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。Due to the well-known reasons, such as the reduction of operating costs and emissions, the number of gas engines has increased a lot over the last years. Thereby Dual Fuel engines enable high flexibility and operating reliability. So unlimited engine operation is guaranteed, even if gas supply was interrupted. Furthermore gas operation with pilot injection also shows advantages in comparison to operation with spark plug, for example an increased ignition and lifetime. As global market leader for Dual Fuel injections systems L’Orange possesses more than 20 years of experience in research and development; both for engines with homogeneous combustion (low pressure gas) and also with heterogeneous combustion (high pressure gas). The appropriate engines from Wärtsilä convice on the market for many years. Despite many advantages the actual Dual Fuel injection systems show one disadvantage: they are complex and extensive and therefore need equivalent constructed size. Usually DF injection systems have two separated fuel circuits, one for pilot injection with gas operation and one for liquid fuel operation. This requires several pumps for pressurization, a double needle injector with a common rail and a pump line nozzle site respectively two separate injectors per cylinder. Currently L’Orange develops a new, obviously simplified injection system. The injection system consists only of one fuel circle with one high pressure pump plus one injector per engine cylinder. The injector possesses a one-needlenozzle, with which the pilot quantity and the full load in the fluid fuel operation are injected. Thereby challenges for the development are the realization of a stable injection quantity for the pilot injection at a sufficient fuel atomization - with the same nozzle respectively the same blowholes for the pilot- and main injection. To guarantee the required engine performance and emissions, the injection quantity has to remain stable for the whole lifetime which demands a closed control loop for drift compensation. Furthermore design-measurements are required to ensure the thermal balance of the high pressure pump and the nozzle in gas operation. Besides the design and simulation activities extensive tests on component test rigs and on the spray diagnostic rig at L’Orange plus on the engine were realized. These tests have provide good results, so first series operations are expected soon.

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。This paper provides in-depth research, analysis and testing results of the impact of significant volumes of water contamination in diesel fuel oil on the ability of large, medium-speed diesel engines to successfully start and operate under emergency conditions. This investigation came about from the discovery of degraded vent pipes on diesel fuel oil day tanks that could have allowed rain water to collect at the bottom of the diesel fuel oil system and potentially prevent satisfactory engine start-up and operation. Analytical and empirical results for those conditions, where there is no known analysis or operating experience, are described in detail. For the past several decades, a number of diesel engine manufacturers investigated the effect of introducing water into the combustion process by different methods such as water emulsion, direct water injection or inlet air fumigation. The goal of these tests was to demonstrate the positive effect of water in reducing diesel engine exhaust emissions. These efforts proved successful in achieving that goal, but the results have not seen wide-spread application by today’s engine suppliers and there remained the concern about the potential disadvantages of water and diesel fuel oil systems. In contrast to past investigations, this effort focused on completing a series of diesel engine combustion analyses using Ricardo’s WAVE©, 1D engine performance simulation software. The WAVE Diesel-Jet predictive combustion model was enhanced by combining the ignition delay predictions with external combustion efficiency calculations in order to predict the power loss and water concentration where the engine would still operate and sustain efficient combustion. Two different medium-speed diesel engine models were analyzed with added water content ranging from 10% to 40% water in the diesel fuel oil. The analyses demonstrated that the engines could start and operate with those percentages of water in the fuel, but that the engine output would experience a power loss or derate proportional to the water content. The validity of the analytical findings above was demonstrated by full-scale tests conducted by MPR Associates on a large diesel engine. To accomplish this, Entergy, the nuclear power plant owner constructed a simulation of the diesel fuel oil supply system at a facility having the same make and model emergency diesel generator (EDG) set. Water was introduced into the diesel fuel oil day tank by two different approaches; slow trickle flow and large slugs of water. These conditions simulated either a steady rainfall while the EDG was operating or a large volume of water collected in the system while the EDG was in standby. Under both conditions, which consisted of more than 50 hours of testing, the diesel engine and generator set responded with negligible loss of frequency or voltage. Further, the engine was confirmed to have undergone no increased wear or degradation as a result of the high levels of water in the combustion chambers.

