a knock limit point when using premium gasoline, depending on the mixing ratio. It was not easy to reset the reference ignition timing because the advanceable limit changed. Also, even if the reference ignition timing could be reset to the knock limit point,
Since the knock limit point fluctuates due to environmental conditions during operation of the internal combustion engine, such as temperature and humidity, and knocking easily occurs during transient operation such as acceleration of the internal combustion engine, it is not possible to avoid occurrence of knocking in the internal combustion engine. It was possible.

Therefore, in order to eliminate such a drawback of the conventional ignition timing control device for an internal combustion engine, Japanese Patent Application Laid-Open No. Sho 60-1960 discloses
There has been proposed an ignition timing control device for an internal combustion engine as described in JP-A-04777 and JP-A-2-238173. The ignition timing control device for an internal combustion engine stores a first reference ignition timing and a second reference ignition timing respectively corresponding to two fuels having different octane numbers, and detects a knocking detection amount between the two reference ignition timings. The ignition timing of the internal combustion engine is determined based on the basic ignition timing displaced by the above and the knock detection amount.

Here, for example, the first reference ignition timing is for premium gasoline, and the second reference ignition timing is for regular gasoline. Therefore, when using a mixture of premium gasoline and regular gasoline, it is possible to automatically adjust the basic ignition timing characteristics of the internal combustion engine to the optimal ignition timing, and furthermore, when the internal combustion engine is in a transient operation or under environmental conditions. The ignition timing can be retarded immediately even in the case of a sudden change.

[0008]

However, the above-mentioned Japanese Patent Application Laid-Open Nos. 60-104777 and 2-23
In the ignition timing control apparatus for an internal combustion engine as described in 8173 JP knock sensor for detecting a knocking, defective insulation, seating noises of superimposed or intake and exhaust valves of the electrical noise to the wire harness Due to mechanical noise of the engine, etc., knocking may be detected even when knocking has not occurred, that is, knocking may be erroneously detected, and the ignition timing may be retarded to a maximum extent. And the operating state at the optimum efficiency cannot be ensured, and the above-mentioned drawbacks become more remarkable because even the basic ignition timing is displaced to the ignition timing on the retard side due to the above-described knocking erroneous detection. was there.

The present invention has been made in order to solve such a problem, and the amount of retard correction by knocking is limited in accordance with the operating state of the internal combustion engine. A knocking detection state (knocking erroneous detection) and the operation state of the internal combustion engine at an optimum efficiency cannot be ensured, so that the amount of retard correction unnecessary for knocking suppression is minimized, that is, the ignition timing is set to a predetermined value.
If it is later than (regular ignition timing characteristics)
Knock erroneous detection by increasing the return speed of the angle correction amount
Minimizes engine power reduction due to unnecessary retard correction
And to obtain an ignition timing control apparatus for an internal combustion engine can be.

[0010]

According to the present invention, there is provided an ignition timing control apparatus for an internal combustion engine, comprising: knock detection means for detecting knocking of the internal combustion engine; and determination of occurrence of knocking based on an output of the knock detection means. A knock discriminating means and, based on the output of the knock discriminating means, a retard that causes the ignition timing to be corrected to a lag side when knocking has occurred, and to return the correction to an advancing side when knocking has not occurred. First determining means for determining a correction amount; and information relating to a first reference ignition timing and a second reference ignition timing corresponding to different fuel properties and set according to the operating state of the internal combustion engine. A basic ignition timing between the first reference ignition timing and the second reference ignition timing based on an output of the knock determination means or the first determination means. Second determining the displacement to displace
Determining the basic ignition timing based on the output of the second determining means, and determining the ignition timing of the internal combustion engine based on the determined basic ignition timing and the output of the first determining means. And the ignition timing of the internal combustion engine is determined by the first reference ignition timing and the second reference ignition timing.
In the reference ignition timing of any of the above, when the ignition timing is later than the reference ignition timing on the delay side, it is faster than when it is on the advance side .

[0011]

According to the present invention, the return speed of the correction in the first determining means for determining the amount of retard correction for suppressing the occurrence of knocking of the internal combustion engine is determined by the ignition timing of the internal combustion engine and the first reference ignition timing. If the second reference ignition timing is on the delayed side from any of the delayed reference ignition timings,
If there is a leading side, slow it down. Thus, the amount of retard correction unnecessary for knock suppression can be minimized, and the acceleration of the internal combustion engine is improved.

