ZF’s new electric portal axle for city buses
ZF’s Commercial Vehicle Solutions (CVS) division has introduced the AxTrax 2 LF, a low-floor electric portal axle designed to meet the needs of sustainable passenger transportation.
“As cities worldwide transition to zero-emission public transport, there is no getting around the electric city bus. The demand for efficient electric drivetrains in modern full low-floor buses is growing rapidly,” said ZF.
The AxTrax 2 LF addresses this need. Designed specifically for low-floor city buses, it builds on its predecessor, the AxTrax AVE, and forms part of ZF’s modular e-Drive kit to deliver both higher performance and greater efficiency.
“The electric drive consumes up to 20 per cent less energy in standardised SORT driving cycles compared to the previous model, helping to reduce the total cost of ownership (TCO) for operators,” the company said.
“The improved efficiency is largely attributed to ZF’s newly developed in-house electric drive platform, which brings advanced technologies from high-volume commercial vehicle applications into the city bus segment.
“These include a permanent magnet synchronous motor (PSM) with hairpin winding technology and a silicon carbide (SiC) inverter operating on an 800V architecture.”
The compact design of the AxTrax 2 LF helps to maximise the available space for the passenger compartment or batteries, says ZF, enabling passenger-friendly bus design concepts.
Fitting a similar installation space to the predecessor AxTrax AVE, the new axle is fully compatible with ZF’s air suspension and wheel-end solutions.
On the software side, AxTrax 2 LF also benefits from ZF’s extensive experience in producing advanced functionality such as axle condition monitoring and cyber security.
“Highly efficient and powerful, AxTrax 2 LF is available in two variants. These offer continuous power outputs of 260 kW and 360 kW and peak torques of 22,700 Nm and 37,300 Nm. The higher performance of the electric motors also enables more energy to be recovered.
“The continuous power of the AxTrax 2 LF with 360 kW is about twice as high as the AxTrax AVE. As a result, articulated buses with only one electric drive axle – either operating as a pusher or puller – can be used even in challenging topography.
“It is also possible to equip articulated buses with two AxTrax 2 LFs to meet applications where increased traction is required.”
