低黏度机油对发动机性能的影响

车用发动机通过使用低黏度的润滑油,可获得更大的动力性和经济性。以某1.5 L 4缸自然吸气发动机为例,研究采用较低黏度的SM-5W20代替原使用的SM 5W30对发动机性能的影响。采用Flowmaster软件建立发动机润滑系统模型,分析润滑油黏度对发动机润滑系统润滑油压力、流量和润滑油泵功耗的影响,分析表明,采用较低黏度的SM 5W20代替SM 5W30,润滑系统的流量增大了0.83%~6.72%,润滑油压力降低1.45%~5.98%,润滑油泵功耗降低了1.4%~6.58%。通过发动机台架试验,研究黏度对发动机摩擦功、功率、扭矩及油耗的影响,结果表明,使用SM-5W20比使用SM-5W30的发动机摩擦功低,在中低速下的燃油经济性提升。     

采用低黏度润滑油对发动机性能的影响

车用发动机通过使用低黏度的润滑油,可获得更大的动力性和经济性。以某1.5 L 4缸自然吸气发动机为例,研究采用较低黏度的SM 5W20代替原使用的SM 5W30对发动机性能的影响。采用Flowmaster软件建立发动机润滑系统模型,分析润滑油黏度对发动机润滑系统润滑油压力、流量和润滑油泵功耗的影响,分析表明,采用较低黏度的SM 5W20代替SM 5W30,润滑系统的流量增大了0.83%~6.72%,润滑油压力降低1.45%~5.98%,润滑油泵功耗降低了1.4%~6.58%。通过发动机台架试验,研究黏度对发动机摩擦功、功率、扭矩及油耗的影响,结果表明,使用SM 5W20比使用SM 5W30的发动机摩擦功低,在中低速下的燃油经济性提升。     

不同黏度等级润滑油的替代使用对发动机性能的影响

采用柴油发动机外特性、负荷特性、稳定性台架试验,研究SAE15W-40、SAEOW-30和SAE5W-30三种黏度等级的发动机油对柴油发动机动力性、经济性和稳定性的影响,考察不同黏度等级之间润滑油相互代用的可行性.结果表明:使用SAE15W-40级润滑油时,发动机具有较高的功率和扭矩,但油耗率高于使用SAEOW-30和5W-30级润滑油时;使用SAE15W-40润滑油时发动机具有最好的加速性能,使用SAEOW-30润滑油时次之,而使用SAESW-30润滑油时发动机的加速比较缓和;使用三种黏度等级润滑油时发动机工作条件稳定,表明在战时或紧急情况下,不同黏度等级的润滑油之间进行互相代用是可行的.     

低黏度机油对发动机/整车节能的影响

燃料经济性是现代汽车的发展趋势,优异的黏度指数改进剂和减摩剂可提高机油的燃料经济性。根据低黏度机油的特性,结合β-4G15发动机润滑系统特点,研究低黏度机油对发动机/整车节能的影响。以机油10W40作为基准油,通过发动机倒拖和万有特性试验考察了机油0W20、5W20和5W30对发动机减摩和节能的影响,并通过发动机800 h耐久试验考察了机油5W20对发动机耐久性的影响;以机油10W40作为基准油,通过整车NEDC试验考察了机油5W20和5W30对整车节能的影响。试验结果表明:采用低黏度机油可有效提高发动机/整车的燃料经济性。     

低黏度润滑油对涡轮增压发动机影响的试验研究

为了探究低黏度润滑油对涡轮增压发动机的影响,选用3种低黏度测试油0W20和参比油5W30进行台架试验,包括发动机机械损失试验和发动机万有特性试验。其中测试油0W20-1和0W20-2中添加了不同量的含钼摩擦改进剂,测试油0W20-3中添加了脂肪酸酯摩擦改进剂,且测试油0W20-1的黏度最低。选用黏度最低的测试油0W20-1进行发动机耐久试验。结果表明：在节气门全开和节气门全关2种工况下,含钼摩擦改进剂含量较高的测试油0W20-2摩擦力矩最小,相比参比油5W30分别可以降低发动机机械摩擦损失34.4%和19.3%;发动机的机械摩擦损失与摩擦改进剂的种类和添加量有关,相比脂肪酸酯摩擦改进剂,含钼摩擦改进剂更适应涡轮增压发动机工况,减少摩擦功的效果更好;低黏度润滑油能够提高车辆的燃油经济性,并且发动机关键摩擦副磨损量较小,满足发动机耐久性要求。     

