Combination of biodiesel-ethanol-diesel fuel blend and SCR catalyst assembly to reduce emissions from a heavy-duty diesel engine

In this study, the efforts to reduce NOx and particulate matter （PM） emissions from a diesel engine using both ethanol-selective catalytic reduction （SCR） of NOx over an Ag/Al2O3 catalyst and a biodiesel-ethanol-diesel fuel blend （BE-diesel） on an engine bench test are discussed. Compared with diesel fuel, use of BE-diesel increased PM emissions by 14% due to the increase in the soluble organic fraction （SOF） of PM, but it greatly reduced the Bosch smoke number by 60%-80% according to the results from 13-mode test of European Stationary Cycle （ESC） test. The SCR catalyst was effective in NOx reduction by ethanol, and the NOx conversion was approximately 73%. Total hydrocarbons （THC） and CO emissions increased significantly during the SCR of NOx process. Two diesel oxidation catalyst （DOC） assemblies were used after Ag/Al2O3 converter to remove CO and HC. Different oxidation catalyst showed opposite effect on PM emission. The PM composition analysis revealed that the net effect of oxidation catalyst on total PM was an integrative effect on SOF reduction and sulfate formation of PM. The engine bench test results indicated that the combination of BE-diesel and a SCR catalyst assembly could provide benefits for NOx and PM emissions control even without using diesel particle filters （DPFs）.

Influence of Pre-injection Control Parameters on Main-injection Fuel Quantity for an Electronically Controlled Double-valve Fuel Injection System of Diesel Engine

A simulation model of an electronically controlled two solenoid valve fuel injection system for a diesel engine is established in the AMESim environment.The accuracy of the model is validated through comparison with experimental data.The influence of pre-injection control parameters on main-injection quantity under different control modes is analyzed.In the spill control valve mode,main-injection fuel quantity decreases gradually and then reaches a stable level because of the increase in multi-injection dwell time.In the needle control valve mode,main-injection fuel quantity increases with rising multi-injection dwell time;this effect becomes more obvious at high-speed revolutions and large main-injection pulse widths.Pre-injection pulse width has no obvious influence on main-injection quantity under the two control modes;the variation in main-injection quantity is in the range of 1 mm3.

Use of Diesel Engine and Surface-Piercing Propeller to Achieve Fuel Savings for Inshore Fishing Boats

Fishing is a major local industry in Malaysia, particularly in rural areas. However, the rapidly increasing price of fuel is seriously affecting the industry＇s viability. At present, outboard petrol engines are the preferred choice for use in small-scale fishing boats because they deliver the advantages of high speed and low weight, they are easy to install, and they use minimal space. Petrol outboard engines are known to consume a greater amount of fuel than inboard diesel engines, but installing diesel engines with conventional submerged propellers in existing small-scale fishing boats is not economically viable because major hullform modifications and extra expenditure are required to achieve this. This study describes a proposal to enable reductions in fuel consumption by introducing the combined use of a diesel engine and Surface-Piercing Propeller （SPP）. An analysis of fuel consumption reduction is presented, together with an economic feasibility study. Resulting data reveal that the use of the proposed modifications would save 23.31 liters of fuel per trip （40.75%） compared to outboard motors, equaling annual savings of RM 3962 per year.

A Fuel Economy Study in Heavy Duty Diesel Engine Lubricants

Internal combustion engines′ fuel economy is an important role for engine designers,engine manufacturers over the past 30 years,especially passenger car motor oils.In heavy duty diesel engine,over the past 20 years,fuel economy has in some cases been sacrificed for exhaust gas emission optimizations.Now,Heavy Duty Automotive and the related industries have strong interest in fuel economy and the lubricants.It is driven by competitive market forces as well as government mandates and new emission regulations.Japan was the first country in the world to establish and implement heavy duty trucks and buses fuel economy standards.Other countries also have followed either by establishing direct fuel economy standards or greenhouse gas(GHG) emissions standards which are directly tied to fuel economy.This paper is discussing that heavy duty diesel engine lubricants can contribute on fuel economy.The contribution of various aspects of engine oil formulations on fuel economy will be discussed such as lubricant viscosity grade,lubricant additives and friction modifiers.In this paper,the evaluation discussions are based on fuel economy measurements in some bench tests,standardized laboratory engine tests and field tests.

