低排放柴油机机油消耗控制技术探讨

降低低排放柴油机的机油消耗是控制颗粒物排放的前提。本文主要阐述了柴油机缸内机油消耗的途径、影响因素及控制技术。     

基于国6排放法规要求的活塞环优化设计

基于国6排放法规要求以及国家碳达峰碳中和政策,分析了整车排放状况与发动机活塞环设计的关系,提出通过采用更先进的活塞环设计技术来解决整车在同等排放下提升最高限速的问题。针对发动机活塞系统活塞环的设计现状,提出活塞环的优化设计方案,并运用AVL-Excite Piston&Rings软件进行模拟仿真,分析活塞环优化前后的发动机机油消耗对比情况。通过整车排放验证和发动机台架验证数据发现,实施活塞环的优化方案可有效降低发动机的机油消耗水平,降低颗粒物(Particulate Matter,PM)排放水平,从而提高整车限速值。     

柴油机机油耗高的排查改进及控制

介绍了柴油机机油消耗高的排查方法,通过对机油消耗率影响因素的分析,进行试验和测量,提出了设计改进措施和质量控制措施,使柴油机机油消耗率得到了进一步降低,同时也促进了柴油机的环保排放达标。     

曲轴箱通风对GDI汽油机微粒排放的影响

缸内直喷(GDI)汽油机微粒生成是由于雾化时间短及局部混合气过浓;同时,因为机油不可避免地参与燃烧也导致微粒排放增加.曲轴箱通风中未被油气分离器分离的机油蒸气占据机油消耗量比重较大,理论上这部分机油参与燃烧所产生的颗粒物对发动机最终的微粒排放影响也相应较大.因此,笔者在国产4G75缸内直喷汽油机上使用EEPS测定不同机油消耗条件下微粒排放特性,研究不同曲轴箱通风状态下未分离机油对GDI发动机微粒排放影响规律.结果表明:未被分离的机油消耗量增加导致微粒迅速升高,尤其在怠速工况下显著影响微粒生成质量;随发动机转速逐渐升高,机油消耗量对微粒生成的影响明显降低.     

气缸套内孔平台珩磨与平台珩磨网纹的检测

一、概述 珩磨可以分为一般珩磨和平台珩磨。平台珩磨网纹是使缸套内孔获得最小的几何形状偏差和最好的尺寸精度,从而优化活塞环和气缸套工作表面的这一摩擦副的工作性能,降低发动机的磨合时间和发动机的机油消耗。 为了提高发动机的可靠性和经济性,必须特别注重气缸套的表面加工质量以及它们对发动机的运转性能的影响。气缸套内孔的尺寸精度和几何精度影响发动机的机油消耗和缸孔的气密性;工作表面的轮廓形状、结构以及金属材料边界层的金相组织变化和粗糙度的大小,影响发动机的磨合时间、活塞环工作滑动性能、机油消耗和抗擦伤能力。网纹角度影响发动机的机油消耗。     

汽油机机油消耗量的试验与分析

润滑油对发动机有非常重要的作用，发动机中影响机油消耗的因素也很多。本文针对不同的缸盖护罩、活塞、二道气环和油环背压，在电控汽油机上进行了机油消耗量的试验和分析。试验结果表明：总机油消耗主要包括活塞部分机油消耗和强制通风口机油消耗两部分，其中活塞部分机油消耗占总机油消耗的90％以上；改进型缸盖护罩能有效冷凝机油蒸汽，降低机油的蒸发消耗；对二道气环的改进能减少活塞环的磨损，并提高刮油效果；确保活塞与气缸贴合的更好，能有效阻止窜气的发生；油环背压的增加能够改善刮油效果，但由于同时增加了活塞环的磨损，在实验后期机油消耗量反而增加。     

降低机油耗的途径和措施

本文阐述了发动机机油消耗的机理，列述了降低缸套内壁网纹的粗糙度、保证机体缸孔的圆度、控制曲国同箱压力、选择合适的活塞环开口间隙和油环的面压等可有效降低发动机机油耗的措施。     

