齿轮滑油对轿车齿轮传动效率和燃油经济性的影响

1．首先应当考虑轿车的油耗只和摩擦学有关,其中影响最明显的是润滑油。2．采用测量润滑方法只能阐述机械损失,因此,燃油经济性实现改善的可能性受到了限制,特别当考虑齿轮高效率的时候,3．在评价粘性对燃油消耗的影响时,所谓粘性必须考虑有效粘性,对这非牛顿油是非常重要的,4．按SAE粘度梯度降低齿轮油粘度,将可使燃油消耗在高温时降低0．2－1．5％,低温时降低0．4－2．5％。5．在齿轮油中应用摩擦改良时,燃油消耗的实际降低在1．0－6．0％之间。6．减少摩阻50％的基础上,考虑不同的传动过程,燃油消耗降低为其他齿轮油1．0－5．1％之间。7．汽车齿轮试验,使燃油消耗改善大小顺序按为其他齿轮油1％。8．测量结果确定计算估价的原则。     

Demonstrating Improved Fuel Economy Using Subsystem Specific Lubricants on a Modified Diesel Engine

Fuel economy performance in modern internal combustion engines is of increasing importance to lubricant formulators due to regulations targeting global greenhouse gas emissions. Engines typically employ a single lubricant, with a common sump, to service all components. As a result, base oil and additive selection for fuel economy performance is a compromise among competing demands for different engine subsystems. Opportunities for significant fuel economy improvement through targeted formulation of lubricants for specific engine subsystems are presented, with specific emphasis on segregating the lubricant supplies for the valve train and the power cylinder subsystems. A working prototype was developed in a lab environment by modifying a commercially available twin-cylinder diesel engine. Motored valve train and whole-engine fired test results were obtained and compared to model data. Fuel economy benefits were demonstrated using market representative heavy-duty diesel lubricants, including mineral oil and polyalphaolefin (PAO) blends. The fuel economy benefits of a dual-loop lubricant system are demonstrated through significant viscosity reduction in the power cylinder subsystem, achieving overall engine friction reductions of up to 8% for the investigated operating condition. Results suggest that additional gains may be realized through targeted base oil and additive formulation. Implications for incorporation in larger diesel engines are also considered.     

汽车的节能要求与润滑剂技术的发展

介绍了发动机油节能试验的发展和润滑剂流变性质、润滑油摩擦改进剂等对燃油经济性的影响和作用机理。指出了发动机油的流变性能是影响油品节能效果的重要因素,具有合理高温高剪切粘度的高粘度指数、低粘度和低粘压系数的发动机油利于节能;通过吸附作用而起到减摩效果的有机摩擦改进剂在中等温度条件下具有明显的减摩作用,利于改善发动机油的节能效果;深度精制的高粘度指数基础油的使用可以提高发动机油节能效果和保持能力。     

Pretreatment methods to improve the kinematic viscosity of biodiesel for use in power tiller engines

Biodiesel is an environmentally friendly fuel that can replace diesel in compression ignition engines without changing the engine structure. Biodiesel is typically manufactured from vegetable oils and animal fats, which give the fuel its oxidation stability and cold-flow properties, respectively. However, the kinematic viscosity of biodiesel can cause engine performance problems such as incomplete combustion and sludge formation due to insufficient fuel atomization. To address these problems, in this study, a pretreatment technology that lowers the kinematic viscosity of biodiesel made from blended animal fat and vegetable oil was developed. The results of application of the pretreated fuel to a single-cylinder power tiller engine indicated that it produced 88.3–99.8 % of the brake power produced by conventional diesel. In addition, although the pretreated biodiesel exhaust included increased amounts of nitrogen oxides and carbon dioxide emissions, the proposed fuel also decreased the amounts of hydrocarbon and carbon monoxide emissions compared with conventional diesel emissions.

     

The influence of engine oil on diesel exhaust emissions

Increasingly stringent emission legislation, together with the requirements for improved diesel engine performance, such as fuel economy, friction reduction, and extended drain intervals, have led to attention being focused on engine oil quality. The use of low‐friction engine oils can improve engine fuel efficiency and lead to a significant reduction of gaseous emissions. Therefore, engine oil is of importance when considering engine design parameters. This paper describes a study of the contribution of engine oil to diesel exhaust emissions. The investigations have shown that diesel engine particulate emissions as well as hydrocarbons and NO_X emissions depend on the lubricant oil properties, in particular on the sulphur content, volatility, and metal content.     

