The effect of cylinder liner operating temperature on frictional loss and engine emissions in piston ring conjunction
journal contributionposted on 03.03.2017, 13:41 by Ramin RahmaniRamin Rahmani, Homer Rahnejat, Brian Fitzsimons, D. Dowson
Despite extensive research into alternative methods, the internal combustion engine is expected to remain as the primary source of vehicular propulsion for the foreseeable future. There are still significant opportunities for improving fuel efficiency, thus directly reducing the harmful emissions. Consequently, mitigation of thermal and frictional losses has gradually become a priority. The piston-cylinder system accounts for the major share of all the losses as well as emissions. Therefore, the need for an integrated approach, particularly of a predictive nature is essential. This paper addresses this issue, particularly the role of cylinder liner temperature, which affects both thermal and frictional performance of the piston-cylinder system. The study focuses on the top compression ring whose critical sealing function makes it a major source of frictional power loss and a critical component in guarding against further blow-by of harmful gasses. Such an integrated approach has not hitherto been reported in literature. The study shows that the cylinder liner temperature is critical in mitigating power loss as well as reducing Hydrocarbon (HC) and Nitrogen Oxide (NOx) emissions from the compression ring – cylinder liner conjunction. The results imply the existence of an optimum range for liner working temperature, independent of engine speed (at least in the studied cases) to minimise frictional losses. Combined with the study of NOx and HC emissions, the control of liner temperature can help to mitigate frictional power loss and reduce emissions.
The authors would like to express their gratitude to the Engineering and Physical Sciences Research Council (EPSRC) for the Fig. 19. Percentage average reduction in thermal losses in the power stroke for 10 C gradual increase in liner temperature. R. Rahmani et al. / Applied Energy 191 (2017) 568–581 579 funding of the Encyclopaedic Program Grant (www.Encyclopaedic. org), under which this research is carried out in collaboration with a consortium of industry and academic institutions. Thanks are particularly due to Aston Martin for financial and technical support of this research.
- Mechanical, Electrical and Manufacturing Engineering