1. Field of the Invention (Technical Field)
The present invention relates to waste gate valves for turbochargers used in internal combustion engines.
2. Backqround Art
A turbocharger is an exhaust-driven blower that forces air into the engine under pressure. Turbochargers are used on gasoline and diesel engines to increase power output, while often improving engine efficiency (fuel economy and emissions levels).
The waste gate is typically operated by a diaphragm assembly 250. The actuator diaphragm is typically connected to the intake manifold, typically via a vacuum hose connected to fitting 255. A spring in the assembly typically keeps the waste gate closed at lower intake manifold pressures. As pressure builds up in the manifold over a preset value, the diaphragm compresses the spring, which is typically connected to waste gate valve 230 via linkage 260, thus partially or fully opening the waste gate. This redirects the flow of a portion of the exhaust gas from the turbocharger into the waste gate passage and out into the exhaust system via outlet 210, thereby reducing the boost pressure. The waste gate may alternatively be actuated electronically, or by other mechanical means, in response to one or more desired parameters other than, or in addition to, the intake manifold pressure.
This rotation can be limited to less than one rotation by the addition of anti-rotation pin 60 to valve 30. When valve 30 rotates, pin 60 eventually contacts arm 50, which prevents further rotation. However, some rotation still exists, which eventually causes valve wear and failure. Even if pin 60 is integrated with valve 30, and not attached via welding or a similar technique, pin 60 is not robust enough to withstand the turbocharger environment and eventually fails, resulting in unrestrained rotation and faster valve failure. Further, the existence of pin 60 causes thermomechanical distortion of valve 30 in the area of pin 60, which causes further damage to valve 30. Thus there is the need for a robust, cost-effective mechanism for preventing any rotation of a waste gate valve.
The present invention is a turbocharger waste gate assembly comprising a waste gate valve comprising an oblong shaft and an arm comprising an opening for receiving said shaft. The opening is preferably oblong. The shape of the opening is preferably substantially the same as the shape of the shaft. The shaft is preferably integrally formed with the valve during manufacture, although it optionally may be attached to the valve. The waste gate assembly preferably further comprises a fastener disposed on the shaft. The fastener, preferably comprising a washer, preferably prevents the shaft from sliding out of the opening.
The invention is also a method of preventing rotation of a turbocharger waste gate valve, the method comprising the steps of providing a waste gate valve comprising an oblong shaft, disposing the shaft into an opening of an arm, and disposing a fastener on the shaft. The opening is preferably oblong. The shape of the opening is preferably substantially the same as a shape of the shaft. The providing step preferably comprises integrally forming the shaft with the valve during manufacture. The method preferably further comprises the step of attaching the shaft to the valve. The fastener, preferably a washer, preferably prevents the shaft from sliding out of the opening.
A primary object of the present invention is to reduce failure rates of turbocharger waste gate valves.
Another object of the present invention is to prevent rotation of waste gate valves.
A primary advantage of the present invention is that the anti-rotation mechanism provided is robust enough to withstand the operating environment of a turbocharger.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:
The present invention is a non-rotating turbocharger waste gate valve. As used throughout the specification and claims, “oblong” means having any non-circular shape or cross section, such as oval, elliptical, elongate, square, and the like.
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Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above, and of the corresponding applications, are hereby incorporated by reference.