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Technical Paper

The Effect of Friction Modifiers and DI Package on Friction Reduction Potential of Next Generation Engine Oils: Part II Aged Oils

Engine oil plays an important role in improving fuel economy of vehicles by reducing frictional losses in an engine. Our previous investigation explored the friction reduction potential of next generation engine oils by looking into the effects of friction modifiers and dispersant Inhibitor packages when engine oil was fresh. However, engine oil starts aging the moment engine start firing because of high temperature and interactions with combustion gases. Therefore, it is more relevant to investigate friction characteristics of aged oils. In this investigation, oils were aged for 5000 miles in taxi cab application.
Journal Article

Proof-of-Principle Investigation into the Use of Custom Rapid Aging Procedures to Evaluate and Demonstrate Catalyst Durability

The application of accelerated catalyst aging procedures on an engine dynamometer test bed for the purpose of demonstrating catalyst durability is examined. A proof-of-principle approach is followed using catalysts from vehicles certified to U.S. Tier 2 Bin 4 and California SULEV 2 levels. Accelerated durability demonstration methods based upon conventional fuel cut cycles were employed to age catalysts to levels predicted by quantification of thermal catalyst bed severity on the Standard Road Cycle (SRC) relative to the fuel cut aging cycle using the Bench Aging Time (BAT) equation. Emissions deterioration on the accelerated aging cycle is compared to the automobile manufacturers' certification values and to whole vehicle emissions performance results from several different in-use vehicle fleets. The influence of technology on whole vehicle emissions levels and deterioration characteristics is also evaluated.
Technical Paper

Physicochemical Mechanisms for Fluoroelastomer Seal Failures

Elastomer compatibility is an important property of lubricants. When seals degrade oil leakages may occur, which is a cause of concern for original equipment manufacturers (OEMs) because of warranty claims. Leakage is also a concern for environmental reasons. Most often, the mechanical properties and fitting of the oil seals is identified as the source of failure, but there are cases where the interaction between the lubricant and the seal material can be implicated. The performance of seal materials in tensile testing is a required method that must be passed in order to qualify lubricant additive packages. We conducted an extensive study of the interactions between these elastomeric materials and lubricant additive components, and their behavior over time. The physicochemical mechanisms that occur to cause seal failures will be discussed.
Journal Article

Lubricants for (Hybrid) Electric Transmissions

In electric or hybrid electric transmissions, the transmission fluids can be in contact with the parts of the electric motors, for example, electrical windings in the stators in order to efficiently cool the electric motors and to insulate the electrical parts to prevent a short circuit of the electric motors. The transmission fluids must therefore have low electrical conductivities [1,2,3,4,5,6,7,8,9]. Transmission fluids contain dispersants, which can be reaction products of hydrocarbyl substituted carboxylic acids or anhydrides and amines. These dispersants can be further post-treated with boron and phosphorus compounds to improve friction and anti-wear properties. Certain dispersants, which have nitrogen content up to 10,000 ppm by weight, and boron plus phosphorus to nitrogen ((B+P)/N) weight ratios of from 0.1 to about 0.8 : 1.0, were found to be effective to provide low electrical conductivities less than 1,700 pS/m [10].
Journal Article

Formation of Intake Valve Deposits in Gasoline Direct Injection Engines

Gasoline direct-injection (GDI) engines have a well-known propensity to form intake valve deposits (IVD), regardless of operator service, engine architecture, or cylinder configuration. Due to the lack of a fuel-washing process that is typical of Port Fuel Injected (PFI) engines, the deposits steadily accumulate over time and can lead to deterioration in combustion, unstable operation, valve-sticking, or engine failure. Vehicles using these engines are often forced to undergo expensive maintenance to mechanically remove the deposits, which eventually re-form. The deposit formation process has not been well-characterized and there is no standardized engine test to study the impact of fuel or lubricant formulation variables. To meet this need, a proprietary vehicle-based GDI-IVD test that is both repeatable and responsive to chemistry has been developed.
Technical Paper

Correlation of the Sequence VID Laboratory Fuel Economy Test to Real World Fuel Economy Improvements

When gasoline-fueled vehicles are operated in consumer service, the oil used to lubricate the engine plays a key role in engine cooling, reducing friction, maintaining efficient operation, and optimizing fuel economy. The effects of normal vehicle operation on oil deterioration have a direct impact on fuel consumption. The authors have observed substantial differences between the deterioration of engine oil and resulting fuel economy under real-world driving conditions, and the deterioration of oils and resulting fuel economy in the standard laboratory test used to assess fuel economy in North America, the Sequence VID engine test (ASTM D7589). By analyzing the data from vehicles and comparing these data to the Sequence VID the authors have proposed and evaluated several changes to the Sequence VID test that improve the correlation with real-world operation and improve test discrimination.