Browse Topic: Lubricant contamination
This ARP describes a gravimetric method for the determination of particulate contaminant in hydraulic fluids by the control filter technique. NOTE: With this method, detectable contamination levels down to 0.2 mg (7.0 × 10-6 ounces) per sample can be obtained with a standard deviation of ±0.1 mg (±3.5 × 10-6 ounces).
Over the years during which fluid filtration systems have been developing, many terms have come into use for descriptions of characteristics of filter media, filter assemblies, test methods, and test materials. Inevitably, some terms have been applied loosely, so that the same term may have different meaning to different people, or in different frames of reference. Recognizing the need for clearly defined terms, which can have only one meaning for all persons in all circumstances, so that documents dealing with standard methods of evaluation of filters will have only one interpretation, the Filter Test methods Subcommittee of the SAE Engine Committee has compiled this Glossary of related terms. No attempt has been made to produce an all-inclusive document, containing definitions of all terms related to all types of fluid filters. Instead, the Glossary is confined to the terms likely to be encountered in relation to filters for lubricating oil and fuels. At the same time, we have recognized that some terms are common to all types of fluid filters, and have been careful to avoid conflict with the definitions published by other standardizing groups. If not identical, the definitions of these terms are at least worded to convey an identical meaning, hopefully in fewer, simpler or more precise words. We hope that this effort will be effective in helping to eliminate the ambiguities which have resulted from imprecise use of terminology and filtration. This Glossary is referenced in the SAE filter test methods documents. Terms used in those documents are intended to have the definitions shown by this Glossary, and no other. As new terms and their definitions become associated with the science of filtration and are relevant to the documents prepared by this subcommittee, revisions to the Glossary will be made, either by issuance of addenda or by revision and republication of the entire document.
With the worldwide trend towards CO2 emission reduction, renewable fuels such as ethanol are gaining further importance. However, the use of ethanol as a fuel can bring some tribological impacts. Friction and wear of engine parts when lubricants are contaminated with ethanol are not very well understood. Within this scenario, the present paper introduces a new procedure to investigate the ethanol dilution on the performance of engine oils. Friction and wear of actual piston ring and liner were evaluated in a reciprocating test designed to emulate real thermomechanical conditions of both urban and highway car use. In addition to fresh oil, lubricant/ethanol emulsions were prepared carefully following two different procedures - unheated and heated mixing. The former to emulate cold start and “bakery” driving use, the latter to reproduce what happens after the engine heats in normal conditions. Thus, four contamination recipes: ethanol and water-ethanol, unheated and heated mixing prior the test were compared to the fresh oil. Confirming literature outcomes from previous works, the contaminated oils showed lower friction than the baseline oil. Firstly, when tested at 50°C, the presence of both contaminants reduced ring/liner friction by about 15%. However, at 130°C, ethanol effect was mitigated, probably due to its rapid evaporation. In contrast, water-ethanol containing oil kept a level of 8% in friction reduction even at high temperature, when compared to its fresh version. The wear of cylinder liner and piston ring were not significantly affected by the dilutions, but somehow surprisingly liner wear was slight lower for the tests with contaminated oils.
