Research On The Distribution And The Influencing Factor Of The Stage 5 In-use Vechicles In China

The OBD(On Board Diagnostics)system as an important technical means of emission control is widely used in the current engine electronic control system.In order to guarantee the completion and frequence of the OBD,we require quantitative indicators to constraint the OBD,the IUPR(In-use Performance Ratio)embodies the quantitative indicators expressing the diagnosis frequency of a certain monitoring when the car is running.The requirements of IUPR are mentioned in China stage 5,but whether the IUPR can complete monitoring under the real road condition,the requirement can limit the monitoring of OBD system are barely researched.Therefore,by analyzing the monitoring theory of the IUPR,this thesis has carried on the related research,as followings:(1)Collected the IUPR information of 200 vehicles of China stage 5 in Beijing,lasted four months,obtain and analyze the distribution of the IUPR.(2)Analyzed the influence of the typical road conditions,driving habits and environmental temperature influence on the IUPR monitoring;(3)Verified the IUPR function under the NEDC,and compared the change rules between NEDC and the typical road conditions.The following conclusions have been reached:(1)The IUPR are between 0.69 and 1.9,which satisfied the regulations requirements of 0.1;(2)the change rules of the IUPR under different typical road are different,Some extremely conditions can cause the IUPR hardly completing monitoring;The driving differences between the change rules of the IUPR by different drivers are small,mainly manifested in the numerator;the temperature almost has no influence on IUPR.(3)The IUPR can complete monitoring under the revised NEDC,but hardly completing the monitoring under congested roads,so we recommended to use cycle satifhied the Chinese road condition to verify the IUPR test.