Endurance Test of Biodiesel Fueled Tractor Engine

A diesel engine for tractor was tested for 250 hours of durability with biodiesel fuel of 100%. An engine test cycle was designed based on the ISO test code of off-road vehicle. Eight test conditions, combination of three engine speeds and eight engine loads, were applied to the engine endurance test, and the engine was operated for eight hours in a day. Power output, fuel consumption rate, exhaust gas quality and particulate matter （PM） were measured and discussed. For the extensive 250 hours of the tractor diesel engine endurance test no significant changes of power output, fuel consumption rate, exhaust gas quality and PM were monitored and authors could not find any difference in the engine patterns of the two fuels of BDF100 and light oil. During all the engine endurance test conditions, no abrupt stopping was encountered but because of temperature down by the cold season the endurance test could not carried out for some periods. PMs were collected and the average F＇M was 0.027 g/kw which was far below than Tier 4 diesel engine PM of 0.3 g/kw h defined by US EPA PM of the diesel engine clas,;. Overall even 100% biodiesel can be an alternative fuel for light oil for diesel engine operation with some considerations for cold sea：son use.

An Electronic Unit for Improving Fuel Combustion in a Diesel Engine

A new method using Ozone to improve fuel combustion resulting in fuel saving and pollution reduction for diesel engine has been put forward in this paper. The method features non destructive fuel saving and anti-knock nature improvement. The experiment shows that, compared with those of the original engine, the fuel saving rate is up to 1.7%-3.3%, and the exhaust pollution reduction rate is 3.0%-6.8, thus may lead to a good comprehensive benefit in economic, social and ecological aspects.

Utilizing Artificial intelligence to identify an Optimal Machine learning model for predicting fuel consumption in Diesel engines

This paper describes the utilization of artificial intelligence (AI) techniques to identify an optimal machine learning (ML) model for predicting dodecane fuel consumption in diesel combustion. The study incorporates sensitivity analysis to assess the impact levels of various parameters on fuel consumption, thereby highlighting the most influential factors. In addition, this study addresses the impact of noise and implements data cleaning techniques to ensure the reliability of the obtained results. To validate the accuracy of the predictions, the study performs several metrics and validation process, including comparisons with computational fluid dynamics (CFD) results and experimental data. Comprehensive comparisons are made among neural networks (NN), random forest regression (RFR), and Gaussian process regression (GPR) models, taking into account the complexity associated with fuel consumption predictions. The findings demonstrate that the GPR model outperforms the others in terms of accuracy, as evidenced by metrics such as mean absolute error (MAE), mean squared error (MSE), Pearson coefficient (PC), and R-squared (R2). The GPR model exhibits superior predictive ability, accurately detecting and predicting even individual data points that deviate from the overall trend. The significantly lower absolute error values also consistently indicate its higher accuracy compared with the NN and RFR models. Furthermore, the GPR model shows a remarkable speedup, approximately 1.7 times faster than traditional CFD solvers, and physically captures the momentum and thermal characteristics in a surface field prediction. Finally, the target optimization is assessed using the Euclidean distance as a fitness function, ensuring the reliability of predicted data.

Experimental Investigation on Diesel Engine Performance Using Nano Air-Bubbles Mixed into Gas Oil

The authors studied diesel combustion improvement with a reformed fuel that mixed nano air-bubbles by using an EMNB （ejector-type micro-nano bubbler）. The EMNB performs adequately and is smaller （20 mm diameter, 34 mm length） than other micro-nano bubblers. It is quite possible to install it in an actual engine. An experiment was performed using a single cylinder engine with a dish or square shaped combustion chamber cavity, and in order to compare the engine speed change, we also used a four cylinder engine with a turbo-charger. The results showed that an improvement in specific fuel consumption, a decrease in the density of the exhaust smoke and an improvement in charging efficiency etc. were achieved by mixing nano bubbles into gas oil under most conditions. It is confirmed that combustion was promoted and improved by a physical and chemical action through mixing the nano bubbles into gas oil.

