Low Viscosity Engine Oil Research Articles

Change in Chemical Structure of ZnDTP-Derived Tribofilm Formed from Low-Viscosity Engine Oil by Addition of PMA-Series Polar Compounds

Change in Chemical Structure of ZnDTP-Derived Tribofilm Formed from Low-Viscosity Engine Oil by Addition of PMA-Series Polar Compounds

Does Engine Oil Type Affect Fuel Consumption in Passenger Vehicles? A Two-Year Investigation

Reducing fuel consumption to decrease CO2 emissions has become a key development factor in the automotive industry. An effective way to decrease fuel consumption is to reduce the influence of various sources of energy loss. One way to increase engine efficiency is to use low-viscosity engine oils to reduce friction losses in the engine’s tribological systems. The aim of the article was to analyze the relationship between the type of engine oil and fuel consumption in a group of 12 passenger cars. This was a homogenous group of identical cars, equipped with the same engine, operated under very similar conditions. Three groups of engine oils (Revline, Total, Orlen) were tested in vehicles and stressed with comparable workloads. The experiment was conducted over two years (two stages of research). The collected results were presented using graphs and compared using statistical tests, split into two stages of research, with four seasonal temperature groups. The study provides a detailed description of fuel consumption differences taking into account variations in ambient temperature. The analyses were focused on finding answers to two research questions: does the type of engine oil affect the variation in combustion levels, and what is the variability of fuel consumption in different seasons due to the ambient temperature variability? Briefly, in both stages of the study, vehicles using Revline oil attained the highest average fuel consumption throughout the study period. Vehicles using Total oil showed similar results to those using Revline oil, with the difference in fuel consumption not as noticeable during warmer months. Conversely, vehicles using Orlen oil demonstrated the lowest fuel consumption values during colder months, but higher levels during warmer months.

Effect of additive combinations on tribofilm formation in fully formulated 0W‐8 oil

Reducing engine oil viscosity is an effective way to meet automotive fuel efficiency requirements. Clarifying the effects of multiple coexisting additives in low-viscosity oil is important for the development of low-viscosity engine oil. In this study, six kinds of 0W‐8 engine oil, including those without a Ca-derived detergent, a dispersant or molybdenum dialkyldithiocarbamate (MoDTC), were selected to study the effects of these additives on the tribofilm formation and the friction characteristics of fully formulated low-viscosity oil. A custom-made rolling and sliding tribometer was used to evaluate the tribological properties and form the tribofilms. The elemental distribution of the tribofilms was characterized by electron probe microanalysis (EPMA), and the chemical compositions of the films were determined using X-ray photoelectron spectroscopy (XPS). The Ca-derived detergent hindered both the ZnDTP-derived and MoDTC-derived tribofilm formation in the fully formulated low-viscosity oil due to adsorption competition. The effect of the ashless dispersants on the ZnDTP-derived tribofilm formation in the fully formulated 0W‐8 oil showed opposite results in the presence or absence of MoDTC. The addition of MoDTC had different effects on the ZnDTP-derived tribofilm formation under different additive combinations.

Rapid Separation and API Grades Identification of Base Oil in Low Viscosity Gasoline Engine Oil SN 0W-16.

Using low viscosity engine oil is one of the most economical and easily achievable ways to improve fuel economy. Base oil is a main component in low viscosity engine oils, and therefore, the separation and identification of its are of great significance for oil product developers to prepare high-performance lubricants. However, the extraction methods reported for base oils mainly adopt membrane dialysis, which not only fails to completely separate the base oil but also wastes a large amount of solvent. The reason for this result is that the concentration of substances inside and outside the membrane cannot always be in an imbalanced state of permeation resulting from manual operation. Additionally, most studies primarily focus on the characterization of base oil components, while there are few reports on grade identification. For the above reasons, an economically effective separation technique of base oil from low viscosity gasoline engine oil SN 0W-16 is successfully established by combining improved Soxhlet extraction and a column chromatography separation method. By applying this method, the yield of extracting base oil generally exceeds 96%, and the solvent can also save more than 3 times. Besides, an exclusion method is built through several simple characterization steps including viscosity index (VI), FT-IR, size-exclusion chromatography (SEC), and hydrocarbon composition, which can quickly identify the American Petroleum Institute (API) grade and brand of the base oils.

