Past exhaust emission control systems have failed to cool the exhaust gas
prior to mixing with the intake air. The present exhaust gas
recirculation system cools a flow of exhaust gas with a common coolant
being used to cool an engine prior to mixing the flow of exhaust gas with
a flow of intake air. The present exhaust gas recirculation system
includes a control system for monitoring an operating parameter of an
engine. The control system interprets a signal sensing the operating
parameter within a controller and the controller causes an exhaust valve
regulator to move between an open position and a closed position.
Additionally, a plurality of paths or maps, for example, one being a
normal coolant temperature strategy and another being a high coolant
temperature strategy is used. In the normal coolant temperature strategy,
with the exhaust valve regulator in the open position the supply of fuel
to the engine would be advanced. And, in the high coolant temperature
strategy, with the exhaust valve regulator in the closed position the
supply of fuel to the engine would be retarded. Thus, the emissions
emitted from the engine are maintained within a preestablished parameter.