15W-40 Engine Oil Research Articles

Engine Oils in the Field: A Comprehensive Chemical Assessment of Engine Oil Degradation in a Passenger Car

For the understanding of oil degradation in a combustion engine, in particular zinc dialkyl dithiophosphate (ZDDP) deterioration and its impact on wear expressed as iron content, a field test with a passenger car was carried out, which covered a distance of 19,800 km and represented an entire oil change interval. Condition monitoring of the SAE 5W-30 engine oil used in the turbocharged petrol engine combined the use of conventional and advanced analytical methods. The conventional data collected from the used oils revealed the progress of additives (antioxidants, base reserve, ZDDP), oil degradation products (oxidation, nitration, sulfation, acids), and contaminations (water, soot, wear, fuel dilution). High-resolution mass spectrometry was included to identify ZDDP additive compounds and their fate during the field test as well as their correlation with wear formation. Dialkyl dithiophosphates as the main ZDDP compounds were rapidly degraded and no longer detected after 6000 km. Dialkyl thiophosphate as intermediate ZDDP degradation product was formed and largely depleted within the first 6000 km. Dialkyl phosphates, phosphoric acid, and sulfuric acid as organic and inorganic ZDDP degradation products were generated early and reached high levels at the end of the field test. The presence of intact ZDDP and its degradation products, notably phosphoric and sulfuric acid, correlated with the oil’s iron content. Wear largely remained at low level as long as intact ZDDP was available for tribofilm formation. The lack of ZDDP along with the formation of inorganic acids from ZDDP resulted in an increase in the wear rate by a factor of four.

Rheological and Thermal Properties of Lubricating Oil Enhanced by the Effect of CuO and TiO2 Nano-Additives

The specifications of lubricating oil are fundamentally the final product of materials that have been added for producing the desired properties. In this research, spherical nanoparticles copper oxide (CuO) and titanium oxides (TiO2) are added to SAE 15W40 engine oil to study the thermal conductivity, stability, viscosity of nano-lubricants, which are prepared at different concentrations of 0.1%, 0.2%, 0.5%, and 1% by weight, and also their pour point, and flash point as five quality parameters. The obtained results show that CuO nanoparticles in all cases, give the best functionality and effect on engine oil with respect to TiO2. With 0.1 wt. % concentration, the thermal conductivity of CuO/oil and TiO2/oil increased by 7.27% and 4.54%, respectively. In the same time, the flash point of them increased by 12.62% and 9.3%, respectively in comparison with parent oil.

Monitoring of Engine Lubrication using Acoustic Emission Technology

This research presents the application of Acoustic Emission (AE) sensor to explore the feasibility of an AE signal in the process of monitoring the engine oil viscosity on different condition of mileage during the engine operation. The viscosity experiment was performed in a prior stage of the experiment using four samples of SAE 5W-30 engine oil with the different condition of mileage. On the next occasion, the AE signal was acquired on three cylinders of a four-stroke gasoline engine with a cooling water system which operates using the previous lubricant sample. In this experiment, the AE sensor was bonded on the outside of the engine block and located at the oil filter and oil sump location. It was found that the AE energy value is capable of determining the variant of the engine oil viscosity. The results from this project show that via AE technology proved to be feasible for the development of a real-time lubricant condition monitoring which was believed to be a new technology in the automotive industry.

Experimental investigation of hybrid nano-lubricant for rheological and thermal engineering applications

Nowadays, various types of engine oils are widely used in lubricating and cooling internal combustion engines. In this study, the behavior of MWCNTs–SiO2 (30–70)/10W40 hybrid nanofluid as part of a new generation of engine oil is investigated experimentally. A mixture of SiO2, with 20–30 nm particle diameter, and MWCNT, with 3–5 nm inner and 5–15 nm outer nanoparticle diameter was dispersed into a base fluid of 10W40 engine oil. Then, the viscosity of the product was measured at nanofluid concentrations and temperatures, respectively, ranging from 0.05 to 1% and 5 to 55 °C, for different values of shear rate. Also, a sensitivity analysis to the solid volume fraction was performed at different temperatures. The results show that the behavior of the samples is well fitted with the pseudo-plastic Ostwald de Waele non-Newtonian model. The viscosity of the produced hybrid nano-lubricant is found to be 35% greater than that of pure engine oil. Because of the significant deviation between the measured viscosity and the values predicted by existing classical viscosity models, a new regression model is obtained. The R2 and adj. R2 for the model are computed as 0.988 and 0.977, respectively, signifying strong predictability with ± 3% margin of deviation.

