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。 Although 3D (metal) printing is not a brand new technology it is currently seeing some tailwinds. There is a strong need for building prototypes faster and almost a hype to produce parts without any limitations, rethinking traditional ways of component design and manufacturing. The target in a competition between the big players of all industrial areas is to be the frontrunner, implementing 3D metal printed parts into serial production. This technology is able to break boundaries of conventional design and manufacturing. GE is making great progress with metal additive manufacturing in multiple areas. This article will give an overview on the actual status in printing technologies, identification criteria for components targeted for serial production, with a focus on the area of reciprocating engines. GE is targeting to serialize this technology to lever all the advantages and new option at its best. There for a radical new design process needs to be implemented to use the potential of this technology and make it cost competitive compared to conventional manufacturing technics. The article will describe the new approach, from design to prototype and finally serial production, shows pro’s and con’s and what new additional selection and design criteria needs to be considered. A huge variety of different parts and assemblies for serialization have already been identified but just the tip of the ice berg is seen, the next level will go in a systematic approach across the current component fleet. Main interests are high chip volume, complex assemblies or weldings, intense machining hours, with the additional target to produce at lower cost. Near future trials with hybrid printing, a combination of different materials & properties, will potentially offer us a complete new level of design combinations and possibilities. Crucial for the success of this technology is to re-imagine the design process and close out boundaries that have been forced into the heads of the engineers.

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 cyclic combustion variation is an inherent characteristic of premixed combustion engines affecting not only the reliability of engine components but also the engine efficiency and power stability. The homogeneity of the mixture lambda and the distribution of the residual gas are generally recognized to be the main causes of combustion cycle variation. However, recent studies conducted by the authors and discussed in this paper, have revealed the effect of two additional factors contributing to the cyclic combustion variation. One factor is the autoignition of lubricating oil occurring prior to the ignition timing and resulting in combustion cycles with very high firing pressures. This phenomenon is the common issue nowadays for the majority of the premixed combustion engines with high mean effective pressure. Furthermore, the autoignition of the lubricating oil, when occurring after the start of combustion, has been found to enhance the rate of combustion causing a stochastic increase in the maximum firing pressure, hence, contributing to a worsening of the combustion cyclic variation. A second factor is the variation in the location where ignition occurs within the electrodes of a spark ignited engine. It has been observed that small variations in the location of ignition can cause different rates of flame kernel growth, resulting in large variations of the maximum firing pressure. While the development of the flame kernel is strongly influenced by the flow field at the location where the spark breakdown occurs, the parameters determining the location of the breakdown are also analyzed and discussed in this paper. The effects of lubricating oil autoignition and location of ignition on the combustion cyclic variation are described with advanced CFD technology combined to experimental data. Moreover, a demonstration of some potential countermeasures, aiming at reducing combustion cyclic variation in premixed engines, is provided with the help of CFD.

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 effect of chemical composition of residual fuels on its ignition and combustion quality was investigated. In order to control the aromatic and paraffin hydrocarbons content, 18 sample fuels with a kinematic viscosity of 380 mm2/s were produced with different proportions of a straight-run light gas oil (LGO), a vacuum gas oil (VGO), a FCC light cycle oil (LCO), a FCC clarified oil (CLO) and a Vacuum Residue (VR). Their ignition, combustion and afterburning characteristics were examined by using Fuel Combustion Analyzer (FCA), and detailed chemical analyses were also conducted by using Thermo Gravimetric Analyzer (TGA) and Gas Chromatography - Mass Spectrometry (GC/MS). Addition of LCO and CLO led a longer FCA Ignition Delay (ID), and it depends on the total amount of LCO and CLO. Though 4 sample fuels, contain none of a straight-run component, exhibited a significant longer FCA ID, their poor ignition property cannot be recognized clearly by Estimated Cetane Number (ECN) and CCAI. The straight-run components, especially LGO, can improve FCA ID. The amount of VR does not affect the combustion property. Good ignition can lead good burning of VR which contains long paraffin hydrocarbons. Based on these results, we operated a 4 stroke 257kW engine by using some fuels with different chemical composition including MGO, HFO and indirect/direct desulfurization products. The indirect/direct desulfurization products might be used for base components of fuels to comply with the Emission Control Areas (ECA) and global sulfur cap. The exhaust gas emissions were measured using by the flue gas O2, CO, CO2, NOx, and SO2 Analyzer, Particulate Matter (PM) measurement method, Thermal Optical Analysis (TOA) and a filter smoke meter. The effect of fuel type on soot concentration was obviously observed. For example, the soot concentration when operating with indirect/direct desulfurization products was very low at higher load, engine in optimum condition, it was lower than that in MGO operation. In contrast, the soot concentration increased significantly at lower load, when engine operating with direct desulfurization product was higher than with HFO. It was supposed to be resulted from fuel injection condition.

