RPM control apparatus for internal combustion engine

Claim 1

An RPM control apparatus for an internal combustion engine for controlling RPM fluctuations of the engine comprising: a target RPM generator for generating a target value of a no-load RPM on the basis of engine operating conditions; a sensor for detecting at least one of a suction air quantity and a suction pipe pressure and generating signals representative thereof; an RPM adjuster for generating an RPM adjustment signal for a target suction air quantity signal and a target suction pipe pressure signal for the engine on the basis of a relationship between the RPM of the engine and a target RPM represented by the target value; a first limiter for limiting at least one of said target suction air quantity signal and said target suction pipe pressure signal within a predetermined range and for generating an output; a suction adjuster for generating an adjustment signal output on the basis of a relationship between at least one of the suction air quantity signal and the suction pipe pressure signal and the output of said first limiter; a second limiter for limiting the output of said suction adjuster within the predetermined range; and a suction control valve receiving the output of said second limiter for controlling RPM fluctuations.