What is a valve seat?

Valve Seat/Cylinder block/Piston/TOP ring/2ND ring/OIL ring/Cylinder Liner Figure 1: Internal combustion engine cylinder section

Valve cotter/Spring retainer/Valve spring/Spring seat/Valve Guide/Valve/Valve Seat Figure 2: Valve installed condition

In simple terms, the Valve Seat is the seat for the air intake valve and air exhaust valve. It is the part that makes contact with the valve, and maintains the airtightness of the combustion chamber.

Valve retention/airtightness retention

Function 1 Airtightness retention

Board/Head/Valve/This part maintains airtightness (seat part)/Combustion gas pressure/Valve Seat

Tightly holds when the valve is seated, prevents compressed gas or combustion gas leaking into the manifold from between the valve and Valve Seat.

Function 2 Heat conduction

Heating/High temperature combustion gas/Releases heat from valve

Reduces vale and cylinder head friction at the same time.

Required features

Manufacturing process (sintering manufacture method)/Dust mixture (combined material design possible)/Dust forming (near net shape)/Sintering/Processing (minimum required process)

Furthermore, the following are required features of Valve Seats

It should not be aggressive toward its valve
It should be a reasonable cost. →Reduced processing through sintering manufacture method.
Easy to machine for processing at the customer.

The above features can be given as functions in combination to a single product through a manufacture method called sintering (see figure).