Exhaust port insert
AssigneeGeneral Motors Corporation
InventorsJames G. Solomon, Thaddeus B. Lilly, Robert A. Bolton
Life of this patent
Estimating the term…
Abstract
A two stroke cycle engine has an engine block with a cylinder bore accommodating a piston. An exhaust port connects the cylinder bore to an outside of the engine block. An exhaust port control valve mechanism within the engine, according to this invention, includes a valve pivotally mounted in the exhaust port between the cylinder bore and the outside for rotation between an open position and a closed position. The valve defines an upper timing edge of the exhaust port. An insert fills a volume in the exhaust port between the valve and the outside, thereby improving flow efficiency of the exhaust port.
Claims7
In a two stroke cycle engine having
- an engine block,
- means defining a cylinder bore in the engine block and
- means defining an exhaust port through the engine block along an exhaust port axis from the cylinder bore to an outside of the engine block, an exhaust port control valve mechanism comprising:
- a valve pivotally mounted in the exhaust port between the cylinder bore and the outside for rotation between an open position and a closed position and defining a timing edge of the exhaust port, and
- an insert filling a volume in the exhaust port between the valve and the outside thereby improving flow efficiency of the exhaust port.
An exhaust system for a two stroke cycle engine having an engine block and means defining a cylinder bore in the engine block, the exhaust system comprising:
- means defining an exhaust port extending from the cylinder bore and through the engine block to an outside of the engine block and having
- a valve pocket at an end of the bore adjacent the cylinder bore and
- an exhaust port area,
- a valve pivotally mounted in the valve pocket for rotation between an open position and a closed position to control exhaust timing and defining an initial flow area less than the exhaust port area for exhaust gases entering the exhaust port from the cylinder bore, and
- an insert filling a volume in the exhaust port to establish a continuous exhaust flow area of the exhaust port from the valve to the outside of the engine block that is approximately equal to the initial flow area as defined by the valve in the open position.
Dependencies are inferred from the claim text.