Engine Design Technologies (Re-power)


Engine design applies new technologies to existing diesel engine technology, in
order to reduce emission levels. Similar to the technology found in roadside applications
today, these technologies improve existing design concepts and make the combustion
process more efficient, thus reducing waste gases and the associated pollutants. To
implement these new engine technologies, (primarily controlled fuel injection and
exhaust gas recirculation), an existing engine must be completely rebuilt, or removed and
replaced, (‘re-powered’), by a new generation engine.



Controlled Fuel Injection employs a computer-controlled regulation of diesel
fuel flow to the combustion process. Operating under constantly changing load
requirements and respective fuel delivery needs, diesel engines typically experience an
oversupply of diesel fuel to compensate for increased load requirements. Due to the slow
response rates of mechanical fuel supply governing systems, it is typical that some fuel
quantities are not consumed, or only partially consumed, during the combustion process.
This results in increased NOx levels in the exhaust gases. By electronically regulating the
flow of fuel to the combustion camber, these excess fuel delivery quantities can be
significantly reduced, thus curbing NOx emissions.



Exhaust Gas Recirculation (EGR) is an effective NOx-reducing technology
currently available in modern marine diesel engines, in anticipation of the pending 2007
Tier II decreased emission threshold requirements. This technology involves the
recirculation of exhaust gases to the combustion chamber following the initial
combustion process; thus replacing intake oxygen and reducing combustion temperatures.
Current diesel engines, equipped with this technology, and operating in on-highway
applications, are experiencing decreases in NOx emissions by 20-30%, although the
lower combustion temperature results in a slightly higher PM count. Similar trends are
expected in marine applications as well.