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The Cooperative Lubrication Research (CLR) Oil Test Engine, usually called the L-38, has been used for nearly 25 years to evaluate copper-lead journal bearing protection of gasoline rnotoroils under high-temperature, heavy-duty conditions. The test is sensitive to aggressive surface active additives that may encourage bearing corrosion. The L-38 also provides an estimate of oil durability, assessing the resistance of an oil to the accumulation of acidic by-products of combustion that could attack copper-lead bearings. However, the L-38 engine dynamometer test uses a heavily leaded gasoline that is no longer representative of the commercial fuels available in North America, Europe, or Japan. Rather than discard the L-38, this paper describes work to modify the L-38 procedure to run with unleaded gasoline.

Increased awareness of preserving the environment has motivated the development of a wide variety of environmentally compatible products. Such products include environmentally compatible lubricants. Sale and use of these types of lubricants illustrates diligence by the lubricant manufacturer, original equipment manufacturer (OEM), and the consumer in contributing to a cleaner environment. The use of this type of lubricant could enhance the image of the lubricant manufacturer and vendor as well as the equipment manufacturer who employs such a fluid. To base such a lubricant on a vegetable oil creates a product environmentally friendly by its farming origin and its ability to readily biodegrade if released. No machinery is so uniquely suited to using vegetable oil based lubricants as agricultural equipment. Since this equipment is particularly close to the environment, the lubricant can easily come in contact with the soil, ground water, and crops.

One of the primary functions of modern heavy duty diesel (HDD) lubricants is to protect the engine against corrosion, which is typically accomplished by additives providing alkaline material, commonly represented as total base number (TBN). The majority of the TBN in HDD lubricants comes from ash-containing over-based detergents, with various metallic base and soap chemistries. In this publication, we discuss several overbased detergents and their efficacy in acid neutralization, as well as the resulting impact on corrosion protection. The performance differences are compared in a number of stationary API CJ-4 and CK-4 HDD engine screener tests. Furthermore, these results are confirmed with field trial data, including a comparison of CJ-4 oils with the upcoming API FA-4/CK-4 oils. The selection of overbased detergent type provides varying levels of acid neutralization and corrosion protection.

It has long been understood that the piston assembly of the internal combustion engine accounts for a significant proportion of total engine friction. Modern engines are required to have better fuel economy without sacrificing durability. The pursuit of better fuel economy drives trends like downsizing, turbocharging and direct injection fuelling systems that increase cylinder pressures and create a more arduous operating environment for the piston ring / cylinder bore tribocouple. The power-cylinder lubricant is therefore put under increased stress as modern engine technology continues to evolve. The conventional approach to investigating fundamental power-cylinder tribology employs bench-tests founded on assumptions which allow for simplification of experimental conditions.

The ASTM D6121 (L-37) is a key hypoid gear lubricant durability test for ASTM D7450-08 (API Category GL-5) and the higher performance level SAE J2360. It is defined as the ‘Standard Test Method for Evaluation of Load-Carrying Capacity of Lubricants Under Conditions of Low Speed and High Torque Used for Final Hypoid Drive Axles’. Pass/fail is determined upon completion of the test by rating the pinion and ring gears for several types of surface distress, including wear, rippling, ridging, pitting, spalling and scoring. Passing the L-37 in addition to the other tests required for API Category GL-5 credentials, as well as the more strenuous SAE J2360 certification, requires in-depth formulating knowledge to appropriately balance the additive chemistry. This paper describes the results of ASTM D6121 experiments run for the purposes of better understanding gear oil durability.

Low temperature pumpability is an important requirement for engine lubricants. It ensures that sufficient oil reaches the parts of the engine requiring wear protection on engine start-up. Until recently, most industry emphasis has been on the low temperature pumpability of the fresh oil. However, the oil can undergo a number of changes during its lifetime in the engine which adversely affect low temperature pumpability. Industry stakeholders are now expressing concerns about the potential risk of engine failures due to deterioration of low temperature pumpability of oils during their life cycle in the engine. Concerns have also been raised over the last few years that the move to Group III base stocks, while improving many of the properties of oil formulations, may also impact their retained low temperature pumpability.

Improving vehicle fuel economy is a major consideration for original equipment manufacturers (OEMs) and their technology suppliers worldwide as government legislation increasingly limits carbon dioxide emissions. At the same time that automotive OEMs have been driving toward lower viscosity axle oils to improve fuel economy, OEMs have worked to improved durability over an extended drain interval. These challenges have driven the use of API group III and/or API group IV base oils in most factory fill axle oils. This paper details the development of a novel lower viscosity SAE 75W-85 axle technology based on group II base oil that rivals the performance of a PAO-based axle oil and challenges the conventional wisdom of not using group II base oils in fuel efficient axle oils.

