论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 Computational fluid dynamics supporting the optimization of combustion systems of large Marine Diesel engines require sub-models for spray, evaporation and combustion modelling. In this paper, the further development of these sub-models and their application to engine simulations are described. The sub-models are validated against reference data from an experimental setup consisting of an optically accessible, disk-shaped constant volume chamber of 500mm diameter with peripheral injection into a swirling flow-the Spray Combustion Chamber(SCC) developed in the context of the HERCULES(High Efficiency R&D on Combustion with UItra Low Emissions for Ships) research program and presented for the first time in CIMAC 2007, Paper No.98. This unique experimental test facility for investigating the spray and combustion behaviour under conditions relevant for large marine diesel engines not only resembles the physical dimensions of large two-stroke engines but also the operational characteristics with regard to thermo-and fluid dynamic conditions at start of injection are reproduced with excellent repeatability. In particular, pressure, temperature and swirl are close to the levels experienced in those engines. Additionally, a wide range of fuel qualities can be used. The highly flexible optical accessibility enables the generation of appropriate reference data and the application of non-intrusive spray and combustion diagnostics contribute to an in-depth under-standing of the involved in-cylinder processes. Combustion is particularly sensitive to the fuel vapour distribution; therefore the accurate simulation of spray and evaporation processes is seen as a prerequisite for reliable combustion and emissions formation simulation results. The various experimental investigations that have been performed to gain knowledge about the fuel spray characteristics during injection, the evaporation behaviour and the subsequent ignition and combustion resulted in a reference data set that has been applied to the further development and validation of improved CFD sub-models. The in-nozzle flow and primary breakup of fuel nozzles was analyzed in detail and intensive investigations will be performed during the course of the research project HERCULES-C, to describe the influence of geometrical design features and flow conditions inside the nozzle. As spray and droplet formation in large two-stroke engines is highly unsymmetrical a primary breakup model was developed taking into account asymmetric boundary conditions at the orifice outlet. Finally, the improved method-ology developed is applied to investigate current is-sues of engine performance optimization like combustion with high EGR content. The actual CFD supported combustion system product development process is described and exemplified on the basis of the development of the W-X35 engine.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 Turbocharger condition is critical for the performance of turbocharged Diesel Engines and especially large scale 2-stroke ones. In this case, in addition to increasing power density, the turbocharger must also maintain a positive difference between exhaust and inlet pressure to facilitate cylinder scavenging. In large scale 2-Stroke Diesel engines the mass flow through the engine, and therefore A/F ratio, is greatly influenced by turbocharger performance. In the present paper it is presented a theoretical investigation to determine and quantify the effect of turbocharger performance degradation on the performance characteristics of a slow speed 2-stroke marine Diesel engine. The closed cycle is modelled using a multi-zone phenomenological combustion model. For the gas exchange, the filling and emptying method is applied. The model has been extensively validated for cases of Heavy Duty four stroke Diesel Engines, and has been modified to capture special characteristics of large 2-Stroke Diesel Engines operating on HFO. The T/C turbine and compressor are simulated using newly developed physically based quasi-dimensional models. Flow is solved at key stations along the T/Components, while flow losses and angles are derived from semi-empirical correlations. For the turbine a modified version of the Ainley and Mathieson axial turbine performance prediction technique is applied. The compressor is modelled using a mean line model of ra-dial compressor performance. For the turbomachinery models calibration, data from the Engine NO, Technical file are used (where air and exhaust gas flow data are provided). Thus, it is resolved the problem of limited availability of turbomachinery maps, which is very common for field applications. The complete engine model is validated through the comparison of predicted performance data against the corresponding values of the shop tests. Using the model, various scenarios of turbocharger performance degradation are investigated. The effect of turbine efficiency reduction, compressor efficiency reduction saw as their simultaneous reduction are investigated with respect to their impact on engine performance. The effect of turbine nozzle ring fouling on engine operation is also investigated since this is a common problem for two-stroke marine diesel engines. From the analysis of generated results, it is possible to develop a methodology for turbocharger condition monitoring that will allow safe detection of the actual component fault.