Nitrided Engine Valve with HVOF Coating
AssigneeCaterpillar Inc.
InventorsMark Veliz, Daniel Sordelet
Life of this patent
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Abstract
A valve for use in an internal combustion engine is disclosed. The valve includes a stem connected to a fillet disposed between the stem and a seat face. A thermal spray technique, such as a high velocity oxy fuel coating spray (HVOF) is applied to the seat face. A nitriding treatment that includes a nitrogen source, which may or may not contain carbon, and heat may be applied after the HVOF spray. The heat allows the nitrogen and/or carbon to penetrate the HVOF layer and the seat face to form a compound zone. The compound zone enhances the wear resistance of the surface during engine operation.
Claims20
A valve for use in an internal combustion engine, the valve comprising:
- a stem connected to a fillet;
- a seat face that connects to the stem by the fillet;
- and
- a wear resistant coating applied to the seat face, wherein the wear resistant coating includes a high velocity oxy fuel coating spray (HVOF) layer and a nitriding treatment that includes an application of heat, wherein the heat allows nitrogen to diffuse and bond with the HVOF layer and diffuse and bond with the seat face to form a compound zone on the HVOF layer.
An internal combustion engine, comprising:
- a cylinder engine block including at least one combustion chamber;
- at least one air intake leading into the least one combustion chamber and defining a port configured to receive a valve, wherein the valve comprises:
- a stem connected to a fillet;
- a seat face that connects to the stem by the fillet;
- and
- a wear resistant coating applied to the seat face, wherein the wear resistant coating includes a high velocity oxy fuel coating spray (HVOF) layer and a nitriding treatment that includes an application of heat, wherein the heat allows nitrogen to diffuse and bond with the HVOF layer and diffuse and bond with the seat face to form a compound zone on the HVOF layer.
A method of improving an engine valve, comprising the steps of:
- applying a high velocity oxy fuel coating spray (HVOF) layer to a seat face of the engine valve;
- applying a nitriding treatment that includes an application of heat;
- heating nitrogen to cause the nitrogen to diffuse and bond with the HVOF layer and diffuse and bond with the seat face to form a compound zone on the HVOF layer;
- and
- creating a wear resistant coating on the seat face of the engine valve with the HVOF layer and the nitriding treatment.
Dependencies are inferred from the claim text.