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 global warming problem caused by a large amount of discharged carbon dioxide from the use of fossil fuel required urgent measure to overcome this matter. In addition, the depletion of fossil fuel is thought as a huge problem for near future. Thus these problems have attracted many attentions of using biofuels especially that derived from vegetables oils as an alternative fuel for internal combustion engine. Due to the attractiveness of biofuel, a number of studies were conducted for examining the engine performance and emission characteristics of biodiesel used in diesel engine. The authors also conducted the systematic fundamental studies examining the spray combustion characteristics of biodiesels such as palm oil methyl ester (PME), coconut methyl ester (CME) and rapeseed methyl ester (RME) and reported in CIMAC 2010 and SETC 2013. However, as biodiesel consists of some kinds of fatty acid methyl ester (FAME) thus it is difficult to determine the major factor governing the combustion characteristics of biodiesels. Therefore, in this current research we used different types of FAME which present in biodiesel.

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。In the forged crankshafts for diesel engines, there inevitably exist non-metallic inclusions which have been generated in the steel making and casting process of large ingot. It is generally known that fatigue cracks frequently initiate from inclusions especially for high strength steel. The design fatigue strength of crankshafts, however, is defined only by the tensile strength of used steel grade in accordance with such as IACS UR M53, so that it has adequate safety margin even if crankshafts contain large size inclusions in the steel. Nowadays, the remarkable progress in steel making technology has enabled manufacture of “clean steel”, which contains a lower number of and a smaller size of inclusions. A higher design fatigue strength could conceivably be applied to such clean steel by clarifying the effect of inclusion size on the fatigue strength of crankshafts. Therefore, the following are discussed in this study. (1) To estimate the relationship between the fatigue strength and the maximum inclusion size in the crankshaft. (2) To confirm that this relationship is valid to the full scale of crankshafts. (3) To estimate the fatigue strength under multiaxial loading of axial and torsion to them in the operating condition taking inclusion size into account.

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。Top bracings are widely used to control vibration resonances of engine/hull structures and to reduce the vibration of the engine frame itself in transverse and sometimes also in longitudinal direction. Therefore and because top bracings form an additional transmission path for engine excited vibrations they also may influence positively or negatively in reducing the vibration response of other machinery and equipment as well as the ship structure. Currently two types of top bracings are used: mechanical top bracings with a friction connection and hydraulic top bracings. Main advantages of the hydraulic top bracing are their improved ability to compensate relative deflections between the engine and the ship and that their dynamic characteristic can be controlled by different settings. Compared to the conventional mechanical top bracings MAN’s hydraulic top bracings have two basic settings that can be controlled by engine speed: the standard active setting and the passive setting. While in the active setting the hydraulic top bracings acts like a spring with a certain amount of stiffness, similar in its behaviour to the mechanical type, in the passive setting it acts like a damper. To get more insight about the dynamic characteristics of hydraulic top bracings and its influence on the engine and structural vibrations, MAN conducted several measurements on board different ships. Based on the measurements, the working principle and the effectiveness of the hydraulic top bracings were proven. Furthermore their stiffness and damping properties were studied. In addition to the active and passive setting also a third condition was assessed: the top bracings were drained from oil, a condition similar to no top bracings at all. Furthermore the correlation between these different top bracing settings and the vibrations response of the superstructure was investigated. In a joint project, DNV GL and MAN aimed at correlating the measurement results by the simulation findings. Based on a validated simulation model it was then even possible to investigate several more different non standard configurations and settings by additional simulations. The additional simulations covered the influence of increasing the amount of top bracings, the top bracings stiffness, but also the effect of applying top bracings in both sides of the engine structure (double sided arrangement in port and starboard side of vessel). In the paper MAN’s measurements and DNV GL’s corresponding simulations will be presented, compared and discussed.

