EVERY time a car brakes, energy is generated.
At present this energy is not used, but new research shows that it is perfectly possible to save it for later use in the form of compressed air.
It can then provide extra power to the engine when the car is started, and save fuel by avoiding idle operation when the car is at a standstill.
Air hybrids, or pneumatic hybrids as they are also known, are not yet in production. Ford had the idea in the 1990s but dumped it.
Nonetheless, electric cars and electric hybrid cars already make use of the brake energy to power a generator that charges the batteries.
But Per Tunestal, a researcher in combustion engines at Sweden’s Lund University, claims air hybrids would be cheaper to manufacture and the step to commercialisation does not have to be a large one.
“The technology is fully realistic,” he said.
“My simulations show that buses in cities could reduce their fuel consumption by 60%.”