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Why choose Piezo Fuel Injectors?

Posted on 1/19/2016 11:46:30 AM

In order to meet the coming rule of Euro 6,common rail engines manufacturers are pay more attention to reduce its emssions.Then Piezo fuel injector will help a lot by using piezo crystals as part of a rapid actuator to make the combustion of the fuel within the cylinder more efficient,injecting fuel in smaller volumes, more frequently and more highly atomised produces less unburned fuel and, in turn, a cleaner burn with less emissions. 

Piezo injectors work by passing electrical current through a stack of Piezo crystals, causing them to expand; as the crystal discharges the current it contracts to the original size. The expansion and contraction of the crystals displaces the fuel within the injector, causing the needle valve to open and close extremely quickly.Comparing to the conventional electrohydraulic solenoid injectors,the piezo injectors is five times faster in delivering  fuel into the combustion chamber.So it brings more injections per cylinder stroke with higher fuel system pressures.It results in improved combustion control, less fuel wastage, a considerable reduction in emissions, more torque and power and better fuel economy.

Cross Section of a Piezo Injector


Common Repair & Replacement Issues
Like all other common rail parts,these piezo injectors are also manufactured to very fine tolerances.
If there is any failure,it usually comes from mis-fueling or high water content in the fuel (through lack of servicing or contamination within the fuel system).

We all know that the common rail injectors work in high temperatures (up to 350°C) environment.At the same time,they have the responsibility to deliver fuel to the combustion chamber accurately, quickly and at extremely high pressures.In some cases combustion blow-by past the injector from the combustion chamber can occur. This leaves carbon deposits between the injector and cylinder head which often requires specialist tools for removal of the injectors. Thorough cleaning of the injector aperture and seal seats, the use of high quality seals along with the correct tightening torque when installing the new/remanufactured injectors can help to prevent these types of problems in the future.

Lots of the motor manufacturer is using the piezo injectors,among which most popular is Renault 2.0 dCi engine.But it doesn't mean it is the endness of the solenoid injector.Because the equipment manufacturers are also finding ways to make the same effect from solenoid injectors

A Word of Caution
Because the injetor could reach to 200 volts and 15 amps,it would be dangerous for Piezo diagnosis.
If disconnected while the piezo crystals are expanding they will not be able to ground and the injector will remain in the expanded state.
So don't disconnect these injectors when the engine is running.After only a few engine revolutions enough fuel will have entered the cylinder to cause hydraulic lock and serious engine damage, not to mention the risk of electric shock.

In order to meet Euro 5,all new cars have to satisfy the demand of emissions in particulates (soot) and NOx (nitrogen oxides)Nowadays emissions of diesel engines is reduced to levels similar to petrol vehicles because of Euro 5.

New cars are forced to meet the Euro 6 from September 2015 which will help to reduce diesel cars’ NOx emissions.It will bring as clean as petrol cars in terms of pollutants. Some models already meet these standards.

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