Importance

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Abstract

Apparatus and method are disclosed for converting an internal combustion engine from a normal engine operation (20) to an engine braking (or retarding) operation (10). The engine has an exhaust valve train containing two exhaust valves (300), a valve bridge (400) and an exhaust valve lifter (200). The apparatus has an actuation means (100) including a hydraulic system integrated into the exhaust valve train. The hydraulic system contains a braking piston (160) slidably disposed in the valve bridge between an inoperative position (0) and an operative position (1). In the inoperative position, the braking piston is retracted and the actuation means disengaged from the normal engine operation. In the operative position, the hydraulic piston is extended and the actuation means opens one of the two exhaust valves (300a) for the engine braking operation. The apparatus also includes engine brake reset means (150) for modifying the valve lift profile generated by the enlarged normal cam lobe (220) when the small braking cam lobes (232) and (233) are integrated into the normal exhaust cam (230). The apparatus also has a control means (50) for moving the actuation means between the inoperative position and the operative position.

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First Claim