JPS6056392B2 - igniter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device that uses a single inverter circuit to improve the ignition performance of petroleum, etc., and particularly relates to an ignition device that compensates for input voltage fluctuations and compensates for temperature. It is.

By discharging using a single-stone inverter circuit,
When igniting petroleum, etc., this ignition device uses a thyristor, sidac, discharge tube, or shock radar auto as a switching element, so it cannot flow a large current, and the discharge is intermittent (6 to 8 times/second), and the ignition energy is small.

For this reason, there is a drawback that even if oil is sprayed at a low temperature (for example, -20° C.) and an attempt is made to ignite it, it cannot be ignited. Therefore, an ignition system using a leakage transformer TL as shown in Fig. 1 has been considered, but the volume and weight of the ignition device will be large, and it will not only be expensive but also require compensation for input voltage fluctuations and temperature changes. I can't do it. This invention configures a series resonant circuit on the primary side of the transformer, sets this resonant circuit to maximum resonance under a predetermined state of the ignition load, and achieves easy and reliable ignition. The voltage dividing point of a voltage dividing circuit consisting of capacitors connected in parallel to the line is connected to the base of the transistor, and the temperature characteristics of the capacitors in this voltage dividing circuit are varied so that as the temperature rises, the voltage at the voltage dividing point decreases. It is an object of this invention to provide an ignition device that can compensate for voltage fluctuations at the input of a transistor and prevent thermal breakdown due to temperature rise. Hereinafter, the present invention will be specifically explained based on illustrated embodiments.

In FIG. 2, symbol T is a transformer, whose primary side is of the collector grounded type. A voltage dividing circuit A consisting of capacitors C3 and C4 connected in series is connected in parallel to the base winding NB of the transformer T, and its voltage dividing point a is connected to the base of the transistor Q via a resistor R2. Further, one end of the one capacitor C4 is connected to the emitter of the transistor Q, so that the voltage across the capacitor C4 is applied between the base and emitter of the transistor Q. An emitter winding NE is further connected to the emitter of the transistor Q, and a resonance capacitor C5 is connected to the emitter winding NE. Further, a spark plug is connected to the secondary winding N2 of the transformer T, forming a gap in the discharge circuit. Hereinafter, the resonant circuit in the above inverter circuit will be explained first, and then the function of the voltage dividing circuit A will be explained. First, in the above inverter circuit, the emitter winding N of the output transformer T.

When a voltage is induced in the capacitor C5, a series resonant circuit including the resonant capacitor C5 is formed. By setting the inductance of , resonance operation is possible at any frequency. Now, when the AC input voltage is gradually increased from a low voltage, the voltage from the transistor Q to the emitter winding N. The current flowing to the winding NE also increases, and L in the impedance (VRdc2 + storage) of the winding NE decreases,
The oscillation frequency increases as the AC input voltage increases. For example, if the capacitance of the capacitor C5 and the inductance of the winding NE are set so that it resonates at a set frequency (for example, 20 KHz) with an AC input of 100 V, then a resonance state occurs and the above-mentioned resonant circuit is connected to the winding NE. ．． There is only a direct current resistance Rdc, and the maximum current flows. This large current generates a power equal to the supply voltage x ωL/RdO in the emitter winding NE, as per the theory of a series resonant circuit. This is further boosted by the secondary winding N2 to perform high voltage ignition.
In this way, the induced voltage on the primary side (Emitsu! evening winding NO) is about twice that of a general one-wheel inverter, so the secondary winding N
If 2 is less, the high frequency loss is also reduced and the efficiency is improved. In the circuit system of this invention, the input voltage is 10
When resonance occurs at 0V, the input power drops at around 100V.

This is due to resonance slippage, and if the phase difference is large,
The input current no longer flows in the opposite direction. That is, in this circuit system, there is a kind of regulator circuit function, and this operates effectively. Therefore, in setting the resonant circuit constant,
Temperature characteristic compensation can also be achieved by maximizing resonance so that the ignition performance is maximized under a predetermined ignition load condition, for example, at a low temperature (-20° C.).

For this purpose, the temperature characteristics of the ferrite core (H3S) of the high voltage transformer T can be utilized in this circuit. In other words, the μ of H3S material at -20°C is 30 to 40 lower than that at room temperature.
This is a 1% decrease. The resonant capacitor C5 may be set so as to resonate with the inductance of the emitter winding NE when this p decreases. Actual data shows that the power was approximately 10% higher than when it was at room temperature. Next, the two functions of capacitors C3 and C4 of voltage dividing circuit A will be explained.

