JPS608345B2 - Ignition system for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device for an internal combustion engine, and particularly to an ignition device Z that controls ignition timing using an electronic circuit.

As is well known, the genius of combustion within the cylinder of an internal combustion engine. In order to extract the most efficient engine power from engine output, it is desirable to have the maximum pressure in the cylinder a little after top dead center (TDC)2. It is set to ignite at the appropriate time.

This optimal ignition timing mainly depends on the engine rotation speed and changes depending on the intake manifold pressure, so conventionally,
A governor advance device was used to set the advance angle for the former, and a mechanical control device such as a vacuum advance device was used to set the advance angle for the latter. However, in recent years, various types of internal combustion engines have been used. As electronic control has progressed, the ignition system described above has come to be controlled electronically instead of mechanically.There are already various configurations of this electronically controlled ignition system. The object of the present invention is to propose an electronically controlled ignition system for an internal combustion engine with a different configuration. An improved ignition system for an internal combustion engine is proposed in which the power consumed by the current flowing through the transistor is minimized.

4 In accordance with the above object, the present invention has a monostable multi-circuit that controls the switching timing of an ignition transistor from off to on, and furthermore, the time constant of the monostable multi-circuit is variable according to the rotational speed of the engine. Here, the time constant is controlled to be longer or shorter depending on whether the rotational speed is low or high, so that the slower the rotational speed, the faster the ignition transistor changes from off to on. The switching timing of the ignition transistor is delayed, and the switching timing is made faster as the rotational speed increases, so that the on-time of the ignition transistor in each ignition cycle is minimized regardless of changes in the engine rotational speed. The present invention is characterized in that the time period is fixed.The present invention will be explained below with reference to the drawings.

Fig. 2 is a block diagram showing an embodiment based on the present invention, and Fig. 2 is a time chart showing waveforms in the main part of Fig. 2.

In Fig. 1, the military Q turtle is a normal distributor system, and is equipped with a rotating gear 882 that rotates in conjunction with the crankshaft and a distributor Yugame 83 that is equipped with a side terminal that distributes the discharge voltage to each spark plug. It is shown disassembled.On the other hand, 84 is a normal ignition coil, with the primary winding connected to the battery (10 VB) and the distributor rotor R in the distributor turtle QI. The primary winding is connected to an ignition transistor 18 which is turned off by an ignition control pulse applied to the base of the ignition transistor 18. Particularly, the current passing through the primary winding is suddenly cut off. At this time, a high voltage is induced in the secondary winding, and the above-mentioned discharge voltage is obtained. When supplying the above-mentioned discharge voltage to the engine, the important issue is how to supply it, and the suitability of this timing determines the efficiency of the engine output as described above.For example, when one arbitrary To illustrate the movement of the piston inside the cylinder, the third
As shown in the figure, if TDC is the top dead center and BDC is the bottom dead center, the ignition control pulse to be applied to the ignition transistor 851 must be supplied an angle 8 earlier than TDC. This angle is well known as the advance angle. However, the size of this advance angle 8 must be determined by various factors, such as the intake manifold negative pressure mentioned above, engine rotation speed, vehicle speed, shift position, and engine cooling water temperature. Returning to FIG. 1 again to describe the configuration of the present invention, the distributor system 101
The rotating pickup 10 is located close to the rotating gear 102.
6 is added, and this rotary pickup 106 is electromagnetically coupled to the rotary gear 102.