润滑油改善汽车综合循环工况油耗的试验研究

已有台架试验研究表明润滑油对变速箱的传动效率有一定的影响,为此按照GB/T 12545.5-2008模拟汽车综合循环工况,采用整车台架模拟试验研究变速箱润滑油对汽车综合循环工况油耗的影响,验证了低黏度润滑油对提高变速箱以至于提升整车效率、降低整车油耗具有积极的作用。实验结果表明,不同黏度的变速箱润滑油对整车油耗有不同的影响,采用低黏度的变速箱润滑油能更有效地降低整车油耗。     

全合成机油黏度对增压发动机性能的影响

为了验证机油的黏度对发动机性能指标的影响,以国产某1.2 L排量增压发动机为例,使用较低黏度的美孚一号0W20 SN级代替原先使用的美孚一号5W30 SN级润滑油进行同一种状态的增压发动机性能对比台架试验。主要进行了净功率试验、机械损失试验、特征点油耗试验、万有特性试验等。结果发现:使用5W30机油的发动机动力性略优于使用0W20机油的发动机,经济性水平相当。因此,为发动机选用合适黏度的机油,能兼顾动力性和经济性。     

甲醇发动机机油特性研究

甲醇汽车发动机在台架试验过程容易出现如发动机冷启动困难、零部件磨损异常、橡胶件溶胀以及润滑油 乳化、结焦、油泥等问题。基于甲醇燃料的特性及对发动机润滑油的影响,采用发动机台架试验研究使用不同润滑油时 甲醇发动机的磨损和润滑油理化性质变化情况。研究结果表明,通过调整润滑油添加剂和润滑油黏度等级可以有效缓解 甲醇发动机的磨损、结焦等问题。     

甲醇发动机润滑油特性研究

甲醇汽车发动机在台架试验过程容易出现如发动机冷启动困难、零部件磨损异常、橡胶件溶胀以及润滑油乳化、结焦、油泥等问题。基于甲醇燃料的特性及对发动机润滑油的影响,采用发动机台架试验研究使用不同润滑油时甲醇发动机的磨损和润滑油理化性质变化情况。研究结果表明,通过调整润滑油添加剂和润滑油黏度等级可以有效缓解甲醇发动机的磨损、结焦等问题。     

润滑油对变速箱传动效率影响的试验研究

变速箱是汽车传动系统中重要组成之一,研究如何提高变速箱传动效率具有重要意义。润滑油影响变速箱使用性能,从而影响整车性能及油耗,其中润滑油的黏度是润滑油的重要理化指标之一。通过配制新的润滑油,分别研究试验油和参比油对变速箱传动效率台架试验及整车滑行油耗试验的影响情况。结果表明:黏度相对较低的润滑油对于提高变速箱传动效率及降低整车油耗有着重要意义,低粘化是变速箱油改善的方向之一。且在变速箱效率提1%时,综合油耗提升0.2L/100Km。     

Lubricating oil influence on exhaust hydrocarbon emissions from a gasoline fueled engine

Engine exhaust hydrocarbon emissions have been investigated for different lubricating oils, using gasoline as fuel. Six samples of lubricants have been tested: synthetic SAE 5W30 and SAE 5W40, semi-synthetic SAE 15W40 and SAE 20W50, and mineral SAE 15W40 and SAE 20W50. Experiments were carried out in a production engine mounted on a bench test dynamometer, varying engine load and speed in the range from 1500 to 6000 rev/min. The results demonstrate the influence of lubricant viscosity and base oil on hydrocarbon emissions. The synthetic oils showed the lowest hydrocarbon emission levels, especially in the low engine speed range.     

