Blow-bye gas return device for internal combustion engines

Claim 1

A blow-bye gas return device for an internal combustion engine, comprising: an intake pipe connected to an engine; an injection body having therein a fuel injector with an injection port and disposed relative to said intake pipe to inject fuel from said injector into the intake pipe, the fuel injector being so disposed relative to the injection body that an air intake passage is defined in the injection body around the fuel injector; a throttle body having a throttle valve therein and disposed relative to the injection body and the intake pipe such that the throttle valve throttles the flow of the fuel injected by said fuel injector before the flow enters the intake pipe, said throttle body and said injection body being formed integrally into a unitary body to define therein a flow passage communicating with said air intake passage at the upstream side and with said intake pipe at the downstream side; a hot-wire type air flow sensor mounted on one side of the air intake passage; and blow-bye gas return passage means connecting the engine to said unitary body to conduct blow-bye gas from the engine into said unitary body at a position upstream of the throttle valve, said blow-bye gas return passage means having a blow-bye gas discharge orifice which opens toward the upstream side of the air intake passage and at the upstream side of said injection port of the injector, said discharge orifice being located at a position where the dynamic pressure is low.