Recent Advances in Automotive Powertrain Lubrication

A special issue of Lubricants (ISSN 2075-4442).

Deadline for manuscript submissions: 15 December 2024 | Viewed by 9106

Special Issue Editors


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Guest Editor
AC2T Research GmbH, 2700 Wiener Neustadt, Austria
Interests: automotive engine oils; future fuels; artificial ageing; condition monitoring; chemical analysis
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Guest Editor
Department of Propulsion Technology, Széchenyi István University, 9026 Gyor, Hungary
Interests: automotive lubricants; wear analysis; tribotesting

Special Issue Information

Dear Colleagues,

The individual passenger car is still dominant for passenger transport, as are medium and heavy commercial vehicles in logistics. In addition, there is still a strong reliance on internal combustion engines (ICEs) fueled by fossil-based gasoline or diesel, although a shift to electrification is currently taking place in the automobile market. On the other hand, increasingly stringent legal requirements demand stricter emission limits, binding targets for CO2 emission with new and more reliable emission testing under real driving conditions, and improved fuel economy. These facts are highly important driving factors for scientific efforts to develop improved mobility concepts with a special focus on elevated environmental friendliness. Strategies to achieve these goals are manifold.

Given these general conditions, the parameter of suitable component lubrication is a key factor in the development of future automotive powertrains. Thus, this Special Issue aims to give an insight into the recent trends and research directions in the field of automotive lubrication. All state-of-the-art contributions are welcomed to provide a profound summary of current scientific advances.

Dr. Charlotte Besser
Dr. András Lajos Nagy
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Lubricants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • automotive lubricants
  • engine oil
  • transmission oil
  • renewable lubricants
  • nano additives
  • oil degradation
  • oil condition monitoring
  • oil analysis

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Published Papers (5 papers)