Each time the rotating gear 102 approaches the rotating pickup 106, a pickup pulse corresponding to TDC in FIG.
The waveform is shaped through the process to obtain a pickup pulse P. The waveform of the pickup pulse P is as shown in FIG. However, in Figure 2 1 to 7, the vertical axis represents the signal amplitude,
It is shown with the elapsed time t taken as the axis. Further, in FIGS. 1 to 7, a region Lv indicates a case where the engine rotation speed is low, and a region field V indicates a case where the engine rotation is high speed.
Returning to FIG. 1, the pickup pulse P, sent out from the waveform shaping circuit 107 is
Reset input (R) of analog converter (D/A) 108
and a phase-lock relief on the other. It is applied to the circuit (PLL) 109. This phase-locked loop circuit 109 corresponds to the second pickup in addition to the conventional electronic advance angle distribution described above, and is a part that generates a signal indicating the rotation angle of the rotary gear 102. This is a part that generates a high-resolution rotational angle signal regardless of the rotational speed of the engine. 110 in the phase lock loop circuit 109 is a phase comparator (PD), and the waveform shaping circuit 1 as shown in FIG.
The pickup pulse train P from 07 is received at one input, and the oscillation output P2 from the voltage controlled oscillator (VNOF) 111 is applied to the frequency divider (DIV) 112 to generate a signal ( harm) is received first by the other, and the phase difference between them is detected. However, since the output from the phase comparator 118 is a signal with a pulse proportion proportional to the phase difference, it is sent to the integrator 1.
13 to convert it into a DC signal. The output Voc from this integrator 113 is a speed signal consisting of a DC voltage at a level proportional to the frequency of the pickup pulse P, and a part of it is applied to the control input of the voltage controlled oscillator 111 to adjust its oscillation frequency. change. Here, the voltage controlled oscillator 111 oscillates at a frequency N times the frequency of the pickup pulse P, and its oscillation output P2 is as shown at 2 in FIG. However, since the sound frequency is divided by the column 112' of this oscillator, at the time it is input to the phase comparator 1101, it has approximately the same frequency as the pickup pulse P, and the output from this frequency divider 112 is approximately the same frequency as the pickup pulse P. The frequency and phase of the pickup pulse P are controlled so that they always match the frequency and phase of the pickup pulse P.N mentioned here is a natural number, and in the example, N=128.The above-mentioned voltage controlled oscillator 111 Oscillation output P2 from
The frequency of the pickup pulses P, is always N times the frequency of the pick-up pulses P, and one pulse P, . and the next pulse P, 2 must be N.
pulses P2oo,,P2oo2,...P2,26(
N=128), and the same number is included regardless of the engine speed.

Therefore, this oscillation output P2 is "so-called rotating gear 102".
The desired high resolution of the rotation angle can be obtained by selecting a large value of N. Therefore, N rotation angle pulse trains P2o are arranged at equal intervals. ,,P2 no 2・
....If each of the P2 legs (N=128) is given a certain weight and the weight is added up, and this weighting level is h, then 50o before top dead center of any one piston. (Second
For example, P. ．． The rotation angle of the triangular wave changes linearly from level 0 to level Nh (constant) from 50 degrees before the top dead center of the next piton (e.g., corresponds to P, 2 in Figure 2 1). I get a signal. In short, no matter how the rotational speed of the engine changes, or in other words, no matter what the slope of the triangular wave, a certain voltage V on every triangular wave is ``always one-to-one with respect to a certain rotation angle 8 corresponding to this. Correspondingly, if you know the voltage on the triangular wave, you can know the rotation angle at that time.In FIG. Analog converter (D no A)
108, whose output waveform flame is as shown in FIG. Now, suppose that the piston in one arbitrary cylinder passes the top dead center 50o and the waveform shaping circuit 10T outputs a pickup pulse P, (see Fig. 2, 1). The digital-to-analog converter 108 receives at its set input S the rotation angle pulse P2 from the voltage-controlled oscillator 111 to reset it. Each pulse P2 is weighted to the level h mentioned above and this is accumulated.Here, from level 0 to level Nh (constant)
A triangular wave rotation angle signal S, which linearly changes in a stepwise manner in a fixed step up to a certain point, is obtained. In this way, we have obtained a triangular wave rotation angle signal S, which always changes linearly from level 0 to level Nh (constant), regardless of the engine speed. Based on this rotation angle signal S, we can determine the progress to be found. corner 8
This section describes the procedure for setting Z.

