Engine head assembly with valve seat insert with stiffness relief cutout
AssigneeCaterpillar Inc.
InventorsJeffrey Clark Krieger, Michael Dean Roley
Life of this patent
Estimating the term…
Abstract
An engine head assembly includes a valve seat insert having a valve seating surface defining a center axis, and each of an inner peripheral surface and an outer peripheral surface extending circumferentially around the valve seat center axis. The outer peripheral surface includes an upper section interference-fitted with the engine head, and a lower section. A stiffness relief channel is formed by a relief cutout in the valve seat insert, and extends radially between the lower section of the outer peripheral surface and the engine head. The stiffness relief channel permits flexing of the valve seat insert to cushion valve seating to prolong engine valve and valve seat insert service life.
Claims18
An engine head assembly comprising:
- an engine head including a fireside surface structured to face a cylinder in an engine, and the engine head having formed therein a valve seat bore, and a gas exchange conduit connecting to the valve seat bore;
- a valve seat insert including a valve seating surface defining a center axis, a first axial end abutting the engine head within the valve seat bore, and a second axial end;
- a gas exchange valve including a valve head, and being movable between a closed valve position where the valve head contacts the valve seating surface, and an open valve position;
- the valve seat insert further including an inner peripheral surface extending circumferentially around the valve seat center axis and forming a throat, for communicating gases between the gas exchange conduit and the cylinder, and an outer peripheral surface;
- the outer peripheral surface including an upper section adjacent to the first axial end and interference-fitted with the engine head within the valve seat bore, and a lower section extending between the upper section and the second axial end;
- and
- a stiffness relief channel extends radially between the lower section of the outer peripheral surface and the engine head, the stiffness relief channel being circumferential of the valve seat insert and opening in a direction of the fireside surface, and
- the stiffness relief channel is continuous from the upper section of the outer peripheral surface to the second axial end.
A valve seat insert for a gas exchange valve controlling gas exchange of a cylinder in an engine comprising:
- an annular insert body formed of a metallic material and including an inner peripheral surface, an outer peripheral surface, and a valve seating surface, the valve seating surface defining a center axis extending between a first axial end and a second axial end of the annular insert body;
- the inner peripheral surface extending circumferentially around the center axis and forming a throat, for communicating gases between a cylinder in the engine and a gas exchange conduit in an engine head in the engine;
- the outer peripheral surface extending circumferentially around the center axis, and including an upper section adjacent the first axial end, and a lower section extending between the upper section and the second axial end;
- the upper section having a full outer diameter dimension, and a cylindrical shape, for interference-fitting the annular insert body in a valve seat bore in the engine head;
- the lower section having a reduced outer diameter dimension, relative to the upper section, such that the outer peripheral surface is stepped radially inward from the upper section to the lower section, and forms a relief cutout for limiting a stiffness of the valve seat insert,
- the relief cutout having a radial width dimension and a first axial length dimension, and the upper section having a second axial length dimension;
- the first axial length dimension is greater than the radial width dimension and less than the second axial length dimension;
- and
- the relief cutout is continuous from the upper section of the outer peripheral surface to the second axial end.
A valve seat insert for a gas exchange valve controlling gas exchange of a cylinder in an engine comprising:
- an annular insert body formed of a metallic material and including an inner peripheral surface, an outer peripheral surface, and a valve seating surface, the valve seating surface defining a center axis extending between a first axial end and a second axial end of the annular insert body;
- the inner peripheral surface extending circumferentially around the center axis and forming a throat, for communicating gases between a cylinder in the engine and a gas exchange conduit in an engine head in the engine;
- the outer peripheral surface extending circumferentially around the center axis, and including an upper section adjacent the first axial end, and a lower section;
- the upper section having a full outer diameter dimension, and a cylindrical shape, for interference-fitting the annular insert body in a valve seat bore in the engine head;
- and
- the lower section having a reduced outer diameter dimension, relative to the upper section, and forming a relief cutout that is continuous from the upper section of the outer peripheral surface to the second axial end.
Dependencies are inferred from the claim text.