Drying of water vapor within exhaust gas and the effect of dryer on emissions

This is the purpose of the work to keep the water vapor in the exhaust gas with the appropriate drying method and to examine the impact of on the emissions. Thus emission devices used in engine tests will not be affected from humidity within exhaust gas and it will be avoided high maintenance and repair costs. The test system has been established with diesel engine used in Ford Transit minibus for thesis. Heat exchanger is designed using heat transfer formulas to dry the water steam, it has been integrated after the manufacture into measurement system. Thanks to the dryer design, provided the condensation of water steam in the sample gas, gas temperature is reduced from 110°C to 13°C, dangerous humidity of over 100% limit for emission devices is reduced to 80% range. When the end of test graphics examined, it was observed incorrect results about 40% on THC, NOx, CO2, CO and O2 emissions without dryer system. Over range of humidity measurement results are not reliable that limit humidity value located in the manual of emission measurement devices. Before measurement of samples of exhaust gas in extreme humidity conditions, relative humidity should be reduced within limits. In this case, drying of the exhaust gas is required before the emission measurement.