Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-08-10
2001-11-27
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090120, C123S090490
Reexamination Certificate
active
06321706
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the operation of a reciprocable valve of an internal combustion engine. More particularly, this invention relates to a system for selectively varying the rate at which a valve closes from its fully open position.
2. Description of the Prior Art
As is known in the art, for example, as taught by U.S. Pat. No. 5,002,023 (Butterfield et al.), which is assigned to the assignee of this application and the disclosure of which is incorporated by reference herein, the opening and closing of the reciprocable valves of an internal combustion engine, both the intake valves and the exhaust valves, is customarily actuated by irregularly-shaped cams on a rotating shaft, called a camshaft, whose rotation is effected by a chain or belt drive that connects the camshaft to the engine crankshaft, or to another camshaft in a dual camshaft engine. Typically, each valve is spring-biased against a cam of a camshaft, and its opening and closing cycle is precisely determined by the configuration of the cam against which the valve is spring biased. Occasionally, however, it would be advantageous to engine operation to delay the closing of a valve from a pattern it would otherwise follow if it remained in contact with the cam toward which it is spring biased, and to be able to do so selectively.
SUMMARY OF THE INVENTION
According to the present invention, there is provided an apparatus and a method for delaying the closing of an internal combustion engine, cam actuated valve from the rate it would otherwise follow based on contact with a cam of a camshaft against which the valve is resiliently biased. The apparatus and method may take the form of one or another of various embodiments, either hydraulic and/or electric, and most such embodiments permit the delayed closing of the valve to occur selectively, that is, only when desired.
Accordingly, it is an object of the present invention to provide an apparatus and a method for delaying the closing of an internal combustion engine, cam actuated valve from the rate it would otherwise follow based on contact with the cam against which the valve is resiliently biased. More particularly, it is an object of the present invention to provide an apparatus and a method of the foregoing character in which the delayed closing of the valve occurs selectively, that is, only when desired.
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patent: 5943989 (1999-08-01), Kira
Borg-Warner Inc.
Dziegielewski Greg
Emch, Schaffer, Schaub & Porcello & Co., L.P.A.
Lo Weilun
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