Patent ID: 6047950
Filing Date: 2000-04-11
Classification: F02D

Abstract:
A throttle valve body for a fuel injection device of an internal combustion engine, said body comprising:a housing in which an air intake duct is formed and a flap having the form of a substantially circular disk said flap being mounted on a central rotation shaft extending transversely with regard to said duct, said flap being displaceable by pivoting with said rotation shaft on an opening angle between a minimum opening position and a maximum opening position in which said flap is oriented substantially parallel to an axis of said duct, said flap having a first side part which rotates upstream from said minimum opening position, said first side-part being substantially in the form of a flat half disk and said intake duct having a wall which, on the same side as said flap first side-part and upstream of said minimum opening position of said flat, has an evolutive surface portion cooperating with said flap first side part, such that, at the start of an opening displacement of said flap, a passage delimited between said flap and said evolutive surface portion has a cross section increasing as a function of said opening angle less rapidly than in the case of a cylindrical air intake duct,wherein said evolutive surface portion has, at each level along said duct axis and over a first duct cross section half which extends on the same side of said duct axis as said flap first side part, a cross section substantially in the form of a half ellipse, having a minor semiaxis, perpendicularly to said rotation shaft, which decreases progressively as for as definite opening angle of said flap, while upstream of said evolutive surface portion and over said first duct cross section half, as well as over a second duct cross section half on the same side as a second side part of said flap which rotates downstream during opening and as far as a level position, along said duct axis, which corresponds to a downstream edge of said evolutive surface portion, said duct has a wall which is convergent, said flap second side part having an upstream face on which there protrudes a shoulder with an edge having a profile selected so as to slow the increase of said passage cross section during the initial flap opening, with respect to a flap second side part in the form of a flat half disk rotating downstream in a cylindrical duct, said intake having, downstream of said minimum opening position of said flap, a downstream and divergent portion as far as an outlet of said duct.