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Research

17 pages, 6261 KiB  
Article
Impact of Oil Viscosity on Emissions and Fuel Efficiency at High Altitudes: A Response Surface Methodology Analysis
by Milton Garcia Tobar, Oscar Cabrera Ojeda and Fredy Crespo Montaño
Lubricants 2024, 12(8), 277; https://doi.org/10.3390/lubricants12080277 - 3 Aug 2024
Viewed by 1007
Abstract
This study investigates the effect of oil viscosity on pollutant emissions and fuel consumption of an internal combustion engine (ICE) at high altitudes using a response surface methodology (RSM). A Chevrolet Corsa Evolution 1.5 SOHC gasoline engine was used in Cuenca, Ecuador (2560 [...] Read more.
This study investigates the effect of oil viscosity on pollutant emissions and fuel consumption of an internal combustion engine (ICE) at high altitudes using a response surface methodology (RSM). A Chevrolet Corsa Evolution 1.5 SOHC gasoline engine was used in Cuenca, Ecuador (2560 m above sea level), testing three lubricating oils with kinematic viscosities of 9.66, 14.08, and 18.5 mm2/s, measured at a temperature of 100 °C under various engine speeds and loads. Key findings include the following: hydrocarbon (HC) emissions were minimized from 150.22 ppm at the maximum load to 7.25 ppm with low viscosity and load; carbon dioxide (CO2) emissions peaked at 15.2% vol with high viscosity and load; carbon monoxide (CO) ranged from 0.04% to 3.74% depending on viscosity and load; nitrogen oxides (NOx) were significantly influenced by viscosity, RPM, and load, indicating a need for model refinement; and fuel consumption was significantly affected by load and viscosity. RSM-based optimization identified optimal operational conditions with a viscosity of 13 mm2/s, 1473 rpm, and a load of 78%, resulting in 52.35 ppm of HC, 13.97% vol of CO2, 1.2% vol of CO, 0 ppm of NOx, and a fuel consumption of 6.66 L/h. These conditions demonstrate the ability to adjust operational variables to maximize fuel efficiency and minimize emissions. This study underscores the critical role of optimizing lubricant viscosity and operational conditions to mitigate environmental impact and enhance engine performance in high-altitude environments. Full article
(This article belongs to the Special Issue Recent Advances in Automotive Powertrain Lubrication)
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15 pages, 4170 KiB  
Article
Power Loss Evaluation of an E-Axle Gearbox Considering the Influence of Gear Oil Factors
by Shufa Yan, Zhuo Kong, Hongwei Liu, Lin Zhang, Xiaoyu Hu and Yuanjing Hou
Lubricants 2024, 12(1), 11; https://doi.org/10.3390/lubricants12010011 - 2 Jan 2024
Cited by 1 | Viewed by 1864
Abstract
An accurate power loss prediction in the gearbox is desirable for improving vehicle efficiency. To achieve this objective, evaluating the power loss is necessary. However, power loss is influenced by factors such as the gearbox structure, operating conditions, and gear oil formulation, making [...] Read more.
An accurate power loss prediction in the gearbox is desirable for improving vehicle efficiency. To achieve this objective, evaluating the power loss is necessary. However, power loss is influenced by factors such as the gearbox structure, operating conditions, and gear oil formulation, making power loss evaluation a bottleneck in practice. Therefore, a systematic modeling methodology was developed to evaluate the gearbox power loss in an E-Axle that focuses on the influence of the gear oil factors in the load and no-load cases. The gearbox used in a light-duty truck E-Axle was tested to verify the proposed model. The test was performed under various operating speeds, input loads, and oil temperatures, and four types of gear oil with different formulations were also included to quantify their influence on the power loss. The results showed that the gearbox power loss was significantly influenced by the E-Axle operating conditions, oil temperatures, and different gear oil formulations, promoting different power losses. The comparison results showed good consistency between the predicted power loss and the measured data. The proposed methodology can be utilized to effectively predict the power loss of the E-Axle gearbox and further improve the E-Axle efficiency by selecting suitable oil formulations and adjusting oil temperatures. Full article
(This article belongs to the Special Issue Recent Advances in Automotive Powertrain Lubrication)
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21 pages, 5318 KiB  
Article
Influence of Artificially Altered Engine Oil on Tribofilm Formation and Wear Behaviour of Grey Cast Cylinder Liners
by Martin Jech, Alexander Hofer, Christian Tomastik, Thomas Wopelka and Carsten Gachot
Lubricants 2023, 11(11), 476; https://doi.org/10.3390/lubricants11110476 - 4 Nov 2023
Viewed by 2065
Abstract
This work investigates the influence of altered engine oil on the tribological performance, focusing in particular on wear and interconnected tribofilm formation. For this purpose, Zinc dialkyldithiophosphate (ZDDP) additivated engine oils of different degradation levels, produced in an artificial oil alteration process, were [...] Read more.
