US Patent 7201145 Fuel supply apparatus for internal combustion engine

In a fuel supply apparatus for an internal combustion engine including a first fuel injection valve for directly injecting a fuel into a cylinder and a second fuel injection valve for injecting the fuel into an intake manifold, production of deposits in the first fuel injection valve is prevented and a satisfactory homogenous air-fuel mixture can be formed during homogenous combustion while an engine is at idle. In order to achieve this effect, during homogenous combustion while the engine is idle, a second fuel injection valve injects the fuel and a first fuel injection valve injects the fuel to which pressure has been applied by a low-pressure pump, without a high-pressure pump applying further pressure to the fuel.