JPS59215963A - Ignition device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To make improvements in the accelerativeness of an engine as well as in a rate of fuel consumption, by determining an ignition timing with a wave- form spark advancing angle controlled by a relatively broad angle signal in case of a low engine speed range, while determining the ignition timing with operation results on the basis of suction pressure in case of a medium-high engine speed range. CONSTITUTION:In this ignition device, there are provided with a generator coil 1 generating AC voltage in synchronous with engine revolution, a signal coil 8 generating a first angle signal being narrow in an angle range corresponding to the specified crank position of an engine, and a signal coil 10 generating a second angle signal being relatively broad in the angle range as delayed from the first angle signal. In addition, an operation circuit 14, which receives the first angle signal and calculates a delay position rather than the first angle signal generation position in response to a signal out of a suction pressure signal generating device 16, is installed as well. Moreover, there is provided with an adjusting device 13, which receives an output signal of the operation circuit 14 and adjusts the second angle signal for the duration of the said output signal, whereby an operating point of time in an on-off operation device 7 is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine ignition system, and particularly to a non-contact type ignition system suitable for magneto ignition.

In general, for internal combustion engines such as two-wheeled vehicles and four-wheeled vehicles, ignition is performed according to the engine speed in order to prevent kicking at low speeds, improve startability, etc., and to improve horsepower at medium to high speeds. It is equipped with a rotation advance function to control the timing. Furthermore, in order to improve acceleration performance, fuel efficiency, etc., a negative pressure advance function that controls the ignition timing using the engine's intake negative pressure is generally used in conjunction with the engine. Conventionally, as the ignition timing control means using this negative pressure advance, a method has been used in which the ignition timing is mechanically controlled by a dial 7 ram that responds to the intake pressure of the engine. However, due to reasons such as durability and accuracy, in recent years, devices that detect the intake pressure of the engine using a semiconductor pressure sensor and control the ignition timing based on the sensor output have become popular.

In view of the above-mentioned circumstances, the present invention has been developed to provide an ignition signal waveform with a relatively wide angle width that accompanies the rotation in a low-speed rotation region such as a 2-cycle engine that does not require relatively high ignition timing accuracy for the purpose of preventing kickbacks and improving startability. This is supported by a waveform advance method that takes advantage of the growth in engine speed, and a negative pressure advance function is required to improve acceleration performance and fuel efficiency, and from medium to high speeds where ignition timing accuracy is required. In this area, the present invention provides an ignition system with a negative pressure differential angle that is configured to be able to handle the ignition timing by calculating the ignition timing according to the intake pressure of the engine, thereby eliminating the need for a mechanical control section. be.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
In the figure, (1) is a power generating coil of a magneto (not shown) which is a power source device and generates positive and negative alternating current voltages in synchronization with the rotation of the engine. [2), f3) is this generator coil (1
), (4) is a capacitor that is charged by the output of the generator coil (1) rectified by this diode (2), and (5) is connected to the discharge circuit of this capacitor (4). a primary coil (5a) which is an ignition coil connected in series with the capacitor (4);
It consists of a secondary coil (5b) connected to a spark plug (6). (7) is a thyristor which is a switching element provided in the discharge circuit of the capacitor (4), and when the thyristor (7) is conductive, the charge of the capacitor (4) is discharged. (8), Q[) are signal coils that generate signals synchronized with the engine.
) generates a first angle signal having a narrow angular width corresponding to a predetermined crank position of the engine, and the signal coil 00 generates a relatively narrow first angle signal corresponding to a crank position related to a predetermined angle from the generation position of the first angle signal. A second angular signal having a wide angular width is generated. (91,01) is a reverse current blocking diode, 0'2 is a current control resistor for directly supplying the second angle signal to the gate of thyristor (7), and α3 is a current control resistor for directly supplying the second angle signal to the gate of thyristor (7). (7) A transistor serving as an adjusting means for controlling the timing of supply to the gate, and is connected so as to bypass the second angle signal to ground. α→ is
This is an arithmetic circuit that receives the first angle signal and calculates a delayed position from the generation position of the first angle change signal according to the intake pressure of the engine.
It is connected to the base of 3. αQba.

As shown in FIG. 3, the pressure signal generating means generates a pressure signal voltage (r) proportional to the intake pressure of the engine, for example, a semiconductor pressure sensor is used, and controls the arithmetic circuit α.

