ENGINE EXHAUST REACTOR AND METHOD OF MAKING

In preferred embodiments, exhaust reactors for internal combustion engines are formed as large volume manifolds having cast iron outer shells containing baffled sheet metal inner liners spacedly supported within their respective outer shells to provide an insulating air space between the walls of the inner liner and outer shell. Means for providing a flow of air through the insulating space may be provided with the preheated air being delivered through means, internal or external of the manifolds, to the incoming exhaust gas stream for mixture therewith to aid combustion of the exhaust products. Construction of such reactors includes the steps of fabricating a metal inner liner, forming a sand core along the outer surfaces of the liner exclusive of certain supporting portions, casting a metal outer shell around the sand core and sheet metal liner so as to provide a protecting and supporting housing, and removing the core sand from the insulating space, preferably by shaking it out through openings formed in the outer shell.