The multi-cylinder hydropump, powered by internal combustion, has hydraulic pistons linked directly and axially to the pistons of the internal combustion cylinders, with separate couplings to give a sine shaped movement run. The hydraulic pistons (3) have a number of working surfaces (A) which are selected to alter or control the stroke volume or the pumped flow stream of the hydropump. The use of the added working surfaces (A) and intermediate zones are compensated by matching the piston frequency. The working surfaces (A) of the hydraulic pistons give a three-stage control function using AI or AII or AI+AII.
