Selected problems of hydraulic system with pressure multiplication. The relation between development of new vehicles fueled technologies and using of small size gas cylinder for nominal pressure 70 MPa and more has been mentioned. Control of experimental research requires proportional valves in the pressure multiplication system. Pressure multiplication cylinder needs an adequate seals and specially mounting of seals.

Issues of impellers design with rapid prototyping using. In the paper issues connected with a design process of hydrodynamic sub-assemblies with using of rapid prototyping for fabrication of prototype impellers were presented. The aim of prototype using in the design process was shown. Problems of choice of rapid prototyping method and machine, fabrication errors and strength of fabricated impellers were described. Finally, the method of rapid prototyping for impellers fabrication was indicated.

Hydraulic damper with valve controlled by piezoelectric stack. The paper presents a semi-active hydraulic damper which utilizes experimental throttling valve for control of dampening force. A piezoelectric pile with an adequate extension range was applied for continuous adjustment of flow rate in the valve. Basic characteristics of piezoelectric materials and a description of laboratory tests of the damper with selected results are presented.

Directions of articulated vehicles steering system development. The paper analyzes the steering systems solutions of articulated machines applied by manufacturers. Advantages of arrangements with variable hydraulic gain have been pointed. The new demand for hydraulic steering system is cooperation with electronic and implementation of informatics systems.