FIELD: mechanical engineering; free-piston internal combustion engines. SUBSTANCE: according to proposed method chemical energy of fuel-air mixture is converted into mechanical energy in piston engines by compressing fuel-air mixture and creating conditions for converting fuel chemical energy into heat with subsequent conversion of heat energy into mechanical energy. Fuel-air mixture with fuel content less than lower limit of fuel ignition is subjected to compression, and conditions for conversion of chemical energy of fuel into heat energy are provided by building compression ratio exceeding 25. Device realizing this method has free piston moving in cylindrical housing furnished with inlet and outlet valves and mechanism conveying energy to external load. Cylindrical housing is made movable for translational or rotary motion and is connected through unidirectional drives with two flywheels turning in opposite directions, being intercoupled and connected with external load by common transmission. Mass (or moment of inertia) of free piston made for translational or rotary motion is not less than 0.5 of mass (moment of inertia) of cylindrical housing. EFFECT: reduced content of harmful admixtures in exhaust gases, increased efficiency of utilization of fuel chemical energy. 3 cl, 2 dwg
