The article proves the necessity for heating the air in the pneumatic engine of a hybrid power unit designed for moving a compact wheeled vehicle. The aim is to improve the pneumatic engine operation indicators by heating the compressed air before it is supplied to the cylinder using the obtained theoretical and experimental studies. For the easy-to-use of assessing the effectiveness of heating the air supplied to a pneumatic engine, the experiments were carried out by two pressure ps = 0.7 MPa and
ps = 0.9 MPa, according to them the testing of a pneumatic unit was conducted without heating the compressed air at the temperature equal to the ambient temperature Ts = 293 K. Also, during the experiments a pneumatic engine was tested at other temperatures while supplying the compressed air at the inlet to the engine cylinder. So, at an inlet pressure ps = 0.7 MPa, the compressed air was heated up to the temperature Ts = 383 K, and at a pressure ps = 0.9 MPa it was heated up to the temperature Ts = 388 K. The conclusions reached regarding the efficiency of heating the air at the inlet to the pneumatic power unit cylinders were drawn for the case when the pneumatic engine is used as part of a vehicle hybrid power unit and the air is heated by using the heat of exhaust gases from an internal combustion engine operating simultaneously or a heat accumulator. The studies carried out in this article make it possible to determine the feasibility of the joint use of a pneumatic power unit and an internal combustion engine, not only in severe operating conditions with heavy traffic on busy road sections of large cities and megalopolises, but also during the independent operation of a pneumatic engine in traffic jams..