Remanufactured engine piston and method

Patent metadata

Field	Value
Publication number	US-10926362-B2
Application number	US-201816219184-A
Country	US
Kind code	B2
Filing date	Dec 13, 2018
Priority date	Dec 13, 2018
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

A remanufactured piston for an internal combustion engine includes a crown and a skirt. A piston body includes a first piston body end within the crown and an opposite second piston body end. The crown further includes an annular crown body having an annular crown body edge. The first piston body end further includes an annular piston body edge. The annular piston body edge and the annular crown body edge form a joint, and a metallurgical bond attaches the annular crown body to the piston body at the joint.

First claim

What is claimed is:

1. A piston for an internal combustion engine, the piston comprising:
a piston body formed of a piston body material, and defining a longitudinal axis extending between a first piston body end and a second piston body end, the first piston body end including a combustion bowl, a piston body edge surface extending circumferentially around the longitudinal axis, and a lower backside surface,
the piston body edge surface extending from an upper combustion face at the first piston body end to an oil gallery of the piston;
the lower backside surface being disposed opposite the upper combustion face;

an annular crown body formed of a crown body material, and including a crown body edge surface extending circumferentially around the longitudinal axis, the crown body edge surface extending from the upper combustion face to the oil gallery, the crown body edge surface being positioned in facing relation to the piston body edge surface to form a joint; and
a metallurgical bond attaching the annular crown body to the piston body at the joint, and formed at least in part from the piston body material of the piston body and the crown body material of the annular crown body, the matallurgical bond extending from the upper combustion face to the lower backside surface,
wherein the combustion bowl includes a concave outer section and a backside cooling surface opposite the concave outer section, and the lower backside surface of the piston includes the backside cooling surface of the combustion bowl,
wherein the annular crown body includes an inside curved surface that transitions with the backside cooling surface to form the oil gallery, and
wherein the joint extends from the concave outer section of the combustion bowl to the oil gallery.

2. The piston of claim 1 wherein the piston is a remanufactured piston,
the piston body is a used piston body salvaged from a used piston removed from service in an internal combustion engine, and
the piston body edge surface is formed by cutting the used piston body.

3. The piston of claim 1 wherein the piston body material has a substantially identical material composition to the crown body material, and the metallurgical bond is an autogenous weld.

4. A method for making a piston for an internal combustion engine, the method comprising:
forming a piston body edge surface on a piston body that includes a combustion bowl having a concave outer section and a backside cooling surface opposite the concave outer section, the piston body edge surface extending from the concave outer section of the combustion bowl to an oil gallery of the piston, the piston body edge surface extending circumferentially about a longitudinal axis of the piston;
coupling the piston body with an annular crown body blank that includes a crown body edge surface structured to form a joint with the piston body edge surface such that the piston body edge surface and the crown body edge surface are positioned in facing relation, the crown body edge surface extending from the concave outer section of the combustion bowl to the oil gallery; and
bonding the annular crown body blank to the piston body by way of forming a metallurgical bond at the joint.

5. The method of claim 4 further comprising sorting a plurality of used pistons based on a crown piece damage criterion, and removing the piston from the plurality of used pistons based on the crown piece damage criterion.

6. The method of claim 5 wherein the crown piece damage criterion includes a ring groove damage criterion.

7. The method of claim 5 wherein the forming of the piston body edge surface includes removing a crown piece from the piston sorted from the plurality of used pistons.

8. The method of claim 7 wherein the forming of the piston body edge surface further includes cutting the piston sorted from the plurality of used pistons from the concave outer section of the combustion bowl to the oil gallery.

9. The method of claim 8 wherein the bonding of the annular crown body blank to the piston body further includes welding from the concave outer section of the combustion bowl to the oil gallery.

10. The method of claim 9 wherein the welding from the concave outer section to the oil gallery includes welding from the concave outer section to the backside cooling surface.

11. A crown assembly for a piston, the crown assembly comprising:
a piston body end of a piston body formed of a piston body material, the piston body end including an annular piston body edge surface and a combustion bowl having a concave outer section and a backside cooling surface opposite the concave outer section, the annular piston body edge surface extending from the concave outer section of the combustion bowl to an oil gallery of the piston, the annular piston body edge surface extending circumferentially about a longitudinal axis of the piston; and
a crown body blank formed of a crown body material, and including an upper surface forming an annular rim, an outside surface, an inside surface opposite the outside surface, and an annular crown body edge surface, the annular crown body edge surface extending from the concave outer section of the combustion bowl to the oil gallery, the annular crown body edge surface being positioned in facing relation with the annular piston body edge surface to form a joint.

12. The crown assembly of claim 11 further including a metallurgical bond attaching the crown body blank to the piston body end, and formed at least in part from the piston body material of the piston body end and the crown body material of the crown body blank.

13. The crown assembly of claim 11 wherein the crown body blank further includes an annular lip adjacent to the annular rim, the annular lip forming a step at an annular rim of the piston body that extends circumferentially around the combustion bowl.

Assignees

• Caterpillar Inc

Inventors

• Luick Kegan Jon
• Williams Kevin Byron
• Chu Nguyenbao Huynh
• Kinney Christopher Anthony

Classifications

• F02F3/22

  the fluid being liquid · CPC title

• F02F3/003 Primary

  the parts being connected by casting, brazing, welding or clamping · CPC title

• F02F2003/0061

  by welding · CPC title

• B23P6/02 Primary

  Pistons or cylinders · CPC title

• B23P15/10

  pistons · CPC title