The big news for the future of marine diesels seems to be 'more of the same', but in a continually deepening shade of green. Benefiting from, and building on technology developed for the land transport applications, major advances in fuel efficiency and emissions reduction have been achieved.
This was necessary in marine applications to meet the International Maritime Organization (IMO) Tier I and II standards (at sea), the requirements of the California Air Resources Board (CARB) Level 3 requirements (on the lower-west coast of the US), and the US Environmental Protection Agency (EPA) Tier 3 standards (within the US and its coastal waters).
The specifics to improve the compliance of some engines and to bring other models into initial compliance will include more turbocharging and higher injector pressures, but the biggest effects will result from improvements to the controls that will define each engine's performance map at various speed and loading combinations.
A performance map that more closely matches the required power in any situation will send just the right amount of fuel and air at just the right time. This will mean less wasted fuel, and that translates to a lower carbon footprint and cleaner emissions, and better economics of operation a positive result all around.
Further advances along the same lines are anticipated in meeting the more stringent standards of IMO Tier III, but full compliance may require additional measures such as exhaust gas recirculation, water induction or catalytic reduction to achieve the necessary reduction in nitrous oxides (NOx).
Owners and crew should be aware that under the NOx Technical Code, it is they and not the engine builders who are responsible for operational compliance.
Northern Lights DECS
Colin Puckett, marketing director for Northern Lights, says his company's Diesel Exhaust Cleaning System (DECS) is CARB Level 3 verified and NO2 compliant. Each system is based on MARINE-X diesel particulate filters from DCL.
DECS is custom engineered to match a vessel's generator set and specific engine room arrangement. With this system, the exhaust gas flows through a catalytically coated ceramic filter, trapping and burning soot (particulate matter, or PM, in regulatory language). DECS uses a passive regeneration process that requires little to no operator attention, and does not require additional fuel to burn the soot, thus improving fuel economy.
The goal of Northern Lights, Puckett says, is 'making sure your martini stays cold and your bikini stays white'.
Caterpillar and MTU
Caterpillar has installed two EPA Tier 3 compliant CAT engines on a new tugboat that will be operating in the ports of Long Beach and Los Angeles, California.
The company will be cooperating in a field follow-up study of the installation to monitor the reduction of NOx emissions.
It has also developed Dynamic Gas Blending kits for new and existing generator engines to provide a dual-fuel capability in applications where gaseous fuels are available. But because of supply infrastructure and on-board storage issues, the use of such fuels is well into the future for yachts.
Engine builder MTU has partnered with one of their major shareholders, Rolls-Royce, in supplying MTU 16V 4000 engine, propeller, rudder and automation packages to operators in Brazil and Norway.
Building on the success of these installations, the companies anticipate further cooperation in the marine propulsion field moving forward.
Steady-as-she-goes appears to be the foreseeable future of diesel power, but with supplies and costs of fuel ever shifting in unexpected directions, much research into alternatives continues to be carried out. None, however, would appear to be viable for the yacht market at the moment, so ever-evolving diesel it is.
Originally published: Superyacht Owners' Guide to Propulsion 2012.