Trigger inputs

Hi, so if the synchronization to know what engine cycle is or which cylinder is firing and this sensor is usually driven from the camshaft because it runs at half of the crankshaft and this sends 1 signal, and the reference sensor is for engine speed from crankshaft, in the Nissan example why engine speed trigger input is from the camshaft and not crankshaft? Just design? Any reason? What happens with rotary engine design?

With the Nissan's other than the poor design of having the Crank position determined from the end of the Cam (probably the worst place to do so for accuracy, especially on the RB engines) the trigger wheel used on these engines is divided into two parts, and has a different pattern for the sync teeth (either one wide tooth or all differing widths) so that the ECU can determine where the Sync position is.

A Rotary engine runs as a two stroke cycle, so it doesn't need to use a sync sensor.

About the only reasons to do all the positioning sender's date from the camshaft are packaging (fitting it to the engine) and/or access. As Steven pointed out, the rear of a camshaft is about the worst possible place to take it from, not least because of the camshaft drive 'whip' and camshaft tortional twist.

With a WANKEL engine the rotor rotates at 1/3 the speed of the E-shaft (equivalent of the crankshaft) and there is a 'firing stroke' for every revolution.