The effect in which a material generates an electrical charge in response to a force (mechanical stress) applied to it is what is known as Piezoelectricity. Heat and Pressure can be the mechanical stress. However, piezoelectricity works conversely. Piezoelectric fuel injector fundamentally works by applying an electrical current to a material. This results in a change such as pressure or movement in that material.

Piezoelectic Fuel injectors have what are called “stacks” of Piezo material in them stacked on top of one another. Individually, they are slices. This material moves around two-hundred-thousandths (.00002) of an inch when electricity is applied to the “slice” of piezo material inside of the fuel injector. Because this is not enough to move the nozzle which controls the flow of fuel is why the slices are arranged in a stack. When electricity is applied to this stack, the total movement is increased to four-thousandths (.004) of an inch. This is enough movement to open and close the nozzle of the fuel injector, controlling the flow of fuel. 

Piezo Stack Regeneration

A critical step in the remanufacturing process includes piezo stack regeneration. From continued use over time, the piezo crystal stack used in this style of GDI injectors can expand from continued operation at low engine speed. This causes slower injector response time. This will also reduce injector flow rates under high fuel demands, when not often used. This condition results in poor idle quality and poor performance under higher engine loads. It is similar to battery banks. When the piezo crystal stack does not operate in a certain range, it “forgets” that is is possible to do so.

The regeneration process we do at Injector-Rehab is accomplished by operating the injector under specific operating conditions. Varying pressure, heat and voltages are used on our test equipment to replicate the conditions the injector was designed to operate under. Our process restores the crystal stack to its original dimensions and performance.

Injector-Rehab’s Rebuilding Process

We are able to regenerate the piezo stack back to OEM Specs. In working with the injector manufactures, we have an operating plan for every Piezoelectric GDI injector ever made. This operating plan is executed as designed by the original manufacture to the specs it would be as NEW. This is not something that can be done by any company using a standard port injection machine. This process requires highly technical, rare and expensive equipment. Injector-Rehab is equipped with the proper equipment to test and refurbish. Unlike most other companies claiming to be able to rebuild a Piezoelectric fuel injector, we actually can. Sending your injectors to a company using a standard port injection machine is the equivalent of taking your car on the highway, opening the windows and throwing your money out.

Service for Piezoelectric Injectors can be purchased HERE.

GDI Spray Pattern
BMW N54 Piezo Injector