Reciprocating-piston-type internal combustion engine particularly for the operation of passenger automobiles

Claim 1

A reciprocating-piston-type internal combustion engine comprising: a cylinder head; a crankcase having an upper portion integrally casted with said cylinder head; a plurality of main bearings having first bearing surfaces, each of said main bearings including a bearing block having similar upper and lower portions; a crankshaft mounted within said main bearings and having second bearing surfaces; connecting rods supported on said second bearing surfaces of said crankshaft; said crankshaft having ducts through which lubricating oil is supplied to said second bearing surfaces for the connecting rods and additional ducts terminating at said first bearing surfaces of said main bearings and serving for the supply of lubricating oil to said first bearing surfaces; said crankshaft further having a cavity extending at least from one end to the other end of said main bearings and connected with said ducts leading to said second bearing surfaces for said connecting rods and to said first bearing surfaces of said main bearings; a stationary annular groove located in the vicinity of one of said first bearing surfaces of said main bearing at one end of said crankshaft and being supplied with lubricating oil; said crankshaft having a further duct permanently connecting said cavity of said crankshaft with said annular groove; said crankcase having a surface of attachment on its upper portion, said attachment surface terminating in the area of said second bearing surfaces above said crankshaft; and, said bearing blocks being flanged to said attachment surface.