As already mentioned, the advance angle aG is mainly determined by factors such as engine speed, intake manifold member pressure, and engine coolant temperature, and in the embodiment, the advance angle aG is determined by these three factors.
shall be set. First, the signal representing the engine rotational speed is the speed signal V from the integrator i13 in FIG. The intake manifold negative pressure is obtained as a negative pressure signal Vv from the vacuum sensor 114, and the engine coolant temperature is obtained from the water temperature sensor 115 as a water temperature signal Vt. However, as is well known, the speed signal V. The negative pressure signal Vv representing the intake manifold negative pressure of the aircraft is converted into a signal conforming to the negative pressure angle characteristics. It is converted into a signal that conforms to the negative pressure single advance angle characteristic.
There are certain unique characteristics regarding the temperature of the engine coolant and the advance angle, but these are linear functions and are not as good as 3 when using a function generator. The above-mentioned converted signals are further input to the arithmetic unit 118 and added. The water temperature signal V is also input to the calculator 118 and predetermined calculations are performed. In this way, the lead angle setting signal T output from the calculator 118 is a signal that comprehensively takes into account three various factors for setting the lead angle 8. This advance angle setting signal T is applied to the second input of the comparator 119 and is compared with the triangular wave rotation angle signal S applied to the first input thereof. However, a predetermined DC bias is applied to the advance angle setting signal T so that it can be correctly compared at four levels with the triangular wave rotation angle signal S. This advance angle setting signal T is as shown by the dotted line in FIG.
The comparator 119, which compares the levels of the advance angle setting signal T and the rotation angle signal S, fluctuates like T''.
, >T, a rectangular wave P3 is output as shown in FIG. 24. The rising portion of this rectangular wave P3 (indicated by arrow U in FIG. 2) determines the advance angle 8 at which ignition is to be performed. Flip-flop circuit (F/F) 120
Assuming that the Q output of is at “H” level, this “
During the period of "H" level, the ignition transistor 105 is on, and a predetermined primary current is passed through the primary winding of the ignition coil 104. After this, the comparator Yugame 1
When the rectangular wave P3 is sent out from the output of 9, its rising portion U is applied to the reset input R of the flip-flop circuit 120, inverting its Q output from the "H" level to the "L" level. Due to this "L" level, the ignition transistor 105 is suddenly turned off. In this way, transistor 10
5 is turned on or off by the output of the flip-flop circuit 120, and its switching timing is determined by the rising edge U of the rectangular wave P3 and the falling edge of the output S2 from the monostable multi-circuit 121, which will be described later, as shown in FIG. It is determined. When the flip-flop circuit 120 receives this rising portion U, the transistor 05 abruptly switches from on to off, abruptly cutting off the primary current flowing through the primary winding. As a result, a high voltage is generated in the secondary winding of the ignition coil 104, and a discharge voltage SP (second
6 in the figure) is supplied. It is clear from the above explanation that this discharge voltage SP is generated at the optimum advance angle to maximize engine output efficiency depending on the engine condition. T
'', it changes to SP' or SP''. Note that the timing at which the set signal should be input to the set input S of the flip-flop circuit 102, that is, when the transistor 105, which has been off for a day, is turned on again. The timing is the output S of the monostable multi-circuit (M.M) 121.
Determined by the falling edge of 2. That is, when the rectangular wave P3 is output by the comparator 119, in the rising portion U of the rectangular wave P3, the output S2 of the monostable multi-circuit 121 rises as shown in FIG. After maintaining the "H" level for the period T7, it falls, and at this fall, the flop-flop circuit 1
20 to turn on the ignition transistor 105. In this case, if the time constant is set too long, 1
The period T7 during which the transistor 105 should be turned on in the second ignition cycle becomes shorter. If this period T7 is short, the transistor 105 is connected to the ignition coil 10.
It is impossible to pass a primary current with a sufficiently high amplitude to the primary winding 4, and as a result, a sufficient discharge voltage SP is not supplied, causing misfire. Therefore, the period T7 during which the transistor 105 is to be turned on should be maintained at least until the aforementioned primary current having a sufficiently high amplitude is conducted. On the contrary, monostable multicircuit 12
If the time constant ↑ of 1 is set too short, the period T↑ during which it should be turned on will become long. If this period T7 is unnecessarily long, power will be wasted. Therefore, in the present invention, this period T↑ is made the minimum necessary length, and moreover, the minimum necessary length is maintained regardless of the engine rotation speed. That is, the time constant of the monostable multicircuit 121 is made variable so that the period T↑ during which the transistor 05 is turned off becomes longer or shorter depending on the low speed or high speed of the engine. To achieve this, for example, R of the RC time constant circuit of the monostable multicircuit 121 may be configured with an FET, and a signal representing the engine rotational speed may be applied to the gate G of this FET (Fig. 1). . In this embodiment, as shown in FIG.
DC voltage Vo, which is the speed signal from the integrator 113 in
c is used as a signal representing the rotational speed of the engine. Note that this phase-locked loop circuit 109 is realized by, for example, MC4044, MC4024, and MC4014 manufactured by Motorola. As explained above, according to the present invention, electronic advance control can be performed while keeping the ON time of the ignition transistor constant, and the power consumed by the current flowing through the ignition transistor can be suppressed to the necessary minimum. Moreover, the engine speed can always be kept to the necessary minimum regardless of fluctuations in engine speed.

