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。One of the best methods to reduce greenhouse gas emissions of thermal energy generation systems is to use wastederived fuels. In Finland, high-quality liquid engine fuels are produced from various wastes, e.g., animal fats, biproducts of forest industry, and wastes of food industry. In this study, three different liquid renewable fuels were investigated in a turbo-charged, intercooled common-rail nonroad diesel engine. The fuels were animal fat based methyl ester (AFME), hydrotreated vegetable oil (HVO), and biodiesel from fish wastes (FISH). As the baseline fuel, commercial low-sulfur diesel fuel oil (DFO) was used. The engine was designed to fulfill the US Tier 3 emissions legislation. The engine was driven according to the 8-mode cycle C1 of the ISO8178 standard. In addition to the basic engine performance and regulated gaseous emissions, the exhaust smoke and particulate number emissions were determined. For all studied fuels, similar rated engine output and maximum torque were used. Due to the lower volumetric heating values, the injection periods were at some loads slightly longer for AFME, FISH and HVO relative to DFO. No deliberate modifications were, however, made for the injection strategy. The smoke emissions were the lowest with AFME and FISH, both of which showing very similar results. DFO emitted the highest smoke and the results of HVO were between those of DFO and esters. At low load at rated speed, HVO showed, however, almost as low smoke readings as AFME and FISH. At high loads, FISH produced the highest NOx emissions, HVO usually showing the lowest NOx. At maximum torque, the NOx with HVO was more than 20% lower compared with FISH. At rated speed, DFO was almost as favorable as HVO but at very low load the NOx was slightly the highest with HVO. Regarding CO emissions within the upper half load range, there were no big differences between the fuels, the esters having slightly the lowest recordings at 75% and full loads at intermediate speed. At low loads, HVO was the most beneficial concerning CO emissions. At rated speed, DFO produced the highest HC emissions, HVO, AFME and FISH showing lower but almost equal results each. At intermediate speed, HVO and FISH emitted the lowest HC, AFME being slightly less favorable and DFO again showing the highest HC. The highest particulate number (PN) emissions were measured with DFO, the peak value usually detected within a particle size range of 50 to 70 nm. The lowest PN was generally recorded with FISH, but AFME showed almost similar results. With the esters, the highest PN was often approximately 50% of that with DFO. Commonly, the highest PN with HVO was halfway between DFO and esters. At idle, the particle size distributions were, however, completely different. FISH produced clearly the highest emissions and HVO the lowest. As a whole, the benefit of HVO was very clearly seen just at idle. The brake thermal efficiencies were almost equal throughout the test cycle. At high loads at intermediate speed, AFME and FISH showed slightly higher efficiencies than HVO and particularly DFO, but the differences were almost within the range of the measurement accuracy. The study showed that oxygen containing waste-derived esters may form a feasible option for local energy production and off-road use, particularly when used as blends with fossil DFO. Moreover, the advantages of the high-quality renewable HVO fuel were especially clearly seen in low-load engine operation conditions.

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。Much of the heavy fuel oil, burnt in the cylinders of large 2-stroke marine diesel engines, is contaminated with hard particles known as catalytic (cat) fines. These particles, which find their way into the fuel at the oil refinery, can cause catastrophic abrasive damage to engine cylinder liners during the combustion process. This problem has been inadvertently exacerbated by recent changes to the regulation of marine air pollution because it has driven the use of cat-fine prone, low-sulphur fuel oils. As a means of self-preservation, vessels collect representative fuel samples during bunkering and then send them off for laboratory analysis. However, the test results often only become available once a ship has set sail and is far out to sea, by which time significant engine damage may already be in progress. This problem is tackled by a number of proprietary onboard products that can provide direct or indirect indications of cat fines in fuel as soon as the main engine(s) begin(s) to run. Onboard measurements also enable the continuous monitoring of the concentration of cat fines reaching the injectors after the bunkered fuel has been cleaned by the onboard purifying system. This paper begins by reviewing the various laboratory and onboard techniques that are currently used for cat fine determination; these techniques include inductively-coupled plasma atomic emission spectroscopy (ICP-AES), magnetometry, nuclear magnetic resonance spectroscopy (NMR), and x-ray fluorescence spectroscopy (XRF). A new, cost-effective method, which has the potential to yield results on board a ship within a few minutes, will also be introduced in this paper. Experimental results demonstrate that the new test is capable of identifying fuel samples that have a cat fine concentration of > 60 ppm (Al + Si), and which therefore exceed the limit recommended by ISO 8217:2012. In fact the test has been specifically designed to provide the crew with a clear sail or don’t sail indication with regards to fuel quality.

