JPS60222563A - Ignition timing controlling device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of excessive knocking while prevent an output-torque variation shock by shiftingly controlling a reference ignition timing so as to be gradually changed to the lag side or to the lead side in accordance with the occurring condition of knocking. CONSTITUTION:The signal of a knock sensor 1 enters a lag angle controlling voltage generator 3 through a knock judging part 2, and its lag angle controlling signal is outputted to a phase shifter 9 through an adder 7 and, together with a reference ignition timing signal from a generator 8, controls ignition timing. The signal is also inputted into a reference ignition timing shifting judging part 4, and a comparator 41 makes H output when it is above a reference voltage V1 for premium gasoline while a comparator 42 makes H output when it is below V2 for regular gasoline, to output a lead-angle or a lag-angle mode signal (m) to an adder 7 through AND's 43, 44, a flip-flop 46, a delay circuit 5, depending on the operating condition from an operating area judging device 45, shiftingly controlling actual ignition timing to be gradually varied.

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, and more particularly to a device that controls ignition timing based on the octane number of gasoline, which is the fuel thereof.

[Prior art]

It is known that the octane number of gasoline has a strong correlation with the knock resistance of an internal combustion engine. That is, the higher the octane number of gasoline used, the less likely the internal combustion engine will knock.

Figure 1 shows the ignition timing versus output torque characteristics of an internal combustion engine using regular gasoline and premium gasoline (higher octane than regular gasoline). Point A is the knock limit point when regular gasoline is used. , B are the knock limit points when premium gasoline is used, and in each case, if the ignition timing is advanced beyond the knock limit point, knock will occur, and as the ignition timing is advanced, the knock will become larger. As is clear from FIG. 1, since the ignition timing can be advanced to point B when using premium gasoline, it is possible to improve the output torque compared to when using regular gasoline.

FIGS. 2 and 8 show ignition timing characteristics showing the ignition timing at these knock limit points A and B with respect to the rotational speed and load of the internal combustion engine, respectively. As shown in these figures, if the rotation speed or load is the same, the ignition timing can be advanced when using premium gasoline.

As described above, when the gasoline used in an internal combustion engine is converted to regular gasoline and premium gasoline or mixed, it is possible to improve the engine output by adjusting the ignition timing according to the type of gasoline.

By the way, the characteristics of conventional ignition timing control devices used in internal heat engines of automobiles currently on sale are based on regular gasoline, so premium gasoline cannot simply be used in such engines. However, the output of the engine will not improve, and there will be no benefit from using premium gasoline unless you somehow change the ignition timing to the advanced side.

In addition, by using knock control technology that detects engine knock and controls the ignition timing to the knock occurrence limit point, the basic ignition timing characteristics (for example, the first
It is conceivable to perform appropriate knock control when regular gasoline is used, and to retard the ignition timing to point A in FIG. 1, based on point B in the figure. However, in this case, the ignition timing retard control width (the angular width between points A and B in Figure 1) is wide, so if knock occurs in the engine, the ignition timing will change from point B to point A in Figure 1. There was a problem in that a large knock occurred during the control.

[Summary of the invention]

The present invention has been made with attention to the above points, and uses a knock sensor to detect knock occurring in the engine, and determine whether the gasoline used is regular gasoline based on the knock occurrence situation.
Determine whether it is premium gasoline, switch the ignition timing advance characteristic, set the ignition timing characteristic corresponding to the gasoline used, and reduce the control angle width of knock control as appropriate to prevent knock from occurring. It also prevents sudden changes in the ignition timing during switching control of each ignition timing characteristic, prevents sudden fluctuations in engine output, and prevents excessive knocking during switching. The aim is to prevent this from occurring.

[Embodiments of the invention]