This work investigates the influence of altered engine oil on the tribological performance, focusing in particular on wear and interconnected tribofilm formation. For this purpose, Zinc dialkyldithiophosphate (ZDDP) additivated engine oils of different degradation levels, produced in an artificial oil alteration process, were used in tribometer tests with a nitride steel piston ring against a grey cast iron cylinder liner model contact. Parameters were chosen to simulate the boundary and mixed lubrication regime typical for the top dead centre conditions of an internal combustion engine of a passenger car. Wear of the cylinder liner specimens was continuously monitored during the tribometer tests by the radio-isotope concentration (RIC) method, and tribofilms were posteriorly investigated by X-ray photoelectron spectroscopy (XPS). The results clearly show that the steady-state wear rates for experiments with altered lubricants were significantly lower than for the experiments with fresh lubricants. XPS analysis on the formed tribofilms revealed a decrease in sulphide and an increase in sulphate states for altered oils evaluated at 120 °C oil temperature, correlating with a decrease in steady-state wear rate. This finding emphasizes the role of sulphate species in the tribofilm formation process and its anti-wear capabilities, in contrast to the sulphide species and the (poly-)phosphate species, as outlined in most of the ZDDP literature. Moreover, the RIC signal that represents the amount of wear in the engine oil showed a decrease over time for specific altered lubricants and test conditions. These “negative” trends in the wear signal are remarkable and have been identified as an incorporation of wear particles from the lubricant into the tribofilm. This finding is supported by XPS results that detected an iron-oxide layer with a remarkably similar quantity within the tribofilm on the surface. Based on these findings, an assessment of the minimum film formation rate and particle incorporation rate was achieved, which is an important basis for adequate tribofilm formation and wear models. Full article
(This article belongs to the Special Issue Recent Advances in Automotive Powertrain Lubrication)
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18 pages, 8851 KiB  
Article
Influence of Water Contamination, Iron Particles, and Energy Input on the NVH Behavior of Wet Clutches
by Johannes Wirkner, Mirjam Baese, Astrid Lebel, Hermann Pflaum, Katharina Voelkel, Lukas Pointner-Gabriel, Charlotte Besser, Thomas Schneider and Karsten Stahl
Lubricants 2023, 11(11), 459; https://doi.org/10.3390/lubricants11110459 - 27 Oct 2023
Cited by 2 | Viewed by 1493
Abstract
The driving comfort and safety of the automotive powertrain are significantly related to the performance, lifetime, and functionality of the lubricant. The presented study focuses on investigating the performance loss of the lubricant due to water contamination resulting from environmental influences and iron [...] Read more.
The driving comfort and safety of the automotive powertrain are significantly related to the performance, lifetime, and functionality of the lubricant. The presented study focuses on investigating the performance loss of the lubricant due to water contamination resulting from environmental influences and iron particles originating from the wear of different machine elements. The main purpose is to determine critical factors that contribute to the degradation of the lubricant, and increase the tendency to NVH behavior, leading to adverse comfort losses to the respective user. Therefore, this performance loss is evaluated by test rig-based analysis of the friction behavior of wet clutches. Due to physical adsorption, a significant impact of water and iron contamination on the degradation of the lubricant is found, while the influence of the energy input is secondary. Full article
(This article belongs to the Special Issue Recent Advances in Automotive Powertrain Lubrication)
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19 pages, 3592 KiB  
Article
Oil Degradation Patterns in Diesel and Petrol Engines Observed in the Field—An Approach Applying Mass Spectrometry
by Adam Agocs, András Lajos Nagy, Andjelka Ristic, Zsolt Miklós Tabakov, Péter Raffai, Charlotte Besser and Marcella Frauscher
Lubricants 2023, 11(9), 404; https://doi.org/10.3390/lubricants11090404 - 15 Sep 2023
Cited by 1 | Viewed by 1864
Abstract
Engine oil degradation and tribological properties are strongly interrelated. Hence, understanding the chemical processes resulting in additive depletion and degradation products is necessary. In this study, in-service engine oils from petrol and diesel vehicles were analyzed with conventional and advanced methods (mass spectrometry). [...] Read more.
Engine oil degradation and tribological properties are strongly interrelated. Hence, understanding the chemical processes resulting in additive depletion and degradation products is necessary. In this study, in-service engine oils from petrol and diesel vehicles were analyzed with conventional and advanced methods (mass spectrometry). Additionally, the effect of the utilization profile (short- vs. long-range) was studied. Petrol engine oils generally showed accelerated antioxidant and antiwear degradation and higher oxidation, especially in the case of a short-range utilization profile, which can be attributed to the higher air-to-fuel ratio (more rich combustion) compared to diesel engines. A detailed overview of oxidation and nitration products, as well as degradation products resulting from zinc dialkyl dithiophosphate and boron ester antiwear additives, diphenylamine antioxidants and salicylate detergents is given. A side reaction between oxidation products (aromatic carboxylic acids) and the boron ester antiwear is highlighted. This reaction was only detected in the petrol engine oils, where the oxidation products were measured in a high abundance. However, no side reaction was found in the samples from the diesel vehicles, since there the aromatic carboxylic acids were largely absent due to lower oxidation. Full article
(This article belongs to the Special Issue Recent Advances in Automotive Powertrain Lubrication)
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