Valve seat insert for engine head having venturi flow crowns and seating surface profiled for limiting valve recession

A valve seat insert for an intake valve in an internal combustion engine having a cylinder, the valve seat insert comprising:

• an annular insert body defining a valve seat center axis extending between a first axial end surface structured for facing the cylinder in the internal combustion engine, and a second axial end surface;
• the annular insert body further having an inner peripheral surface defining a throat structured to fluidly connect the cylinder to an intake conduit in an engine head, an outer peripheral surface, and a valve seating surface for contacting the intake valve extending between the first axial end surface and the inner peripheral surface;
• the valve seating surface including, in profile, an outer curved segment forming a first wear crown for contacting the intake valve at an early wear state, an inner curved segment forming a second wear crown for contacting the intake valve at a later wear state, and a linear segment extending between the outer curved segment and the inner curved segment;
• the inner peripheral surface including, in profile, an upper curved segment forming an incoming flow crown, and a sloping segment extending between the upper curved segment and the inner curved segment;
• and
• the upper curved segment transitioning with the second axial end surface, and the sloping segment extending radially inward from the upper curved segment at a venturi angle, of about 10° or greater, relative to the valve seat center axis, such that the inner peripheral surface forms a venturi to accelerate an incoming flow of gases to the cylinder.

A valve seat insert for an intake valve in an internal combustion engine having a cylinder, the valve seat insert comprising:

• an annular insert body defining a valve seat center axis extending between a first axial end surface structured for facing the cylinder in the internal combustion engine, and a second axial end surface;
• the annular insert body further having an inner peripheral surface defining a throat structured to fluidly connect the cylinder to an intake conduit in an engine head, an outer peripheral surface, and a valve seating surface for contacting the intake valve extending between the first axial end surface and the inner peripheral surface;
• the valve seating surface forming a first wear crown for contacting the intake valve at an early wear state, a second wear crown that is radially inward and axially inward of the first wear crown, for contacting the intake valve at a later wear state, and a middle surface that is linear in profile and extends between the first wear crown and the second wear crown;
• the inner peripheral surface forming an incoming flow crown transitioning with the second axial end surface, and a venturi disposed between the incoming flow crown and the second wear crown and defining a venturi angle of about 10° or greater relative to the valve seat center axis.