Condensation of Real-World Drive Cycle into Synthetic Drive Cycle - An Innovative Method to Predict Real Driving Emissions



SAE WCX Digital Summit
Authors Abstract
The stringent emission regulations have put enormous pressure on auto manufacturers to develop vehicles with the required conformity factor (CF) on real driving emissions (RDE). However, evaluation of CF on multiple and varying real-world cycles by portable emission measurement system (PEMS) is extremely tedious and expensive. In the present work, a unique methodology is developed to condense any real-world drive cycle into a synthetic drive cycle with a reduced duration that can still match the essential driving characteristics of the real-world cycle. The principal parameters such as average velocity, gear utilization, acceleration, deceleration, cruise duration, engine idling duration, exhaust gas temperature, etc. are collected during the real-world cycle. An innovative algorithm called Real World Cycle Condenser (RWC2) is used to condense the real-world cycle into a synthetic drive cycle. The algorithm is designed to match the principal parameters between the real-world cycle and the synthetic cycle by doing permutation and combination of different driving index of micro-trips calculated from a large duty cycle. With this unique approach, the emission values of any real-world cycle could be easily validated by measuring the emissions of the condensed synthetic cycle in a chassis dynamometer. Moreover, a high level of correlation could be established by comparing the fuel economy and emission results of the original real-world cycle and the condensed synthetic cycle measured in the chassis dynamometer.
Hence, the proposed approach can potentially eliminate or reduce the need of using a PEMS equipment for extensive RDE development. The reduced duration of the synthetic cycle gives a great advantage since the emission of any drive cycle (irrespective of the duration) could be collected without overshooting the limitations of emission collection bags of the chassis dynamometer. Thus, the proposed approach could be used for developing vehicles with compliance on future emission regulations including RDE.
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RT, S., Bose, A., and Ibrahim, M., "Condensation of Real-World Drive Cycle into Synthetic Drive Cycle - An Innovative Method to Predict Real Driving Emissions," SAE Technical Paper 2021-01-0602, 2021,
Additional Details
Apr 6, 2021
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Technical Paper