Search Results

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.

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.

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.

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.

Global environmental and economic concerns of today's world dictate strict requirements for modern heavy duty engines, especially in emissions, noise control, power generation, and extended oil drain intervals. These requirements lead to increased stresses imposed on lubricants in modern heavy duty engines. At the same time, the original equipment manufacturers (OEMs) desire additional fuel economy from the lubricating oil, requiring the use of lower viscosity lubricants to minimize frictional losses in the engine. These lower viscosity oils are subjected to increased stresses in the engine and need to provide robust performance throughout their lifetime in order to protect engine parts from wear and damage. One of the most important lubricant qualities is to maintain viscosity throughout the drain interval and thus provide continuous engine protection.

This paper outlines the second part in a series on the effect of polymeric additives commonly known as viscosity modifiers (VM) or viscosity index improvers (VII) on gear oil efficiency and durability. The main role of the VM is to improve cold temperature lubrication and reduce the rate of viscosity reduction as the gear oil warms to operating temperature. However, in addition to improved operating efficiency across a broad temperature range compared to monograde fluids the VM can impart a number of other significant rheological improvements to the fluid [1]. This paper expands on the first paper in the series [2], covering further aspects in fluid efficiency, the effect of VM chemistry on these and their relationship to differences in hypoid and spur gear rig efficiency testing. Numerous VM chemistry types are available and the VM chemistry and shear stability is key to fluid efficiency and durability.

Diesel engine oils containing a balanced additive package composed of oxidation, corrosion, wear, rust and foam inhibitors plus ashless dispersants and metallic detergents provide long engine life. The major factor is metallic detergent component which contributes alkalinity to the oil and has a direct effect on engine cleanliness and durability. Increased detergent alkalinity reduces deposits and wear, resulting in improved oil control and longer engine life. Careful selection of detergent components is required to control cylinder-bore polishing in diesel engines to assure optimum antiwear and oil control performance.

The most important property of the engine oil is its ability to reach all engine parts. Once there, it can build an oil film which protects these parts from wear and ultimately from destruction. No other lubricant property is relevant if the oil cannot be delivered to the critical engine parts. Thus engine oil pumpability, especially pumpability at low temperatures when the viscosity of the lubricant is the highest, is crucially important. The crankcase lubricant industry has recognized this, in requiring good low temperature pumpability for the last three decades. While good low temperature properties of the fresh oils are a necessary requirement for a lubricant, they are not sufficient to ensure the lifetime performance of the oil in the engine. The oil gradually ages in the engine and its properties, including low temperature pumpability, change.

A new field test procedure for evaluation of the sludge formation tendencies of lubricants has been developed. The procedure has the benefits of short running time, reduced variability, and dramatic separation of API SF vs API SG oils. This paper discusses development of the operational procedure and evaluation of four lubricants, including commercial-type API SF and API SG oils as well as experimental future oils. Significantly improved sludge ratings were obtained with an experimental API SG oil. The sludge formation process was studied using infrared spectroscopy, TAN, dielectric measurements, viscosity, quasielastic light scattering particle size, and transmission electron microscopy techniques. These analyses show production of contaminants which form insoluble particles that build up and precipitate out of suspension as sludge. Certain drain analyses can be used as tools for predicting field sludge deposition time.

The automotive vehicle market has seen an increase in the number of hybrid electric vehicles (HEVs), and forecasts predict additional growth. In HEVs, the hybrid drivetrain hardware can combine electric motor, clutches, gearbox, electro-hydraulics and the control unit. In HEV hardware the transmission fluid can be designed to be in contact with an integrated electric motor. One transmission type well-suited to such hybridization is the increasingly utilized dual clutch transmission (DCT), where a lubricating fluid is in contact with the complete motor assembly as well as the DCT driveline architecture. This includes its electrical components and therefore raises questions around the suitability of standard transmission fluids in such an application. This in turn drives the need for further understanding of fluid electrical properties in addition to the more usually studied engineering hardware electrical properties.

Increasing vehicle efficiency has been one of the key drivers of the automotive industry worldwide due to new government emission legislations and rising fuel costs. While original equipment manufacturers (OEMs) are responding with innovative hardware designs for new models, lubricant companies are developing additive solutions to reduce frictional losses in the engine thereby increasing fuel economy of both new and existing vehicles. Fuel efficiency of the vehicle can be measured in a variety of driving cycles, including the New European Driving Cycle (NEDC), Japanese JC-08, and FTP-75 (Federal Test Procedure). The type of vehicle used in fuel economy evaluation in the same cycle plays a significant role. Fuel consumption rates for the same vehicle measured in these driving cycles vary due to the differences in the cycles. Thus, to assess the effect of the lubricant on fuel efficiency in various cycles, the fuel consumption is measured relative to a reference oil.