Patent US4953528A successfully refreshed from Google Patents.
US4953528A
Expired / Lapsed
US
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Direct injection-type diesel engines
Assignee: NGK Insulators Ltd
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Filing: 1989-10-05
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Granted: 1990-09-04
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Expires: 2009-10-05
Abstract
Abstract A direct injection-type diesel engine includes a piston head formed with a novel piston combustion chamber, with an inner wall surface composed essentially of ceramic material having a low thermal conductivity. The combustion chamber has a reduced opening diameter to enhance a squish air flow out of the clearance space between the piston and the cylinder head, and allows significant reduction of smoke, unburnt hydrocarbon and particulates in the exhaust gas, as well as minimization of thermal loss of the engine.
Inventors
- 👤 Hiroshi Oikawa
- 👤 Naohisa Nakashima
- 👤 Tadaaki Matsuhisa
- 👤 Tadao Ozawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:19
CPC Classifications
F; F02; F02B; F02B23/00; F02B23/02; F02B23/06; F02B23/0618; F02B23/0621; F02F; F02F3/00; F02B19/00; F02B19/16; F02B19/165; F02B23/0603; F02B23/0672; F02F3/0015; F02F3/003; F02F3/26; F02F7/00; F02F7/0085; F02F7/0087; F02B2023/0612; F02B2275/00; F02B2275/14; F02B2275/40; F02B3/00; F02B3/06; F02B77/00; F02B77/11; F02F1/00; F02F1/24; F02F2001/244; F02F2001/247; F02F2001/249; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
121 words
A direct fuel injection-type diesel engine comprising: a cylinder with a predetermined bore diameter; a cylinder head on said cylinder; a piston reciprocably arranged in said cylinder and having a piston head which is formed with a combustion chamber, said combustion chamber including an inner wall surface and an opening which is opposed to said cylinder head; as well as a fuel injection nozzle fixedly mounted in said cylinder head for directly injecting fuel into said combustion chamber; said combustion chamber having said opening with a diameter which is 55% or less of said cylinder bore diameter, and having a maximum diameter which is 128% or more of said opening diameter, said inner wall surface being composed essentially of ceramic material.
Claim 2
Dependent Claim
121 words
A direct fuel injection-type diesel engine comprising: a cylinder with a predetermined bore diameter; a cylinder head on said cylinder; a piston reciprocably arranged in said cylinder and having a piston head which is formed with a combustion chamber, said combustion chamber including an inner wall surface and an opening which is opposed to said cylinder head; as well as a fuel injection nozzle fixedly mounted in said cylinder head for directly injecting fuel into said combustion chamber; said combustion chamber having said opening with a diameter which is 55% or less of said cylinder bore diameter, and having a maximum diameter which is 128% or more of said opening diameter, said inner wall surface being composed essentially of ceramic material.
Claim 3
Dependent Claim
25 words
The diesel engine as claimed in claim 1, wherein said combustion chamber has said opening diameter of 45% or less of the cylinder bore diameter.
Claim 4
Dependent Claim
25 words
The diesel engine as claimed in claim 1, wherein said combustion chamber has said opening diameter of at least 25% of the cylinder bore diameter.
Claim 5
Dependent Claim
25 words
The diesel engine as claimed in claim 1, wherein said piston combustion chamber has said maximum diameter of 150% or more of its opening diameter.
Claim 6
Dependent Claim
48 words
The diesel engine as claimed in claim 1, wherein the wall of the combustion chamber in the piston head and its surrounding regions are composed essentially of at least one ceramic material selected from the group consisting of silicon nitride, partially stabilized zirconia, sialon, alumina and silicon carbide.
Claim 7
Dependent Claim
34 words
The diesel engine as claimed in claim 1, wherein the ceramic material of the combustion chamber wall has a heat conductivity of 0.08 cal/cm.s.°C. or less, under the normal operation temperature of the engine.
Claim 8
Dependent Claim
34 words
The diesel engine as claimed in claim 6, wherein the ceramic material of the combustion chamber wall has a heat conductivity of 0.05 cal/cm.s.°C. or less, under the normal operation temperature of the engine.
Claim 9
Dependent Claim
30 words
The diesel engine as claimed in claim 1, wherein the wall surface of the combustion chamber is composed of ceramic material with a heat conductivity of at least 0.02 cal/cm.s.°C.
Claim 10
Dependent Claim
56 words
The diesel engine as claimed in claim 8, wherein a heat insulating element formed of a material with a heat conductivity of 0.02 cal/cm.s.°C. or less is arranged at a location which is included in a heat transfer passage to a cooling system of the engine, but which is not directly exposed to the combustion gas.
Claim 11
Dependent Claim
34 words
The diesel engine as claimed in claim 9, wherein said heat insulating element is arranged within the cylinder head, between the cylinder head main body and the cylinder head plate below the main body.
Claim 12
Dependent Claim
22 words
The diesel engine as claimed in claim 9, wherein said heat insulating element is arranged within the piston, below the piston head.
Claim 13
Dependent Claim
51 words
The diesel engine as claimed in claim 1, wherein said inner surface of the piston combustion chamber has, in a region corresponding to its maximum diameter, a radius of curvature of at least 5% of the cylinder bore diameter, as seen in a plane including the center axis of the chamber.
Claim 14
Dependent Claim
51 words
The diesel engine as claimed in claim 12, wherein said inner surface of the piston combustion chamber has, in a region corresponding to its maximum diameter, a radius of curvature of at least 7% of the cylinder bore diameter, as seen in said plane including the center axis of the chamber.
Claim 15
Dependent Claim
29 words
The diesel engine as claimed in claim 1, wherein said combustion chamber opening has upper and lower peripheral edges with a radius of curvature of 0.5 mm or less.
Claim 16
Dependent Claim
29 words
The diesel engine as claimed in claim 14, wherein said combustion chamber opening has upper and lower peripheral edges with a radius of curvature of 0.3 mm or less.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |