US4531502A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally insulated piston
Assignee: Osram Sylvania Inc
•
Filing: 1983-05-18
•
Granted: 1985-07-30
•
Expires: 2003-05-18
Abstract
Abstract A thermally insulated piston for an internal combustion engine comprises a cast piston with a top wall having an annular recess, a cast iron annular cap in the recess, and a low thermal conductivity honeycomb structure between the cap and the bottom of the recess. The honeycomb structure has a plurality of cells, each formed of (stainless steel) foil filled with insulating material and brazed to the cap and to the bottom of the recess. This structure is a thermal barrier to the flow of heat from the cap to the main body of the piston, has high strength in compression and facilitates the adibatic expansion of gasses in the cylinder of the engine, particularly a diesel engine.
Inventors
- 👤 Howard Mizuhara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:22
CPC Classifications
F; F02; F02F; F02F3/00; F02F3/10; F02F3/12; F02B; F02B3/00; F02B3/06; F05; F05C; F05C2201/00; F05C2201/04; F05C2201/0433; F05C2201/0448
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
73 words
A piston for use in an internal combustion engine having a combustion chamber and having a longitudinal axis, comprising a main body having a wall defining part of said combustion chamber, said wall having a central recess with a bottom and a cap in said recess and a heat barrier disposed between and secured to said cap and the bottom of said recess, said barrier comprising a honeycomb structure containing thermal insulating material.
Claim 2
Dependent Claim
73 words
A piston for use in an internal combustion engine having a combustion chamber and having a longitudinal axis, comprising a main body having a wall defining part of said combustion chamber, said wall having a central recess with a bottom and a cap in said recess and a heat barrier disposed between and secured to said cap and the bottom of said recess, said barrier comprising a honeycomb structure containing thermal insulating material.
Claim 3
Dependent Claim
18 words
The piston according to claim 1 in which the composition of said body and said cap is iron.
Claim 4
Dependent Claim
15 words
The piston according to claim 1 in which said insulating material comprises hollow graphite spheres.
Claim 5
Dependent Claim
13 words
The piston according to claim 1 in which said insulating material comprises silica.
Claim 6
Dependent Claim
26 words
The piston according to claim 1 in which said honeycomb structure comprises a plurality of separate contiguous tubular cells having axes parallel to said piston axis.
Claim 7
Dependent Claim
18 words
The piston according to claim 5 in which said cells are defined by foil having low thermal conductivity.
Claim 8
Dependent Claim
15 words
The piston according to claim 6 in which said foil is composed of stainless steel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-29 | 1989-01-28 | 1989-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-29 | 1993-01-28 | 1993-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-29 | 1997-01-28 | 1997-07-30 | $7700.00 | Window Closed / Lapsed |