柴油机碳烟排放浓度的预测

本文在国外有关碳烟生成和氧化过程基础研究所获得的理性认识基础上,建立了一个考虑到碳烟先兆物生成、成核、凝聚、集聚和氧化等过程的较为仔细的柴油机碳烟排放预测模型。该模型在110柴油机上作了初步验证,表明模型具有一定的预测能力。     

柴油机碳烟排放的数值模拟及试验研究

考虑碳烟粒子生成速率同时受控于涡团破碎速率和化学反应速率,提出一种输运控制率与碳烟氧化率混合控制模型进行碳烟计算,并用此模型对一台直喷式柴油机燃烧与排放生成过程进行了多维数值模拟。结果表明,计算模拟结果与试验测量结果吻合较好,且使用该模型能够预测柴油机研究样机的碳烟生成与氧化历程。     

基于机器学习的柴油机碳烟颗粒质量排放预测模型

基于SC7H涡轮增压柴油机试验台架,开展了非道路瞬态试验循环下的柴油机排放试验,研究了瞬态循环的工况对碳烟颗粒质量浓度的影响。收集与碳烟颗粒质量浓度相关的各类传感器数据,构建一个大型的柴油机碳烟排放数据集。构建LGB梯度树模型和循环神经网络模型,采用数据集对它们进行训练,然后采用自学习算法对两种模型进行融合,获得一个更高准确度的预测碳烟质量排放融合模型。预测与实测结果的比较表明,构建的融合模型能较为准确地预测柴油机排放的即DPF入口的碳烟质量浓度实时变化,为柴油机后处理过程中碳载量的准确计算以及控制策略的开发提供参考。     

柴油机碳烟颗粒在NO气氛下的催化氧化研究

围绕柴油机碳烟颗粒在NO气氛下的催化氧化问题进行相关的实验研究。通过稀土氧化物氧化铈和氧化镧分别负载硝酸盐制备了实验用催化剂,并在催化剂和碳烟颗粒"松接触"情况下,研究了在NO背景下对碳烟颗粒催化氧化过程,实现了在NO背景下对碳烟颗粒催化氧化;实验结果还显示,采用复合性稀土氧化物更能促进碳烟颗粒催化氧化,更有利于同时解决柴油车排放过程中产生的PM和NOx,从而为了开发高性能柴油机用催化剂提供了重要的实验基础。     

柴油机直通式碳烟净化器结构和尺寸优化

EX-20直通式碳烟净化器具有高抗热冲击性能和较好的机械性能。为提高其装车后的使用耐久性,有必要进一步改善净化器滤芯的机械性能。本文通过优化滤芯的结构参数和尺寸参数,在提高滤芯机械强度的同时,较好在兼顾其碳烟过滤效率和排气背压。     

碳烟氧化模型的研究及在车用柴油机中的计算应用

提出了一个基于平均反应率的碳烟氧化模型,将其应用于柴油机数值模拟中,并结合试验方法研究了后喷射对碳烟排放的影响。将Hiroyasu碳烟生成模型和文中提出的碳烟氧化模型耦合在CFD源程序中构建多维模型,利用数值解析的手段,根据不同的后喷射方案计算柴油机碳烟的生成和氧化历程,并结合试验数据分析后喷射影响碳烟氧化的各种因素。研究结果表明,采用碳烟氧化模型和试验方法能真实反映柴油机碳烟的生成和氧化历程以及后喷射对碳烟排放的影响规律。     

柴油机燃用二甲醚及采用排气再循环同时降低碳烟和ＮＯx排放的研究

本文对单缸直喷柴油机燃用二甲醚及采用排气再循环同时降低碳烟和ＮＯx排放进行了研究，结果表明，与燃用柴油相比，发动机燃用二甲醚可以实现无烟燃烧，ＮＯx降低３０％，未燃碳氢和ＣＯ排放有所下降，采用排气再循环（ＥＧＲ）在不增加未燃碳氢、ＣＯ和ＣＯ２、恶性发动机热效率的前提下进一步降低ＮＯx排放。     

柴油机燃用二甲醚及采用排气再循环同时降低碳烟和ＮＯx排放的研究

本文对单缸直喷柴油机燃用二甲醚及采用排气再循环同时降低碳烟和ＮＯx排放进行了研究，结果表明：与燃用柴油相比，发动机燃用二甲醚可以实现无烟燃烧，ＮＯx降低３０％，未燃碳氢和ＣＯ排放有所下降。采用排气再循环（ＥＧＲ）在不增加未燃碳氢。     

改善柴油机燃烧及排放的措施

介绍了改善柴油机燃烧、降低柴油机排放的几种机内控制及排气后处理的有效措施。     

柴油机低温启动的影响因素和改善措施

分析研究了影响柴油机低温启动的主要因素，结果发现，在低温情况下的启动力矩减小、阻力矩增大和着火困难是导致柴油机低温启动困难的主要原因，并提出了相应的改善措施。     

某型柴油发电机组测试控制系统的研制

论文中对某型柴油发电机组测试控制系统所实现的主要功能、技术指标、测试系统主要组成、工作原理作了系统论述,该测试控制系统可以解决柴油发电机组在大修中的测试控制问题,提高维修效率,降低维修成本。该系统的研制对其他类似柴油发电机组的测试和控制有一定借鉴作用。     

