Engine

Claim 1

A 4-cycle, internal combustion engine comprising a pair of cylinders, each cylinder being open at one end and provided, at peripherally spaced points remote from the other end of said cylinder, with an inlet port and an exhaust port in its side walls, a crankshaft arranged adjacent the open ends of said cylinders, a piston reciprocably received in each said cylinder and defining therewithin a variable-volume combustion chamber, means extending through the open end of each said cylinder and drivingly connecting the piston therein to said crankshaft, the last said means and said crankshaft being arranged so taht said pistons move simultaneously toward and away from the axis of said crankshaft, each said piston being movable in its associated cylinder past its said ports to close and open same during each revolution of said crankshaft, a crankcase for said crankshaft, means for admitting a gaseous mixture to said crankcase, means providing a passageway from said crankcase to the inlet port of each said cylinder, and valve means for opening and closing said passageways, said valve meeans being drivingly connected to and operated by said crankshaft, and said valve means being arranged alternately to open said passageways only on occasions when said pistons move toward the axis of said crankshaft, said crankcase being generally cylindrically shaped about the axis of said crankshaft, said crankshaft being formed to provide eccentric bearing portions on which said means for drivingly connecting said pistons to said crankshaft are journalled and, on opposite ends of said bearing portions, counter balance portions which are fully cylindrical and concentric with the axis of said crankshaft and of a diameter slightly smaller than the internal diameter of said crankcase, the combined axial length of said counter balance portions being generally equal to the axial length of said crankcase less the combined axial lengths of said bearing portions, thereby to reduce the volume of the gaseous mixture receiving space in the crankcase to increase the efficiency with which the piston movement pumps said gaseous mixture to said cylinders, said means for admitting a gaseous mixture to said crankcase including reed valve means arranged to open when the pressure in said crankcase drops below the pressure of the gaseous mixture source and to close when the pressure in said crankcase exceeds the pressure of said source, said first mentioned valve means including rotary valve means, said rotary valve means including one or more valve members extending parallel to the axis of said crankshaft and across each said passageway, each of said valve members being formed to close its associated passageway during a portion of each revolution and to open it during the rest of each revolution throughout the period when its associated inlet port is opened by its associated piston, means defining an auxiliary chamber in open communication with the exhaust port of each said cylinder, each said auxiliary chamber being provided with a port at a point remote from the point of communication of said auxiliary chamber with said exhaust port, butterfly valve means dominating said auxiliary chamber port, and means driven from said crankshaft for opening said butterfly valve means only on the occasions when its associated cylinder exhaust port is opened by the piston therein moving downwardly on its power stroke.