ADJUSTABLE FLOW-CONTROL VALVE FOR THE SELF-ENERGISING ELECTRO-HYDRAULIC BRAKE
Keywords:hydraulic brake, self-energising, brake torque control, leakage-free adjustable flow-control valve, flow-control valve, integrated valve
This paper presents the design and performance of an electrically adjustable flow control valve. It is designed specifically for the self-energising electro-hydraulic brake which requires small volume flows, a fail-safe open characteristic, a leakage tight closed position, simple control by just one solenoid, good dynamics, and repeatability. The valve concept is based on a conventional pressure compensator design usually found in flow-control valves. The measuring orifice used to sense the flow through the valve is typically constant. In the presented design it is made adjustable using a hydro-mechanical pilot servo mechanism. The pilot is actuated by a proportional solenoid. The paper explains static flow equations used to parameterise the design. Dynamic simulation is used to validate the design before manufacturing. Measurements of the prototype show a good match with the simulation. Measurements of the main characteristics of the valve are shown, specifically the dynamic response to a step input as well as the flow-signal tracking and load pressure disturbance rejection behaviour. The valve is also tested in its target application, the self-energising electro-hydraulic brake, where it proves its effectiveness in normalising the response time of the non-linear and the inherently unstable brake. As opposed to a non-linear or gain scheduling control, with the new valve the controller of the brake can be designed as a simple switching control. This is an advantage for the overall brake's safety evaluation and therefore helps to improve the prospects of using the self-energising brake in future applications such as rail vehicles.
Ewald, J., Liermann, M., Stammen, C. and Murrenhoff,
H. 2008. Application of Proportional Seat
Valves to a Self-energising Electro Hydraulic
Brake. In Proceedings of the Symposium on Power
Transmission and Motion Control, September 10-
2008, Bath, England.
Ewald, J. 2011. Selbstverstärkende Elektro-
Hydraulische Bremse (SEHB) für Schienenfahrzeuge.
Dissertation. RWTH Aachen University,
Shaker, Aachen, Germany.
Hommen, W. 1986. Hydraulikbremse für Fahrzeuge,
insbesondere Schienenfahrzeuge. European Patent
Kuehnlein, M., Ewald, J., Murrenhoff, H. and Liermann,
M. 2011. Non-linear Control and Observer
Design for the Self-energizing Electro-Hydraulic
Brake. In Proceedings of the 52nd National Conference
on Fluid Power, March 23-25 2011, Omnipress,
Madison, Wisconsin, USA.
Liermann, M. 2008. Self-energizing Electro-Hydraulic
Brake. Dissertation. RWTH Aachen University,
Shaker, Aachen, Germany.
Linden, D. 2007. Das All-In-One-Ventil. O+P Ölhydraulik
und Pneumatik 05/2007, pp. 261 - 263.
Murrenhoff, H. 2011. Grundlagen der Fluidtechnik –
Teil 1: Hydraulik. Lecture Notes, Shaker, Aachen,
N.N. BS EN 13452-1:2003. 2003. Railway Applications
– Braking – Mass transit brake systems. British
Railway Standard, British Standards Institution.
N.N. ISO 6403 (1992-02-01). 1992. Hydraulic fluid
power – Valves controlling flow and pressure –
Test methods. International Standard, International
Organization for Standardization.
N.N. Sterling Hydraulics. GS02 74. Product Data
gs02_70_71_74.pdf, visited on October 17, 2011.
Roth, H. 2010. Stromregelventil mit Proportional-
Drosselventil und nachgeschalteter Druckwaage.
Swiss Patent No. CH699508A1.
Schmidt, M. 2010. Dichtheit als Entwicklungsschwerpunkt
für Sitzventile hochdynamisch schaltender
Zylinderantriebe. Dissertation. RWTH Aachen
University, Shaker, Aachen, Germany.
Trudzinski, M. 1980. Experimentelle und analytische
Bestimmung des Betriebsverhaltens von direktwirkenden
und vorgesteuerten 2-Wege-Stromregelventilen.
Dissertation. TH Aachen