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 The current study is motivated by the upcoming IMO-Tier 3 emission legislation demanding a drastic cut in NOx-emissions. Injectors with a cylindrical and two conical nozzle geometries were studied in order to identify features that comply with the over-all strategy of engine-internal emission reduction using exhaust gas recirculation. The work is concerned with a numerical analysis of the nozzle internal flow and the spray break-up depending on the geometric parameters of three different nozzles. For the simulation a1D-hydraulic model of the injector was coupled with a3D-CFD-calculation of the nozzle internal flow and the spray simulation. All models applied have been developed and calibrated using a reference configuration which was experimentally investigated at an injection rate analyzer and a high-pressure, high-temperature injection chamber. The simulated results of the reference set-up are in good agreement with the experiments proving the suitability of the models and calibration. Comparing the calculations, distinct differences in the nozzle internal flow field and spray penetration were found especially between the cylindrical and conical geometries. While increasing the conicity from k=0 to k=3 reveals apparent changes of the nozzle internal flow and spray characteristics, a further rise of conicity from k=3 to k=6 did not show any significant changes. Based on the obtained results it can be assumed, that alternative nozzle geometries may induce a positive impact on emissions of medium speed diesel engines. In the framework of the ongoing research project FAME an experimental study of the investigated nozzles will be performed at a high-pressure, high-temperature injection chamber and a single cylinder research engine giving the opportunity to validate the results and conclusions presented in this paper.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 The ammonia SCR technology is an efficient instrument for denitrification of exhaust gases and therefore an approved technology to comply with the IMO Tier ll limits (within Emission Control Areas). It is successfully used in the on-road sector as well as in several maritime and stationary large diesel engine applications. The operation of large diesel engines with highly efficient TC systems (e.g. two-stroke engine with single-stage TC or four-stroke engines with two-stage TC) however shows very low exhaust gas temperatures downstream the TC turbines. At the SCR system, these boundary conditions not only lead to low reaction rates of the nitrous oxides with the reducing agent ammonia but also cause unwanted side reactions of sulfur oxides contained in the exhaust gas with the ammonia. The formation of ammonium sulfate can lead to a blocking of the SCR monolith and therefore to a decrease of reactivity up to a complete deactivation of the system. Those effects not only occur when running on residual oils with increased sulfur contents but already by operation on distillate fuels of higher quality with a sulfur content of 0.1%. SOx scrubbing upstream the SCR-system would result in further decreased temperatures which will further intensify the loss of reactivity. Approaches to solving this problem have to provide higher temperature levels of the exhaust gases at the inlet of the SCR-system. An efficient solution is presented by placing the SCR upstream the turbine of the TC system or between the turbines (in case of two-stage TC). The SCR operation would benefit from the higher exhaust gas temperature levels and an energy consuming reheating of the exhaust gases can be avoided. This would require are arrangement of the exhaust gas system to accommodate the SCR-catalyst and the dosing unit for the reducing agent upstream of the last turbine stage. In opposition to known and already in-use SCR-systems, which are placed behind the TC turbine, the effects of the increased pressure levels at the pre-turbine position on the SCR system and on the reaction kinetics are still widely unknown. Therefore, the effects on the ammonia storage capacity, the chemical conversion rates as well as on the SCR system itself are investigated experimentally. A synthesis gas test bench and a single cylinder research engine with a CR injection system are used for the analyses. Both test benches offer the opportunity to adjust the operation conditions equal to those upstream the TC turbines of large diesel engines. Here, the exhaust gas temperatures, the composition and especially the pressure level are of main interest. At the synthesis gas test bench the parameters temperature, pressure and space velocity are varied and the effect of those boundary conditions on the SCR system are studied systematically. The results from the synthesis gas test bench are compared with measurements using real exhaust gas at the externally turbocharged single cylinder research engine. Here, the exhaust gas back pressures are also adjusted similar to a pre-turbine application of the SCR. Additionally, the influence of particle loaded exhaust gas is taken into account. The chosen catalyst samples are honeycomb structures with oxides of vanadium, wolfram and titanium which is typically used in maritime applications and conventional arrangements of the SCR system downstream the TC.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 Component design procedures have developed significantly during the last decades. As a part of the process, the prediction of accurate stresses using the Finite Element Method (FEM) as well as the calculation of fatigue strength with specific codes, have become common practice. Due to ever-increasing computational power, different surface treatments, which contribute to the formation of the local microstructure and stress situation, such as heat treatment or shot peening, can also be integrated in the FE-model. The determination of the fatigue life of a component can be automated to some extent for the sake of decreased design time by using numerical methods. When the outcome of a surface treatment is taken into account in such an analysis, it naturally gives the analyst an opportunity to optimise not only the geometry, but also the desired surface