摘要 |
An exhaust manifold is constructed of material varying in thickness. Auxiliary cooling, such as from an air flow, to a portion of the exhaust manifold, permits making this portion thinner than a portion shielded from the auxiliary cooling. This lowers the heat capacity of the thinner material, allowing the exhaust manifold to heat rapidly to the activation temperature of a catalyst. Thus, the catalyst is capable of removing harmful elements from the exhaust gases of an internal combustion engine more quickly, thereby reducing pollution to the atmosphere. Furthermore, an exhaust manifold having this structure is lighter and requires less material than conventional exhaust manifolds, thereby making production easier and less costly.
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