Martin Novák

Bio: Martin Novák is an academic researcher. The author has contributed to research in topics: Lubricant & Motor oil. The author has co-authored 1 publications.

Study of the Effect of Physicochemical Degradation and Contamination of Motor Oils on Their Lubricity

Abstract: Internal combustion engine lubrication is essential for unwanted energy and material losses. As part of the experimental work, the lubricity of both new and worn motor oils of Society of Automotive Engineers (SAE) 15W-40 and SAE 10W-40 with different American Petroleum Institute (API) performance classifications, which were taken from various motor trains during maintenance or oil change, was assessed. A total of sixteen lubricant samples were evaluated. Lubricity, i.e., the load capacity of the lubricating film, was evaluated on the basis of the Reichert test. Viscosity, as one of the most important parameters of lubricants, was evaluated by the Stabinger Viscometer. Chemical degradation of motor oils (oxidation, nitration, sulfation), contamination of oils with fuel, soot, water, and loss of antioxidant zinc dialkyldithiophosphate (ZDDP) were monitored by Fourier-transform infrared (FTIR) spectroscopy. Of the fresh motor oils, OMV 10W-40 API SL/CF motor oil had the best lubricity. URANIA LD 15W-40 API CI-4 and M7ADS V 15W-40 API CI-4 CH-4/SL oils showed similar lubricity. M7ADS III 15W-40 API CF-4/SG motor oil showed the highest wear of wear surface, i.e., the lowest lubricity, of the tested new motor oils. Correlation analysis of the experimental data confirmed that the fuel content penetrated the motor oils significantly negatively correlates with the viscosity (R = −0.87). The low water contamination in motor oil does not cause a significant negative effect on lubricity. A significant correlation between the oxidation, nitration, and sulfation products of chemical degradation of the tested oils was confirmed (R ≥ 0.90). These degradation products improve lubricity due to their polarity, i.e., they have caused better lubricity of worn oils compared to new motor oils. Even the depletion of the antioxidant ZDDP did not affect the reduction in lubricity and anti-abrasion properties of chemically degraded motor oils. The experimental results of testing of worn motor oils taken from motor trains showed that current motor oils have excellent lubricity, which they maintain throughout their life.

Study of the Relationship between the Level of Lubricating Oil Contamination with Distillation Fuel and the Risk of Explosion in the Crankcase of a Marine Trunk Type Engine

Abstract: Fuel contamination of engine lubricating oil has been previously determined to arise from two independent phenomena: the effect on oil flash point, and the effect of changing lubrication conditions on tribological pairs. This paper combines these effects and holistically analyzes the consequences of fuel in the lubricating oil of a trunk piston engine on the risk of crankcase explosion. The author hypothesized that diesel fuel as an oil contaminant increases the risk of an explosion in the crankcase of an engine due to the independent interaction of two factors: (1) changes in the oil’s combustible properties, and (2) deterioration of the lubrication conditions of the engine’s tribological nodes, such as main bearings, piston pins, or crank bearings. An experiment was performed to evaluate the rheological, ignition, and lubrication properties of two oils (SAE 30 and SAE 40) commonly used for the recirculation lubrication of marine trunk piston engines for different levels of diesel contamination. The hypothesis was partially confirmed, and the results show that contamination of the lubricating oil with diesel fuel in an amount of no more than 10% does not significantly affect the risk of explosion in the crankcase. However, diesel concentrations above 10% call for corrective action because the viscosity index, lubricity, coefficient of friction and oil film resistance change significantly. Deterioration of the tribological conditions of the engine bearings, as seen in the change in viscosity, viscosity index, and lubricity of the oil, causes an increase in bearing temperature and the possibility of hot spots leading to crankcase explosion.