Improve the thermal conductivity of 10w40-engine oil at various temperature by addition of Al2O3/Fe2O3 nanoparticles

Oils are used as coolants and lubricants in different industrial systems with the aim of reducing friction between parts and their abrasion. The objective of the present study was to investigate the effect of addition of Al2O3-Fe2O3 Nano powder hybrid on the thermal properties of 10w40 engine oil. In this study, the effect of nanoparticle concentration at different mass fractions (0, 0.25, 0.5, 1, 2, and 4) was examined. Experiments were conducted within a temperature range of 25–65 °C. The nano-lubricant was prepared using the two-stage method. An ultrasonic probe was used for 45 min to uniformly distribute the nanoparticles in the base fluid. The thermal conductivity coefficient of the hybrid nanofluid was measured using the KD2-Pro thermal analyzer, the results of which indicated that even the smallest mass concentration improved the thermal properties of the nano-lubricant. Accordingly, the largest improvement occurred at a mass fraction of 4%, i.e. 33% of the base oil. In order to calculate the thermal conductivity of the nano-lubricant using the temperature and mass fractions of the particles, the curve fitting method was applied to the experimental data to find a highly accurate experimental relation in SigmaPlot V12.

Lubricating behavior of Submicrometer carbon spheres as lubricant additives

The purpose of this paper is to evaluate carbon spheres as a green lubricant additive in 5W30 engine oil to reduce friction and wear. Carbon spheres with a diameter of ∼400 nm are synthesized from glucose by using a hydrothermal process. Lubrication is studied using a ball-on-disk tribometer by measuring the friction coefficient and wear in the boundary lubrication regimes. The worn surfaces were analyzed by Raman spectroscopy. Carbon spheres are found to be stably dispersed at 0.5 wt% concentration in base oil. The experiments revealed that carbon spheres are effective in reducing both friction and wear when lubricating by using base oil. Raman results show that the enhanced tribological performance is owing to a carbon-rich boundary film, the formation of which is attributed to the deposit of carbon particles during the sliding process.

Using artificial neural network for investigating of concurrent effects of multi-walled carbon nanotubes and alumina nanoparticles on the viscosity of 10W-40 engine oil

The present study used artificial neural networks (ANNs) and experimental data to model the viscosity of the MWCNT (50%)–Al2O3 (50%)/10W40 hybrid nanofluid at different temperatures from 5 to 55 °C and for nanoparticle volume fractions of 0.05% to 1%. An ANN and a new correlation as function of solid volume fraction, temperature and shear rate. The multidimensional MLP-ANN was employed and investigated as the learning algorithm. The R-squared values for the proposed correlation and ANN were obtained to be 0.9973 and 0.9944, respectively. In order to analyze the importance of each term of correlation, p-value of parameters is determined. Also one factor and two factor analysis of viscosity are presented in this study. According to one and two factor analysis results, temperature changes has the highest effect on viscosity. Shear rate and solid volume fraction effects on viscosity are in next level of importance.

Effect of temperature on wear and tribofilm formation in highly loaded DLC-steel line contacts

Abstract In the present study the tribological properties of DLC coatings are analysed by performing Stribeck experiments with a block on ring (BoR) configuration, developed for a rotational tribometer, under different temperatures operated with a conventional 5W30 engine oil. Both, block and ring are made of steel and surface hardened, whereby a-C:H coating with CrN adhesion and CrC gradient layer is deposited on the latter. Results reveal, that the amount of formed Zinc dialkyldithiophosphate (ZDDP) tribofilms can be linked directly to changes of wear volume and boundary friction coefficient (COF). Furthermore, wear and tribofilms can trigger topological surface adaptations, leading to a different frictional behaviour in the fluid lubrication regime as well. Optical, energy dispersive X-ray (EDX) and thermoelastohydrodynamic (TEHD) numerical analysis were carried out in order to gain a holistic understanding of phenomena taking place in DLC/steel tribosystems. Findings indicate, that anticipated positive effects of DLC coatings are partly suppressed due to the onset of these films under conditions relevant in automotive engines.

