JPS628382Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor ignition device, and particularly provides an ignition device that facilitates starting when the engine rotates at low speed. FIGS. 1, 2, and 3 are circuit diagrams showing conventional devices of this type, a waveform diagram of the shear breakage current, and a diagram showing the relationship between the engine speed and the shear breakage current.

In Fig. 1, 1 is an ignition coil, which consists of a primary coil 2 and a secondary coil 3 wound around the same iron core.
A voltage is induced in the primary coil 2 by a magnet rotating synchronously with an engine (not shown). This induced voltage supplies a base current to the main transistor 6 of the transistor switching circuit 5 via the resistor 7. As a result, the transistor switching circuit 5 is turned on, and a current IC flows through the parallel circuit of the primary coil 2 and the transistor switching circuit 5. Due to the rise in the ce terminal voltage of the transistor switching circuit 5, the voltages of the voltage dividing resistors 9 and 11 increase, increasing the base current of the transistor 8 of the control current bypass transistor circuit A, and turning on the transistor 8. do. As a result, the control current of the control current supply circuit (portion b in the figure) of the transistor switching circuit 5 is turned off, and the current IC of the switching circuit 5 is abruptly cut off. The sudden interruption or disconnection induces a voltage in the ignition coil 1, which causes the secondary coil 3 to generate a boosted high voltage, causing a spark to ignite the engine in the plug 4. Note that 10 is a temperature compensation diode. Figure 2 shows the transistor switching circuit 5.
(In the explanation, the current when the current is cut off is called the cut-off current.) Third
The figure shows the relationship between the engine speed and the disconnection current of the transistor switching circuit.

