In modern common rail diesel systems,piezoelectric injector is highly used thanks to its excellent performance,better efficiency and lower emissions.It's mainly applied in luxury brand diesel cars,such as Mercedes-Benz,BMW,Peugeot,Citroen,Land Rover,etc.
The most vital component in Piezo injector is Piezoelectric crystal which is featured with polarity deformation characteristics.It generates an electrical charge when a mechanical stress is applied. Likewise, the crystal will change shape when an electrical charge is applied.
In order to meet the demand of multiple injector events to occur per combustion cycle,Piezo (short for piezoelectric) injector is developed.The standard injector using coils to open the injector,resulting in limiting the response time.The piezo injector change coils to crystal,bringing 5 times rapid response and making it suitable to act as the actuator in a diesel fuel injector.
How piezo injector work?
Thanks to peizo injector,high pressure fuel is constantly delivered to the tip of the injector where a needle rests and blocks fuel from being injected.Pressurized fuel is delivered to the top of this needle as well, the force of which keeps the needle closed. When the Piezo crystal is energized, a valve at the top of the needle opens, allowing the pressurized fuel at the top of the needle to return to the tank through the return line. With no pressure at the top of the needle, it springs open, allowing fuel to be injected into the combustion chamber. When the Piezo actuator is de-energized, the valve closes and high pressure fuel forces the needle to return to the closed position. The injection process occurs extremely fast.