JPH0615862B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition timing control device for an internal combustion engine.

It is well known that the octane number of gasoline has a strong correlation with the resistance to knocking in internal combustion engines. That is, gasoline with a higher octane number is more difficult to knock. FIG. 1 shows the ignition timing-output shaft torque characteristics in an internal combustion engine in the case of using commercially available Regula gasoline and premium gasoline (having a higher octane number than Regura gasoline). Point A is the knock limit point when using regular gasoline, and point B is the knock limit point when using premium gasoline. When the ignition timing is advanced beyond the knock limit point, knock occurs. According to Fig. 1,
Since the ignition timing can be advanced to point B when using premium gasoline, the output shaft torque can be improved compared to when using regular gasoline. FIG. 2 is an ignition timing characteristic diagram showing the ignition timing at points A and B in FIG. 1 with respect to the rotational speed of the internal combustion engine.

In an internal combustion engine having such characteristics, when converting from regular gasoline to premium gasoline, the output of the engine can be improved by advancing the ignition timing by a predetermined angle.

[Prior art]

By the way, in the conventional ignition timing control device, since the ignition timing characteristic is set only for a predetermined gasoline, for example, Regulaura gasoline, it is not possible to expect an improvement in the output of the engine as it is when using premium gasoline. I had to reset the ignition timing to the advanced side. Further, since the knock limit points at points A and B in FIG. 1 vary depending on environmental conditions during engine operation, such as temperature and humidity, when the ignition timing is set at points A or B, environmental conditions There is a risk of knocking due to the change of.

[Outline of Invention]

The present invention has been made with respect to the above point, detects the occurrence of knock using a knock sensor, determines whether the gasoline in use is Regulaura gasoline or premium gasoline by the detected value, the determination Depending on the result, by setting the ignition timing to the advance side or the retard side,
While automatically switching the reference ignition timing according to the type of gasoline, if a knock occurs at the reference ignition timing before or after the switching, the ignition timing is retarded according to the knock occurrence, It is intended to suppress the occurrence of knocks.

Example of Invention

FIG. 3 shows a first embodiment of the present invention. In FIG. 3, (1) is a knock sensor which is attached to the engine and detects the knock of the engine. Reference numeral (2) is a knock discriminating section for discriminating the presence or absence of the occurrence of a knock from the output signal of the knock sensor (1). The band pass filter (21) and the noise level detector (2
2) and a comparator (23). Band pass filter
The input of (21) is connected to the knock sensor (1), and the output is connected to one comparison input of the comparator (23) and the noise level detector (22). The output of the noise level detector (22) is connected to the other comparison input of the comparator (23). (3) is an ignition timing switching determination unit that calculates from the output of the knock determination unit (2) and determines whether or not ignition timing switching is required.
1), a counter (32) and a timer (33). The input of the pulse generator (31) is connected to the output of the comparator (23), and the output is connected to the counting input of the counter (32). In addition, the timer (3
3) is connected to the reset input of the counter (32). (4) is a storage unit that stores the mode of the output of the ignition timing switching determination unit (3) (output of the counter (32)), and the flip-flop F / F (4
1) and the reset circuit (42). The set input of the flip-flop (41) is connected to the output of the counter (32), and the reset input is connected to the reset circuit (42). (9) is a retard control voltage generator, the input of which is connected to the output of the comparator (23). (10) is a synthesizing unit, which includes an adder (101) and a timer (10
It consists of 2). The adder (101) has two input terminals, one of which is connected to the output of the flip-flop (41),
The other is connected to the output of the retard control voltage generator (9). The timer (102) has an input connected to the output of the flip-flop (41) and an output connected to the reset terminal of the retard control voltage generator (9). On the other hand, (5) is a reference ignition timing signal generator for generating a reference ignition timing signal of the engine, and (6) is an output signal of the reference ignition timing signal generator (5) output from the synthesizing section (10) (addition). It is an ignition timing phase shifter that shifts the phase according to the output of the device (101). (7) is a switching circuit that synchronizes with the output signal of the ignition timing phase shifter (6) to intermittently energize the ignition coil (8) to generate a high voltage necessary for ignition of the internal combustion engine.

