该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。This paper share the experience gained with the first generations of Tier II NOx compliant MAN B&W engines in the Costamare fleet. The paper tells how- and why combustion chamber Cold Corrosion re-appeared, how corrosive wear was controlled and how MAN Diesel & Turbo have reduced the corrosive level on the latest Tier II engines. The previous MAN B&W engines were known by having a very low corrosive level, needing very little alkali neutralisations from the cylinder oil. In cases where this was not respected and the engines instead over-lubricated, the result was sometimes scuffing of the cylinder liners and piston rings due to bore polish. To increase the safety margin against such over-additivation, the oil industry developed cylinder oils with a lower alkali level. These oils were known as mid-range cylinder oils and typically had an alkali level between 55BN and 60BN. MAN Diesel & Turbo have fulfilled prevailing Tier II legislation, i.e. a maximum NOx limit 14.4 g/kWh, among others by means of “2-stroke Miller Timing”. Basic ingredients are a high scavenge air pressure, late closing of the exhaust valve and part load optimisation.

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 The marine applications provide serious challenges to the propulsion system designer. While bollard pull performance, manoeuvrability, compactness and ease of installation remain critical matters, great attention needs to be drawn to energy efficiency, environmental performance. Especially energy efficiency remains the most important parameter, influencing the life cycle costs of the operator at the most and directly impacting the environmental performance of the vessel. The present paper gives emphasis on the effort of the propulsion system engineer to achieve the highest optimization. This requires not only the highest efficiency from the individual systems and components but mostly the most efficient system integration. Emphasis will be given at the propulsion system: ship hull design/ propulsion unit/ shafting/ electrical machinery/ main engine. Both the mechanical and the electrical systems integration are considered. Three main cases will be analysed with as target to demonstrate the importance of the integration of the mechanical and electrical systems: 1) Engine and propulsion unit integration for offshore support vessels (OSVs) and tugboats. These vessels require medium size azimuth thruster units and medium/ high speed reciprocating engines. For efficiency enhancement, hybrid propulsion is considered in combination with advanced electrical machinery. 2) Engine and propulsion unit integration for Anchor Handling Tug Supply vessels (AHTS) and fishery applications. These vessels require Controllable Pitch Propellers, two- speed gear boxes and medium speed reciprocating engines. The overall automation control system is of critical importance. 3) Engine and propulsion integration for offshore drilling vessels. These vessels require large steerable thruster units (under- water mountable and/ or retractable) with large reciprocating engines. Performance integration leads at optimal Dynamic Positioning performance and lowest energy consumption. In parallel, very long periods between unit overhaul are required.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Today various applications in the area of computer aided engineering (CAE) offer extensive possibilities for a structured design and development approach. More than ever there is a strong demand for seamless project execution across various disciplines both on- and offshore. In addition, competition forces companies active in product development to continuously rationalise their time-to-market. In order to be most efficient with design and development of new products it is not enough to have the right engineering software applications in place, it is rather a question of how these tools are integrated in the corresponding environment and how structured is the approach for uniform application by all parties involved. This paper aims at providing an insight into the approach of Winterthur Gas & Diesel Ltd. how design and development of a modern two-stroke marine engine is carried out with focus on the actual engineering tools and methods landscape.