[0012]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, reference numeral 1 denotes a knock sensor which is attached to the internal combustion engine and detects knocking of the internal combustion engine. Reference numeral 2 denotes a knock determination unit which determines whether or not knocking has occurred based on the output of the knock sensor 1.

As shown in FIG. 2, for example, the knock discriminating section 2 allows only a frequency component specific to knocking to pass from the output of the knock sensor 1 and suppresses noise components other than knocking. The output of the band-pass filter 21 is converted to a DC voltage level by half-wave rectification and averaging, and further amplified at a predetermined amplification factor. A noise level detector 22 that outputs a DC voltage higher than a noise component included in the output and lower than a knock component, and a comparator 23 that compares each output of the band-pass filter 21 and the noise level detector 22
Consisting of

Reference numeral 3 denotes an output of the knock determination section 2 and a second
Is performed based on the respective outputs of the reference ignition timing characteristic storage unit and the first ignition timing calculator, and when knocking has occurred, the ignition timing is corrected to the lag side, and when knocking has not occurred. Is a retard correction amount determining unit as first determining means for determining the retard correction amount for returning the correction to the leading side and suppressing the occurrence of knocking of the internal combustion engine.

Reference numeral 4 denotes a first reference ignition timing and a second reference ignition timing which correspond to different fuel properties based on the output of the retard correction amount determiner 3 and are set in accordance with the operation state of the internal combustion engine. A basic ignition timing displacement amount determining unit, which is a second determining means for determining a displacement amount for displacing the basic ignition timing for the fuel mixed between them. Here, as an example, the first reference ignition timing is a reference ignition timing for a pre-gasoline with a high octane number, and the second reference ignition timing is a reference ignition timing for a regular gasoline with a low octane number.

As shown in FIG. 3, for example, the basic ignition timing displacement determining unit 4 compares the output of the retard correction amount determining unit 3 with a predetermined value, and outputs a retard determination output or advance according to the comparison result. A retard / advance determination circuit 41 that generates an angle determination output, a timer 42 that generates a pulse at predetermined time intervals when the retard determination is output,
A timer 43 that generates a pulse every predetermined time when the advance angle determination is output, and a pulse from the timer 42 is counted up,
An up-down counter 44 counts down the pulse from the timer 43.

Reference numerals 5 and 6 denote a first reference ignition timing characteristic storage unit and a second reference ignition timing storage unit, respectively. These reference ignition timing storage units 5 and 6 are, as shown in FIG. The data related to the first reference ignition timing and the second reference ignition timing are stored in advance at addresses determined by the rotation speed and the load.

Reference numeral 7 denotes a first ignition timing arithmetic unit comprising an interpolation arithmetic unit 71 and a subtractor 72. The interpolation arithmetic unit 71 proportionally counts the content of the count from the up / down counter 44 of the basic ignition timing displacement determining unit 4. The data is converted into a coefficient, an interpolation operation is performed between the data in the storage units 5 and 6 using the proportional coefficient, and ignition timing data is output from the data.
The output value of the retard correction amount determining unit 3 is subtracted from the ignition timing data from 1 and the ignition timing data shifted to the retard side is output as information on the basic ignition timing for the mixed fuel.

Reference numeral 8 denotes a crank angle sensor for detecting the crank rotation angle of the internal combustion engine, and 9 denotes a pressure sensor for detecting the intake air pressure of the internal combustion engine. Reference numeral 10 denotes a crank angle sensor 8 based on ignition timing data from the first ignition timing calculator 7.
Is a second ignition timing calculator that calculates an ignition timing based on the output of the second ignition timing and generates an ignition signal. The second ignition timing calculator 10 supplies an address signal corresponding to the rotation speed and load of the internal combustion engine to the storage units 5 and 6 based on the outputs of the crank angle sensor 8 and the pressure sensor 9. I have.

