An exhaust gas recirculation (EGR) system for use in a four-stroke,
internal combustion, compression-ignition engine having at least one
engine cylinder, at east one combustion chamber, at least one intake
valve and a crankshaft. The EGR system includes at least one exhaust gas
intake valve that is opened during at least a portion of an engine intake
stroke when the exhaust gas pressure is greater than the pressure of gas
in the combustion chamber, thus allowing exhaust gas to flow into the
combustion chamber to establish internal EGR. A cam-operated intake
rocker arm assembly has the form of both a first class lever and a second
class lever. The first class lever directly communicates motion of the
intake rocker arm assembly to open the intake valve, and the second class
lever communicates motion of the intake rocker arm assembly through a
hydraulic transfer assembly to open the exhaust gas intake valve.