Compression-release engine brake system for lost motion rocker arm assembly and method of operation thereof

A method of operation of a compression-release brake system in a brake-on mode for operating at least one exhaust valve of an internal combustion engine during a compression-release engine braking operation, said compression-release brake system maintaining said at least one exhaust valve open during a portion of a compression stroke of the engine when performing the compression-release engine braking operation, said compression-release brake system comprising:

• an exhaust rocker assembly for operating said at least one exhaust valve, said exhaust rocker assembly including an exhaust rocker arm mounted about a rocker shaft and selectively pivotable to open said at least one exhaust valve;
• an actuation piston moveable between retracted and extended positions and slidably disposed in an actuation piston bore formed in said exhaust rocker arm, said actuation piston operatively coupled to said at least one exhaust valve when in the extended position;
• said actuation piston defining an actuation piston cavity within said actuation piston bore between said actuation piston bore and said actuation piston;
• a supply conduit formed within said exhaust rocker arm, said supply conduit configured to supply pressurized hydraulic fluid to said actuation piston cavity to displace said actuation piston to the extended position when there is a gap between said actuation piston and said at least one exhaust valve;
• and
• an exhaust valve reset device mounted to said exhaust rocker arm and including a reset check valve disposed between said supply conduit and said actuation piston cavity to hydraulically lock said actuation piston cavity by closing said reset check valve when a pressure of the hydraulic fluid within said actuation piston cavity exceeds the pressure of the hydraulic fluid in said supply conduit;
• said method comprising the steps of:
• mechanically biasing said reset check valve closed during a first part of a valve brake lift of said at least one exhaust valve during a compression stroke of the internal combustion engine;
• hydraulically biasing said reset check valve closed during a second part of a valve brake lift of said at least one exhaust valve following the first part during the compression stroke;
• and
• resetting said at least one exhaust valve during an expansion stroke of the engine by opening said reset check valve and releasing hydraulic fluid from said actuation piston cavity to close said at least one exhaust valve.