Search Results

The world is firmly focused on reducing energy consumption and on increasingly stringent regulations on CO2 emissions. Examples of regulatory changes include the new United States Environmental Protection Agency's (U.S. EPA) fuel economy test procedures which were required beginning with the 2008 model year for vehicles sold in the US market. These test procedures include testing at higher speeds, more aggressive acceleration and deceleration, and hot-weather and cold-temperature testing. These revised procedures are intended to provide an estimate that more accurately reflects what consumers will experience under real world driving conditions. The U.S.

Limited technical studies to speciate particulate matter (PM) emissions from gasoline fueled vehicles have indicated that the lubricating oil may play an important role. It is unclear, however, how this contribution changes with the condition of the lubricant over time. In this study, we hypothesize that the mileage accumulated on the lubricant will affect PM emissions, with a goal of identifying the point of lubricant mileage at which PM emissions are minimized or at least stabilized relative to fresh lubricant. This program tested two low-mileage Tier 2 gasoline vehicles at multiple lubricant mileage intervals ranging from zero to 5000 miles. The LA92 cycle was used for emissions testing. Non-oxygenated certification fuel and splash blended 10% and 20% ethanol blends were used as test fuels.

The operating conditions of a typical motorcycle are considerably different than those of a typical passenger car and thus require an oil capable of handling the unique demands. One primary difference, wet clutch lubrication, is already addressed by the current JASO four-stroke motorcycle engine oil specification (JASO T 903:2011). Another challenge for the oil is gear box lubrication, which may be addressed in part with the addition of a gear protection test in a future revision to the JASO specification. A third major difference between a motorcycle oil and passenger car oil is the more severe conditions an oil is subjected to within a motorcycle engine, due to higher temperatures, engine speeds and power densities. Scooters, utilizing a transmission not lubricated by the crankcase oil, also place higher demands on an engine oil, once again due to higher temperatures, engine speeds and power densities.

Increasingly stringent fuel economy and emissions regulations around the world have forced the further optimization of nearly all vehicle systems. Many technologies exist to improve fuel economy; however, only a smaller sub-set are commercially feasible due to the cost of implementation. One system that can provide a small but significant improvement in fuel economy is the lubrication system of an internal combustion engine. Benefits in fuel economy may be realized by the reduction of engine oil viscosity and the addition of friction modifying additives. In both cases, advanced engine oils allow for a reduction of engine friction. Because of differences in engine design and architecture, some engines respond more to changes in oil viscosity or friction modification than others. For example, an engine that is designed for an SAE 0W-16 oil may experience an increase in fuel economy if an SAE 0W-8 is used.

Requirements to improve vehicle fuel economy continue to increase, spurred on by agreements such as the Kyoto Protocol. Lubricants can play a role in aiding fuel economy, as evidenced by the rise in the number of engine oil specifications that require fuel economy improvements. Part of this improvement is due to achieving suitable viscometric properties in the lubricant, but additional improvements can be made using friction modifier (FM) compounds. The use of FMs in lubricants is not new, with traditional approaches being oleochemical-based derivatives such as glycerol mono-oleate and molybdenum-based compounds. However, to achieve even greater improvements, new new friction modifying compounds are needed to help deliver the full potential required from next generation lubricants. This work looks at the potential improvements available from new FM technology over and above the traditional FM compounds.

Phosphorus is known to reduce effectiveness of the three-way catalysts (TWC) commonly used by automotive OEMs. This phenomenon is referred to as catalyst deactivation. The process occurs as zinc dialkyldithiophosphate (ZDDP) decomposes in an engine creating many phosphorus species, which eventually interact with the active sites of exhaust catalysts. This phosphorous comes from both oil consumption and volatilization. Novel low-volatility ZDDP is designed in such a way that the amounts of volatile phosphorus species are significantly reduced while their antiwear and antioxidant performances are maintained. A recent field trial conducted in New York City taxi cabs provided two sets of “aged” catalysts that had been exposed to GF-4-type formulations. The trial compared fluids formulated with conventional and low-volatility ZDDPs. Results of field test examination were reported in an earlier paper (1).

With the increasing use of modern, EGR-equipped, heavy-duty diesel engines and the use of lower sulfur and alternate fuels, such as biodiesel, lubricants are being exposed to a range of different compositions of acids. To complement the traditional detergent bases, todays lubricants have evolved to include a higher proportion of basic materials from amine-derived sources to aid in oxidation and soot control. This paper explores the impact of the different sources of acids, some of the issues they create and how they can be addressed, exemplified in a prototype CJ-4 lubricant formulation.

