WinGD readies for ethanol as fuel

WinGD led the development of an ethanol-capable injector, observed combustion parameters on a test rig, and used ethanol in its full-scale RTX-6 laboratory test engine, as part of the EU-funded HERCULES-2 project.

This study showed that, on injection, methanol and ethanol are propagated into the combustion chamber faster than diesel, possibly due to their lower compressibility. On combustion, methanol and ethanol release heat faster and combustion chamber pressure peaks faster than diesel. The company observed that starting to inject ethanol just before the pilot fuel led to a more preferable combustion – with the highest pressure rise and shortest duration – than injecting diesel either before or much later than the ethanol.

With this new injection technique, it was found that the brake specific fuel consumption when operating the engine on ethanol was similar to that of diesel, once ethanol’s lower heating value had been compensated for. NOx emissions decreased slightly with ethanol due to the fuel’s high vaporisation heat, which means that the charge air is cooled as the fuel evaporates. Due to the lower temperature at combustion, less NOx is formed.

Reduced emissions

Smoke emissions also decreased significantly with ethanol fuel due to the oxygen within the ethanol molecule, which reduces the chance for rich zones (and therefore unburned fuel) and helps combustion of particulates, thus contributing to lower PM emissions. Additionally, the longer ignition delay of ethanol means that more of the fuel is evaporated and ready for combustion, further reducing the chances of fuel-rich zones.

“Having subsequently developed our methanol-fuelled X-DF-M engines, we can confirm that the combustion properties, performance and emissions characteristics of methanol and ethanol are comparable,” says Andreas Schmid, WinGD Strategic Marketing Manager. “The key difference is that ethanol has a higher lower heating value (LHV), translating to higher energy density. This means that the volume of ethanol injected into the engine needs to be around 25% less than for methanol to generate the same output.”

That difference entails changes to injection pressure and atomizer design, as well as some modifications to the control system. Regarding safety, the same provisions for methanol under the IMO’s IGF Code also apply to ethanol.

“Our ethanol engine progress is founded on dedicated fuel research as well as the successful development of our methanol engine,” says Schmid. “The X-DF-M engine has is performing well in its first applications, with fuel efficiency beyond that of single-fuel engines, low pilot fuel consumption, reliable operations, and a simple concept that has been well appreciated by operators using it and the class societies approving it.”

The remaining questions concern the business case. “For example, do owners need a methanol-optimised engine that can also use ethanol, or vice versa? Or do they need a separate engine design optimised for each fuel type?

“There is ready availability of ethanol as a byproduct of sugar cane production, for example, but this faces some regulatory challenges, as the EU will not count emission reductions from a biofuel that competes with food for land usage. Green ethanol production from renewable biomass sources, which do not compete on land use, are emerging although currently at small scale. And there are indications that the cost of green ethanol could initially be lower than the cost of green methanol.”

These are among the issues WinGD is discussing with shipowners, engine builders and fuel suppliers. “We will continue exploring them with an even wider group of stakeholders as part of our founding membership of the Global Ethanol Association. As clarity on the market and business case grows, we are confident in a rapid development process to an engine that has similar robust performance, efficiency and reliability as WinGD’s existing dual-fuel engine portfolio.”

WinGD methane fuel specifications independent of source

WinGD sets out specifications for methane fuel quality that can be used in its engines independent of its source. It is therefore similar for fossil, biomass-derived or synthetic variants.

Several users of WinGD X-DF engines have already adopted bioLNG without any impact on performance or reliability. This experience goes across our engine bore size range, from an ultra large container ship operator running on a 20% bio-methane blend to a pure car and truck carrier operator, NYK, which has been running our small-bore engines continuously on a bio-methane blend since June.