Patent ID: 7243632

Claim:
A small four-stroke gasoline engine with oil mist lubrication comprising: an upper case body 3 and a lower case body 4 , a crankshaft assembly 1 , a piston assembly 8 , a cylinder head assembly 5 , a cylinder head cover 6 and a lubrication oil way of engine, and the lubrication oil way of engine includes a crankshaft chamber B, a camshaft chamber C, an upper rocker arm chamber D and a condensation chamber E, and the camshaft chamber C is connected to the upper rocker arm chamber D via a tappet cavity 13 , and the upper rocker arm chamber D communicates with the condensation chamber E, wherein an oil mist chamber A is formed by an upper case body 3 and a lower case body 4 on one side of the crankshaft chamber B, and the bottom of the oil mist chamber A communicates with the crankshaft chamber B, an oilsplash impeller 2 is fixed onto the crankshaft which extends into the oil mist chamber A, an oil way 12 is provided on the upper case body 3 which is in between the oil mist chamber A and the camshaft chamber C, an oil return way 15 is provided on a cylinder head assembly 5 , an oil return way 14 is provided on the upper case body 3 , and the upper interface of the oil return way 15 communicates with the upper rocker arm chamber D, and its lower interface is connected to the oil return way 14 , and the lower interface of the oil return way 14 communicates with the crankshaft chamber B.