In the conventional device as described above, as shown in Figure 3, when the engine reaches a certain rotational speed N1, there is no need for spark generation or a current cutoff occurs, and after that, regardless of the increase in the rotational speed, the current cutoff occurs. becomes constant. In this way, in conventional devices, the shearing current has a constant relationship with changes in rotational speed, so if the spark starting rotational speed N1 is lowered to make it easier to start the engine at low speed, the shearing current will decrease. However, it has been difficult to secure sufficient spark generation energy in the normal rotation range of the engine. In order to solve the above-mentioned drawbacks, the present invention has developed a transistor ignition system that cuts off the current with a small shedding current during low-speed rotation such as when starting the engine, and achieves a constant high shearing current in the normal rotation range. It is related to the device.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 4, FIG. 5, and FIG. 6 are a circuit diagram, a waveform diagram of the shear breakage current, and a relationship diagram between the engine speed and the shear breakage current, showing an embodiment of the present invention. Figure 4 is the first
The same reference numerals as in the conventional device in the figure indicate the same parts. In particular, the second control current bypass transistor circuit B is additionally connected to the first control current bypass transistor circuit A in FIG. Forms a parallel connection relationship. If configured as shown in Fig. 4, the transistor switching circuit 5 is turned on by the voltage induced in the primary coil 2 of the ignition coil 1 when the engine rotates at low speed, and when the current IC flows, the circuit 5
A terminal voltage between ce and e is applied to the circuit B, which charges the capacitor 15 through the resistor 14. At a constant charging voltage, the bypass transistor 13 is turned on, and the control current supply circuit of the circuit 5 ( The control current (portion b in the figure) is bypassed, and the circuit 5 is turned off. Therefore, by cutting off the current IC flowing through the circuit 5, the rotational speed N is reduced as shown in Fig. 5.
2, N3 or N4 corresponding to the respective rotational speeds can be obtained, the spark generation energy necessary for ignition is stored in the ignition coil 1, and the ignition spark is generated in the plug 4. occurs. The relationship between each rotation speed in Fig. 5 is N2<N3<
N4 is the normal rotation area. Furthermore,
When the rotation speed is increased to N4 or more, the voltage dividing resistors 9 and 1 of the first control current bypass transistor circuit A are
The voltage of 1 increases in accordance with the rise in the voltage between terminals ce and ce, rapidly turning on circuit A, and as shown in Fig. 5.
It generates an ignition spark in the normal rotation range by generating a squeak or a current cut-off similar to that of IC4. When connecting the capacitor 15 to the base supply circuit of the second control current bypass transistor circuit B, it may be connected between the base and emitter of the bypass transistor 13 as shown in FIG. 4, but as shown in FIG. It is equivalent to connect a capacitor 15 between the collector base and the collector base, and the same effect is obtained. Further, the transistor switching circuit 5 in the embodiment shown in FIG. 4 is similar to that shown in FIGS.
A composite connection type transistor may be used as shown in the figure. Also, in the above description of the present invention, one of the ignition coils is
Although the secondary coil also serves as a generating coil, the same effect can be obtained even if the generating coil 1' and the ignition coil 1 are separated as shown in Fig. 10, and this is not within the scope of the claims of the present invention. be. Furthermore, in the embodiment, the control current bypass transistor circuit is A.
and B were used, but in order to obtain the effect of the present invention, a transistor circuit for control current bypass can be added as necessary, and the capacitor 15 for the delay circuit can also be added to the transistor circuit for control current bypass. In addition to being connected to one circuit, it may be additionally connected to other bypass transistor circuits. As mentioned above, the present invention uses a delay circuit that adds a capacitor connected to the base current supply circuit of the second control current bypass transistor circuit even when the voltage induced by the magnet during low speed rotation is in a low voltage range. The ignition coil obtains the energy needed to generate the spark required for ignition, making the spark generation energy almost constant in the normal rotation range, making it easier to start the engine, especially at low speeds, and is a practical solution. The effect is huge.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are circuit diagrams of the conventional device, a waveform diagram of the shear breakage current, and a diagram of the relationship between the engine speed and the shear breakage current, and Figures 4, 5, and 6 are the circuit diagrams of the conventional device. A circuit diagram of one embodiment, a diagram of the shear cut-off current waveform and a diagram of the relationship between the engine rotation speed and the shear cut-off current, FIGS. 7 and 8 are connection diagrams of the composite connection type transistor, and FIG. 9 is a diagram of the connection of the capacitor 15 and other FIG. 10 shows another embodiment of the present invention in which the generating coil and the ignition coil are separated. In the figure, 1 is an ignition coil, 1' is a generator coil, 2 and 3 are its primary and secondary coils, 4 is a plug, 5 is a transistor switching circuit, A is a first control current bypass transistor circuit, B is a second control current bypass transistor circuit, 6, 8,
13, 18, 19, 22 and 23 are transistors, 7, 9, 11, 14, 17, 20, 24 and 25 are resistors, 15 is a capacitor, c, b and e are external connection terminals of 5, IC, IC1, IC2, IC3 and
IC4 arm break current, N1, N2, N3 and N4
is the engine rotation speed and t is the time.

Claims (1)

[Claims for Utility Model Registration] (1) A transistor ignition device in which a transistor switching circuit is connected in parallel to the primary side of an engine ignition coil and generates a spark voltage by turning on and off the switching circuit. Two or more control current bypass transistor circuits are connected to the control current supply circuit, and a delay circuit consisting of a resistor and a capacitor is connected to the base current supply circuit of at least one control current bypass transistor circuit to facilitate low-speed startup. A transistor ignition device characterized in that it is adapted to be run-in. (2) Utility model registration claim 1, characterized in that a capacitor is connected via a resistor between the base and emitter of the bypass transistor included in the base current supply circuit of at least one control current bypass transistor circuit. Transistor ignition device as described in section. (3) Utility model registration claim No. 1, characterized in that a capacitor is connected via a resistor between the collector base of the bypass transistor included in the base current supply circuit of at least one control current bypass transistor circuit. The transistor ignition device according to item 1. (4) The transistor ignition device according to claim 1, which is characterized in that a composite connection type transistor is used in the transistor switching circuit.