JPS60222564A - 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 through a pulse generator in accordance with the occurring condition of knocking. CONSTITUTION:The signal of a knock sensor 1 enters a lagangle controlling voltage generator 3 through a knock judging part 2. A controlling voltage from the generator 3 is outputted to a phase shifter 8 through an adder 6, and, together with a reference ignition timing signal from a generator 7, controls ignition timing. The controlling voltage is also inputted in 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. And, a lead-angle or a lag-angle mode signal (m) is outputted to the adder 6 through a flip-flop 46 in accordance with a signal from an operating area judging device 45, while it is also given to a lag-angle controlling voltage generator 3 through a pulse generator 20, to shiftingly control 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 rotational speed or load is the same, the ignition timing can be advanced when using pre- or mium 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.

Therefore, the characteristics of the conventional ignition timing control devices used in the internal combustion engines of automobiles currently sold are based on regular gasoline, so premium gasoline and gasoline are not suitable for such engines. Merely using premium gasoline will not improve the engine's output.1 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 and retard the ignition timing to point A in FIG. 1 when regular gasoline is used, based on point B in the figure. However, in this case, since the ignition timing retard control width (the angular width between points A and B in Figure 1) is large, when knock occurs in the engine, the ignition timing is controlled from point B to point A in Figure 1. There was a problem in that a large knock occurred during the process.

[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. In addition, when switching the standard ignition timing characteristic from a retard setting (when using regular gasoline) to an advance setting (when using premium gasoline), it suppresses sudden changes in ignition timing. This is to control so that excessive knocking does not occur.

[Embodiments of the invention]

FIG. 4 shows an embodiment of the present invention.
1) is attached to the engine and causes knock vibration of the engine.

Knock sensor (2) detects noise vibration, and (2) is a knock discrimination unit that discriminates a knock signal from the detection signal of knock sensor (1), which includes a band pass filter (2), a noise level detector (2), and a comparator (2 ). Here, the detection signal of the knock sensor (1) is input to the band pass filter (2), and the output of the band pass filter (c) is sent to the first comparison input of the comparator (to) and the noise level detector).
is input. The output of the noise level detector (sub) is input to the second comparison input of the comparison speech. (3) is the subject of ``a retard control voltage generator that generates a retard control voltage in response to the output of a comparator (product) or a pulse generator (e) to be described later. (4) is a reference ignition timing switching determination section that determines switching of the reference advance characteristic of ignition timing, and this is a two-piece O comparison n14.
'J-*U% 2 pieces)' gate ka,
f441.

Operating region determiner 146. It is composed of a flip-flop 1 and an initialization circuit 1η. Comparator (4u, f4
2 is each reference voltage V! (2) and the output of the retard control voltage generator (3) are compared, and these outputs are input to the AND gate 6 or -, respectively. The operating range determiner determines the operating range of the engine from the outputs of the pressure sensor (5) and phase shifter (8), which will be described later, and this output is input to the AND gates @:l) and -. flip flop (a)
has set manual input, reset input, and preset input,
And gate @3 for each. , 1441. and the output of the initialization circuit θη are input manually. The initialization circuit 1471 outputs a preset pulse when starting the engine, for example.

The pressure sensor (5) detects the intake pipe pressure of the engine and outputs i! Convert the air signal. (No. 6 is an adder that adds the retard control voltage from the retard control voltage generator (3) and the output of the flip-flop (E), and (7) generates a reference ignition timing signal that gives the reference ignition timing. Reference ignition timing signal generator, phase shifter (8
The phase shifter 1 (9) that shifts the phase of the reference ignition timing signal from the reference ignition timing signal generator (7) to the delay side according to the signal voltage from the adder (6) is the phase shifter (8). The engine is ignited and operated using the high voltage generated by the ignition coil QO. The pulse generator 翺 generates pulses in response to the fall of the output of the flip-flop (A).

FIGS. 5 and 6 show operating waveforms of each part of the fourth section.

The operation will be explained below.