发动机机油燃油消耗百分比测量不确定度评定

本文通过对CA6XX发动机机油消耗量试验过程中引入测量不确定度的来源,进行识别和标准测量不确定度分量的评定,以及标准不确定度的合成、扩展不确定度的计算,阐述了发动机机油燃油消耗百分比的测量不确定度的评定方法。     

气缸套内孔平台珩磨与检测

平台珩磨是根据发动机的工作特性及磨合机理，对气缸套内孔珩磨质量提出的要求，使气缸套内孔获得最小的几何形状偏差、最佳的尺寸精度，让活塞环与气缸套工作表面具有良好的滑动性能且能保持油膜稳定，优化活塞环与缸套摩擦副的工作性能，降低发动机的磨合时间和机油消耗。     

降低机油耗的途径和措施

本文阐述了发动机机油消耗的机理,列述了降低缸套内壁网纹的粗糙度、保证机体缸孔的圆度、控制曲轴箱压力、选择合适的活塞环开口间隙和油环的面压等可有效降低发动机机油耗的措施.     

A novel biomass lubricant filter and its effect on gasoline engine emissions and fuel economy

With the increasing number of light-duty passenger car, a large amount of waste engine oil was produced yearly which has polluted the environment and wasted fossil resources. Extend engine oil drain interval and reduce its effect on engine emission is of great importance. In this paper, a kind of modified-sawdust engine oil filter was developed and the study focus on its effect on the emission characteristics and fuel consumption rate of spark ignite gasoline engine. This modified-sawdust engine oil filter was also compared with common oil filter. The tests were performed in four-cylinder direct injection gasoline engine at six different typical operating conditions. Various tests were proceed including the exhaust emissions measurement of nitrogen oxides (NOx), carbon monoxide (CO) and hydrocarbons (HC) as well as the fuel consumption rate measurement. The effect of engine oil change on engine emission and fuel consumption rate were also studied. Impurity element content of waste oil and kinetic viscosity were measured before and after modified oil filter was used. The results show that relative to common oil filter, the modified-sawdust oil filter has 0.4–2.1%, 3.7–7.5%, 1.6–13.3% decrease for CO, HC, NOx emissions, respectively. In addition, it significantly reduces oil consumption, and the three major emission species (CO, HC and NOx) was also reduced when fresh engine oil was adopted. These results indicate that the use of modified-sawdust oil filter is an effective choice to improve gasoline engine emission and fuel economy.     

基于容积法的发动机油耗仪测控系统的设计

针对传统油耗仪可靠性差、测量精度低的问题,设计了一种新型发动机油耗仪测控系统.该油耗仪基于容积法测量原理,通过在测量容器中加入浮球,利用浮球遮光来检测液面信号的方法,有效地提高了传统油耗仪的测量精度和可靠性.     

油耗测量系统控制部分的设计

目前,安装电喷发动机油耗测量仪的传感器时都要拆动燃油管路,费时也浪费燃油,十分不便。论文设计了一种不用油耗传感器的电喷发动机油耗测量仪器,该仪器充分利用了电喷发动机电脑控制的精确供油信息,将各缸的供油信息进行采集、标定、运算后输出测量时间内的累计油耗和小时耗油量。安装时无需拆动燃油管路,无燃油损失,且测量方便、快捷。本文主要就油耗测量系统的控制部分作了介绍。     

油耗测量系统控制部分的设计

目前，安装电喷发动机油耗测量仪的传感器时都要拆动燃油管路，费时也浪费燃油，十分不便。论文设计了一种不用油耗传感器的电喷发动机油耗测量仪器，该仪器充分利用了电喷发动机电脑控制的精确供油信息，将各缸的供油信息进行采集、标定、运算后输出测量时间内的累计油耗和小时耗泸量。安装时无需拆动燃油管路，无燃油损失，且测量方便、快捷。本文主要就油耗测量系统的控制部分作了介绍。     

乳化油在1135柴油机上的应用

乳化油作为一种代用燃料，既可以减少燃料消耗又可以控制排放，作者采用HLB值法筛选和复配乳化剂，在1135柴油机上进行了该乳化柴油的台架试验，结果表明该型乳化油与0＃柴油相比平均节同率不低于10％，主要排放物NOx、碳烟降低40％以上，同时排温和最高燃烧压力降低。还分析了影响乳化油燃烧效果的两个主要因素：含水率和喷油提前角。     

