Internal combustion engine function control system

An internal combustion engine function control system comprising first and second signal generating means mechanically driven by the engine, said first signal generating means producing a train of signals at a first frequency equal to the required function frequency, and the second signal generating means producing a train of signals at a second frequency which is a multiple of the first frequency, engine parameter sensitive means for varying the phase of the first signal train relative to that of the second signal train between limits such that the combined ordinal succession of the signals is maintained constant, and function timing means for causing triggering of an output circuit at the end of a delay following the generation of a signal from said first signal generating means, such delay consisting of the sum of a first delay equal to the period between the generation of said signal from said first signal generating means and the generation of a selected one of said train of signals produced by said second signal generating means and a second delay, the first and second delays being determined by the frequency and phase relationship of the two signal trains.