Valves and valve actuation – Rotary valves – Butterfly
Patent
1998-11-13
2000-04-11
Fox, John
Valves and valve actuation
Rotary valves
Butterfly
123337, F16K 122
Patent
active
060479507
DESCRIPTION:
BRIEF SUMMARY
The invention relates to throttle valve bodies for a fuel injection device of an internal combustion engine and has, more particularly, as its subject a throttle valve body comprising a housing, in which an air intake duct is formed, and comprising a flap in the form of a substantially circular or slightly elliptic disk, which is mounted on a center axis of rotation transverse to the duct and which is displaceable between a minimum, if appropriate zero, opening position and a maximum opening position, in which the plane of the flap is oriented substantially parallel to the axis of the intake duct, in order to regulate the airflow which is admitted into the engine and to which the fuel quantity injected for each engine cycle must be linked.
The most commonly used throttle valve bodies comprise a flap, in the form of a thin circular disk of constant thickness, and a duct in the form of a circular cylinder in the zone where the flap pivots, the passage cross section offered to the air between the flap and the wall of the duct varying rapidly from the minimum opening position of the flap during the initial angular displacement of the latter, above all when said minimum opening position is virtually zero.
Now in order to control the engine satisfactorily, that is to say so as to ensure driving comfort, under low loads (that is to say, for small openings of the flap), the initial increase in the passage cross section as a function of the position of the flap must be highly progressive.
In order to obtain the requisite progressiveness, bodies have already been provided which use a flap of complex shape (FR-A-2,674,573), which is much less advantageous than the conventional flap in the form of a simple disk, and/or a duct, the wall of which has at least one portion of complex shape (FR-2,663,710 and FR-A-2,694,963), which is costly to produce by the machining and/or casting of metal parts or which is difficult to produce by molding synthetic materials because of the need to use multiple or removable cores.
FR-A-2,674,573 describes a throttle valve body, as defined above, in which that side of the flap which rotates upstream from the minimum opening position has, on its downstream face, a bulge of a cross section (in a plane orthogonal to the axis of rotation) sufficiently small to allow the flap to rotate. That side of the flap which rotates downstream during opening and the duct cross section downstream of the minimum opening position of said side rotating downstream have, in general terms, shapes which cooperate in order to impart to the cross section for the passage of air between them a law of variation as a function of the angle of rotation, the initial gradient of which is lower than the maximum gradient of the law of variation during opening. This is obtained by causing to rotate, in an intake duct in the form of a circular cylinder in the zone of rotation of the flap, a flap, of which the side which rotates downstream during opening carries, on its upstream face, a bulge which may be symmetrical, with respect to the axis of rotation, to that on the downstream face of the flap side rotating upstream, each bulge being a flyweight attached to the flap or a shoulder in one piece with the latter, the edge of bulge having a profile selected so as to slow the increase in the passage cross section during the initial opening of the flap.
However, it is also possible for the flap side rotating downstream to be in the form of a thin half disk and for the intake duct to have, from the minimum opening position of the flap, a portion with a circular cross section decreasing downstream, thus causing a flap of complex shape to cooperate with an intake duct having a wall of complex shape.
FR-2,663,710 describes a throttle valve body, as defined above, the intake duct of which has, both upstream and downstream of the axis of rotation, a portion, one half of which is semicircular and of constant radius and the other half of which has, at each level along the axis of the intake duct, a cross section in the form of an ellipse,
REFERENCES:
patent: 5315975 (1994-05-01), Hattori et al.
patent: 5374031 (1994-12-01), Semence et al.
patent: 5749336 (1998-05-01), Tanaki et al.
Pontoppidan Michael
Semence Pierre
Fox John
Magneti Marelli France
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