Increasingly stringent fuel economy standards are forcing automobile manufacturers to search for efficiency gains in every part of the drive train from engine to road surface. Safety mechanisms such as stability control and anti-lock braking are becoming more sophisticated. At the same time drivers are demanding higher performance from their vehicles. Hybrid transmissions and batteries are appearing in more vehicles. These issues are forcing the automobile manufacturers to require more from their test stands. The test stand must now simulate not just simple vehicle loads such as inertia and windage, but the test stand must also simulate driveline dynamic loads. In the past, dynamic loads could be simulated quite well using Service Load Replication (SLR*1). However, non-deterministic events such as the transmission shifting or application of torque vectoring from an on board computer made SLR unusable for the test. The only way to properly simulate driveline dynamic loads for non-deterministic events is to provide a wheel-tire-road model simulation in addition to vehicle simulation. The HORIBA wheel slip simulation implemented in the SPARC power train controller provides this wheel-tire-road model simulation.
*1: Service load replication is a frequency domain transfer function calculation with iterative convergence to a solution. SLR uses field collected, time history format data.