Monday November 24th, 4pm, Mann Hall 323
Abstract: The purpose of this study is to demonstrate methodology for characterization of a plug-in hybrid diesel-electric school bus, taking into account diesel fuel and electricity consumption and emissions associated with each. A plug-in hybrid school bus in Wake County, North Carolina, built by IC Corporation, a school bus manufacturer, and Enova Systems, a provider of hybrid drive systems, was tested. This bus is part of a nationwide program administered by Advanced Energy to deliver as many as 19 such buses to 11 states in a demonstration program. The bus includes a VT365 diesel engine and a parallel hybrid system. The bus is recharged overnight from grid power. During a typical day, the bus initially operates in charge depleting mode until the battery charge reaches a set point, after which it operates in charge-sustaining mode. The power consumed by the bus during recharging is measured with a watt-hour meter. Four systems were used for in-use monitoring of the bus: (a) electronic download from the hybrid control system interface for factors such as battery charge and power consumed by the electric motor; (b) download of CAN-bus data from the vehicles electronic control system for factors such as engine RPM, manifold absolute pressure, intake air temperature, road speed, and others; (c) portable emission monitoring system (PEMS) measurement of selected engine variables and exhaust gas concentration; and (d) GPS monitoring of coordinates and altitude. These data are used to characterize the activity patterns of the bus, the energy flow associated with the batteries, electric motor, and diesel engine, and the tailpipe emissions. Data collection was also conducted for a conventional control bus of the same chassis and engine, but without the hybrid system. Results are presented based on in-use data collection during an actual duty cycle (including transport of school children), in order to demonstrate methodology for integrated analysis of a plug-in hybrid system and comparisons to conventional technology.