A study on rheological characteristics of hybrid nano-lubricants containing MWCNT-TiO2 nanoparticles

In the present study, dynamic viscosity of four nano-lubricant with different combinations of carbon nanotube (CNTs) and Titania (TiO2) nanoparticles (10%–90% and 55%–45%) in 10w40 engine oil has been investigated. These nanofluids were prepared in solid volume fraction range of 0.25%–1% and have been tested at temperature ranging from 15°C to 55°C. Another investigated variable was the fluid shear rate that has been taken into consideration in order to study the rheological behavior of nanofluids. Increase and decrease of the viscosity are the effects of particle volume fraction and temperature on the nanofluid, respectively. In all types of nanofluids, it is occurred about 80% reduction in the viscosity with increasing of the temperature, of which the used nanoparticle has no significant effect on this value. Moreover, the nanofluids containing MWCNTs at the solid volume fraction of 0.75%, is faced with an increase of 100% in the viscosity. The experimental results also indicate that increasing in the percentage of carbon nanotube in the nanofluid has a considerable effect on the non-Newtonian behavior of the fluid and this increase enhances the shear-thinning behavior of suspensions.

Investigation on the Effect of Tio2 Nanoparticle Additives on the Properties of 10w-40 Engine Oil

Investigation on the Effect of Tio2 Nanoparticle Additives on the Properties of 10w-40 Engine Oil

Characterization of Al2O3-SAE 15W40 engine oil nanolubricant and performance evaluation in 4-stroke diesel engine

This work aims to characterize Al2O3-SAE 15W40 engine oil nanolubricant and its performance evaluation in 4-stroke diesel engine. Field emission scanning electron microscope (FESEM) images of nanoparticle reveal the spherical morphology of nanoparticle and Fourier transform infrared spectroscopic results show chemical stability of nanolubricants. Dynamic light scattering test display the presence of mild agglomeration of particles in nanolubricants, further FESEM images of dispersed nanoparticles re-confirms it. Density and viscosity of nanolubricants are measured with varying particle volume fraction and temperature. The overall performance of nanolubricant is tested on a 4-stroke diesel engine. The nanolubricant with 0.3% volume fraction of Al2O3 nanoparticles shows less frictional power loss and hence higher brake thermal efficiency as compared to other nanolubricants.

A novel experimental investigation on the effect of nanoparticles composition on the rheological behavior of nano-hybrids

In this study, The rheological behavior of nanofluids resulting from combination of MWCNT and Al2O3 nanoparticles in 10W40 engine oil has been investigated experimentally. The studied range of temperature was 15–55°C from different hybrid and single nanofluids. Also, MWCNT/10W40 in three volume fractions of 0.75%–0.1%, Al2O3/10W40 in volume fractions of 0.25–1%, and mixed nanofluid of MWCNT and Al2O3 (40–60%) in volume fractions of 0.25, 0.75, and 1% were prepared. Shear rate of studied fluids was from 100 to 900rpm. Then, experimental data were modeled by artificial neural networks. This modeling was conducted with high accuracy, which reveals that neural network is a powerful tool in modeling experimental data. The results show that all nanofluids have a similar behavior towards the increase of temperature. Increase of volume fractions of nanoparticles is also accompanied with increase of dynamic viscosity for all nanofluids. However, for MWCNT/10W40, as the amount of nanoparticles increases, the gradient of growth of dynamic viscosity increases. Findings show that increase in volume fraction does not have a significant effect on rheological behavior of nanofluids and increase in temperature decreases non-Newtonian behavior of nanofluids. However, increase in rate of MWCNT nanoparticles in nanofluid improves non-Newtonian behavior of nanofluids.