Effects of Hydrogen Addition on Power and Emissions Outputs from Diesel Engines

Energy efficiency and environmental impact have become dominant topics in internal combustion engines development. Among many strategies to improve power and emissions outputs from diesel engines is the partial mix of hydrogen and air as fresh charge components to form extremely lean and homogenous mixture, which resist the spontaneous combustion, while diesel fuel is injected directly inside combustion chamber using the conventional fuel injection systems. This contribution presents an analytical and experimental investigation for the effects of adding hydrogen on diesel engines power output and the reduction of emissions. Parametric analysis is used based on lamped parameters modeling of intake manifold to estimate in cylinder trapped charge. The fuel energy flow to engine cylinders is compared for a range of loads and concentrations to simulate relevant case studies. Diesel fuel reduction for significant range of part-load operation can be achieved by introducing hydrogen, along with power improvement emission reductions are affected positively as well. This is achievable without compromising the engine maximum efficiency, given that most engines are operated at small and part-load during normal driving conditions, which allow for introducing more hydrogen instead of large quantities of excess air during such operation conditions that also can be further improved by charge boosting.

Characteristics of Particulate Matter Emissions for Low-Sulfur Heavy Oil Used in Low-Speed Two-Stroke Diesel Engines of Ocean-Going Ships

In this work,particulate matter(PM) emissions from a large two-stroke,low-speed marine diesel engine were investigated when the engine was operated with low-sulfur heavy fuel oil(HFO) at various loads.Particle samples were collected in situ from the engine exhaust to determine the detailed physical and chemical properties.The nanostructure and morphology of the nanoparticles were analyzed using transmission electron microscopy images(TEM).The results show that volatile organic carbon(OC) accounts for more than 80% in the HFO particles and leads to an increase in particle size.The thermodynamic conditions of a low-speed engine favor the behavior of capturing the soluble organic components.A large number of spherical char HFO particles with aerodynamic diameters of 0.2 μm-0.5 μm and a suspected inner metal core were detected.The two peak aerodynamic diameters of the HFO nanoparticles are 15 nm and 86 nm.The morphological differences among the HFO nanoparticles in varied engine conditions represent the formation process from primary nascent particles to mature graphitized particles caused by thermodynamics.The above study will be valuable for understanding the characteristics of PM emissions from low-sulfur HFO to achieve the ship PM emissions reduction target.

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition(CI)engine.Engine operational parameters,including engine load(0.6,0.7,and 0.8 MPa indicating the mean effective pressure(IMEP)),the exhaust gas recirculation(EGR)rate(0%,10%,20%,and 30%),and the fuel injection timing(–20,–15,–10,and–5°crank angle(CA)after top dead center(ATDC))were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions.In comparison to diesel fuel,RP-3 jet fuel shows a retarded heat release and lagged combustion phase,which is more obvious under heavy EGR rate conditions.In addition,the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions.As a result,RP-3 jet fuel features a longer ignition delay(ID)time,a shorter combustion duration(CD),and an earlier CA50 than diesel fuel.The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency(ITE)compared to diesel fuel,but the ITE difference becomes less noticeable under large EGR rate conditions.Compared with diesel fuel,the nitrogen oxides(NOx)emissions of RP-3 jet fuel are higher while its soot emissions are lower.The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.

A Numerical Investigation on the Effects of Intake Swirl and Mixture Stratification on Combustion Characteristics in a Natural-Gas/Diesel Dual-Fuel Marine Engine

