Advanced Injection System by Means of Sensor Actuator Function

At present, diesel injection systems in automobiles with piezo element drives are replacing solenoid types due to their faster electro-mechanical properties. Their better fuel dosing characteristics offer lower fuel consumption, reduced noise and lower emissions. The limited elongation of the applied piezo elements within some tenth of micrometers makes these systems sensitive against mechanical tolerances, thermal effects and wear-out. Using the piezo element both as an actuator and as a sensor for the elongation and force allows an insight into the injector. The performance of this actuator-sensor behavior is shown together with a self-compensating loop for idle lift drift and a minimum fuel dosing control.