Piezo inline injector
The piezo principle is an ideal complement for common rail fuel injection. Piezo crystals change their structure in a few thousandths of a second by expanding slightly when an electrical voltage is applied to them. Several hundred piezo wafers are stacked inside each injector, and the expansion of this cluster – less than a tenth of a millimeter – is transmitted directly to the injector needle.
The injectors close again after one or two thousandths of a second. In this way very small amounts of fuel weighing as little as 0.8 of a milligram can be injected. The fuel leaves the nozzle holes at a speed that can be as high as 2,000 km/h (1,242 mph).