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。ABSTRACT Because of global warming and increasing air pollution, alternative fuels are increasingly being considered for use in internal combustion engines (ICEs). Among the alternatives, alcohol fuels seem very interesting. They can be produced in a renewable way and possess certain advantageous properties that give them the potential to lower pollutants and CO2 emissions from ICEs. Methanol and ethanol are the most researched alcohols today. In fact, in some areas of the world, gasoline is blended with methanol or ethanol for use in spark ignition (SI) engines. These alcohols are ideally suited for SI engines because of their high octane number (low tendency to knock). That makes them, however, not very well suited for compression ignition (CI) engines which require high cetane number fuels. There exist, however, CI engine technologies that burn alcohol fuels. One of these technologies is Dual Fuel (DF) operation. In DF operation, the engine runs effectively on two fuels. There exist several concepts to achieve this. One of these is to inject a mixture of diesel and alcohol fuel directly into the cylinder. Another is to separately inject diesel and alcohol fuel directly into the cylinder. A third concept (so-called fumigation) is to inject the alcohol fuel into the intake and the diesel directly into the cylinder (the homogeneous alcohol-air mixture is then ignited by a pilot injection of diesel). The paper will provide an overview of the literature regarding this fumigation concept. This work has been carried out as a part of the LeanShips project. LeanShips stands for ‘Low Energy And Near-tozero emission Ships’. It is a Horizon 2020 (H2020) project funded by the European Commission aimed at developing green shipping technologies and bringing these to the market. One of the Work Packages of the LeanShips project, ‘Demonstrating the Potential of Methanol as an Alternative Fuel’ aims to demonstrate a high-speed heavy-duty marine diesel engine converted to Dual Fuel (DF) operation on methanol (and diesel) while achieving significant reductions of emitted pollutants.

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。ABSTRACT Large container vessels utilize only about 50 % of the fuel energy content for useful work. The rest of the energy is lost to various kinds of heat losses. Majority of the heat loss is in the exhaust gas in form of thermal and kinetic energy. ABB has developed a Power Turbine Generator (PTG) Waste Heat Recovery System (WHRS) to capture part of the exhaust gas energy and generate electrical power out of the waste heat. The PTG WHRS system can capture about 4 % of the wasted energy, which means that it will increase the overall efficiency of the power plant by 2 % units. The WHRS system has been delivered to 14 container vessels which have about 47 MW main engines. The maximum power output of the PTG system was confirmed at sea trials to be around 1.6 MW as it was designed. The ABB PTG WHRS system can operate in parallel with auxiliary diesel generators, but also in island mode supplying all the electrical power to the whole ship. The PTG system has very low physical inertia and controlling the power turbine speed with a control valve that controls the exhaust gas flow to the PTG bypass line is very slow compared to the dynamics of the electrical network. Therefore the control of the PTG system in island mode is very challenging. The PTG system was developed together with ABB Marine and ABB Turbochargers, but before the pilot project, the full scale tests were not possible to do. The first full scale tests for the actual system could be executed in the last days of the first sea trial of the delivery project. This set a major challenge for the development as it was absolutely necessary that the automation and control works from day one. This paper describes the WHRS system, the basic principles of the control system, as well as the Hardware-In-Loop (HIL) development and test platform that was used to develop the automation and control of the PTG system. Quantifiable results of the improved development, delivery and on-site test process are given. Moreover, the performance of the control system onboard in island and parallel operation is demonstrated showing real measured data from a running implementation. As a result of the development project, the PTG WHRS system has been standardized so that the delivery of similar systems is very efficient.