Global original equipment manufacturers (OEMs) have requested lower viscosity automatic transmission fluid (ATF) for use in conventional and 6-speed automatic transmissions (AT) to meet growing demands for improved fuel economy. While lower-viscosity ATF may provide better fuel economy by reducing churning losses, other key performance attributes must be considered when formulating lower viscosity ATF(1,2). Gear and bearing performance can be key concerns with lower-viscosity ATFs due to reduced film thickness at the surfaces. Long-term anti-shudder performance is also needed to enable the aggressive use of controlled slip torque converter clutches that permit better fuel economy. And, friction characteristics need to be improved for higher clutch holding capacity and good clutch engagement performance. This paper covers the development of next-generation, low-viscosity ATF technology, which provides optimum fuel economy along with wear and friction durability.

One of the key functions of lubricating oil additives in diesel engines is to control oil thickening caused by soot accumulation. Over the last several years, it has become apparent that the composition of the base oil used within the lubricant plays an extremely important role in the oil thickening phenomenon. In particular, oil thickening observed in the Mack T-8 test is significantly affected by the aromatic content of the base oil. We have found that the Mack T-8 thickening phenomenon is associated with high electrical activity, i.e., engine drain oils which exhibit high levels of viscosity increase show significantly higher conductivities. These findings suggest that electrical interactions are involved in soot-induced oil thickening.

Life Cycle Assessment (LCA) is a methodology used to determine quantitatively the environmental impacts of a range of options. The environmental community has used LCA to study all of the impacts of a product over its life cycle. This analysis can help to prevent instances where a greater degree of environmental harm results when changes are made to products based on consideration of impacts in only part of the life cycle. This study applies the methodology to engine lubricants, and in particular chlorine limits in engine lubricant specifications. Concern that chlorine in lubricants might contribute to emissions from vehicle exhausts of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), collectively called PCDD/F, led to the introduction of chlorine limits in lubricant specifications. No direct evidence was available linking chlorine in lubricants to PCDD/F formation, but precautionary principles were used to set lubricant chlorine limits.

Recently, research and testing of oxygenated diesel fuels has increased, particularly in the area of exhaust emissions. Included among the oxygenated diesel fuels are blends of diesel fuel with ethanol, or E diesel fuels. Exhaust emissions testing of E diesel fuel has been conducted by a variety of test laboratories under various conditions of engine type and operating conditions. This work reviews the existing public data from previous exhaust emissions testing on E diesel fuel and includes new testing performed in engines of varied design. Emissions data compares E diesel fuel with normal diesel fuel under conditions of different engine speeds, different engine loads and different engine designs. Variations in performance under these various conditions are observed and discussed with some potential explanations suggested.

The regulatory drive for emission reductions, increased fuel costs, and likely increases in Corporate Average Fuel Economy (CAFE) requirements have made fuel efficiency a key issue for North American vehicle manufacturers and marketers. At the same time the popularity of sport utility vehicles and light trucks has made it more difficult to achieve CAFE objectives. In order to accommodate both public vehicle preference and government mandated CAFE requirements automobile manufacturers are seeking all available means to increase fuel economy through advanced system design, engineered materials, and improved lubricant technology. Axle lubricants can have a significant impact on fuel economy; moreover, axle lubricants can be tailored to deliver maximum operating efficiency over either specific or wide ranges of operating conditions.

A new gas phase kinetic model using Westbrook's gas phase n-heptane model and Frenklach's soot model was constructed. This model was then used to predict the impact on PAH formation as an indices of soot formation on ethanol/diesel fuel blends. The results were then compared to soot levels measured by various researchers. The ignition delay characteristics of ethanol were validated against experimental results in the literature. In this paper the results of the model and the comparison with experimental results will be discussed along with implications on the method of incorporation of additives and alternative fuels.

The Association des Constructeurs Européen d'Automobiles (ACEA) light duty diesel engine specifications requires a kinematic viscosity measurement technique for Peugeot XUD-11 BTE drain oils. This viscosity measurement is used to define the medium temperature dispersivity of soot in the drain oil.(1) This paper discusses the use of rotational rheology methods to measure the Newtonian character of XUD-11 drain oils. The calculation of the rate index using the Hershel Bulkley model indicates the level of non-Newtonian behavior of the drain oil and directly reflects the level of soot dispersion or agglomeration. This study shows that the more non-Newtonian the drain oil the greater the difference between kinematic and rotational viscosity measurements Oscillation (dynamic) rheological techniques are used to characterize build up of soot structure.

