FLOW INVESTIGATIONS WITHIN A CONCENTRIC CYLINDERS OF GAS SENSOR MODULE FOR I.C. ENGINES

For the global warming issues such as the reduction of greenhouse gas emissions, the exhaust gas from the internal combustion engines must be strictly controlled and purified by means of the catalytic convertor. The present investigation deal with the optical visualization of the flow field around the Zirconium sensors that is protected with concentric double cylinders with opening apertures. The commercial gas sensor modules were used for the monitoring of the Oxygen concentration before and after the catalytic convertor in passenger vehicles. In the experiment, a transparent acrylic model was used in conjunction with the particle image velocimetry as the velocimetry. The experimental result demonstrated that the magnitude of velocity in the vicinity of the sensor rod was significantly lower than that of the external main flow. The higher velocity fluctuation through the opening apertures contributes to the better mass transfer between the inside and outside of the protectors and enhances the response of the sensing module.