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Technical Paper

The Virtual Engine Test

2001-05-07
2001-01-1905
In API engine oil licensing, a candidate oil must meet the performance requirements of category defined engine tests. The reason for the engine tests is to assess the capability of the candidate oil in field performance. Unfortunately, due to the time consuming and expensive nature of most engine tests, a candidate oil is typically run only once or twice in an attempt to meet the performance requirements. Given that the results from most engine tests have large amounts of variability, the assessment of the candidate oil in several tests, although adequate, is obviously not perfect or inexpensive. The Virtual Engine Test is a process in which the time and expense of category defined engine tests may be reduced while maintaining, or even improving, the assessment of the candidate oil capability.
Technical Paper

Mechanical Degradation of Viscosity Modifiers in Heavy Duty Diesel Engine Lubricants in Field Service

2003-10-27
2003-01-3223
Modern multi-grade engine lubricants are formulated to “stay in grade” during field service. Viscosity loss during the early stages of lubricant life is commonly believed to be caused by mechanical degradation of the viscosity modifier in the engine [1]. The Kurt Orbahn shear stability bench test (ASTM D 6278, 30 cycles) has been the industry standard predictor of viscosity loss due to polymer shear in heavy duty diesel engine lubricants. However, the Engine Manufacturers' Association (EMA) has expressed some concern that it underestimates the degree of polymer shear found in certain engines in the field, such as the Navistar 6.0L HEUI (Hydraulic Electronic Unit Injector) Power Stroke engine; a more severe bench test would serve to improve correlation with this and other similar engine designs. This paper offers a new approach for critically examining the relationship between the bench test and field performance.
Technical Paper

Combustion Modeling of Soot Reduction in Diesel and Alternate Fuels using CHEMKIN®

2001-03-05
2001-01-1239
A new gas phase kinetic model using Westbrook's gas phase n-heptane model and Frenklach's soot model was constructed. This model was then used to predict the impact on PAH formation as an indices of soot formation on ethanol/diesel fuel blends. The results were then compared to soot levels measured by various researchers. The ignition delay characteristics of ethanol were validated against experimental results in the literature. In this paper the results of the model and the comparison with experimental results will be discussed along with implications on the method of incorporation of additives and alternative fuels.
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