Next, the operation of each part will be described. Fig. 4 shows the knock determination section (2)
The operation of each part of is shown. The knock sensor (1) is a generally well-known vibration acceleration sensor, which is attached to a cylinder block or the like of an engine, converts mechanical vibration of the engine into an electric signal, and as shown in FIG. Output a signal. The band pass filter (21) passes only the frequency component peculiar to the knock from the output signal of the knock sensor (1) to suppress the noise components other than the knock, and as shown in (a) of FIG. 4 (b), S Outputs a good signal with / N. The noise level detector (22) can be composed of, for example, a half-wave rectifying circuit, an averaging circuit, an amplifying circuit, etc., and outputs the output signal of the bandpass filter (21) ((a) in FIG. 4 (b)). Converted to DC voltage level by half-wave rectification and averaging, amplified with a predetermined amplification degree, and
As shown in (b) of FIG. (B), it is higher than the noise component of the output signal of the bandpass filter (21) ((a) of FIG. 4 (b)),
It outputs a DC voltage at a level lower than the knock component. The comparator (23) is an output signal of the band pass filter (21) (Fig. 4).
When (a) in (b) is compared with the output signal of the noise level detector (22) ((b) in FIG. 4 (b)), if no knock occurs (C in FIG. 4), Nothing occurs because the output signal of the band pass filter (21) ((a) in FIG. 4 (b)) does not exceed the output signal of the noise level detector (22) ((b) in FIG. 4 (b)). When no output occurs and a knock occurs (D in Fig. 4), the output signal of the bandpass filter (21) ((a) in Fig. 4 (b)) is output from the noise level detector (22). Signal (of Fig. 4 (b)
(B)) is exceeded, a pulse train is output as shown in FIG. 4 (c). Therefore, the occurrence of the knock can be discriminated by the presence / absence of the output of the pulse train (FIG. 4 (c)) from the output of the comparator (23).

FIG. 5 shows the operation of each unit other than the knock discriminating unit (2). The pulse generator (31) outputs the pulse train (5th pulse) output from the comparator (23).
Pulses are output as shown in FIG. 5 (d) with respect to FIG. That is, the pulse generator (31) outputs one pulse for each knock occurrence for one ignition. Pulse Generator (31)
Output pulses are counted by a counter (32), and the counting contents are shown in FIG. 5 (e). The timer (33) outputs a pulse every predetermined time as shown in FIG. 5 (f), and the pulse resets the count value of the counter (32) to zero. The output of the counter (32) is the counter as shown in Fig. 5 (g).
When the count value of (32) exceeds a predetermined value (count value 3 in FIG. 5), the level becomes high. That is, the ignition timing switching determination unit
(3) outputs a high level signal when a predetermined number of knocks occur within a predetermined time. This is to calculate the occurrence rate of knock by the above method, and as a result, determine whether or not ignition timing switching is necessary.

The reset circuit (42) outputs a high level pulse when the engine is started, and FIG. 5 (h) shows the output pulse of the reset circuit (42). Also, the flip-flop (41) is set (flip-flop) when the output of the counter (32) is high level.
The output of (41) becomes high level. ) And the reset circuit (4
The output of 2) is reset when the output is high level. The output operation of the flip-flop (41) is shown in FIG. 5 (i). First,
When the engine is started, the flip-flop (41) is connected to the reset circuit (4
It is reset by 2) and the output goes low. That is, the mode (advance mode) in which the ignition timing is not switched is set. Then, when the output of the counter (32) outputs a high level as shown in FIG. 5 (g), the output of the flip-flop (41) switches to a high level. That is, the ignition timing switching mode (retard mode) is set. After that, the retard mode is maintained until the engine stops. Further, as a matter of course, when the output of the counter (32) does not output high level after the engine is started, the output of the flip-flop (41) remains low level (advance mode).

