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Modern agriculture has evolved dramatically over the past half century. To be profitable, farms need to significantly increase their crop yields, and thus there are amplified demands on farming equipment. Equipment duty cycles have been raised in scope and duration, as the required output of the agricultural industry to sustain a growing population has stimulated the need for further advances in effective productivity gains on the farm. The mainstay mechanical assistant to the farmer, the tractor, has also evolved with the changes in modern agriculture to meet the requirements of these newer tasks. Larger, more capable vehicles have been introduced to help farmers efficiently meet these demands. At the same time, the current generation of tractor diesel engine lubricants has facilitated high levels of performance in the agricultural equipment market for many years. This is a testament to the role modern lubricants play in productivity in such a critical industry.

To meet increasingly stringent emissions and fuel economy regulations, many Original Equipment Manufacturers (OEMs) have recently developed and deployed small, high power density engines. Turbocharging, coupled with gasoline direct injection (GDI) has enabled a rapid engine downsizing trend. While these turbocharged GDI (TGDI) engines have indeed allowed for better fuel economy in many light duty vehicles, TGDI technology has also led to some unintended consequences. The most notable of these is an abnormal combustion phenomenon known as low speed pre-ignition (LSPI). LSPI is an uncontrolled combustion event that takes place prior to spark ignition, often resulting in knock, and has been known to cause catastrophic engine damage. LSPI propensity depends on a number of factors including engine design, calibration, fuel properties and engine oil formulation. Several engine tests have been developed within the industry to better understand the phenomenon of LSPI.

Motorcycle manufacturers have recognized that highly friction modified passenger car oils can be deleterious to clutch performance, leading to clutch slippage. To address this issue, a JASO specification for four-stroke motorcycle oils was developed in 1999, categorizing oils into high friction oils termed JASO MA and low friction oils termed JASO MB. The high friction oils were preferred for most motorcycles where the engine oil also lubricates the clutch and gears. New motorcycle transmission technologies have increased the number of dry clutch applications which has led to an increased demand for JASO MB oils to improve fuel efficiency. While JASO MB oils contain friction modifiers to improve initial fuel economy, the motorcycle specifications have not addressed the fuel economy durability of motorcycle oils.

This paper is part one of a longer term comparison of viscosity modifier behavior in modern automotive gear oil (AGO) fluids and the impact of these properties on fluid efficiency and durability. This first installment will compare the rheological properties, including EHD film thickness and traction coefficients, of the fluids across broad operating temperature, shear and load regimes and correlate these findings with rig efficiency testing. The effects of traction, EHD film thickness and high shear rheology on operating temperature are well documented and it is of particular interest to determine the extent to which different viscosity modifiers can beneficially impact these properties compared to a Brightstock-based SAE 80W90 grade fluid. The efficiency improvements of a VM would be for naught if it were not sufficiently shear stable and so comparisons are made between shear stable VM technologies.

Requirements to reduce emissions and improve vehicle fuel economy continue to increase, spurred on by agreements such as the Kyoto Protocol. Lubricants can play a role in improving fuel economy, as evidenced by the rise in the number of engine oil specifications worldwide that require fuel economy improvements. A novel friction modifier technology has been developed to further improve vehicle fuel economy. The development of this novel friction modifier technology which contains only N,O,C,H was previously published along with the initial demonstration of performance in motorized Toyota engines. In order to validate this performance in fired engine tests, oil was evaluated in a Toyota Corolla Fielder with a 1500 cc gasoline engine. Testing was conducted in the Japanese 10-15 and JC08 modes, as well as the European EC mode, and the US FTP mode.

A discriminating dynamometer-based test was developed for evaluating cold start and warmup engine performance based on in-cylinder pressure measurements. The dynamometer test offers advantages in time required, flexibility and reduced variability over the vehicle procedure on which it was based. A parametric study on fuel driveability index (DI), ethanol content and intake valve deposit (IVD) rating demonstrated that each of these parameters had a statistically significant impact on engine cold start performance. Simple numerical offsets to fitted models based on oxygen content of the fuel did not account for the difference in engine performance of hydrocarbon-only versus ethanol-containing fuels. The effect of IVD on engine performance did not appear to depend on the DI of the fuel. The benefits of cleaner valves are seen even in fuels of very low DI.

The lubricant is a key component in the successful operation of a manual transmission, but it is important that the interactive effects with the friction material are understood. This paper examines the effect of several key additive components on the friction and wear performance of a single sinter composition in a carefully controlled laboratory test. In addition, the test method allows one to develop information about the shift behavior of the fluid-synchronizer material combination which provides useful information about shift quality. From the original experimental design program a predictive model was developed and an optimized formulation was tested as a validation of the results.