轴瓦损伤的原因及选配

对发动机轴瓦损伤产生的原因及危害进行了分析。详细介绍了轴瓦的选配方法和注意事项，对于实际工作中，保证轴瓦维修质量有重要参考价值。     

谈135系列柴油机调速器润滑油面静态自动显示器的研制

分析了135系柴油机调速器内机油量无自动显示装置带来的问题，针对这一问题进行了论证和研制；介绍了该显示器工作原理、关键技术、特点及其使用维护。     

Impact of SME blended fuel combustion on soot morphological characteristics in a diesel engine

The soot morphological study and NOx emissions of soybean oil methyl ester (SME) in a passenger diesel vehicle were investigated experimentally. The soot morphological characteristics were conducted at various injection pressures, engine speeds and engine loads. Soot sampling and image processing analysis with a scanning electron microscope (SEM) were used to investigate the influence on particulate morphologies. The dimensions of average primary particles and the size of the radius of gyration were gradually decreased as injection pressures increased at all operating engine conditions. The average radius of gyration was increased with increasing engine load, while the average primary particle size decreased. NOx emissions were gradually increased with the increasing injection pressure at all operating engine conditions.     

Improved theoretical modeling of a cyclone separator as a diesel soot particulate emission arrester

Particulate matter is considered to be the most harmful pollutant emitted into air from diesel engine exhaust, and its reduction is one of the most challenging problems in modern society. Several after-treatment retrofit programs have been proposed to control such emission, but to date, they suffer from high engineering complexity, high cost, thermal cracking, and increased back pressure, which in turn deteriorates diesel engine combustion performance. This paper proposes a solution for controlling diesel soot particulate emissions by an improved theoretical model for calculating the overall collection efficiency of a cyclone. The model considers the combined effect of collection efficiencies of both outer and inner vortices by introducing a particle distribution function to account for the non-uniform distribution of soot particles across the turbulent vortex section and by including the Cunningham correction factor for molecular slip of the particles. The cut size diameter model has also been modified and proposed by introducing the Cunningham correction factor for molecular slip of the separated soot particles under investigation. The results show good agreements with the existing theoretical and experimental studies of cyclones and diesel particulate filter flow characteristics of other applications.     

Effects of split injection,oxygen enriched air and heavy EGR on soot emissions in a diesel engine

The effects of split injection, oxygen enriched air, and heavy exhaust gas recirculation (EGR) on soot emissions in a direct injection diesel engine were studied using the KIVA-3V code. When split injection is applied, the second injection of fuel into a cylinder results in two separate stoichiometric zones, which helps soot oxidation. As a result, soot emissions are decreased. When oxygen enriched air is applied together with split injection, a higher concentration of oxygen causes higher temperatures in the cylinder. The increase in temperature promotes the growth reaction of acetylene with soot. However, it does not improve acetylene formation during the second injection of fuel. As more acetylene is consumed in the growth reaction with soot, the concentration of acetylene in the cylinder is decreased, which leads to a decrease in soot formation and thus soot emissions. A combination of split injection, a high concentration of oxygen, and a high EGR ratio shows the best results in terms of diesel emissions. In this paper, the split injection scheme of 75.8.25, in which 75% of total fuel is injected in the first pulse, followed by 8°CA of dwell time, and 25% of fuel is injected in the second pulse, with an oxygen concentration of 23% in volume and an EGR ratio of 30% shows a 45% reduction in soot emissions, with the same NOx emissions as in single injection.     

Pressure drop and heat transfer of catalyzed diesel particulate filters due to changes in soot loading and flow rate

When soot particles are loaded in a diesel particulate filter, it causes increase in back pressure of the exhaust system. To minimize this pressure drop due to DPF, the filter needs to be regenerated after a certain amount of soot has been accumulated. It is crucial to estimate the correct amount of soot that has been accumulated by measuring the differential pressure. It is also important to understand changes in pressure drop due to flow rate variations of the exhaust gas, since the pressure drop would be influenced by the exhaust flow rate as well as the amount of soot. Furthermore, the heat transfer characteristics of the catalyzed diesel particulate filter (CDPF) are another major issue, as the filter is occasionally exposed to high temperature gas. This study presents the characteristics of pressure drop according to the variation of soot loading and the mass flow rate in CDPF. In addition, heat transfer characteristics in the filter was investigated when a high temperature gas flows into the CDPF. Tests were performed in several CDPF samples having varying amounts of catalyst coating. Experimental results indicate that rig-based experiments are useful in understanding the characteristics of pressure drop in the CDPF. In the cake filtration region, a pressure drop has a proportional relationship according to soot loading and mass flow rate. It was found that an increased catalyst coating may lead to enhanced convective heat transfer.     

492Q发动机油底壳实验振动模态分析

进行发动机油底壳实验振动模态分析，对随机减量技术及ITD法在内燃机领域的应用展开了一些研究，其结果具有可信性。