Zurich (Switzerland) - Swiss engineers believe they've developed an alternative, competitive technology to electric hybrids such as the popular Toyota Prius which could someday make hybrids more globally affordable. They are referring to something called a pneumatic hybrid.
Pneumatic hybrid technology is being developed by professor Lino Guzzella and his team through the Swiss Federal Institute of Technology Zurich (ETH). Guzzella describes the pneumatic concept as being similar to that of electric, but with the engine having a compressed air tank connected instead of a battery unit. "When required, e.g. when starting from rest or after changing gear, compressed air flows into the engine through an electronically controlled valve. If fuel is also injected, the engine responds quickly," he said.
The research engine utilizes air power to supplement the gasoline engine's power. While this makes it a hybrid engine, there is no battery or electric motor and the number of gasoline engine pistons is reduced from four to two.
The ETH reports this compressed air supply allows for engine downsizing, halving the number of cylinders from four to two. This is said to reduce frictional losses by half as well as increase average overall efficiency. Power loss is compensated for by an installed turbocharger, which "exploits the exhaust gas enthalpy as an energy source."
Initial tests in the European Test Cycle reportedly show the engine's average efficiency increases from 18 to 24 percent, resulting in a fuel savings of one-third. It is said that, although the fuel savings achieved by the pneumatic hybrid are not as large as that of an electric hybrid, it offers a better price-performance ratio - since it does not require expensive batteries which decrease in efficiency over time.
ETH reports that their new engine concept has aroused the interest of several major motor companies and automotive suppliers, who have obtained information from on-site visits.
See the Swiss Federal Institute of Technology Zurich article.