Patent ID: 7124812

Claim:
An exhaust gas recirculation system with a heat exchanger for an internal combustion engine comprising: an exhaust conduit for containing flowing heated exhaust in fluidic contact with the exhaust manifold of an internal combustion engine and the intake manifold of the internal combustion engine; a recirculating liquid coolant conduit; and a heat exchanger disposed alone the exhaust conduit, the heat exchanger comprising: at least one exhaust plenum for containing flowing heated exhaust having at least one inlet receiving flowing heated exhaust and at least one outlet for discharging flowing heated exhaust, said inlet(s) spaced from said outlet(s); and at least one elongated coolant plenum for containing flowing liquid coolant, the coolant plenum contacting the exhaust plenum and having at least one first zone adjacent to the at least one inlet of the exhaust plenum and at least one second zone adjacent to the at least one outlet of the exhaust plenum, wherein the number of coolant plenum(s) is the same in the first zone and the second zone, the first zone comprising an area-in-flow less than an area-in-flow of the second zone, whereby the liquid coolant has a higher velocity in the second zone than in the first zone.