Further, the retard control voltage generator (9) is composed of, for example, an integrating circuit, and when the comparator (23) outputs a pulse train as shown in FIG. 5 (c), the pulse train is integrated and integrated. Increase the output voltage as shown in (j). When the pulse train is not output from the comparator (23), the output of the retard control voltage generator (9) gradually decreases at a predetermined speed. Then, a retard control voltage for retarding the ignition timing to the knock limit point is generated in real time to suppress the occurrence of knock.

The synthesizer (10) is flip-flop (41) by the adder (101).
And the output of the retard control voltage generator (9) are added and combined. The output of the adder (101) is shown in FIG. Further, the timer (102) outputs a pulse as shown in FIG. 5 (l) for a predetermined time when the output of the flip-flop (41) is reversed from the low level (advance mode) to the high level (retard mode). This pulse is input to the reset terminal of the retard control voltage generator (9), and the output voltage of the retard control voltage generator (9) is shown in FIG. 5 (j).
Reset to zero level like. Therefore, the adder (10
The output of 1) is as shown by the solid line in Fig. 5 (k). If the output of the retard control voltage generator (9) is added as it is when the flip-flop (41) is reversed to the retard side, the retard angle becomes excessive as shown by the broken line in FIG. The sex becomes worse. Therefore, as described above, when the ignition timing is switched to the retard side, the output of the retard control voltage generator (9) is reset to the zero level so as not to be added, in order to prevent an excessive retard.

On the other hand, the ignition timing phase shifter (6) controls the phase of the input signal to the retard side according to the control voltage. This ignition timing phase shifter (6) is a well-known technique in the ignition timing control device, and its explanation is omitted here. The reference ignition timing signal generator (5) detects the rotation of the crankshaft of the engine and outputs a signal indicating the timing to ignite, and is, for example, an ignition signal generator incorporated in the distributor. The ignition timing characteristic of the reference ignition timing signal generator (5) is set according to the engine speed and load, and the engine speed is set to the characteristic shown in FIG. 2 (B). The output signal of the reference ignition timing signal generator (5) is shown in FIG. 5 (m) and is input to the ignition timing phase shifter (6). And
The output of the adder (101) is input to the control voltage input of the ignition timing phase shifter (6), and the output signal of the reference ignition timing signal generator (5) shifts according to the output voltage of the adder (101). Be shared. The output signal of the ignition timing phase shifter (6) is shown in FIG. Now
Flip Flop (41) output is low level (advance mode)
When the output of the retard control voltage generator (9) is at zero level, the ignition timing phase shifter (6) does not perform the transfer operation, and its output is the reference ignition timing signal generator (5). The output signal appears as it is, and as a result, the ignition timing characteristic in actual ignition remains as shown in FIG. 2 (B). Further, when a knock occurs in the engine, the ignition timing switching determination unit (3) determines that switching is necessary, and the output of the flip-flop (41) switches to a high level (retard mode), the ignition timing phase shifter. As shown in (n) of FIG. 5, (6) retards the output signal (FIG. 5 (m)) of the reference ignition timing signal generator (5) by a predetermined angle. for that reason,
The ignition timing characteristic in actual ignition is as shown in FIG. Further, if knocking occurs even after switching the ignition timing, the angle is further retarded than in FIG. 2 (A).

Therefore, when using premium gasoline, Fig. 2
In the ignition timing characteristic shown in (B), since there is no knock that requires switching of the reference ignition timing, the ignition timing does not switch and the characteristic shown in FIG. 2 (B) remains.
In addition, Fig. 2 shows the case of using Regulaura gasoline.
In the ignition timing characteristic of (B), since it is a region where knock occurs, the engine causes knock. A knock is detected by the knock discriminating unit (2), the ignition timing switching discriminating unit (3), the storage unit (4) and the ignition timing phase shifter (6), and the ignition timing is switched to the retard side. The ignition timing is fixed to the ignition timing characteristic of FIG. If knocking occurs even at the ignition timing, the ignition timing is delayed to the knock limit point by the retard control voltage generator (9), the synthesizing section (10) and the ignition timing phase shifter (6). Horn.

By the way, in the first embodiment, the switching of the reference ignition signal causes the retarded phase shift according to the output of the storage unit (4), but two reference ignition timing signals having different ignition timing characteristics are stored in the storage unit. You may switch according to the output of (4). This will be described below as a second embodiment.