treatment influence on the component. This in turn leads to the fact that the parameters of the surface treatment procedure in manufacturing can be defined more precisely already in the designing phase leading to obvious cost savings. Case hardening is a surface treatment process in which the surface of a metal is hardened by infusing elements into the material. More specifically carburization, where the component is introduced to a carbon-rich environment at an elevated temperature and afterwards quenched so that the car-bon stays in the structure, is a commonly used method for improving the wear and fatigue resistance of several engineering components. The advantage from the fatigue point of view of this procedure is naturally the increase in hardness as well as the compressive residual stresses in the surface of the component. The disadvantage, on the other hand, can be found underneath the surface in a form of balancing tensile residual stresses, which in turn may be a source location for a possible failure initiation. This paper introduces an approach for dimensioning a component, which has been hardened by carburization. The focus of the exercise is on defining the correct case hardening profile in order to meet the required probability of survival. As an example, a gear from a thruster manufactured by Wartsila Netherlands B.V. is investigated, where the teeth of the gear wheels are treated. The examination is conducted through the component surface until a certain depth in order to also take into account the influence of the tensile part of the residual stresses. Those are then combined with the working stresses during operation and based on the result, the fatigue analysis is performed. That is done by adapting existing Wartsila tools including the multiaxial damage models of Findley and Dang Van together with the concept of local fatigue strength, which defines local fatigue limits through depth based on the hardness variation. The material parameters used are obtained by testing and finally the calculated results are compared to available real world data.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 The details of the SCR development at MAN Diesel and Turbo are presented. This is both concerning the catalyst application, the requirements to the engine control system and identified challenges in connection with the SCR application. Furthermore, the fist costs and operating cost are considered and the influence of reducing agent is discussed from both a technical and an economic point of view. An alternative mixer application for the next generations of SCR systems is also described, and finally suggestions for different NOx sensor strategies are summarised.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 More stringent legislations regarding the emission of pollutants are a big challenge for engine manufacturers, suppliers and operators. As a result of those strict targets for CO2 reduction, the use of alternative fuels is moving forward. An interesting alter-native to diesel engines is presented by gas-powered engines, where it is possible to reduce emission of pollutants significantly. Typical gaseous fuels for gas engines include natural gas, biogas, propane and butane, differing mainly in the calorific value, density and stoichiometric ratio. As a consequence of the different gas properties, depending upon which gas is used in a particular engine type, the gas flow rates can differ immensely for the same engine power output and, conversely, different dimensions of the gas train have to be designed and installed for the same engine type. In the power range of 0.5 MW up to 4MW, for high-speed engines (1500 rpm) typically a gas dosing unit is applied, which actuates a throttle valve to control the gas flow. The limited control of small gas flow-rate due to the nonlinear behavior of the throttle valve leads to different valve sizes for the different gas types on one engine type and to increasing costs of stock holding and production. Due to these facts, Heinzmann decided to begin the development of a new generation of gas flow control valves. An essential target of this development was a wider variety of the turn-down ratios compared to the existing systems in the market. Furthermore, special attention was paid to the production costs. Both requirements could have been met with the use of special geometries and the implementation of existing control devices. In this presentation the stages of development, design and bench testing are presented.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 PM emitted from diesel engines has harmful effects on human respiratory organs. Consequently, a severe restriction on its emission amount has been implemented and various PM reduction de-vices have been developed for cars. However, these PM reduction devices which utilize a catalyst are not applicable to ships. This is because heavy fuel oil (HFO) used for ships contains a large amount of sulfur. PM from marine diesel engines is composed of dry soot, soluble organic fraction (SOF), and sulfate. Regulations for decreasing the sulfur content in the fuel have been proposed by IMO. Implementation of these regulations will reduce the amount of sulfur in fuelfrom3.5% to 0.5% globally by 2020 or 2025, and from 1.0%to 0.1% in the Emission Control Area(ECA) by 2015.Reducing the sulfate content will decrease the total amount of PM emission from ships significantly, but the amount of dry soot and SOF emissions will remain the same. In this study, a basic experiment to investigate the effects and reproductions of a PM reduction filter for marine diesel engines was conducted. And then, a newly developed diesel particulate filter (DPF)with a regenerator was connected to the exhaust line of a high-speed marine diesel engine, and the effects of PM reduction and engine