Next, FIG. 2 is a detailed circuit diagram of the arithmetic circuit 04, in which (141) is an R-S flip-frog that is set in response to the first angle signal, and (144) is an operational amplifier. Its inverting input terminal is connected to the output terminal (Q, ) of the R-8 flip-flop (141) through a resistor ('142).
and to its own output terminal via a capacitor (145), the non-inverting input terminal of which is biased to a pressure signal voltage (ffr) proportional to the intake pressure of the engine. (145) is a voltage comparator,
Its inverting input terminal is connected to the output terminal of the operational amplifier (144), its non-inverting input terminal is grounded, and its output terminal is the R-8 flip-flop 1'141).
It is input to the reset terminal (R) of.

Next, in FIG. 4, (b) to (f) are the same as the above-mentioned FIG. 1.

3 shows a time chart of voltages A-K at various parts in FIG. 2. FIG. Figure (a) is a time chart showing each sign of the crank position of the engine, and point (M) is the maximum advance position i! required by the engine! This is the first angle signal generation position. Point (S) indicates the second angle signal generation position.

Next, the operation of the above embodiment will be explained.

First, in the CD type magneto ignition device shown in Fig. 1, the rectified output of the generator coil (1) is used to convert the capacitor (
4) is charged to the illustrated polarity, and the completed charge is applied to the primary coil (5a) of the ignition coil (5) by making the thyristor (7) conductive at the ignition timing of the engine. As a result, a high voltage is generated in the secondary coil (5b), causing a spark to fly to the spark plug (6).

Next, a method for controlling the conduction timing of the thyristor (7), that is, the ignition timing, will be explained with reference to Figs. 2, 3, and 4, and Fig. 5 showing the ignition timing characteristic diagram. If the engine is in a rotation range higher than the rotation speed N shown in FIG. 5 and the intake pressure of the engine is 760 mrnHg (atmospheric pressure), the operation will be as described below.

As shown in FIG. 3, the pressure signal generating means αe generates a pressure signal voltage vr proportional to the intake pressure of the engine, and when the intake pressure of the engine is 760 mmHg, this voltage becomes Vrl. This pressure signal voltage Vrl is supplied to the non-inverting input terminal of the operational amplifier (144) and becomes the non-inverting input terminal voltage.

On the other hand, the R-S flip-flop (141) is set by the first angle signal A generated at the engine crank position (station), and its output voltage B becomes high level as shown in FIG. 4(d). When the output voltage B reaches a high level, the capacitor (143) that has been charged to the voltage polarity shown in FIG. 2 starts discharging at a current 12 shown in the equation below.

v, Vrl 12-□ However, vH is the level voltage of the flip-flop (141), and R is the resistance of the resistor (142).

Next, as the capacitor (n-3) starts discharging, the output voltage E of the operational amplifier (1aJ) drops as shown in FIG. When the voltage comparator (145) reaches the output of the voltage comparator (145),
A positive pulse voltage is generated. This positive pulse 1d pressure is
This becomes a reset signal for the R-S flip-flop C141), and the output voltage B of the R-S flip-flop t'141) becomes low level. R-S flip-flop (
14x) becomes a low level, the capacitor (143) begins to charge to the voltage polarity shown in FIG. The charging current 11 at this time is Vrl 11=□ Now, the angular width θl at which the Q output of the R-8 flip-flop (141) is at a high level is a triangular wave in which the charges charged at 11 are discharged at 12; Charge/discharge cycle 36
When it is assumed to be 0°, 1l(360-θI)='i2·θ1, and if iI+'2 is substituted into this and solved, Vrl θl = -X 360°vH. In the general formula, if the angular width is θ, then ■r θ=−8360°vH. In this way, the angle θ or θ1 has a value that does not depend on the rotational speed of the engine and only depends on the intake pressure vr, since vll can be maintained at a constant value.

The Q output of this 7 lip-flop (141) is the resistance (I
5) to the base of the transistor 09, and while this Q output is at a high level, the transistor 09 is turned on and acts to bypass the angle signal C and short-circuit it to ground. Therefore, as we are currently considering, when the engine speed is higher than N] and the intake pressure is 760 mm Hg, each waveform in the center of the time direction in Fig. 4 corresponds to this, and the thyristor (7) The waveform D in Fig. 4(f) is applied to the gate of
2 is applied. That is, the ignition timing in this case is delayed by the calculated angle θ1 from the generation position of the first angle signal A, and is constant with respect to rotation, as shown in the characteristic Q1) shown in Figure $5 of the ignition timing characteristic diagram. Becomes a characteristic.

Next, when the engine intake pressure is lowered by 5 (negative pressure) in the engine rotation range higher than the rotation speed N1 shown in FIG. 5, the pressure signal voltage vr becomes < Vrz
It can be understood that the calculated angle change θ is reduced to a value corresponding to Vr2. Thereafter, the operation is similar to that described above, and the ignition timing is controlled according to the intake pressure of the engine.