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 The latest development of engines is mainly driven by performance targets, lifetime costs and rules or regulations regarding emissions. All these demands lead to new generations of engines with several new technologies. On the one hand gas engines show the trend to install two-stage turbocharging systems to use the benefit of the intercooling for better performance. On the other hand diesel engines have to include new engine technologies, like exhaust gas recirculation (EGR) or exhaust gas aftertreatment systems, to manage the trade-off between emissions and specific fuel oil consumption demands. Dual fuel engines, more or less a combination of both engine types, are characterized by much higher compressor pressure ratios for diesel mode in comparison to gas mode. This implies new challenges for the single-stage turbocharging due to the demands of pressure ratio more than 5.5 in combination with wide compressor maps for mode switching. In the majority of cases the effectiveness of all these new technologies depends on optimized or even customized turbocharger solutions. The product portfolio of KBB reflects these requirements of new engine generations. KBB offers a new designed compressor family for the well-accepted single-stage turbocharger series ST27 to fulfill the special requirements of these engines. In addition KBB has developed the two-stage turbocharger system K2B, which can currently achieve charging pressures of up to 10 bar. Since their launch in 2014, the K2B system is installed on several diesel and gas engines and has now passed a significant operation time to evaluate the system. The paper contents a brief report on test rig and field experience. Apart from the performance targets, it addresses in particular the high demands in terms of sealing and matching both stages on the large variety of customized turbocharging control systems. Furthermore, KBB is engaged in the development of EGR turbochargers for single- and two-stage turbocharged engines. Main challenge is the matching of the compressor and turbine design due to the untypical turbocharger operating conditions in a high-pressure EGR system. Additional requirements are high durability at EGR specific entry conditions with intake temperatures of up to 140 degrees Celsius and sufficient wear resistance against condensate and particle impact on compressor side. Conventionally designed exhaust-gas turbochargers require considerable redesign to achieve reasonable efficiencies under these particular conditions. Since the exhaust-gas enthalpy which is carried away via the EGR turbine due to mismatching is not available to build up the actual charge-air pressure, the influence on the system's efficiency cannot be ignored. For this, KBB designed the specially-adapted EGR turbocharger ERT20 as an effective way to bridge the pressure difference between the exhaust manifold and air receiver on large diesel engines under consideration of the overall system efficiency demands. Apart from maximum turbocharger efficiency, the focus is primarily on reasonable costs and an acceptable service life of the components. The paper describes selected steps of the development and first results from test rig.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Efforts to limit air pollution and especially harmful effects of sulfur emissions from ships lead to the creation of sulfur emission control areas (SECAs). One of these areas is the Baltic Sea. These areas and emission limits are defined in the Annex VI of the 1997 MARPOL protocol which came into effect in 2005. The Annex VI was later revised and the maximum allowed sulfur level in fuels used in the SECAs has since come down in two steps. The final step down from a maximum of 1.0 % to 0.1 % sulfur was taken in the beginning of 2015. Since then, the vessels operating in the Baltic Sea SECA have only been allowed to use fuels containing a maximum of 0.1 % sulfur or having to use an exhaust aftertreatment system to achieve an equivalent reduction in SOx emissions.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。During the last decades Natural Gas has been gaining more importance as fuel within the global energy mix. The main driver for this development is the good long term availability as well as the lower price of gas compared to other liquid fuels. In addition Natural Gas and Dual-Fuel engines are capable of providing robust and efficient engine solutions for the usage in mobile and stationary Large Engine applications. From technical perspective the achievement of high loads in conjunction with highest efficiencies and low tail-pipe emissions is within the centre point of today’s development goals for engine manufacturers. In order to meet these goals different combustion strategies can be used. Advanced technology concepts like the use of cylinder-individual fuel gas admission play a key-role to meet these requirements.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Kawasaki Heavy Industries, Ltd (KHI) developed Green Gas Engine KG series V-type gas engine for power generation plant in 2007. The world’s highest electrical efficiency and the lowest level NOx emission below 200ppm at 0% O2 were achieved at the same time. More than 70 sets of KG series gas engine have already been applied for power generation plants over the world and serving the high performance successfully. Recently the regulations for the prevention of air pollution from ships, seeking to minimize airborne emissions from ships (SOx, NOx, etc.), is coming into force. In such situation, KHI started the development of L30KG marine gas engine in 2011 based on the KG series for the purpose of applying marine applications. L30KG is designed as a line type engine to make maintenance work easy on board and is covering the power range of 2670 to 4005kW with 6, 8 and 9 cylinder engines.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。Selective catalytic reduction of NOx by urea (Urea-SCR) is a commercially proven and efficient technology to reduce NOx included in diesel engine exhaust. This technology has been widely applied to various marine vessels with 2-stroke diesel engine to meet the stringent air pollution regulations including IMO Tier III. In order to overcome the installation constraint of SCR system in the engine room, low pressure SCR (LP SCR) system which is installed at the downstream of the engine and turbochargers, especially in the funnel of the vessel has been developed. LP SCR system of 2-stroke engine is operated under low temperature condition at the temperature below 250 oC due to the loacation of the installation as described above. The effective decomposition of urea to NH3 as a reducing agent is important to achieve the required performance of the SCR catalyst, especially at low temperature condition of LP SCR system. In order to maximize the conversion of urea to NH3, a new urea decomposition chamber has been designed by using a urea decomposition catalyst in the present study.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。The third stage of emission limits for nitrogen oxides (Tier III) applies to new buildings when operating in an Emission Control Area (ECA) for vessels being keel-laid after January 2016. Particularly the SCR guideline by IMO, MEPC.198(62), and the herein introduced Scheme B approach imposes a strong challenge for engine and SCR manufacturers, ship operators and certifiers (Recognised Organisations / classification societies). Following this guideline a combined engine and SCR may be tested separately in cases where the combined system can neither be tested on a test bed due to technical and practical reasons nor an on board test can be performed fully complying with the test requirements detailed in the NOx Technical code 2008.

该论文已在赫尔辛基举行的第28届CIMAC大会上发表，论文的版权归CIMAC所有。A known issue with all gaseous-fueled engines, including dual-fuel engines, and especially those with fumigation-type or other “upstream” injection of gas, is poor transient response. This is due to the transport delay from the gaseous fuel injection point to the engine cylinders. This delay can result in slow up-transients as well as slow down-transients. We present a solution to the problem of poor up-transients (a request for increased torque from the driver) in the form of state-based diesel fueling. That is, matching the quantity, timing, pressure, and pattern of the diesel injection to the current in-cylinder state of the engine. In order to have state-based fueling knowledge of the state must be available. This is achieved via a natural gas fraction observer. That is, a model of the intake manifold natural gas to air ratio. Other important states include pressure, mass and/or concentration of oxygen, and temperature.