performances were investigated. The outlines of the experiments are as follows. (1) Effect of DPF on PM reduction: To clarify the effect of PM reduction by DPF, the filter material used for DPF was installed between the PM sampling probe set in the exhaust line of the test engine and the dilution tunnel. The components of PM were compared for the cases with and without the filter material. The engines used for the experiments are the low-speed marine diesel engine (7,722 kW) of the training ship Seiun Maru' which uses HFO and the high-speed marine diesel engine (103 kW) of the laboratory of National Fisheries University which uses gas oil and Marine Diesel Oil (MDO). (2) Effective temperature and time for filter regeneration: Various temperatures were investigated for a given time in order to determine the appropriate temperature for filter regeneration in DPF.The collected elements on the filter were place into a furnace at a given temperature and the time required for regeneration was recorded.(3) Effect of the newly developed DPF on PM reduction: DPF with a regenerator was connected to the exhaust line of a high-speed marine diesel engine, and the effect of the device on PM emission and engine performance was investigated.(4) Regeneration of DPF: To remove PM on the filter, DPF equipped with a heating apparatus and the filter was developed. DPF was installed in the exhaust line of the engine, and an experiment on the regeneration of DPF was conducted. As a result, for practical applications of DPF for marine diesel engines, the following must be satisfied. (1)A comparison of the experimental data demonstrates that most of the dry soot can be removed by DPF, but SOF and sulfate remain. This is because the required high temperature for passage of the exhaust gas through DPF causes SOF and sulfate to become like gases. (2) The optimum temperature for assuring complete regeneration within the first few minutes at a minimum electric power is determined to be 650℃. Temperatures lower than 650℃ result in longer regeneration times, which is insufficient. Temperatures higher than 650℃ may lead to shorter regeneration times, but the cost for the required electric power increases.(3) Though most of the dry soot and some of the SOF and sulfate in PM can be removed by DPF, it has been known that specific fuel consumption(SFC) deteriorates by 3% when the exhaust gas pressure increases by a1 0-kPa inter-val.(4) PM can be removed by heating the filter to650℃ or more. As a result, a continuous regeneration of DPF becomes possible without the need to change the filter.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 Although international shipping is the most carbon efficient mode of commercial transport, it was still estimated to have emitted 870 million tones CO2 in 2009. Part of the emission is generated by ship auxiliary engine that produces electricity for refrigeration and other electric devices on-board, while large amount of exhaust heat from ship propeller engine is wasted without further utilisation. Through ap-plying new technologies, thermal energy management work can be done on waste heat recovery and utilisation on-board, in turn, achieve carbon abatement of shipping. Based on a Ro-Ro ship travelling regularly at northern Atlantic Ocean, a ship propeller engine heat driven refrigeration and cooling storage system is developed in terms of the transport schedule of the case ship. The thermally-activated absorption refrigeration saves about 40 kWe from auxiliary engine. The ice-slurry cooling storage system releases cooling at ports while the propeller engine heat is unavailable, therefore the overall refrigeration system generates zero carbon emission at ports, which could meet the most stringent policy in some emission-controlled areas. The estimated annual emission reduction on this Ro-Ro ship is about 1176.85 tCO2 if the new system is applied.

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 The objective of the paper is to present experimental results gained from a long-stroke medium speed diesel engine. The study is carried out on the 3-cylinder long-stroke FMC 4524 research engine located at Flensburg University of Applied Sciences in cooperation with ABB Turbo Systems, Baden. Based on a IMO ll Layout of the engine featuring • High stroke/bore ratio of s/d=450mm/240mm=1,875, • optimized mechanical efficiency based on crankshaft design acc. to classification rules, • combustion chamber design optimized for high compression ratio(=17.8), • 2 stage High Pressure Injection System with variable injection pressure, • Single Stage Turbo Charging,· and standard Inlet Valve Timing, Two Stage Turbo Charging and Miller Cycle Inlet Valve Timing were applied in several steps. In parallel modifications to the exhaust gas system were applied to improve part load and startup performance. Also variations of exhaust gas valve timing and injection characteristics were executed. The project is primarily aimed at reduction of CO2-and PM-Emissions in the envelope of IMO lll exhaust gas regulations for non ECAs. In an intermediate development step Inlet Valve Timing was moved to 42℃A before BDC(Miller42) and 50℃A before BDC (Miller 50). The first results of Miller 42 showed a reduction of fuel consumption to 168 g/kWh, meaning a CO2-Emission reduction of app.6% based on the values of the base engine. PM-Emissions stayed constant on the low level of the base engine. In opposition to the expected trend Nitric Oxide Emissions could be reduced by 20% down to about8g/kWh. Further development steps will include tests with more extreme Miller-Configurations up 60℃A before BDC. Additionally, pilot-application of other means for emission control like EGR and Fuel-Water emulsion are planned to evaluate further emission reduction potential aiming at emission regulations for ECAs.