Efficiency increasing device of a drive for a power and heat generator

The device (1) has an expander (4) e.g. piston expander, provided at an exhaust pipe (3) and coupled with a compressor (9) e.g. turbo compressor, by a shaft (10), where low pressure is generated in the exhaust pipe. A hot exhaust gas flow is transversely sucked from the exhaust pipe, the expander, a vacuum pipe (5), a heat exchanger (6), a compressor supply line (8) and the compressor by the low pressure. The hot exhaust gas flow is emitted into atmosphere or to a heat consumer through an outlet of the device. An independent claim is also included for a method for increasing efficiency of a drive of a current- and heat generator.