FIG. 4 shows an embodiment of the present invention. In Figure 4, (
1) is a knock sensor that is attached to the engine and detects the knock status of the engine, and (2) is a knock discrimination unit that discriminates the knock signal from the detection signal of the knock sensor (1), which includes a band pass filter (2) and noise level detection. It consists of a comparator (a) and a comparator. Here the bandpass filter (goods)
passes only the frequency of the band corresponding to the knock signal component of the detection signal of the knock sensor (1), and its output is input to the first comparison input of the comparator (E) and the noise level detector). The output of the noise level detector (2) is input to the second comparison input of the comparator. (3) is a retard control voltage generator that generates a retard control voltage in response to the output of the comparator (e). (4) is a reference ignition timing switching determination unit that determines switching of the reference advance characteristic of ignition timing, and this is composed of two comparators f411 and f42° and two AND gates f4.
1441, an operating region determiner @51 flip-flop 14[11, and an initialization circuit ←η. The comparators (411, @2 are used to compare the respective reference voltages v1 or 2 with the output of the retard control voltage generator (3), and these outputs are connected to AND gates (4:1 or -), respectively. The operating region determiner 00 uses a pressure sensor (described later).
6) and the output of the phase shifter (9), determine the operating range of the engine,
This output is input to the AND gate decoy and (441. The flip-flop (461) has a set input, a reset input, and a preset input, respectively.
(b), and the output of the initialization circuit (471) are input.The initialization circuit outputs a preset pulse, for example, when starting the engine.(5) is a delay circuit that delays the output of the flip-flop. The pressure sensor (6) detects the intake pipe pressure of the engine and converts it into an electrical signal.The pressure sensor (7) detects the retard control voltage from the retard control voltage generator (3) and the output of the delay circuit (5). The adder (8) is a reference ignition timing signal generator that generates a reference ignition timing signal that gives the reference ignition timing, and the phase shifter (9) is a reference ignition timing signal generator (8).
) is a phase shifter that shifts the reference ignition timing signal from the adder (7) to the delay side according to the signal voltage from the adder (7), and QO is a phase shifter (9
) The engine is ignited and operated with the high voltage generated by one ignition coil 0υ using a switch circuit that turns on and off the energization of the ignition coil 0υ in response to the output of the engine.

FIGS. 5 and 6 show operational waveforms of the FIG. 4 section.

The operation will be explained below.

The knock sensor (1) is, for example, a type that detects vibration acceleration, is attached to the cylinder block of an engine, and converts mechanical vibrations (knock and noise vibrations) of the engine into electrical signals. This detection signal is shown in FIG.
The bandpass filter Qυ selects the knock-specific frequency component (the frequency component of the signal that appears with the occurrence of knock) from the detection signal, and suppresses noise components other than the knock signal. The noise level detector (support) is composed of, for example, a half-wave rectifier circuit, an averaging circuit, an amplifier circuit, etc., and a band-pass filter shown in (a) of Fig. 5(b). The output signal of (2) is converted into a DC voltage by half-wave rectification and averaging, and amplified by an amplifier to output the DC voltage shown in (B) of Fig. 5(b). The left side shows the case where no knock occurs in the engine, and the right side shows the case where knock occurs.The output of the noise level detector (2) shown in (b) of FIG. 5(b) is as follows. The output (noise signal other than the knock signal (Nl) of the band pass filter when no knock occurs in the engine shown in the left part of (a) in Figure 5 (b))
The bandpass filter Q is larger when knocking occurs in the engine as shown in the right part of (a) in Figure 5(b).
The voltage is smaller than the knock signal (8) output from p.

The outputs of these bandpass filters aI) (Fig. 5 (bl
(a)) and the output (to the noise level detector) (Fig. 5(a))
The comparison mode that performs the voltage comparison with (b)) of b) outputs a pulse signal only in response to a knock signal when knock occurs in the engine. The output of this comparator (goods) is shown in Figure 6 (
cl, that is, the pulse signal from the comparator (e) corresponds to a knock signal generated in the engine.

Next, explanation will be given using FIG. 6. Here, we show the operating waveforms of the engine under eight different operating conditions. The cases where regular gasoline is used in standard ignition timing settings for gasoline are shown.

The retard control voltage generator (3) is composed of, for example, an integrating circuit, and generates a signal as shown in FIG. 6 (d) based on the pulse signal (FIG. 6 (C)) from the comparator (2). A retard control voltage is generated.This retard control voltage falls at a predetermined speed when no pulse signal is input from the comparator (to).Also, the retard control voltage is input to the comparator 1411 and H2. At the same time, the signal is inputted to the phase shifter (9) via the adder (7) and used for ignition timing control.

Comparator i4+i, (42 is the retard control voltage from the retard control voltage generator (3) and the reference voltage ■1 or V2, respectively.
The comparator (411 sets its output to a high level as shown in Fig. 6 if the retard control voltage (Fig. 6 (d)) is higher than the reference voltage 71), and The comparator is connected so that the retard control voltage (Fig. 6(d)) is the reference voltage v.
If it is less than 2, the output is set to a high level as shown in FIG. 6(g). Here, the reference voltage V, , V2 is Vl>V
, is in the relationship.

The operating range determiner detects the engine's intake pipe pressure and converts it into an electrical signal, detects the load condition of the engine from the pressure signal from the pressure sensor (6), and detects the engine's load condition from the pressure signal from the first phase shifter (9). Detects the engine speed from the ignition signal.