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。ABSTRACT The marine and large diesel engine industry faces huge challenges regarding the significant reduction of harmful emissions. Over the past years, the contribution of shipping emissions to the overall emissions has increased, which brings ship engine emissions in the focus of a growing public debate. As a consequence of this public debate, efficient solutions for a significant reduction of particulate emissions could soon become necessary for certain engine applications. Cruise ships and ferries as well as vessels operated in sensitive regions (e.g. arctic waterways) feel the pressure for particulate filter installations in addition to the NOX and SOX abatement technologies which are required to comply with the IMO limits. Over the last decade, diesel particulate filters (DPF) have been successfully applied to nearly all on-road diesel engines (car and truck) and in many off-highway applications inside the EU. Significant reductions of PM emissions and impressive reliability levels have been obtained. Nevertheless, a successful transfer of the DPF technology to marine engines is still a huge challenge and requires ongoing research and development efforts. High ash loads, low exhaust gas temperatures and very low permissible pressure drops in the exhaust gas system are only some of the special challenges for DPF solutions in the maritime sector. These special requirements will be discussed in the first chapter of the paper. The paper then presents the findings of a comprehensive experimental project to obtain fundamental information on the particulate emission of medium speed diesel engines. The influence of fuel quality and engine load on the particulate emission was established. The test engine was operated with HFO, MDO and clean on-road diesel fuel (EN 590). Particulate emissions were sampled at different load points along the propeller and generator curves. Finally, the influence of increased injection pressure and increased injection flexibility was analysed using a CR injection system. The PM measurement equipment consisted of a Smart Sampler dilution tunnel for PM mass measurement, particle counter and particle sizer and a FSN measurement for comparison. Following the gravimetric analyses to determine PM mass, the loaded filters from the smart sampler were further analysed to determine the PM composition of organicsoluble, anorganic-soluble and soot components. For selected engine test points the PM emissions were further analysed regarding their reactivity which is considered as a parameter to describe the ignitability of the PM load in a DPF during filter regeneration. The reactivity analyses were carried out with an adapted thermo-gravimetric analysis procedure.

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。ABSTRACT Traditionally the ships have been desiged to one point and every system has been optimized to perform optimally in that particular point. However, the ships are very rarely operated in their design points. As a consequence of the single-point design optimization, the system level performance will be poor outside that point, meaning that the ship only rarely runs at optimal performance. Improvements in the systems which are in very low level in the energy conversion and transfer chain are intuitive and easily justifiable. For example, it is very easy to calculate the payback time for installing a Variable Speed Drive (VSD) for seawater cooling loop. When it comes to more complex systems, where different domains of energies are interacting with each other and systems have strong nonlinear interconnections and feedback loops, the efficiency improvements due to the technology improvements are not that easily justifiable for a human since the effects might not be intuitive for human comprehension. Therefore, in order to find the most beneficial results for the customer, it is important that the system level performance of the overall solution can be evaluated in the design phase, taking into account the assumed operation profile as well as the uncertainty of the assumptions. This paper proposes a method for using simulation to design optimal solution for the customer based on the actual operation profile. The method uses measured or estimated operation profiles and the Ship Energy Flow Simulator to calculate the optimal system level solution for a specific improvement, such as shaft generator, waste heat recovery system, etc. The proposed method takes into account the robustness of the solution, meaning that it can analyse the sensitivity of the Return Of Investment (ROI) time for the uncertainty in the assumed operation profile. Because the solution takes into account the uncertainty of the operation profile, the ROI time will most likely be reached in practice even though the operation profile of the ship would not be exactly the same as assumed in the design phase. The robust design method will be demonstrated using real measured data from a container vessel to design a shaft generator system for similar container vessel. The robustness of the ROI times are analysed with different sizes of the shaft generator and it is shown that if the uncertainty is not taken into account, one can end up in an investment which never pays back.