Numerical Assessment of Tribological Performance of Different Low Viscosity Engine Oils in a 4-Stroke CI Light-Duty ICE

<div class="section abstract"><div class="htmlview paragraph">Decreasing fuel consumption in Internal Combustion Engines (ICE) is a key target for engine developers in order to achieve the CO<sub>2</sub> emissions limits during a standard cycle. In this context, reduction of engine friction could help meet those targets. The use of Low Viscosity Engine Oils (LVEOs), which is currently one of the avenues to achieve such reductions, was studied in this manuscript through a validated numerical simulation model that predicts the friction of the engine’s piston-cylinder unit, journal bearings and camshaft. These frictional power losses were obtained for four different lubricant formulations which differ in their viscosity grades and design. Results showed a maximum friction variation of up to 6% depending on the engine operating condition, where the major reductions came from hydrodynamic-dominated components such as journal bearings, despite an increase in friction in boundary-dominated components such as the piston-ring assembly. Also, an evaluation of the potential fuel reduction that can be obtained by low viscosity oils during a WLTC approval cycle was performed. Overall, a fuel saving of 1% was obtained. In general terms, the majority of the engine map showed potential for mechanical loss reduction through LVEOs, that is, a better engine efficiency and consequently a decrease in the fuel consumption and CO<sub>2</sub> emitted to the atmosphere. The present work also exemplifies the trade-offs encountered when reducing the engine friction through LVEOs and highlights the need to co-engineer the hardware and lubricant in order to utilize the full friction reduction potential of LVEOs.</div></div>

Research on Ultra-High Viscosity Index Engine Oil: Part 1 - “Flat Viscosity” Concept and Contribution to Carbon Neutrality

<div class="section abstract"><div class="htmlview paragraph">In recent years, the realization of carbon neutrality has become an activity to be tackled worldwide, and automobile manufacturers are promoting electrification of power train by HEV, PHEV, BEV and FCEV. Although interest in BEV is currently growing, vehicles equipped with internal combustion engines (ICE) including HEV and PHEV will continue to be used in areas where conversion to BEV is not easy due to lack of sufficient infrastructures. For such vehicles, low-viscosity engine oil will be one of the most important means to contribute to further reduction of CO<sub>2</sub> emissions. Since HEV requires less work from the engine, the engine oil temperature is lower than that of conventional engine vehicles. Therefore, the reduction of viscous resistance in the mid-to-low temperature range below 80°C is expected to contribute more to fuel economy. On the other hand, the viscosity must be kept above a certain level to ensure the performance of hydraulic devices in the high oil temperature range. In order to achieve both of these characteristics, an oil whose viscosity has smaller temperature dependency (flat viscosity oil) is required. The flat viscosity oil can be achieved by using a low-evaporative, low-viscosity base oil and an ultra-high viscosity index Viscosity Modifier. It proved the possibility to achieve fuel economy equal to or better than 0W-8 while maintaining 0W-16 equivalent high temperature viscosity. This technology is applicable for vehicles calibrated with either 0W-16 or 0W-8 without negative impact on fuel economy performance. The flat viscosity 0W-16 will improve the fuel economy of in-use vehicles calibrated with conventional 0W-16 oils in the market significantly. As a result, CO<sub>2</sub> reduction can be achieved not only for new vehicles but also for vehicles in operation in the market that can contribute greatly to the carbon neutrality. In order for the flat viscosity oil to be widely used in the world, it is necessary to establish new engine oil specification.</div></div>

Optimizing the Mo concentration in low viscosity fully formulated oils

Molybdenum dithiocarbamate (MoDTC) is usually added in low viscosity engine oils to improve its ability to reduce friction. However, increasing the amount of MoDTC added results in unwanted sulfated ash increases and other adverse effects. Thus, it is necessary to investigate the optimization of the amount of MoDTC added. The current work investigates this topic in terms of the Mo concentration in the lubricant. Seven different Mo concentrations with the same additive package are tested, whose tribological properties and chemistry of the tribofilm are investigated. For the selected operating conditions in this study, the critical concentration of Mo is determined to be ≈ 350 ppm due to its ability to reduce the friction to ≈ 0.04 under a constant and varying lambda ratio by forming the required threshold thickness of MoS2 within the tribofilm matrix, dominated by zinc dialkyl dithiophosphate (ZDDP) species. In general, increasing the Mo concentration increases the formation rate of MoS2 in the initial stages of the traction, directly forming a thicker MoS2 layer within the tribofilm up to a specific Mo concentration. Induction time also decreases with increasing Mo concentration, and increasing the Mo concentration from 350 to 1000 ppm does not negatively impact the wear generated.

