Patent ID: 8272363

Claim:
A compression-release brake system for operating at least one exhaust valve of an internal combustion engine during a compression-release engine braking operation, said system comprising: a self-contained compression brake control module operatively coupled to at least one exhaust valve for controlling a lift and a phase angle of at least one exhaust valve; and said compression brake control module provided to maintain said at least one exhaust valve open during a compression stroke of the engine when said engine performs the compression-release engine braking operation; said compression brake control module including: a casing including a single-piece body defining a piston cavity and an actuator cavity being in fluid communication with each other through a connecting passage in said body; a slave piston slidingly mounted within said piston cavity for reciprocating within said piston cavity between an extended position and a collapsed position, said slave piston being provided to engage said at least one exhaust valve in said extended position thereof; a supply conduit formed within said body of said casing and connected to said connecting passage, said supply conduit adapted to provide pressurized hydraulic fluid to said piston cavity through said connecting passage; a check valve provided between said connecting passage and said piston cavity to hydraulically lock said piston cavity when a pressure of the hydraulic fluid within said piston cavity exceeds the pressure of the hydraulic fluid in said supply conduit, said check valve biased closed by a biasing spring; and a compression brake actuator disposed in said actuator cavity for controlling said check valve; said compression brake actuator including an actuator element exposed to atmospheric pressure and slidingly mounted within said actuator cavity for reciprocating between an extended position, and a compression spring biasing said actuator element toward an extended position thereof in which said actuator element engages and opens said check valve solely by the biasing force of said compression spring so as to unlock said piston cavity and fluidly connect said piston cavity to said supply conduit; said single-piece body of said compression brake control module non-movably fixed to one of a cylinder head, a cylinder block of said engine and a dedicated brake rocker arm driven by a dedicated compression-release cam member for operating said at least one exhaust valve during the compression-release engine braking operation.