High-Performance 48″ Chassis Dynamometer for Small-Pit Installation

The chassis dynamometer described in this paper incorporates the latest design improvements in instrumentation for certification applications. Unlike other large-roll chassis dynamometers, this machine fits into a pit that is only slightly larger than the dynamometer itself. All serviceable components are accessible from the top and there is no need, or reason, to require maintenance personnel to enter a pit. Advantages of the small pit approach are (1) improved safety, (2) enhanced access to serviceable components, (3) increased mechanical stability, and (4) lower installation cost. Other noteworthy design features in the dynamometer are (1) AC flux-vector power converter employing isolated gate bipolar transistors (IGBT's), (2) motorized trunnion mounting in which bearing hysteresis is eliminated and no warm-up is required, (3) lag-lead control algorithm, and (4) graphics oriented user interface.