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It has been reported that multigrade oils save fuel and oil. In medium-speed diesel railroad engines, the claimed savings being about 20% oil and 1% fuel. Oil consumption in such engines has previously been measured in locomotives operating in commercial service, and subject to the errors and logistics problems associated with such procedures. We now report the results of an oil consumption test run in a full-scale engine on a dynamometer in a test cell. The technique involved estimation of the mass of oil in the engine by the amount of dilution of a pre-measured quantity of magnesium when added to the crankcase. This method accounts for oil in the entire system including the sump, filter housing, and oil galleries. The results indicated at least a 15% oil consumption benefit for an SAE 25W-40 oil versus SAE 40. The paper presents the technique, the mathematical model used, and a rigorous statistical analysis to support the conclusions.

Diesel engine sludge has received wide coverage in the literature for truck, bus, and passenger car applications. Aside from creating a dirty working environment, it has been associated with filter plugging and, in extreme cases, oil gelation. Sludge is also important to North American locomotive operators where zinc-free oils are used. In recent years, some operators have experienced sludging and filter plugging. Here we discuss railroad industry trends affecting the engine oil, review the literature on sludge formation, and characterize used oil and sludge from railroad applications. We then provide the results of a field test demonstrating the impact of the engine oil additive.

An intermittent sampling valve was used to investigate local fuel H/C ratio and species concentrations in an operating DI diesel engine. Additionally, predictions of carbon and hydrogen originating from particulates and nonmethane hydrocarbons (carbon and hydrogen remainders) were made by calculation. Sample H/C ratio was used to assess local fuel phase as gaseous or liquid. Evidence of intermediate species quenching in the lean region between spray plumes was found under low swirl. Reduction in the rate of penetration under high swirl may account for the observed loss in efficiency under this condition.