Shirley E. Schwartz

Development of an Automatic Engine Oil-Change Indicator System

To insure maximum engine life, it is essential that engine oil be changed as required. Some drivers are not aware that the oil should be changed, and others do not know how often to change it. To assist the driver in this regard, an automatic oil-change indicator was developed. In developing the oil-change indicator, it was found that oil temperature, vehicle mileage, engine resolutions, and changes in the physical and chemical properties of the oil during use all provided and indication of oil degradation. Based on these measurements, a mathematical model was developed which relates oil life to oil temperature and either vehicle mileage or engine revolutions. Computer hardware and software suitable for use in a vehicle were developed based on the mathematical model.

A Model for the Loss of Oxidative Stability of Engine Oil During Long-Trip Service, Part I: Theoretical Considerations

A model for the loss of oxidative stability of engine oil is presented in which the oil in an operating engine is assumed to be in one of three categories: oil which is lost from the system, oil in which the oxidative stability is reduced or lost as a consequence of exposure to harsh conditions, and the bulk of the oil which is neither lost nor reacted. Graphical examples are presented to show how various events or conditions in an engine, for example, oil consumption, oil additions, residual oil from the previous oil change period, and the presence of contaminants in the oil, affect the oils oxidative stability. Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991

A Model for the Loss of Oxidative Stability of Engine Oil During Long-Trip Service, Part II: Vehicle Measurements

Using equations developed in Part I, predicted values for the remaining oxidative stability of engine oil were compared to oil analysis results (oxidation induction time by differential scanning calorimetry) of engine oil from vehicle tests. In driving tests, the loss of oxidative stability of the engine oil followed logarithmic decay curves as predicted by the model. In addition, the model compensated for the loss of oxidative stability due to pulling a 900-kg trailer

Entry and retention of methanol fuel in engine oil

To ensure that vehicles do not suffer adverse consequences when high-methanol-content fuel (M100 or M85) is used, it is important to understand the ways that the use of this fuel affects various vehicle systems. For that reason, some of the changes which occur in the engine oil when using methanol fuel were investigated. During a single cold start with an extended cranking time, as much as six percent fuel entered the engine oil. Over a 15-minute period, the lubricating medium changed from engine oil to an oil-methanol-water emulsion. With multiple cold starts followed by a five-minute trip and ambient temperatures near freezing, the oil contained 19 percent volatile contamination. In addition, the oil contained elevated levels of water, lead, iron, chromium, and aluminum. Efforts need to be directed toward reducing the adverse consequences of methanol fuel.

Flow Characteristics of Hydraulic Fluids of Different Viscosities I. Flow in Valves: A Transition from Laminar to Turbulent Flow

The use of “high-water” or “95/5” hydraulic fluids is expanding from limited utilization in very special equipment to broader applications in general industrial hydraulic equipment. The fluids contain 95- to 99-percent water and have essentially the viscosity of water. Since hydraulic equipment is designed for use with fluids having an oil-like viscosity, the performance of hydraulic equipment will be affected by the use of high-water fluids. To study the effects of the low viscosity fluids on a hydraulic value, flow through the valve was measured as pressure, valve opening and viscosity were varied. Flow for any given set of test conditions could be categorized as belonging to one of five different domains. For each domain, a characteristic equation has been determined. Under some conditions of valve setting and pressure, different flow characteristics were found for the 95/5 fluid than were found or oil-like fluids. For example, at the largest valve opening, flow of the 95/5 fluid was predominantly turb...

Flow Characteristics of Hydraulic Fluids of Different Viscosities II. Flow in Pumps: Internal Leakage and Loss of Efficiency

A new type of hydraulic fluid, the high-water type, is being developed for use in industrial equipment which is currently using oil or oil-like fluids. In order to determine which factors affect the flow properties of high-water hydraulic fluids, a series of solutions ranging in viscosity from that of a water-glycol fluid (55 mPa·s or 250 SUS) to that of a high-water fluid (3 mPa·s or 35 SUS) was formulated by varying the amount of thickening agent. From flow rates of these fluids at known pressure and viscosity, the efficiency (percent loss of flow) was calculated. As would be expected, internal leakage from the high-pressure side of the pump to the low-pressure side was much greater with the 3 mPa·s fluids than with the 50 mPa·s fluids. Increasing the pump size increased pump efficiency at a given viscosity. Equations relating pressure, viscosity and flow for two types of internal leakage were developed by mathematical or graphical analysis of the experimental data. Presented at the 35th Annual Meeting ...

Mechanisms of engine wear and engine oil degradation in vehicles using M85 or gasoline

The results of several investigations indicate the extent to which driving cycle, oil formulation, and fuel type (either regular unleaded gasoline or M85) influence the nature and severity of engine-oil degradation and engine damage. Driving cycle greatly influenced mass loss of piston rings and main and connecting rod bearings. For example, short-trip, cold start service with M85 caused 80 times more wear of top piston rings per km of service than was observed in long-trip service with the same oil. The magnitude of engine oil degradation was also documented. Under freeway driving conditions, in which the engine oil warmed completely, service with M85 fuel caused approximately the same amount of oil degradation as was found with gasoline. In city service, several engine oil parameters (base number, accumulation of insoluble contaminants, viscosity) degraded twice as fast with gasoline as with M85. 9 refs., 17 figs., 3 tabs.

Flow Characteristics of Hydraulic Fluids of Different Viscosities III. Comparison of a Thickened High-Water Fluid to an Unthickened 95/5 Fluid and to a Water Glycol Fluid

95/5 hydraulic fluids (95 percent water, 5 percent additives) have a low viscosity, essentially that of water. In certain kinds of pumps, as the pressure is increased, the low viscosity of the 9515 fluids causes excessive internal leakage and loss of efficiency. In an effort to improve the efficiency of equipment and reduce leakage when using the 95/5 fluids, a polyoxyalkylene thickening agent was added to the 95/5 fluid. Flow rates in a pump system, shear stability, low shear viscosities, and effective high shear viscosities were measured for high-water fluids containing this thickening agent. Flow rates of an unthickened high-water fluid and of a water glycol fluid were determined in the same system for comparison. The thickened high-water fluid showed great improvements in volumetric efficiency over the unthickened high-water fluid. For example, at 4200 kPa pressure (600 psi) a 95/5 unthickened fluid had a 45 percent volumetric efficiency while a thickened 90/10 fluid had a volumetric efficiency of 78 ...