Quantification of energy losses in suspension dampers and itseffects on rolling resistance
article
The energy consumption of battery electric buses, and electric vehi-cles in general, depends to a large extent on rolling resistance.Although often aggregated into one, the energy lost due to rollingresistance can be subdivided into losses occurring in or at the tyreand losses occurring in the shock absorbers of the vehicle suspen-sion. In this paper, the energy dissipated by the dampers of a batteryelectric bus is quantified in an energy consumption context. The anal-ysis is based on a description of the vertical vehicle dynamics usinga quarter-car model with a nonlinear dashpot. The model is vali-dated by comparing suspension deflection with a measurement on aknown road surface. It is shown that 73% of the energy dissipated inthe dampers occurs at road frequencies between 3 and 12 Hz. Modelsimulations on different simulated ISO 8608 road surfaces reveal thatdamper losses are in the order of 100 W on smooth roads (classes Aand B), yet can reach values of several kW’s on rough roads (class D) at40 km/h. A comparison with rolling resistance coefficients obtainedfrom coast-down tests shows that the damper losses can explain themajority of the rolling resistance difference between road surfaceswith a different roughness.
Topics
TNO Identifier
1009281
Source
Vehicle System Dynamics
Publisher
Taylor & Francis