Donald J. Smolenski

Antiwear performance and mechanism of an oil-miscible ionic liquid as a lubricant additive.

An ionic liquid (IL) trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate has been investigated as a potential antiwear lubricant additive. Unlike most other ILs that have very low solubility in nonpolar fluids, this IL is fully miscible with various hydrocarbon oils. In addition, it is thermally stable up to 347 °C, showed no corrosive attack to cast iron in an ambient environment, and has excellent wettability on solid surfaces (e.g., contact angle on cast iron <8°). Most importantly, this phosphonium-based IL has demonstrated effective antiscuffing and antiwear characteristics when blended with lubricating oils. For example, a 5 wt % addition into a synthetic base oil eliminated the scuffing failure experienced in neat oil and, as a result, reduced the friction coefficient by 60% and the wear rate by 3 orders of magnitude. A synergistic effect on wear protection was observed with the current antiwear additive when added into a fully formulated engine oil. Nanostructure examination and composition analysis revealed a tribo-boundary film and subsurface plastic deformation zone for the metallic surface lubricated by the IL-containing lubricants. This protective boundary film is believed to be responsible for the ILs antiscuffing and antiwear functionality.

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.

Determination of differences in tribological behavior and surface morphology between electrodeposited and traditional phosphate coatings

Abstract Traditional phosphate coatings are formed by submersing iron or steel in an aqueous solution of phosphoric acid and other chemicals without applying an axternal voltage. In contrast, the newly developed electrocoated iron phosphate films described in this paper are deposited electrochemically from an oil containing mixed organic phosphates. The friction characteristics and surface morphology of the electrodeposited iron phosphate films on piston ring specimens were compared with those of traditional phosphate coatings. The electrodeposited film consists of an amorphous structure and provides lower friction than does either traditional crystalline manganese or iron phosphate coatings. These results indicate that surface morphology has a strong influence on friction-reducing film formation mechanisms.

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.

Development of the ASTM Sequence IIIE Engine Oil Oxidation and Wear Test

The ASTM Sequence IIID engine-dynamometer test has been used to evaluate the high-temperature protection provided by engine oils with respect to valve train wear, viscosity increase (oil thickening), deposits, and oil consumption. The obsolescence of the engine used in this test along with the need to define even higher levels of performance associated with a new oil category (SG) prompted efforts at developing a replacement test. This paper describes the hardware and procedure development of this replacement test, the ASTM Sequence IIIE test. Test precision and correlation with field and Sequence IIID results on a series of reference oils is also discussed.

EFFECT OF ENGINE OIL ZINC DITHIOPHOSPHATE (ZDP) ADDITIVE TYPE ON CAM AND LIFTER WEAR IN TAXI SERVICE

The major phosphorus-containing compounds in engine oil are zinc dithiophosphates (ZDPs), which act both as antioxidants and antiwear agents. To reduce engine oil phosphorus concentrations without compromising engine durability, and thereby reduce phosphorus poisoning of emission control devices, an optimum ZDP mixture should be used. A 160,000-km taxi test was conducted to determine the relative camshaft and lifter wear protection provided by several ZDPs and ZDP mixtures. Wear protection was poorest with aryl ZDPs (which are thermally stable, as determined by differential scanning calorimetry (DSC)), intermediate with long-chain primary alkyl ZDPs (which are thermally unstable), and best with short-to-medium chain secondary or short-chain primary alkyl ZDPs (which are of intermediate thermal stability). Sequence IIID test results on analogs of the field test oils correlated fairly well with taxi test results; sequence V-D test results did not correlate as well.

Characterization and Tribological Evaluation of 1-Benzyl-3-Methylimidazolium Bis(trifluoromethylsulfonyl)imide as Neat Lubricant and Oil Additive

Selected physical and chemical properties and tribological data for a newly-developed, imidazolium-based ionic liquid (IL) are presented. The IL is soluble in the SAE 5W-30 oil up to a certain weight percentage, and is as a promising candidate for use in lubrication applications, either in its neat version or as an oil additive. Characterization of the IL included dynamic viscosity at different temperatures, corrosion effects on cast iron cylinder liners, and thermal stability analysis. The tribological performance was evaluated using a reciprocating ring-on-liner test arrangement. When used in neat version this IL demonstrated friction coefficient comparable to a fully formulated engine oil, and when used as an oil additive it produced less wear.Copyright