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。ABSTRACT The arctic areas are environmentally very sensitive from both the airborne emission and fuel spill point of views. Operating in the arctic climate puts high demands on the equipment since the range of the ambient temperature is very wide. The new, stricter, Sulphur Emission Controlled Area limitation came into force for Baltic Sea area in the beginning of 2015 and the NOx Emission Controlled Area limitations are coming .The Finnish transport agency ordered the first LNG powered icebreaker to be delivered in 2016 that needs to fulfill these requirements. Ice-breaking vessels have traditionally been powered by diesel engines, but the advantages of the gas-powered reciprocating engines have made gas an alternative also for the high demands of this application. There are several solutions to meet this requirement, i.e. exhaust scrubbers, using low-sulphur diesel oil or LNG. Low-sulphur diesel oil is technically an easy choice, but the global consumption increase of distillate fuel can be a cost issue in the future. By using gas as the main fuel for propulsion of ships in the region, the airborne emissions are significantly reduced and the risk for oil spill is minimized. The use of LNG is technically more challenging but seems to be more stable in terms of fuel cost compared to other solutions to reach the same emission levels. The worldwide availability of natural gas is good, and the infrastructure for bunkering gas is continuously expanding. The development of the natural gas price has been stable, and operating on gas will be an economically viable solution for decades to come. New ship layout solutions are needed to adopt the LNG system. For example, making the LNG supply as compact as possible will reduce the length of double-wall piping. The fuelling infrastructure must be arranged in a way that the storage tanks for LNG can be kept within a rational size but still allowing reasonable endurance. Fuel storage on board is calculated for ten days. The previous requirement means that the network of LNG terminals for refueling must be comprehensive enough. There are also challenges in introducing gas as fuel as LNG and gas engine applications are new. New guidelines are developed to maintain safe and reliable operation. The main part of the development process will be handled by Hazard Identification Study and Hazard Operational Study processes, i.e. by Risk Based Design, because there is not enough experience to write exact rules. The operation modes of an icebreaker cover the whole range of its power resources, and the main engine solution must allow the use of maximum power regardless of the fuel the engines are using. The change of fuel type must also be done without any power cut. The Wärtsilä dual-fuel engines can provide operational flexibility and safety needed by this application. Furthermore, they comply with stringent loading demands without smoke emissions as well as the IMO Tier III emission standard. The sulphur and CO2 emissions are also significantly lower for a gas-powered engine compared to a diesel engine of similar output. The Finnish icebreaker is using Wärtsilä 34DF engines as the main machinery and a Wärtsilä 20DF engine as the auxiliary engine because the solution was considered to meet the prime requirements for the icebreaker in all operational conditions. This Finnish icebreaker will be a very important future reference, e.g. for the arctic offshore supply vessels, when the emission requirements will become more stringent and, in general, the number of sulphur emission control areas will increase in the coming years.

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。ABSTRACT Abstract: Manufacturers of medium speed engines worldwide are faced with increasing challenges. The proliferation of natural gas, driven by advantageous fuel prices, emissions benefits and ready availability has driven the demand for sea transportation of the gas itself and for gas-fuelled marine engines. End users of the engines are demanding flexibility in the use of liquid or gaseous fuels while at the same time the engine manufacturers must commonise their products to reduce costs and increase competitiveness in an increasingly challenging market. Anqing CSSC Diesel Engine Co. Ltd (ACD) partnered with AVL List GmbH (AVL) to design a new spark ignited (SI) gas and a new Dual Fuel (DF) medium speed engine platform for marine propulsion applications. The engines were to use a common design as much as possible, with differences between the two kept to an absolute minimum necessitated by the combustion concepts: The SI-Gas Engine is a Pre-Chamber Spark Ignition (PCSI) concept. The Dual Fuel (DF) engine uses a Main Injector and a Micro Pilot Injector. This paper will describe the design approach used for the selected combustion concepts and the design methodology used to achieve a high degree of commonality between the SI-Gas and the DF engines. The SI-Gas engine was designed to be IMO III compliant. The dual fuel engine was designed to be IMO III emissions capable when operating in Gas mode and IMO II emissions capable when operating in Diesel (MDO, HFO) mode. The paper will discuss how a combination of thermodynamic calculations and existing engine development experience was used to determine the optimum engine performance and emissions architecture. The paper will describe key design elements of the new engine platform and the differentiating features between the SI-gas and DF engines will be discussed. Advanced CAE analysis were used in conjunction with the design of the engines to ensure the engines were optimised for functionality and operational efficiency. This approach will be described in some detail for the cylinder head design, where there was a challenging requirement to integrate the combinations of main and micro-pilot injectors and SI pre-chamber together with optimal port geometries and also maintaining sufficient structural strength and cooling. At the time of writing, the prototype engines were in the procurement & assembly phase therefore this paper will only focus on the design and analysis phase.