Extended drain of axle and transmission lubricants has gained wide acceptance in both passenger car and commercial vehicle applications. Understanding how the lubricant changes during extended drain operations is crucial in determining appropriate lubricants and drain intervals for these applications. A suitable aging screen test with an established relationship to field performance is essential. Over the years numerous methods have been studied (DKA, GFC, ISOT, ASTM L-60) with varying degrees of success1,2,3. Current methods tend to be overly severe in comparison to field experience, hence the need for further work in this area. As a result of recent work, a lubricant aging test method has been developed which shows good correlation with field experience, giving us an effective tool in the development of long drain oils.

Water-emulsified diesel fuel technology has been proven to reduce nitrogen oxides (NOx) and particulate matter (PM) simultaneously at relatively low cost compared to other pollution-reducing strategies. The value of this technology is that it requires absolutely no engine adjustments or modifications to reduce harmful emissions. Technologies that break the NOx -particulate trade-off are virtually non-existent, therefore understanding how the water contained in an emulsified fuel can reduce both NOx and PM simultaneously is critical. To understand this phenomenon, emulsified fuels with varying water levels (0 to 20%) were evaluated in a multi-cylinder marine engine using three different injection timings. This testing in an actual engine confirms that as the water level is increased the amount of NOx and PM are reduced without compromising engine performance.

The relationship between 76 Racing and NASCAR allowed 76 Lubricants Company to work closely with Richard Childress Racing (RCR) and The Lubrizol Corporation in the development of oil screening and analytical test procedures which permit rapid evaluation of potential top-tier NASCAR race oils. The oils were designed to meet the challenge of increasingly severe engine operating parameters. This paper will discuss dynamometer testing and how properties of the oil such as viscosity grade, base fluid, and additives affect engine durability in the dynamometer test program and performance at the track in NASCAR Winston Cup Racing. Areas of growing concern include the cam/lifter contact, ring/liner contact, wrist pin/pin bore and wrist pin bushing contacts. Racing lubricants must withstand these harsh conditions for periods of 3-4 hours of continuous running.

Inconsistent fuel filter life is a problem that continues to plague most heavy-duty diesel fleets. It has been proven that fuel filter life can be strongly influenced by the thermal and oxidative stability of diesel fuel that is being filtered. Filters consistently exposed to diesel fuels that produce a tar-like substance in abundance upon heating (sometimes termed “asphaltenes”) will plug far more rapidly than filters exposed to diesel fuel that does not easily form these tar-like substances. Fuel additives have long been used to maintain fuel system cleanliness and to improve diesel fuel stability. It follows logically that such additives could have a positive impact on fuel filter life by maintaining the cleanliness of the fuel filtration media. This paper reviews the laboratory evaluations and field tests that were run to compare fuel filter life in both the presence and absence of diesel fuel additives.

Driven by global demands for improved fuel economy and reduced emissions, significant improvements have been made to engine designs and control systems, vehicle aerodynamics, and fuel quality. Improvements, such as the continuously slipping torque converter, have also been made to automatic transmissions to increase vehicle efficiency. Recently, belt-continuously variable transmissions (b-CVTs) have been commercialized with the promise of significant fuel economy improvements over conventional automatic transmissions. Automotive traction drive transmissions may soon join belt-CVTs as alternative automatic transmission technology. Much of the information reported in technical and trade publications has been on the mechanics of these traction drive systems. As automotive traction drives move closer to commercial reality, more attention must be given to the performance requirements of the automotive traction fluid.

This work presents a follow-up to previous efforts by the authors to investigate the susceptibility of gasoline direct injection (g-di) engines to deposit formation and the effect of those deposits on vehicle performance. A series of injector keep clean and clean up tests in base and additized fuels utilizing the ASTM D 5598 cycle provided a range of injector fouling levels. It is found that the g-di engine employed here is more susceptible to injector deposits than even the sensitive port fuel injected (PFI) engine used as industry reference in the D 5598 procedure. Injector keep clean and clean up performance of several representative deposit control chemistries are evaluated. In order to determine the effect of injector fouling on performance, emissions and driveability tests are performed on the vehicles at varying levels of injector fouling. Regulated emissions, particulates, fuel consumption and driveability are all shown statistically to be linked to injector fouling.

