JPS6045310B2 - Non-contact ignition device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-contact ignition system, and more particularly to a non-contact ignition system that can delay ignition timing during aircraft starting.

The ignition timing of a typical internal combustion engine is approximately 100 minutes before top dead center (BT
OC approximately 100). Since the combustion speed of the air-fuel mixture is almost constant with respect to the rotational speed of the engine, combustion is completed almost simultaneously with ignition at extremely low speeds such as during startup. In other words, since combustion is completed approximately 100 degrees before top dead center, instead of the torque overcoming top dead center (■℃), the torque becomes a reverse torque that goes against the starting torque of the starch intermotor and reduces the rotation of the engine. In many cases, the engine may become stuck and become difficult to start. This tendency becomes more pronounced as the ignition timing advances. In addition, even if the starting torque of the starch intermotor is sufficiently large, if the ignition timing is advanced, the air-fuel mixture will not be sufficiently compressed, resulting in low combustion pressure resulting from ignition, which may not result in complete explosion, making it difficult to start. be. SUMMARY OF THE INVENTION In order to solve the above-mentioned drawbacks, the present invention provides a non-contact ignition device suitable for delaying the ignition timing at the time of aircraft start-up to ensure smooth start-up.

The present invention makes use of the fact that the battery voltage decreases when the engine starts, determines whether to start the engine by detecting this decrease in battery voltage, and switches the engine when the voltage of the battery power source falls below a predetermined level. When turned on, the AC ignition timing signal from the AC voltage generator is delayed by a predetermined angle by the action of a time constant circuit consisting of a capacitor and a resistor.

Hereinafter, one embodiment of the present invention will be described. In FIG. 1, PU is an AC electric machine that rotates in synchronization with the engine and generates an ignition timing signal, and R1 is a change in winding resistance of the AC generator PU due to temperature. The resistor R2 for correcting is a resistor J for applying a bias current to the transistor Q1 that amplifies the ignition timing signal of the AC power generator Yanagawa.

The capacitor Cl and the resistor R3 are used to compensate for the delay in the ignition timing signal current generated by the alternator PU.
is a diode that passes the negative current of the AC electric machine PU, R4 is a transistor, the collector resistance of Q1, and Q2 is a transistor;
A transistor R5 is a collector resistor of the transistor Q2, which amplifies the operation of the transistor Q1 by phase inversion. Q3 is a power transistor, which amplifies the operation of transistor Q2 by switching in the same phase, and when it is on, it conducts current to the ignition coil Co, and when it is off, it cuts off the current flowing through the ignition coil CO, and sends a high voltage to the secondary side. Generate voltage. P is a spark plug and B is a battery. R6 is a resistor for supplying base current to transistor Q4, and ZD is a Zener diode through which Zener current flows when the voltage of battery B is above a specified value and becomes non-conductive when it is below the specified value, and controls transistor Q4. do. R7 is the collector resistance of the transistor Q4, and C2 is a capacitor, which slows the turning on and off of the transistor Q4 due to the Miller integral effect. Q5 is a transistor that inverts the phase of the operation of transistor Q4, and when turned on, causes an alternating current generated by alternator PU to flow through capacitor C3 and resistor R8. Next, the operation will be explained with reference to Fig. 1 and Fig. 2 A, B, and C.
When is stopped as shown in Figure 2A, transistor Q1 is on as shown in Figure 2B, transistors Q2 and Q3 are turned off, and current flows through the ignition coil CO as shown in Figure 2C. Not flowing.

Next, the alternator PU rotates to generate an alternating current voltage as shown in Figure 2A, and when the negative voltage becomes below the cutoff level of the transistor Q1, the transistor Q1 turns off and the power transistor Q3 turns on, turning the ignition coil Second to CO
Turn on the power as shown in Figure C. When the AC voltage switches from negative to positive, transistor Q1 is turned on and transistor Q3 is turned off, cutting off the current flowing through the ignition coil CO and causing a second
Generate high voltage as shown in Figure C. The above operation occurs under normal operating conditions when the battery voltage is approximately 12 volts or higher, but when starting the aircraft, the starting motor
0 to several hundred a. The battery voltage drops to approximately 6-8 volts due to the ampere current flowing through it. Here, if the Zener voltage of Zener diode D is set to about 10 volts, the battery voltage will be less than 10 volts at the time of starting the aircraft, so the Zener diode is small! Zener current does not flow, transistor Q4 is turned off, transistor Q5 is turned on, and a positive alternating current generated by alternator PU flows through capacitor C3 and resistor R8, charging capacitor C3. When the voltage across capacitor C3 and resistor R8 increases to transistor QlOOVBE, transistor Q1 is turned on and power transistor Q3 is turned off, cutting off the current flowing through ignition coil CO and generating a high voltage. In this way, when the aircraft is started, a charging current flows due to the time constant of capacitor C3 and resistor R8, so
The timing at which the transistor Q1 turns on is delayed, and the ignition timing can be delayed. (Indicated by broken lines in each figure in Fig. 2.) In normal operating conditions, since the battery voltage is 10 volts or more, Zener current of Zener diode ZD flows, transistor Q4 is on, transistor Q5 is off, and capacitor C3 No charging current flows through the ignition, and the ignition timing is not delayed. The capacitor C2 slows down the on/off operation of the transistor Q5 so that the transistor Q1
This stabilizes the operation of the Figures 3A and 3B show the relationship between battery voltage and ignition timing. When the starting motor is operating, the battery voltage falls below the specified value as shown in Figure 3A, and the ignition timing changes. As shown in FIG. 2B, there is a θ angle delay.

Changing the delay amount θ angle or changing the θ angle with respect to the starting rotation speed can be done arbitrarily by changing the values of the capacitor C3 and the resistor R8. Figures 4, 5, and 6 show other embodiments of the present invention, all of which show parts that detect the specified value of battery voltage, and the same symbols as in Figure 1 are They work the same way.

Figure 4 utilizes the fact that the forward voltage of the diode D1 changes depending on the forward current, that is, the battery voltage.When the battery voltage is above a specified value, the diode D1
The forward voltage of the transistor Q4 is high, and the transistor Q4 is turned on.

FIG. 5 utilizes the voltage drop across the resistor RlO, and turns on the transistor Q4 when the battery voltage exceeds a specified value. Further, in FIG. 6, when the battery voltage is above a specified value, the base current of the transistor Q4 increases to turn on the transistor Q4. As described above, according to the present invention, the ignition timing can be delayed to a desired position when starting the engine, thereby reducing the generation of reverse torque due to the overadvanced position of the ignition timing, which is a drawback in the conventional technology. Since the combustion pressure can be increased at the same time, the engine can be started smoothly.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figures 2A and B
, C, D are explanatory diagrams of the operation of Fig. 1, Fig. 3 A, B are explanatory diagrams of the relationship between battery voltage and ignition timing, Fig. 4, Fig. 5,
FIG. 6 is a circuit diagram of a battery voltage specified value detection section showing another embodiment of the present invention. PU... AC generator, Q1-Q5... Transistor, D... Zener diode, CO...
...Ignition coil.

Claims (1)

[Claims] 1 An alternator that generates an ignition timing signal in synchronization with engine rotation, and an ignition coil that generates an ignition timing signal in accordance with the output of the alternator.
A non-contact ignition device comprising an ignition circuit that turns on and off a current, and is operated by battery power, includes means for detecting the battery voltage and generating an output when the battery voltage falls below a predetermined level. A non-contact ignition device, characterized in that it is provided with ignition timing delay means that is activated when an output is generated from the means to delay generation of the ignition timing signal.