以汽油和甲醇为燃料时小型二冲程发动机摩擦特性比较

采用往复振动机模拟小型二冲程发动机运转工况，实验研究汽油和甲醇为燃料时发动机气缸和活塞环间的摩擦特性，并比较分别使用润滑油新油、润滑油老化油、润滑油新油和老化油的混合油作为润滑油时气缸和活塞环间的摩擦特性。结果表明，以甲醇为燃料时的摩擦因数和磨损量均小于以汽油为燃料时的摩擦因数和磨损量，特别是使用添加了润滑油新油的燃料时的摩擦因数和磨损量最小。通过黏度和热重（TG）分析，探讨甲醇燃料改善气缸和活塞环间的摩擦特性的原因，结果表明，甲醇燃料具有较高的黏度和较低的摩擦因数，因而以甲醇为燃料时可以降低磨损     

Friction modifiers in engine and gear oils

Reducing friction is an important target for any lubricant oil formulator. There are several ways, such as utilisation of multi‐grade oils with low viscosity at low temperature, or use of friction modifiers, to reduce friction in automotive engines and transmissions and thus save fuel. A good means to obtain an energy‐saving lubricant is by the addition of a friction‐reducing additive in a high‐range multigrade oil. This paper presents some considerations on the action mechanism of friction modifiers and the results obtained in engine and gear oils with two new nitrogen‐, sulphur‐, and boron‐containing additives.     

Literature review of OCP viscosity modifiers

Olefin copolymers and terpolymers (OCPs) are used as viscosity modifiers in a large proportion of the European and world multigrade oil market. The polymer properties of the basic ethylene propylene polymers are critical to the physical characteristics of the final lubricant and its engine performance. The important parameters are discussed. Ethylene propylene polymers intended for use in other industrial applications should be checked thoroughly to avoid potential field problems. Modifications of these speciality OCPs to dispersant polymers enhance diesel and dispersant lubricant properties, enabling the most severe lubricant performance requirements to be met. The paper also reviews developments reported in the literature on the production and handling of the products together with their application, particularly with reference to their effect on low temperature properties, engine cleanliness, wear and fuel economy of the lubricant.     

Performance and emission studies on an agriculture engine on neat Jatropha oil

Diesel engines have proven their utility in the transportation, agriculture, and power sectors in India. They are also potential sources of decentralized energy generation for rural electrification. Concerns on the long-term availability of petroleum diesel and the stringent environmental norms have mandated the search for a renewable alternative to diesel fuel to address these problems. Vegetable oils have been considered good alternatives to diesel in the past couple of years. However, there are many issues related to the use of vegetable oils in diesel engine. Jatropha curcas has been promoted in India as a sustainable substitute to diesel fuel. This study aims to develop a dual fuel engine test rig for evaluating the potential suitability of Jatropha oil as diesel fuel and for determining the performance and emission characteristics of an engine with Jatropha oil. The experimental results suggest that engine performance using Jatropha oil is slightly inferior to that of diesel fuel. The thermal efficiency of the engine was lower, while the brake-specific fuel consumption was higher with Jatropha oil compared with diesel fuel. The levels of nitrogen oxides (NOx) from Jatropha oil during the entire duration of the experiment were lower than those of diesel fuel. The reduction of NOx was found to be an important characteristic of Jatropha oil as NOx emission is the most harmful gaseous emission from engines; as such, its reduction is always the goal of engine researchers and makers. During the entire experiment, carbon monoxide (CO), hydrocarbon (HC), and carbon dioxide (CO₂) emissions in the case of using Jatropha oil were higher than when diesel fuel was used. The higher density and viscosity of Jatropha oil causes lower thermal efficiency and higher brakespecific fuel consumption. The performance and emission characteristics found in this study are significant for the study of replacing diesel fuel from fossils with Jatropha oil in rural India, where the availability of diesel has always been a problem.     

涡轮增压发动机用0W-20润滑油减摩性能研究

为研究低黏度润滑油对涡轮增压发动机燃油经济性的影响,配制5种不同的0W-20全配方润滑油。使用真实活塞环-缸套摩擦副试样,选取涡轮增压发动机关键工况,通过往复摩擦模拟试验测试各油样的减摩效果。通过控制整车WLTC油耗测试精度,比较各油样的燃油经济性提升效果。结果表明：降低润滑油黏度和添加摩擦改进剂均可以改善燃油经济性,但是后者的效果更为显著;摩擦改进剂MoDTC的加剂量越高,减摩效果越好;硼酸盐清净剂可以增强MoDTC的减摩效果。比较摩擦模拟试验和整车油耗试验发现,使用真实的环套摩擦副组件并设定合适工况的摩擦模拟试验,可以快速区分润滑油的减摩效果,但是无法反映真实的燃油经济性的提升程度。     

Effect of mechanical shear on the thin‐film properties of base oil‐polymer mixtures

The thickness and frictional characteristics of thin lubricant films are known to affect the fuel economy properties of oils. The base oil and polymer compositions of the lubricant are generally considered to be critical chemical factors that can influence these thin‐film lubricant properties in new oils. However, it is important to produce lubricants with good fuel economy properties that are maintained after the lubricant is degraded. Lubricants in use can undergo oxidation and mechanical shear degradation. The effect of oxidation degradation on thin‐film physical properties has previously been studied. This paper investigates the effect of mechanical shearing on thin‐film properties. Dispersant olefin copolymers are found to reduce thin‐film friction in simple mixtures and in fully formulated oils. In simple mixtures, shearing the dispersant olefin copolymers does not affect the friction‐reducing ability of these polymers. In fully formulated oils, even though shearing diminishes to a degree the friction‐reducing ability of dispersant olefin copolymers, these copolymers can still provide significant friction reduction.     

