The present invention relates to a valve seat insert that is configured to be installed within the cylinder head of an engine.
A valve seat in an internal combustion gasoline or diesel engine is the surface of the cylinder head against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. Maintaining proper tolerances between the valve seat and valve is important over the life of the engine, in that if the valve seat becomes deformed, or is improperly positioned, oriented, or formed during manufacture, leakage of gaseous fluids will occur which will adversely affect the engine compression ratio and therefore the engine efficiency, performance (horsepower), exhaust emissions, and engine life.
A valve seat insert may include an annular body disposed about a central axis. The annular body may have a radially inward face that defines an orifice and a radially outward face that is opposite the radially inward face. Additionally, the annular body may have a top face, and a bottom face that is opposite the top face. The valve seat insert further includes a plurality of heat transfer protrusions that extend from the radially outward face of the annular body.
In one configuration, at least one of the plurality of heat transfer protrusions may be a wedge-shaped protrusion that is substantially aligned with the central axis. The wedge-shaped protrusion may include a first end and a second end, wherein the first end of the wedge-shaped protrusion may extend a greater distance away from the radially outward face than the second end of the wedge-shaped protrusion. The first end of the wedge-shaped protrusion may also be substantially aligned with the top face of the annular body.
The insert may be configured to be press-fit into the cylinder head of an engine, such that the plurality of heat transfer protrusions plastically deforms the cylinder head of the engine. Likewise, a cylinder head for an engine may include a cylinder head body that defines a plurality of valve openings, with each valve opening including a respective recess configured to receive a valve seat insert. The cylinder head may further include a valve seat insert, of the kind described above, disposed within each of the plurality of recesses.
The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
Referring to the drawings, wherein like reference numerals are used to identify like or identical components in the various views,
The cylinder head 10 may include a cylinder head body 14 that may define the structure of the cylinder head 10, including the respective valve openings 12. The cylinder head body 14 may be formed from a metal, such as cast aluminum, as is typical in the art. In addition to defining the respective valve openings 12, the cylinder head body 14 may further define an annular recess about each respective valve opening 12 that is configured to receive a valve seat insert 16. The valve seat insert 16 may be a precision-formed inlay that may selectively receive the valve head to seal the valve opening 12. The valve seat insert 16 may comprise a material that is harder than the cylinder head body 14, and may exhibit greater wear-resistant properties than the material of the cylinder head body 14. For example, the valve seat insert may be a metallic alloy comprising cobalt, nickel, iron, aluminum, boron, carbon, chromium, manganese, molybdenum, phosphorus, sulfur, silicon, and/or titanium.
As generally illustrated in
Referring again to
As illustrated in
Each heat transfer protrusion 40 may be configured to increase the surface area contact between the valve seat insert 16 and the cylinder head body 14 beyond that of a simple annular ring. The increased surface area may correspondingly increase the ability for heat to pass between the insert 16 and cylinder head body 14 (i.e., across the insert-body junction) in view of the press-fit interface. In many automotive applications, the cylinder head body 14 may be actively cooled, such as through water-cooling methods. By maximizing the ability to conduct heat out of the valve seat insert 16 and into the cooler cylinder head body 14, the wear-resistant properties of the insert 16 may be maximized, while any thermal deformation of the insert 16 may be minimized. In this manner, the life and performance of the valve seat insert, and the sealing properties of the overall cylinder head valve may be increased.
As further illustrated in
As further shown in
The valve seat insert 16 may further include a valve mating face 70 that may be disposed between the radially inward face 24 and the top face 30 of the annular body 20. The valve mating face 70 may be configured to receive a valve head in a manner that may seal the orifice 26. The valve mating face 70 may include one or more chamfers, such as generally illustrated in
While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not as limiting.