Yesterday, French automaker Peugeot confirmed its plans to bring an all-new hybrid car to the marketplace which will have zero-emissions capability in and around town and the potential to dramatically reduce tailpipe emissions on the motorway. The technology will be officially unveiled at this year’s Geneva Motor Show, and is expected to be offered as an option on the B-segment Peugeot 2008 by 2016.
Unlike other hybrid cars to date however, Peugeot’s new technology won’t use a conventional high-voltage battery pack or an electric motor. Instead, it plans to be one of the first automakers to mass-produce a hybrid air car.
Like electric vehicles, air-engine — or pneumatic motor — cars aren’t new: they’ve been around for more than 100 years. While the idea is sound however, it’s taken a while for materials technology to catch up enough to manufacture an air tank that’s strong enough to hold compressed air but lightweight enough to be used in an energy-efficient vehicle.
Under normal highway driving, the car would be mainly powered by a small three cylinder gasoline engine, producing the same kind of emissions and gas mileage as any modern, lightweight three-banger. But at lower speeds, the engine stops powering the car and an air-powered hydraulic motor takes over, drawing its power from a compressed air tank located down the centre of the car where a traditional transmission tunnel would be.
In the same way that an electric motor can capture kinetic energy under braking and convert it into electrical energy and then stored chemical energy in its battery pack, Peugeot says its hybrid air drivetrain can capture kinetic energy under braking and use its hydraulic motor to compress air back into its storage tank. There’s no word on how efficient this process will be, but based on what we know of current pneumatic motor technology, we’d expect it to be less efficient than an electric motor.
Peugeot claims its hybrid air technology, which it plans to debut in the Peugeot 2009 subcompact crossover in 2016, will get an overall efficiency of around 79 mpg U.S. (94 mpg Imperial, 2.97 litres/100km). That places it above cars like the Toyota Prius C hybrid, but below cars like the plug-in Prius and Chevrolet Volt in the efficiency stakes.
Because the system will operate in a fully autonomous mode, Peugeot says switching between gasoline engine and pneumatic motor will be smooth and seamless, gaining up to a 45 percent improvement in fuel savings.
What isn’t clear from the press releases thus far is if Peugeot plans to make its hybrid air technology a plug-in hybrid, or if the air tank will only be filled by the car when in motion.
In the past, we’ve seen hybrid air vehicles which have included on-board electrically-powered air compressors capable of refilling the air tank from a domestic power outlet alongside a faster air-hose connection for refilling via an external air compressor. We’re not expecting either option to be included at this stage, but we can but hope.
Compared with battery-based hybrid drivetrains, Peugeot’s system could be far cheaper to make, because it won’t require the use of rare earth metals for an electric motor or battery pack. Admittedly, it will also be less efficient than an electric hybrid drivetrain, but it’s likely the technology could give Peugeot a massive improvement in its fleet-wide fuel efficiency in order to meet European emissions standards in the most affordable way it can.
Does Peugeot’s system have any improvement over a battery hybrid vehicle? While Peugeot hasn’t detailed efficiency, we do know that the hybrid air system is better suited to low-speed operation, like many underpowered hybrid electric drivetrains.
Based on what we know of previous air-engine cars however, we can expect Peugeot’s hybrid-air technology to be noisier than a hybrid electric or purely electric car. That said, we’re glad to see an alternative drivetrain technology offered alongside other low-emissions vehicles.
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