Natural gas/diesel dual-fuel combustion strategy has a great potential to reduce emissions for marine engines while the high fuel consumption is the major problem.Pre-chamber system is commonly employed as the ignition system on large-bore dual-fuel marine engines especially under lean-burn condition,due to its advanced ignition stability and engine efficiency.However,the ignition and combustion mechanism in such dual-fuel pre-chamber engine is still unclear and the effects of in-cylinder swirl flow and mixture stratification on combustion require further investigation specifically.This paper numerically studied the detailed ignition mechanism and combustion process in a marine engine equipped with a pre-chamber ignition system,and revealed the flame development process in main chamber.Moreover,the effects of mixture stratification and swirl ratio on the combustion rate and further engine thermal efficiency are investigated under decoupled condition.The results mainly show that the jet flame develops along the pre-chamber orifice centerline at the initial stage and premixed combustion play an important role,while after that,heat release zone only exist at flame surface,and premixed flame propagation controls the combustion process.In addition,with higher swirl ratio the combustion rate increases significantly due to the wider ignition area.Mixture stratification degree plays a role in accelerating the combustion,either too high or too low stratification degree reduce the combustion rate,while a moderate stratification increases the combustion rate.And appropriate stratification degree by verifying the gas injection parameters can reduce fuel consumption in 0.3%.

大缸径柴油机燃烧系统优化模拟

为提高某缸径200 mm船用发电柴油机的燃油经济性,本文设计了活塞燃烧室和燃油喷射系统的升级方案并进行了模拟优化。升级方案提高了压缩比和燃油喷射压力,采用大径深比浅ω燃烧室配合158°喷油夹角喷油嘴。对不同方案下发动机的缸内工作过程进行了计算流体力学模拟,计算了高压指示功和放热率相位,分析了缸内温度、反应过量空气系数和速度分布及演化。模拟结果表明:升级方案能够提高发动机热效率。增加喷孔数并减小孔径,可以在保持NOx排放基本不变的条件下提高高压指示功4.5%,降低碳烟排放约60%。采用“平顶”浅ω燃烧室与158°喷油夹角喷雾配合,油气混合气快速进入余隙并形成逆时针的漩涡流动,能够加速油气混合和燃烧过程,提高热效率。

不同海拔下氢气/柴油双燃料发动机燃烧与排放特性研究

基于大气模拟综合测试系统,模拟0 m、1 000 m和2 000 m海拔的大气压,对不同海拔下氢气/柴油双燃料发动机燃烧与排放特性进行研究。研究结果表明:不同海拔下,随着氢气替代率增加,预混合燃烧增强,缸内燃烧速度加快,缸压峰值升高,其对应相位提前;碳烟和CO排放先下降后上升,NO_(x)排放增加,CO_(2)排放减少。随着海拔上升,过量空气系数减小,有效热效率降低。转速为1 600 r/min时,随着海拔高度升高,预混合燃烧减弱,发动机缸压峰值下降,其对应相位推迟;CO排放最低时,与0 m海拔比较,海拔上升至1 000 m、2 000 m,碳烟排放分别增加44.44%和127.78%,CO排放增加8.95%和16.86%,CO_(2)排放增加4.34%和16.86%,碳烟和CO_(2)排放增幅随海拔增加而上升。转速为3 000 r/min时,随着海拔高度上升,缸压峰值略有升高,缸压峰值对应相位提前,预混合燃烧增强;碳烟、NO_(x)、CO和CO_(2)排放升高,排放增幅随海拔升高而增大。与海拔0 m比较,当碳烟排放最低时,海拔上升至1 000 m、2 000 m,碳烟排放分别升高18.67%和56.04%,NO_(x)排放分别上升14.78%和38.40%,CO_(2)排放分别升高7.29%和15.80%;CO排放最低时,海拔上升至1 000 m、2 000 m,CO排放分别上升24.53%和62.87%。

极寒条件下含氧燃料对柴油机冷起动特性的影响

针对柴油机存在低温冷起动困难甚至无法起动的问题,基于起动/发电机集成一体化技术柴油机,在高原低温发动机冷起动试验舱,研究-50号柴油A0(氧质量分数为0%)、A1(氧质量分数为2.05%)和A2(氧质量分数为4.40%)燃料在-43℃下对柴油机冷起动过程的影响和燃烧特性分析.结果表明:相比A0纯柴油,燃用A1、A2含氧燃料起动时间分别缩短了36.64%和42.71%;起动累计油量分别降低47.8%和60.6%;怠速运行前60 s内转速波动率分别降低25.3%和43.8%.燃用燃料氧质量分数越高,起动燃烧首循环的缸内压力、燃烧放热率、缸内燃烧温度和缸内压力升高率峰值越高,且燃烧重心前移,燃烧持续期越短;起动转速上升过程循环数越少,平均最大缸内压力越大,起动过程燃烧稳定性越好.