Reference numeral 11 denotes a switching circuit for turning on and off the power supply to the ignition coil 12 in synchronization with an ignition signal from the second ignition timing calculator 10 to generate a high voltage required for ignition of the internal combustion engine. Note that the first ignition timing calculator 7 and the second ignition timing calculator 10 determine the basic ignition timing based on the output of the basic ignition timing displacement determining unit 4, and determine the determined basic ignition timing and the delay. An ignition timing calculation means for determining the ignition timing of the internal combustion engine based on the output of the angle correction amount determination section 3 is configured.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described with reference to FIGS. Knock sensor 1 converts mechanical vibration of the internal combustion engine into an electric signal, and outputs vibration wave signal S1 as shown in FIG. This vibration wave signal S1 is supplied to the band-pass filter 21 of the knock determination unit 2, and the band-pass filter 21 passes only the frequency components specific to knocking from the vibration wave signal S1 and suppresses noise components other than knocking.
A signal S2 having a good S / N as shown in (b) is output.
The signal S2 is supplied to the noise level detector 22 and to the comparator 23.

The noise level detector 22 converts the signal S2 into a DC voltage level by half-wave rectification and averaging, further amplifies the signal S2 with a predetermined amplification factor, and as shown in FIG.
2 outputs a DC voltage signal S3 having a higher level than the noise component and a lower level than the knock component. The DC voltage signal S3 is supplied to the comparator 23 together with the signal S2, and the comparator 23 compares the two signals. When knocking does not occur (the portion indicated by the symbol C in FIG. 5), the signal S2 is converted to the DC voltage signal S3. No signal is output because the signal S2 does not exceed the threshold value. On the other hand, when knocking has occurred (the portion indicated by the symbol D in FIG. 5), the signal S2
Exceeds the DC voltage signal S3, a signal S4 of a pulse train as shown in FIG. 5 is output. Therefore, the occurrence of knocking can be determined by the presence or absence of the signal S4 from the comparator 23.

The signal S from the comparator 23 of the knock determination section 2
4 is supplied to the retard correction amount determination unit 3. The retard correction amount determining unit 3 outputs the signal S from the comparator 23 as shown in FIG.
4 is integrated, and an integrated voltage signal S5 as shown in FIG.
Get. As can be seen from FIG. 6B, the level of the integrated voltage signal S5 rises according to the pulse train when the signal S4 is output, and falls when the signal S4 is not output. Then, the integrated voltage signal S5
The A / D converter (not shown) is supplied to the first ignition timing calculator 7 after being subjected to A / D conversion, and serves as a control voltage for retarding the ignition timing by the ignition timing calculators 7 and 10 as described later.

The integrated voltage signal S5 from the retard correction amount determining section 3 is also supplied to the basic ignition timing displacement amount determining section 4. The retard / advance determination circuit 41 of the basic ignition timing displacement determining section 4 has two comparison reference values, one is a retard determination value and the other is an advance determination value. Then, the input signal S5 is compared in the retard / advance determination circuit 41 with the retard determination value and the advance determination value. Now, when the value of the integrated voltage signal S5 is equal to or greater than the retardation determination value, the mode becomes the retardation mode,
The retard / advance determination circuit 41 generates a high-level retard determination output. If the output is equal to or less than the advance determination value, the advance / deceleration mode is set, and the retard / advance determination circuit 41 performs a high-level advance determination. An output is generated, and if it is between the retardation determination value and the advancement determination value, the stop mode is set, and both the retardation determination output and the advancement determination output from the retardation / advancement determination circuit 41 become low level. .

The timer 42 generates a pulse at predetermined intervals while the retard / decision output of the retard / advance decision circuit 41 is at a high level. A pulse is generated every predetermined time while the output is at a high level. The up / down counter 44 counts up the pulse from the timer 42 and counts down the pulse from the timer 43. Therefore, when the value of the integrated voltage signal S5 of the retard correction amount determining unit 3 is larger than the retard determination value, the retard mode is set, and the count value of the up / down counter 44 is increased. Is in the advancing mode, the count value of the up / down counter 44 is decreased, and the count value of the up / down counter 44 is held between the two determination values.

The interpolation calculation unit 71 of the first ignition timing calculator 7
First converts the count value from the up / down counter 44 of the basic ignition timing displacement determining section 4 into a proportional coefficient. now,
When the count value N is input from the up / down counter 44, the count value N is divided by a preset maximum count value N _MAX from the up / down counter 44, and the result of the division is divided by a proportional coefficient K (= N / N _MAX ).

