US 4,926,814 AGranted

Crankcase breather and lubrication oil system for an internal combustion engine

AssigneeTecumseh Products Company

InventorKevin G. Bonde

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Abstract

An internal combustion engine having a vertically oriented crankshaft and a horizontally oriented cylinder bore and including a plurality of lubrication sites to be pressure lubricated. A first upstanding wall extends upwardly from the top wall of the crankcase and circumscribes and defines a first chamber. A breather passage communicates crankcase gases from the crankcase into the first chamber. A drain passage communicates oil separated from the crankcase gases in the first chamber into the cylinder bore below the piston and is positioned along the cylinder bore so as to be periodically occluded by the piston during reciprocation thereof. A second upstanding wall extends upwardly from the top wall of the crankcase in spaced relationship to at least a portion of the first wall, and defined together with the first wall a second chamber therebetween. A first oil passage communicates oil from a lubricant pump to the second chamber, and a second oil passage communicates oil from the second chamber to at least one of the lubrication sites.

Claims16

Dependent claims

In an internal combustion engine including a crankcase having a generally horizontally oiented top wall, an oil sump, an oil pump, and a vertically oriented crankshaft rotatably journalled therein, a horizontally oriented cylinder bore communicating with and extending from the crankcase, a piston disposed for reciprocation within the cylinder bore and linked to the crankshaft, and a plurality of lubrication sites, the improvement comprising:

a first upstanding wall extending upwardly from the top wall of said crankcase, said first upstanding wall circumscribing and defining a first chamber;
breather passage means for communicating crankcase gases from said crankcase into said first chamber;
drain passage means for communicating oil separated from the crankcase gases in said first chamber into the cylinder bore below the piston, said drain passage means being positioned along the cylinder bore so as to be periodically occluded by the piston during reciprocation thereof;
a second upstanding wall extending upwardly from the top wall of said crankcase in spaced relationship to at least a portion of said first wall, said first and second walls defining therebetween a second chamber;
first oil passage means communicating oil from said lubricant pump to said second chamber;
and
second oil passage means communicating oil from said second chamber to at least one of the lubrication sites.

4 more elements

Dependencies are inferred from the claim text.