The Australian road transport industry faces a fork in the road, as increasing pressure to reduce its environmental impact has fleets searching for ways to reduce emissions without impacting productivity.
While the spotlight often shines on alternative fuels for prime movers, an equally transformative technology is emerging from beneath our trailers: the electric axle, or e-axle.
Encompassing systems that both recover energy and provide supplementary drive, e-axles offer a compelling and practical route to significant emissions reductions and enhanced efficiency for fleets around the country – particularly long-distance trucks that aren’t yet suitable for complete electrification.
The core principle of an e-axle lies in the direct integration of an electric motor into the trailer axle assembly. This unlocks a cascade of potential benefits. Unlike traditional trailers that are purely passive loads, e-axle-equipped trailers become active participants in the vehicle’s dynamics and energy management.
One key advantage lies in regenerative braking. Instead of dissipating kinetic energy as heat during deceleration, an e-axle acts as a generator, converting this energy into electricity. This captured power can then be directed to an onboard battery or used directly to power auxiliary trailer systems.
Consider the implications for refrigerated transport, a significant energy consumer within the industry, as an example. An e-axle could drastically reduce or even eliminate the need for diesel-powered refrigeration units, leading to substantial fuel savings and a quieter, cleaner operation, particularly vital in urban delivery cycles.
It’s already being done too, with companies like McDonald’s trialling the promising technology. At the 2023 Brisbane Truck Show, a McDonald’s fridge trailer built by FTE was on display, featuring a TRAKr e-axle, which is already operating on Australian roads.
Beyond energy recovery, driven e-axles offer even greater fuel consumption and emissions benefits. By providing supplemental torque to the trailer wheels via electric motors, these systems effectively reduce the burden on the prime mover’s engine.
Driven e-axles are particularly beneficial during acceleration, reducing strain on the engine which translates into a reduced fuel burn. Another benefit is the added traction from a driven trailer axle, which could offer stability and driveability benefits.
Globally, innovation in e-axle technology is gaining momentum with major suppliers like ZF and BPW actively developing and deploying systems. `ZF’s offerings encompass both regenerative and drive-assist functionalities, demonstrating significant fuel efficiency gains in European pilot programs, while BPW’s eTransport system focuses on powering auxiliary loads and providing drive assistance.
While direct, large-scale adoption in Australia is still in its nascent stages, the proven success and ongoing development in international markets underscore the technology’s viability and potential for the Australian context.
The economic and environmental benefits for the Australian transport industry are considerable. For refrigerated fleets, the elimination or significant reduction of diesel genset usage translates to direct and substantial fuel cost savings and a decrease in localized emissions.
For broader applications, the reduced demand on the prime mover through drive-assist e-axles could lead to fuel consumption reductions manufacturers like Move Engineering Group estimate to be as high as 50 percent, depending on the application.
Given the vast distances and high fuel costs prevalent in Australian logistics, these percentage savings could translate into significant financial and environmental advantages for fleet operators over the long term.
Beyond fuel savings, e-axles can contribute to reduced wear and tear on the prime mover. The supplementary power from a driven trailer axle eases the engine’s workload, potentially extending its lifespan and reducing maintenance requirements. Similarly, the regenerative braking capabilities of energy-harvesting e-axles can lessen the reliance on traditional friction brakes, leading to lower maintenance costs and improved safety.
While the initial investment in e-axles will be a consideration for Australian transport businesses, the long-term operational and environmental benefits present a compelling return on investment – and it’s certainly a smaller outlay than buying a dedicated electric or hydrogen fuel cell prime mover.
Of course, the technology is still in its infancy but as more manufacturers enter the Australian market with these innovative e-axle solutions, fleet operators will have the opportunity to evaluate their suitability for various applications.
The integration of e-axles represents a significant step towards a more sustainable and efficient future for Australian freight, offering a tangible way to reduce emissions and operational costs from the trailer forward.