In API engine oil licensing, candidate oils must meet the performance requirements of category defined engine tests. While API category engine tests are developed to target a theoretical performance standard, it is rare that the cost to test and approve oils is understood. Given that engine tests are an integral part of oil evaluation, understanding of engine test value is necessary. Therefore, measurements of value are presented as Unbiased Engine Test Evaluation (UETE). UETE evaluates an engine test's draw on time and money resources by estimating the average number of tests required before a candidate oil will pass the category defined engine tests. A pilot study using the API CH-4 Category is presented.

Low temperature flow improvers help refiners meet diesel fuel cold flow specifications and optimize profits. However, some additives, cloud point depressants in particular, are under scrutiny since there have been cases where they interacted with other cold flow improvers and became less effective at depressing the cloud point of the diesel fuel[1]. This second paper in a series of studies[2] examines what effect mixing cloud point depressed diesel fuel with other cloud point depressed diesel fuel or with diesel fuel diluted with kerosene will have on the resultant fuel mixture's cloud point. The data show that cloud point depressants can be used safely and effectively with kerosene blended fuels and in conjunction with other cloud point depressants.

The International Lubricant Standardization and Approval Committee (ILSAC) GF-2 specification requires Passenger Car Motor oils to provide enhanced fuel economy in a modern low friction engine (ASTM Sequence VIA). The durability of this fuel economy improvement is becoming increasingly important and will be address in the successor to the Sequence VIA, the Sequence VIB, which is currently under development for ILSAC GF-3. Previous investigations have indicated that the choice of detergent system and friction modifier has a large impact on the fuel economy of a lubricant. As a result of a study undertaken to further investigate these effects in a 1994 Ford Crown Victoria running the EPA Federal Test Procedure, a significant impact on tailpipe emissions was discovered. Detergent system affected both regulated emissions (hydrocarbon (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) emissions), and non-regulated emissions (carbon dioxide emissions).

Interactions between automatic transmission fluid (ATF) components and composite friction materials and their effect on friction system performance continues to be an active area of interest to the automotive industry. A more fundamental understanding is needed of how base fluids, ATF additives, friction materials, and transmission design interact to produce the observed transmission system performance and durability. We herein report results from investigations carried out using a relatively thermo-oxidatively stable polyalphaolefin (PAO) base fluid treated with components representative of several additive types we previously reported to have significant negative effects on frictional performance. Secondly, we investigated a conventionally refined 150 N base oil treated with a calcium sulfonate detergent previously shown to improve friction performance.

Our basic understanding of the chemical and physical nature of soot, its interaction with lubricant components and its role in promoting wear and oil thickening in heavy duty diesel engines continues to grow. Our current study in the GM 6.5L engine focuses on examining the effects of variations in base stock type (Group I vs. Group II), viscosity index improver or viscosity modifier (VM) chemistry (OCP vs. dispersant OCP), zinc dithiophosphate (ZDP) type and dispersant type (low MW vs. high MW) on roller follower wear, viscosity growth and other measured responses. In this study, more robust fluids were tested producing very low wear results and minimal viscosity increase of the lubricant. Fluids containing dispersant OCP (DOCP) and high MW dispersant produced a lower degree of wear, whereas varying the ZDP type (1° vs. 2°) showed no effect on wear. The use of Group II base stocks was associated with significantly lower viscosity increases.

The international Lubricant Standardization and Approval Committee (ILSAC) GF-2 specification requires Passenger Car Motor Oils to provide enhanced fuel economy in a modern low friction engine (ASTM Sequence VIA). In previous SAE publications the authors have studied the boundary lubrication regime and documented the impact of friction modifiers and antiwear additives on Sequence VIA fuel economy. This paper shifts the focus to the hydrodynamic lubrication regime and details fundamental studies of viscosity modifiers and base oils on fuel economy as measured by this low friction engine. The viscosity modifiers were found to have surprisingly little impact on this test, while moving to base oils of higher viscosity index improved fuel economy as might be theoretically expected. A study of formulating SAE 5W-30 motor oils with base oils of increasing viscosity index showed the optimum fuel economy was able to be obtained with a high viscosity index base stock.

This paper describes the development of a image analysis system that can be used to rate injectors from the Cummins L10 Injector Depositing Test. In the procedure, injectors are mounted on a computer controlled turntable and scanned using a CCD camera focused on the labyrinth flow area of the injector. The scanned monochrome images are processed and assigned an average gray scale rating. Results from the image analysis system are compared to the modified CRC Piston and Ring Rating method currently used within the Cummins test procedure. To do this, a series of injectors that have been rated by trained raters at a recent workshop were also rated via the image analysis system. The image analysis system ratings demonstrated a strong correlation (R = 0.85) to the CRC ratings. Using these same injectors, the image analysis method shows improvements in repeatability and reproducibility of approximately 50% over the current procedure.