Experimentally, the four-quadrant operation in the force-path diagram, which is characteristic of an active suspension strut, has been successfully demonstrated with the aLFD. Long-term tests showed that the bellows can withstand the higher stresses caused by the employment of the active rolling piston. Thus, the concept of the active change in the supporting surface of the air spring by way of an adjustment of the rolling piston diameter is in principle suitable for use in a series-production vehicle. The reduction in the energy consumption of the active shock absorber system is a prerequisite for use in the vehicle. Therefore, in a concept study, a hydrostatic system with minimum energy consumption was designed using the TOR method developed in SFB 805. However, the theoretical and experimental investigation of the first prototype, as well as an estimation of the potential for innovation, showed that the use of the actuator and transmission concept used – hydraulic swivel motor with mechanical cam transmission – is not useful. The reason for this is the high weight, the required space and the low mechanical efficiency of the transmission of approximately 60%. For this reason, in consultation with the industrial partner, it was decided to re-conceptualize the aLFD what is being continued in subproject C4.
The ended subproject T2 has been able to lay the foundations for the design of the active change in the rolling piston diameter as well as to define the system requirements of the aLFD for successful integration into a standard vehicle. Thus, it forms a basis for the subproject C4, that can be based directly on the results of T2 in the third delivery period. The developed method for the reduction of energy consumption is used as application examples within the framework of the TOR course at the Chair of Fluid Systems.
|Prof. Dr.-Ing. Peter Pelz|