This type of circuit usually has a base winding N, as shown in Figure 4.
The voltage generated at 8 is the capacitor C connected in parallel. In this case, as the ambient temperature rises, the base-emitter voltage of transistor Q decreases, the base current increases, and transistor Q It becomes deeply saturated and the collector current increases. As a result, power loss in transistor Q increases, which eventually leads to thermal destruction of transistor Q. However, in the voltage divider circuit configuration of the present invention described above,
For example, use capacitors C3 and C4 with temperature characteristics as shown in Figure 3, that is, capacitor C3 has a capacitance that is almost constant S with respect to temperature, and capacitor C4 has a capacitance that increases with temperature. When using a capacitor with a temperature characteristic of
The voltage across both ends VC4 of 4 is expressed by the following equation. In other words, as is clear from the same equation, if voltage dividing capacitors C3 and C, which have different temperature characteristics are selected so that the voltage applied to one capacitor C, decreases, the voltage dividing point a will change as the ambient temperature rises. voltage decreases.

Therefore, even if, for example, the base-emitter voltage of transistor Q decreases due to temperature, the potential at voltage dividing point a also decreases in accordance with the decrease, so that the base current does not increase A constant base current S can be passed to the base of the transistor Q.

In addition, when selecting the capacitor mentioned above, the capacitor C
Of course, the capacitor C3 may have a negative temperature characteristic with S4 being approximately constant, or the capacitor C3 may have a more positive or negative temperature characteristic than C4.

The second function is assuming that the input voltage V1, that is, the voltage generated at the emitter winding fluctuates by 10V, and the number of turns TNB of the base winding TNO of the emitter winding is TNB:TNO=1
:If the winding ratio is 10, there are no voltage dividing capacitors C3 and C4, and there is only a single capacitor C. If the capacitor C is
3, if C4 is present, the fluctuating voltage is, for example, C3=C4
In this case, it is possible to reduce the input voltage fluctuation by 0.5V, which is half of that value. The amount of relaxation can be set to a desired value by appropriately selecting the winding ratio or the value of the capacitor within a range in which the transistor Q can sufficiently operate.

In this way, the voltage divider circuit performs two functions: temperature compensation and input voltage fluctuation compensation, and it is possible to ensure that the transistor Q operates efficiently and to prevent thermal breakdown. As described in detail above, this invention has a one-channel inverter circuit in which the collector of the transistor is grounded, and the voltage dividing point of a voltage dividing circuit consisting of a capacitor connected in parallel to the base winding is connected to the base. The capacitors of the voltage divider circuit configured with the above-mentioned voltage divider circuit were selected with different temperature characteristics so that the voltage at the voltage divider point decreases as the temperature rises. A stable secondary output is obtained, and since the voltage generated in the base winding is divided by a capacitor and fed back to the base of the transistor, input voltage fluctuations can be alleviated. Since the base current is selected to be constant regardless of the current, it is possible to prevent the transistor from becoming oversaturated more than necessary, ensuring stable oscillation operation, and having the excellent effect of preventing the transistor from thermal breakdown.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of a conventional ignition system, Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is a characteristic diagram of a voltage dividing capacitor used in this invention, and Fig. 4 is a circuit diagram showing an example of a conventional ignition system. FIG. 2 is a circuit diagram showing a partial circuit example of a conventional ignition device. Q...Transistor, T...Transformer, N8...Base winding, NE...Emitter winding, C1-C5...Capacitor, A・・・・・・
...Voltage dividing circuit, a... Voltage dividing point, Dl, D2...
...Diode, Rl, R2...Resistance, N
2...Secondary winding.

Claims (1)

[Claims] 1. In a one-stone inverter circuit comprising a transistor provided on the primary side of a transformer having a base winding, an emitter winding, and a secondary winding on the primary side, the transistor has its collector grounded and is connected to the emitter winding of the transistor load. A resonance capacitor is connected, one capacitor of a voltage divider circuit consisting of two capacitors connected in series is connected to the base winding, and the voltage divider circuit is connected in parallel to the base winding. A voltage dividing point of the circuit is connected to the base of the transistor, and the other capacitor of the voltage dividing circuit is connected to the emitter of the transistor so that the voltage across the capacitor is applied between the base and emitter of the transistor, and An ignition device characterized in that the two capacitors of the voltage dividing circuit are selected with different temperature characteristics so that the voltage at the voltage dividing point decreases as the temperature rises.