Feature 2 | MEDIUM-SPEED ENGINES
Unerring quest to optimise combustion
process
The development of medium-speed engines is driven by a current
market-wide goal to increase efficiency and reduce emissions. Intensified
research and a more holistic approach to powering requirements at ship
design stage are influencing the sector, according to David Tinsley.
A
gainst the backcloth of a weakened
global market and further
rationalisation of European
marine engine production capacity, with its
particular representation in the medium-
speed category, the main technological
strongholds are ploughing more resources
into knowledge advancement.
At the same time, designers and
MAN V28/33D
manufacturers are looking to extend the
Tier II engine
market reach of medium-speed plants, a
(Credit: MAN
process that is yielding ever-closer attention
Diesel).
to cost competitiveness and to the preparation
of innovative new powering solutions.
The German federal government has
n
e
provided funding for two phases of the
a
r
i
Emission Minimisation (EMI MINI) research and predict the combustion processes of and multiple injections. /
m
project. The first phase ran from 2002 to 2005. MaK marine engines. While a level of emissions equivalent to
o
m
One of the most important results was to The simulation demonstrated the influence IMO II with 30% less NOx has consequently
help lay the foundation for Caterpillar’s MaK of the nozzle flow on spray propagation and been achieved, it was apparent that NOx
t
u
r
b
o
.
c
Low Emission Engine (LEE) technology. droplet break-up. It also allowed the chemical values of 50% below IMO I were not o
i
t
h
.
v
The follow-on, second phase ran from 2006 and physical processes inside the engine to obtainable without some penalty in terms w
w
to 2009. Phase 2 had the clear objective of be viewed, which cannot be achieved with of efficiency. Therefore, to reach the given w
reducing medium-speed engine emissions current measurement techniques. target of EMI MINI II, it was found that
beyond IMO Tier II requirements and The results of spray investigation and additional research would be required. The
addressing future IMO III standards. simulation have led to improvements in the parties to the first and second phases of EMI
One of the key elements of the second single-circuit common rail system used on MINI accordingly agreed to pursue further
phase of EMI MINI has involved studies MaK marine engines. L’Orange optimised investigations under the aegis of the Fuel Dr. Dirk Jürgens, Head of Research and Development,
to optimise the Caterpillar Common Rail the design of the electronically controlled Air Management for Emissions Reduction
Voith Turbo Schneider Propulsion
(CCR) system to allow for MaK medium- injectors. Special emphasis was placed on (FAME) project, implemented in late 2009.
speed engine emission levels 50% below multiple injection capabilities as an essential The EMI MINI results and the present
IMO I requirements. requirement for future emission reduction. MaK LEE production engine guarantee
The future of propulsion. That’s what moves us.
Caterpillar’s research partners have Further tests with different rail pressures, the future of the MaK medium-speed,
included AVL Deutschland, L’Orange, WTZ injection parameters, compression ratios, long-stroke design philosophy, according to
Safety and precise maneuvering on Voith Turbo Marine offers tailor-made
Rosslau and the University of Rostock. and charge air temperatures took place Caterpillar, which has expressed confidence
the seas, lakes, rivers, waterways and propulsion systems for a wide variety of
The University of Rostock contributed at WTZ Rosslau, using a single-cylinder that suitable ways will be found to cope with
har bors of the world is of maximum applications – for harbor assistance
a detailed investigation of injection spray research engine. Investigations showed ever-more stringent emission edicts. In the
impor tance. Safe and eco-friendly drive and escort duties, ferries, supply- and
parameters on a special test bench. This that a 50% reduction in NOx (nitrogen meantime, in addition to its application to
sys tems are an essential prerequisite special vessels for the oil industry, for
provided data on how to optimise injection oxides) relative to IMO I levels would be new production engines, LEE technology can
for this. For over 80 years, Voith has military applications and for special ships
components for different fuel qualities. These attainable, with only a slight increase in fuel be retrofitted to all in-service installations of
been designing systems that are safe and individually configured mega yachts.
findings were also used by AVL to develop, consumption and smoke, by combining the latest generation of MaK medium-speed
for people and the environment.
improve and verify calculation models in certain NOx reduction measures with diesels, namely the M20C, M25C, M32C
the company’s CFD-FIRE software, enabling common rail capabilities, such as variable and M43C types.
Caterpillar Motoren of Germany to calculate injection pressure, variable injection timing Another development from Caterpillar’s
30 Ship & Boat International March/April 2010
SBI_MarApr10_p30-31-32-33.indd 30 26/02/2010 12:13:36
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