Implementation of Nitration Processes in Artificial Ageing for Closer-to-Reality Simulation of Engine Oil Degradation

Abstract: During their service, engine oils suffer from various influencing parameters such as thermo-oxidative stress and nitration, hence, the accumulation of degradation products and the entry of contaminants. Accordingly, ICEs need to be able to operate satisfactorily, especially with a degraded lubricant, making it highly recommendable to use such oils for component testing in ICE development. Thus, a new nitrative thermo-oxidative ageing method is presented for closer-to-reality simulation of engine oil alteration with the intention to provide reproducibly aged oils for subsequent bench testing. With this method, a target used oil from field application was replicated and the comparability of oil condition in the lab vs. field regarding oxidation, nitration, additive depletion, and acidification amongst others was verified by conventional and advanced analyses. Special focus was laid on the identification of nitration products, proving them to be predominantly oxidized aromatic species or organophosphates. The presented method gives valuable benefit for the closer-to-reality ageing of engine oils in reasonable time frames with moderate costs and, hence, for the provision of test oils for ICE bench testing enabling rapid engine component assessment.

Design of a tribotechnical diagnostics model for determining the technical condition of an internal combustion engine during its life cycle

Abstract: The paper proposes a model of tribotechnical diagnostics, which allows us to determine the technical condition of an internal combustion engine within its life cycle and then take measures, including its decommissioning due to excessive wear of major components. The paper also focuses on tribodiagnostic methods that are suitable for assessing the technical condition of internal combustion engines used in various means of transport (automobiles, railway locomotives powered by internal combustion engines, aircraft powered by reciprocating internal combustion engines, special and garden equipment). An internal combustion engine from agricultural equipment was selected for the experiment and monitored throughout its life cycle. The paper describes in detail the appropriate methods used for the proposed tribotechnical diagnostics model, including the results from the measurements by these methods. The said methods were then evaluated and mutually compared. The following advanced instrumental analytical methods were used to evaluate the collected engine oil samples: atomic emission spectrometry (AES), ferrography, automatic laser counter and LNF particle classifier, FTIR infrared spectrometry. The result of the work (paper) is the design of a tribotechnical diagnostics model for determining the technical condition of an internal combustion engine during its life cycle and the determination of limit values for assessing the technical condition of a Honda GCV 165 internal combustion engine. The results are based on individual measurements.

Prediction of RUL of Lubricating Oil Based on Information Entropy and SVM

Abstract: This paper studies the remaining useful life (RUL) of lubricating oil based on condition monitoring (CM). Firstly, the element composition and content of the lubricating oil in use were quantitatively analyzed by atomic emission spectrometry (AES). Considering the large variety of oil data obtained through AES, the accuracy and efficiency of the RUL prediction model may be reduced. To solve this problem, a comprehensive parameter selection method based on information entropy, correlation analysis, and lubricant deterioration analysis is proposed to screen oil data. Then, based on a support vector machine (SVM), the RUL prediction model of lubricant was established. By comparing the experimental results with the output data of the prediction model, it is shown that the accuracy and efficiency of the SVM prediction model established after parameter screening have been significantly improved.

Atmospheric pressure matrix‐assisted laser desorption/ionization mass spectrometry of engine oil additive components

Abstract: Rationale The efficiency of lubricants strongly depends on the content of functional additives. In order to assess the chemical and structural changes taking place in the lubricating oil and its additives during operation, it is essential to develop a method for simple and prompt analysis. Methods Two single additives as well as a fully formulated engine oil were analysed using an atmospheric pressure matrix‐assisted laser desorption/ionization (AP‐MALDI) source coupled to a linear trap quadrupole Orbitrap XL hybrid tandem mass spectrometer and compared with results obtained by means of electrospray ionization (ESI) including additional low‐energy collision‐induced dissociation (LE‐CID). The identification of additives directly from technical surfaces was simulated by using steel substrates as AP‐MALDI targets with varying roughness. Results After assessment and selection of the most suited AP‐MALDI matrix it was found that pure additives such as calcium sulfonate and zinc dialkyldithiophosphates (ZDDPs) could well be identified with abundant signal intensity based on their elemental composition. Molecular identification was corroborated by LE‐CID in ESI mode. Additionally, additives present in the fully formulated commercial oil such as ZDDPs and salicylates could be reliably identified based on the elemental composition of the deprotonated molecules by means of the Orbitrap unit on different substrates including steel surfaces with high roughness. Conclusions AP‐MALDI is an efficient technique for determination of lubricant additives directly from commercial oil blends. Identification of additive components was also achieved on steel surfaces with high roughness as applied in tribological systems and thus it is expected that it will be possible to assess additive degradation in real applications, enabling more effective and timely maintenance measures.