Two-stroke-cycle dual-piston internal combustion engine

Claim 1

In a two-stroke cycle internal combustion engine having a first cylinder formed with an exhaust port, a second cylinder, said cylinders having respective axes, a crank chamber communicating with said cylinders, means for admitting a fluid to said crank chamber, first and second pistons respectively received in said cylinders for simultaneous reciprocating axial movement, each piston axially dividing the associated cylinder into a first compartment open toward said crank chamber and a second compartment permanently communicating with the second compartment of the other cylinder, said first piston leading, and said second piston trailing during said reciprocating movement, a crank shaft connected to said pistons for rotation of said crank shaft in said crank chamber in a predetermined direction in response to said reciprocating movement, said crankshaft including a crank pin assuming an angular bottom dead center position when said pistons are nearest said crank chamber, first control means on said first piston for opening and closing said exhaust port during each reciprocating movement of said first piston, said exhaust port remaining open while said crank shaft moves through a first angle, means defining a transfer port, said transfer port when open connecting the first compartment of said first cylinder with the second compartment of said second cylinder for flow of fluid between the connected compartments, second control means on one of said pistons for opening and closing said transfer port during each reciprocating movement of said one piston, said transfer port remaining open while said crank shaft moves through a second angle, the improvement which comprises: (a) said second control means including means opening said transfer port after the opening of said exhaust port by said first control means, and closing said transfer port before the closing of said exhaust port by said first control means; (b) said one piston being said first piston; (c) a line bisecting said first angle also bisecting said second angle; (d) said line being offset from said bottom dead center position in a direction opposite to said predetermined direction; and (e) said transfer port having two orifices directed tangentially relative to the circumference of said second compartment of said second cylinder in a manner to impart rotary movement in opposite respective directions to two streams of fluid flowing from said orifices into said second cylinder.