A new engine oil optimised for ecologically sensitive operational areas

In recent years, environmental awareness and legislation have focused public attention on vehicle emissions. Consequently, more research has been devoted to emissions and pollution by lubricants. A number of studies has been carried out to understand lubricant-related emissions and leak rates as well as the effects on fuel economy of using low viscosity grades of lubricant. The purpose of the present investigation was to develop for use in gasoline and diesel engines a crankcase lubricant which contained improved performance in engine cleanliness with fuel economy and a low rate of particle emissions. Emphasis was placed on low toxicology and rapid biodegradability because of the risk of unintentional emissions. Such a sophisticated lubricant is desirable not only for normal road vehicles but also and especially for use in ecologically sensitive areas. During the development of this lubricant, numerous laboratory tests were performed. In order to assess the quality and the fuel economy of the new lubricant, tests were carried out on an engine test rig and on a vehicle test bench. Field tests were run with various vehicles and stationary engines, using different fuel types. Unleaded gasoline, diesel fuels with a varying sulphur content, and rape seed oil methyl ester (RME) were used. This paper summarises the results of this investigation.     

The impact of detergent chemistry on TBN retention

Historically, the characterisation of fresh and used diesel engine lubricants has been based on a limited number of analytical techniques. One of the most important methods of analysis has been total base number (TBN) measurement. Although TBN measurements are informative, easy, and quick, it can be misleading to base the judgement of an oil's performance solely on one criterion. This paper offers some observations from a field test, showing that some detergent types gave unacceptable performance even though the TBNs were at an acceptable level. It is hypothesised that some detergents do not effectively neutralise all acidic species present in the lubricant, thereby reserving their own base, while in fact the oil may no longer provide sufficient protection against bearing corrosion. This hypothesis is supported by bench and engine test data. It is recommended that, at a minimum, total acid number (TAN) measurements be included in any analysis, and where time and cost permit, wear metals content, oxidation, soot content, and viscosity should also be evaluated.     

Temperature—friction characteristics of cylinder lubrication in large,slow, cross‐head marine diesel engines under boundary lubrication conditions

In large, slow, cross‐head marine diesel engines research has increasingly shown that the lubrication regime between piston rings and cylinder liner at top dead centre is of the boundary lubrication type due to the high gas pressure, low sliding speed, and high temperature. This means that the tribological properties of piston ring, cylinder liner, and cylinder lubricant in these types of engine under boundary lubrication conditions should be considered simultaneously when friction and wear between the piston ring and cylinder liner are studied. Until now there has been no standard method to evaluate boundary lubrication performance. There are a few traditional methods used in lubricant research, but their results are not correlated with service conditions. It is important to find a suitable method to evaluate the boundary lubrication performance of lubricants at the laboratory testing stage or before the engine testing stage. The important parameters, such as sliding speed, normal load, materials of the contacting pairs, and lubricant, need all to be controlled. In this paper a systematic experimental procedure, the ‘five times heating and cooling test’, is introduced to assess lubricant properties under boundary lubrication conditions. Most of the parameters mentioned above are controlled. The model contact, of pin‐on‐plate form, is made from the actual piston and liner materials used in a large‐bore, slow, cross‐head marine diesel engine. The temperature characteristics of different blends of lubricants are investigated under boundary lubrication conditions using a pin‐on‐plate reciprocating test rig. These blends of lubricants have the same additives but different base fluids; they nevertheless fulfil the physical and chemical requirements of a real marine diesel engine. The test temperature range is from room temperature to the working temperature of the top piston ring. The experiments show that there are different temperature—friction characteristics for lubricants with different bases and the same additive package and there are also different temperature—friction characteristics during heating up and cooling down for each blend. Single‐base lubricants have more promising temperature—friction characteristics than those of a blend of a high‐viscosity base and a low‐viscosity base at high temperature.     

