Wärtsilä has received its 1000th order for its two-stroke low-speed diesel, electronically controlled, common-rail RT-flex engines.
This milestone was passed in August with the placing of an order for a seven-cylinder Wärtsilä RT-flex82T version B main engine. This engine will power an efficient Very Large Crude Carrier (VLCC) tanker being built for JX Tanker Company Limited, the Yokohama, Japan-based major tanker company.
The 310,000DWT vessel is being built at the IHI Marine United, Kure shipyard, and is scheduled for delivery in 2014. The engine will be manufactured by Diesel United (DU), a Wärtsilä licensee in Japan.
The newly upgraded Wärtsilä RT-flex82T version B engine is based on the RT-flex82T, which has accumulated more than 100 reference installations. The high stroke-to-bore ratio along with the RT-flex common-rail system in Wärtsilä two-stroke engines, provide exemplary performance. According to the company, "the highest flexibility of engine tuning possibilities makes it possible to achieve the lowest fuel oil consumption in all operational conditions for VLCCs."
The first Wärtsilä RT-flex common-rail two-stroke engine entered into service in 2001.
Wärtsilä RT-flex engines
Wärtsilä RT-flex engines have an electronically-controlled common-rail system instead of the usual mechanically-controlled fuel injection pumps and exhaust valve drives. According to Wärtsilä, the RT-flex engine technology enables "excellent fuel cost savings across the entire load range, including the part-load range. Thanks to the common-rail system, the optimum injection pressure, fuel injection timing and exhaust valve timing are selected at all engine loads or speeds, ensuring efficient combustion at all times, full-load or part-load."
Other advantages of this technology include stable low running speeds (in the range of 10-12% nominal speed), smokeless operation, and improved control of exhaust emissions. For cylinder lubrication, an oil feed rate of 0.6 g/kWh can be achieved.
The common-rail system provides excellent balance in the engine power developed between cylinders and between cycles, with precise injection timing and equalised thermal loads. This offers notable benefits to ship owners and operators as this leads to extended intervals between overhauls, and hence a reduction in maintenance costs.