Prediction of rheological behavior of SiO2-MWCNTs/10W40 hybrid nanolubricant by designing neural network

This paper assesses the viscosity of 10W40 engine oil containing hybrid nanomaterial at different temperatures using artificial neural network (ANN). The volumetric combination of hybrid nanomaterial is 90% silica (SiO2) and 10% multi-walled carbon nanotubes (MWCNTs). Solid volume fraction, temperatures and shear rate were considered as input variables for ANN, and relative viscosity was output parameter. In order to predict viscosity data of SiO2-MWCNTs (90:10%)/10W40, a comparison between the experimental viscosity and that obtained from previous theoretical models was made. This comparison showed that none of the previous theoretical models were able to estimate the viscosity data. Therefore, a neural network was designed to predict the relative viscosity of hybrid nanolubricant. Artificial neural network function was utilized for viscosity data approximation with excellent precision as R2 value was 0.9948.

Effective lubricant additive of nano-Ag/MWCNTs nanocomposite produced by supercritical CO2 synthesis

Abstract Silver nanoparticles dotted on the external walls of multi-walled carbon nanotubes (MWCNTs) were prepared by an aldehyde reduction process in supercritical carbon dioxide (scCO 2 ) fluid. The silver nanoparticles with narrow size distribution of 5–15 nm are uniformly anchored on MWCNT walls. The prepared nanocomposite of nano-Ag/MWCNTs was used as lubricant additive in 10w40 engine oil and its lubricating performances was evaluated by a four-ball tribometer. The friction coefficient and wear scar diameter were reduced by 36.4% and 32.4% respectively, when the engine oil was dispersed with 0.18 wt % nanocomposite. After synthetically analyzing worn surface by means of scanning electron microscopy and X-ray photoelectron spectroscopy, the lubrication mechanism of this nanocomposite as oil additive is discussed and postulated.

Experimental investigation, model development and sensitivity analysis of rheological behavior of ZnO/10W40 nano-lubricants for automotive applications

In the present study, rheological behavior of ZnO/10W40 nano-lubricant is investigated by an experimental approach. Firstly, ZnO nanoparticles of 10–30nm were dispersed in 10W40 engine oil with solid volume fractions of 0.25–2%, then the viscosity of the composed nano-lubricant was measured in temperature ranges of 5–55°C and in various shear rates. From analyzing the results, it was revealed that both of the base oil and nano-lubricants are non-Newtonian fluids which exhibit shear thinning behavior. Sensitivity of viscosity to the solid volume fraction enhancement was calculated by a new correlation which was proposed in terms of solid volume fraction and temperature. In order to attain an accurate model by which experimental data are predicted, an artificial neural network (ANN) with a hidden layer and 5 neurons was designed. This model was considerably accurate in predicting experimental data of dynamic viscosity as R-squared and average absolute relative deviation (AARD %) were respectively 0.9999 and 0.0502.

Scalable preparation of functionalized graphite nanoplatelets via magnetic grinding as lubricity-enhanced additive

Graphite nanoplatelets were prepared by a novel magnetic-grinding method using self-made equipments. Under a variant magnetic field, magnetic needles collided at a high rotating speed and exfoliated pristine graphite into graphite nanoplatelets with high efficiency. The obtained graphite nanoplatelets are highly crystalline, and the thickness is less than 10 nm. Moreover, the surface area could reached 738.1 m2/g with a grinding time of 4 h. Silanized graphite nanoplatelets can disperse well in SG 15W-40 engine oil and serve as lubricant additive. Tribological results indicate that the friction coefficient and wear-scar of the friction pairs are lower than 76% and 41%, respectively, by adding 1.5‰ (mass fraction) of silanized graphite nanoplatelets. Notably, the functionalized graphite nanoplatelets can realize large-scale production and commercial application.

