Patent ID: 8616178

Claim:
An engine braking system comprising: an engine braking controller responsive to an engine brake command; an exhaust control path between an engine cylinder and an exhaust discharge path; a valve element located within the path, the valve element operable between a closed position to close the exhaust control path and a fully open position to open the exhaust control path, the valve element having at least one face exposed to the engine cylinder wherein cylinder pressure during engine braking exerts an opening force on the valve element; a retainer arranged to be positioned in two operating positions, a first operating position which abuts the valve element to prevent opening of the valve element and a second operating position which clears the valve element to allow opening of the valve element; and an actuator engaged with the retainer and signal-connected to the braking controller to move between a first position and a second position to move the retainer between the first and second operating positions.