The purely air-powered can’t may not be a reality, but PSA Peugeot Citroen’s new Hybrid Air powertrain is a clever way to use compressed air to store energy for later use.
Let’s be clear: There’s no such thing as a truly air-powered car. But PSA Peugeot Citroën has a new take on how to use compressed air to store energy that a car can use for propulsion. Showcased in two concepts, a Citroën C3 and a Peugeot 208, the Hybrid Air system powertrain combines air, hydraulics, and gasoline. Peugeot claims its system improves fuel economy by 35 percent and is capable of 81 mpg in the New European Drive Cycle test. A projected price of about $26,000 means the Hybrid Air would be roughly $7700 less than what a Toyota Prius costs in Europe. If Peugeot brings out the Air Hybrid in 2016 as promised, it could challenge electrical batteries as a hybrid power reservoir.
How it Works
An 82-hp 1.2-liter gasoline engine provides most of the power, driven through an epicyclic automatic transmission. During deceleration, the wheels’ energy drives a hydraulic pump that pushes hydraulic fluid into an accumulator and compresses the nitrogen gas within. When the car needs to accelerate, the system works in the opposite way: The pressurized nitrogen gas pushes the hydraulic fluid, which drives a hydraulic motor connected to the transmission.
Gas only: Intended for highway driving
Air only: For speeds below 43 mph, where the engine stops and hydraulics power the wheels 80 percent of the time
Combined: Powered by the gas engine and hydraulic motor
Hydraulic systems are an established technology. The motors and pumps are simple, relatively low-cost, and easy to package—as are epicyclic gears—so the Hybrid Air could be lighter and cheaper than a gas–electric hybrid. And unlike chemical batteries, hydraulics have fewer recycling issues.
With no big battery to run the air conditioning at standstill, the engine would have to run, using gas; a crash-safe accumulator large enough to hold the requisite amount of pressure (up to 4351 psi) might be heavy enough to negate any benefit. With unproven reliability, hydraulic systems could find it difficult to gain consumer acceptance.
post by: ARIYAN