To reduce unburned gas and introduce a new degree of freedom in a setting of a fuel device.
Primary air and secondary air respectively for combustion are supplied to an internal combustion engine by a main air supply passage having a carburetor and an auxiliary air supply passage. An air flow control valve inside the auxiliary air supply passage changes an air-fuel ratio supplied to the internal combustion engine under control by an electronic control unit. Process data detected by a sensor is processed by the electronic control unit programmed so as to operate the air flow control valve, operate an automatic starting device of the carburetor, and adjust a condition of an ignition timing. By changing an open valve time of the control valve based on the process data detected from an operation parameter of the internal combustion engine, a restrained amount of secondary combustion air is supplied to an air-fuel mixture.
BALEN CESARE
TROZZI LEONARDO