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。In this experimental engine study, the effects of renewable paraffinic NEXBTL diesel on engine performance were researched by Turku University of Applied Sciences Engine laboratory in co-operation with Neste Corporation. The target was to determine if it would be possible to reduce the fuel consumption of the engine with two research fuels by optimizing fuel injection parameters and the use of exhaust gas recirculation, while maintaining nitrous oxide emission levels achieved with diesel. In the first part of the study fuel injection parameters were optimized separately to determine the effects of each change with research fuels. The two used research fuels were neat NEXBTL and a 50-50 blend of fossil summer grade diesel and NEXBTL. A fossil summer grade diesel was used as a reference fuel. The greatest advantages for the two research fuels in comparison to diesel were seen in significantly lower smoke numbers. Fuel injection parameter optimization did not produce significant reduction in fuel consumption, as the base results of NOX were quite similar with all fuels, which made optimization possibilities quite narrow. The use of EGR reduced the NOX significantly but simultaneously the amount of smoke rose. When NOX was brought back to the reference levels by optimizing the fuel injection parameters, notable gains in fuel consumption were noticed. At the same time the smoke numbers were clearly higher than the reference level. No significant constant differences between the three fuels were seen in in-cylinder results. At some lower load points shorter ignition delay of NEXBTL was measured. The NOX-results of transient cycle were quite close to each other when using different fuels. Only slight changes in fuel consumption were noticed in these runs. Two different rates of EGR-settings were used, and in addition fuel injection parameters were optimized with lower EGR-valve settings to bring NOX to the reference level. In the last part of the study a transient cycle was used to compare the fuels. Gaseous emissions, temperatures and pressures were collected with an engine controlling program. The engine used in this study was a 4-cylinder AGCO Power off-road diesel engine. Also, an in-cylinderdata was collected and analyzed via a cylinder pressure sensor and engine indicating system. The main target was to compare the results of cylinder pressures, heat release rates and ignition delays between different fuels

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 use of lubrication oil as a hydraulic medium to actuate the injection systems of 2-stroke engines is well experienced since more than 15 years now. The hydraulic oil system works like a kidney loop safe-guarding the quality of the overall oil volume. It receives additional filtration downstream the main lube oil automatic filter. A new filtration concept is introduced to enhance the cleaning of the oil during engine flushing procedures and over the entire engine lifetime. At the same time this concept is space saving and performing better in the vibrating environment on-built the engine.

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。New types of fuels enter the marine market and novel combustion principles are introduced in MAN B&W engines. This imposes challenges to the traditional cylinder lube oils, cylinder lube oil supply systems and engine components. Here, MAN Diesel & Turbo Two-Stroke presents the lubrication challenges and latest experiences for operation on fuels with less than 0.1% sulphur (S). Our future cylinder lube oil supply systems, which cover the entire fuel S range from 0-3.5%, and new components, to overcome the risk of obstructions in oil-film formation, are also discussed. Until recently, marine low speed engines and cylinder lube oils have been optimised for operation on heavy fuel oil (HFO) with a high S content. The purpose of the alkaline additives in the lube oil is to neutralise the sulphuric acid condensed on the liner wall and thereby protect the components against corrosion. When operating on fuels with less than 0.1 %S, i.e. distillates, ultra-low sulphur fuel oil (ULSFO), liquefied natural gas (LNG), methanol, ethane and LPG, only small amounts of sulphuric acid is formed and the alkaline additives in the lube oil are not needed. The unused alkaline additives tend to form deposits in the combustion chamber and these can disturb the lube oil film, obstruct the piston ring movement, polish the liner surface and thereby increase the risk of scuffing. Newly developed cylinder lube oils are available to decrease these risks. For engines operating continuously on fuels with less than 0.1%S, two components which aim to reduce the risk of seizures, polished liner surfaces and scuffing are presented. Cermet coated rings show successful results and installing a full set of piston rings with cermet coating is recommended. Cylinder oils are usually optimized for a specific S range. Ships operating in the full S range from 0 to 1.0 to 2.0 to 3.5% require several lube oil types in order to have an efficient lubrication. The Automated Cylinder Oil Mixing (ACOM) system is the solution and requires only two oils and will be available for all engines types. The ACOM mixes low-BN oil and high-BN oil to the required BN to match the fuel S content. It mixes and delivers the lube oil mixture just-in-time which facilitates the process of optimizing the lubrication and cylinder condition. Using suitable lubricants, ACOM operation can cover the complete S range from 0-3.5% and facilitate optimised lubrication. The ACOM is presently out for service testing. The Automated Cylinder Oil Switching (ACOS) system is specially developed for ME-GI engines, and facilitates the lubrication during operation on LNG and high S HFO. It is controlled by the engine operating system and switches automatically between low-BN and high-BN cylinder lube oil based on S content in the actual fuel and load applied. The ACOS system is now standard for the ME-GI engines. Successful optimization of the lubrication and improvement of the cylinder condition are dependent on that the condition is followed closely and the operators act on the information obtained. The importance of on board analysis tools, i.e. drain oil analysis, port inspections and liner surface examinations, are described and discussed.

