Patent ID: 6041754
Filing Date: 2000-03-28
Classification: F02M

Abstract:
An idle intake control device of an internal combustion engine comprising:an idle intake passageway for connecting an upstream side and downstream side of an intake regulating valve provided in the intake passageway of said engine so as to pass idle intake air for idling of the engine;an idle intake regulating valve provided in a middle section of the idle intake passageway to regulate the flow rate of the idle intake air passing through the idle intake passageway and fed to said engine; andat least one backflow preventing means, said backflow preventing means (i) positioned in the vicinity of said idle intake regulating valve, and (ii) for preventing backflow of the idle intake air in said idle intake passageway without substantially preventing the flow of the idle intake air and producing only a forward flow of idle intake air near said idle intake regulating valve so as to prevent the idle intake air existing near an outlet opening of said idle intake passageway from flowing back in said idle intake passageway accompanied by combustion products, reaching said idle intake regulating valve, and causing combustion products to adhere to said idle intake regulating valve;wherein said backflow preventing means is a restrictor portion provided in said idle intake passageway at the downstream side of said idle intake regulating valve, and an inner wall surface of the restrictor portion and an inner wall surface of said idle intake passageway at the upstream side and downstream side thereof are connected by a smooth surface with no step differences.