Caterpillar Tractor Co.

Darrell E Stafford

Alexander Goloff

Frank E Keske

Michael K Stratton

An internal combustion engine including at least one cylinder defining a combustion chamber, a piston reciprocal within the cylinder, at least one port in the combustion chamber, a valve within the port and movable between positions opening and closing the port, a camshaft, a valve train operated by the camshaft for moving the valve between the positions, the valve train including a hydraulic valve lifter, an oil supply line for providing oil to the hydraulic valve lifter and a device for at least partially interrupting the supply of oil to the hydraulic valve lifter for predetermined operational conditions of the engine to thereby intentionally induce valve lash into the system at the predetermined operational conditions. At low engine speeds or during cranking for startup, the induced valve lash increases compression to maximize engine efficiency at low speeds or during startup, while at overspeed conditions, prevents valve train separation and/or lifter pumpup to prevent interference between valves and pistons which would damage the engine.

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Peoria, IL, United States of America

Darrell E Stafford