Aluminum foam core piston with coaxial laser bonded aerogel/ceramic head

Patent metadata

Field	Value
Publication number	US-2019017465-A1
Application number	US-201715650291-A
Country	US
Kind code	A1
Filing date	Jul 14, 2017
Priority date	Jul 14, 2017
Publication date	Jan 17, 2019
Grant date	—

Abstract

An insulated composite piston head that includes three or more layers is formed and used in a combustion engine. The first layer is an aluminum or aluminum alloy foam core. The second layer is a metal layer that at least partially encapsulates the foam core; wherein the metal layer is selected to be aluminum or an aluminum alloy. The third layer is a layer of an insulating material located on at least one surface of the metal layer. The deposition of the insulating layer is accomplished via the use of a coaxial laser process.

First claim

What is claimed is:

1 . An insulated composite piston head for use in a combustion engine; the piston head comprising:
an aluminum or aluminum alloy foam core; a metal layer that at least partially encapsulates the foam core; the metal layer comprising aluminum or an aluminum alloy; and a layer of an insulating material located on at least one surface of the metal layer.

2 . The composite piston head according to claim 1 , wherein the insulating material is an aerogel, a ceramic material, or a mixture thereof.

3 . The composite piston head according to claim 2 , wherein the insulating material comprises an aerogel that is encapsulated by a ceramic or aluminum shell.

4 . The composite piston head according to claim 1 , wherein the metal layer has a thickness of about 4 mm or more.

5 . The composite piston head according to claim 1 , wherein the insulating material layer exhibits a thickness that is about 1 mm or less.

6 . The composite piston head according to claim 1 , wherein the foam core has a porosity that is between about 20% to about 50%.

7 . The composite piston head according to claim 1 , wherein the piston head further comprises a lubricious piston coating on at least a portion of the outer surface of the insulated composite piston head.

8 . The composite piston head according to claim 7 , wherein the lubricious piston coating is a silicone or polytetrafluoroethylene.

9 . A combustion engine that incorporates one or more insulated composite piston heads according to claim 1 .

10 . The combustion engine according to claim 9 , wherein the piston head defines a longitudinal axis and opposing first and second ends, and wherein the metal layer encapsulates the foam core at the first end, and wherein the layer of insulating material covers the metal layer at the first end.

11 . The combustion engine according to claim 10 , wherein the metal layer does not encapsulate the foam core at the second end.

12 . A method of forming an insulated composite piston head, the method comprising:
creating a preformed aluminum or aluminum alloy foam core; suspending the preformed foam core in a piston head mold; injecting or casting molten aluminum or an aluminum alloy into the mold through gates or traps to form a metallic layer that at least partially encapsulates the foam core, thereby, forming a molded piston head; removing the molded piston head from the mold; depositing an insulating material on at least one surface of the molded piston head; performing at least one machining operation on the molded piston head such that the molded piston head conforms to a predetermined specification for the insulated composite piston head; and optionally, applying a lubricious piston coating to at least a portion of the outer surface of the insulated composite piston head.

13 . The method according to claim 12 , wherein the insulating material is applied using a coaxial laser deposition process.

14 . The method according to claim 13 , wherein the coaxial laser deposition process comprises:
providing a high pressure gas source; placing a metal powder in a feeder container; placing the molded piston head into a closed chamber; allowing the high pressure gas to force the metal powder from the feeder through a spray nozzle onto a surface of the molded piston head in the closed chamber; using a coaxial laser to fuse the powder that is applied to the surface of the molded piston head; and removing excess powder from the closed chamber.

15 . The method according to claim 14 , wherein the coaxial laser deposition process further comprises rotating the molded piston head and indexing the coaxial laser and spray nozzle using a robotic arm and a pyrometer to control the temperature of the surface on the molded piston head.

16 . The method according to claim 14 , wherein the coaxial laser deposition process further comprises the use of a separator to isolate excess metal powder that is reused by mixing the excess metal powder with the metal powder in the feeder container.

17 . A combustion engine that incorporates one or more insulated composite piston heads formed according to the method of claim 12 .

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Ardisana Gregory
• Sui Lang
• Sherman Steven
• Thai Edward
• Yeo Isaac
• Hollis Michael
• Ziolek Scott

Classifications

• F02B77/11

  Thermal or acoustic insulation · CPC title

• F05C2201/021

  Aluminium · CPC title

• F02F3/12 Primary

  on piston heads · CPC title

• F02F3/0084 Primary

  the pistons being constructed from specific materials · CPC title

• F16J1/01

  characterised by the use of particular materials (F16J1/02 takes precedence) · CPC title