The first of the latest Wartsila RT-flex82C common-rail marine engine type developed by Wartsila has successfully completed its official shop test on 17 September 2008 at Hyundai Heavy Industries Co Ltd in Korea, which is a licensee of Wartsila.
The seven-cylinder engine has a maximum continuous power of 31,640 kW at 102 rpm. It will be installed in a 3600 TEU container ship being built by Hanjin Heavy Industries & Construction Co Ltd of Korea.
The RT-flex82C is one of four new engine types all of 820 mm cylinder bore. They are designed to be ideal prime movers for a variety of ship types, including Panamax-sized container ships, typically up to 5000 TEU capacity, and large tankers, namely VLCCs and ULCCs of 200,000 dwt to more than 350,000 dwt, as well as very large bulk, ore and combination carriers.
Comprehensive test programme
The Wartsila seven-cylinder RT-flex82C engine at Hyundai has undertaken a series of tests as part of a comprehensive testing programme.
Three other engines of the 820 mm-bore type with an eight-cylinder configuration have also been manufactured by Hyundai and tested between April and September. The third of these eight-cylinder RTA82C engines successfully completed a type approval test on 11 September 2008 as representative of the RT-flex82C and RTA82C engine types. The type approval test was witnessed by representatives of all the major classification societies.
The performance of both RT-flex82C and RTA82C engine types fully met all expectations and predictions. Throughout the tests with the four engines all the measured results were in keeping with the calculated values and well within accepted limits. The measured parameters included stresses, strains, temperatures and vibrations in the engine structures, running gears and combustion chamber components, together with the pressures and temperatures in the engine processes, as well as fuel consumption, exhaust gas emissions and smoke.
Both RT-flex82C and RTA82C readily achieved the predicted brake specific fuel consumption (BSFC) of 169g/kWh, within the usual 5% margin. However, Delta Tuning which is only available with RT-flex engines enabled the RT-flex82C to reach significantly lower BSFC figures than the RTA82C in the part-load operating range.
The engines also readily complied with the specified NOX emission level in Annex VI of the MARPOL 73/78 convention, known as IMO Tier I. The engines were tuned to give a NOX emission level of 15.5 g/kWh to be safely below the specified level of 17 g/kWh. The smoke levels of the engines confirmed the benefit of smoke-free operation from the RT-flex82C, especially at low speed.
Tests were also undertaken with the seven-cylinder RT-flex82C engine to investigate further reduction of NOX emissions to comply with the IMO Tier II level of 14.4 g/kWh at the engine's running speed. The results were very positive, indicating that RT-flex82C engines can be built to comply with the expected IMO Tier II emissions control regulations.
A common platform for four engine types
The RT-flex82C is one of four new 820 mm-bore low-speed marine engine types developed by Wartsila. With two piston strokes, they have been developed on the basis of a common platform and sharing as many parts as possible to bring benefits of rationalization in the design and manufacturing, lowering manufacturing costs, and rationalizing also spare parts stocks.
Introduced in 2005, the four engines types are the RT-flex82C, RTA82C, RT-flex82T and RTA82T. With six to 12 cylinders, the '-C' versions cover a power range of 21,720 kW to 54,240 kW output, while the '-T' versions have six to nine cylinders for a power range of 21,720 kW to 40,680 kW. The two versions allow an optimum choice of engine to match individual ship requirements. The longer stroke of the '-T' versions enables lower running speeds.
The new Wartsila RT-flex82C and RT-flex82T engine types bring the benefits of both the electronically-controlled RT-flex common-rail system and up-to-date parameters to deliver optimum propulsion plants for the envisaged ship types. The RTA versions are available for those ship owners preferring traditional mechanical control. The RT-flex common-rail technology brings direct benefits to ship owners in terms of great flexibility in engine setting for lower fuel consumption, lower minimum running speeds, smokeless operation at all running speeds, and better control of other exhaust emissions. The RT-flex common-rail technology will also play a key role in meeting the need for tighter emissions control under the forthcoming IMO regulations.