GB833010A - Improvements in or relating to ignition apparatus for internal combustion engines - Google Patents

Abstract

833,010. Ignition systems. WESELCO Ltd. Feb. 5, 1957 [July 4, 1956], No. 3911/57. Class 7(4) An ignition system for an internal combustion engine comprises a transistor, means for coupling an output circuit of the transistor to an input circuit thereof whereby the transistor is adapted to produce high frequency oscillation, means for inhibiting the production of the oscillation, means comprising an electric impulse generator operating in synchronism with the engine for periodically overriding the inhibiting means, thus rendering the transistor effective to produce the oscillations and means for feeding the oscillations at high voltage to a spark plug for the engine. In Fig. 1 electrical pulses are produced by a rotor 3 which periodically breaks .the magnetic circuit 2. The pulses are fed to a blocked high frequency oscillator 8 which is shown in detail in Fig. 3. The pulses release the oscillation and oscillations are fed to a phase-shifting network 9 and amplifier 10 and thus to the sparking plugs by way of a transformer 11, 12. The network 9 alters the phase of the oscillations as a function of the pulse recurrence frequency. Thus an ignition advance will be obtained which is proportional to the engine speed. As shown, Fig. 3, the oscillator 8 and the amplifier 10 comprise a PNP junction transistor The reference 20 indicates a resistor or thermistor. Fig. 4 shows a modified oscillator and the amplifier is dispensed with in this embodiment. In a modification of Fig. 1 pulses are supplied to the oscillator 8 by way of a filter or equalizer. The filter or equalizer is employed to compensate for the variations in the induced voltage of the pulses as a function of the velocity of rotation of the magnetic rotor i.e. of the engine speed. Tetrode transistors may be substituted for the conventional junction transistors shown.