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。ABSTRACT The strategic decision by Wärtsilä around 2010 to develop a new medium-speed engine platform provided an opportunity to utilise new methodologies not so common in the world of large engine development but already applied in other industries since decades. From the outset, it was clear that a change in the way of working was a tool to create new values, not only for the benefit of the customer, but also for the overall product platform lifecycle management. This new programme demanded a cross-company, fully transparent development where R&D, Supply Management, Manufacturing, Sales, and Services collaborated closely from the very beginning and therefore became a showcase in requirement management, conceptual design, architectural studies, and several other front-end loaded methodologies. Requirement management is one crucial methodology applied. This aims to collect and understand market needs and treat these requirements in a controlled manner throughout the development. Extensive requirement gathering was successfully applied in the Wärtsilä 31 programme albeit with some unexpected outcome. Another important feature that even required an organisational unit of its own was the modularisation that, as the name implies, is an approach where the product is broken down into smaller independent entities, all with their own specific features and interfaces. Although past products have to some extent been modular in design, this brought the modular approach to another level. Modularisation is not only technical in nature but enables business strategies and customer values to be directly linked to the end product. Modularisation enables a flexible design that secures easy future development, and in the end, it has major implications for the product lifecycle process, the organisational setup, and the product cost and quality. Coupled with another strategic function, industrial design, the end result became significantly different compared to previous engine projects. Industrial design not only stands for branding and appearance but has its own value due to its direct link to conceptual layouts, usability, and product operation. Also, thanks to its visual capabilities, it is the key for the conceptual phase and provides a platform for communicating ideas and inspires innovations. The end result, Wärtsilä 31, is in many aspects strikingly different from previous engine development projects. In addition to the high performing engine design itself with all its new technologies, the way it has been put together, the sheer appearance and the way it is operated is a step change in the market.

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。ABSTRACT Gas as a fuel for merchant shipping has gained considerable interest during the last years, primarily driven by its inherent potential to reduce emissions, and secondarily due to the fact that gas is a sulphur free fuel, with the potential to be readily available at a feasible price. Winterthur Gas and Diesel Ltd. (WinGD) has developed a low-pressure Dual-Fuel technology for slow speed 2-stroke engines which is capable of meeting emission requirements far below the IMO Tier III limits, utilizing a low cost, highly efficient and reliable low pressure gas admission system. The basic concept was presented in the 2013 CIMAC conference in Shanghai and the technology is now implemented on several bore sizes in the Generation X-engine range and is taken into commercial use. The technology is based on the lean-burn Otto-cycle combustion process in order to exploit the full emission reduction potential of gas as a fuel and thus fully complying with IMO Tier III emission limits without any exhaust gas after treatment. Additionally, only low pressure gas supply to the engines is required, in contrary to the competing technologies. These advantages allow substantial simplifications on the plant installations, resulting in considerable savings of first time installation cost and very competitive operating cost. The first application of this technology was made on a 50cm bore engine type, where a number of engines have been produced and in service for some time. In the meantime, the Dual-Fuel technology has been developed and released for larger bore, lower speed engines like the X62DF and X72DF. A joint development project with WinGD’s Japanese licensee Diesel United Ltd. (DU) has resulted in the installation of a 6 cylinder X72DF test engine at DU’s Aioi works, and extensive testing has taken place, ensuring that the Dual-Fuel technology is fulfilling the market requirements. Preparations to extend the technology to even larger bore X engines have been taken. The present paper gives an overview of the concept and describes the application of the technology on larger bore engines. Besides an outline of the test bed setup, test results of the X72DF test engine are being presented. Additionally, a number of market references of 2-s Dual-Fuel engines are shown.