Furthermore, there is no need to create a new control input to the monostable multicircuit 121 that performs control for this purpose, and the output from the integrator 113 in the existing phase-locked loop circuit 1209 can simply be used. There is also an advantage.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of an ignition system for an internal combustion engine based on the present invention, Fig. 2 is a time chart showing main waveforms in Fig. 10, and Fig. 3 is a diagram illustrating the advance angle. FIG. In the figure, 102 is a rotating gear, 103 is a distributor, 104 is an ignition coil, 105 is an ignition transistor, 106 is a rotating gear pickup, 108
109 is a digital-to-analog converter, 109 is a phase-locked loop circuit, 118 is an arithmetic unit, 119 is a comparator, 120 is a flip-flop circuit, 121 is a monostable multicircuit, and r is a distributor rotor. 1st
Figure/Figure 2 Figure 3

Claims (1)

[Claims] 1. A distributor rotor r that distributes discharge voltage SP to the spark plugs of the internal combustion engine, and a pick-up pulse P_ synchronized with the rotation of the distributor rotor r.
1, a phase comparator 110 which inputs the pickup pulse P_1 to a first input and a feedback signal for phase comparison with the pickup pulse P_1 to a second input, respectively; Vessel 1
an integrator 113 connected to the output of the integrator 113 to take out a DC voltage V_D_C proportional to the pulse frequency of the pick-up pulse P_1; N (N is a predetermined natural number)
It consists of a voltage controlled oscillator 111 that generates a double oscillation output P_2, and a frequency divider 112 that is connected to the output of the voltage controlled oscillator 111 and divides the frequency of the oscillation output P_2 by 1/N to generate the feedback signal, The phase lock loop circuit 109 operates to zero the phase difference between the phase of the pickup pulse P_1 and the phase of the feedback signal, and is turned on and off via a control system connected to the phase lock loop circuit 109. an ignition transistor 105, a primary winding through which an energizing current that is controlled on and off by the ignition transistor 105 flows, and a secondary winding that induces the discharge voltage SP in accordance with the on and off control of the energizing current. an ignition coil 104 with a digital/analog control system, the control system takes the pickup pulse P_1 as a reset input and converts the oscillation output P_2 from the voltage controlled oscillator 111 into an analog quantity that linearly increases. converter 108 and the linearly rising analog signal S_1 from the digital/analog converter 108
a comparator 119 having a first input for receiving an advance angle setting signal T and a second input for receiving an advance angle setting signal T to be compared in level with said analog signal S_1; an arithmetic unit 118 that performs a predetermined logical operation on a plurality of sense signals V_D_C, V_v, V_t sent from a plurality of sensors provided at predetermined locations to detect the state of the internal combustion engine; The rise of the reversal detection signal P_3 outputted from the comparator 119 when the level of the advance angle setting signal T and the level of the analog signal S_1 are reversed is set input, and after the rise of the reversal detection signal P_3, the time constant τ is set. A monostable multi-circuit 1 that generates an output signal S_2 for a predetermined time determined by
21 and the fall of the output signal S_2 from the monostable multi-circuit 121 are set inputs, and the comparator 1
In the ignition system for an internal combustion engine, the flip-flop circuit 120 generates an output to be applied to the base of the ignition transistor 105 by using the rising edge of the reversal detection signal P_3 outputted from the ignition transistor 105 as a reset input. The circuit 121 makes the time constant τ variable by using the DC voltage V_D_C from the integrator 113 in the phase lock loop circuit 109 as a control input,
An ignition device for an internal combustion engine, characterized in that the time constant τ is lengthened or shortened depending on whether the internal combustion engine rotates at a low speed or a high speed.