ABB Turbocharging has introduced the Flexible integrated Turbocharging System for Two-Stroke Engines (FiTS2).
The new sequential turbocharging system allows maximum fuel savings for two-stroke engines at part and low load, and at the same time maintains the flexibility to go to full engine output immediately. This offers significant long-term economic benefits for vessel operators and charterers with potential for fuel savings of up to three per cent, depending on load profile. ABB's FiTS2 was presented during Marintec China last week.
Fuel and Emissions Reduction
FiTS2 has been developed in close collaboration with low-speed two-stroke engine designer, Winterthur Gas & Diesel Ltd. (WinGD), which has developed a special tuning for FiTS2.
The new technology enables two-stroke engine builders to offer more flexibility, increasing the potential for higher efficiency and lower operating costs for their customers. NOx emissions from engines fitted with FiTS2 will also remain within IMO Tier II limits. Additional abatement technologies like SCR or EGR can be used to comply with IMO Tier III NOx emissions and will not greatly affect the system while still delivering fuel saving benefits.
FiTS2 Workings
To optimise engine efficiency via improved turbocharging in low and part load, the engine runs in lower loads with only one turbocharger in operation, whereas at higher loads (typically above 50 to 60 per cent engine load) two turbochargers operate simultaneously. The same principle is applied for very large engines – with FiTS2 they will run with two turbochargers in lower loads and with all three turbochargers for higher load operation.
Cut out of one turbocharger for lower engine loads leads to higher scavenging air pressure, increasing the compression ratio and firing pressure optimised by special tuning of FiTS2. The result is enhanced engine efficiency and lower specific fuel consumption while remaining compliant with emission regulations.
Compact and Lean Design
The specially designed cut-off valves for the FiTS2 system are flow-optimised and integrated with the turbocharger casings, ensuring a compact and lean design. Furthermore, the valves can be operated rapidly and automatically under load, without interrupting operation of the engine up to full load.
Robust design and very wide compressor maps of ABB’s A100-L and A200-L turbocharger series allow switching under load without surging and there are no requirements for additional by-pass valves or pipework, making FiTS2 a simpler and relatively low-cost solution compared to any alternative.
Less Blower Maintenance
An additional benefit comes from the possibility to switch off the electrically-powered auxiliary blowers at 25 per cent engine load, instead of around 35 per cent load. This enables additional savings via reduced power consumption and less blower maintenance costs due to significantly fewer operating hours.
Watch a video about FiTS2 below.
Picture: The FiTS2 intelligent turbocharger system consists of two or more turbochargers of different specification or size.