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。 Precombustion chamber (PCC) ignition is a common method for extending the lean limit and reducing combustion variability in large bore natural gas engines. However, most of the existing PCC designs operate under “rich” burn conditions, resulting in less than optimum combustion performance in terms of BTE/NOx trade-off. This paper will show how the use of advanced computational flow dynamic (CFD) is instrumental in controlling the local magnitude of the flow velocity and the air-fuel mixture distribution and in achieving a unique design of the PCC. This creates the capability to sustain efficient and stable combustion of lean mixtures within the PCC, hence, offering the potential for significantly improving the engine BTE, while maintaining NOx levels in the range required for meeting current and future mandates. Additionally, specific regions of the PCC, with repeatable and uniform flow velocity and lambda distributions, are identified as ideal locations for a combustion ionization probe. This presents an opportunity for a reliable and cost effective way to achieve dependable combustion feedback control and extend the range of optimum operations. A review of this Novel PCC technology is provided along with experimental data obtained from a fully instrumented Cooper-Bessemer GMV engine. Also, discussed are the potential benefits of this Novel PCC technology with respect to enabling major enhancements in combustion stability, ignitability, spark plug life, and engine efficiency necessary for achieving highly optimized solutions.

The 1 MW class gas cogeneration system is expected to be spread rapidly in the near future. The objective of this study is to propose and prove a gas engine cogeneration system with high thermal efficiency and reduction in CO2 emission, which can provide a stable power supply as the supplement of unstable renewable green energy power systems like wind power. To realize the improvement in thermal efficiency, research and development of the following four element technologies were carried out by numerical simulations. Based on the results, the evaluation of the element technologies by using a single-cylinder engine has been made. 1. CO2 reduction and the maximum power increase by improving the thermal efficiency. 2. Enhancement of heat supply by increasing the amount of exhaust gas energy. 3. Improvement of the spark plug’s life and reduction of unburned methane emissions by using the low-temperature plasma technology. 4. A flexible operation achieved by stable combustion and the control of thermoelectric ratio.

Marine diesel engine is composed of many interacting components. In this study, technologies to improve tribological performance of components for HiMSEN engine are explained. Cam-roller system is used as a device for driving the valve train in HiMSEN engine. Real contact stress as well as Hertz stress is very important design parameter of cam and roller. Local contact stress concentration often cause scratches or contact fatigue damage such as fitting on surface of roller and cam. In order to obtain even contact stress distribution, logarithmic roller profile was applied. Three factors which determine the profile were optimized using micro contact analysis and RSM(Response Surface Method). Optimized profile induced 10% lower contact pressure than the previous profile. Hydrodynamic journal bearings are widely used in machinery to support a rotating shaft. In case of connecting rod bearing, lubricating oil is supplied through the rotating crank pin and high load by firing pressure acts on connecting rod body. So fluctuating oil pressure and elastic deformation of connected components should be considered to evaluate the lubrication performance of journal bearing. Elasto-hydrodynamic(EHD) lubrication analysis considering oil supply pressure variation in a cycle was carried out. Based on the analysis results, the optimum oil supply hole size and clearance of bearing were determined. Idle gear serves to transmit torque for the driving valvetrain form crankshaft to camshaft and consists of gear, shaft and shrink-fitted journal bearing. Idle gear shaft is assembled on front end block by bolts in the latest HiMSEN engine. To make sure of robust idle gear system, convergence technology that is a coming together of vibration analysis, structural analysis and lubrication analysis is applied. Through the natural frequency analysis design for idle gear shaft and supporting part of the engine block were determined. Stress analysis and fatigue analysis were carried out to design the shape of idle gear shaft having enough fatigue safety factor. Based on the EHD lubrication analysis results, idle gear bush design was optimized.