FIG. 6 shows a block diagram of the second embodiment of the present invention. 6, the same reference numerals as in FIG. 3 indicate the same parts. (10) is a first ignition timing characteristic storage unit (hereinafter referred to as ROM (10)), and (11) is a second ignition timing characteristic storage unit (hereinafter referred to as ROM (1)).
1)), and as shown in FIGS. 7 (A) and 7 (B), the memory address (address) determined by the engine speed and load.
The ignition timing data is stored in each. Fig. 7
(A) is the data of ROM (10), which is set for Regula-Yula gasoline. Also, FIG. 7 (B) is the data of ROM (11), which is set for premium gasoline, and is shown in FIG.
It is located on the advance side of (A). Reference numeral (12) is a data selector, which inputs the data of the ROM (10) and the ROM (11) and the output mode of the storage unit (4), and outputs RO according to the output mode of the storage unit (4).
Outputs data from M (10) or ROM (11). (13) is the first
The timer has the same function as the timer (102) in the above embodiment and is similarly connected. (14) is an A / D converter that converts the output voltage of the delay angle control voltage generator (9) into a digital amount, and (15) is an A / D converter from the output value of the data selector (12).
It is a subtractor that subtracts the output value of the converter (14). (16) is a crank angle sensor that detects the crank rotation angle of the engine, and (17) is a pressure sensor that detects the intake air pressure of the engine. (18) is an ignition timing calculator and a crank angle sensor
The engine speed is calculated from the output signal of (16) and the pressure sensor
The load condition of the engine is detected from (17), and the value determined by the rotational speed and load is converted into an address value and the address value is output to the ROM (10) and ROM (11). Also,
The ignition timing calculator (18) reads the output data of the subtractor (15), calculates the ignition timing from the output data of the subtractor (15) based on the output signal of the crank angle sensor (16), and switches the ignition signal. Output to circuit (7).

Next, the operation of the second embodiment will be described. Knock judgment unit
(2), the ignition timing switching determination section (3), the storage section (4), and the retard control voltage generator (9) are the same as those in the first embodiment.
If you now use premium gasoline, the storage unit (4)
Output remains low (advance mode). Therefore, the data selector (12) outputs the data of the ROM (11) in the low level output mode of the storage unit (4). That is, the 7th
The ignition timing characteristic of FIG. 6B is set as the reference ignition timing. And
If no knock occurs at the ignition timing, the outputs of the retard control voltage generator (9) and the A / D converter (14) are at zero level, so the output of the subtractor (15) is the data selector ( 12)
The output data of is output to the ignition timing calculator (18) as it is. When the ignition timing switching determination unit (3) generates a knock that does not require switching, the retard control voltage generator (9) outputs a voltage due to the knock and the A / D converter
(14) converts the output voltage of the retard control voltage generator (9) into a digital amount, and the subtractor (15) converts the output value of the data selector (12) into the output value of the A / D converter (14). Subtract. Therefore, the data output from the subtractor (15) is the data (θ _B ) obtained by subtracting the angle (θ _R ) corresponding to the output of the retard control voltage generator (9) from the data (θ _B ) in the ROM (11). _B -θ _R ). Then, the ignition timing calculator (18) outputs an ignition signal delayed by an angle θ _R corresponding to the occurrence of the knock from the reference ignition timing shown by the characteristic in FIG. 7 (B), and suppresses the occurrence of the knock.

In addition, if you use reguiura gasoline,
The output of (4) becomes a high level (retard mode), and the data selector (12) outputs the data of the ROM (10), that is, the data based on the ignition timing characteristic of FIG. 7 (A). Then, as in the case of using the above premium gasoline, the ignition timing calculator (18) reads the data (θ _A ) of the ROM (10) if the knock does not occur, and if the knock occurs, the data of θ _A −θ _R is read. Read.

