A diesel engine intake cam profile creates two intake valve events separated
by
a short dwell period each engine cycle. A relatively low valve lift during an engine
exhaust event allows a portion of the exhaust gas to flow into an intake manifold
and mix with intake air. The intake valve is then nearly closed for a dwell period
until a normal intake valve opening occurs, drawing the mixture of air and exhaust
gas back into the combustion chamber for compression and burning, upon closure
of the intake valves.
