Hydraulic axial piston unit and method for controlling of a hydraulic axial piston unit

A hydraulic axial piston unit comprising:

• a rotational group for driving or being driven by a driving shaft, and
• a tiltable displacement element for adjusting the displacement volume of the rotational group,
• wherein the rotational group comprises a rotatable cylinder block in which working pistons are mounted reciprocally moveable in cylinder bores for conveying hydraulic fluid from a kidney-shaped inlet port to a kidney-shaped outlet port located on a valve segment of the hydraulic axial piston unit, said hydraulic axial piston unit further comprising for the adjustment of the displacement volume:
• at least two control ports each located on the valve segment between the respective circumferential ends of the kidney-shaped inlet port and the kidney-shaped outlet port, which control ports can be brought sequentially in fluid connection with the cylinder bores when the cylinder block rotates;
• at least one hydraulic fluid injector connected fluidly to one control port, for injecting pressurized hydraulic fluid via one control port into the passing cylinder bores, and
• at least one control line connected to the other control port, for draining hydraulic fluid from the passing cylinder bores.