Upgrade of Wartsilas Two-Stroke Engine Portfolio to fulfil the Changing Marine Market Requirement
The current W(a)rtsil(a) two-stroke portfolio consists of engine-types; RT96C, RT84T-D, RT82C, RT82T, W-X82, RT68-D, RT58T-E, RT60C-B, RT50- D and RT48T-D as well as the newly-developed WX35, W-X40, W-X62, W-X72 and W-X92 engines. The RT-flex82T engine has been upgraded for modern requirements and is presented in the portfolio as the new W(a)rtsil(a) W-X82 engine for VLCC/VLOC (Very Large Crude/Ore Carriers) and Panamax container vessels. Introduction of the new engine-types W-X35 to W-X92 will be described in a separate paper. By the end of 2012 more than one thousand electronically-controlled W(a)rtsil(a) 2-stroke engines had been ordered. As these flex-engines now account for 100% orders placed and RTA engines are no longer popular, this confirms that the common-rail technology is highly attractive and well established. The trend of reduced ship’s service speeds in combination with lower shaft speeds and lower engine powers for engine new buildings requires a continuous upgrading of the existing engines in the portfolio. To cope with this trend, engines are configured at lower ratings to gain the lowest possible specific fuel consumptions and to achieve low EEDI (Energy Efficiency Design Index) numbers. Therefore, for example, the rating field of the W-X82 engine was enlarged and the power of the RT-flex58T-E engine has been increased by 4% in order to fulfil specific market requirements. Additionally, an ’RT-flex’ version of the RTA48T-D engine has been designed and released to meet the requests mainly of the Chinese market. Also, on the RT-flex50, an engine arrangement with the turbocharger at the aft end of the engine has been introduced. This paper also reports on the development of W(a)rtsil(a)’s RT-flex engines focusing on design improvements to increase their reliability and serviceability, and to reduce maintenance costs. Pulse Jet cylinder lubrication and FAST (Fuel Actuated Sac-less Technology) fuel valves have been introduced to gain lower cylinder oil feed rates, lower fuel oil consumptions and reduced emissions respectively. The first measurements with FAST fuel valves during shop tests on different bore sizes confirmed the potential of reduced fuel oil consumption over the whole engine load range. The first engine with this new technology entered service at the beginning of 2012. The above-mentioned major improvements will be introduced on all portfolio engine types step-bystep. W(a)rtsil(a) two-stroke engines can be equipped with the Intelligent Combustion Control (ICC) system which adjusts the peak firing pressure of the engine according to the given design criteria and automatically balances compression and firing pressures in all cylinders by selecting the injection timing and exhaust valve closing within the allowed operating range. The Waste Heat Recovery (WHR) system which has now been installed on many projects will also be described in the paper and the operational benefits will be reported. The second part of the paper will highlight the wide range of service experience gained with the different engines. From this service experience, the good engine performance and reliability as well as the attractiveness of the common-rail engines can be confirmed. The first RT82C and RT82T engines have exceeded four and three years of successful operation respectively. The total accumulated running time of one hundred engines at sea has reached more than 1,000,000 hours. Further, the first RT-flex48T-D engine passed its’ shoptest and was commissioned in May 2012. A thorough insight into the behaviour of RTA and RT-flex components will be given including information on fuel and servo oil pumps, as well as injection control units and a review of Piston-running results. Additionally, the excellent performance of crank train bearings will be mentioned. Broader service experience of FAST injectors will be available after the validation test at the beginning of 2013 and will be reported during the CIMAC Congress. Releasing this promising technology is an important milestone to reduce the greenhouse effect of low-speed marine engines.
Heinrich Brunner ean-Noel Constantin Beat Schumacher Dominik Schneiter
W(a)rtsil(a) Switzerland Ltd,Switzerland
国际会议
上海
英文
1-14
2013-05-13（万方平台首次上网日期，不代表论文的发表时间）