JPS60178974A - Ignition timing controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To adjust reference ignition timing to an optimum position, by determining an ignition timing displacement value with the knock generation detected value of a knock sensor and according to the displacement value, phasically shifting the reference ignition timing. CONSTITUTION:A knock discriminator part 2 discriminates the presence of knock generation from an output out of a knock sensor 1. An ignition timing phase shifter 6 shifts a reference ignition timing signal outputted by a reference ignition timing signal generator 7 to lag timing control in conformity with each output voltage of a lag timing control voltage generator 31 of an ignition timing displacement value determining part 3 and a multiplier 37 and outputs the ignition signal to an ignition device 8. Thus, the reference ignition timing is adjustable to an optimum position so that an engine is most efficiently operatable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] 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 knock resistance in internal combustion engines.

In other words, gasoline with a high octane rating is less likely to cause a knock. FIG. 1 shows the ignition timing-output shaft torque characteristics of an internal combustion engine using commercially available regular gasoline and premium gasoline (having a higher octane number than regular gasoline). Point A is the knock limit point when using regular gasoline, point B is the knock limit point when using premium gasoline, and point C is the maximum output point (M
BT), and if the ignition timing is advanced beyond the knock limit point, knock will occur. According to FIG. 1, when premium gasoline is used, the ignition timing can be advanced to point B, so it is possible to improve the output shaft torque compared to when regular gasoline is used.

Figures 2 and 3 show the ignition timing characteristics of the ignition timing at points A, B, and C in Figure 1 with respect to the rotational speed (Figure 2) and load (Figure 3) of the internal combustion engine, respectively. It is a diagram.

With these characteristics, when regular gasoline and premium gasoline are mixed or used in conversion in a fuel engine, engine output can be increased by advancing the ignition timing according to the mixture ratio of regular gasoline and premium gasoline. It becomes possible to improve.

[Prior Art] By the way, in conventional ignition timing control devices, the ignition timing characteristics are set only for a predetermined gasoline, such as regular gasoline, so when premium gasoline is mixed or converted, engine output may be affected as is. I can't wait for the direction, and I have to reset the ignition timing to the advance side in some way. In particular, when using mixed gasoline, there is a knock limit point between point A and point B in Figure 1 depending on the mixing ratio of regular gasoline and premium gasoline, and the possible advance limit changes, so it is necessary to reset the ignition timing. It wasn't easy. In addition, when resetting, since the advance angle characteristics of the knock limit and MBT are different as shown in FIGS. 2 and 3, it is necessary to set the advance angle characteristics different from those for regular gasoline.

[Summary of the Invention] Therefore, the present invention has been made in view of the above points, and uses a knock sensor to detect the occurrence of knock, and based on the detected value, determines whether the gasoline in use is a mixture of regular gasoline and premium gasoline. By determining the amount of ignition timing displacement based on the ratio according to the operating condition of the engine and setting the standard ignition timing to the advanced or retarded side accordingly, it can be used even when using a mixture of ngular gasoline and premium gasoline. The purpose is to adjust the standard ignition timing to the optimal position.

[Embodiment 1 of the Invention The present invention will be explained in detail in FIG. 4. In Figure 4,
(1) is a knock sensor that is attached to the engine and detects knocking of the engine. (2) is a knock determination unit that determines whether or not a knock has occurred from the output signal of the knock sensor (1), which includes a band pass filter ■υ, a noise level detector (
b) It is composed of a comparator Iq. The input of the bandpass filter Qυ is connected to the knock sensor (1), and the output is connected to the first comparison input of the comparator I (q) and the noise level detector (A). ) is connected to the second comparator of the comparator ■@.

(3) is the ignition timing displacement determining section, which includes the retard control voltage generator, comparator nc3z, comparator n'+q, AND gate ■ (b), AND gate nc:o, integrator ■, multiplication It is composed of vessels (b). Retard control voltage generator 01
) is connected to the output of comparator Ii. Comparators 111 and 3 compare the output voltages of the retard control voltage generators 1 and 1 with predetermined voltage levels 1 and V2, respectively, and the comparison outputs are output by the AND gates 1 and 7, respectively. ) is connected to one input of the The other inputs of AND gate ■(b) and AND gate ■■ are both connected to the output of the operating region determiner (4). The integrator (7) has two inputs, a lead angle input and a retard input. Connected. Multiplier (
C) inputs the output voltage of the integrator (2) and the output voltage of the function generator (5). Operating region determiner (4) and function generator (5)
) are both pressure sensor 00 and frequency-voltage (F/V)
Input the output voltage 1 of the converter a]. pressure sensor a
0 detects the intake manifold pressure of the engine and outputs a voltage according to the operating load of the engine. The F/V converter qυ receives the ignition signal output from the ignition timing phase shifter (6), converts the frequency of the ignition signal into a voltage value, and outputs a voltage corresponding to the engine speed. Ignition timing phase shifter (6
) phase-shifts the reference ignition timing signal output from the reference ignition timing signal generator (7) according to the output voltage of the retard control voltage generator (9) and the output voltage of the multiplier (b). An ignition signal indicating the determined ignition timing is output to the ignition device (8). The ignition device (8) uses an ignition coil (9) to generate a high voltage necessary for igniting the engine.

