A fuel flexible injection system is allowing WinGD to explore various liquid alternative fuels, WinGD General Manager, Technology Development, Andreas Schmid explains

Winterthur-based engine designer WinGD plans to use a new fuel-flexible injection (FFI) system to extend its research into a range of liquid alternative fuels, Andreas Schmid told The Motorship in a recent interview.

The FFI system was developed as part of Work Package 1 of the HERCULES 2 project (2016-2018). The HERCULES series of projects saw engine designers, universities and technology companies across Europe collaborate to advance the performance of large marine engines.

The FFI system itself represented an interesting solution to the technical challenges of handling fuels with differing calorific values and densities. The development of interest in alcohol fuels, such as ethanol or methanol, also raised different technical challenges: the low lubricity of methanol and ethanol would shorten the operational life of traditional injection components.

The solution features an adjustable needle with two different aperture settings, to allow for the injection to adapt for the liquid fuels’ calorific value.

The results of the research were presented by Andreas Schmid at the CIMAC conference in Vancouver in 2019. One of the results of the research was that ethanol combustion (with a small amount of diesel injected as a pilot fuel) reduces the formation of NOx and smoke emissions.

WinGD had extensive experience of other aspects of fuel injection. Spray morphology and combustion performance were assessed in WinGD’s Spray Combustion Chamber (SCC), an experimental rig which allows the effect of various nozzle designs to be observed by taking optical, pressure and temperature measurements.

“During our tests of ethanol, we identified some interesting effects we want to have a closer look at,” Schmid noted. The tool offered the possibility of insights into a range of fuels from an R&D perspective, Schmid noted. FFI could help WinGD develop a better understanding of the combustion properties of LPG, for example, “although backpressure issues would need to be addressed.”

WinGD had opted to conduct the HERCULES 2 tests in late 2018 on ethanol rather than methanol because ethanol posed fewer hazard challenges, but bio- or synthetic methanol represents an interesting low carbon fuel for the future, Schmid noted.

“There are availability issues at the moment and the fuel needs further development work. But when it comes to liquid fuels, it is one of the realistic alternatives further down the line.” In fact, one of the next fuels to be tested on WinGD’s RTX-6 test engine was likely to be methanol, Schmid noted.

WinGD is currently involved in several other projects investigating new liquid fuels, including the FALCON or the IDEALFUEL project to develop a carbon-neutral alternative to HSFO from lignin, an organic polymer found in the cell walls of many plants.

Commercial development

In its current form, the FFI was not intended to be offered as a solution for commercial engines but was intended to help WinGD to develop more tailored injection concepts.

“The fuel flexible system offers possibilities that you probably won’t need on a ship: nobody would be willing to pay for the possibility of switching between liquid fuels instantaneously.”

But the flexibility might be interesting for highly route specific or vessel-specific conditions, where shipowners might benefit from the ability to switch between fuels after bunkering, such as ethane carriers.

The Motorship notes that the development of a sophisticated multi-nozzle injection solution extends the fuel injection options for some liquid fuels, such as ethanol.

Such an approach could also be applied to some of the liquid alternative fuels that WinGD is examining, such as ammonia. Other engine designers that have conducted tests into ammonia have combined the fuel with LNG.

The development of more sophisticated multi-staged combustion strategies may also require the development of more rigorous control over fuel injection, The Motorship notes.

“The injection system is not the only, but the most challenging element of designing an engine for fuel flexibility,” Schmid noted.

Some of the other solutions were comparatively less interesting, Schmid noted. Emulsification of alcohols or even classic fuels with water was promising in terms of NOx compliance but would require aftertreatment to handle the CO2 emissions, depending on the source of the fuel.

“Our engines are already Tier III compliant, so this is not an immediate priority for us,” Schmid noted.

Andreas Schmid noted that the next steps for the research would be to carry out further investigations into how a future commercially viable fuel-flexible injection system could appear.

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