Between the cylinder head and combustion chamber of an internal combustion engine, an intermediate sealing ring. The compressor further includes an air injection system including at least one air injection passage through the casing and including an outlet segment that opens out in an inclined manner upstream from and directed towards a row of rotor blades into a set-back zone of the inside face of the casing. The control roller is mounted on an axle which in the region of a first edge of the belt is pivotably mounted and in the region of a second edge of the belt is connected and movably guided at the second end thereof using guiding and adjusting means. Then, the switching control section supplies power from a backup power source when it detects that the power source is shut-down.