The invention relates to an active chamber type constant pressure continuous "cold" combustion type cryogenic engine-compressor unit, which works in particular with working compressed air and uses: a piston stroke control device and an active chamber with a cold chamber (29) which The atmosphere at the inlet (28) of the supply air compression device (28, 25, 26, 33) can be lowered to a very low temperature, which then compresses this working compressed air, which is still at low temperature, into the outer combustion chamber (19 ), the outer combustion chamber (19) is equipped with a constant pressure heating device (19A), and the working compressed air increases in volume in the heating device (19A), and then is transported quasi-isothermally to the active chamber ( 13), and then expand in the working cylinder (2) to do work again. The invention is applied to land vehicles, cars, buses, motorcycles, ships, airplanes, emergency power generation devices, household appliances, and stationary heat engines.