Patent ID: 8069905
Filing Date: 2011-12-06
Classification: F28D

Abstract:
1. An EGR gas cooling device comprising: an EGR gas pipe having an inlet, an outlet spaced downstream from the inlet along an axial direction and an outer peripherial wall extending from the inlet to the outlet, the outer peripheral wall being of substantially rectangular cross-section and including first and second opposed wall sections aligned substantially parallel to the axial direction, a multiplicity of flat cooling water pipes with two opposed flat wall sections aligned parallel to the axial direction of the EGR gas pipe joined by two opposed curved wall sections, the cooling water pipes perpendicularly intersecting an EGR gas flow direction in the EGR gas pipe and fixedly arranged in the EGR gas pipe to extend only in a single direction through the first and second wall sections of the outer peripheral wall of the EGR gas pipe with opposite inlet and outlet ends of the respective cooling water pipes opened to an outside of the EGR gas pipe at the respective first and second wall sections of the EGR gas pipe, all of the cooling water pipes being substantially straight, of equal lengths (L 2 )and parallel to one another, the EGR cooling device having no cooling water pipes aligned at an angle to the multiplicity of parallel cooling water pipes, a cooling jacket for engine cooling water, the cooling jacket being of substantially rectangular cross-section and being fixed to at least a part of an outer surface of the EGR gas pipe on both sides of a group of the cooling water pipes in the axial direction, and the EGR gas pipe is cooled by the cooling water flowing through the cooling water pipes, the group of cooling water pipes being disposed along a section of the EGR gas pipe having a length (L 1 ) in the axial direction that exceeds the length (L 2 ) of each of the cooling water pipes; the cooling jacket having opposite inflow and outflow walls aligned substantially parallel to the cooling water pipes, an inflow port extending into the cooling jacket at the inflow wall and an outflow port extending out of the cooling jacket at the outflow wall, a first separator extending from the inflow wall of the cooling jacket to the EGR gas pipe at a position in proximity to the inflow port and between the inflow port and the second wall section of the EGR gas pipe for channeling the cooling water only to the inlet ends of the cooling water pipes at the first wall section of the EGR gas pipe and a second separator extending from the outflow wall of the cooling jacket to the EGR gas pipe at a position in proximity to the outflow port and between the outflow port and the first wall section of the EGR gas pipe for channeling the cooling water from the outlet ends of the cooling water pipes at the second wall sections of the EGR gas pipe to the outflow port, the inflow port having an inlet end spaced from the cooling jacket and the outflow port having an outlet end spaced from the cooling jacket, the inlet end of the inflow port being offset from the outlet end of the outflow port in a direction measured perpendicular to both the cooling water pipes and the axial direction of the EGR gas pipe by a distance (D 1 ) that is less than a length (D 2 ) of the EGR gas pipe from the inlet to the outlet thereof.