Page 195 - Automotive Engineering Powertrain Chassis System and Vehicle Body

Hybrid vehicle design CHAPTER 7.1

Fig. 7.1-18 Unique Mobility small hybrid bus: (a) Unique Mobility midibus; (b) power flow charts.

The 100 passenger vehicle had a maximum speed of of a city bus to be 750 kW for absorbing the kinetic
43 mph and the 19 tonne GVW vehicle had batteries energy of the vehicle at top speed and a 220 lb flywheel
weighing 3.5 tonnes. The motor could develop up to was chosen, with a 1500 kW total energy to allow
200 bhp while the diesel engine was rated at 100 bhp. a reserve, which suffered 2 kW power loss at
The five 275 Ah batteries operated at 360 V. 12 000 rpm. For a typical urban operating cycle, char-
At the same period a Daimler-Benz 305 was also acteristics were plotted, from the starting point of the
converted to flywheel hybrid operation in a study which bus stationary with diesel engine at idle and flywheel
involved MAN and Berlin University, too. The team charged up from previous operation, for the configura-
calculated the flywheel storage energy requirements tion shown at (b).

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