Abstract
Research and/or Engineering Questions/Objective
China has required IUPR in stage 5b emission standard GB 18352.5-2013, and in this year many types of LDVs has switched to this new version for several megacities. The objective of this study was to investigate the validity of in-use vehicles’ IUPR, especially focus on the relation between General Denominator increase action and vehicle operation condition in their daily running.
Methodology
CATARC’s Automotive Testing and Research Institute in Tianjin had carried out a large number of vehicles tests in real-world running conditions through OBD III equipment mounted on the vehicles, while the vehicles kept on their routine. Speed, general denominator and other signals of each vehicle are uploaded to data base in real time through Cellular Network. Earlier analysis of these data has resulted in sets of overall evaluation of IUPR in Tianjin city, and verification of the mechanism for general denominator for autumn running. EVAP IUPR for several vehicles was also investigated in this study.
Results
In the paper incensement of general denominator counter of many types of vehicles in autumn Tianjin was found to be in accordance to the requirement in standard GB 18352.5-2013, which was a positive evidence to confirm the compliance of these vehicle types to the denominator specification. Most vehicle samples showed that their IUPR rate for each monitor is greater than 0.1, showing that they are compatible to the jam traffic condition in China megacities for contemporary threshold. EVAP IUPR for several vehicles was greater than 1.0, which was a score by far greatly exceeding the threshold accordingly.
Limitations of this study
An important limitation of the current study is the limited temperature range in the environment, so as unable to reveal whether some vehicle will not be accordance to the standard in cold temperature such as around -7 ℃ . Furthermore, the verification for numerators for in-use automobiles, another key parameter for IUPR, was till a task to be fulfilled in later.
What does the paper offer that is new in the field including in comparison to other work by the authors?
The OBD III system enabled a method to acquire data from a daily use vehicle, which operates as routine on real road and encounters random running conditions, the activity about IUPR and general denominator revealed the vehicle’s genuine mechanism. A verification derived from this method will be of stronger authority than traditional verification solutions in labs.
Conclusions
A new method to verify IUPR is forward in this article, and the verification on IUPR and general denominator about LDVs in China is positive.
Key Words : IUPR; LDV; OBD; General Denominator