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The lubricating oil is a non‐renewable source of energy and its useful life is limited due to deterioration during its usage. It is desirable to maximize its use to conserve this scarce resource. At present, continuation or change of the engine oil is decided, based on the manufacturer's recommendation and experience. The suggested engine oil change period is conservative and results in non‐efficient usage of engine oil. This practice needs refinement to include all possible properties/attributes of engine oil and use of appropriate procedure to assess its realistic performance. The paper aims to analyze the procedure.

Oil reliability polygraph is used to analyze the engine oil performance during operation. Reliability analysis of the engine oil is carried out by comparing the area of oil reliability polygraph at a given operation time with the area for the fresh engine oil. The suggested procedure is illustrated by means of an example.

Physical and chemical properties responsible for performance degradation of the engine oil are considered as engine oil reliability attributes. The value of these attributes from time to time, obtained by analyzing samples drawn from the system, is analyzed through oil reliability polygraph. In this approach, the engine oil reliability attributes at a given operation time are represented in terms of reliability value to obtain the “oil reliability polygraph”.

The suggested procedure will be helpful for maintenance personnel in taking planned maintenance action.

The use of “preservative” motor oils was a development of the recent war. The need for rust prevention has been recognised for many years, but only in the last decade were efforts concentrated to prevent rusting in an efficient and scientific way. Engine oil specifications have changed during the past ten years to comply with the higher requirements resulting from changes in engine design. The preservative type motor oils, which were developed during the same period, must meet these more rigid specifications and also act as corrosion preventives. Engine Preservative Oils serve the double function of preservation and lubrication. As a preservative, the oil should fully protect steel or any other metal which may be found in an engine assembly, whether the engine is stored or in operation. As a lubricant, it must comply with the exacting requirements set for automotive and aircraft engines. Because of the complexity of aircraft motors, specifications are generally more severe for aircraft than automotive engine preservatives. Illustrations of these specifications are presented for automotive oils, and only reference will be made to aircraft oils. Film forming engine preservatives, as required by the U.S. Bureau of Ships, will not be discussed because of lack of oily constituents.

Traditionally the development process has been used to optimise engine lubrication systems with a lot of hardware testing. This can lead to an expensive and time consuming process which can have major influences on the engine design. To complement engine development, design and analysis principles have been developed for further optimisation and understanding of the lubrication system. To demonstrate this a case study is used illustrating good use of analysis tools, offering clear ways towards system optimisation. In addition, while engine designers have been improving their techniques, new components and oil formulations have helped push the boundaries of the lubrication system, giving better wear and friction characteristics and also increasing oil life.

Nanoparticles have been studied as additives to lubrication oils for reducing friction and wear. The purpose of this paper is to investigate the effect of nanofluid on engine oil and friction reduction in a real engine.

The nanoparticles were prepared using a high‐temperature arc in a vacuum chamber to vaporize the Ti metal, and then condensed into a dispersant to form the TiO₂ nanofluid, which was used as lubricant additive. Experiments were performed in both real engine running and test rig.

It was found that the engine oil with nanofluid additive with an ethylene glycol dispersant of nanoparticles, had gelled after 10‐h of engine running. The problem of oil gelation (jelly‐like) was solved by replacing the dispersant with paraffin oil. The engine oil with TiO₂ nanoparticle additive exhibited lower friction force as compared to the original oil. The experiment showed that a smaller particle size exhibits better friction reduction with particle size ranging from 59 to 220 nm.

The paper is restricted to findings based on the dispersed nanoparticles in fluid as additive for engine lubrication oil.

The test results are useful for the application of nanofluid additive for engine oil.

Most previous researches in this field were executed on tribotester, rather than the actual engine. This paper describes experimental methods and equipment designed to investigate the application of TiO₂ nanofluid as lubricant additive in internal combustion engine.

The purpose of this paper is to present the results of research into using an additive to SAE 15W/40 engine oil during operation and its influence on lubricating properties (normalised tests) on weld point Pz, non-seizure load Pn, load wear index Ih and on seizure load Pt. The friction pair consisted of a group of four balls and the tested lubricant. Moreover, the author tested the influence of an additive to engine oil (non-normalised tests) on tribological properties, including friction force, wear and the temperature of friction area for the C45 steel/210Cr12 steel friction joint. She also determined the influence of an additive to engine oil on the formation of the operating surface layer. The research results helped to build the model of the boundary layer that was formed as a result of adding an additive to engine oil.

The lubricant properties of engine oil and engine oil to which an additive was added during operation were determined according to PN-76/C-04147. The following are the indexes of lubricant properties: weld point Pz, load wear index Ih, non-seizure load Pn, seizure load and average scar diameter. The Pz, Pn and Ih indexes were determined at abruptly increasing load to the moment of welding of the friction pair. The Pt index was determined at the increasing load of the friction pair from 0 to 800 daN at the speed of 408.8 N/s. The tests of tribological properties (friction force, wear and the temperature of friction area) were conducted for the C45/210 Cr12 friction pair in the presence of a lubricant and a lubricant with an additive.

