US5065712A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Internal combustion engines
Assignee: Ricardo PLC
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Filing: 1990-12-05
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Granted: 1991-11-19
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Expires: 2010-12-05
Abstract
Abstract A two-stroke engine includes at least one cylinder, a piston reciprocable within the cylinder and a cylinder head which contains at least one exhaust port and at least two inlet ports which are controlled by respective poppet valves. The cylinder defines a combustion chamber of pent-roof form with which the inlet and exhaust ports communicate. The inlet ports are of directed type whereby, in use, the flow of air through them is generally away from the exhaust valve(s) and thus flows down the wall of the cylinder adjacent the inlet port. The axes of the inlet ducts converge in the direction of flow through them and the axis of each inlet defines angle of at least 20° with that of the other inlet duct when viewed in the direction of the cylinder axis.
Inventors
- 👤 Giles E. Hundleby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:02
CPC Classifications
F; F02; F02B; F02B25/00; F02B25/14; F02B25/145; F02F; F02F1/00; F02F1/24; F02F1/42; F02F1/4214; F02B75/00; F02B75/02; F02B2075/022; F02B2075/025; F02B2275/00; F02B2275/48; F02F2001/241; F02F2001/244; F02F2001/245; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
189 words
An internal combustion engine including at least one cylinder, said cylinder having a wall and an axis, a piston reciprocable within said cylinder and a cylinder head, said cylinder head containing at least one exhaust port, a respective poppet valve controlling said at least one exhaust port, at least two inlet ports, respective further poppet valves controlling said at least two inlet ports and inlet ducts having respective axes and connected to respective inlet ports, said cylinder and said cylinder head defining a combustion chamber with which said inlet and exhaust ports communicate, said inlet ports being of directed type whereby, in use, the flow of air through said inlet ports is generally away from said at least one exhaust port and thus flows down said wall of said cylinder adjacent said inlet ports, said axes of said inlet ducts being convergent in the direction of flow through them and said axis of each said inlet duct defining an angle of at least 20° with that of the adjacent one of the other of said at least two inlet ports, when viewed in the direction of said cylinder axis.
Claim 2
Dependent Claim
189 words
An internal combustion engine including at least one cylinder, said cylinder having a wall and an axis, a piston reciprocable within said cylinder and a cylinder head, said cylinder head containing at least one exhaust port, a respective poppet valve controlling said at least one exhaust port, at least two inlet ports, respective further poppet valves controlling said at least two inlet ports and inlet ducts having respective axes and connected to respective inlet ports, said cylinder and said cylinder head defining a combustion chamber with which said inlet and exhaust ports communicate, said inlet ports being of directed type whereby, in use, the flow of air through said inlet ports is generally away from said at least one exhaust port and thus flows down said wall of said cylinder adjacent said inlet ports, said axes of said inlet ducts being convergent in the direction of flow through them and said axis of each said inlet duct defining an angle of at least 20° with that of the adjacent one of the other of said at least two inlet ports, when viewed in the direction of said cylinder axis.
Claim 3
Dependent Claim
23 words
An engine as claimed in claim 1 wherein the angle defined by said axes of said inlet ducts is between 20° and 120°.
Claim 4
Dependent Claim
23 words
An engine as claimed in claim 2 wherein the angle defined by said axes of said inlet ducts is between 40° and 90°.
Claim 5
Dependent Claim
44 words
An engine as claimed in claim 1 wherein said axes of said inlet ducts intersect at a point 0.75 R to 2 R away from said cylinder axis, when viewed in the direction of said cylinder axis, R being the radius of said cylinder.
Claim 6
Dependent Claim
63 words
An engine as claimed in claim 1 wherein each said inlet duct is bent shortly upstream of the associated inlet port and includes a short portion coaxial with said associated inlet port downstream of the bend and a longer portion upstream of said bend, said long and short portions having respective axes which are oppositely inclined at acute angles to said cylinder axis.
Claim 7
Dependent Claim
30 words
An engine as claimed in claim 5 wherein said axes of said short and longer portions of said inlet ducts are inclined to one another by between 30° and 90°.
Claim 8
Dependent Claim
34 words
An engine as claimed in claim 1 wherein each poppet valve controlling one of said inlet ports includes an elongate stem, said stem being inclined to said cylinder axis by between 10° and 60°.
References Cited (Backward Citations)
GB1568302A
Cited
US4805569A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-18 | 1995-05-20 | 1995-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-18 | 1999-05-20 | 1999-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-18 | 2003-05-20 | 2003-11-19 | $7700.00 | Window Closed / Lapsed |