Piezo Injectors

  Piezo injectors use piezoelectric technology to open and close fuel injectors at extremely high speeds and precision to inject fuel into an internal combustion engine. These injectors are used in both petrol and diesel engines to improve their persformance and efficiency
.   Piezo electricity results from squeezing or applying pressure from certain crystal like materials or certain ceramics. If this process is reversed and electricity is applied to these same materials they will expand and return to their original size as soon as the electricity is cut off. The expansion of one crystal is too small to see with the naked eye.
  How piezo electricity make piezo injectors work is by using the expansion of the crystals to open the injector. The expansion of one crystal is much too small to open the injector so there are several hundred little piezo crystals placed one above the other covering a length of more than half the injector.
  When electricity passes through these hundreds of crystals their combined expansion is enough to open the injector and as stated before they return to their original size as the electric charge stops. The crystals expand downwards and an upward movement is required to open the injector so two very small levers are used to reverse the process and open the injector and a spring closes it as the crystals retract.
  Piezo injectors are not used any petrol or diesel engine but electrically controlled direct injection engines such as gasoline direct injection (GDI) or common rail diesel engines.
  Because of their operation piezo injectors can open and close much faster than mechanical injectors which allow more precision in the injecting of fuel during the four stroke cycle. Just the right amount of fuel can be used for each stroke whatever conditions the engine may be operating under.
  The ECU determines at exactly what stage of the compression and/or power stroke the piezo injector should be opened and closed. This is monitored by the ECU to the millisecond. In addition to having the right amount of fuel, the engine receives that fuel at the right time, as determined by the engineers of the engine when they were designing it.
  Piezo injectors have the ability to inject fuel into the cylinder several times in one stroke (as many as seven times). This is very useful in a diesel engine where a spark is not used to ignite the fuel. Multiple injections allow a pre, main and post explosion and ensures no fuel is wasted.
  Piezo injectors have greatly contributed to the effectiveness of common rail systems in offering better performance with increased fuel efficiency and has definitely improved the way the internal combustion engine functions.
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