Claims
- 1. A single cylinder, four stroke cycle, overhead cam internal combustion engine comprising:
- an engine block including integrally formed cylinder and cylinder head and having a camshaft cavity and a crankcase cavity;
- an interconnected crankshaft, connecting rod and piston assembly disposed in said crankshaft cavity;
- an overhead camshaft and valve assembly disposed in said camshaft cavity;
- a pair of valve stem bores extending through said block between said camshaft cavity and said crankcase cavity, said valve assembly including valve stems disposed in said stem bores;
- said cylinder being substantially symmetric about the axis of the piston stroke; and
- a lubricant reservoir disposed externally of said engine block.
- 2. The engine of claim 1 wherein said camshaft includes a drive member located externally of said engine housing, wherein said crankshaft includes a drive member located externally of said engine block, and further including an endless loop member interconnecting said drive members for transmitting rotational motion from said crankshaft to said camshaft.
- 3. The engine of claim 1 wherein said crankcase cavity includes a cylinder bore in which said piston reciprocates, said cylinder bore defined by an annular wall of said block having a substantially uniform thickness around substantially all of the wall circumference in the area of said bore where said piston reciprocates.
- 4. The engine of claim 3 wherein said cylinder includes an annular wall segment along which the piston reciprocates, and said wall segment has a substantially uniform wall thickness around substantially all of the wall circumference.
- 5. The engine of claim 1 wherein said cylinder includes an annular wall segment along which the piston reciprocates, and said wall segment has a substantially uniform wall thickness around substantially all of the wall circumference.
- 6. The engine of claim 5 and including at least one cooling fin circumscribing said wall segment.
- 7. The internal combustion engine of claim 6 wherein said at least one cooling fin comprises a plurality of axially spaced, annular cooling fins.
- 8. The internal combustion engine of claim 1 wherein: said camshaft includes a camshaft sprocket located external of said engine block, said crankshaft includes a drive sprocket located external of said engine block, said engine comprises an endless loop drive member interconnecting said drive sprocket and said camshaft sprocket for transmitting rotational motion therebetween, and said drive member is located external of said engine block.
- 9. The engine of claim 8 and including at least one flywheel for providing rotational inertia disposed on said crankshaft at a location within said crankcase cavity.
- 10. The engine of claim 1 and including a fan connected to said crankshaft at a location external of said engine block, said fan rotatable with said crankshaft to produce a cooling air flow over said cylinder and head.
- 11. The engine of claim 1 wherein said crankshaft is vertically disposed.
- 12. The engine of claim 1 and including at least one flywheel for providing rotational inertia disposed on said crankshaft at a location within said crankcase cavity.
- 13. The engine of claim 12 wherein said flywheel is integral with said crankshaft.
- 14. The engine of claim 1 further comprising a dry sump lubrication system, said lubrication system including said lubricant reservoir, means including a pump for supplying lubricant from said reservoir to said crankshaft and means for returning lubricant used to lubricate said camshaft from within said engine block back to said external reservoir.
RELATED APPLICATIONS
This application is a divisional application of U.S. application Ser. No. 08/673,100, filed Jul. 1, 1996, now U.S. Pat. No. 5,755,194. This application claims benefit of provisional application 60/000,915 filed Jul. 6, 1995.
US Referenced Citations (73)
Foreign Referenced Citations (1)
Number |
Date |
Country |
63-147906 |
Jun 1988 |
JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
673100 |
Jul 1996 |
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