United States Patent  [ii] Patent Number: 5,301,643
Garcyalny  Date of Patent: Apr. 12,1994
 LOW OIL SENSOR USING COMPRESSION RELEASE TO AFFECT ENGINE OPERATION
 Inventor: Gary J. Garcyalny, Milwaukee, Wis.
 Assignee: Briggs & Stratton Corporation,
 Appl. No.: 57,673
 Filed: May 5,1993
 Int. a.' F02B 77/00
 U.S. CI 123/198 D
 Field of Search 123/198 D, 182.1
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The engine protection device affects the engine operation when a low oil level is sensed by releasing substantially all of the compression pressure in the combustion chamber to prevent engine starting, to stop a running engine, or to reduce engine speed. The engine protection device includes a paddle or float whose movement is responsive to the crankcase oil level, an arm connected to the paddle or float, and a pivotable, yoke-type mechanical compression release mechanism that pivots in response to the movement of the arm. The compression release yoke has a first cam member that engages a valve tappet surface. When a low oil level is sensed, the paddle or float pivots the arm and the first compression release member, causing the first cam member to engage the tappet surface to substantially open the intake or exhaust valve. The invention may include a second, easy start compression release member that partially releases the compression pressure to promote engine starting. The second compression release member may be integrally formed with the first compression release member, or it may be a separate member.
24 Claims, 10 Drawing Sheets