ONE-PIECE PISTON FEATURING ADDITIVE MACHINING PRODUCED COMBUSTION BOWL RIM AND COOLING GALLERY

• US 20150247474A1
• Filed: 03/02/2015
• Published: 09/03/2015
• Est. Priority Date: 03/03/2014
• Status: Active Grant

• Current Assignee: Tenneco Incorporated (Apollo Global Management, Inc.)
• Original Assignee: Federal-Mogul Corporation (Apollo Global Management, Inc.)
• Inventors: Evers, Ross, Kenningley, Scott, Cromme, Wolfram
• Granted Patent: US 9,765,727 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B22F 10/22 Direct deposition of molten metal
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B23K 10/027 Welding for purposes other than joining, e.g. build-up welding
• CPC Class Codes: B23K 2101/003 Pistons
• CPC Class Codes: B23K 26/342 Build-up welding
• CPC Class Codes: B23K 9/044 Built-up welding on three-dimensional surfaces
• CPC Class Codes: B23P 15/10 pistons
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C23C 4/08 containing only metal elements C23C4/073 takes precedence
• CPC Class Codes: C23C 4/129 Flame spraying
• CPC Class Codes: F02F 2003/0007 Monolithic pistons; One piece constructions; Casting of pistons
• CPC Class Codes: F02F 3/003 the parts being connected by casting, brazing, welding or clamping
• CPC Class Codes: F02F 3/0084 the pistons being constructed from specific materials
• CPC Class Codes: F02F 3/22 the fluid being liquid
• CPC Class Codes: Y02P 10/25 Process efficiency
• CPC Class Codes: Y10T 29/49263 by coating or cladding

Abstract

A piston capable of withstanding high temperatures and extreme conditions of a combustion chamber of an internal combustion engine and manufactured with reduced costs is provided. The method of manufacturing the piston includes casting or forging the bulk of the piston as a single-piece with an open cooling gallery from an economical first material, such as steel, cast iron, or aluminum. The method further includes forming a portion of a combustion bowl surface, which is a small area of the piston directly exposed to the combustion chamber, from a second material by additive machining. The second material has a higher thermal conductivity and higher resistance to oxidation, erosion, and oil coking, compared to the first material. The additive machining process is efficient and creates little waste, which further reduces production costs.

Claims

1. A method for manufacturing a piston for use in an internal combustion engine, comprises the steps of:

forming a crown portion and a skirt portion from a first material; and

forming at least a portion of a combustion surface along the crown portion from a second material by an additive machining process.

2. The method of claim 1, wherein the additive machining process includes applying the second material to the first material by a plasma transfer arc.

3. The method of claim 1, wherein the additive machining process includes applying the second material to the first material by a high velocity oxygen fuel spray.

4. The method of claim 1, wherein the additive machining process includes applying the second material to the first material by laser cladding or selective laser sintering.

5. The method of claim 1, wherein the additive machining process includes applying the second material to the first material by arc welding or additive welding.

6. The method of claim 1 including melting the first material along an area of the crown portion after forming the crown portion;

and wherein the additive machining process includes melting the second material, and applying the melted second material to the melted first material.

7. The method of claim 6, wherein the additive machining process includes applying a plurality of layers of the melted second material to the melted first material.

8. The method of claim 1, wherein the second material has at least one of a higher thermal conductivity, higher erosion resistance, higher resistance to coking adhesion, higher strength, and a higher oxidation resistance than the first material.

9. The method of claim 8, wherein the second material is selected from stainless steel, a nickel-based alloy, and a nickel-chromium-based alloy;

and the first material is selected from steel, cast iron, a cast iron alloy, aluminum, and an aluminum alloy.

10. The method of claim 1, wherein the step of forming the crown portion and skirt portion includes forming the crown portion and skirt portion as a single piece by casting or forging.

11. The method of claim 10, wherein the casting or forging step includes forming the crown portion to include a combustion bowl extending outwardly from a center axis to an upper end, a cooling gallery base wall extending outwardly from a base of the combustion bowl, and an outer rib extending upwardly from the cooling gallery base wall to present an open cooling gallery surrounding the center axis;

and the casting or forging step includes forming the skirt portion to extend from the outer rib to a lower end and to surround the center axis.

12. The method of claim 10, wherein the additive machining process includes forming the combustion surface between the upper end of the combustion bowl and the outer rib to close the open cooling gallery.

13. The method of claim 12, wherein the step of forming the combustion surface from the second material by the additive machining process includes forming a rim of the combustion bowl on the upper end of the combustion bowl.

14. The method of claim 13, wherein the upper end of the combustion bowl is a rim of the combustion bowl formed from the first material.

15. The method of claim 1, wherein the crown portion formed from the first material and the combustion surface formed from the second material together form a closed cooling gallery.

16. The method of claim 1, wherein the step of forming the crown portion includes forming an outer rib spaced from a combustion bowl, and the step of forming the combustion surface includes disposing a core material between the outer rib and combustion bowl and applying the second material to the core material.

17. A method of manufacturing a piston for an internal combustion engine, comprising the steps of:

casting or forging a crown portion and a skirt portion as a single piece from a first material, the first material being selected from steel, cast iron, a cast iron alloy, aluminum, and an aluminum alloy;

the casting or forging step including forming the crown portion to include a combustion bowl extending outwardly from a center axis to an upper end, a cooling gallery base wall extending outwardly from a base of the combustion bowl, and an outer rib with ring grooves extending upwardly from the cooling gallery base wall to present an open cooling gallery surrounding the center axis;

the casting or forging step including forming the skirt portion from the first material to extend from the outer rib to a lower end and to surround the center axis, and forming the skirt portion to include a pair of pin bosses disposed opposite one another and each presenting a pin bore for receiving a wrist pin;

forming a combustion surface between the upper end of the combustion bowl and the outer rib to close the open cooling gallery, wherein the combustion surface is formed from a second material having at least one of a higher thermal conductivity, higher erosion resistance, higher resistance to coking adhesion, and a higher oxidation resistance than the first material, and the second material is selected from stainless steel, a nickel-based alloy, and a nickel-chromium-based alloy;

the step of forming the combustion bowl surface from the second material including an additive machining process, the additive machining processes including melting the first material along the upper end of the combustion bowl or along the outer rib, melting the second material, and depositing a plurality of layers of the melted second material on the melted first material; and

the additive machining process including at least one of plasma transfer arc, high velocity oxygen fuel spraying, laser cladding, laser sintering, arc welding, and additive welding.

18. A piston for an internal combustion engine, comprising:

a crown portion and a skirt portion formed from a first material;

a combustion surface disposed along the crown portion, wherein at least a portion of the combustion surface is formed from a second material by an additive machining process; and

a heat affected zone defined by a first edge along the first material and a second edge along the second material, wherein the first edge has a shape following the shape of the second edge.

19. The piston of claim 18, wherein a single piece of the first material forms the crown portion and the skirt portion;

and the second material has at least one of a higher thermal conductivity, higher erosion resistance, higher resistance to coking adhesion, and a higher oxidation resistance than the first material.

20. The piston of claim 18, wherein an underside of the combustion surface includes surface irregularities immediately following the additive machining process and prior to any subsequent machining;

and the second material of the combustion surface includes martensite and tempered martensite in a crystalline structure.