The Effect of Lubricant Viscosity and Composition on Engine Friction and Bearing Wear

This paper investigates the effect of lubricant composition on engine friction and connecting-rod bearing wear. Special attention has been given to polymer-thickened (VI improved) oils since these oils are characterized by shear-dependent viscosity and a simultaneous occurrence of viscous and elastic properties. The variables investigated in this study included lubricant viscosity, polymer type, and concentration.

Two sets of engine studies were conducted, one to determine engine friction, the other to measure connecting-rod bearing wear, using irradiated bearings. For Newtonian fluids, the engine friction and wear response can be predicted from classical lubrication theory—that is, (a) friction decreases with increaing viscosity until a viscosity is reached where friction is a minimum; beyond this viscosity, further increases in viscosity result in increased friction. (b) Bearing wear decreases with increasing viscosity, but as a step function, not linearly, and the transition viscosity (of the step) corresponds to the viscosity which gives a minimum engine friction.

The addition of polymeric VI improvers (non-Newtonian fluids) to mineral oil base stocks reduces engine friction and lowers bearing wear—the amount of friction and wear reduction depending on the polymer type and concentration. This paper demonstrates that polymer-thickened oils actually give better bearing wear performance than their comparable mineral oil counterparts despite the fact that they have a lower apparent viscosity at high rates of shear. In addition, it appears that temporary viscosity loss is not the sale cause of the reduced engine friction of polymer-thickened oils.     

Comparison of the Effects of Biodiesel and Mineral Diesel Fuel Dilution on Aged Engine Oil Properties

Dilution of engine oil occurs when fuel is injected late in the combustion cycle to regenerate the diesel particulate filter used for trapping particulate emissions. Fuel dilution reduces oil viscosity and the concentration of engine oil additives, potentially compromising lubricant performance. Biodiesel usage may compound these issues due to its oxidative instability, and its higher boiling point compared to mineral diesel potentially causes it to concentrate more in the oil sump.

In this work, different amounts of mineral diesel and biodiesel (soy methyl ester, SME) were combined with 15W-40 CJ-4 diesel engine oil in laboratory oil aging experiments. Fuel was added and oil samples were withdrawn at periodic intervals. The oils were analyzed using typical oil analysis procedures to determine their condition, and wear evaluations under boundary lubricating conditions were determined using a high-frequency reciprocating rig (HFRR). Results showed that fuel dilution accelerated engine oil degradation, with biodiesel having a larger effect. However, friction remained unchanged with dilution, and wear actually decreased for fuel-diluted oils after 48 h of aging compared to aging without fuel dilution. Examination of the tribofilms by ultraviolet (UV) and visible Raman spectroscopy as well as Auger electron spectroscopy showed that additional carbon-containing components were present on tribofilms formed from fuel-diluted oils. These fuel-derived components may be responsible for the decreased wear observed.     

A new test technique for the laboratory evaluation of energy-efficient engine oils

Testing lubricants for fuel economy is a significant part of the drive for energy conservation. Generally, the small differences in fuel economy between lubricants make measurements inherently uncertain. Furthermore, precise engine tests for assessment of energy efficiency are expensive and time consuming. There has been a need, therefore, for the development of an effective laboratory screening technique to assess the energy efficiency of engine oils. With this objective in view, a new test technique consisting of two different tests has been developed for measuring lubricant-related fuel economy. Fuel economy through the use of engine oil is achieved by reducing boundary friction and viscous friction. Whereas reduction in boundary friction is obtained through the use of friction modifiers in engine oil, viscous friction is reduced through the use of low viscosity oils and by multigrading. The efficacy of action of friction modifiers in reducing boundary friction has been assessed with a SRV-Oscillating Friction and Wear Tester, using point and piston ring/liner segment contact. For the measurement of viscous friction, an attempt has been made to find out the reduction in viscous friction by using low viscosity oils and multigrade oils on a SAE No. 2 Machine, with all-steel clutch plates.     

