Abstract: A crankcase scavenged two cycle engine is provided with a supplemental variable volume chamber or plenum connected with the crankcase chamber for each cylinder to controllably vary the effective volume of the crankcase chambers and thereby control scavenging pressure. Control methods for providing more consistent scavenging and more efficient charge control are disclosed.

Abstract: A two-stroke cycle gasoline engine, comprising a power cylinder-piston assembly having a scavenging port configuration including a first scavenging port configuration first uncovered by the power piston as it moves along the power cylinder from its top dead center to its bottom dead center and a second scavenging port configuration uncovered by the power piston as it moves from its top dead center to its bottom dead center immediately after said power piston has completed uncovering the first scavenging port configuration, wherein the general rate relative to piston position in the power cylinder of uncovering of the area of the first scavenging port configuration is substantially lower than that of the second scavenging port configuration, so that the idling and low-load performance of the engine is substantially improved by improving scavenging.

Abstract: The invention relates to an improvement in a two-stroke internal combustion engine with opposed cylinders of different diameters which communicate by way of a combustion chamber of bell configuration for radially stratifying the rich mixture charge fed tangentially into the minor cylinder and the air charge fed into the major cylinder.

Abstract: A two stroke internal combustion engine with at least one dual piston, the cylinders of which are connected to each other by a combustion chamber on the cylinder head side. The engine can be charged on the crank chamber side with an air or air/fuel mixture by a turbo or supercharger. Both the leading and trailing pistons of the dual piston construction control the process of transfer of the air or air/fuel mixture through a transfer port from the crank chamber side of the cylinders to the combustion chamber side of the cylinder for the trailing piston as well as the exhaust process such that the exhaust process begins before the initiation of the transfer process. The engine can operate on either the Otto or Diesel cycles and use multiple fuels.

Abstract: In a two-stroke-cycle dual-piston engine in which a fuel mixture is compressed in the crank chamber by the reciprocating pistons, the compressed fluid flows from the crank chamber and a compartment of one cylinder open toward the crank chamber through a transfer port into a compartment of the other cylinder between the piston therein and the cylinder head, thereafter through a combustion chamber in the cylinder head into the communicating compartment of the first-mentioned cylinder, and the exhaust gases are ultimately discharged through an exhaust port, the transfer port and exhaust port being opened and closed by control devices on the pistons, the exhaust port and transfer port are both controlled by the piston in the first-mentioned cylinder in such a manner that the exhaust port is opened before the transfer port and closed after the transfer port.