Market demand and evolving global legislation are forcing OEMs to improve fuel consumption and reduce CO2 emissions. Downsizing in direct injection gasoline engines has been a common strategy towards achieving this goal, but this requires increased boost pressures to maintain power. The increased boost pressures are creating a new abnormal combustion phenomenon known as Low-Speed Pre-Ignition (LSPI). Lubricants and fuels have been implicated as significant influencers of LSPI frequency and intensity. Part 1 of the series described the development of a statistical approach for measuring and quantifying LSPI activity. This statistical approach was shown to be consistent and repeatable. Part 2 of the series further refined the methodology from Part 1 to reduce the frequency of false positives and negatives. A baseline lubricant was used in both of these papers to demonstrate the robustness of this methodology.

In recent years, an abnormal combustion phenomenon called low-speed pre-ignition (LSPI) has arisen from the downsizing of gasoline engines in order to improve fuel economy and comply with global CO2 legislation. The type and quality of the fuel and lubricant has been found to influence LSPI occurrence rates. A methodology for studying LSPI has been implemented, and a rigorous statistical approach for studying the data from a stationary engine test can provide consistent results as shown in Part 1 of the series. LSPI events can be determined by an iterative statistical procedure based on calculating the mean and standard deviation of peak pressure (PP) and crank angle location of 2% mass fraction burned (MFB02) data, determining cycles with parameters which exceeded n standard deviations from the mean and identifying outliers. Outliers for the PP and MFB02 metrics are identified as possible LSPI events.

Deposit formation within turbocharger compressor housings can lead to compressor efficiency degradation. This loss of turbo efficiency may degrade fuel economy and increase CO2 and NOx emissions. To understand the role that engine oil composition and formulation play in deposit formation, five different lubricants were run in a fired engine test while monitoring turbocharger compressor efficiency over time. Base stock group, additive package, and viscosity modifier treat rate were varied in the lubricants tested. After each test was completed the turbocharger compressor cover and back plate deposits were characterized. A laboratory oil mist coking rig has also been constructed, which generated deposits having the same characteristics as those from the engine tests. By analyzing results from both lab and engine tests, correlations between deposit characteristics and their effect on compressor efficiency were observed.

In a two-stroke engine, carbon is a natural by-product of incomplete combustion. Fuel and oil quality vary leading to various degrees of carbon deposit build up on critical engine parts over time. If the carbon deposits are left on engine components and allowed to accumulate, it can lead to reduced horsepower, reduced fuel economy, increased emissions, and in the worst case the deposits can cause engine damage. A novel two-stroke engine oil was developed specifically to remove these deposits, restore the operating efficiency, and potentially lengthen the useful life of the two-stroke engine. In order to prove the restorative ability of this novel technology, dynamometer tests and field trials were conducted. In the dynamometer portion, the oil was tested in two of the standard TC-W3® certification tests for marine engine oils. The first was the OMC 40HP and the second was the OMC 70HP test.

Over several years, a fuel economy test measurement technique has been developed to highlight the magnitude of benefits expected in real world applications of different heavy-duty vehicle (HDV) engine oils in an operating vehicle. This method provides discriminatory results using an alternative to the widely used gravimetric fuel measurement methodology of Brake Specific Fuel Consumption (BSFC), in order to measure gains of <2% in a more repeatable manner. For the results to prove meaningful to the wider commercial audience, such as vehicle operators, original equipment manufacturers and oil providers, the systemic test vehicle operating conditions need to closely represent on-road conditions experienced on a daily basis by long haul, heavy duty diesel vehicles. This paper describes the parameters, necessary measures and methodologies required to record real world data and create representative proving ground test cycles.

In 1999 the ASTM Low Temperature Rheology of Used Engine Oils or LOTRUO task force was formed within Subcommittee D02.07 to address potential method and measurement issues for low temperature rheological determinations of used engine oils. A primary focus of this task force was to assist the heavy duty engine oil classification panel which was developing the new PC-9 category, to include a used oil pumpability specification from one of the new multicylinder EGR diesel engine tests. With anticipated soot loadings of 5-10% in some of these used oils, there was concern that standard ASTM test methods developed for fresh oil pumpability might not be suitable for these sooted oils. The task force conducted some preliminary work on a used Mack T8E test sample of approximately 5% soot loading. These data indicated that variation in preheating conditions could have significant influence on the low temperature properties measured by standard procedures.

