Thin-walled exhaust gas manifold casting

摘要

A thin-walled exhaust gas manifold casting structure for an internal combustion engine is disclosed. The manifold is comprised of nodular iron and has walls defining a plurality of inlet ducts interconnecting with a shallow elliptical outlet duct, the walls having a generally uniform thickness in the range of 0.12-0.15 inches. An integrally cast rib extends across at least a plurality of inlet ducts to reduce thermal flexing in service. The rib, subsequent to casting, is bored to define a hollow cylinder having ports communicating with most of the inlet ducts for carrying a secondary air supply. The inlet ducts are also arranged to achieve compactness in the overall envelope of the manifold by (a) restricting the dimension between the inlet duct openings and the outlet duct opening to less than the major axis of the elliptical outlet opening, (b) interconnecting the inlet ducts with the singular outlet duct along generally one side thereof, and (c) limiting the included angle between the plane containing the inlet openings and the plane containing the outlet opening to about 50 DEG .