British bus manufacturer Alexander Dennis Ltd. (ADL) is expanding its product line, adding a double-decker model powered by a fuel cell drive. This new model is also equipped with ZF’s AxTrax AVE electric drive axle. ZF also provides additional hardware and software solutions for optimum performance. An initial prototype is now operating at high efficiency in field testing.
ZF’s AxTrax AVE electric drive axle drives low-floor buses up to a maximum axle load of 13,000 kilograms. The electric motors integrated into the wheel heads have a total output of 250 kilowatts.
The bus, designed by ADL, is based on ADL’s Enviro400 product line. This configuration comprises a secure system that converts hydrogen into electricity, which, in turn, drives two electric wheel-hub motors in the electric portal axle.
ADL spent two years developing this hydrogen-driven double-decker bus with ZF selected as a partner from the beginning. During field testing, the prototype operated along actual bus routes in several cities throughout the United Kingdom.
In addition to the AxTrax AVE, ZF also provided the inverter, the EST 54 electronic control unit and the appropriate control software. In this complete system, the company aligned performance, efficiency and the service life of the drive while reducing test and homologation costs for ADL.
The British manufacturer has already presented the prototype of the new fuel cell double-decker to the public as well as several fleet operators.
ZF introduced the AxTrax AVE in 2012. The electric drive axle can be used in a wide array of applications as it can not only be operated in the fuel cell configuration, but also as hybrid or purely electrically driven with lithium-ion batteries.
In addition to the excellent drive performance—totaling 250 kW up to a maximum axle load of 13,000 kilograms—the compact design is also advantageous for packaging considerations.
Since neither a conventional unit nor a universally jointed shaft is necessary for transmitting power, manufacturers now have more freedom to configure the passenger compartment to their design preferences. They can add seating and standing room, for example, or provide for step-less entry and exit or a completely flat passageway.