Patent ID: 6964270

Claim:
An EGR system for use on an internal combustion engine, the EGR system comprising; at least one hydraulic master cylinder; a slave cylinder in fluid communication with the hydraulic master cylinder and having a slave piston; an EGR valve coupled to the slave piston and biased in a closed position: a hydraulic manifold in fluid communication with the at least one hydraulic master cylinder and the slave cylinder; a three-port control valve having a first port in fluid communication with the hydraulic manifold, a second port in fluid communication with a source of hydraulic fluid when the three-port control valve is in a first state, and a third port in fluid communication with a hydraulic fluid drain when the three-port control valve is in a second state, the second port having a check valve to prevent backflow of hydraulic fluid from the hydraulic manifold into the source of hydraulic fluid; and a mode control valve separating the hydraulic manifold and the slave cylinder, the mode control valve comprising: a check valve that permits fluid to flow from the hydraulic manifold into the slave cylinder, and a closeable bypass that, when open, permits fluid to flow from the hydraulic manifold into the slave cylinder and from the slave cylinder into the hydraulic manifold.