抗磨添加剂对不同服役阶段润滑油摩擦学性能的影响

采用黏度测试仪测定新油及3种不同服役阶段润滑油的黏度,采用UMT-II摩擦磨损试验机考察其摩擦学性能,并同时考察3种在用润滑油添加抗磨添加剂后的摩擦学性能。研究结果表明:润滑油的黏度随着运行里程数的增加呈现先降后增的趋势;随润滑油运行里程数的增加,润滑油的摩擦因数增大,导致试验钢球的磨损量也增加;抗磨添加剂对不同服役阶段的润滑油的抗磨性能影响程度不同,在磨合磨损期和正常磨损期,加入抗磨添加剂后并不能改善润滑油的抗磨性能,而在异常磨损期,抗磨添加剂的加入可较好地改善润滑油的抗磨性能。     

Advanced low viscosity synthetic passenger vehicle engine oils

Premium quality synthetic passenger vehicle engine oils have been marketed by the authors' company since the early 1970s. During this time, the performance benefits of synthetic-based engine oils have been documented in a wide variety of engine and vehicle tests. The purpose of this paper is to demonstrate that, with the use of synthetic base oils and advanced additive technology, low viscosity oils can be formulated that have high fuel efficiency but which retain superior engine protection and performance reserves. Specifically, two synthetic engine oils, an SAE OW–40 and an SAE OW–30, have been developed that exceed the highest industry standards in both US (AP1)and European (ACEA) fuel economy and durability engine tests. The high quality of this technology is demonstrated in industry-standard engine and laboratory performance tests, as well as non-standard tests, such as extended-length engine tests, vehicle fuel economy tests, high mileage chassis rolls tests, and extended oil drain ‘over-the-road’ vehicle tests.     

新型减摩润滑剂改善汽油/柴油发动机动力性能的研究

利用合成和复配技术制备了新型减摩润滑剂，采用WD615型柴油发动机和C698QA型汽油发动机进行了全速全负荷的加速强化台架试验和300摩托小时的可靠性台架试验，考察了该润滑剂作为CD15W／40和SF10W／30机油添加剂对发动机功率、扭矩、机械损失、油耗等外特性的影响。结果表明：研制的减摩润滑剂在改善车辆发动机的动力性能和延长使用寿命方面具有良好的效果．与CD15W／40机油相比，该润滑剂能够使柴油发动机的功率、扭矩分别提高2．1％、2．0％．降低机械损失4％，节省油耗达1．8％；与SF10W／30机油相比，使用新型减摩润滑剂后的汽油发动机最人功率和最大扭矩分别升高了6．1％和2．0％，油耗降低了6．0％。这是由于该润滑剂充分利用了配方中多种功能添加剂的单剂特性和复合协同功效，提升了传统润滑油的减摩润滑性能和整体性能。     

Viscosity and working efficiency analysis of soybean oil based bio-lubricants

This article presents significant data about viscosity and working efficiency analysis for developing the soybean oil based bio-lubricants. A suitable viscosity or viscosity index (VI) plays a very important role in a lubricant, which can avoid collision and rubbing between components of mechanical devices in work as well as optimize working efficiency of a machine. In general, low friction between devices can increase working efficiency of a machine, but low viscosity of a lubricant will easily cause collision and rubbing between components of mechanical devices in work. A too viscous lubricant also requires a large amount of energy to move, but a too thin lubricant will easily cause rubbed devices and increased friction. To replace the mineral oils and syntholubes, the soybean oil is recently become one of the most actively studied oils due to its eco-friendly organic property and lower cost. This work used mixtures of the original soybean oil, the epoxidized soybean oil, and the hydrogenated soybean oil as the base oils. Applications are focused on developing engine bio-lubricants. The results show that the epoxidized soybean oil has extremely large viscosity in comparison with the engine lubricants as well as the original soybean oil, whereas the hydrogenated soybean oil is clearly opposite. This viscosity analysis offers good informations to fit viscosity of the engine lubricants by mixing the three soybean oils as base oils.     

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.     

Oil Degradation in a Diesel Engine with Dual-Loop Lubricating System

A common lubricating oil sump is used in most modern internal combustion engines for cooling, wear protection, and friction reduction. This requires compromises during base oil and additive selection as a result of differing needs for lubricant performance in engine subsystems. The use of a dual lubricating loop, providing separate oil sumps for the power cylinder and valve train subsystems, was investigated experimentally to determine the effect of system segregation on oil degradation. A small diesel engine was modified, installed in a commercial generator unit, and operated for one oil drain cycle. Oil sampling was tailored to assess base and acid numbers, oxidation, soot concentration, water content, and viscosity changes. The experiment complemented an earlier study that investigated the fuel economy benefits of such a lubricating configuration. These include longer drain intervals for the cylinder head and power cylinder subsystems, improved wear performance for the valve train, and opportunities for alternative material selection during engine design. The experiment demonstrated protection of the valve train subsystem from soot contaminants in the power cylinder. Lower total acid number and oxidation tendency was also observed in the valve train.