Next, when the intake pressure of the engine becomes even lower, that is, the calculated angle θ becomes even smaller and reaches the calculated angle θ2 shown in the B waveform of FIG. 4(d),
As can be understood from the D3 waveform shown in f), even if the second angle change signal 0 is bypassed by the transistor αj for the calculation angle θ2 period, the second angle signal is still not present when the bypass is completed. Since the conduction voltage of the thyristor (7) has not reached ■G, the calculation result of the calculation circuit 04) no longer contributes to the ignition timing.

That is, the ignition timing occurs when the angle signal C of @2 reaches the conduction voltage vG of the thyristor (7), and the characteristics shown in Fig. 5 (
As shown in b), an upper limit is determined for the engine's intake pressure.

This operation is the same in the region where the engine rotational speed is equal to or less than Nl. However, at low speeds below N1,
Since the direct pressure value of the second angle signal 0 is small because the rotation speed is low, even if the above calculated angle θ, at which the intake pressure of the engine corresponds to atmospheric pressure, becomes θ1 and the second angle signal C is bypassed during that period, When the bypass is completed, the second angle signal has not yet reached the conduction voltage V of the thyristor (7). The reason why the time at which the second angle signal C reaches the conduction voltage VG of the thyristor (7) advances as the rotational speed increases is due to the waveform advance of the conventionally known contactless magneto ignition device. It is. That is, the ignition signal output, which has a relatively wide angular width, grows as the rotational speed increases, and it is clear that this growth is even greater at low speeds.

By the operation as described above, the ignition timing characteristics of the engine are as shown by the solid line in FIG. 5. That is,
In the rotation range where the engine rotation speed is N or less, the rotation angle advances with the growth of the second angle signal C having a relatively wide angle width, and in the rotation range where the engine rotation speed is N1 or more, 1
The characteristic Qυ is that ignition occurs at a position delayed by the calculated angle θ calculated according to the engine intake pressure from the angle signal generation position (B), and the upper limit ignition position for the engine intake pressure in this rotation range. is determined by the second angle signal.

As described above, according to the present invention, in the engine rotation range from medium speed to high speed, the ignition timing is determined based on the calculation result calculated according to the intake pressure of the engine in response to the first angle signal. As a result, it is possible to accurately improve engine acceleration, fuel efficiency, and stable horsepower performance in the normal engine speed range from medium to high speeds, and to prevent excessive engine intake pressure that would impair engine performance. For the corner,
Since the upper limit of ignition timing can be suppressed by the second angle signal, there is no need for a circuit mechanism to limit the pressure signal in the pressure signal generating means, and only a rotation advance is required to prevent kicking and improve startability. In the low-speed rotation range, relatively high ignition timing accuracy is not required, and the ignition timing can be determined by advancing the waveform by the second angle signal, which has a relatively wide angle width. Therefore, a simple circuit F! kWIt
It is possible to provide suitable ignition timing control for the engine according to the actual situation, such as obtaining a rotational advance at .

[Brief explanation of the drawing]

^ Figure 1 is an electric circuit diagram showing one embodiment of the present invention, Figure 2 is an electric circuit diagram of the main part of the embodiment of Figure 1, Figure 3 is an output characteristic diagram of the pressure signal generating means, and Figure 4. 5 is an operation waveform diagram explaining the operation of the embodiment, and FIG. 5 is an ignition timing characteristic diagram according to the embodiment. In the figure, (1) is the power generation coil, (5) is the ignition coil, and (6) is the ignition coil.
) is the spark plug, (7) is the opening/closing means, (8), αO is the signal means, α is the adjustment means, α→ is the calculation means, and Qf19 is the pressure signal generation means. or a corresponding portion. Agent Masuo Oiwa No. 1 I￥I Fig. 6 W, child rotational speed I Fig. 2 (b) (0) (d-) Fig. 3 Fig. 4

Claims (1)

[Claims] A signal means for generating a first angle change signal in synchronization with the engine rotation, and a signal means for generating a second angle signal having a relatively wide angle width and delayed from the first angle signal in synchronization with the engine rotation. , an opening/closing means that operates when the angle signal @2 reaches a predetermined value and changes the current flowing to the ignition coil to generate an ignition voltage; a means that generates a pressure signal according to the intake pressure of the engine; Receiving the first angle change signal and the pressure signal, the calculating means generates a pressure time width signal having a time width corresponding to the pressure signal from the time point at which the first angle signal is generated, and a calculation means that receives the pressure time width signal. An internal combustion engine ignition device comprising adjusting means for adjusting the second angle signal during the duration of the pressure duration signal and adjusting the operating point of the opening/closing means.