The knock sensor (1) is, for example, a type that detects vibration acceleration, is attached to a cylinder block of an engine, etc., and converts mechanical vibrations (knock and noise vibration) of the engine into electrical signals. This detection signal is shown in FIG. 5(a).
The band-pass filter (2) selects a knock-specific frequency component (frequency component of a signal that appears with the occurrence of knock) from the detection signal, and suppresses noise components other than the knock signal, as shown in FIG. 6(b). Outputs the signal shown in b). The noise level detector (support) is composed of, for example, a half-wave rectifier circuit, an averaging circuit, an amplifier circuit, etc., as shown in Figure 5(b).
The output signal of the band-pass filter (b) shown in (a) of Figure 5 is converted into a DC voltage by half-wave rectification and averaging, and amplified by an amplifier to produce the DC voltage shown in (b) of Figure 5(b). Output. In FIG. 5, the left side of the figure shows the case where knocking does not occur in the engine, and the right side shows the case where knocking occurs. The output of the noise level detector (2) shown in (b) of Fig. 5 (bl) is the output of the band pass filter when no knock occurs in the engine shown in the left part of (a) of Fig. 5 (b). Deer output (noise signals other than knock signals (N
1) The knock signal of the output of Fig. 6 (for the bandpass filter when knock occurs in the engine shown in the right part of (a) of BL) is larger than 81.The voltage is smaller than 81.These bands Output of pass filter (2) (Fig. 5 (
b) (a)) and noise level detection I! ! The comparison stem that performs a voltage comparison with the output of (a) ((b) in FIG. 6(b)) outputs a pulse signal only in response to a knock signal when knock occurs in the engine. The output of this comparator (2) is shown in FIG. 6(C). That is, the pulse signal from the comparator (2) 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 receives a pulse signal from the comparator (2) or the pulse generator (Fig. 6(C), Fig. 6(n)). Based on this, a retard control voltage as shown in FIG. 6(d) is generated.

The retard control voltage decreases at a predetermined speed if no pulse signal is input from the comparator or from the pulse generator. The retard control voltage is input to the comparator @II, -2 and at the same time is applied to the phase shifter (8) via the adder (6), where it is used for ignition timing control.

The comparator @υg area respectively receives the retard control voltage from the retard control voltage generator (8) and the reference voltage v1 or V! 1 comparator @phantom is the above retard control voltage (Fig. 6 (
If d)) is higher than the reference voltage 71, its output is shown in Figure 6 (
f), and on the other hand, the comparator (■) sets the retard control voltage (FIG. 6(d)) to the reference voltage V! If it is below, the output is set to a high level as shown in Figure 6 (g). Here, the reference voltages Vl and V have a relationship of Vs)%.

The operating range determiner detects the engine's intake pipe pressure and converts it into an electrical signal to detect the load condition of the engine from the pressure signal generated by the pressure sensor (5).

The engine speed is detected from the ignition signal from (8).

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. (3) is less than vI, and α is the operating condition under which the retard control voltage required 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, when premium gasoline is used, the retard control voltage is ■! The operating conditions under which the value is 72 or more when regular gasoline is used are defined as β.

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 are compatible, the output of the operating range determiner becomes a high level. Therefore, the AND gate 0 that outputs the AND signal of the output of the comparator @phantom and the output of the operating range judger
The output of the ignition timing is high only when regular gasoline is used with the standard ignition timing setting corresponding to premium gasoline.On the other hand, the AND gate outputs a logical product signal of the output of the comparator @2 and the output of the operating range judge. The output of the circle is
The standard ignition timing for regular gasoline is at a high level only when premium gasoline is used in the setting. In other words, 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 condition of the engine is such that the above operating conditions α and β are met. Both are in a compatible state, and the output of AND gate @Soku or AND gate @ Shun is the 6th, respectively.
The level is limited to a high level as shown in the center part of Figure 6(k) or the right part of Figure 6(j).

The flip-flop (A) is set when the output of the AND gate (C) goes high, and is reset when the output of the AND gate (C) goes high. Initialization circuit 14
For example, η is the preset pulse (
This preset pulse generates the signal shown in Fig. 6 (1), and the flip-flop ■ is preset to the set state (the left side of Fig. 6 (m)). Its output will be high, and when reset, its output will be low. As described above, the flip-flop t4fA first receives the preset pulse from the initialization circuit 1471 (Fig.
) '), and the output is set to a high level (retard mode compatible with regular gasoline). If the engine is operated in this state, it will cause a knock in the engine if premium gasoline is used. becomes below a predetermined value, and the output of the retard control voltage generator (3) becomes ■! It is as follows (Fig. 6 (
d), the output of the AND gate becomes a high level in the above predetermined operating region (the region where the above conditions α and β are compatible) (Fig. 6 (center of kl), and the flip-flop system is reset. The output is set to a low level (advance mode compatible with premium gasoline) (center part of Figure 16 (m)), while the ignition timing is set to a low level (advance mode compatible with premium gasoline).
If regular gasoline is used (advance mode in which the flip-flop is reset), the knock occurring in the engine will exceed a predetermined level, and the output of the retard control voltage generator (3) will exceed 71 ( In the above-mentioned predetermined operating region, the output of the AND gate (44 becomes high level (right part of Fig. 6 (j)), the flip-flop number 1 is set, and its output is The output of this flip-flop is set to a high level (retard mode compatible with regular gasoline) (right side of Fig. 6 (m)).The output of this flip-flop is input to the phase shifter (8) via the adder (6). At the same time, it is input to the pulse generator).

A reference ignition timing signal generator (7) outputs a reference ignition timing signal having an advanced ignition timing characteristic corresponding to premium gasoline, which is set according to the operating state (rotational speed and load) of the engine. This is, for example, a signal generated by an ignition signal generator built into the power distributor.

