Adding Transient Cycle Capabilities to an Existing Engine Test Bench

The focus of this paper is the adaptation of an existing direct current (DC) dynamometer to transient operation in order to facilitate at least preliminary transient tests carried on for low-budget engine development purposes. The original control software does not allow any dynamic testing. Therefore, new software for the test bench control was developed for the purposes of transient cycles testing. The software was applied on the test bench equipped with a DC dynamometer. The software is able to control the dynamometer, acceleration pedal and other additional functions like read and control ECU calibration software INCA, communicate with an acquisition system and other. The article describes a computation of the dynamometer inertial torque (torque is measured as a reaction of stator), creating and setting of a PID regulator for acceleration pedal control, mapping of the engine for the specific transient cycle and check of the results after the test according the emission standardization. Using this setup, a heavy duty diesel on-road engine has been tested on the European Transient Cycle (ETC) and the World Harmonized Transient Cycle (WHTC) and a tractor engine has been tested on Non Road Transient Cycles (NRTC). Prescribed verification checks show that valid runs of all three cycles were reached. Preliminary results suggest that this approach can be utilized on at least some existing dynamometers not originally designed for transient testing, as long as the dynamometer is rated sufficiently to compensate for its own inertia and to motor the engine. Tests of other engines continue to assess the overall viability of the software.