Throttle body for an internal combustion engine and its manufacturing method and a throttle apparatus using the same

摘要

A hot water conduit (40) is formed between an inner cylinder (20) and an outer cylinder (30). A gasket (50) seals an annular opening (40a) of the hot water conduit (40) facing to a surge tank (100). Hot water is supplied into the conduit (40) from an engine cooling water passage. Heat of the hot water is effectively transferred to the entire vicinity or surrounding of a throttle valve (14), thereby effectively avoiding icing phenomenon of the throttle apparatus.