IC engine ignition system - uses sensing of marks on rotating part synchronised to cam shaft to derive speed signals using triggering counter

摘要

The ignition system has a rotating part synchronised with the cam shaft of the engine and provided with synchronisation marks of which each represents a given position of a piston with respect to the upper dead point in each piston stroke. The rotating part has further marks at a given angle to the synchronisation marks. Each synchronisation mark results in a synchronising pulse and each further mark results in a further pulse. The speed signal is derived from the time between a synchronising pulse and the next further pulse. The counting of the triggering counter occurs using clock pulses produced by a microprocessor.