A heavy-duty engine is type-approved in engine dynamometers, while its in-service conformity is controlled on the road. In the first case, laboratory particle number systems (LABS) sample from a full dilution tunnel or a proportional partial flow dilution system (PFDS). In the second case the portable emissions measurements systems (PEMS) measure directly from the tailpipe. Permitting in the regulation the LABS sampling directly from the tailpipe would simplify testing and would improve their comparability with PEMS. In this study PEMS and LABS, both sampling from the tailpipe and measuring solid particles >10nm, were compared with references systems (i.e. LABS sampling from PFDS). One compressed natural gas (CNG) engine, and three diesel engines, all Euro VI step E, with or without the urea injection, and with or without the crankcase ventilation connected to the tailpipe, challenged the systems with different emission levels and particle sizes and properties. The results showed that the differences of the LABS to the references were within ±25% in most cases for the LABS, with a few exceptions. The PEMS were within ±50%. There was no or small effect on the differences from the engine technology, the urea injection or the crankcase ventilation. The urea injection increased the >10nm emissions 300-600%. Connecting the crankcase ventilation to the tailpipe further increased the >10nm particle number emissions 340-560%.

GIECHASKIEL Barouch;  SCHWELBERGER Matthias;  KRONLUND Linus;  DELACROIX Cristophe;  LOCKE Logan;  KHAN Yusuf;  JAKOBSSON Tobias;  OTSUKI Yoshinori;  GANDI Sawan;  KELLER Stefan;  GROB Benedikt;  DARDIOTIS Christos;  MAMAKOS Athanasios;  LU KARLSSON Hua; 

2022-08-19

ELSEVIER

JRC128654

2666-691X (online),   

https://www.sciencedirect.com/science/article/pii/S2666691X22000355?via%3Dihub,    https://publications.jrc.ec.europa.eu/repository/handle/JRC128654,   

10.1016/j.treng.2022.100137 (online),