Abstract
With the ever so imminent threat of climate change caused by man-made pollution, IMO introduces a new piece of legislature: IMO Annex 6 Tier III regarding air pollution. To meet new standards of exhaust air content, engineers are scrambling to find new and efficient ways to keep the shipping industry going. With the dawn of two-stage turbocharging developing high values of inlet air pressure in combination with early IVC using variable valve actuation depending on the engine load, the regulations are met. In this study the effectiveness of the previously mentioned concepts are put to the test against the conventional Diesel cycle used on board most vessels today. A detailed comparison of the two is conducted followed by a thorough analysis and argumentation.
Highlights
With the introduction of Tier III MARPOL Annex 6 regarding Marine Air Pollution [1] which took effect for all new vessels constructed after 1st January 2016, strict regulations are introduced regarding NOx and SOx harmful gasses
With the dawn of two-stage turbocharging developing high values of inlet air pressure in combination with early IVC using variable valve actuation depending on the engine load, the regulations are met
NOx gases form at temperatures around 1200°C, but successfuly utilizing early IVC opens the possibility of near constant combustion temperatures during all engine operation loads and the prevention of unwanted gas contents in the exhaust
Summary
With the introduction of Tier III MARPOL Annex 6 regarding Marine Air Pollution [1] which took effect for all new vessels constructed after 1st January 2016, strict regulations are introduced regarding NOx and SOx harmful gasses. Among many other options that the engine manufacturers had to choose from, one of them was using Millers early IVC. The effect of early IVC is expansion and cooling of air in the cylinder which in turn lowers the cycles starting parameter values (pressure and temperature) causing the aforementioned parameters to decrease in value throughout the cycle. With the assumption that the expansion starting at the closing of the inlet valve (c) [5] and ending in BDC is completed adiabatically, follows: dU = –dL (1). Since work gained in an adiabatic expansion is solely at the cost of internal energy [3], the movement of the piston towards BDC, after inlet valve closure, produces work and cools the medium. Expanding equation (3) produces a relation between pressure, temperature and volume with which concrete effects of cooling and expansion of the air are noticed. With the intention of obtaining a more practical visualisation of data, a marine four-stroke diesel engine MAN L32-40 will be used as an example [6, 7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
