Patent ID: 7108054

Claim:
A heat exchanger for use in exhaust gas recirculation to cool exhaust gas, the heat exchanger comprising: a substantially rectangular cover plate having a widthwise dimension, a lengthwise dimension that exceeds the widthwise dimension and a plurality of openings that include a liquid inlet opening positioned proximate to an end of a lengthwise side of the cover plate and a liquid outlet opening positioned proximate to an opposing end of an opposing lengthwise side of the cover plate and an exhaust gas inlet opening positioned proximate to a widthwise side, of the cover plate and an exhaust gas outlet opening positioned proximate to an opposing widthwise side of the cover plate wherein the cross-sectional flow area of the exhaust gas inlet opening exceeds the cross-sectional flow area of the liquid inlet opening, wherein the cross-sectional flow area of the exhaust gas outlet opening exceeds the cross-sectional flow area of the liquid outlet opening; a substantially rectangular upper plate having a widthwise dimension, a lengthwise dimension that exceeds the widthwise dimension and a plurality of openings that include a liquid inlet opening positioned proximate to an end of a lengthwise side of the upper plate and a liquid outlet opening positioned proximate to an opposing end of an opposing lengthwise side of the upper plate and an exhaust gas inlet opening positioned proximate to a widthwise side, of the upper plate and an exhaust gas outlet opening positioned proximate to an opposing widthwise side of the upper plate, wherein the exhaust gas inlet opening forms a seal with the exhaust gas inlet opening of the cover plate and the exhaust gas outlet opening forms a seal with the exhaust gas outlet opening of the cover plate to prevent exhaust gas flow into a liquid flow space defined by and between the cover plate and the upper plate; a substantially rectangular lower plate having a widthwise dimension, a lengthwise dimension that exceeds the widthwise dimension and a plurality of openings that include a liquid inlet opening positioned proximate to an end of a lengthwise side of the lower plate and a liquid outlet opening positioned proximate to an opposing end of an opposing lengthwise side of the lower plate and an exhaust gas inlet opening positioned proximate to a widthwise side of the lower plate and an exhaust gas outlet opening positioned proximate to an opposing widthwise side of the lower plate wherein the liquid inlet opening forms a seal with the liquid inlet opening of the upper plate and the liquid outlet opening forms a seal with the liquid outlet opening of the upper plate to prevent liquid flow into an exhaust gas flow space defined by and between the upper plate and the lower plate; and a substantially rectangular bottom plate.