重型柴油车实际道路 NO_x排放分析方法研究

PEMS is used to conduct the real-world emission tests on six typical China-VI diesel vehicles. Based on the work-based MAW（China and the EU），NTE method（U. S. EPA）and 3B-MAW method（U. S. CARB），the real-world NO_x emission characteristics of heavy diesel vehicles are studied，and the characteristics and applicability of different analysis methods are discussed. The results show that the NO_x emission results based on the work-based MAW method can meet the regulatory requirements of China and the EU，but the NO_x emission compliance based on the NTE method and 3B-MAW method is uncertain. The low utilization of NO_x emission data leads to the inability of NTE method to effectively analyze the real-world NO_x emission characteristics. And the 3B-MAW method is worthy of reference for NO_x emission classification management. Cold-start NO_x emission accounts for 47.3%-80.7% of the PEMS test，and the cold-start NO_x emission of heavy-duty diesel vehicles should be paid at⁃ tention to. However，the current real-world NO_x emission analysis methods for heavy-duty vehicles in China，the EU and U. S. are unable to effectively evaluate cold-start NO_x emission. Therefore，the supervision of cold-start NO_x emission in the next stage of emission regulations should put forward the specific test cycle，analysis methods and emission limit，to effectively reduce the actual NO_x emission of heavy diesel vehicles.