BMW tests diesel-electric semi combination

The BMW test combination involved standard European-spec MAN and Volvo diesel-powered prime movers, pulling a modified tri-axle semi-trailer. The trailer was fitted with an electrically-powered centre axle and lithium ferro-phosphate battery banks.

The electric drive axle fitted to the trailer had a staggering 13,000Nm torque rating.

Integrated sensors on the kingpin between the prime mover and the trailer ensured an optimum power delivery between the diesel and electric motors and best-possible fuel economy.

As well as reducing the prime mover’s energy consumption when cruising, the e-trailer’s powered axle also provided additional power during start-up and on grades.

The trailer was loaded with 16 tonnes of payload and the combination was tested on the German highway system around hilly Lower Bavaria and on a 420km haul to Leipzig.

A trailer battery range of more than 600 kilometres without recharging was achieved, however, even when the trailer batteries were depleted, the truck driver suffered no range anxiety, because the diesel prime mover could soldier along unaided.

The concept of powered trailers and road-train dollies isn’t new to Australian remote area operators, who have used diesel-powered trailing equipment for many years. However, an electrically-powered trailer behind a diesel prime mover is an innovation.

The fuel savings when using e-trailers are countered by their heavier weight and resulting lower payload, but this is partially offset by an increase in the permissible total weight for trailers in the EU. Australia is already trialling heavier axle weights for low- and zero-emissions trucks.

The e-trailer’s battery was charged carbon-neutrally, using 100 per cent green energy, meaning that a single electric trailer could facilitate a CO2 reduction of around 120 tonnes per year.

The higher purchase price of an e-trailer is countered by lower operating costs, BMW and Trailer Dynamics asserted. Over long distances in particular, the use of e-trailers can facilitate a significant decarbonisation of the existing fleet while simultaneously saving costs.

The test e-trailer had its battery bank installed in an under-frame box that would make battery-swap systems a possibility for the longer-distance hauls in markets such as Australia.

At the conclusion of this first set of tests, Michael Nikolaides, Head of BMW Group Production Network and Logistics, said: “As the BMW Group, we are committed to the target of complete climate neutrality throughout the entire value chain.

“The testing with Trailer Dynamics’ e-trailer showed that using this kind of electrified semi-trailer significantly reduces the fuel consumption of standard diesel tractors and noticeably increases the range of e-trucks,” he added.

Trailer Dynamics’ vision is to make a significant contribution to decarbonising the economy with e-trailers and to promote sustainable and zero-emission logistics.

“With our partner BMW and the forwarding agents Gahr International and Elflein Spedition & Transport, we are taking the next important step in making our vision a reality,” said Abdullah Jaber, CEO and Managing Director of Trailer Dynamics GmbH.