LOST MOTION VARIABLE VALVE ACTUATION SYSTEM FOR ENGINE BRAKING AND EARLY EXHAUST OPENING

摘要

A method and system for actuating an internal combustion engine exhaust valve to provide compression release actuation during an engine braking mode of engine operation and early exhaust valve opening actuation during a positive power mode of engine operation is disclosed. The system may include a first cam having a compression release lobe and an early exhaust valve opening lobe connected to a hydraulic lost motion system including a first rocker arm. A hydraulically actuated piston may be selectively extended from the hydraulic lost motion system to provide the exhaust valve with compression release actuation or early exhaust valve opening actuation. The hydraulically actuated piston may be provided as a slave piston in a master-slave piston circuit in a fixed housing, or alternatively, as a hydraulic piston slidably disposed in a rocker arm. The method and system may further provide exhaust gas recirculation and/or brake gas recirculation in combination with compression release actuation and early exhaust valve opening actuation.