Four-stroke internal combustion engine

Abstract

A four-stroke internal combustion engine (20) is provided. There is provided within an engine housing (28) an oil reservoir (126) and a valve chamber (156) which independently communicate with a crank chamber (124). A strategically placed divider (116) and passageway, located within the engine housing (28), appropriately direct lubricant within the engine housing (28) so that the internal cavity of the engine is lubricated during use in various operating attitudes, and so that the fluid flows to and is held in the proper chambers of the engine housing during storage. There is also provided a breather arrangement for an internal combustion engine (20) which includes a cam shaft (98) having a hollow passageway in communication with the crank chamber (124) and the air intake system of the engine. There is also provided an engine housing which can be utilized for engines having different horse power ratings. There is also provided a crankshaft bearing assembly (68, 70) which prevents damage to the bearing upon insertion of the crankshaft (80) into the crank chamber (124).

Description

[0001] This application is a divisional application of the invention application whose application number is 00803081.2, the application date is January 13, 2000, and the invention name is "four-stroke internal combustion engine". technical field [0002] The present invention relates generally to four-stroke internal combustion engines, and more particularly to use in trimmers, blowers, vacuum machines, chain saws, other hand-held power tools, snow blowers, generators, vegetation cutting equipment such as lawn mowers, or other outdoor power equipment A four-stroke internal combustion engine is used. Background technique [0003] Many hand-held power tools or other outdoor power equipment are powered by electric motors or two-stroke internal combustion engines. Electric motors are limited in their range of applications due to the need to obtain power from cables or from long-lived batteries. A conventional two-stroke internal combustion engine includes a lubricating unit in...

AI Technical Summary

Problems solved by technology

[0004] However, the previous general opinion was that four-stroke internal combustion engines should only be used in limited applications, such as lawn mowers, snow blowers, generators, or other portable products with wheels

It is often thought that these existing four-stroke internal combustion engines are cumbersome and need to be used in transportable power tools

Furthermore, because oil and fuel generally need to be stored separately so that the oil can be used for lubrication, conventional low-cost four-stroke internal combustion engines cannot be designed to be used in any position other than the traditional upright position, because if the internal combustion engine is Significantly tilted, the oil will clog the internal combustion engine

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