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。This paper presents the design of the Ganser CRS common rail injectors with the proprietary poppet valve, the state of the art hydraulic switching component for common rail injectors. Thanks to its unique design, the combustion process is optimized by stable and rapid injection profiles, which are allowing for reliable multiple injection driving strategies to further reduce the in-cylinder emissions. Due to its universal characteristics, the poppet valve is applicable in numerous fields, of which two of them are specifically presented in this paper. The first exemplary application of the poppet valve is the common rail retrofit of a 16V ALCO locomotive engine with a power output of 3MW. In this retrofit project, the existing mechanical fuel injection system is replaced by a tailor-made common rail system. Thanks to the unique injector design, no changes to the cylinder head are necessary. The injector includes an integrated accumulator for maximized and constant injection pressures during the whole injection process. Each cylinder bank is equipped with a separate slim rail and a dedicated high pressure pump, allowing for a freely configurable injection up to 1600bar. The poppet valve is also successfully applied in the field of micro pilot injection for new dual fuel engines. On these marine engines, the micro pilot injection quantity to ignite the gas is typically 0.5-2% of the total power output. This maximized substitution is possible thanks to the accurate switching characteristics of the poppet valve at these small injection quantities. With the application of the proprietary Wave Dynamics and Dampening System (WDD) and injector-integrated accumulators, the rail can be replaced completely by so-called jumper lines.

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。Natural gas constantly expands its percentage share of the worldwide total energy consumption. This trend is expected to continue during upcoming decades. Facing varying emissions legislation and individual customer requirements, flexibility of modern gas engines for electric power generation gains in importance. In order to meet these requirements, different applications of the G20CM34 lean burn otto-gas engine were developed. The goal was to provide the nominal engine power output of 10 MW at high engine efficiency and low NOx emissions within a wide range of changing boundary conditions (altitude, ambient temperature, fuel composition, plant operation mode). The applications were placed in diverging spots regarding the tradeoff between applied Miller cycle, required intake manifold air pressure and maximum compression ratio below the knock limit. As a result customized engine setups can be provided, serving customer individual needs at specific sites. The capability of simulation tools is permanently enhanced, but some impacts of design changes on engine performance can still not be reproduced or predicted. That is why a validation of an entire development concept at the first prototype engine involves a high risk not to achieve the stated development target. This was the main driver to implement a 3-cylinder test engine in an iterative gas engine development process. The highly flexible test setup provides the possibility to assess gas engine operation within a wide range of adjustable boundary conditions at the required high turbocharging efficiency. Optimizations like crevice volume reduction and improved pre chamber designs were realized by the use of various simulation tools. The resulting impact on combustion performance could separately be assessed by the analysis of the obtained test engine data. Adjoining, the durability of selected components could be proved during according endurance runs. So a substantial portion of the development effort could be shifted to the test engine, where the thermodynamic concept could be validated in an early stage of the project. As a consequence, engine settings could be determined in advance and the required test time for prototype engines significantly reduced. The lean burn concept with pre chamber enables high engine efficiency at relatively low NOx emissions. Whereas power density of modern gas engines is still restricted by events like knock, misfire, abnormal combustion and pre ignition. Cylinder balancing in combination with advanced engine controls represents a reasonable approach to generate several benefits to mitigate these limitations. Potentially engine efficiency or power density can be increased. Furthermore, the operating range under challenging boundary conditions can be extended. Parameters to characterize the combustion process are required as input for cylinder balancing and advanced control efforts. A cylinder pressure based control system was chosen to provide this input. Being applied at the 3-cylinder test engine, its global functionality could be validated and different control strategies evolved. Enabled by the described gas engine development process, costs were reduced and the development cycle of the project significantly shortened. Outcome of the G20CM34 gas engine concept are different applications to satisfy customer individual requirements all around the world.