The operating state of the engine is determined from this operating information.

For example, as shown in Fig. 7, when setting the reference ignition timing for premium gasoline, when premium gasoline is used, the retard control voltage (retard control voltage generator) required to retard the reference ignition timing to the knock limit point is used. Let α be the operating condition in which the output of (3)) is less than or equal to ■, and the retard control voltage necessary to retard the reference ignition timing to the knock limit point is 71 or more when regular gasoline is used. On the other hand, as shown in Fig. 8, in the standard ignition timing setting compatible with regular gasoline, β is the operating condition in which the retard control voltage is 2 or less when premium gasoline is used, and 72 or more when regular gasoline is used. .

The operating range in which these operating conditions α and β are compatible is determined by the operating range determiner, and the operating state of the engine is determined by the operating conditions α and β.
When both conditions are compatible, the output of the first operating region determiner becomes a high level. Therefore, an AND gate that outputs a logical product signal of the output of the comparator @υ and the output of the operating range determiner 4←
The output of Hiro is at a high level only when using regular gasoline with standard ignition timing setting corresponding to premium gasoline.On the other hand, the output of comparator
The output of the AND gate, which outputs an AND signal with the output of , will be at a high level only when premium gasoline is used in the standard ignition timing setting compatible with regular gasoline. That is, when premium gasoline is used in the standard ignition timing setting for regular gasoline, or when regular gasoline is used in the standard ignition timing setting for premium gasoline, the operating state of the engine is such that the above operating conditions α and β are met. In a compatible state, the output of AND gate (b) or AND gate (4:1) is output in the central part of Figure 6 (k) or Figure 6 (j), respectively.
) is limited to a high level as shown on the right side.

The flip-flop is set when the output of AND gate (4) becomes high level, and reset when the output of AND gate (2) becomes high level. Initialization circuit (4) (Figure 6 (
1)), and this preset pulse presets the flip-flop to the set state (the flip-flop (8) is
) is set, its output is high; when reset, its output is low. As above 7
The lip-flop system first starts with the initialization circuit 1 when starting the engine.
It is set by the preset pulse from 4η (Fig. 6 (1)) and the output is set to a high level (retard mode compatible with regular gasoline). If the engine is operated in this state, premium gasoline will be used. If so, the knock occurring in the engine will be below the predetermined value, and the retard control voltage generator (
The output of 3) is less than ■2 (center part of Figure 6(d))
, the output of the AND gate H becomes a high level in the above-mentioned predetermined operation region (the region where the above-mentioned conditions α and β are compatible) (Fig. 6 (k)
), the flip-flop is reset and its output is set to a low level (advanced angle mode compatible with premium gasoline) (center of FIG. 6(m)). On the other hand, when regular gasoline is used with the ignition timing setting compatible with premium gasoline (advanced angle mode where the flip-flop is reset), the knock that occurs in the engine exceeds the specified level, and the retard control voltage is generated. The output of the device (3) becomes 71 or more (the right part of Fig. 6 (d)), and the output of the AND gate (4 rises) becomes a high level in the above-mentioned predetermined operating region (the right part of Fig. 6 (j)). ), the flip-flop number is set, and its output is set to a high level (retard mode compatible with regular gasoline) (right side of Fig. 6(m)).The output of this flip-flop decoy is sent to the adder (7). )
The signal is then input to the phase shifter (9).

The reference ignition timing signal generator (8) outputs a reference ignition timing signal with advance side ignition timing characteristics corresponding to premium gasoline, which is set according to the engine operating state (rotational speed and load). This is, for example, a signal generated by an ignition signal generator built into the power distributor.

The phase shifter (9) controls the phase of the reference ignition timing signal to be delayed in time according to the voltage from the adder (7), and outputs the signal. Therefore, when the output of the flip 70 knob (4!) becomes a high level, the ignition timing characteristics are changed to the delayed side, which is delayed by an angle corresponding to that level.The switch circuitry is controlled by the output of the phase shifter (9). Correspondingly, the energization of the ignition coil Q is interrupted to generate a high voltage for the ignition reservoir.Therefore, the generation timing of the high voltage (ignition timing) is determined by the adder (7) input to the phase shifter (9). It is controlled by the output, that is, it is controlled to change in response to the high/low level of the output of the flip-flop circle, and is further controlled in response to the output voltage of the retard control voltage generator (3).

