Chassis concept for an low-wear tire-road rolling contact

Nowadays, great demands are placed on a chassis regarding ride comfort, safety, and driving dynamics. Meeting these demands often requires counteracting measures, so that the final chassis setup can only be a compromise. The chassis development therefore takes place in a field of tension, which is being expanded by requirements concerning manufacturing and developing costs, manufacturability, installation space, variety, weight, durability, and quality. In comparison, emissions and fuel consumption are currently less important features.

In the research area „Chassis concept for an energy efficient, low-wear tire-road rolling contact“ funded by the German Federal Environmental Foundation (Deutsche Bundesstiftung Umwelt - DBU), a novel approach to detailed analysis of the dynamic phenomena in the tire contact patch was pursued. The approach considers the nonlinear interactions of the likewise nonlinear subsystems axle, tire, and tire-road contact. The methodology is meant to be used already during the basic design of a chassis system. In the research project, a significant reduction of frictional power in the tire-road contact was achieved for a simple driving maneuver. The frictional power was chosen as evaluation parameter to be independent of the wear behavior of different tread rubber materials.

Based on a experimentally validated, detailed simulation model of a production vehicle’s rear axle with production tyres, various parameter studies were carried out for straight line driving. The generally accepted model FTire was used as a tire model. The effect of initial toe and camber angles on the friction work was analyzed as well as the kinematic design of the wheel orientation changes during wheel travel. In addition, the distribution of the friction work over the tire cross section was compared and evaluated for different designs. An exemplary calculation of the amount of tire wear for different kinematic designs was conducted using a literature-based wear model. It could be shown the developed methodology can significantly contribute to the reduction of environmental pollution due to tire wear.