Technology group Wärtsilä is offering an upgrading solution for its FuelFlex Injection Control Unit (ICU) to meet the requirements of operating its RT-flex type two-stroke diesel engines with both residual and low-viscosity marine fuels. The solution is available for retrofitting on vessels with Wärtsilä RT-flex96C-B and RT-flex84T-D two-stroke engines, and is expected to reduce premature wear to the ICU sealing area arising from the switch to lower viscosity, low sulphur fuels.
ICUs deliver a precisely controlled quantity of fuel into the cylinder at timed intervals, thereby ensuring efficient combustion at any engine load. The accuracy of the fuel metering and injection timing can be affected by leakages in the piston and valves within the ICU, with the fuel viscosity, pressure differential and clearances having an impact on the amount of leakage. The upgraded Wärtsilä Injection Control Unit is designed to address such issues.
Earlier generation ICUs were designed for continuous operation with residual fuels, and their long-term use with mainly low-viscosity fuels may result in shorter component life. The new FuelFlex ICU features a robust design with more durable materials and other improvement features providing better resistance against fuel leakage, while maintaining the designed service life expectancy of the component.
Based on Wärtsilä’s third-generation ICU, the solution features improved materials, a wider seal surface and a simple filling mechanism with improved leakage performance. The interface with the high-pressure pipe has been re-engineered with a spherical shape to limit plastic deformation. The design is also expected to optimise maintenance costs, as wear parts can be replaced by crew members on board.
“The latest FuelFlex ICU is a retrofit solution for customers that will increase both the reliability and environmental sustainability of their two-stroke engines. It also enables more flexible onboard maintenance of the unit, and the validation tests carried out have been very successful,” says Jung Yong Park, Product Manager, 2-Stroke & Specialized Services, Wärtsilä Marine.