Rotational speed detecting apparatus for electronically-controlled fuel injection systems

摘要

A rotational speed detecting apparatus for controlling the operation of an electronically controlled fuel injection system in accordance with the rotational speed of an engine. A reference pulse generator is connected to generate a reference pulse signal in synchronism with a pulse signal which is generated by the fuel injection system in substantial synchronism with the rotation of the engine. The reference pulse generator is further connected to change the time width of the reference pulse signal in response to the operation of a starter motor and a throttle valve so that it represents the predetermined rotational speeds of the engine. A comparison circuit is connected to compare the one cycle period of the pulse signal with the time width of the reference pulse signal. The output signal of the comparison circuit is applied to the fuel injection system so that it controls fuel enrichment and fuel cut-off operation of the fuel injection system.