Desmodromic valve system including single cam surface for closing and opening the valve

Abstract

A desmodromic valve and cam system is provided. The system may comprise a cam lobe mounted to a cam shaft and defining an effective cam surface. The system may also comprise a rocker mounted to a valve wherein the rocker pivots up and down in response to an input of the cam lobe to close and open the valve. More particularly, the effective cam surface of the cam lobe pushes up on the rocker follower surface to close the valve and pushes down on the rocker follower surface to open the valve.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefits of U.S. Provisional Patent Application Ser. No. 60 / 843,074, filed on Sep. 8, 2006, the entire contents of which are expressly incorporated herein by reference.STATEMENT RE: FEDERALLY SPONSORED RESEARCH / DEVELOPMENT[0002]Not ApplicableBACKGROUND[0003]The present invention relates to desmodromic valve and cam systems for internal combustion engines with intake and exhaust valves, and more particularly, to a rocker which regulates the opening as well as the closing of the valve.[0004]Most conventional internal combustion piston driven engines utilize valve trains to induct an air / fuel mixture into the cylinders and to expel the burned air / fuel mixture from the cylinders. Typically, each cylinder is assigned at least one intake valve and at least one exhaust valve. The valves are typically pushed down by rockers thereby opening the valve and pushed upwardly by springs thereby closing the valve. In a convent...

AI Technical Summary

Benefits of technology

"The present invention is a desmodromic cam and valve system that can be retrofitted onto conventional engines. It includes a rocker with opening and closing follower surfaces that define the desired valve performance characteristics in terms of timing and duration. A cam lobe is attached to the cam shaft and rotates to pivot the rocker up and down. The system also includes a plurality of rockers with different opening and closing follower surfaces to adapt the performance of the engine to different uses. The rockers can be easily disassembled and installed without having to disassemble the cam shaft. The technical effects of this invention include improved valve timing and lift, improved engine performance, and flexibility in adapting the engine performance to different uses."

Problems solved by technology

Most notably, pushing the valves open against the force of the springs consumes engine power.

Another disadvantage is that because the cam mechanism cannot afford to have any “bounce” from the springs, the cam profile has to be somewhat gentle, i.e., it must gently push the valve, but never shove it.

Another disadvantage is that when the motor is turned at high RPM's, the valves can “float” and hit the piston.

As a result, the valves will often stay open and / or “bounce” on their seats.

To overcome these disadvantages, innovative desmodromic valve trains have evolved over about the last century; however, in a very slow technological pace and in most applications with little or limited success.

One disadvantage of prior art desmodromic valve train systems is that they have not been adapted to be installed or “retrofitted” into existing modern conventional engines.

Unfortunately, however, most manufacturers are not willing to invest the sizeable amounts of capital to build such desmodromic engines, or much less, market vehicles with engine platforms which have not been proven or which have had a past history for reliability problems.

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