More haste, less speed
To the chagrin of marine engine manufacturers, it appears ships’ engineers are reluctant to embrace the common rail system with the same grade of enthusiasm as those of the makers of these engines.
the maintenance of common rail engines is labour intensive and parts are hugely expensive. So what is it about the common rail system that is proving to be more complex than expected? Regulations on nitrogen oxides, sulphur
E
oxides and smoke have tightened both regionally and internationally. Ships’ engines need to have the ability to maintain fuel injection pressures sufficiently high at all engine loads and speeds especially in pollution sensitive areas such as SOx Emission Control Areas (SECAs), and the ever expanding list of US ports that have
Naval, Commercial & Offshore ngineers claim that while the
common rail system works well in 4x4 vehicles, in marine applications
taken a leaf out of the books from the State of Alaska and are adopting stricter rules. In Alaska, smoke emissions for vessels calling at its ports have to be kept under 20% when alongside. In order to ensure ships comply fully with its regulations on smoke, the talents of visible emissions readers are utilised. These individuals are trained and
certified using a standardised national method known as the Ringleman’s chart. The method requires readers to visually differentiate the opacity of the emissions using a set of examples. While some dispute this is not an exact science, since a critical part of the reading requires the sun to be behind the reader in order to reduce light
scattering which makes the plume appear darker, heavy penalties can result if the state’s smoke emissions regulations are exceeded. Particulate generation in diesel engines
is a complex process. It represents a broad mixture of partially burned and unburned hydrocarbons, sulphates, ash and soot. At high loads, ash and soot might contribute less than 20% to the particulates, but at low service loads, especially during rapid start-up manoeuvres and load changes, the intake air the engine needs for complete combustion is less, and the engine ‘smokes’ since there is not enough remaining combustion time to burn away the soot formed. Smoke also occurs, when more fuel is injected than can be burned in the available air in the cylinder.
THE MAJOR CHALLENGE FOR THE SHIPBUILDING SUCCESS IS TO ACHIEVE MORE RELIABLE, PROFITABLE AND SOPHISTICATED VESSELS WITH VERY TIGHT COSTS IN LESS TIME
WITHFORAN At the forefront in shipbuilding engineering
AF_CampañaFORANV70-2012(132x175)
engOKOK.indd 1 The Naval Architect March 2012
THIS IS POSSIBLE
www.foran.es www.sener.es
26/02/12 20:30 27
Courtesy of La Naval Shipyard
Feature 1
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52