Therefore, when using premium gasoline,
Since the knock limit point is relatively on the advance side, the count value of the up / down counter 44 is substantially N = 0, and the proportional coefficient is K = 0. On the other hand, when using regular gasoline, the knock limit point is relatively on the retard side,
The count value of the up / down counter 44 is almost N = N
_MAX , and the proportional coefficient is K = 1.

When using a mixture of premium gasoline and regular gasoline, the knock limit point is located between the use of premium gasoline and the use of regular gasoline, so that the count value of the up / down counter 44 is 0 <N <N _MAX. And the proportional coefficient is 0 <K <1.
Therefore, it can be seen that the proportional coefficient K is a coefficient indicating the mixture ratio of premium gasoline and regular gasoline.

On the other hand, the reference ignition timing storage units 5 and 6 store the second
And receives an address signal corresponding to the rotational speed and load of the internal combustion engine from the ignition timing calculator 10, and outputs the ignition timing data stored at the address to the interpolation calculator 71.
Now, the ignition timing characteristics (first
Is set for premium gasoline, the ignition timing data at the above address is θ _P, and the ignition timing characteristic (second reference ignition timing) of the second reference ignition timing storage unit 6 is regular gasoline. Assuming that the ignition timing data at the above address is θ _R , the ignition timing characteristics of the first reference ignition timing storage unit 5 are the same as the ignition timing characteristics of the second reference ignition timing storage unit 6 or on the advanced side. Therefore, θ _R ≦ θ _P holds.

Therefore, the interpolation calculation unit 71 performs a proportional interpolation calculation between θ _R and θ _P using a proportional coefficient K. That is, θ _P −
Assuming that (θ _P −θ _R ) × K is calculated and the result is θ _C , θ _C is a value obtained by internally dividing K: (1−K) between θ _P and θ _R. Therefore, K = 0 when using premium gasoline
Therefore, θ _C = θ _P , and K = 1 when regular gasoline is used. Therefore, θ _C = θ _R , and 0 <K when a mixture of premium gasoline and regular gasoline is used.
Since <1, θ _R <θ _C <θ _P.

Therefore, θ _C is calculated based on the proportional coefficient K indicating the mixture ratio of premium gasoline and regular gasoline.
Since a value obtained by internally dividing the _R and theta _P, even when mixed with premium gasoline and regular gasoline, by performing the interpolation calculation, the optimal basic ignition timing in accordance with the mixing ratio of premium gasoline and regular gasoline Can be obtained.

Further, in the first ignition timing calculator 7, the subtractor 72 calculates the value after the A / D conversion of the integrated voltage signal S 5 of the retard correction amount determiner 3 from the output value θ _C of the interpolation calculator 72. Is subtracted, and the result is output to the second ignition timing calculator 10 as ignition timing data of the final basic ignition timing. That is, in order to suppress knocking that occurs at the time of transient operation of the internal combustion engine or sudden changes in environmental conditions with respect to the optimal basic ignition timing obtained by the interpolation calculation unit 72, the retard correction amount is determined by the ignition calculation from the interpolation calculation unit 72. The final basic ignition timing is obtained by subtracting from the timing data and performing retard correction.

Here, in this embodiment, the output of the first ignition timing calculator 7 is supplied to the retard correction amount determining unit 3 and
Data relating to the second reference ignition timing is supplied from the second reference ignition timing characteristic storage unit 6, and the integration return speed of the retard correction amount determination unit 3 is calculated by the first ignition timing calculator 7, ie, the final The signal S6 representing the basic ignition timing is shown in FIG.
As shown in (2), when the second reference ignition timing is on the retard side, it is advanced, and when it is on the advance side, it is delayed.

This is because the first reference ignition timing is set to the MBT ignition timing at which the maximum torque can be generated because knocking is unlikely to occur for premium gasoline with a high octane number, whereas the second reference ignition timing is set. Since the knocking is likely to occur in the case of regular gasoline with a low octane number, knocking is likely to occur in any operation state, so that the ignition timing is set to a timing at which knocking does not occur (the ignition timing is retarded from the first reference ignition timing). That is, the hatched portion in FIG. 6C is an unnecessary retard correction amount. As a result, the output of the internal combustion engine does not decrease, and its acceleration is improved. In other words, late
The ignition timing for regular is set based on the standard to increase the return speed of the angle correction amount.
Characteristics to increase the return speed.
There is no need to specially provide
It was set up to support Gyula gasoline blended gasoline
Simplification of equipment by using regular ignition timing characteristics
Can be achieved.