Using Ionic Liquid Additive to Enhance Lubricating Performance for Low-Viscosity Engine Oil

Using Ionic Liquid Additive to Enhance Lubricating Performance for Low-Viscosity Engine Oil

Synergistic and Competitive Effects between Zinc Dialkyldithiophosphates and Modern Generation of Additives in Engine Oil

The increasing demand for low-viscosity engine oil has underscored the role of zinc dialkyldithiophosphates (ZDDP) as a conventional anti-wear and antioxidant additive. It is essential to investigate the influence of modern additives such as cyclopropanecarboxylic acid (CPCa) and Ni nanoparticles on the tribological performance of ZDDP for practical commercial oil application. According to the experimental results, Ni nanoparticles formed a protective film that exhibited a synergistic effect with ZDDP. A significantly higher concentration of sulphur in the tribofilm was detected compared to ZDDP by itself, which was responsible for a 27.6% lower wear loss. Meanwhile, a competitive effect between CPCa and ZDDP resulted in a dramatic increase in friction and unstable anti-wear performance. This was demonstrated by a localized formation of the ZDDP tribofilm on the wear surfaces after the friction test. These results have highlighted the synergistic and competitive effects of emerging additives (CPCa and Ni nanoparticles) in the ZDDP tribofilm formation between the sliding steel contacts. This further suggests a new approach to increase the efficiency of ZDDP’s tribological performance at cold start-up processes.

Effect of Dispersant Concentration With Friction Modifiers and Anti-Wear Additives on the Tribofilm Composition and Boundary Friction

Abstract To extend drain intervals and improve efficiency, new engine oils with increased dispersant concentration and reduced viscosity are required. Low viscosity engine oils can increase the prevalence of boundary friction at low temperature and increase its severity at higher temperatures. As a result, combinations of organic and inorganic friction modifiers (FM) will be used to reduce boundary friction across a range of temperatures, also preventing damage to vehicle catalysts. This paper presents an experimental case study of such a new generation of fully formulated engine lubricants with varying concentrations of polyisobutylene succinimide dispersant, organic, and inorganic FM. Representative conditions pertaining to those encountered at the top dead center reversal of the piston compression ring-cylinder liner contact are created, and the generated friction measured through use of a sliding-strip tribometry. Subsequently, X-ray photoelectron spectroscopy (XPS) is used to determine the composition of the formed surface tribofilms in order to explain the observed frictional characteristics. The key interactions and frictional behavior of the dispersant and friction modifiers are highlighted across a range of operating temperatures.

Influence of crystal grain structure of steel surface on formation of chemical reaction film derived from engine oil additives

This study investigated the relationship between the chemical reaction film formation derived from engine oil additives and crystal grain structure of a steel surface. Variations in the contact area between a rotating sapphire disc and a stationary steel pin were captured by a monochromatic high-speed camera. A fully formulated low viscosity engine oil was used as the lubricant. After friction tests, the elements on the surface were analysed using energy dispersive X-ray spectroscopy and the crystal grain structure of the top surface layer by electron backscatter diffraction. In-situ and ex-situ analyses revealed that plastic flow changed the crystal grain structure of the surface, inhibiting the formation of the chemical reaction film derived from additives.

Methylenealkane-Based Low-Viscosity Ester Oils: Synthesis and Outlook

Both Group 4 poly-α-olefin (PAO) and Group 5 ester oil basestocks are used in formulations of synthetic engine oils, transmission fluids, and lubricants with leading characteristics such as low viscosity (providing fuel saving), high stability, and environmental safety. The modern technologies of the production of PAOs use catalytic oligomerization of α-olefins, which is complicated by the formation of low-molecular-weight α-olefin dimers (methylenealkanes) as imminent side products. The use of methylenealkanes as raw materials for the synthesis of Group 5 base stocks appears to be highly promising. In the present work, we report the use of methyl 3-butylnonanoate and methyl 3-hexylundecanoate, the products of catalytic methoxycarbonylation of hex-1-ene and oct-1-ene dimers, in the synthesis of two series of branched isomeric esters. These esters demonstrated excellent rheological behavior and may be considered as low-viscosity engine oils with leading characteristics.

The use of non-cavitating coupling fluids for intensifying sonoelectrochemical processes.

