Exhaust gas sensors for automotive emission control

The need for energy efficiency is leading to the growing use of additives that reduce friction in thin film boundary and mixed lubrication conditions. Several classes of such friction modifier additive exist, the main ones being organic friction modifiers, functionalised polymers, soluble organo-molybdenum additives and dispersed nanoparticles. All work in different ways. This paper reviews these four main types of lubricant friction modifier additive and outlines their history, research and the mechanisms by which they are currently believed to function. Aspects of their behaviour that are still not yet fully understood are highlighted.

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Friction Modifier Additives

Modern engine lubricant specifications include compositional constraints in terms of the permitted level of sulphated ash, phosphorus and sulphur (SAPS). This necessitates a reduction in the concentration of the additive zinc dialkyldithiophosphate (ZDDP) used in engine oils, and there is currently great interest in identifying anti-wear additives that contain low or zero SAPS to partially or wholly replace ZDDP.

This paper reviews the main chemical classes that are reported in the literature as potential low- or zero-SAPS anti-wear agents. There are many such possible additives, although none appears to be quite as versatile as ZDDP. Instead, combinations of anti-wear and extreme pressure additives are likely to be employed in the future. The literature reveals a strong imbalance in the amount and depth of research carried out on the various additive types, with a great deal of research on a few classes of additives and very little recent work on most others. Copyright © 2007 John Wiley & Sons, Ltd.

Low- and zero-sulphated ash, phosphorus and sulphur anti-wear additives for engine oils

An imaging apparatus and related method comprising a detector located a distance from a source and positioned to receive a beam of radiation in a trajectory; a detector positioner that translates the detector to an alternate position in a direction that is substantially normal to the trajectory; and a beam positioner that alters the trajectory of the radiation beam to direct the beam onto the detector located at the alternate position

Systems and methods for imaging large field-of-view objects

Oil-derived contaminants on light-off catalysts from high mileage taxis were characterized by a variety of physical and chemical methods. The contaminants (mostly phosphates) deposit in a strong axial gradient from the front to the back of the monolithic catalyst channels. Two major forms of phosphorus contamination were observed: (1) an overlayer of Zn, Ca, and Mg phosphates, and (2) aluminum phosphate within the washcoat. The data also suggest the formation of cerium(III) phosphate. Laboratory catalytic reaction measurements on core samples from the taxi catalysts confirm a strong deactivating effect due to the phosphorus contamination. The activity improves dramatically after removing phosphorus via an oxalic acid wash.

Characterization of phosphorus-poisoned automotive exhaust catalysts

Engine Oil Additive Effects on Deactivation of Monolithic Three-Way Catalysts and Oxygen Sensors

Piston ring moving zone in the cylinder is one of the most critical lubrication regimes in diesel engines. This area is susceptible to combustion substances. In particular, abnormal wear is occasionally detected due to Exhaust Gas Recirculation (EGR) system equipment. In Japan, NO/sub x/ emission requirements for passenger car diesels have become more stringent effective October 1, 1986. OEMs tend to apply EGR systems to reduce NO/sub x/ in exhaust gas. In order to identify the phenomenon of abnormal cylinder wear of EGR equipped engine, engine bench tests were conducted under varied conditions in EGR equipment, cooling water temperature and fuel sulfur content. The test results suggest that wear caused at low temperature is mainly corrosive wear attributable to sulfuric acid formed by reaction with fuel sulfur and condensed water. Engine oil additives behavior against sulfuric acid was studied for control of corrosive wear and excellent CD 10W-30 engine oil was developed by selection of additives from the viewpoint of capability to neutralize sulfuric acid. The developed product demonstrated very good wear protection performance in the bench tests using EGR equipped engines.

Cylinder wear mechanism in an EGR-equipped diesel engine and wear protection by the engine oil

Effects of phosphorus and ash contents of engine oils on deactivation of monolithic three-way catalysts and oxygen sensors

Hydraulic fluids for automobile suspensions are described. They contain, as a base oil, a mixed oil which in turn contains 70-90 wt. % of an olefin oligomer and 10-30 wt. % of a diester obtained by condensation of an aliphatic dibasic acid having 4-14 carbon atoms and an alcohol having 4-14 carbon atoms. The hydraulic fluids also comprise a phosphate ester friction modifier to improve the friction characteristics and antiwear characteristics in an initial stage and at least one friction modifier selected from the group consisting of phosphite esters and phosphoric ester amine salts to retain low friction characteristics over a long period of time.

Kenyu Akiyama

Papers

Engine Oil Additive Effects on Deactivation of Monolithic Three-Way Catalysts and Oxygen Sensors

Cylinder wear mechanism in an EGR-equipped diesel engine and wear protection by the engine oil

Effects of phosphorus and ash contents of engine oils on deactivation of monolithic three-way catalysts and oxygen sensors

Hydraulic fluids for automobile suspensions

Fuel Efficiency of SAE 5W-20 Friction Modified Gasoline Engine Oil