FKFS Events

2025 FKFS Conference on Vehicle Aerodynamics

and Thermal Management

15 - 16 October 2025 | Leinfelden-Echterdingen

Session: Thermal Test & Validation | | 15:00 - 15:30

Optimisation of Chassis Dynamometer Force Variability for Floor Anchor Restraint Systems

Luke Williams, JLR

To ensure sufficient axle load correlation can be achieved between Climatic Wind Tunnel (CWT) chassis dynamometer testing and track testing, coast match methodology such as that seen in SAE J2264 should be utilised to ensure any facility-imposed forces are negated. Such methodology introduces increased test preparation time to carry out a coast match test prior to starting CWT testing. With increased pressure to reduce financial and environmental impact of CWT testing, an investigation into the repeatability of CWT vehicle installations was conducted. The investigation aimed to understand if a coast match test was required for subsequent installations of a vehicle into a CWT having completed an initial coast match test. An experiment was conducted to evaluate potential influencing factors, including tyre type, tyre pressure, dynamometer position and loading applied through the vehicle restraints. Analysis concluded that tyre pressure and loading applied through vehicle restraints led to the highest variability in applied force to the vehicle axles. Implementation of control techniques through inclusion of strain gauges to vehicle restraints reduced variability of axle loading normalised by track road load from a range of 13.2% - 4.5% down to 5.6 % - 1.8 % across speeds of 0-100 kph. Leveraging an improvement in vehicle installation repeatability allowed a singular coast match test to be utilised for subsequent vehicle tests, reducing both financial and environmental impact of CWT testing.