Thus, according to the second embodiment, the reference ignition timing characteristics are switched to different ignition timing characteristics (Figs. 7 (A) and (B)) when premium gasoline is used and when regular gasoline is used. If a knock occurs in these reference ignition timing characteristics, the ignition signal is controlled so as to be retarded with respect to the reference ignition timing in order to suppress the occurrence of the knock.

〔The invention's effect〕

As described above, according to the present invention, when reguilla gasoline and premium gasoline are converted and used, the presence or absence of knock is detected by the knock sensor, and the number of knock occurrences in the predetermined section is calculated based on this, and Whether it is regular gasoline or premium gasoline is determined based on whether or not the number of knock occurrences is equal to or greater than a predetermined value, and it is possible to prevent an erroneous determination due to a sudden knock occurrence and perform an accurate determination. Further, the determination result is stored in the storage means, and the ignition timing is switched according to the output thereof. The ignition timing is not switched until the storage means is reset, and stable ignition timing control is performed. It can be performed.

Further, there is an effect that even if a knock occurs due to a change in environmental conditions during engine operation before and after ignition timing switching, the ignition timing can be retarded to the knock limit point in real time.

Further, by resetting the retard control voltage generator (9) when the ignition timing is switched to the retard side, it is possible to prevent excessive retard.

[Brief description of drawings]

1 is an engine output shaft torque characteristic diagram, FIG. 2 is an engine ignition timing characteristic diagram, FIG. 3 is a block configuration diagram showing a first embodiment of the present invention, and FIG. 4 is a knock determination unit (2 5) is an operation timing chart of the ignition timing switching determination unit (3), the storage unit (4), the retard control voltage generator (9), the synthesizing unit (10), and the ignition timing phase shifter.
FIG. 6 is a block diagram showing the operation of each part of (6), FIG. 6 is a block diagram showing the second embodiment of the present invention, and FIG. 7 is an ignition timing characteristic diagram in the second embodiment. (1) is a knock sensor, (2) is a knock discriminating unit, (3) is an ignition timing switching discriminating unit, (4) is a storage unit, (5) is a reference ignition timing signal generator, and (6) is an ignition timing phase shift. , (7) is a switching circuit, (8) is an ignition coil, (9) is a retard control voltage generator,
(10) is a synthesis section. The same reference numerals in the drawings indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiro Danno 1 Uzumasa Tatsumi-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture Mitsubishi Motors Corporation (72) Inventor Toshio Iwata 840 Chiyoda-cho, Himeji-shi, Hyogo Mitsubishi Electric Corporation Company Himeji Works (72) Inventor Atsushi Ueda 840 Chiyoda-cho, Himeji City, Hyogo Prefecture Mitsubishi Electric Co., Ltd. Himeji Works (56) Reference JP 58-143169 (JP, A) JP 56-48700 JP , B1)

Claims (4)

[Claims] 1. A knock sensor for detecting knock of an internal combustion engine, a knock discriminating means for discriminating the presence or absence of knock from the output of the knock sensor, and the number of knock occurring in a predetermined section is calculated from the output of the knock discriminating means. Ignition timing switching determination means for determining whether or not ignition timing switching is necessary depending on whether the number of times of knocking is a predetermined value or more, storage means for storing the output of the ignition timing switching determination means, calculation from the output of the knock determination means, and knocking A retard control voltage generating means for generating a voltage according to the generation, and a reference ignition timing of the engine according to the output of the storage means are switched to another ignition timing characteristic preset according to the parameter of the engine and the retard timing is changed. An ignition timing control device for an internal combustion engine, comprising: ignition timing calculation means for retarding ignition timing according to an output of an angle control voltage generation means. 2. The ignition timing calculation means releases the ignition timing retard control by the output of the retard control voltage generation means when the output of the storage means is shifted to the retard side. An ignition timing control device for an internal combustion engine according to claim 1. 3. The ignition timing control device for an internal combustion engine according to claim 1 or 2, wherein the switching of the reference ignition timing in the ignition timing calculation means is performed by a phase shift of the reference ignition timing. . 4. A method according to claim 1, wherein the reference ignition timing is switched by the ignition timing control calculation means by switching two reference ignition timings having different ignition timing characteristics. Ignition timing control device for internal combustion engine.