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 harmful exhaust gas emissions from marine diesel engines are NOx, SOx, and particulate matter. For NOx and SOx, the IMO Tier II regulation went into effect in January 2011, and the regulation is strengthened in the Tier III. On the other hand, for particulate matter, an action to reduce the sulfur content of fuel oil is adopted for the nonce. In recent years, there is a problem of global warming and rising sea levels. Marine diesel engines are strongly reduce particulate matter containing black carbon particularly in the high-latitude region. Given this situation, it is important to understand the characteristics of particulate emission from marine diesel engines and the influences of differences in measurement conditions. In this paper, particle size distribution and mass concentration of particulate matter from marine diesel engines were measured with 2 types of marine diesel engine, such as, high speed four-stroke engine (3L13AHS, 73.55 kW) and low speed two-stroke engine (3UEC33LSII-Eco, 1,275 kW). Furthermore, particle size distribution was measured by a hot-dilution method and a cooled dilution method. In the hot-dilution method, exhaust gas from the engine is diluted with high temperature air. Two types of marine diesel fuel, low sulfur fuel with a sulfur content of 0.089 %, and high sulfur fuel with a sulfur content of 0.73 % were used for the tests. Mass concentration of particulate matter was measured with the dilution tunnel system (compliant ISO8178-1), and divided into SOF (Soluble organic fraction) and ISF (Insoluble organic fraction) by Soxhlet extraction method, and PM particle size distribution was measured with the Scanning mobility particle sizer (SMPS) and Electric low pressure impactor (ELPI). The effects of the dilution ratio and the dilution air temperature in the dilution tunnel on particle size distribution and mass concentration of particulate matter were examined. The results of this experiment are as follows: (1) In the measurement by SMPS, the mode diameters of particle size of particulate matter from the marine diesel engines are below 100 nm for all experimental conditions. (2) Comparison of particulate size distributions by the hot dilution method and the cooled dilution method shows that a nucleation mode of volatility component within the particulate matter in the dilution tunnel is generated clearly. (3) For the two-stroke diesel engine, the mode diameter of particulate size become larger at high engine load condition, and this fact suggests that Brownian coagulation particulate matter has occurred. (4) In the measurement by ELPI, the particulate size distribution shows bimodal distribution under the weight concentration analysis. (5) The number concentration of particles of particulate matter from four-stroke marine diesel engine is higher than that of from marine two-stroke diesel engine for the particle of less than 100 nm diameter.

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 high speed diesel engines are typically developed as multipurpose platforms which are then used in very different application segments such as in mining, marine, power generation, etc. The operation profiles of these individual application types vary in a very wide range: from highly loaded mining machinery operating with an extreme number of load cycles, over to more constant load profiles in prime power generation, to only a few running h

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。The major research project named HERCULES-2, which started in May 2015, is the next phase of the R&D programme HERCULES on large engine technologies, which was initiated in the year 2004 as a joint vision by the two major engine manufacturer groups MAN and WARTSILA. Three consecutive projects namely HERCULES - A, -B, -C spanned the years 2004-2014 with a combined budget surpassing EUR 80Mio. These three projects produced exceptional results and received worldwide acclaim. The current project HERCULES-2 is targeting at a future fuel-flexible large marine engine, optimally adaptive to its operating environment. The targets of HERCULES-2 build upon and surpass the targets of the previous HERCULES projects, going beyond the current state-of-art. The objectives of the HERCULES-2 project are associated to 4 areas of engine integrated R&D: • Improving fuel flexibility for seamless switching between different fuel types, including non-conventional fuels. • Formulating new materials to support high temperature component applications. • Developing adaptive control methodologies to retain performance over the powerplant lifetime. • Achieving near-zero emissions, via combined integrated aftertreatment of exhaust gases. By applying advanced engineering methods and tools and furthermore by combining cutting-edge technologies, the project aims at significant fuel consumption improvement and emission reduction targets. Some of the integrated solutions, are expected to quickly mature into commercially available products.The project also aims to constructseveral full-scale prototypes and shipboard demonstrators. The project consortium comprises 32 partners of which 35% are Industrial and 65% are Universities / ResearchInstitutes. This paper gives an overview of the achievements of the past HERCULES projects, which reflect the technologicalchallenges and needs of the industry and describes the evolution towards the objectives and work-plan of the current HERCULES-2 project, presenting the initial results in all areas.

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。The improvement of power performance of large 2-stroke marine engines results in increasingly high thermal load of combustion components, which is a great challenge on the engine reliability. In order to ensure reliability, the structure optimization based on thermal load analysis is necessary. The accurate temperature field analysis on combustion chamber components is prerequisite for precise thermal load. This paper introduces the CFD-FEA coupled analysis of temperature field of cylinder head and liner. With the aid of a 3-D CFD software, AVL-FIRE, the cooling water system of the engine was simulated, and the flow velocity distribution and heat transfer coefficient distribution of cooling water were output. Meanwhile, the working process of the engine was calculated to analyze the working fluid temperature in the combustion chamber and the heat transfer coefficient distribution in the working fluid side of the combustion chamber. The CFD simulation also provided the thermal boundary conditions of main surface in the working fluid side and cooling water side. The threedimensional finite element model of the cylinder head and liner was established. Based on the CFD-FEA couplingmethod, the thermal boundary conditions of the main surface provided by the CFD simulation were mapped to the surface unit of the elements in the Finite Element Analysis (FEA) model of the components. Then the temperature field of the coupled combustion chamber components was calculated. The simulation results include the steady temperature field and heat flux distribution under the rated operating condition. The results show that the temperature field is inhomogeneous along the circumferential direction and two high-temperature zones concentrate on the wall surface of the cylinder head. The thin-walled structure or cooling boreholes will increase the local heat flux, which improves cooling performance and reduces thermal load.