Evaluating the Performance of Chassis Dynamometers with Electric Inertia Simulation

“Specifications for Electric Chassis Dynamometers, Attachment A” was issued by the USEPA in 1991. Although the primary purpose of the document was to serve as a Request for Proposal, it has subsequently been used as a general procedural manual to assess the road-simulation accuracy of electric chassis dynamometers. Significant strides have been made in the development of electric dynamometers since 1991. Procedures are needed to demonstrate that a chassis dynamometer is indeed capable of required accurate road simulation. Procedures for assessing dynamometer calibration, evaluating dynamometer response time, and measuring simulation error are reviewed. Novel methods are proposed for determining dynamometer torque measurement response and overall dynamometer system response to a simulated instantaneous change in vehicle thrust. This is offered to help dynamometer users evaluate the performance of their machines.