Wheel end bearing is one of the critical components of the vehicle as it directly faces the road loads for harsh operating environment. Bearing being a precisely manufactured component and rotating at high speed, utmost care is required while assembling as well as during operation. In operating condition wheel end is directly exposed to outside environment making it prone to entry of contamination. This contamination if not prevented from entering into wheel end through proper sealing it would cause lubricant contamination and consequently bearing failure. Bearing replacement and overall wheel end service is time consuming activity reducing the turn out time of the vehicle. In wheel ends, one side is sealed with the help of seal while the other side is protected by cap and gasket. This cap-gasket interface is very critical from sealing perspective and utmost importance needs to be taken while designing the same. This paper focuses on the various aspects of design to be considered while designing gasket and caps for the sealing of wheel hubs. Additionally CAE analysis methodology is adopted to virtually find the effects of different gasket and hub cap parameters on sealing. Hub cap and gasket together forms a wheel end sealing. In wheel ends, a gasket is mounted on wheel hub face and cap is bolted on to it. When the bolt is tightened, tightening force gets transferred from hub cap to gasket and generates compression. This compression makes the joint leak proof. Different design parameters like cap thickness, bolt preload are studied to find out the performance of the gasket joint. Pressure compression curve of gasket is used for studying the behavior of gasket at different cap thickness. For virtual analysis sealing performance of gasket and cap is evaluated by doing nonlinear analysis of gasket joint. ANSYS workbench is used as a finite element analysis tool to simulate wheel hub gasket performance. Some additional steps are used in this analysis besides other conventional nonlinear analysis in ANSYS. CAE results are then finally evaluated by physical fitment of parts on vehicles and measurement is done accordingly. Footprints of gasket\hub cap is taken on physical vehicle and compared with virtual footprints. Also contamination studied on periodic intervals between new and old designs to analyze the results
Debris are progressively generated just after wear occurred by the interaction of various mechanical elements inside the engines, steering gear boxes, transmissions, differentials, etc. Besides, debris could interfere with the normal operation of such components generating even more damage in other parts due to three-body abrasion. Hence, dynamic seals are susceptible to interact with very fine debris accumulated in the working lubes. Recently, owing to many test advantages, the micro-scale abrasion test has been extensively used to reproduce three-body abrasion in hard materials, coatings, polymers, etc., however, it has not been before employed for the wear assessment of elastomeric materials. This paper presents an adaptation of the micro-scale test method to study three-body abrasive behavior of an elastomeric dynamic seal (samples extracted from an automotive commercial Acrylonitrile-butadiene NBR rotary seal) under lubricated conditions. This work looks generate three-body abrasion on the NBR material, proposing a range of test conditions (Load, sliding speed, sliding distance and abrasive concentration) and quantify the volume loss. Engine lubricant contaminated with SiC micro-particles was used toward replicating the actual seal lip-rotary shaft interface condition. According to SEM images from the wear scars, the wear mechanisms were polishing (two-body abrasion), three-body abrasion, and a mixture of them. Nevertheless, three-body abrasion was just obtained under specific conditions. Finally, the particular wear pattern of three-body abrasion of elastomers was achieved. Even more, the method should be potentially used to test any elastomeric material in order to characterize the three-body abrasion resistance.
The economics of operating internal combustion engines in cars, buses and other automotive equipment is heavily affected by friction and wear losses caused by abrasive contaminants. As such, dust is a universal pollutant of lubricating oils. Road dust consists of depositions from vehicular and industrial exhausts, tire and brake wear, dust from paved roads or potholes, and from construction sites. Present research investigates the influence of dust powder of size 5 μm-100 μm as contaminant in SAE 20W-40 lubricant on the relative motion of a plane surface over the other having circular surface in contact. A pin-on-disk setup as per ASTM G99 has been used to conduct the experiments, firstly at increasing rpm keeping constant load of 118 N, and secondly by increasing loads, keeping rpm constant at 1000. The contaminated lubricant has been used to study its influence on friction and wear rate at the interface of pin of 12 mm diameter and disk at track diameter of 98 mm. Based on the experiments at constant load, the coefficient of friction decreased with increase in rpm and the wear rate first increased and then decreased. At constant rpm, the coefficient of friction as well as wear rate first increased then decreased as the load enhanced. Both friction and wear rate increased in the final stages of the experiment. Good performance of the lubricant can be attributed to the third body effect shown by fine dust particles.
This procedure will be generally applicable to three classes of hydraulic components as listed below:
The performance of lubricant oils and, consequently, the performance of the engine and its useful life are significantly affected by the degree of contamination with fuel such as gasoline and ethanol. The determination of such contamination is of utmost importance both during the development of the engine components and for field verification. The official existing method is ASTM D3525, which is based on gas chromatography and requires significant investments in equipment and facilities, without mentioning the need for qualified personnel for the operation. Thus, the development of a reliable, simple, rapid and low cost method is required. This work was intended to prove the efficacy of the gravimetric method for the determination of fuel in lubricant oil. Such verification was conducted by comparing the results obtained through gravimetric and chromatographic methods. In this regard, both results were similar between each other being that the gravimetric method results were closer to the theoretical ones than those of the chromatographic method.