For the first time, we have investigated the beneficial effects of non-cavitating coupling fluids and their moderate overpressures in enhancing mass-transfer and acoustic energy transfer in a double cell micro-sonoreactor. Silicon and engine oils of different viscosities were used as non-cavitating coupling fluids. A formulated monoethylene glycol (FMG), which is a regular cooling fluid, was also used as reference. It was found that silicon oil yielded a maximum acoustic energy transfer (3.05W/cm2) from the double jacketed cell to the inner cell volume, at 1bar of coupling fluid overpressure which was 2.5 times higher than the regular FMG cooling fluid. It was also found that the low viscosity engine oil had a higher acoustic energy value than that of the high viscosity engine oil. In addition, linear sweep voltammograms (LSV) were recorded for the quasi-reversible Fe2+/Fe3+ redox couple (equimolar, 5×10-3 M) on a Pt electrode in order to determine the mass-transport limited current density (jlim) and the dimensionless Sherwood number (Sh). From the LSV data, a statistical analysis was performed in order to determine the contribution of acoustic cavitation in the current density variation |Δj|average. It was found that silicon oil at 1bar exhibited a maximum current density variation, |Δj|average of ~2mA/cm2 whereas in the absence of overpressure, the high viscosity engine oil led to a maximum |Δj|average which decreased gradually with increasing coupling fluid overpressure. High viscosity engine oil gave a maximum Sh number even without any overpressure which decreased gradually with increasing overpressure. The Sh number for silicon oil increased with increasing overpressure and reached a maximum at 1bar of overpressure. For any sonoelectrochemical processes, if the aim is to achieve high mass-transfer and acoustic energy transfer, then silicon oil at 1bar of overpressure is a suitable candidate to be used as a coupling fluid.

Lipophilic magnetite nanoparticles coated with stearic acid: A potential green and low cost way to improve thermal stability and tribological properties of fully formulated low viscosity engine oils

Lipophilic nanoparticles of magnetite (d≈10 nm) functionalized with stearic acid (MagNP) were tested as additive in modern engine oil with low viscosity and high additization. Its thermal and tribological properties were evaluate using TG/DTA and a high frequency reciprocating tribometer, respectively. All tests were performed with the neat oil and the oil+MagNP. The analysis showed that MagNP: i) improved thermal stability of the engine oil; ii) kept friction values lower and more stable; iii) drastically reduce wear marks; iv) improved the deposition of additives from the lubricating oil onto the worn surface.

A methodology to estimate mechanical losses and its distribution during a real driving cycle

Reducing mechanical losses in internal combustion engines has been a recurrent research topic over the past few decades. Despite mechanical losses are a key issue that should be carefully addressed to reduce fuel consumption and emissions, its distribution amongst engine elements is barely covered in literature. Recent work has shown the potential advantage of using low viscosity engine oils to reduce fuel consumption, however, there is reduced knowledge on mechanical losses distribution under transient conditions. In this work, a model is presented that predicts not only the total friction losses of an engine, but determines the amount of friction energy lost in piston-ring assembly, engine bearings, camshaft and engine auxiliaries in driving cycles representing a real driving route. The stationary mechanical losses engine maps can be used due to non-dependence on mechanical losses with temperature in warm driving cycle conditions. The final results of the simulation predicts, with 2% error, fuel consumption, energy expended by the driven wheel and mechanical losses of the engine. This methodology reduces the computational cost to estimate key engine parameters in a real driving cycle such as: mechanical losses and its distribution, fuel consumption... as the total calculation time is 10 s per cycle simulated.

Fuel Economy Performance of MoDTC in Low Viscosity Engine Oil

Fuel Economy Performance of MoDTC in Low Viscosity Engine Oil

Многофункциональное масло для наземной военной техники армии США

The U.S. Army has a desire to consolidate multiple MIL specification fluids into a single specification, or Single Common Powertrain Lubricant (SCPL) program. This program is seeking to develop an all-season (arctic to desert), fuel-efficient, multi-functional powertrain fluid with extended drain capabilities and designed to consolidate multiple military lubricant specifications into a single product, or single specification. This paper covers the long term field demonstration programs of the SCPL conducted three locations, representing basic, arctic, and desert climate conditions respectively. Overall the field demonstration for all three locations was considered successful. Real world military vehicle operation using SCPL did not show any differences from currently fielded MIL-PRF-2104 and MIL-PRF-46167 products. In addition, the durability of the SCPL over the one and two year test durations showed that the SCPL is capable of extended drain intervals than the current annual oil change recommendations. These results confirms that the SCPL is a drop in replacement, and is providing improved overall performance compared to currently fielded products. The use of low viscosity engine oil was shown to have a significant impact on fuel consumption: the difference between the current MIL-PRF-2104H SAE 15W-40 grade and the best experimental fluid had an improvement of 1.66% over the test cycle.

