Ignition timing Ignition timing In a spark ignition internal combustion engine, Ignition timing refers to the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke. The need for advancing (or retarding) the timing of the spark is because fuel does not completely burn the instant the spark fires, the combustion gases take a period of time to expand and the angular or rotational speed of the engine can lengthen or shorten the time frame in which the burning and expansion should occur. In a
Saab Direct Ignition "IDM") which houses the ignition coils and electronics that measure cylinder ionization for use by the Trionic engine management system. Saab Direct Ignition Saab Direct Ignition is a capacitor discharge ignition developed by Saab Automobile, then known as Saab-Scania, and "Mecel AB" during the 1980s. It was first shown in 1985 and put into series production in the Saab 9000 in 1988. One of the first instances of using the system was for a Formula Three racing engine (on B202 basis) developed with the help of engine builder John Nicholson, first shown in the spring of 1985. The system has