Elongated spark ignition system

Abstract

The aim of this thesis was to analyse the theory and eventually to design an electronic spark elongated system. The basic idea of this system was to feed, not a single spark as in conventional system, but a series of sparks, near the end of the compression stroke. In order to understand the requirements of such an ignition system; the baste principles of combustion, in internal combustion engine; were first studied. Then the theory and functional details of the conventional ignition system and transistorised ignition were covered to the extent of forming a good background to the theory and design of the spark elongated system. such a system based on transistorised ignition, was then built. In this circuit the traditional break points switch was retained but later it was replaced by an opto-electronic switch which controls the circuit through a power transistor. The mechanical advance/ retard mechanisms, used in all conventional systems. were then substituted by electronic techniques, using the opto-electronic switch as an integral part of this latter refinement. The capacitor discharge ignition system, which like the transistorised system, is a development of the conventional ignition, was also considered with aim of extending the elongated spark system to this type of ignition. But it was found that such a system could not be adapted to the multiple spark system because of its low frequency response.