引燃柴油量对双燃料发动机循环变动的影响

为了降低重型高压共轨柴油机燃用LNG-柴油的燃烧循环变动,优化引燃柴油量控制,通过双燃料发动机试验台架,研究了在最大转矩转速1600r/min,功率输出为73kW工况下,随引燃柴油喷油量的增加,峰值压力、峰值压力升高率、平均指示压力循环变动的变化趋势。研究结果表明,随引燃柴油量的增加,双燃料发动机的峰值压力、峰值压力升高率和平均指示压力的循环变动趋势相同,它们的均值均增大,标准差减小,循环分布集中,循环变动系数降低。在不导致爆震燃烧的前提下,适当增大引燃柴油量,能够改善双燃料发动机的燃烧稳定性。

EGR技术对生物柴油混合燃料发动机性能的影响研究

为缓解柴油掺烧生物柴油导致的NO_(x)排放过高问题,将4190ZLC船用中速柴油机作为试验台架,通过AVL_FIRE软件建立燃烧室模型,并验证该模型准确性。设置生物柴油掺混比0~40%等4组变量,EGR率0~12.5%等4组变量,进行柴油机燃烧、性能和排放分析。结果表明,掺烧适量生物柴油能够降低柴油机缸内温度,降低Soot排放,但同时会导致NO_(x)排放明显升高;EGR的引入能够实现低温燃烧,显著降低NO_(x)排放,但EGR率过高会增加Soot排放。生物柴油掺混比B40、EGR率12.5%组合NO排放比原机降低47.7%,Soot排放质量分数比原机降低98.13%。本文结果将为柴油掺混生物柴油燃烧并结合EGR技术提供一定的研究方向。

DPF炭烟和灰分加载对不同增压系统柴油机性能的影响

基于某直列6缸增压柴油机试验台架,构建了柴油机+DPF的一维热力学仿真模型,研究了DPF炭烟和灰分加载对不同增压系统柴油机性能的影响。研究结果表明,DPF炭烟和灰分加载会导致单级增压(1TC)和二级增压(2TC)柴油机排气背压升高,进气充量降低,从而导致动力性下降,有效燃油消耗量升高,NO x排放量下降,soot排放量增加。炭烟因其深床炭烟层和较低的渗透率有利于捕集颗粒,提高了DPF捕集效率;而灰分由于其存在灰分堵头降低了孔道有效过滤长度,导致DPF捕集效率下降。DPF炭烟和灰分加载导致1TC柴油机扭矩和燃油消耗率在1000 r/min分别下降22.8%和29.6%,在2200 r/min分别下降2.1%和2.2%;而2TC柴油机扭矩和燃油消耗率在1000 r/min分别下降6.7%和7.1%,在2200 r/min分别下降10.7%和11.9%。二级增压可以降低DPF炭烟和灰分加载对柴油机性能的影响。

基于三维建模的喷油器流量系数在线测试

该文提出一种柴油机喷油器喷嘴流量系数在线测量方法。通过实验探究了燃油系统内部压力波的演化及传递过程并基于实验数据验证了算法的准确性;基于黎曼不变量理论将燃油系统内部复杂的压力变化过程简化为黎曼波的演化及传递过程,并建立了喷油过程中喷油器入口压力与流量系数的数学关系;根据燃油系统结构提出了一种基于喷油器入口压力信号的黎曼波解耦方法,提高了算法的使用范围。该文搭建了流量系数测量平台,通过实验验证了所提出方法有较高精度。

基于ANSYS的复式膨胀节强度和轴向刚度有限元分析

通过ANSYS有限元分析,研究了复式膨胀节在同时受内压及轴向位移时的强度和轴向刚度.建立了复式膨胀节的二维轴对称模型,并考虑了非线性对复式膨胀节的影响,将分析结果与EJMA工程近似法计算结果进行对比,表明ANSYS有限元结果更接近实际情况,采用工程近似法分析复式膨胀节时存在一定误差.