Magnetic Fields (image) World Scientific Caption The position of a piston inside an engine cylinder can be measured with sub-mm accuracy by using external magnetic sensors and requiring no sensor components at all inside the cylinder. (a) Two axially spaced magnetic sensors are used. (b) The raw magnetic field signals measured by sensors 1 and 2 due to the piston's inherent magnetic field are shown (c) Position estimates from the magnetic sensor and comparison with a LVDT reference sensor are shown. (d) The system does not require pre-calibration and automatically computes algorithm parameters for each individual piston-cylinder combination. Credit Authors Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.