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。Caterpillar develops medium speed Dual fuel engines for marine applications in the power range from 2.400 to 15.440 kW. Due to new emission legislation like IMO3 in MARPOL Annex VI, customers are looking for alternative solutions for propulsion and power generation, which are able to operate like the well- known Diesel engines. The M46DF and M34DF Caterpillar Dual Fuel engines – also offered under the MaK trademark – are able to burn Natural gas ( LNG) and liquid fuels like Diesel, HFO or Crude oil. IMO3 emission limits are fulfilled with in gas operation and for liquid fuels an exhaust gas aftertreatment solution (SCR) is offered. Transient response is a key requirement for a lot of marine applications and these are not only emergency gensets with three step block loading. Supply vessels operate in a majority of time on low stand by power and require fast ramp up to high level of thrust. Even with Diesel engines this demands additional features like air injection into the charge air manifold. Gas engines are known to be slow in load response. This is mainly caused by air fuel ratio control depending on turbocharger inertia. Gas ignition is limited by upper and lower air fuel ratio limit, which leads to reduced rates in fuel ramp up. A faster speed governor would overfuel the combustion chamber. A Diesel engine would react with black smoke, but a gas engine would break down due to a mixture which is too rich. The M46DF and M34DF engines are equipped with a superior engine control. All controls are handled in a MIMOcontrol architecture. One speed governor controls three fuel systems (main Diesel fuel, ignition Diesel fuel and Gas admission). Due to this concept the load acceptance of Dual Fuel is on a level, which may be called “It runs like a Diesel”. This paper describes the engine concept and will show engine test results. A second aspect is the low load operation in Gas mode. Without additional technologies common gas engines run with a very lean mixture and emit increased amount of hydrocarbons. New technologies have been developed to allow unlimited engine operation with gas combustion. This paper describes the engine concept and will show engine test results of an IMO3- Dual Fuel engine optimized for marine applications with class leading load acceptance and low load operation.

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。Demand of dual fuel of liquid and gas is increased in a business of the standby gas turbine generator set. In this paper, technology in Niigata Power Systems regarding to dual fueled gas turbine system will be introduced. Following two main features will be described. The first one is the general description of the gas turbine package. The package mainly includes in a generator, a reduction gear, gas turbines and dual fuel supply units. The gas turbine components are also introduced. Especially, the configurations of the dual fuel injector and the combustor are focused. The combustor is single can type having simple configurations. The liquid fuel injector has both of a pressure atomizer for the pilot and an air blast atomizer for the main fuel injection. The gas injector with several spokes is inserted from over the liquid injector and the spokes are settled in just upstream of the swirler of the air blast atomizer. So, the flow pattern is not influenced by the fuel change. As the second one, engine operating results are shown. The exhaust gas emissions are compared with liquid and gas fuel. Emissions of carbon dioxide, nitrogen oxide and smoke are decreased by gas fuel use. Smoke emission is decreased 80 % from liquid to gas. Fuel control logics and trend data are focused in when fuel changes between liquid and gas. The fuel changes within extremely short time for overshooting recovery and with low fluctuations of engine speed are realized by fully electronic fuel control. It can choose both types of the fuels for engine start up. The trend data show that it can be quickly started up within 40 seconds in case of both fuels of liquid and gas. Here, purge clank time isn’t included in case of gas fuel choice. Finally, load dumping while fuel switching is discussed. Full load dumping during fuel changing is realized with low fluctuations of engine speed. And the overshooting recovery is very short time.

