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Interactions between a Zinc dialkyldithiophosphate (ZDP) and three different commercially available succinimide dispersants were observed through changes in solutions behavior, as determined by viscometry and Fourier Transform Infrared spectroscopy (FTIR), and four-ball tests. The viscometric response observed for two component blends of ZDP and succinimide dispersant in white oil changed as a function of the molar Zn to N ratio, indicative of specific interactions. The break in the viscometric response curve occurred at Zn:N=0.13 for all three succinimide dispersants. FTIR spectra of the same ZDP-dispersant blends were examined and similar Zn:N dependencies were observed. Four-ball tests measuring wear scar diameter, seizure load and weld load showed a dependence on the Zn to N ratio similar to that observed by viscometry. At very low Zn to N ratios wear and seizure load were decreased, while at higher ratios the seizure and weld loads were increased over that for ZDP alone.

Despite the many years of widespread use of the BMW Intake Valve Deposit (IVD) vehicle test, relatively little has been published quantifying the variation in the test procedure. This paper presents an analysis of the variability in the BMW test. Though results from 8045 km (8K; 5,000 mile) tests rather than 16090 km (16K; 10,000 mile) are highlighted due to the size of the available database and relative sensitivity of the data, analysis suggests that variation at 8K is representative of 16K variation. A square root transformation of average deposit weight at 8K, though more cumbersome than the more common log transformation, is found to be the most appropriate way to eliminate the dependence of variation on the absolute level of deposits. Within-car variation is found to account for over half of the test-to-test variation, contradicting the notion that car-to-car differences are the dominant source of variability.

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.

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.

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).

Intentionally adding water to oil, in the laboratory, provides an indication of the oil's ability to tolerate the presence of water. Various characteristics, such as emulsion, haze or separation, may be observed. Some blends of oil and water have been shown to form structures when left undisturbed. A visual, qualitative, storage test is capable of detecting this phenomenon as the presence or absence of structure. However, the time frame of formation can be on the order of days or weeks and is sensitive to handling and temperature effects. Quantitative methods are required for any evaluation of chemistry, temperature and handling effects on the rate and strength of structure formation. This paper describes rheological and electrical methods which directly and indirectly measure the tendency to form a structure at the molecular level, yielding rate of formation and strength information.

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.

Information relative to oil thickening has been developed in road tests. Typical operating temperatures, as well as the length of time required to thicken oils in these tests, are described. A laboratory test procedure has been developed that shows a good degree of correlation with this field service. The effect of test conditions such as jacket temperature and piston ring design on oil thickening in the laboratory are described.

A major drive to develop methanol-fueled vehicles began with the 1973 oil embargo. Early work with dedicated methanol-fueled vehicles demonstrated that lubricant choice influenced engine durability. The qualities desired were not defined by the gasoline engine oil classification system in place at the time. As a result oils were developed which optimized those properties deemed desirable for methanol fuel. The advent of fuel sensors made it possible to design a vehicle which can operate on gasoline or gasoline with varying levels of methanol without intervention by the operator. This created a need for a lubricant that can handle a diversity of methanol/gasoline mixtures as well as conventional gasoline. The paper reviews some of the lubricants that have been used in prototype methanol-capable vehicles and the improvement of these formulations to meet the latest gasoline engine performance criteria while maintaining satisfactory methanol performance.

In order to assess the field needs of engine oils to be used in methanol-fueled vehicles, six oils were run in a fleet test over a ten-month period under short-trip service conditions. The results from the field test were compared with results with the six oils in the laboratory engine tests which have been used to predict field performance with methanol fuel. A lack of correlation between the field test and the laboratory engine tests suggests that the laboratory tests need revisions to better serve field needs.

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.

Additives are an integral part of today's fuels. Together with carefully formulated base fuel composition, they contribute to efficiency, dependability and long life of gasoline and diesel engines. As a primer, this paper describes the range of chemical additives formulated for gasoline and diesel fuel and their effects. Specific functions and benefits of additives, typical use levels, and test methods for evaluation are discussed. Additive usage may be divided into three major categories: a) to satisfy desired levels of performance in engines, b) to insure delivery of uncontaminated, on-specification fuels to the end user and c) achieve necessary chemical/physical properties as manufactured by the refiner.

Additives are an integral part of today's fuels. Together with carefully formulated base fuel composition, they contribute to efficiency, dependability and long life of gasoline and diesel engines. As a primer, this paper describes the range of chemical additives formulated for gasoline and diesel fuel and their effects. Specific functions and benefits of additives, typical use levels, and test methods for evaluation are discussed. Additive usage may be divided into three major categories: a) to satisfy desired levels of performance in engines, b) to insure delivery of uncontaminated, on-specification fuels to the end user and c) achieve necessary chemical/physical properties as manufactured by the refiner.

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.

Recent commercial specification revisions for automatic transmission fluids (ATFs) have focused upon more stringent friction requirements. More stringent friction durability characteristics are assessed using the SAE No. 2 tester. The commercial specifications do not include provisions to evaluate low speed friction characteristics, which have been shown to relate to torque converter shudder. This paper focuses upon effective use of the Falex 6 Multispecimen Tester to evaluate friction durability and to evaluate low speed friction characteristics in conjunction with low speed friction apparatus (LVFA) testing. Falex 6 testing agreed with torque fade observed in SAE No. 2 tests. Low speed stick-slip durability characteristics were effectively differentiated for a number of field ATFs. Falex 6 testing coupled with LVFA testing was shown to correlate with field experience and other test methods related to torque converter shudder.

Accurate, timely field test results are necessary to develop and validate lubricants meeting frequently changing performance requirements. Field tests can also provide valuable information about performance deficiencies (e.g., soot related wear) which are not apparent in laboratory development tests. Since field tests are time intensive and increasingly expensive, it is imperative that the data generated provide meaningful results with reasonable expenditures. The data generation and analysis process are being constantly improved according to the principles of quality management. Part of the process improvement focuses on accurate, realistic treatment of the data since more variation is typically observed in field tests than in laboratory tests. One of the most difficult analytical processes occurs with oil consumption data.

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 effects of gasoline composition, as represented in typical regular and premium unleaded gasolines and fuel additives, on Combustion Chamber Deposits (CCD) were investigated in BMW and Ford tests. In addition, the influences of engine lubricant oil and ethanol oxygenate on CCD were examined in Ford 2.3L engine dynamometer tests. Also, additive effects of packages based on mineral oil fluidizers versus synthetic fluidizers were studied in several different engines for CCD. Finally, a new method for evaluating the effect of fluidizers on valve sticking is introduced.

A test method has been developed which provides for the rapid measurement of the scuffing performance of diesel fuel using the Ball-On-Cylinder Lubricity Evaluator (BOCLE). A test can be completed in less than one hour. Data has been generated indicating that the method achieves good discrimination between fuels of varying lubricity and correlates well with fuel performance as measured in pump tests.

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.