Automotive

Ultralight foam-core runabout squeezes mileage out of small fuel cell

Ultralight foam-core runabout ...
With a weight under 1,000 lb and a hydrogen fuel cell electric powertrain, the SLRV makes for a clean, efficient commute
With a weight under 1,000 lb and a hydrogen fuel cell electric powertrain, the SLRV makes for a clean, efficient commute
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DLR shows the SLRV and U-Shift working prototypes at IAA Mobility 2021
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DLR shows the SLRV and U-Shift working prototypes at IAA Mobility 2021
With a weight under 1,000 lb and a hydrogen fuel cell electric powertrain, the SLRV makes for a clean, efficient commute
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With a weight under 1,000 lb and a hydrogen fuel cell electric powertrain, the SLRV makes for a clean, efficient commute
Underneath the SLRV skin
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Underneath the SLRV skin
Putting the wheel cladding on the SLRV
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Putting the wheel cladding on the SLRV
DLR gives the SLRV a low, aerodynamic shape, assisting in its efficiency
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DLR gives the SLRV a low, aerodynamic shape, assisting in its efficiency
The lift-up canopy provides entry to the two seats inside and offers a clearer, uninterrupted view of the vehicle's surroundings
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The lift-up canopy provides entry to the two seats inside and offers a clearer, uninterrupted view of the vehicle's surroundings
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A cleaner, zero-emissions fuel cell-electric powertrain is one way of lessening a vehicle's impact, and cutting the vehicle's weight so that the powertrain can push the vehicle farther every fill-up is another. And with less weight, you can shrink the powertrain, which lessens weight even more. That's the cycle in which the German Aerospace Center (DLR) is operating with its Safe Light Regional Vehicle (SLRV). The eye-catching prototype uses a small fuel cell/battery-based electric powertrain and ultralight metal-foam structure to serve as a capable mobility solution in the city and beyond. And it looks much cooler than the average green car, too.

The brief behind the 12.5-foot (3.8-m) SLRV was to create a lightweight, safe and affordable vehicle – a trio of adjectives that reads like a "choose any two" scenario. The metal-foam construction serves as the backbone of the design, featuring in the front and rear crumple zones that protect critical vehicle components and in the structural ring that wraps the pod-like two-seat passenger cell to deliver energy-absorbing impact protection. The entirety of this foam-sandwich structure weighs a mere 199 lb (90 kg), contributing heavily to a total vehicle weight that dips under four figures at 992 lb (450 kg).

The lift-up canopy provides entry to the two seats inside and offers a clearer, uninterrupted view of the vehicle's surroundings
The lift-up canopy provides entry to the two seats inside and offers a clearer, uninterrupted view of the vehicle's surroundings

DLR continues its weight-saving efforts with the powertrain, a combination of a small fuel cell, small battery and dual-motor rear electric drive. The agency says the fuel cell/battery setup weighs less than a conventional battery. Using hydrogen from a 39-L (3.5 lb at 700 bar) pressurized tank in between the seats, the fuel cell puts out a continuous 8.5 kilowatts, and the battery kicks in extra power up to a system max of 25 kW to increase acceleration. The combination delivers a range up to 249 miles (400 km) and speeds up to 75 mph (120 km/h). Meanwhile, waste heat from the fuel cell gets repurposed as cabin heating, insulated in cold weather by the efficient thermal barrier of the sandwich structure.

For comparison, the 3,990-lb (1,810-kg) Hyundai Nexo's fuel cell and battery combine for a total output of 135 kW, powering the car up to an estimated 380 miles (612 km) per 156-L (13.8 lb at 700 bar) hydrogen tank.

The SLRV meets European standards as an L7e heavy quadricycle, and DLR imagines it finding use as a private commuter car, shuttle between transportation hubs and car-sharing solution. The agency believes the rapid-refueling capability of the hydrogen system makes it ideal for regional journeys between the city and suburbs, hence the name. The project team estimates that the car would retail for as little as €15,000 (approx. US$17,700) and enjoy a lifespan of roughly 186,000 miles (300,000 km), making it an affordable, efficient mobility solution.

DLR shows the SLRV and U-Shift working prototypes at IAA Mobility 2021
DLR shows the SLRV and U-Shift working prototypes at IAA Mobility 2021

DLR introduced the first working SLRV prototype about a year ago and showed it again at last week's IAA Mobility event in Munich, alongside the boxy U-Shift modular urban transporter. The SLRV serves as part of the agency's Next Generation Car (NGC) project, which aims to identify and develop technologies to support the future of city and intercity transportation and to optimize associated manufacturing technologies. DLR isn't sure the SLRV will make it to the market as a full vehicle, but it does expect some of the project's technologies to find their way into next-gen vehicles.

Source: DLR

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3 comments
3 comments
Alexander Lowe
A minor point, and not necesarily a criticism: why are the wheels housed in separate pods? It may make little difference, but if the car's main selling point is eergy effieciency, wouldn't it's aerodynamics work better if all the wheels were faired into the bodywork, and covered so far as possible, to reduce drag?
Adrian Akau
Alexander. Back wheels can easily be faired into the bodywork and covered (with a cover that can be removed if the tire has to be changed) but it is not so easy with the front wheels because they stick out when turning. One solution to the front wheels is to make a cover that will retract if the wheels are turned but this is not easy or affordable. I speak from experience on the back wheels because I modified a Toyota Echo to reduce the coefficient of air friction. My main concern with this vehicle is the 700 bar pressure (7 x 14.8 lbs/sq. inch) pressure needed to supply the hydrogen. I think the answer later on will be to have an onboard system which will extract hydrogen from a hydrogen compound such as ammonia (NH3) at much lower pressure and then to feed it into the fuel cell.
Adrian Akau
Correction: 700 bar is 700 x 14.8 lbs/sq. inch.