The phase shifter (8) controls the phase of the reference ignition timing signal to be delayed in time according to the voltage from the adder (6), and outputs the signal. Therefore, when the output of the flip-flop becomes high level, the ignition timing characteristic is changed to a delayed side ignition timing characteristic delayed by an angle corresponding to that level. The switch circuit (9) turns on and off the energization of the ignition coil QO in response to the output of the phase shifter (8), and generates a high voltage for ignition. Therefore, the high voltage generation timing (ignition timing) is controlled by the output of the adder (6) inputted to the phase shifter (8), that is, it is changed and controlled in accordance with the high and low levels of the output of the flip-flop. The ignition timing according to this changed reference characteristic is further controlled in accordance with the output voltage of the retard control voltage generator (3).

By the way, in ignition timing switching control such as 1 or more, 1
Premium gasoline is used when the standard ignition timing is set to the delayed characteristic for regular gasoline.
When switching the reference ignition timing to the advance side compatible with premium gasoline, that is, when changing the 7-lip-flop decoy from the set state to the reset state, the output of this flip-flop decoy instantly causes the phase shifter (8) to shift. When the phase amount is reduced, the ignition timing instantly switches from the delayed ignition timing for regular gasoline to the advanced ignition timing for premium gasoline, rapidly entering the knock range and causing excessive engine damage that can even damage the engine. There is a risk of knocking. Therefore, in the present invention, the output of the flip-flop (Fig. 6(m))
into the pulse generator (4).
generates a pulse signal shown in Fig. 6(n) when switching characteristics from the lagging side to the leading side, and this pulse signal (Fig. 6(n)
)) as an input signal to the retard control voltage generator (3), the retard control voltage generating circuit (3) is forced to generate a retard control voltage at a predetermined level in the same way as a knock signal. (center part in figure (d)), by increasing the amount of retardation in the phase shifter (8), the ignition timing is rapidly advanced by a large amount when switching from the retard side to the advance side of the standard ignition timing characteristic. It prevents fluctuations and changes gradually to prevent excessive knocking in the engine. Since this retard control voltage generator (3) has a characteristic that the output level attenuates with a predetermined time constant for normal knock control, it is possible to use this characteristic to gradually change the ignition timing to the advance side. It can be easily configured without requiring any special circuit configuration.

〔Effect of the invention〕

As explained above, according to the present invention, by detecting knock occurring in the engine and controlling the standard ignition timing to be delayed or advanced depending on the occurrence situation, it is compatible with regular gasoline or premium gasoline. In an ignition system that is set to the ignition timing characteristics of This prevents the ignition timing from suddenly entering the knock range when changing the characteristics of the ignition timing, which not only allows setting an appropriate standard ignition timing for the engine corresponding to the gasoline used, but also prevents excessive knocking in the engine when changing the standard ignition timing characteristics. Furthermore, since the retard control signal generation circuit for knock control is shared to prevent sudden fluctuations in ignition timing at the time of switching, no special configuration is required for this purpose. This provides an excellent effect of being simple to configure.

[Brief explanation of the drawing]

1, 2, 8, 7, and 8 are characteristic diagrams of the engine. 1. Figure 4 is a block circuit diagram of an embodiment of the present invention.
FIGS. 5 and 6 show operation waveform diagrams of the respective parts of the fourth embodiment, respectively. In the figure, (1) is a knock sensor, (2) is a knock discrimination unit,
(3) is a retard control voltage generator, (4) is a reference ignition timing switching determination section, (5) is a pressure sensor, (6) is an adder, (7
) is the reference ignition timing signal generator, (8) is the phase shifter, (9)
represents a switch circuit, and Qd represents an ignition coil. Figures 1-2, 3, 7, 8 Procedural amendments (voluntary) Commissioner of the Japan Patent Office 1. Indication of the case Japanese Patent Application No. 1987-79548 2. Name of the invention Ignition timing control device for internal combustion engines 3. Relationship with the case of the person making the amendment Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name
(601) Mitsubishi Electric Co., Ltd. Representative Hitoshi Katayama 4, Agent 5, Detailed explanation of the invention column 6 of the specification to be amended Contents of the amendment (The specification is amended 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. Ignition timing switching determination means for determining switching of ignition timing characteristics; retard control signal generation means for generating a retard control signal based on the output of the knock signal determination means; and the ignition timing switch determination means and retard control signal generation. In response to the output of the ignition timing switching determining means, two preset standard ignition timing characteristics, advance side and retard side, are switched according to the output of the ignition timing switching determination means, and ignition is performed according to the standard ignition timing characteristic selected by this switching. ignition timing control means for controlling timing in accordance with the retard control signal; and retard control signal generating means when switching the reference ignition timing characteristic from the retarded side to the advanced side in accordance with the output of the ignition timing switching means. An ignition timing control device for an internal combustion engine, comprising means for generating a retard control signal for gradually changing the actual ignition timing by applying a predetermined input signal to the ignition timing control device.