Analysis And Design Of The General Vehicle Exhaust Measuring Apparatus

With the rapid development of the social economy, the automobile industry has been growingvigorously, and the vehicle production is increasing constantly, which lead to many serious pollutionproblems caused by exhaust emissions. This, however, threatens the human health and ecological balance.In order to reduce the air pollution and improve the ecological environment, many countries and regionshave launched a series of stringent policies to control the emissions, as well as the related research.This thesis firstly introduces exhaust emission standards at home and abroad, and describes thestate-of-the-art devices and the trends for measuring exhausts. Then it studies the ingredients in theemissions, together with its testing principles and approaches. Taking the fact that the low integration of thevehicle exhaust detection into consideration, this thesis proposes to combine the exhaustconcentration measurement with the opacity measurement. In which, the former is based on NDIR (NonDispersive Infra Red) to detect the concentration of the exhaust emissions including carbon monoxide (CO),carbon dioxide (CO2) and hydrocarbons (HC), and on the electrochemical principle to detect oxygen (O2)and nitrogen oxides (NOx). The latter measures the exhaust opacity N and the optical absorption coefficientK with the principle of transmittance attenuation rate.Our detection system enables the human-computer interaction with LCD and key operations. Theinterface is implemented by the graphical user system μcGUI, which makes the interface simple, intuitiveand highly operable. This thesis discusses the architecture and platform transplantation of μcGUI.In terms of data processing, it provides data acquisition, data analysis, data query, print, and deleteand so on. Meanwhile, we designed the communication command and control code based on RS232between the PC and exhaust equipment, which shows and controls the results on the powerful hostcomputers.Our designed exhaust measuring apparatus enjoys a couple of advantages, including low cost,generality, stable performance and high accuracy.