By the way, regarding ignition timing switching control such as 1 or more,
Premium gasoline is used when the standard ignition timing is set to a later characteristic for regular gasoline.
When switching the reference ignition timing to the advance side compatible with premium gasoline, that is, when flip-flop 4 is changed from the set state to the reset state, the output of this flip-flop (a) instantly activates the phase shifter (9). When the amount of phase shift is reduced, the ignition timing instantly switches from the delayed ignition timing for regular gasoline to the advanced ignition timing for premium gasoline, which can prevent shocks caused by rapid output fluctuations or sudden knocks. There is a risk that the engine will enter the area and cause an excessive knock that can even damage the engine. Therefore, in the present invention, the output of the flip-flop 1461 (FIG. 6(m)) is input to the delay circuit (5), and a control signal with a delay that gradually changes the level when changing from a high level to a low level is generated. (FIG. 6(n)) is input to the phase shifter (9), and when switching the reference ignition timing from the delayed side to the advanced side, the reference ignition timing is gradually shifted to the advanced side. This is an effective control for engine characteristics, so for example, a digital ignition system that calculates ignition timing by counting angles and mils, or a digital ignition system that calculates ignition timing based on a predetermined period of time from repeated charging and discharging of a capacitor. It can be applied regardless of the type of ignition device such as an analog type ignition device.

However, in principle, in the analog ignition system described above, differential characteristics appear when controlling the ignition timing, so it is desirable to have a larger delay than in the case of the digital ignition system, and in this method, the ignition timing Differential characteristics also appear when controlling the timing from the advanced side to the retarded side, causing the ignition timing to be excessively retarded, resulting in an increase in the exhaust gas temperature of the engine and a decrease in the output torque.This increase in the exhaust temperature is a great harm to the engine. This is a big problem especially when a supercharger is installed. Therefore, in the analog ignition system, as shown in FIG. 9, it is preferable to provide a delay even when controlling the ignition timing from the advanced side to the delayed side. In other words, a delay is also given when the output of the flip-flop series changes from a low level to a high level.

On the other hand, this delay circuit (5) can be easily realized using a well-known (4) time constant circuit or the like.

〔Effect of the invention〕

As explained above, according to the present invention, by detecting knock occurring in the engine and controlling the reference ignition timing to be delayed or advanced depending on the occurrence situation, regular gasoline or premium gasoline can be used. In the ignition system that is set to the corresponding ignition timing characteristics, switching control is performed so that the actual ignition timing gradually changes when switching between the delayed side and the advanced side of the reference ignition timing.
This prevents the ignition timing from suddenly entering the knock region during switching, prevents excessive knock from occurring in the engine, and prevents shocks due to ignition timing fluctuations.

In addition, when the ignition timing control calculation is configured using an analog method that calculates the ignition timing by calculating a predetermined time by repeating the charging and discharging of a capacitor, it prevents excessive ignition timing changes when switching the reference ignition timing, and increases the output. This provides an excellent effect of preventing torque fluctuation shock.

[Brief explanation of drawings]

Figures 1, 2, 8, 7 and 8 are characteristic diagrams of the engine, Figure 4 is a block circuit diagram of an embodiment of the present invention, and Figures 5, 6 and 9. The figure shows an operation waveform diagram of each part in FIG. 4. In the figure, 5 (1) is a knock sensor 1 (2) which is a knock discrimination section;
(3) is a retard control voltage generator, (4) is a reference ignition timing switching determination section, (5) is a delay circuit, (6) is a pressure sensor, (
7) is the adder 1 (8) is the reference ignition timing signal generator, (9
) represents a phase shifter, αO represents a switch circuit, and (b) represents an ignition coil. Figure 1 Figure 2 Figure 3 Figure 7 Figure 8 Figure 9 Procedural amendment (voluntary) 5981B Showa year, month, day 2, name of invention, ignition timing control device for internal combustion engine 3, person making the amendment To Representative Katayuni, Section 4, Agent 5, Column 6, Detailed explanation of the invention in the specification subject to amendment, Contents of amendment (1) The specification is corrected as follows.

Claims (1)

[Claims] A knock sensor that is attached to the engine and generates an electric signal corresponding to the knock vibration and noise vibration of the engine, a knock signal discrimination means that discriminates the knock signal component from the electric signal, and a reference based on the output of the knock signal discrimination means. An ignition timing switching determination means for determining switching of the ignition timing characteristic; an ignition timing characteristic selected by switching between two preset ignition timing characteristics, an advanced side and a delayed side, based on a switching output of the ignition timing change determination means; an ignition timing control means for causing the engine to ignite at an ignition timing according to the above, and a means for changing and controlling the ignition timing so that the actual ignition timing is gradually changed when switching between the two ignition timing characteristics. Ignition timing control device.