Patent ID: 7461641

Claim:
An EGR cooling system for cooling EGR of an engine, comprising: a plurality of EGR coolers configured to cool the EGR to a plurality of successively lower temperatures, including a first EGR cooler that cools the EGR to a first temperature by an engine coolant of an engine coolant loop, a second EGR cooler that cools the EGR to a second, lower, temperature by an auxiliary coolant of an auxiliary coolant loop, wherein at least one of the EGR coolers includes a finned EGR cooler that comprises a plurality of channels for dissipating heat in the EGR, the plurality of channels increasing heat transfer surface area while having sufficient fin spacing to avoid clogging; a water-to-air charge air cooler included in the auxiliary coolant loop; and a catalyst configured to remove particle matters and/or hydrocarbons from the EGR, the catalyst positioned upstream of at least one of the plurality of EGR coolers.