Abstract: In an internal combustion engine, two opposed pistons of equal radius are slidably mounted in a cylinder and respectively connected to cranks of unequal throws mounted for rotation at oppositely disposed cylinder ends in a common crankcase. The pistons are adjustable in opposing linear travel to define a flexible cylinder-head, the relative piston positions of piston proximity establishing a range of compressions therebetween correspondable to the respective compression-ignitions of a plurality of available fluid fuels. The cranks are gear connected and similarly offset from the cylinder's longitudinal centerline to eliminate dead centers, produce higher combustion pressures at more effective crank angles, and coordinate the pistons' relative linear speeds in exhaust, air intake, fuel injection, compression and power production in two cycle operation of the engine.

Abstract: In an internal combustion engine, two opposed pistons of equal radius are slidably mounted in a cylinder and respectively connected to cranks of unequal throws mounted for rotation at oppositely disposed cylinder ends in a common crankcase. The pistons are adjustable in opposing linear travel to define a flexible cylinder-head, the relative piston positions of piston proximity establishing a range of compressions therebetween correspondable to the respective compression-ignitions of a plurality of available fluid fuels. The cranks are gear connected and similarly offset from the cylinder's longitudinal centerline to eliminate dead centers, produce higher combustion pressures at more effective crank angles, and coordinate the pistons' relative linear speeds in exhaust, air intake, fuel injection, compression and power production in two cycle operation of the engine.