Vaporized fuel control apparatus for internal combustion engines

Claim 1

A vaporized fuel control apparatus for an internal combustion engine, which is adapted to discharge fuel vapor formed in a fuel tank into an intake system of an engine, said apparatus comprising: a refuelling canister for adsorbing fuel vapor formed in said fuel tank during a refuelling thereof; a running canister for adsorbing fuel vapor formed in said fuel tank during a running of said engine; a first electromagnetic valve provided in a path for discharging the fuel vapor adsorbed by said refuelling canister into said intake system of said engine for selectively controlling said discharging; a second electromagnetic valve provided in a path for discharging the fuel vapor adsorbed by said running canister into said intake system of said engine for selectively controlling said discharging; first setting means for setting a valve duty cycle of said second electromagnetic valve; second setting means for setting a valve duty cycle of said first electromagnetic valve at a value equal to one nth, where n is an integer not smaller than 2, of the valve duty cycle of said second electromagnetic valve set by said first setting means; and output means for outputting electrical signals to said first and to said second electromagnetic valves in parallel, one of said electrical signals being representative of said valve duty cycle of said first electromagnetic valve set by said second setting means, and an other electrical signal representative of said valve duty cycle of said second electromagnetic valve set by said first setting means respectively.