The modification of SAE 15W/40 engine oil with the additive added during operation resulted in improved indexes of lubricant properties Pz, Pn, Ih and Pt and average scar diameter. The boundary layer for the modified oil breaks after a longer time and at lesser friction force. The modification of the engine oil reduced the wear of the friction pair. After the friction process, element composition in the surface layer of the wear trace and its distribution were determined in relation to applied lubricants. A significant amount of sulphur, phosphorus and oxygen, as well as an insignificant amount of copper, was observed in the wear trace after the friction process in the presence of the lubricant medium. The distribution of elements in the wear trace when the engine oil with the additive was used is steady in the wear trace and outside it. Some sulphur, phosphorus and chlorine were found in the wear trace.

The results of tests on tribological properties (non-normalised tests) confirmed the positive affect of the additive to engine oil on lubricant properties (normalised tests). The modification of the engine oil caused reduced friction force and the reduced wear of the friction pair. The reduction of friction force and wear was the result of the formation of the surface of a greater amplitude density of unevenness tops in the friction process. Moreover, the operating surface layer, created in the friction process when the additive was added to the engine oil, had greater load participation at 50 per cent C. This operational surface layer improved tribological properties, i.e. it reduced value of friction force and wear. The test results were used to build a model of the boundary layer created as a result of the additive added to engine oil.

The steam engine was the first practical means of producing mechanical power from the heat of combustion of a fuel, and its introduction was a vital factor in the progress of the Industrial Revolution. For many years the development of the steam reciprocating engine continued apace, but in the early years of the present century introduction of the steam turbine and internal combustion engine made available alternative methods of power production. From then on interest in the steam reciprocating engine tended to slacken and, although it has shown a number of notable improvements, far more spectacular advances have been made in other power units.

The more frequently an engine oil is changed, the more the overhaul life of the engine is extended but with an increase in the cost both of the oil and of the oil drain services. If engine oil is changed less frequently the associated costs will decrease. In order to find the optimum drain interval, it is necessary to establish the relationship between the cost of the oil and oil drain services and the cost of more frequent overhauls. Presents an investigation into the degradation of a proprietary lubricant marketed in Turkey, and the wear rate of a petrol engine driven in urban traffic. Lubricant samples were examined approximately every 2,000km for deterioration of the lubricant and evidence of wear of the engine components. From the experimental results, determines the optimum oil drain period of the engine.

A series of articles dealing, in as simple a way as possible, with the basic facts of lubrication, lubricants, their selection and prescription, specification, application, and testing. This series is primarily intended for students, engineering personnel who may be unfamiliar with certain aspects and others who, one way or another, are interested in this important subject.

This paper aims to compare the conditions of in-service oils from diesel and gasoline engines, with focus on nitration.

Oil conditions of seven engine oil samples from five diesel-fueled vehicles and nine oil samples from eight gasoline-fueled vehicles with total mileage ranging from 13,600 to 30,000 km were determined via Fourier-transform infrared spectroscopy as well as neutralization number (NN) and total base number titration.

Chemical deterioration was characterized by significant differences in oxidation, nitration, NN increase and residual aminic antioxidant contents.

Submitted in connection with the Special Issue, “Young Tribologists – Insights into the work of the new generation”.

Uncovering differences in the oil degradation of oils from gasoline and diesel engines enables improved condition-based maintenance strategies and the prediction of oil condition dependent tribological performance.

The purpose of this paper is to determine whether the altitude at which construction equipment operates affects or contributes to increased engine wear.

The study includes the evaluation of two John Deere PowerTech Plus 6,068 Tier 3 diesel engines, the utilization of OSA3 oil analysis laboratory equipment to analyze oil samples, the employment of standard sampling scope and methods, and the analysis of key Engine Control Unit (ECU) data points (machine utilization, Diagnostic Trouble Codes (DTCs) and engine sensor data).

At 250 h of engine oil use, the engine operating at 3,657 meters above sea level (MASL) had considerably more wear than the engine operating at 416 MASL. The leading and earliest indicator of engine wear was a high level of iron particles in the engine oil, reaching abnormal levels at 218 h. The following engine oil contaminants were more prevalent in the engine operating at the higher altitude: potassium, glycol, water and soot. Furthermore, the engine operating at higher altitude also presented abnormal and critical levels of oil viscosity, Total Base Number and oxidation. When comparing the oil sample analysis with the engine ECU data, it was determined that engine idling is a contributor for soot accumulation in the engine operating at the higher altitude. The most prevalent DTCs were water in fuel, extreme low coolant levels and extreme high exhaust manifold temperature. The ECU operating data demonstrated that the higher altitude environment caused the engine to miss-fire and rail pressure was irregular.

Many of the mining operations and construction projects are accomplished at mid to high altitudes. This research provides a comparison of how construction equipment engines are affected by this type of environment (i.e. higher altitudes, cooler temperatures and lower atmospheric pressure). Consequently, service engineers can implement maintenance strategies to minimize internal engine wear for equipment operating at higher altitudes.

The main contribution of this paper will help construction equipment end-users, maintenance engineers and manufacturers to implement mitigation strategies to improve engine durability for countries with operating conditions similar to those described in this research.