Browse Topic: Differential fluids

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A Passive Solution to Differential Transient Cooling Issues Using Phase Change Materials2016-01-000804/05/2016
Thermal management systems (TMS) of armored ground vehicle designs are often incapable of sustained heat rejection during high tractive effort conditions and ambient conditions. During these conditions, which mainly consist of high torque low speed operations, gear oil temperatures can rise over the allowable 275°F limit in less than twenty minutes. This work outlines an approach to temporarily store excess heat generated by the differential during high tractive effort situations through the use of a passive Phase Change Material (PCM) retrofit thereby extending the operating time, reducing temperature transients, and limiting overheating. A numerical heat transfer model has been developed based on a conceptual vehicle differential TMS. The model predicts the differential fluid temperature response with and without a PCM retrofit. The developed model captures the physics of the phase change processes to predict the transient heat absorption and rejection processes. It will be used to
Putrus, Johnathan, Jones, Stanley, Jawad, Badih, Kfoury, Giscard, Arslan, Selin, Schihl, Peter
Newtonian Multigrade Gear Lubricants: Formulation and Performance Testing82118002/01/1982
The use of high molecular weight polyalphaolefins makes possible the preparation of Newtonian multigraded lubricants. The preparation of a family of multigrade automotive gear oils, including a unique 75W-140 grade, is presented along with GL-5 performance testing and fuel economy demonstration under controlled conditions.
Watts, R. F., Willette, G. L.
Friction Characteristics of Controlled-Slip Differential Lubricants66077802/01/1966
Controlled-slip differentials (CSD) improve car operation under wheel slipping conditions. The performance of CSD's is dependent upon two criteria associated with clutch friction: “chatter” and “effectiveness.” “Chatter” is an undesirable noise which may occur during differential action. “Effectiveness” is a measure of the ability of the CSD clutches to transfer torque, during wheel slippage, to the wheel with the greater traction. The objective of this investigation was to definitely establish the cause of chatter, measure CSD effectiveness, and relate friction characteristics of lubricants to CSD operation. In tests with an instrumented car, it was found that both chatter and effectiveness are strongly influenced by the lubricant. Chatter occurred with lubricants that produced an increase in clutch friction with decreasing sliding speed. Chatter did not occur with lubricants containing friction modifiers which produced a decrease in clutch friction with decreasing sliding speed
Haviland, M. L., Goodwin, M. C., Rodgers, J. J.
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