| 摘要 |
A rotary valve is disclosed suitable for replacement of poppet valves. The valve is temperature controlled through a combination of heat transfer techniques and means for reducing heat transfer between gas flows and the valve components. Assymetric geometry is used in the seals to reduce wear and friction, and a removable combustion chamber in the valve housing is used to facilitate fabrication, servicing and performances. A prototype of the valve was developed for a 30 cubic inch displacement four-stroke spark-ignition engine. The gas seals and lubricated parts of the rotary valve have been found to remain below 400 degrees Fahrenheit during test runs wherein the valve controlled gas flows and has maintained a brake mean effective pressure of 108 to 121 psi for periods of up to an hour.The valve uses pure rotation, and can be dynamically balanced for operation to the peak RPM permissible with reciprocating pistons. A four-stroke engine converted to rotary valving needs very few parts. For example, a four cylinder automotive engine fitted with a spheroidal rotary valve system requires only 11 moving parts; namely a crankshaft, pistons and rods, the valveshaft and a timing belt to drive the valveshaft. The valve is applicable to new engine production and is also suitable as a cylinder head assembly for retro-fit to existing engines of the overhead camshaft type.
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