Modern high power density gasoline fueled engines place an ever-increasing demand on the engine lubricant. In this study, it is shown that advances in engine design to increase performance, improve fuel economy and lower emissions have outpaced the development of typical commercial engine lubricants. Advanced designed engines began to experience oil starvation as a result of a combination of driving cycles, oil quality and poor maintenance practices. The cause was traced to excessive increases in borderline pumping viscosity as measured by MRV TP-1 (ASTM D4684). Used oil analysis for MRV TP-1 showed viscosity greatly increased in excess of stay-in-grade requirements and in many cases the crankcase lubricant was solid at the temperature appropriate for its viscosity grade. However, at the same time CCS values were in grade or only slightly (1W grade) elevated.

Light trucks and sport utility vehicles (SUVs) have become extremely popular in the United States in recent years, but this shift to larger passenger vehicles has placed new demands upon the gear lubricant. The key challenge facing vehicle manufacturers in North America is meeting government-mandated fuel economy requirements while maintaining durability. Gear oils must provide long-term durability and operating temperature control in order to increase equipment life under severe conditions while maintaining fuel efficiency. This paper describes the development of a full-scale light duty axle test that simulates a variety of different driving conditions that can be used to measure temperature reduction properties of gear oil formulations. The work presented here outlines a test methodology that allows gear oil formulations to be compared with each other while accounting for axle changes due to wear and conditioning during testing.

Light trucks and sport utility vehicles (SUVs) have become extremely popular in the United States in recent years, but this shift to larger passenger vehicles has placed new demands upon the gear lubricant. The key challenge facing vehicle manufacturers in North America is meeting government-mandated fuel economy requirements while maintaining the durability required for severe service. In light truck/SUV applications, gear oils must provide operating temperature control under extreme conditions such as trailer-towing. Higher operating temperatures for prolonged periods can adversely affect metallurgical properties and reduce fluid film thickness, both of which can lead to premature equipment failures. In our view, operating temperature is an important indicator of durability. Unfortunately, lubricants optimized for temperature control do not always provide the best fuel economy.

The primary goal of the USAF JP-8+100 thermal stability additive (TSA) program is to increase the heat-sink capacity of JP-8 fuel by 50%. Current engine design is limited by a fuel nozzle temperature of 325°F (163°C); JP-8+100 has been designed to allow a 100°F increase in nozzle temperatures up to 425°F (218°C) without serious fuel degradation leading to excessive deposition. Previous studies have shown that TSA formulations increase the electrical conductivity of base jet fuel. In the present paper, further characterization of this phenomenon is described, as well as interactions of newer TSAs with combinations of SDA and other surface-active species in hydrocarbons, will be discussed.

The search for alternative energy sources, particularly renewable sources, has led to increased activity in the area of ethanol blended diesel fuel, or E diesel. E diesel offers potential benefits in reducing greenhouse gases, reducing dependence on crude oil and reducing engine out emissions of particulate matter. However, there are some concerns about the use of E diesel in the existing vehicle fleet. One of the chief concerns of the use of E diesel is the affect of the ethanol on the lubricating properties of the fuel and the potential for fuel system wear. Additive packages that are used to formulate E diesel fuels can improve fuel lubricity and prevent abnormal fuel system wear. This work studies the lubricity properties of several E diesel blends and the diesel fuels that are used to form them. In addition to a variety of bench scale lubricity tests, injector pump tests were performed as an indicator of long term durability in the field.

The effects of lubricating oil on friction and engine-out emissions in a light-duty 2.2L compression ignition direct injection (CIDI) engine were investigated. A matrix of test oils varying in viscosity (SAE 5W-20 to 10W-40), friction modifier (FM) level and chemistry (MoDTC and organic FM), and basestock chemistry (mineral and synthetic) was investigated. Tests were run in an engine dynamometer according to a simulated, steady state FTP-75 procedure. Low viscosity oils and high levels of organic FM showed benefits in terms of fuel economy, but there were no significant effects observed with the oils with low MoDTC concentration on engine friction run in this program. No significant oil effects were observed on the gaseous emissions of the engine. PM emissions were analyzed for organic solubles and insolubles. The organic soluble fraction was further analyzed for the oil and fuel soluble portions.