Engine Oil Fuel Economy: Benefits and Potential Debits of Low Viscosity Engine Oil

<div class="section abstract"><div class="htmlview paragraph">There has been a trend in the automotive industry toward the use of lower viscosity engine oils as fuel economy requirements become more demanding across the globe. Lower viscosity fluids may improve fuel economy due to their improved pumpability, lower churning losses, and thinner lubricating films. However, there is one important caveat related to the use of these fluids: the amount of improvement, if any, is hardware design and application dependent. Standard industry fuel economy tests and engines with differing designs may show divergent responses when using lower viscosity engine oils, not always showing an improved fuel economy response. This paper summarizes the work conducted by the authors to demonstrate how and why the inconsistent results in fuel economy can occur with low viscosity oils.</div></div>

Devising Carbon Nanotube, Green Tea, and Polyaniline Based Nanocomposite plus Investigating Its Rheological together with Bactericidal Efficacies.

Subsequently, engines are designed to operate at low viscosity engine oils. Low viscosity oils take less power from engines, bring down the internal drag, cut the fuel consumption, and ultimately improve the engine’s efficiency. Considering this focus, an approach has been made to formulate a multiwalled carbon nanotube based green tea and polyaniline nanocomposite, that is, GT/MWCNT/PANI, and incorporate it in engine oil (base fluid). The objective was to reduce the viscosity of engine oil by examining the effects of the constant shear rate and varying shear rates on the viscosity of Castrol class 15W-40 engine oil. The investigation was performed at a constant temperature of 25 °C for a fixed volume fraction of 0.1% GT/MWCNT/PANI in engine oil on the experimental setup rheometer from Anton Paar Series. Primordial findings revealed that, at a constant shear rate of 100 s–1, engine oil viscosity was lowered from 0.221000 to 0.001402 Pa·s, that is, 99% reduction in viscosity of the engine oil, after incorporating the GT/MWCNT/PANI nanocomposite. Furthermore, a new correlation has been proposed considering the experimental and theoretical models with an average percentage error of 0.040%. Also, at varying shear rates, up to 90 s–1, the shear viscosity of nanofluid decreases significantly, leading to shear-thinning behavior of the nanofluid, while at a shear rate of >90 s–1, it shows Newtonian behavior. Besides, the ternary nanocomposite with 0.2 wt % GT/MWCNT/PANI also showed significant bactericidal effects with the zones of inhibition of 19, 18, and 15 mm against Gram-negative (Pseudomonas aeruginosa, Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, respectively, as measured using the well diffusion method.

Comparison of natural and synthetic sorbents’ efficiency at oil spill removal

The spill of crude oil products into the environment has a negative impact on the ecosystem. Sorption materials are utilized as the means of their elimination. The sorption capacity of selected organic and inorganic natural sorbents, such as needles (Larix decidua, Abies alba, and Pinus sylvestris), sawdust from logging (Fagus sylvatica, Picea abies), leaf residues (Fagus sylvatica), moss (Ceratodon purpureus), soil, and synthetic sorbents Absodan Plus, expanded perlite, Eco-dry plus, and Reo Amos were all tested according to the standard ASTM F726 (2012). The natural sorbents were tested at various moisture contents (wet, air-dry, and dry) ranging from 0 to 82%. The pollutant used in the experiment was the low-viscosity engine oil 10W 40. The best sorption capacity among the wet sorbents was achieved with larch needles (11.1 g/g). Moss exhibited the best sorption capacity (25.2 g/g) among the air-dry sorbents. Regarding air-dry sorbents, larch needles, spruce sawdust, and beech sawdust showed the best results. When further dried, their sorption capacity decreased. Soil was the least efficient natural sorbent with a sorption capacity that ranged from 0.45 to 3.82 g/g. The best sorption capacity of 11.5 g/g among the synthetic sorbents was in Reo Amos. The sorption capacity of natural and synthetic substances was comparable.