What has improved engine technology to do with it?
Improved engine technology and fuel quality has thus created a new debate. “Ironically, particle control regulations may have made the situation worse,” points out Wexler, referring to increased nanoparticle emissions. Andreas Mayer, an engineering consultant based in Switzerland, does not quite agree. “Engine development does reduce the number of the larger particles but not increase the number of the smaller particles,” he says. He however admits that there is a problem. “As a consequence, however, the average size of particles emitted by newer engines is smaller than the average particle size emitted by older engines. This might become a problem because if you have a mix of larger and smaller particles, the smaller tend to agglomerate with the larger ones but if there are fewer particles, but all small, they tend to stay separate which could prove a higher health risk,” he says.
“Technical solutions aimed at reduction of total particle emissions do not necessarily result in concomitant reductions in fine particle emissions; in certain cases, the opposite effect is observed, resulting in increased emissions of fine particles,” points out Lidia Morawska of Queensland University of Technology and her co-authors in an article in the reputed journal Environmental Science and Technology. According to Daniel Greenbaum, president of the US-based Health Effects Institute, “There does appear to be a relationship between control technologies and emissions of nanoparticles.” When emissions from a 1991 diesel engine was compared to that of a 1998 diesel engine in a study conducted by institute, both run on very low sulphur diesel, the new engine showed dramatic increase in nanoparticle emissions. “Although the precise reason for that is not known, one of the contributing factors is likely that the reduction in particle mass gives the nanoparticles fewer large particles to combine with, and so they remain as nanoparticles,” he says. He is however optimistic about particulate traps. “The good news is that these more efficient engines, when combined with a particle filter, appear to all but eliminate the emission of nanoparticles as well as reducing the mass,” he points out.
“Engine technology plays a vital part. If the combustion chamber is well designed emission of the small particles is reduced,” says Lennart Erlandsson of Sweden-based AVL MTC, a research and development and vehicle testing com pany. “Diesel fuel quality is not always important since formation of particles is more related to engine technology,” he points out. According to Lennart, the recently launched petrol direct injection (GDI) engine produces a lot of particles
Related Content
- Motorization management for development: an integrated approach to improving vehicles for sustainable mobility
- World energy perspectives on e-mobility: closing the emissions gap
- Genetically engineered crops: experiences and prospects
- Engines and tires as technology areas for efficiency improvements for trucks and buses in India
- India energy scenarios 2047
- Budget 2013-2014: speech of P. Chidambaram, Minister of Finance