Thermal Conductivity Sensors in Automotive Applications

Over the last decade, there has been a growing research interest in the on-board fuel generated hydrogen in automotive application. In this thesis, in order to find a suitable sensor to work in a complex gas mixture, currently commercialized hydrogen sensors have been compared. Furthermore, a thermal conductivity sensor has been selected and studied. The concentrations of hydrogen, nitrogen and carbon monoxide gas mixtures were simulated in Matlab. Simulation results demonstrate that the thermal conductivity of the gas mixture is measurable. Carbon monoxide, which is as a main interference gas to the hydrogen detection, does not influence the detecting. Moreover, experiments have also been conducted by using thermal conductivity sensor, bottled hydrogen, carbon monoxide and nitrogen gas mixtures. Up to 7 liter-per-minute gas flows and zero drift were tested in these experiments. The results obtained from these experiments are very similar to that of the simulation