Next, the operation of each part will be explained. Figure 5 shows the knock discrimination section (2
) shows the operation of each part. The knock sensor (1) is a generally well-known vibration acceleration sensor that is attached to the engine's cylinder block, etc., and converts the mechanical vibration of the engine into an electrical signal. Outputs a wave signal. bandpass filter) is the knock sensor (1
) from the output signal, passing only the knock-specific frequency component and suppressing noise components other than knock, as shown in Fig. 5(b).
As shown in (a), a signal with a good S/N ratio is output. The noise level detector (2) can be configured with, for example, a half-wave rectifier circuit, an averaging circuit, an amplifier circuit, etc. The iU current constant voltage level is converted by wave rectification and averaging, amplified with a predetermined amplification degree, and the output signal of the bandpass filter Qυ (Fig. 5 (b) of(
A DC voltage is output at a level higher than the noise component of (b)) and lower than the knock component. The comparison positions are the output signal of the bandpass filter 01) ((a) in Figure 5(b)) and the output J signal of the noise level detector (4) ((b) in Figure 5(b)). If no knock occurs (part C in Fig. 5), the output signal of the bandpass filter Q1 (part 5 in Fig. 5) is compared.
If (a) in Figure (b) does not exceed the output signal of the noise level detector (A) ((B) in Figure 5(b)), nothing is output, and if a knock occurs ((B) in Figure 5(b)), The output signal of the bandpass filter ■υ ((a) in Fig. 5(b)) is transferred to the output signal of the noise level detector (a) ((a) in Fig. 5(b)).
In order to exceed (b)) of b), a pulse train is output as shown in FIG. 5(c).

Therefore, the pulse train from the output of the comparator (Fig. 5 (
The occurrence of knocking can be determined based on the presence or absence of the output of C)).

FIG. 6 shows the operation of the ignition timing displacement determining section (3).

The retard control voltage generator 6υ can be configured, for example, by an integrating circuit, and when a pulse train as shown in FIG. 6(a) is output from the comparator IE3, the pulse train is integrated and the pulse train shown in FIG.
Increase the output voltage as in b). Also, comparator Ii
When no pulse train is output from the retard control voltage generator Sη, the output voltage of the retard control voltage generator Sη gradually decreases at a predetermined speed. That is, the retard control voltage generator 0υ generates in real time a retard control voltage that retards the ignition timing to the knock limit point. Then, the ignition timing phase shifter (5) receives the retard control voltage and retards the ignition timing, thereby immediately suppressing the occurrence of knock.

On the other hand, the comparator (2) and the comparator mg compare the retard control voltages output from the retard control voltage generator D at the voltage levels of V1 and V2, respectively. The relationship between Vl and v2 is, for example, the maximum value (VMAX) and minimum value (VMI) of the retard control voltage.
VMIN < V, < V2 < VMAX for V).

Comparator II C33 outputs a high level if the retard control voltage is smaller than 1, and outputs a low level if it is larger. The output operation of the comparator (-) is shown in FIG. 6(c). Furthermore, the comparator mCQ outputs a high level if the retard control voltage is larger than v2, and outputs a low level if it is smaller. The output operation of the comparator In(to) is shown in FIG. 6(d). When the high level signal from the comparator ■ (to) passes through the AND gate ■■ and is input to the lead angle input of the integrator ■, the integrator (7) outputs as shown in Figure 6(f). Gradually lower the voltage and shift to the advance side. The high level signal of comparator m63 passes through AND gate ■ (c) and is sent to integrator (7
), the output voltage is gradually increased and shifted to the retard side as shown in FIG. 6(f). When both the advance input and the retard input of the integrator (7) are at a low level, the output voltage of the integrator (7) is held.

Further, the operating range determiner (4) obtains engine operating load information from the pressure sensor Ofj and engine rotation information from the F/V converter 0], and forms an operating range map based on the load and rotation speed. Then, the operating range in which the output voltage of the integrator (to) can be shifted to the advance or retard side is set in advance in the above map, and when the engine operating state is within the set operating range, The operating region determiner (4) is shown in Fig. 6 (
A high-level signal is output as shown in e), and a low-level signal is output in other operating regions. AND gate ■(B) and AND gate ■(C) control passage of the output signals of comparator TI 03 and comparator ■Z to the integrator (7) based on the output signal of the operating region determiner (4). do.

