Insulation layer on steel pistons without gallery

Patent metadata

Field	Value
Publication number	US-10273902-B2
Application number	US-201715436966-A
Country	US
Kind code	B2
Filing date	Feb 20, 2017
Priority date	Feb 22, 2016
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

A galleryless steel piston designed to improve thermal efficiency, fuel consumption, and performance of an engine is provided. The piston includes a steel body portion and a thermal barrier layer applied to an upper combustion surface and/or a ring belt to reduce the amount of heat transferred from a combustion chamber to the body portion. The thermal barrier layer has a thermal conductivity which is lower than a thermal conductivity of the steel body portion. The thermal barrier layer typically includes a ceramic material, for example ceria, ceria stabilized zirconia, and/or a mixture of ceria stabilized zirconia and yttria stabilized zirconia in an amount of 90 to 100 wt. %, based on the total weight of the ceramic material. The thermal barrier layer can also have a gradient structure which gradually transitions from 100 wt. % of a metal bond material to 100 wt. % of the ceramic material.

First claim

What is claimed is:

1. A galleryless piston comprising:
a body portion formed of steel,
said body portion including an upper wall including an undercrown surface,
said undercrown surface being exposed when viewed from an underside of said piston,
said upper wall including an upper combustion surface opposite said undercrown surface,
a ring belt depending from said upper wall and extending circumferentially around a central longitudinal axis of said piston,
a pair of pin bosses depending from said upper wall, and
a pair of skirt panels depending from said ring belt and coupled to said pin bosses,
a thermal barrier layer applied to at least a portion of said upper combustion surface and/or at least a portion of said ring belt, said thermal barrier layer having a thermal conductivity which is lower than a thermal conductivity of said steel of said body portion,
wherein said thermal barrier layer includes a ceramic material, and said ceramic material of said thermal barrier layer includes ceria in an amount of 90 to 100 wt. %, based on the total weight of said ceramic material.

2. A galleryless piston according claim 1 , wherein said ceria of said ceramic material has a thermal expansion coefficient at 21° C. ranging from 10E-6 to 11E-6 and said steel of said body portion has a thermal expansion coefficient at 21° C. ranging from 11E-6 to 14E-6.

3. A galleryless piston according claim 1 , wherein said ceramic material has thermal conductivity of less than 1 W/m·K.

4. A galleryless piston according claim 1 , wherein said thermal barrier layer has a gradient structure.

5. A galleryless piston according claim 4 , wherein said thermal barrier layer includes a metal bond material applied to said upper combustion surface and/or said ring belt, and said thermal barrier layer gradually transitions from 100 wt. % of said metal bond material to 100 wt. % ceramic material based on the total weight of said thermal barrier layer, and an uppermost portion of said thermal barrier layer is formed entirely of said ceramic material.

6. A galleryless piston according claim 5 , wherein said metal bond material includes steel or a superalloy.

7. A galleryless piston according claim 5 , wherein said metal bond material consists of metal in an amount of 100 wt. % based on the total weight of said metal bond material, said ceramic material consists of said ceramic in an amount of 100 wt. % based on the total weight of said ceramic material, and said thermal barrier layer consist only of said metal bond material and said ceramic material.

8. A galleryless piston according claim 1 , wherein said thermal barrier layer has a thickness of less than 500 microns.

9. A galleryless piston according to claim 1 , wherein said body portion is formed of a single piece of said steel, a plurality of struts couple said skirt panels to said pin bosses, said body portion presents an inner undercrown region extending along said undercrown surface and surrounded by said skirt panels and said struts and said pin bosses, a pair of undercrown pockets extend along said undercrown surface, each undercrown pocket is surrounded by one of said pin bosses and one of said skirt panels and said struts coupling said one pin boss to said one skirt panel, and said body portion does not have a cooling gallery floor or other features bounding or partially bounding a cooling gallery along said undercrown surface.

10. A galleryless piston comprising:
a body portion formed of steel,
said body portion including an upper wall including an undercrown surface,
said undercrown surface being exposed when viewed from an underside of said piston,
said upper wall including an upper combustion surface opposite said undercrown surface,
a ring belt depending from said upper wall and extending circumferentially around a central longitudinal axis of said piston,
a pair of pin bosses depending from said upper wall,
a pair of skirt panels depending from said ring belt and coupled to said pin bosses,
a thermal barrier layer applied to at least a portion of said upper combustion surface and/or at least a portion of said ring belt, said thermal barrier layer having a thermal conductivity which is lower than a thermal conductivity of said steel of said body portion,
said thermal barrier layer includes a ceramic material, and
wherein said ceramic material of said thermal barrier layer includes ceria stabilized zirconia in an amount of 90 to 100 wt. %, based on the total weight of said ceramic material.

11. A galleryless piston comprising:
a body portion formed of steel,
said body portion including an upper wall including an undercrown surface,
said undercrown surface being exposed when viewed from an underside of said piston,
said upper wall including an upper combustion surface opposite said undercrown surface,
a ring belt depending from said upper wall and extending circumferentially around a central longitudinal axis of said piston,
a pair of pin bosses depending from said upper wall,
a pair of skirt panels depending from said ring belt and coupled to said pin bosses,
a thermal barrier layer applied to at least a portion of said upper combustion surface and/or at least a portion of said ring belt, said thermal barrier layer having a thermal conductivity which is lower than a thermal conductivity of said steel of said body portion,
said thermal barrier layer includes a ceramic material, and
wherein said ceramic material of said thermal barrier layer includes a mixture of ceria stabilized zirconia and yttria stabilized zirconia in an amount of 90 to 100 wt. %, based on the total weight of said ceramic material.

12. A galleryless piston comprising:
a body portion formed of steel,
said body portion including an upper wall including an undercrown surface,
said undercrown surface being exposed when viewed from an underside of said piston,
said upper wall including an upper combustion surface opposite said undercrown surface,
a ring belt depending from said upper wall and extending circumferentially around a central longitudinal axis of said piston,
a pair of pin bosses depending from said upper wall,
a pair of skirt panels depending from said ring belt and coupled to said pin bosses,
a thermal barrier layer applied to at least a portion of said upper combustion surface and/or at least a portion of said ring belt, said thermal barrier layer having a thermal conductivity which is lower than a thermal conductivity of said steel of said body portion, and
wherein said body portion is formed of a single piece of said steel,
said steel has a thermal expansion coefficient at 21° C. ranging from 11E-6 to 14E-6,
a plurality of struts couple said skirt panels to said pin bosses,
said body portion presents an inner undercrown region extending along said undercrown surface and surrounded by said skirt panels and said struts and said pin bosses,
a pair of undercrown pockets extend along said undercrown surface,
each undercrown pocket is surrounded by one of said pin bosses and one of said skirt panels and said struts coupling said one pin boss to said one skirt panel,
said body portion does not have a cooling gallery floor or other features bounding or partially bounding a cooling gallery along said undercrown surface,
said upper combustion surface includes an annular first portion formed as a substantially planar surface extending along an outer periphery of said upper wall and a second portion forming a combustion bowl,
said second portion of said upper combustion surface has a non-planar, concave, or undulating surface that depends from said first portion,
said ring belt includes an upper land and a plurality of ring

Assignees

• Fed Mogul Llc
• Tenneco Inc

Inventors

• Schneider Norbert G

Classifications

• C04B35/486

  Fine ceramics · CPC title

• F02F2003/0007

  Monolithic pistons; One piece constructions; Casting of pistons · CPC title

• F02F2200/06

  Casting · CPC title

• C23C4/12

  characterised by the method of spraying · CPC title

• C23C28/345

  with at least one oxide layer · CPC title