One of the tools automakers use in electric cars to combat drivers' range anxiety is a range-extending gasoline engine.
These engines essentially act as generators, providing electricity to power a car's electric motor and only rarely driving the wheels directly, if at all.
This provides added flexibility for drivers who want to take longer trips, or who may find themselves without ready access to charging stations.
Range extenders have also piqued the interest of French carmaker PSA Peugeot Citroën.
PSA is now testing small range extenders made by Israeli startup Aquarius Engines, according to Reuters.
"We are evaluating the technology," PSA R&D director Gilles Le Borgne told the news agency, adding that "nothing has been decided yet" regarding use in future production cars.
2015 BMW i3 REx charging at The Oaks Hotel, Paso Robles, California [photo: Jeff Pantukhoff]
While many range extenders have been repurposed from internal-combustion engines, Aquarius takes a more basic approach.
Its engine is a 0.60-liter, single-cylinder unit, with no valves.
While the valve-less concept is fairly novel, established carmakers have employed very small range extenders before.
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The current BMW i3 REx uses a 0.65-liter 2-cylinder engine, and Audi built a small fleet of prototype A1 e-tron electric cars that used tiny Wankel rotary engines as range extenders.
Aquarius believes the compactness of its engine and its low cost—it suggests a total vehicle manufacturing cost of $17,000 per car—will make it attractive to carmakers looking to meet stricter global emissions standards.
A lighter and more efficient gasoline range extender will allow automakers to sell electric cars with smaller battery packs, reducing cost in that area, Aquarius reasons.
Audi A1 e-tron Dual-Mode Hybrid
Renault, PSA's French rival, reportedly investigated the Aquarius system and opted to pass on it.
Renault and its partner Nissan together have built more all-electric cars than any other company, recently passing the 340,000-unit mark.
In comparison, PSA has shown relatively little interest in electric cars.
It currently sells re-badged Mitsubishi i-MiEVs as the Peugeot iOn and Citroën C-Zero, the Citroën E-Mehari crossover, and electric versions of the Peugeot Partner and Citroën Berlingo vans.
The company may soon get a strong incentive to launch more electric cars, though.
European Union regulators are reportedly drafting stricter emissions standards that would take effect after 2021, the limit of the current set of standards.
[hat tip: Brian of Israel]