Abstract: First intake valve and second intake valve for an engine cylinder bore within which a piston reciprocates are arranged side-by-side in a cylinder head for motion in unison along respective intake valve axes. First intake valve axis is nonparallel to the cylinder bore axis. A first intake valve seat for the first intake valve is disposed in a plane which is non-parallel to a plane which is perpendicular to the cylinder bore axis. First intake valve seat has a first semi-circumference toward a second semi-circumference of a second valve seat for second intake valve. At least a portion of first semi-circumference is closer, as measured along a direction parallel to the cylinder bore axis, to a plane passing through the piston perpendicular to the cylinder bore axis than is the second semi-circumference as measured along a direction parallel to the cylinder bore axis.

Abstract: An EGR cooler core has multiple tubes for conveying engine exhaust gas. Tube inlets are joined to a flat inlet header plate at tube/header plate joints in a flat zone of the inlet header plate. An endless groove in the inlet header plate circumscribes the joints while reducing a constant nominal thickness of the header plate in the flat zone along the groove without creating an opening through the header plate. This gives some compliance to the flat zone for mitigation of stresses induced by tube growth.

Abstract: First intake valve and second intake valve for an engine cylinder bore within which a piston reciprocates are arranged side-by-side in a cylinder head for motion in unison along respective intake valve axes. First intake valve axis is nonparallel to the cylinder bore axis. A first intake valve seat for the first intake valve is disposed in a plane which is non-parallel to a plane which is perpendicular to the cylinder bore axis. First intake valve seat has a first semi-circumference toward a second semi-circumference of a second valve seat for second intake valve. At least a portion of first semi-circumference is closer, as measured along a direction parallel to the cylinder bore axis, to a plane passing through the piston perpendicular to the cylinder bore axis than is the second semi-circumference as measured along a direction parallel to the cylinder bore axis.