When you have more than 11,500 retail outlets and register some $626 billion in annual sales, you need to shift a lot of inventory around.
So US group Walmart has its own logistics company with a fleet of 6100 prime movers and 61,000 trailers to do the job.
Each of its 7800 drivers averages 160,000km a year between distribution centres and the Walmart store network.
That’s why when the company’s logistics bosses saw a concept truck at a show in Germany, they decided they could and should drive a similar innovation back home in the US. The company enlisted Peterbilt, Great Dane Trailers and a high-tech turbine company, Capstone Turbines, to develop a technological platform that could lead innovation and drive down transport costs for its fleet.
The tech mix was leading edge. A micro-turbine spinning at 96,000rpm on a patented air bearing that uses no oil, requires no maintenance and reduces operating friction losses to microscopic levels.
Because the turbine housing itself is air cooled by the process, there’s no cooling system, coolant or antifreeze needed.
No radiator means about 20 per cent improvement in aerodynamics over Walmart’s fleet of Peterbilt diesel trucks.
That in itself slashes fuel consumption by 10 per cent.
The turbine can burn a variety of fuels — diesel, kerosene, natural gas and biofuels, and the burn is clean. Because the exhaust is clean there is no need to use exhaust scrubbers or chemical treatment to meet US emissions standards.
The turbine and compressor blades are fixed to a single shaft, which is the only moving part in the engine. The compressor sucks in air to a combustion chamber where fuel raises the temperature in excess of 1500F (815C). The heated air rapidly expands, spinning the turbine’s blades and driving the compressor.
The rest of that mechanical energy is used to run a generator.
The generator tops up a lithium battery pack which can drive the truck’s electric motors for up to 50km when the turbine kicks in as a range extender.
The usual mix of regenerative braking pushes that electric range out further.
Walmart estimates its concept truck will reduce fuel consumption by 55 per cent over long routes and by 241 per cent over shorter routes when its micro-turbine and electric motor can be put to best use.
With an aerodynamic brief that saw no boundaries, Peterbilt designed a cabin straight out of the Batcave. The driver sits in the centre and the compact turbine allows the power pack to be under the floor. Sliding swing doors allow easy entry/exit and a living area behind the driver cockpit is expansive.
The van body is almost all exclusively carbon fibre, which according to Great Dane Trailers, is 10 times stronger than steel but lighter than fibreglass, saving 1.8-tonnes in tare weight. Tightening the gap between the truck and trailer reduces aerodynamic swirl further.
Although this truck in its original form will never make it to series production, it’s a dynamic platform to explore possibilities and test new technologies in a work environment.
And it has to be the coolest delivery rig on the road.