|Scania’s ethanol hybrid.|
Scania will introduce its ethanol-fueled hybrid bus concept at the UITP public transport congress in Helsinki 21-24 May 2007. The full-size low-floor city bus is designed to cut fossil CO2 emissions by up to 90% when running on the ethanol blend and reduce fuel consumption by at least 25%.
The series hybrid powertrain combines a 9-liter diesel engine genset adapted to run on ethanol with a 150 kW traction motor and 4 125V Maxwell BOOSTCAP supercapacitors for energy storage. The new Scania concept bus, which also meets Euro 5 and EEV emissions standards, is the result of a three-year development project conducted at the Scania Technical Centre in Södertälje, Sweden.
|The series hybrid configuration. Click to enlarge.|
The engine is an adaptation of Scania’s latest 9-liter diesel engine with air-to- air charge cooling and exhaust gas recirculation, EGR. The 5-cylinder engine has unit injectors for each cylinder and a compression ratio of 28:1. Power output is 199 kW (270 hp) at 1,900 rpm and torque is 1,200 Nm (885 lb-ft) at 1,100-1,400 rpm. The engine is mated to a water-cooled Voith ELVO Drive TFM Generator.
The traction motor is a water-cooled Voith ELVO Drive which delivers maximum torque of 2,750 Nm (2,028 lb-ft), and continuous torque of 1,800 Nm (1,328 lb-ft) with a maximum speed of 2,400 rpm.
|Supercapacitors on the roof. Click to enlarge.|
The Maxwell supercapacitors store more than 400 Wh of energy.
Twelve conventional ethanol buses equipped with Scania’s hybrid-drive system will start regular operation in Stockholm in 2008 and 2009 in cooperation with the city’s public transport operator, SL (Storstockholms lokaltrafik). Ten of these are partly financed by the Swedish Energy Agency.