Internal-combustion engines – Poppet valve operating mechanism – Electrical system
Reexamination Certificate
2000-11-08
2001-10-16
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Electrical system
C123S090160, C123S090170, C123S090600, C123S090650
Reexamination Certificate
active
06302069
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the field of internal combustion engines, more particularly to a method of controlling the engine intake and exhaust valves so as to produce a more efficient combustion process within the cylinder and to operate the engine as a pneumatic hybrid.
This invention describes a method for increasing the flexibility of the present valve control. While the general principles and teachings disclosed are applicable to all valve controlled internal combustion engines, the invention is hereinafter described in detail in connection with its application to a reciprocating, cam and valve, multi-cylinder engine.
The poppet valve driven by a camshaft has been used in the internal combustion engine for many years. Modifications to the valve train have been developed to permit changing the valve timing while the engine is in operation. When the timing control prevents the valves from opening during an engine cycle, the cylinder is disabled, and the effect of a variable displacement engine is obtained. The advantage of a variable displacement engine is that when less than maximum efficiency power is required, some of the cylinders may be disabled and the remaining active cylinders' power is increased so that they will operate at greater efficiency, while the engine output remains constant. This approach has had limited success in practice because the usual control activates or deactivates half the number of cylinders, and this abrupt change in output torque causes poor drivability. Furthermore, the disabling mechanism is relatively slow acting so that more than one revolution of the crankshaft is required to make the change.
All of the differences cited with the prior art referenced in my previous applications (Ser. Nos. 09/519,635 & 09/585,778) apply to the present invention. Another example of prior art is the FINGER FOLLOWER ROCKER ARM SYSTEM in U.S. Pat. No. 5,653,198 by Diggs issued Aug. 5, 1997. This invention describes a disabler mechanism controlled by a rotary solenoid with the camshaft providing the power to move the valve. The rotary solenoid shifts the follower away from the cam so no force is transmitted to the valve stem. The shape of the cam lobe still determines the valve action when activated. The intent of the invention is to engage and disengage the cam during the time when the valve is inactive as shown in
FIG. 7
, because of the high forces involved with valve action. The conventional cam lobe is shaped to accelerate and decelerate the valve at a given time in the engine cycle, and this system cannot change those times. The present application does not have these limitations. The spring energy taken from the camshaft is stored for release at any time to separately open and close the valve, and the valve accelerations are determined by the interchange of energy between two springs. The resonant oscillation between the two springs insures a “soft” valve landing at the oscillation extremes whenever the springs are released.
BRIEF SUMMARY OF THE INVENTION
The object of this invention is to improve the response of the engine intake and exhaust valves to electrical signals of the engine controller which directs a valve to open or close. A further object is to have the camshaft supply the power to move the valves. A further object is for the valves to operate rapidly, and be independent of engine speed in their response time. A further object is have the valves operate with minimum opening and closing impact, noise, and vibration. A further object is to be able to open and close the valves anywhere within at least 630 degrees of two crankshaft rotations. A further object is to allow the camshaft to rotate at crankshaft speed to facilitate two cycle compressor and air motor operation of the engine as a pneumatic hybrid.
The present invention accomplishes these objects in an improvement on my previous referenced applications. It uses only one of the holding solenoids previously described, together with a double acting solenoid which can be activated to hold its plunger in two different positions. Further, it shows a unique method of resuming operation after the electrical power to the engine has been shut down from the previous operation.
REFERENCES:
patent: 4870930 (1989-10-01), Yagi
patent: 4917056 (1990-04-01), Yagi et al.
patent: 4930463 (1990-06-01), Hare, Sr.
patent: 5653198 (1997-08-01), Diggs
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