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。ABSTRACT Development of CR Technology In the last Decade – 4 Stroke Wartsila Engines. Mr. David Jay Mr. Arto Järvi Mr. Stefan Saario Mr. Diego Delneri Mr. Franco Cavressi The emissions regulations continue to tighten, from the 1st January 2015 ship owners needed to comply with options for the SECA (Sulphur Emission Control Areas). New IMO Tier 3 emission regulations are expected in 2016 in the ECA regions (North America & Canada). This new regulation requires NOx conformity at 4-5 selected load points on relevant emission cycles. With some coastal authorities imposing fines for visual smoke emissions this has driven engine fuel injection system designs into having more flexibility, greater fuel flexibility and additional extra effort in the lower load engine operation modes. In mid-2015, Wartsila has achieved over 3 Million hours from 14 cruise ships, 890 cylinders, operating with the W46 engines running first generation CR. This has been the basis and foundation for the reliability of the next CR generation equipment, called CR2. In detail, the paper describes how features of the CR1 equipment were developed, and validated, and later introduced for the CR2. System lifecycle cost experiences comparisons are presented for Wartsila W32 and W46 engines based on operator experiences. Performance has also advanced significantly in the last decade. The W20 engine has been used to pioneer the field testing on CR2 , multi-element pump systems, but the engine performance has progressed with a new 2200 bar concept injector design suitable with EGR, to reach the IMO Tier 3 regulations with a pure primary engine build. The new W31 engine has been an opportunity to design an engine purely for the future Common rail. This has enabled a smaller footprint, advanced valve train packaging, and compact engine block outline, with a smaller camshaft and drive train, due to the lower peak torques that are inherent of a high pressure jerk pump system. The merits of having a diesel engine version CR twin nozzle ,with a low load nozzle tuned for low load performance, with emphasis on smoke and emissions, and a high load nozzle optimised for full load efficiency has proven to be a performance pace-setter. The paper will also describe the functionality of the W31 DF Fuel injection equipment. The W31 fuel injection has a ‘one system fits all’ strategy, meaning the Dual fuel engine system also has a twin nozzle, with in this case the small nozzle optimised for the pilot fuel, to support gas ignition. The ‘one system fits all’ enables greater fuel flexibility, reliability, easy conversion and simpler external plants. Since many of the features in the W31 engine FIE have a field tested history, it is possible to finalise on the predicted lifecycle and cost of ownership of the new W31 injection equipment. It has been an exciting decade.

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。ABSTRACT The linking between the striving for higher efficiency and global tightening of emissions legislation is one of today’s biggest technical challenges in the field of large bore engines. In case of raw emissions, gas-fuelled engines show a lower concentration of pollutants like carbon dioxide compared to other fossil fuels. To achieve high efficiency and lowest level of emissions altogether, lean-burn gas engines are a promising approach of reciprocating engines. In terms of insignificantly changed components, the operating conditions may have modified, which can exhibit wear. Valve wear is an example that links the global tightening of emission legislations and the striving for more efficiency. Operating conditions created by lean-burn concepts, efficiency enhancing measures such as, for example, higher peak cylinder pressures, customized valve timings or the compact design of cylinder heads can lead to an aggravation of the operational boundary conditions, which impose detrimental effects on the tribological contact pair of valve spindle vs. seat ring. Consequently, valve recession increases and lifetime decreases. The contact pair valve spindle/seat ring becomes more sensitive to the load collective, leading to unexpected failures of the engine. The first part of this contribution will deal with the wear behaviour of different hardfaced valve spindles obtained from engine tests. Stellite® 12 as well as Tribaloy®T400-hardfaced valve spindles of the same type from the same engine were comparatively analyzed with regard to valve recession, oxygen penetration depth and formation of a protective anti-wear tribofilm on the valve seating faces. As response to the load collective of contact, the severely worn sealing interfaces show no protective tribofilm whereas a wear-minimizing oxide film is observed on the valve seating faces showing low wear. The results from the engine tests were compared with prelimimary results from tests with the novel test rig - a valve spindle tribometer. In order to investigate the correlation of wear behavior and load parameters, the valve spindles were tested at various temperatures, atmospheres and valve closing velocities. Whereas the focus in the first phase is on inlet valves. By the use of an environmental chamber, a reliable and controlled atmosphere was ensured. From the comparison of engine tests with the lab-scale experiments, the measured linear wear rate of 2.2 µm/h is of the same magnitude as for the excessively worn valves of about 3.6 µm/h from engine test. Hence the test rig has proven that is able to produce wear rates those found in engine tests. Consequently, it establishes a research tool for study the wear mechanisms of valve closure and peak cylinder pressure in detail in a sustainable way.