The standard steering system in the nineties was the conventional hydraulic power steering systems (HPS). Alternative by the conventional steering, the electrohydraulic systems (EHPS) have been developed, which have an improved efficiency. However, such systems are still operating with a constant flow rate and the overall efficiency is not sufficient and satisfying. Finally the introduction of electromechanical steering systems (EPS) is part of the newest development, justifying the desire for electronic controllability and lower energy consumption. In order to reduce the high power dissipations, a hydraulic System with constant pressure supply (CPS = constant pressure steering) can be taken into account. However, due to reasons of costs, the CPS has never been realised for a big number of vehicles. Looking forward on the development of electronically controlled steering systems for the use in steer-by-wire vehicles, the design of the CPS could be attractive to the manufacturers. In this paper such a system, for use in passenger cars and at the example of a BMW 318i, is introduced. Regarding the power consumption, it is compared to the conventional steering (HPS). Concerning the efficiency the constant pressure steering system seems preferable for alternative steering systems. Furthermore, the various possibilities of electronic control allow the implementation of additional functionalities, such as speed sensitive assistance or track control. Looking forward on the development of steer-by-wire systems, more functionalities get possible, for instance controlled interventions to the dynamics of the vehicle movement according to a stability program like ESP. Hence, the CPS could be an approach for such systems.
Efficiency analysis of hydraulic power steering systems
Leistungsanalyse von hydraulischen Fahrzeuglenkungen
2003
20 Seiten, 19 Bilder, 3 Tabellen, 7 Quellen
Aufsatz (Konferenz)
Englisch
Hydraulic power steering system, vehicle and steering method of hydraulic power steering system
Europäisches Patentamt | 2015
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