Abstract: An apparatus and method is disclosed for indicating useful life of motor vehicle angine oil during engine operation based on engine oil temperature without direct measurement thereof. Following the initiation of engine operation, engine oil temperature is calculated from a warmup equation until calculated engine oil temperature exceeds a warmup reference, whereupon it is calculated from an equilibrium equation, both of which equations being linear combinations of engine operating parameters other than engine oil temperature itself. The warmup equation includes a constant term, a reference temperature term fixed at the begining of engine operation and a term increasing proportionally with the number of engine cylinder firings. The equilibrium equation includes a constant term, an engine temperature term and a term proportional to engine speed and may also include a term proportional to an engine cooling factor.

Abstract: A number indicative of the number of engine revolutions corresponding to the useful life of the engine oil in a motor vehicle is stored in nonvolatile memory. As the vehicle is operated, the number is periodically decremented by an amount determined in relation to a penalty factor and the number of engine revolutions which occur in the period. The penalty factor is periodically updated and is determined in relation to the operating temperature of the engine oil, based on empirically determined data. The stored number represents the remaining life of the engine oil and is continuously displayed for the information of the operator. A warning lamp is lit to alert the operator to change the oil soon when the stored number is reduced to within 10% of the originally stored value. When the oil is changed, a reset switch is actuated and the number is reset to its original value.

Abstract: This invention relates to thickened high-viscosity water based hydraulic fluids. Such fluids are prepared by blending water, organic thickener and conventional hydraulic fluid additives. Organic thickeners tend to lose their thickening effect with time, and particularly when subjected to oxidizing agents, heat, prolonged use in a pump, etc. In accordance with the instant invention, preservation of the thickener, particularly with respect to viscosity loss, is achieved by blending with the final fluid a fluid concentrate, or the thickener itself, a compound selected from the group consisting of ethylene glycol, propylene glycol, propylene glycol polymers and copolymers containing at least 50 percent by weight of oxypropylene groups, a dimercaptothiadiazole, neodecanoic acid, a hindered phenol antioxidant and mixtures thereof.

Abstract: In accordance with the instant invention, a water-based hydraulic fluid, having improved anti-wear and corrosion inhibition properties can be obtained by blending neodecanoic acid with a conventional water-based hydraulic fluid composition.

Abstract: In accordance with the instant invention, a water-based hydraulic fluid, having improved low foaming properties can be obtained by blending 2-ethylhexanol with a conventional water-based hydraulic fluid composition.

Abstract: In accordance with the instant invention, a water-based hydraulic fluid, having improved anti-wear and corrosion inhibition properties can be obtained by blending neodecanoic acid with a conventional water-based hydraulic fluid composition.

Abstract: In accordance with the instant invention, a water-based hydraulic fluid, having improved viscosity can be obtained by blending a carboxylic acid with a thickened hydraulic fluid composition employing a thickener obtained by modifying a conventional polyether polyol thickening agent with an alpha-olefin epoxide or glycidyl ether having about 10 to 24 carbon atoms or mixtures thereof. Small amounts of higher molecular weight glycols may also be incorporated into the chain.