Eddy current for speed measurement

14.09.2008

Turbochargers are now an important component in automotive engines, both for fuel consumption and environmental reasons. The devices are not only present in diesel vehicles, but also increasingly in petrol engines. Aside from the angle of the guide vanes, the speed of the vanes on the turbine wheel is critical for optimum performance of the turbocharger. The rotation of the vanes needs to be measured on the face side. Due to increasing material stresses and speeds, titanium vanes are now being used more often, which presents a genuine challenge in terms of measurement technology.
Titanium is a very poor electrical conductor. Therefore, eddy current sensors cannot easily be used with this material With vane speeds varying from 200rpm up to 400,000rpm, it is extremely difficult to accurately measure these speeds. The turboSPEED sensor reliably measures at a maximum distance of 1.5mm from the vane at temperatures up to 235°C. The controller for test bench applications can be installed at a distance of up to 25 metres from the sensor.
A sensor with integrated ASIC electronics has been developed jointly with Hirschmann Automotive for highvolume production applications. This combines the outstanding technical performance of the Micro-Epsilon speed sensors with a cost-effective high volume production version.