First Steps towards a Super-Compact in-situ Laser-Induced-Incandescence Sensor System

Abstract

To realize an actual in-situ Laser-Induced Incandescence (LII) sensor system for measurements in an exhaust pipe of a combustion engine, suitable components for such an application were chosen, integrated in a first prototype and tested. Key components for the proposed LII system are a super-compact high-power DPSS laser (CTR HiPoLas®) as excitation source, fast KETEK silicon photomultipliers (SiPM) as detectors and a specially designed optical measurement setup. Using a defined aerosol from a soot generator (Jing 5201 miniCAST), signals were collected at different laser energies and soot concentrations. By comparing the recorded behaviour with the literature, the incandescence effect could be reliably identified as the true source of the signal. Further long-term tests at an AVL engine testbed were performed.