Therefore, in the ignition timing displacement determining section (3), the integrator (
(g) When the retard control voltage output by the retard control voltage generator 0υ is smaller than ■1 and the engine is within a predetermined operating range, the output voltage is shifted to the advance side, and the retard control voltage is is v
2 and the engine is within the predetermined operating range, the output voltage is shifted to the retard side, and if the retard control voltage is between Vl and v2, or the engine is outside the predetermined operating range. In some cases, the output voltage is held.

In addition, in order to operate the engine most efficiently, it is necessary to use as much MB as possible.
A region close to T (point C in Figure 1) where knocking does not occur (
It is necessary to set the ignition timing on the retarded side of point A or point B in FIG. Therefore, when using a mixture of regular gasoline and premium gasoline, the ignition timing is controlled within the shaded areas in Figures 2 and 3, and the ignition timing characteristics are adjusted to match the MBT (point C) in other areas. Just leave it there. Therefore, this can be achieved by weighting the output voltage of the integrator (7) with a function based on the characteristics shown in FIGS. 2 and 3. It actually consists of a function generator (5) and a multiplier (a). The function generator (5) is connected to the pressure sensor Q (I and F/
The engine load (Fig. 7) and rotation speed (Fig. 8) are determined by the output voltage of V converter 01) as shown in Fig. 7 and Fig. 8.
, voltages corresponding to predetermined functions based on the characteristics shown in FIGS. 2 and 8 are generated respectively, and a voltage obtained by adding these voltages is output. Then, the multiplier holder multiplies the output voltage of the integrator (to) and the output voltage of the function generator (5). That is, the output voltage of the integrator (g) is weighted by the output voltage of the function generator (5).

Then, the point large timing phase shifter (5) outputs the reference ignition timing signal generator (7 ) can be controlled to the ignition timing that allows the engine to operate most efficiently by shifting the phase of the reference ignition timing signal output from the engine.

The ignition timing phase shifter (6) is a well-known technique in ignition timing control devices, and its explanation will be omitted here. Further, the reference ignition timing signal generator (6) outputs a reference ignition timing signal set according to the operating state of the engine, that is, the rotation speed and load. This reference ignition timing characteristic is determined, for example, by the operating characteristics of a centrifugal governor or pressure diaphragm of a distributor, or is stored in a memory in an electronic advance angle control device.

〔Effect of the invention〕

As explained above, according to the present invention, when regular gasoline and premium gasoline are used mixed or converted, knock is detected by the knock sensor, and the detection claw detects whether the standard ignition timing is advanced or retarded. It is possible to obtain the ignition timing that allows the engine to operate most efficiently by determining whether or not displacement to the corner side is necessary and by shifting the reference ignition timing in phase according to the amount of ignition timing displacement weighted according to the operating state of the engine. There is an effect that it can be done.

[Brief explanation of the drawing]

Fig. 1 is an ignition timing-output shaft torque characteristic diagram of the engine, Figs. 2 and 3 are ignition timing characteristic diagrams with respect to engine speed and load, respectively, and Fig. 4 is a block configuration diagram showing an embodiment of the present invention. , FIGS. 5 and 6 are operation explanatory diagrams in the embodiment of FIG. 4, and FIGS. 7 and 8 are output voltage characteristic diagrams of the function generator (5) with respect to engine load and rotation speed, respectively. Fourth
In the figure, (1) is a knock sensor, (2) is a knock discrimination unit, (3) is an ignition timing displacement determination unit, (4) is an operating range determiner, (5) is a function generator, and (6) is a Ignition timing phase shifter, (7) is reference ignition timing signal generator, <8 is ignition device, (9) is ignition coil, θQ is pressure sensor, αυ is F
/V converter. Agent Masuo Oiwa Figure 1 Figure 21λ1 Figure 8 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 O shield [E1 Tenyou procedure correction (voluntary) 1.8 O II ”At: 8I-118c+2 Name of the invention: Ignition timing control device for internal combustion engines 3, Relationship to the case of the person making the amendment Patent applicant address: 2-1 Marunouchi, Chiyoda-ku, Tokyo, 2-3
Name (601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4 Agent Address 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo Drawing 6 of the specification subject to amendment Contents of amendment (1) In the drawing, Figure 4 is corrected as shown in the attached sheet. Figure 4

Claims (1)

[Claims] a knock sensor for detecting knock in an internal combustion engine; a knock determination means for determining whether knock has occurred from the output of the knock sensor; a displacement determination means for determining a displacement amount of the reference ignition timing of the engine from the output of the knock determination means; An ignition timing control device for an internal combustion engine, comprising ignition timing displacement means for displacing the reference ignition timing according to the output of the displacement amount determining means, and means for correcting the displacement amount of the reference ignition timing according to the operating state of the engine.