Engine Exhaust Solid Sub-23 nm Particles: II. Feasibility Study for Particle Number Measurement Systems

In the current vehicle exhaust legislation particle number (PN) limits for solid particles >23 nm are prescribed for diesel vehicles. The legislation was extended to include gasoline direct injection (G-DI) vehicles since 2014. Target of this paper was to investigate whether smaller <23 nm solid particles are emitted from engines in considerable concentration focusing on G-DI engines. The literature survey and the experimental investigation of 5 vehicles showed that engines emit solid sub-23 nm particles. The average percentage over a cycle (WLTP) is higher for G-DIs (<60%) compared to diesel engines (20%). These percentages are relatively low considering the emission limit levels (6x10^11 p/km) and the repeatability (10-20%) and reproducibility of the particle number method (50%). These percentages are close to the percentages expected theoretically not to be counted due to the 23 nm cut-off size (5-15%). High emissions can be found when additives are added in the fuel or lubricant. Based on the information today, the PN legislation should remain the same. However measurements of particles <23 nm should go on in order to monitor current and future technologies.

GIECHASKIEL Barouch;  MARTINI Giorgio; 

2014-11-17

SOCIETY OF AUTOMOTIVE ENGINEERS

JRC88729

1946-3952,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC88729,   

10.4271/2014-01-2832,