柴油机油烟炱分散性能研究

通过模拟试验、发动机台架试验以及行车试验,考察柴油机润滑油的烟炱分散性能。结果表明:烟炱模拟试验能区分不同油品的烟炱分散能力;由于发动机技术的不同、试验目的的不同、试验条件设置的不同,台架试验结果会有很大差异,应根据发动机的技术特点,建立与润滑油在车辆实际使用过程中性能相关联的台架试验;质量级别越高的润滑油,其烟炱分散性能越好;不同分散性能、不同类型黏度指数改进剂的润滑油在行车试验中性能差异不大,特别是由烟炱引起的黏度变化基本没有表现出来,而黏度指数改进剂的剪切性能对黏度指标的影响比烟炱含量的影响表现得更为突出。     

Laboratory evaluation of the dispersancy power of a gasoline engine oil and its relationship with sequence VE test results

The evaluation of the dispersancy power of a gasoline engine oil is included among such international specifications as those of the Committee of Common Market Automobile Constructors (CCMC) and the American Petroleum Institute (API). Such an evaluation is carried out by means of long, severe, and expensive engine bench tests, the engines used being Mercedes M102E (CCMC G4 and G5 levels) or the Ford Pinto 2.3 (API SG and SH levels). The cost of these tests necessitates pre-selection of oils by laboratory tests and these need to be a reliable indicator of bench test performance. The present study proposes two new laboratory methods, the OXYDISP and the POTDISP tests, which associate artificial ageing of the lubricants with modified blotter spots tests. These tests showed excellent correlation with Sequence VE engine test results. They were also capable of distinguishing oils of different API standards. They therefore provide an effective tool for preselection of lubricants, without pretending to be a replacement of or substitute for Sequence VE or other engine bench tests.     

Lubricant viscosity and viscosity improver additive effects on diesel fuel economy

This work verifies the impact of lubricant viscosity and viscosity improver additives on diesel fuel economy. Eight lubricants were tested in a single-cylinder, four-stroke, direct injection diesel engine mounted on a dynamometer, under different load and speed conditions. Engine friction power was also investigated through Willans’ line. The results demonstrate that fuel economy obtained from multigrade viscosity oils is higher than that obtained from monograde viscosity oils. A linear relationship was obtained between the high temperature high shear viscosity and specific fuel consumption. The lubricant which provided lower fuel consumption also required lower friction power.     

基于神经网络-遗传算法优化柴油机油台架试验

根据15W/40 CD柴油机油的模拟实验与台架试验的基础数据,用人工神经网络(ANN)的反向传播算法建立了模拟实验与台架试验神经网络预测模型,该神经网络模型合适的拓扑结构为5-7-1,学习速率为0.2,动量因子为0.9。探讨了用模拟实验数据预测台架试验结果的可能性,检验证明用人工神经网络方法建立的模型能准确预报15W/40CD柴油机油的台架试验结果。该神经网络预测模型用遗传算法优化,得到了15W/40 CD级柴油机油能通过台架试验的最优模拟实验结果。     

工程机械混合动力系统实验台测控系统

为了研究工程机械混合动力系统的机电耦合特性和轴系的振动特性,研制了由柴油机、电动机和液压泵共轴连接组成的工程机械混合动力系统实验台.设计了由工控机、PCI总线控制卡和组态软件组成的实验台测控系统,分析测控系统输入信号和控制信号的数量与类型,确定测控系统控制策略的设计原则和开发过程.通过在柴油机输出轴的端面布置3个加速度传感器实现柴油机工作时曲轴的振动特性,对不同负载功率下柴油机曲轴的振动特性进行试验测试.测试结果表明,柴油机曲轴的振动能量集中在径向,轴向的振动能量可忽略不计;设计的测控系统能实现混合动力系统轴系振动性能测试.     

Polyalphaolefins — base fluids for modern heavy duty diesel oils

A combination of environmental legislation and a need for improved economics currently presents both OEMs and fleet owners with a conflicting set of performance and operational requirements. These include lower emission and paniculate levels, fuel economy, longer drain/service intervals, and enhanced engine durability. Improved engine lubricants will play a crucial role in achieving these goals. The impact of base-fluid composition and viscosity grade on emission/paniculate levels and fuel economy of a Euro II engine has been investigated. Polyalphaolefin-based lubricants appear as an encouraging solution, as shown by our results centred on an SAE 5W40 grade.