Valve seat insert for long life natural gas lean burn engines

A valve seat insert for an intake valve in an internal combustion engine 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 an 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 a top 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 an acute angle, of about 5° 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 exhaust valve in an internal combustion engine 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 exhaust conduit in an engine head, an outer peripheral surface, and a valve seating surface for contacting an exhaust 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 exhaust valve at an early wear state, an inner curved segment forming a second wear crown for contacting the exhaust 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 a top 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 an acute angle, of about 9° or greater, relative to the valve seat center axis, such that the inner peripheral surface forms a diffuser to decelerate an outgoing flow of gases from the cylinder.