Patent ID: 6973786

Claim:
A turbocharged compression ignition engine comprising: engine cylinders within which combustion occurs to run the engine; an intake system through which charge air is introduced into the cylinders; an exhaust system through which products of combustion from the engine cylinders are exhausted; a turbocharger having a turbine in the exhaust system and a compressor in the intake system; a fueling system for fueling the cylinders; an exhaust gas recirculation system for conveying exhaust gas from the exhaust system to the intake system and comprising a direction control valve having an outlet, a first inlet communicated to the exhaust system upstream of the turbine, a second inlet communicated to the exhaust system downstream of the turbine, and an element that selectively communicates the inlets to the outlet to provide exhaust gas from a selected inlet to the outlet, a cooler through which exhaust gas passes after leaving the direction control valve outlet, a first EGR valve and a second EGR valve each having a respective inlet to which exhaust gas that has passed through the cooler is delivered, the first EGR valve being operable, when the direction control valve is selecting the first inlet, to control flow of recirculated exhaust gas to a location in the intake system downstream of the compressor while the second EGR valve is closed, and the second EGR valve being operable, when the direction control valve is selecting the second inlet, to control flow of recirculated exhaust gas to a location in the intake system upstream of the compressor while the first EGR valve is closed.