Valve seat insert for long life natural gas lean burn engines

摘要

A valve seat insert of an engine has a valve seating surface including an outer curved segment forming a first wear crown for contacting the valve at an early wear state, an inner curved segment forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the outer and the inner curved segments. A top flow crown is set off radially inward from the engine head, and a sloping segment extending from the top flow crown is oriented at an acute angle relative to the valve seat center axis.