Feasibility of Observing Small Differences in Friction Mean Effective Pressure between Different Lubricating Oil Formulations Using a Small, Single-Cylinder Motored Engine Rig

The feasibility of using a motored single-cylinder 517 cc diesel engine to observe small frictional differences between oil formulations is investigated. Friction mean effective pressure (FMEP) is measured and compared for an SAE 10W-30 and an SAE 5W-20 oil in three stages of production: base oil, commercial oil without a friction and wear reducing additive, and fully formulated commercial oil. In addition, a commercial SAE 5W-30 engine oil is investigated. Friction mean effective pressure is plotted versus oil dynamic viscosity to compare the lubricant FMEP at a given viscosity. Linear regressions and average friction mean effective pressure are used as a secondary means of comparing FMEP for the various oil formulations. Differences between the oils are observed with the base oil having higher friction at a given viscosity but a lower average FMEP due to the temperature distribution of the test and lower viscosities reached by the base oil. The commercial oil is shown to have both a higher FMEP at a given viscosity and a higher average FMEP than the commercial oil without a friction and wear reducing additive. The increase in friction for the oil without a friction and wear reduction additive indicates that the operational regime of the engine may be out of the bounds of the optimal regime for the additive or that the additive is more optimized for wear reduction. Results show that it is feasible to observe small differences in FMEP between lubricating oil formulations using a small, single-cylinder motored engine.

Ultrasmooth submicrometer carbon spheres as lubricant additives for friction and wear reduction.

Ultrasmooth submicrometer carbon spheres are demonstrated as an efficient additive for improving the tribological performance of lubricating oils. Carbon spheres with ultrasmooth surfaces are fabricated by ultrasound assisted polymerization of resorcinol and formaldehyde followed by controlled heat treatment. The tribological behavior of the new lubricant mixture is investigated in the boundary and mixed lubrication regimes using a pin-on-disk apparatus and cylinder-on-disk tribometer, respectively. The new lubricant composition containing 3 wt % carbon spheres suspended in a reference SAE 5W30 engine oil exhibited a substantial reduction in friction and wear (10-25%) compared to the neat oil, without change in the viscosity. Microscopic and spectroscopic investigation of the carbon spheres after the tribological experiments illustrated their excellent mechanical and chemical stability. The significantly better tribological performance of the hybrid lubricant is attributed to the perfectly spherical shape and ultrasmooth surface of carbon sphere additive filling the gap between surfaces and acting as a nanoscale ball bearing.

Friction Reduction Benefits in Valve-Train System Using IF-MoS2 Added Engine Oil

The development of new advanced lubricants is a key factor for the production of cleaner and more durable internal combustion engines. New improved antifriction and antiwear additives are required. The inclusion of nanoparticles known as solid lubricants (MoS2 and WS2 inorganic fullerenes) in fully formulated engine oils could help to improve the performance of the lubricant and of the engine.The AddNano Consortium, partially funded by the European Commission, investigated the possibility of including inorganic fullerenes in the formulation of engine oils. MoS2 nanoparticles integrated in the additive package of an SAE 5W30 engine oil showed a 50% reduction in the coefficient of friction in tribological lab-scale experiments. The nano-oil was formulated by modifying the additive package in order to stably disperse the nanoparticles and avoid counterproductive interactions with the other components of the package (antifoam, antioxidant, detergents, antiwear and antifriction additives).In the present work, characterization of the nanolubricants on a bench test simulating the real tribological conditions encountered in the valve-train of a diesel engine is reported. transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the nanoparticles and the rubbed surfaces.

Chemically Functionalized Reduced Graphene Oxide as a Novel Material for Reduction of Friction and Wear

Graphene, a lamellar structured material, easily shears at the contact interfaces and exhibits excellent mechanical strength and conductivity, which promises its potential for tribological applications. However, the dispersion of graphene in lube media is a big challenge. Herein, we developed a chemical approach for selective inclusion of long alkyl chains on the edges and defects sites of reduced graphene oxide sheets through the amide linkage, which facilitates their stable dispersion in the lube oil. Chemical and structural features of site-selective chemically functionalized reduced graphene oxide are monitored by FTIR, XPS, XRD, TG-DTA, FESEM, and HRTEM. Tribological test results showed that the chemically functionalized reduced graphene oxide, as an additive to 10W-40 engine oil, significantly reduced both the friction and the wear of steel balls. The stable dispersion of chemically functionalized reduced graphene oxide provides low resistance in a sheared contact owing to weak van der Waals interaction between their lamellas, thus significantly reducing both the friction and the wear.