Virginia Tech Comprehensive Power-Based Fuel Consumption Model

Abstract

Few models estimate fuel consumption and carbon dioxide emission levels of diesel and hybrid buses. Models that are available either require the gathering of significant dynamometer data to calibrate the model parameters or produce a bang-bang control system, which results when optimal control entails use of maximum throttle and breaking use. This paper extends the Virginia Tech Comprehensive Power-Based Fuel Consumption Model (VT-CPFM) to model diesel and hybrid buses. The bus parameters are calibrated with publicly available data from the Altoona Bus Research and Testing Center in Altoona, Pennsylvania. The research presented in this paper analyzed 10 standard diesel buses and three hybrid buses. The VT-CPFM estimated fuel consumption levels on the Orange County bus cycle dynamometer test with an average error of 4.7%. The estimation error was less than 6% for all except two buses, with a maximum error of 10.66% for one hybrid bus. The VT-CPFM was also validated with on-road fuel consumption measurements that were derived by creating drive cycles from acceleration information; these measurements produced an average estimation error of 22%. These higher errors are probably attributable to the in-field drive cycles, which had to be constructed because none were available.