Apart from the angle of the guide vanes, the speed of the vanes on the turbine wheel is important for the performance of the turbocharger. The rotation of the vanes is measured on the face side for this. Due to increasing material stresses and speeds besides aluminium, titanium vanes are now being used, which presents a challenge in terms of measurement technology.
Titanium is a very poor electrical conductor. Therefore, eddy current sensors cannot be used easily on titanium. With varying speeds from 200 to 400,000 rpm, it is extremely difficult to measure these precisely. However, using special linearisation and an advanced electronics system, Micro-Epsilon is able to precisely measure this speed on aluminium and titan vanes over the whole speed range.