Patent ID: 9267458
Filing Date: 2016-02-23
CPC Classification: F02D,G01M,Y02T

Claim Text:
1. A control apparatus for a general purpose engine comprising: a variety of kinds of sensors that generate detected values corresponding to a load and a rotational speed of the general purpose engine; a three-way catalyst that is arranged in an exhaust passage of said general purpose engine; an O2 sensor that is arranged at the upstream side of said three-way catalyst; a basic injection amount calculation unit that calculates a basic amount of fuel to be injected to said general purpose engine based on the individual detected values of said variety of kinds of sensors; a first air fuel ratio determination unit that determines, based on a comparison of an output value of said O2 sensor with a rich-lean determination voltage, whether an air fuel ratio of a mixture is rich or lean; a fuel injection amount correction unit that carries out feedback correction of said basic fuel injection amount to a value corresponding to a stoichiometric air fuel ratio in accordance with a result of the determination of said first air fuel ratio determination unit; a fuel injection control unit that supplies fuel to said general purpose engine so as to make it match a corrected fuel injection amount calculated by said fuel injection amount correction unit; a second air fuel ratio determination unit that determines, based on a comparison of the output value of said O2 sensor with a rich determination voltage or a lean determination voltage, whether the air fuel ratio of the mixture is rich or lean; a rich lean period calculation unit that calculates a rich lean period of the output value of said O2 sensor in accordance with a result of the determination of said second air fuel ratio determination unit; and a misfire determination unit that determines the presence or absence of a misfire in said general purpose engine based on said rich lean period of the output value of said O2 sensor, wherein said fuel injection control unit stops the injection of fuel to said general purpose engine, in cases where it is determined by said misfire determination unit that there is a misfire.