Virtual Test Bed (VTB) based Engine Calibration: Unique approach to ensure engine component protection & to meet WNTE in different environment condition for Medium Duty Diesel Engine

In this paper a VTB (Virtual Test Bed) based approach were used to virtually calibrate the medium duty diesel engine for component protection in different combination of environment pressure and temperature, also to calibrate thermal requirement to ensure sufficient heating of ATS (After Treatment Systems) to reduce tail pipe emission. In view of BS6 emission norms implementation, the emissions are not only confirmed in standard condition but also in non-standard condition including different combinations of ambient temperature and pressure especially in NOx emission in WNTE cycle. However, achieving the emissions in different environment condition requires physical emission calibration in such conditions. Hence engine must be calibrated in climatic test chambers to ensure emission in different altitude condition and to save the time. But these test beds are quite expensive hence minimum time of these test bed preferred to save calibration cost. Hence VTB based calibration were done initially to reduce significant time of climatic testbed calibration. In VTB test bed AVL specific models were used along with physical component of engine to virtually simulate the engine. Hence all the calibrations were done primarily on virtual test bed especially for engine component protection & thermal requirements. With increase in altitude the medium duty engine reaches to component limits especially in turbine inlet temperature, compressor outlet temperature and turbocharger speed in operating conditions. Hence these parameters were brought under the safe limit with minimum derating strategy in targeted ambient combinations in VTB itself. The modern engines are equipped with after treatment systems (ATS) hence there quick heating is always needed especially for SCR (selective catalytic reduction) to ensure tail pipe emissions. In these engines thermal managements employed for quick heating of SCR, hence VTB based virtual calibration done for thermal management in different environment condition to ensure enough heating of ATS to reduce tail pipe NOx. Later these calibrations were verified in climatic test cell with physical engine for various combination of environment conditions in pressure and temperatures. By this approach a considerable time & efforts of climatic test bed calibration were saved. Finally, a correlation in VTB calibrated results & physical engine test results on climatic test bed were shown for engine protection and WNTE emissions. Keywords: Engine Protection, Climatic Calibration, HIL/ VTB Based calibration, WNTE calibration, ATS Thermal Management.