The second ignition timing calculator 10 uses the detection signal of the crank angle sensor 8 as a reference, and the first ignition timing calculator 7
The ignition timing is calculated based on the ignition timing data from the CPU, and an ignition signal is output. Since this is a well-known technique in an ignition timing control device, its description is omitted here.

Embodiment 2 FIG. In the above embodiment, the basic ignition timing displacement determining section 4 determines the displacement for displacing the basic ignition timing between the first reference ignition timing and the second reference ignition timing by using the retard correction amount. Although the determination is performed based on the output of the determination unit 3, the determination may be performed based on the output of the knock determination unit 2.

[0037]

As described above, according to the present invention, knock detection means for detecting knocking of an internal combustion engine, knock determination means for determining the presence or absence of knocking based on the output of the knock detection means, First, the ignition timing is corrected to the late side when knocking has occurred based on the output of the determination means, and the ignition timing is corrected to return to the advanced side when knocking has not occurred.
Determination means, and storage means for storing information relating to a first reference ignition timing and a second reference ignition timing corresponding to different fuel properties and set according to the operating state of the internal combustion engine, A second determination means for determining a displacement amount for displacing a basic ignition timing between the first reference ignition timing and the second reference ignition timing based on an output of the knock determination means or the first determination means; And determining the basic ignition timing based on the output of the second determining means, and determining the ignition timing of the internal combustion engine based on the determined basic ignition timing and the output of the first determining means. Timing calculation means, wherein the return speed of the correction in the first determination means is set to a reference ignition timing which is one of the first reference ignition timing and the second reference ignition timing which is later than the ignition timing of the internal combustion engine. Proceeds side near If there is to Ri delay side
As compared to the case where it is made faster, it is possible to automatically adjust the basic ignition timing characteristics to the optimal ignition timing in a mixed gasoline of premium gasoline and regular gasoline, and no knocking has occurred In spite of this, the knocking detection state (knocking erroneous detection) occurs and the operating state of the internal combustion engine at an optimum efficiency cannot be ensured, so that the amount of retard correction unnecessary for knocking suppression is minimized and the acceleration performance of the internal combustion engine is improved. There is an effect that can be.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating an example of a knock determination unit used in FIG.

FIG. 3 is a block diagram illustrating an example of a basic ignition timing displacement amount determination unit used in FIG. 1;

FIG. 4 is a diagram for explaining the operation of one embodiment of the present invention;

FIG. 5 is a signal waveform diagram for describing the operation of one embodiment of the present invention.

FIG. 6 is a signal waveform diagram for describing the operation of one embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 knock sensor 2 knock determination unit 3 retard correction amount determination unit 4 basic ignition timing displacement amount determination unit 5 first reference ignition timing characteristic storage unit 6 second reference ignition timing characteristic storage unit 7 first ignition timing calculator Reference Signs List 8 crank angle sensor 9 pressure sensor 10 second ignition timing calculator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02P 5/152

Claims (1)

(57) [Claims] 1. Knock detection means for detecting knocking of an internal combustion engine; knock determination means for determining whether knocking has occurred based on an output of the knock detection means; and knocking occurrence based on an output of the knock determination means. If it is determined that the ignition timing is corrected to the delay side, and if knocking does not occur, the ignition timing is corrected to the advanced side. Storage means for storing information relating to a first reference ignition timing and a second reference ignition timing corresponding to and set in accordance with an operating state of the internal combustion engine; and the knock determination means or the first determination means. Second determining means for determining a displacement amount for displacing the basic ignition timing between the first reference ignition timing and the second reference ignition timing based on the output of Determining the basic ignition timing based on the output of the determining means, and ignition timing calculating means for determining the ignition timing of the internal combustion engine based on the determined basic ignition timing and the output of the first determining means. The ignition timing of the internal combustion engine is delayed from the first reference ignition timing or the second reference ignition timing which is later than the reference ignition timing. An ignition timing control device for an internal combustion engine, wherein the ignition timing is made faster than in the case of being on the leading side.