| Abstract |
Electric vehicles (EVs) are now seen as a possible solution to alleviate air pollution in cities, because
of their zero emission characteristics. Limitations to the acceptance of EVs are due to the moderate
performance of the traditional battery, mainly the range limitations between two consecutive charges, the
lengthy time taken for recharge, and the modest service life. This limitation is overcome to a certain
extent by Hybrid Electric Vehicles (HEVs). HEVs save energy and minimise emission by combining the
superior characteristics of both Electric Motors and the Internal Combustion Engine (ICE). Electric
Motors are capable of operating from no load to full load over the entire speed range, and ICEs have
optimum performance at fixed speed and near full load. In a series Hybrid Electric Vehicle, the steady
state cruising energy is supplied from the ICE, and the peak energy demands during acceleration and the
other specified operational missions will be supplied from the battery through Electric Motor.
ER&DCI(T) is developing an HEV suitable for operation in metros. Different types of Urban Driving
Schedule have evolved. In this paper, a driving schedule for a typical Indian metro is selected. HEV
operation is simulated with this cycle, and simulation results are presented. During acceleration, vehicle
needs positive tractive power; while decelerating negative power is generated by the motor; under
cruising steadily the vehicle needs only a steady state power, which is usually a small percentage of the
peak power requirement. The tractive power is supplied from the battery by the electric motor; a major
portion of the regenerative energy during deceleration is absorbed by the battery, and the steady state
power is supplied by the down sized ICE . The simulation is carried out with different ratings and
operational characteristics of battery and ICE, and an optimum specification for the different blocks of
the HEV is arrived. The results and the specification arrived, are presented in the paper. |
