Internal-combustion engines – Multiple cylinder – Cylinders radiating
Reexamination Certificate
2001-02-15
2001-08-28
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Multiple cylinder
Cylinders radiating
Reexamination Certificate
active
06279519
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to truly-opposed piston engines, which have two opposed rows of cylinders, and both cylinders of each opposed pair of cylinders fire simultaneously.
2. Description of Prior Art
Piston engines for general aviation include horizontally opposed cylinder types. The present invention is an optimization of this general form. Prior examples of horizontally opposed internal combustion engines include U.S. Pat. No. 688,349 (Scott and Conney, 1901), U.S. Pat. No. 2,234,900 (Jones, 1941), U.S. Pat. No. 2,253,490 (Bakewell, 1941), U.S. Pat. 4,413,705 (Inaga, 1983). A present example of this general type of engine is the Lycoming turbo-charged 380 horsepower engine.
SUMMARY OF THE INVENTION
Aircraft engines require especially high reliability and long service life. They also need a high power-to-weight ratio, fuel efficiency, and a low frontal cross-section to minimize drag. They also must be practical to service routinely and overhaul periodically. The need for maintenance over a long service life is partly due to strict maintenance schedules prescribed by aviation regulators such as the U.S. Federal Aviation Administration. It is also due to the long life of an average aircraft, which is much longer than that of personal cars and trucks. Optimizing an engine for the above requirements is the goal of this aircraft engine design.
The objective of the invention is provision of a piston engine with evolutionary improvements over the prior technology in long-term reliability, serviceability, power to weight ratio, stability of combustion, and reduced manufacturing cost. The following features achieve these objectives:
1. Each cylinder is an individual part, and is a simple solid of rotation, having no ports or bolt holes.
2. The cylinders have air-cooling fins.
3. The cylinders are made of a single material such as iron for optimum reliability and longevity, as opposed to aluminum cylinders with a bore hardening treatment or steel sleeves.
4. The cylinder heads and crankcase are made of a second material, such as aluminum, for reduced weight.
5. Each cylinder head covers only two adjacent cylinders. This modularity enables partial engine disassembly for repair, and enables piston and cylinder reconditioning without a lift winch.
6. The cylinder heads are water-cooled.
7. The crankcase, cylinders, and cylinder heads are assembled with only one bolt per two cylinders, as later explained.
8. Each opposed pair of pistons is powered simultaneously, and is connected to the crankshaft
180
degrees apart for symmetric cranking force.
9
. The engine components and accessories are optimized spatially for overall accessibility. This includes providing one camshaft below the crankshaft, and the other camshaft above it, to reduce crowding.
No prior engine has this optimum combination of features.
REFERENCES:
patent: 688349 (1901-12-01), Scott et al.
patent: 727455 (1903-05-01), Rumpf
patent: 730345 (1903-06-01), Coburn
patent: 785229 (1905-03-01), Risbridger
patent: 1282824 (1918-10-01), Hartson
patent: 1428858 (1922-09-01), Porter
patent: 1486298 (1924-03-01), Powell
patent: 1764386 (1930-06-01), Brockway
patent: 2076892 (1937-04-01), Irgens
patent: 2234900 (1941-03-01), Jones
patent: 2253490 (1941-08-01), Bakewell
patent: 2290936 (1942-07-01), Bakewell
patent: 3194222 (1965-07-01), Brown
patent: 3274982 (1966-09-01), Noguchi
patent: 3456630 (1969-07-01), Karlan
patent: 4215660 (1980-08-01), Finley
patent: 4305349 (1981-12-01), Zimmerly
patent: 4413705 (1983-11-01), Inaga
patent: 5778834 (1998-07-01), Piccinini
patent: 6223704 (2001-05-01), Chatelain
patent: 6240887 (2001-06-01), Tosaka et al.
Nagel William S.
Reid Phillip L.
McMahon Marguerite
Stewart John V.
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