发动机运行工况对机油耗影响的试验研究

本文利用差压式机油耗测量系统在6135ZLCa柴油机上进行了大量试验研究，得到了机油消耗量随工况变化的试验曲线，结果表明发动机机油耗与运行工况有密切关系。本文还从机油消耗途径的角度出发，解释分析了转速及负荷对机油耗的影响。     

Determination of TDC in internal combustion engines by a newly developed thermodynamic approach

In-cylinder pressure analysis is nowadays an indispensable tool in internal combustion engine research & development. It allows the measure of some important performance related parameters, such as indicated mean effective pressure (IMEP), mean friction pressure, indicated fuel consumption, heat release rate, mass fraction burned, etc. Moreover, future automotive engine will probably be equipped with in-cylinder pressure sensors for continuous combustion monitoring and control, in order to fulfil the more and more strict emission limits. For these reasons, in-cylinder pressure analysis must be carried out with maximum accuracy, in order to minimize the effects of its characteristic measurement errors. The exact determination of crank position when the piston is at top dead centre (TDC) is of vital importance, since a 1° degrees error can cause up to a 10% evaluation error on IMEP and 25% error on the heat released by the combustion: the position of the crank shaft (and hence the volume inside the cylinder) should be known with the precision of at least 0.1 crank angle degrees, which is not an easy task, even if the engine dimensions are well known: it corresponds to a piston movement in the order of one tenth of micron, which is very difficult to estimate. A good determination of the TDC position can be pursued by means of a dedicated capacitive TDC sensor, which allows a dynamic measurement (i.e. while engine is running) within the required 0.1° precision [1], [2]. Such a sensor has a substantial cost and its use is not really fast, since it must be fitted in the spark plug or injector hole of the cylinder. A different approach can be followed using a thermodynamic method, whose input is in-cylinder pressure sampled during the compression and expansion strokes: some of these methods, more or less valid, can be found in literature [3], [4], [5], [6], [7], [8]. This paper will discuss a new thermodynamic approach to the problem of the right determination of the TDC position. The base theory of the method proposed is presented in the first part, while the second part deals with the assessment of the method and its robustness to the most common in-cylinder pressure measurement errors.     

发动机颗粒排放全流稀释系统设计

在发动机颗粒排放测试过程中，排气稀释系统是必备的设备。目前排放测量法规所用的排气稀释系统有两种：一种是全流稀释系统，另一种是部分流稀释系统，主要设备依赖进口。本文设计了一种发动机排放测量全流稀释系统，可以满足车用发动机排放测量需要。     

车用直喷式柴油机微粒排放与排气烟度、碳氢化合物排放的关系

本文针对自然吸气式车用直喷柴油机６１１０的微粒排放与排气烟度、碳氢化合物的关系进行了试验研究。结果表明，柴油机的微粒排放可按简单的经验关系式根据排气烟度和碳氢化合物排放计算，算出的值和直接通过稀释排气并用滤纸采样法测得的值吻合较好。本算式可用于确定６１１０及类似柴油机按ＥＣＥＲ４９十三工况的微粒加权比排放量，而不必用复杂的微粒测量系统。     

乙醇/柴油不同掺醇途径的性能对比

为了对乙醇/柴油混合燃料的应用和研究获取更全面的认识,在增压柴油机上对比了燃用纯柴油时与泵掺法(高压油泵掺醇)、化醇法和蒸气法(进气道掺醇)对排放性能的影响.研究结果表明,泵掺法的当量燃油消耗率优于原机;化醇法和蒸气法在低、中负荷范围内的当量燃油消耗率增大,在中、大负荷范围内接近原机水平,泵掺法的HC排放较原机有一定的增加;CO排放在小负荷工况略有上升,大负荷时明显低于原机;NO_x排放有所下降,排气烟度显著降低,化醇法和蒸气法与原机比较,在所有工况的HC、CO排放均大幅上升;NO_x排放降低的幅度不大,排气烟度有一定的降低.高压油泵掺醇方式对增压柴油机性能的改善效果明显优于进气道掺醇方式。