piezo fuel injection

Here is an excerpt from MIT Technology magazine

Fuel injectors transformed the automotive industry, increasing gas mileage and decreasing emissions. Researchers at Siemens VDO Automotive are set to launch another revolution in internal combustion with injection jets constructed from piezoelectric materials, which change shape in response to electrical current.
Originally developed for diesel engines popular in Europe, the jets are being adapted for gasoline engines and are expected to reduce fuel consumption by as much as 20 percent, while improving engine performance and emissions. “The piezo enables very fast, precise injection control,” says Brian FitzGerald, director of Siemens Diesel Systems North America. As soon as the piezo element receives an electrical impulse, it expands, actuating the nozzle needle and opening the injection valve within two-tenths of a millisecond. The fuel is directed straight at the spark plug, rather than at the cylinder wall. Fuel ignition occurs only if the amount of fuel and the injection timing are precisely calibrated — and that’s exactly what the piezo injectors, with their rapid response, excel at. Peugeot has begun incorporating the diesel version of the system into its cars in Europe, and six other manufacturers plan to follow suit. Siemens hopes piezo injection will prove as popular for gasoline engines.