Major fluid-lubricated aircraft components can be damaged or severely degraded if the lubricating properties of the fluid have been prematurely degraded via oxidation during periods of heavy or severe usage. In addition, fairly rapid contamination of the lubricant via water, soot, or fuel ingress can occur due seal failures, environmental conditions, and/or maintenance. Prolonged aircraft use under any of these degraded conditions can also lead to symptoms of component wear-out and the generation of increasing levels of ferrous or non-ferrous debris in the oil. Polymeric Bead Matrix Technology can independently track and trend all of these wear conditions in real time, thus providing a prognostics-like capability for unscheduled oil degradation events. The patented PBM technology has been in use for many years in the mining industry where it has been used to monitor large crankcases in diesel and gasoline engines, gear boxes and hydraulic systems. A key benefit of the PBM system is that it is calibration free, and its on-board use has the potential to make all off-line fluid sampling and Infrared Spectroscopy "on-Condition".
The overall performance of direct injection (DI) engines is strictly correlated to the fuel liquid spray evolution into the cylinder volume. More in detail, spray behavior can drastically affect mixture formation, combustion efficiency, cycle to cycle engine variability, soot amount, and lubricant contamination. For this reason, in DI engine an accurate numerical reproduction of the spray behavior is mandatory. In order to improve the spray simulation accuracy, authors defined a new atomization model based on experimental evidences about ligament and droplet formations from a turbulent liquid jet surface. The proposed atomization approach was based on the assumption that the droplet stripping in a turbulent liquid jet is mainly linked to ligament formations. Reynolds-averaged Navier Stokes (RANS) simulation method was adopted for the continuum phase while the liquid discrete phase is managed by Lagrangian approach. To simulate the complete evolution of the injected droplets, the proposed atomization model was coupled to a secondary breakup model based on Kelvin-Helmholtz (KH) instability equations. The KH secondary breakup model was tuned in order to provide non-dimensional breakup time fitting experimental evidences all over the range of droplet Weber numbers. To test the new atomization model, a multi-hole high pressure gasoline direct injector was considered. In the present paper, simulation results are compared to experimental ones in terms of overall spray evolution along the injection period, local droplet diameter, and droplet velocity distribution.
The purpose of this SAE Information Report is to provide information on refrigerant issues of concern to the mobile air-conditioning industry.
A debris-contaminated lubrication environment is inherent in many equipment applications and requires mechanical components that, as much as possible, are resistant to the potential detrimental effects of debris particles. In addition, lubricants are formulated with chemistry targeted to prevent wear in mechanical systems, and standard tests are used to evaluate the lubricant's ability to impact this failure mechanism. However, many researchers and lubricant specialists often overlook potential relationships between the various failure modes and the engineering solutions that are created to overcome them. The role played by lubricant additives and debris-contaminated lubricants in the failure mechanisms of bearings is just one example requiring closer consideration. Performance evaluation results of tapered roller bearings in the areas of material fatigue and wear in connection with lubricant contamination and lubricant chemistry will be discussed. Several conclusions are drawn in regard to variations observed in these evaluation tests.
This method describes a procedure for the sizing and counting of particulate contamination in liquid samples by membrane filtration. The procedure will allow measurement of particulate contamination five micrometres or greater in size with a maximum variation of ±20% in results over an average of two runs. This procedure can be used for all samples where the membrane filter is compatible with the sample liquid and rinse liquid. Section II of this procedure may be used to count any sample on a gridded membrane where particles are evenly distributed. This procedure is an alternative to counting with an automatic particle counter although results by each method from identical samples might not be equivalent due to individual idiosyncrasies in each technique.
A series of engine dynamometer tests was carried out with 100% ethyl ester of soya oil as fuel and six different diesel engine lubricants. In each case the lubricant became contaminated by unburnt fuel during the tests with measured dilution rates of up to 0.2% of the fuel throughput. The lubricant/fuel mixture eventually underwent degradation to such an extent that phase separation occurred. The tests were terminated when the lubricant lost all dispersancy, as evaluated by a blotter-spot teat. Used oil analysis revealed that rapid oxidation of some of the fatty acid ester components of the fuel diluent had occurred in the later stages of the tests. At the high levels of fuel dilution recorded in these tests there was little difference between the performances of the six lubricants, despite their differing performance categories. It is therefore concluded that conventional performance categories cannot be used to define the grade of lubricant necessary for use with 100% vegetable oil ester fuels.
This test describes a self-checking procedure for the determination of particulate contaminant five microns or greater in size in air by the particle count method. A maximum variation of two to one (±33% of the average of two runs) in results should be expected for replicate counts on the same sample, providing that the procedure is followed closely and the precautions presented regarding check samples and self-checking aspects are observed.
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