A four-stroke rotary-piston engine with adjustable compression ratio and adjustable valve control times, with which an efficient fuel combustion and the minimization of harmful exhaust gases are achieved while effective power is maximized, and which is suitable for the combustion of all fuels, comprising: an outer disk, an inner disk, at least one cylinder, at least one piston, at least one piston rod, characterized in that the engine comprises a pot-shaped round housing on which outer edge a fixed ring is arranged, the ring having sections, which are re adjustable by means of a step motor and a readjustment screw for adjusting the valve opening time, and which are provided with a recess, wherein the recess is for releasing a blockage that prevents free rotation, the outer disk and the inner disk are concentrically pivot-able, with the outer disk surrounding the inner disk, so that the disks (3, 7) are within the same plane, and wherein the inner disk can be rotated with respect to the outer disk by means of a compression control device to adjust compression, a fixed gear firmly mounted at the center of the housing, and a planet gear of the same size engaging therewith are arrangedbelow the disks (3, 7), the planet gear rotating a crank situated on its shaft, which passes through the inner disk upwards, the crank's length being equal to the gear radius, wherein the planet gear is rotatably mounted on the inner disk, wherein said crank, via the piston rod, reciprocates a lever having one end pivoted on the outer disk in such a way that it pushes the piston into and out of the cylinder affixed to the outer disk by means of a bar pivoted on the other end of the lever, and a rotary gate valve is located at the head of the cylinder, on which rotary gate valve a quarter valve rotation device is mounted, which rotates the rotary gate valve by one quarter revolution each time it hits the pin. an outer disk, an inner disk, at least one cylinder, at least one piston, at least one piston rod, the engine comprises a pot-shaped round housing on which outer edge a fixed ring is arranged, the ring having sections, which are re adjustable by means of a step motor and a readjustment screw for adjusting the valve opening time, and which are provided with a recess, wherein the recess is for releasing a blockage that prevents free rotation, the outer disk and the inner disk are concentrically pivot-able, with the outer disk surrounding the inner disk, so that the disks (3, 7) are within the same plane, and wherein the inner disk can be rotated with respect to the outer disk by means of a compression control device to adjust compression, a fixed gear firmly mounted at the center of the housing, and a planet gear of the same size engaging therewith are arrangedbelow the disks (3, 7), the planet gear rotating a crank situated on its shaft, which passes through the inner disk upwards, the crank's length being equal to the gear radius, wherein the planet gear is rotatably mounted on the inner disk, wherein said crank, via the piston rod, reciprocates a lever having one end pivoted on the outer disk in such a way that it pushes the piston into and out of the cylinder affixed to the outer disk by means of a bar pivoted on the other end of the lever, and a rotary gate valve is located at the head of the cylinder, on which rotary gate valve a quarter valve rotation device is mounted, which rotates the rotary gate valve by one quarter revolution each time it hits the pin.