Abstract: An electronic cylinder identification system is disclosed for identifying the occurrence of a predetermined cycle position for a reference cylinder and synchronizing fuel injection for a multi-cylinder engine in accordance thereto. A four cylinder engine rotates a rotary body having two 90 degree spaced peripheral projections and two stationary reluctance sensors are positioned 180 degrees apart about the body and sense the passage of the rotary body projections. Logic circuitry receives signals from the two sensors and determines which sensor is currently providing a logic pulse indicating the passage of a projection and which sensor previously provided such a pulse. The logic circuitry utilizes this information to identify the rotational position of the rotary body by differentiating between occurring identical sensor pulses based upon which sensor previously produced a pulse.

Abstract: Electronic engine synchronization and timing apparatus for use in controlling fuel injection and/or spark ignition for an internal combustion engine is disclosed. An engine crankshaft rotates a rotary body having a plurality of radial projections, and a single crankshaft reluctance sensor is utilized to provide pulses in response to the passage of these projections and thereby provide a signal related to crankshaft position. An engine camshaft rotates a rotary body with radial projections at half of the crankshaft speed, and a pair of camshaft sensors provide signals in response to the passage of the camshaft projections which are indicative of the rotational position of the camshaft.