Fuel injection device

Claim 1

A throttle body adapted to be mounted between an intake pipe and an intake manifold, said throttle body comprising: an upstream body connected to said intake pipe and formed with a substantially horizontal suction passage; a downstream body connected to said intake manifold and formed with a downwardly inclined throttle bore, said throttle bore continuously extending from said suction passage on a downstream side thereof; a throttle valve rotatably mounted to a substantially horizontal throttle shaft in said throttle bore of said downstream body; a projection formed on an inner wall surface of said throttle bore at a lower portion thereof at a position just downstream of said throttle valve such that rotation of said throttle valve is not hindered; and a fuel injector mounted to said upstream body in such a manner as to inject fuel toward said projection; wherein when an opening angle of said throttle valve is small, the fuel injected from said injector collides with a lower portion of said throttle vale to be atomized, and the fuel scattered downwardly from said throttle valve onto the inner wall surface of said throttle bore is allowed to smoothly flow downstream owing to the downward inclination of said throttle bore, thereafter being sucked into an engine by an intake manifold vacuum created downstream of said throttle valve, while when the opening angle of said throttle valve is large, the fuel injected from said injector collides with said projection to be atomized, thereafter being sucked into said engine.