An internal combustion engine operating on compressed natural gas (CNG) as fuel is usually under higher thermal stress compared to the same engine using gasoline fuel. This leads to various concerns on the operation of CNG engine and the performance of the lubricant, such increased wear, accelerated total base number depletion, and faster deterioration of the lubricant. Engine oil intended for compressed natural gas (CNG)-gasoline bi-fuel passenger car application must therefore be formulated to withstand the varied and often severe operating conditions, as well as maintain superior lubrication control and prolong engine life. PTT Public Company Limited (PTT) has developed a new CNG-gasoline lubricant meeting API SN/GF-5 performance category that is able to address the various operating concerns of bi-fuel passenger car engines, and at the same time provides extended oil drain interval (ODI) capability.

The laboratory tests used to define API GL5 have been the cornerstone of gear oil development for well over thirty years. In that time they have served the market very well. Lubricants developed with these test methods have provided adequate protection of axle components from severe wear, scuffing, corrosion, and oxidation. Recently, however, there has been an increasing trend toward extended drain intervals which changes the picture. Coupled with longer oil drain intervals there is a continuing increase of power throughput in the equipment. The combination of increased power and extended service life places significant stress on the oil such that the load carrying ability and thermal and oxidative stability could be greatly diminished under these conditions. During the past ten years the industry has been actively working toward a new gear oil specification that will address the performance needs of today's vehicles.

An oil consumption test procedure has been developed in a 6-cyl, 425 hp, turbocharged and after-cooled diesel engine. Tests conducted on reference oils agree with good and poor oil consumption characteristics found with these same oils in the field. This paper includes evaluations using the engine test procedure as well as various laboratory bench tests which measure the effects of viscosity, volatility, and oxidation stability. Both bench and engine test results indicate that traditional properties, such as viscosity and volatility, do not completely account for variations in oil consumption. The data indicate that the problam of obtaining low diesel engine oil consumption may involve a complex combination of factors.

THIS paper presents the results of a controlled field test of heavy-duty crankcase oils in a fleet of 15 Chevrolet cars. Operating conditions were selected to represent average or typical passenger-car service. After 15 months of operation (approximately 14,000 miles on each car) it was found that, in comparison with the results obtained with a nonadditive oil, a heavy-duty oil of MIL-0-2104 performance level reduced piston-ring wear by 37%, reduced cylinder-bore wear by 42%, and significantly improved engine cleanliness.

The specific goal of this project was to determine if there is a difference in the lube oil degradation rates in a heavy-duty diesel engine equipped with an EGR system, as compared to the same configuration of the engine, but minus the EGR system. A secondary goal was to develop FTIR analysis of used lube oil as a sensitive technique for rapid evaluation of the degradation properties of lubricants. The test engine selected for this work was a Caterpillar 3176 engine. Two engine configurations were used, a standard 1994 design and a 1994 configuration with EGR designed to meet the 2004 emissions standards. The most significant changes in the lubricant occurred during the first 50-100 hours of operation. The results clearly demonstrated that the use of EGR has a significant impact on the degradation of the engine lubricant.

This paper reviews the relative performance of prototype SAE 0W-20 and SAE 5W-20 ILSAC GF-4 [1, 2] mineral oils in severe taxi fleet service. Both oils contained the same additive technology, formulated to 0.05% mass Phosphorus. This level was targeted to gain field experience with oils formulated to meet proposed chemical limits for the ILSAC GF-4 specification [1, 2]. Though the limits in the final ILSAC GF-4 specification were increased to 0.08% mass Phosphorus, the 0.05% mass Phosphorus maximum is again proposed for the ILSAC GF-5 specification [3]. Used oil Chemical and Physical analysis was carried out at both interim and final drains (10,000 miles). Oil and fuel consumption were also monitored during the test. After a total mileage accumulation of 100,000 miles per vehicle, engine teardowns and physical ratings were performed on key engine components. It was concluded the performance of both lubricants was equivalent and acceptable.

The SAE Engine Oil Viscosity Classification (EOVC) Task Force has been gathering data in consideration of extending SAE J300 to include engine oils with high temperature, high shear rate (HTHS) viscosity below the current minimum of 2.6 mPa⋅s for the SAE 20 grade. The driving force for doing so is fuel economy, although it is widely recognized that hardware durability can suffer if HTHS viscosity is too low. Several Japanese OEMs have expressed interest in revising SAE J300 to allow official designation of an engine oil viscosity category with HTHS viscosity below 2.6 mPa⋅s to enable the development of ultra-low-friction engines in the future. This paper summarizes the work of the SAE EOVC Low Viscosity Grade Working Group comprising members from OEMs, oil companies, additive companies and instrument manufacturers to explore adoption of one or more new viscosity grades.