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。Yanmar has developed two types of marine gas engines which converted from proven marine diesel engine. These are a pure gas engines and dual fuel engines. A pure gas engine was developed as an auxiliary power supply, or the propulsion power of electric propulsion ship. The environmental impact material exhausted from this engine is few and thermal efficiency is high. A dual fuel engine was developed as the direct drive main propulsion engine. The feature of this engine is a high-power density and a high acceleration performance. A further reduction of nitrogen oxidation (NOx), sulfur oxidation (SOx) and particulate matter (PM) from an exhaust gas is international key policy problem from the viewpoints of the environmental protection. Green house gas including carbon dioxide emission control is also great problem from the view point of the global warming mitigation. The emission regulation of nitrogen oxides and sulfur oxides has been introduced to marine environment by IMO/MARPOL international convention for the marine environment in 2005, and, in addition, it is strengthened with the tier 2 restriction (2011) and the tier 3 restriction (2016) afterwards. Carbon content ratio in natural gas is less than that in other fossil fuels, and it contains sulfur not at all or little. That is why the natural gas can greatly reduce not only NOx, SOx, and PM but also the amounts of the CO2 exhaust. Therefore, installing natural gas engine in the ship would be effective to reduce environmental impact material from the ship. The air and fuel are mixed before the mixture is inhaled into, which is ignited in the gas engine. Because a homogeneous air-fuel mixture can control the highest combustion temperature by the density of the air-fuel mixture, the generation of the nitrogen oxide can be controlled. When the gas engine changes the output, a short time lag is necessary for the making changing of the air-fuel mixture. In the worst case, the engine runs into the knocking or missfire because the density of the air-fuel mixture significantly changes during this term. As for above marine gas engine mentioned before, the development technology of mixture concentration control during the load changing has been installed In this paper, we describe the mixture concentration control technology, and test results done by the new gas engines.

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。Off-Highway applications such as locomotives, mining trucks, inland waterway carriers, ferries or tug-boats are operated several thousand hours each year and require robust and cost efficient internal combustion engines. Today most of these applications are powered by diesel engines. But tightened emission regulations and limited oil reserves lead to more complex engines and higher costs. This leads to the question: are compressed (CNG) or liquefied (LNG) natural gas an alternative to diesel fuel? Looking at availability, infrastructure, costs and engine-out-emissions good arguments can be found to switch from Diesel to Gas in the future. The motivation is clear but the hurdles are high: availability of gas equipment (fuelling equipment, storage-tanks, engines), operational experience with gas (fuelling, servicing) or clear regulations. Within this paper we will provide a first more deep insight into the development of a 2 MW gas engine based on Series 4000 Diesel and Gas. It will be explained why this product is a promising concept for marine applications in particular. Design details like gas supply and injection System will be presented. Safety issues will be discussed and how these are designed on the engine. Results from the test bench will demonstrate the diesel-like performance while lowering the emissions. Finally there are a lot of challanges beside the engine which are ship design and gas fuelling. Having solved this, gas engines will have a great future in the market.

通过一台改装的6 缸增压直喷式柴油机，调整喷油正时实现燃烧相位的调节，在不同燃烧相位下开展了宽馏程燃油低温燃烧和排放特性的试验．结果表明：随初馏点的降低，燃料中汽油轻质馏分增加，燃料十六烷值降低，滞燃期延长，预混合气量增加，NOx 和碳烟排放均得到有效改善，但初馏点过低会导致HC 和CO 排放增加．随CA 50 的延后，碳烟和HC 排放增加，CO 和NOx排放降低．燃烧相位和宽馏程燃油特性相结合，可以在保证指示热效率的前提下，实现柴油机燃烧和排放的优化，达到同时降低NOx和碳烟排放的目的．

通过一台共轨柴油机，基于正庚烷/甲苯/正己烯混合物简化动力学机理耦合三维CFD 数值模型，模拟不同进气组分(O2、H2 和CO2)耦合喷油时刻对发动机工作过程的影响机理．研究表明：不同进气组分下，随喷油时刻提前，缸内活性自由基(OH、O)质量分数及其分布区域增大，NO 生成量增多．但随喷油时刻过度提前，燃烧始点反而推迟，燃烧放热速率、缸内燃烧压力与温度峰值降低，NO 也相应减少；相比其他进气组分，进气掺O2时缸内O自由基质量分数增大，碳烟(Soot)降低且喷油时刻对其影响较小；进气掺H2 时，缸内燃烧压力和温度峰值最高，OH 自由基质量分数及分布区域最大，Soot 随喷油定时提前大幅降低；进气掺CO2 时，缸内燃烧压力与温度峰值最低，OH 和O活性自由基最少，当喷油时刻提前超过24° CA BTDC时，燃油逐渐喷射到压缩余隙容积形成局部过浓区，C2H2和多环芳香烃芘(A4)生成量增多，Soot排放随喷油定时进一步提前明显升高．