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 incidents of the political destabilization will increase in all probability our efforts to get more independent of oil-base energy sources. In addition also the tightening of the worldwide exhaust gas regulations will act as a driving force towards gas and Dual fuel engine development. When the energy demand is increasing constantly worldwide the developing countries are decentralizing their electrical power supply by using in the large stationary power plants the gas engines. Due to geo-political or environmental reasons the use of alternative fuel is also necessity, sometimes for unlimited time. Therefore the optimum thermal efficiency of the engine has to be provided both with gaseous and liquefied fuels. When considering the marine propulsion system the alternative of LNG to HFO is under an extensive discussion right now. In the LNG vessels the 4-Stroke dual fuel engine has been successfully operating for multiple years and now the customers operating with other type of vessels – like for example cruise vessels have appointed their strong interest towards the use of dual fuel engines. Also with marine application the interim operation with LFO or HFO with unlimited time is often a strong demand and therefore considered as development area what comes to combustion control and engine convertibility. This article focuses on new 4-stroke large and medium bore dual fuel engine portfolio development for marine and stationary power plant solutions concentrating on the following topics: Engine reliability, transient operation capability, operational flexibility and the increase of thermal efficiency with liquefied and gaseous fuels.

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 further development and optimization of the combustion systems of large marine diesel engines is a key element to meet the up-coming emission targets imposed by legislation as well as the increase in efficiency to attend the demands of the seaborne freight transportation market. In this context, the in-depth knowledge of the in-cylinder processes has to be seen as a prerequisite to the technology development work. Therefore, a unique optical accessible experimental test setup – the so-called Spray Combustion Chamber (SCC) – for investigating the spray and combustion behaviour under conditions relevant for large marine diesel en-gines has been developed. This facility re-sembles the sheer physical dimensions of large two-stroke engines, the operational characteristics with respect to thermo- and fluid dynamic conditions (including swirl) at start of injection. Moreover, a wide range of fuel quali-ties can be applied via an engine like injection systems. To gain information about the influence of the fuel on the spray characteristics during injection, the evaporation behaviour and the subsequent ignition/combustion, investigations under engine-like conditions have been performed, using adequate and specific measurement techniques. The macroscopic observations of the spray evolution are conducted by means of an advanced “shadow-imaging” (diffused back-illumination technique) for varying fuel qualities, i.e. light fuel oil (LFO) vs. heavy fuel oil (HFO). In particular, the difference in the evaporation behaviour as well as the propaga-tion/interaction of the spray with the swirl flow observed with experiments at inert conditions will be presented and discussed. Next, the ignition (and combustion) char-acteristics are analysed by measuring the flame illumination and OH* - chemiluminescene signals including a simultaneous capturing of shadow-imaging recordings. Hence, yielding to information about ignition delay as well as ignition (and lift-off) location at a chamber condition (pressure, temperature) representative for large 2-stroke marine diesel engines. For comparison reasons, these data are put into relation with the conditions found in the fuel ignition analyser (FIA). For an in-depth investigation of the subsequent combustion, the heat release rate has been assessed by using an appropriate calculation based on the in-cylinder pressure trace analysis. Here, a variation of three different fuel qualities (on LFO and two qualities of HFO) at different temperature and pressure conditions were studied. These investigations will provide a better in-sight into the special characteristics of the spray formation and combustion behaviour imposed by the peripheral injection into a swirling flow inside the combustion chamber. Moreover, due to the fuel flexible operation of such engines, an emphasis on the fuel quality (varying thermophysical properties) influences with regard to the injection/fuel spray evolution as well as the ignition/combustion behaviour shall extend knowledge on the involved injection and combustion processes. Finally, allowing the optimization of en-gine performance related needs and technologies as well as the development and validation of suitable calculation and simulation methodologies.