US4840147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combustion chamber of a two-stroke engine
Assignee: Toyota Motor Corp
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Filing: 1988-07-05
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Granted: 1989-06-20
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Expires: 2008-07-05
Abstract
Abstract A two-stroke engine having an intake valve and an exhaust valve which are arranged on the cylinder head. A masking wall is formed on the inner wall of the cylinder head to mask the valve opening between the valve seat and the peripheral portion of the intake valve, which is located on the exhaust valve side, for the entire time for which the intake valve is open.
Inventors
- 👤 Toshio Tanahashi
- 👤 Norihiko Nakamura
- 👤 Hiroshi Noguchi
- 👤 Kenichi Nomura
- 👤 Toyokazu Baika
- 👤 Masanobu Kanamaru
- 👤 Tatsuo Kobayashi
- 👤 Hideo Nagaosa
- 👤 Kazuhiro Ito
- 👤 Toshio Ito
- 👤 Kouichi Nakae
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:15
CPC Classifications
F; F02; F02F; F02F1/00; F02F1/24; F02F1/42; F02F1/4214; F02B; F02B25/00; F02B25/14; F02B25/145; F02B1/00; F02B1/02; F02B1/04; F02B75/00; F02B75/02; F02B2075/022; F02B2075/025; F02B3/00; F02B3/06; F02F2001/244; F02F2001/245; F02F2001/247
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
118 words
A two-stroke engine comprising: an engine body including a cylinder head having an inner wall; a piston reciprocally movable in said engine body, the inner wall of said cylinder head and a top face of said piston defining a combustion chamber therebetween; at least one intake valve arranged on the inner wall of said cylinder head; at least one exhaust valve arranged on the inner wall of said cylinder head; masking means arranged between said intake valve and said exhaust valve to mask a valve opening formed between a valve seat and a peripheral portion of said intake valve, which is located on said exhaust valve side, for the entire time for which said intake valves is open.
Claim 2
Dependent Claim
118 words
A two-stroke engine comprising: an engine body including a cylinder head having an inner wall; a piston reciprocally movable in said engine body, the inner wall of said cylinder head and a top face of said piston defining a combustion chamber therebetween; at least one intake valve arranged on the inner wall of said cylinder head; at least one exhaust valve arranged on the inner wall of said cylinder head; masking means arranged between said intake valve and said exhaust valve to mask a valve opening formed between a valve seat and a peripheral portion of said intake valve, which is located on said exhaust valve side, for the entire time for which said intake valves is open.
Claim 3
Dependent Claim
57 words
A two-stroke engine according to claim 1, wherein said masking means has a masking wall arranged close to peripheral portion of said intake valve, which is located on said exhaust valve side, and extending downward toward said piston to a position lower than said intake valve when said intake valve is in the maximum lift position thereof.
Claim 4
Dependent Claim
23 words
A two-stroke engine according to claim 2, wherein said masking wall extends in an arc along the peripheral portion of said intake valve.
Claim 5
Dependent Claim
23 words
A two-stroke engine according to claim 3, wherein said masking wall extends along approximately one-third of the peripheral portion of said intake valve.
Claim 6
Dependent Claim
53 words
A two-stroke engine according to claim 2, wherein the inner wall of said cylinder head has a raised portion projecting downward therefrom toward said piston and extending between said intake valve and said exhaust valve along the inner wall of said cylinder head, and said masking wall is formed on said raised portion.
Claim 7
Dependent Claim
16 words
A two-stroke engine according to claim 5, wherein said raised portion has an approximately triangular cross-section.
Claim 8
Dependent Claim
17 words
A two-stroke engine according to claim 5, wherein said exhaust valve is spaced from said raised portion.
Claim 9
Dependent Claim
27 words
A two-stroke engine according to claim 5, wherein said raised portion extends along the entire length of the diameter of the inner wall of said cylinder head.
Claim 10
Dependent Claim
26 words
A two-stroke engine according to claim 8, wherein said engine is provided with two intake valves and said masking wall is provided for each intake valve.
Claim 11
Dependent Claim
30 words
A two-stroke engine according to claim 8, further comprising a spark plug arranged on the inner wall of said cylinder head on said intake valve side of said raised portion.
Claim 12
Dependent Claim
46 words
A two-stroke engine according to claim 10, wherein said raised portion has an arced central portion facing toward said exhaust valve, and said spark plug is arranged substantially at a center of the inner wall of said cylinder head and surrounded by said central arced portion.
Claim 13
Dependent Claim
85 words
A two-stroke engine according to claim 2, wherein said inner wall of said cylinder head has a depression formed thereon and comprises a substantially flat inner wall portion other than said depression, a bottom wall of said depression, and a circumferential wall of said depression, which is located between said inner wall portion and said bottom wall, said intake valve being arranged on said bottom wall, said exhaust valve being arranged on said inner wall portion, said masking wall being formed on said circumferential wall.
Claim 14
Dependent Claim
53 words
A two-stroke engine according to claim 12, wherein the circumferential wall of said depression extends between opposed ends of a circumferential wall of the inner wall of said cylinder head, and a portion of said circumferential wall other than said masking wall forms a fresh air guide wall extending downward toward said piston.
Claim 15
Dependent Claim
53 words
A two-stroke engine according to claim 13, wherein said engine is provided with two intake valves and said fresh air guide wall comprises a first guide wall located between said intake valves and second guide walls located between the circumferential wall of the inner wall of said cylinder head and said intake valves.
Claim 16
Dependent Claim
36 words
A two-stroke engine according to claim 14, wherein said first guide wall and said second guide walls are located in substantially same plane which extends substantially in parallel to a line passing through said intake valves.
Claim 17
Dependent Claim
30 words
A two-stroke engine according to claim 12, further comprising a spark plug arranged on said inner wall portion approximately at a center of the inner wall of said cylinder head.
Claim 18
Dependent Claim
24 words
A two-stroke engine according to claim 1, wherein said exhaust valve opens earlier than said intake valve and closes earlier than said intake valve.
Claim 19
Dependent Claim
26 words
A two-stroke engine according to claim 1, wherein said cylinder head has an intake port formed therein and a fuel injector arranged in said intake port.
Claim 20
Dependent Claim
42 words
A two-stroke engine according to claim 18, wherein fuel is injected from said fuel injector toward a portion of a rear face of a valve body of said intake valve, which portion is located on the opposite side of said masking means.
Claim 21
Dependent Claim
19 words
A two-stroke engine according to claim 19, wherein said fuel has a bar-like shape having a small spread angle.
Claim 22
Dependent Claim
28 words
A two-stroke engine according to claim 18, wherein fuel is injected from said fuel injector after said intake valve opens and before said piston reaches bottom dead center.
Claim 23
Dependent Claim
21 words
A two-stroke engine according to claim 1, further comprising a fuel injector arranged on the inner wall of said cylinder head.
References Cited (Backward Citations)
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Cited
US4162662A
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US4291655A
Cited
US4732117A
Cited
US4781154A
Cited
US4732118A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |