Advances in Tribology and LCA Applied to Thermal Machines

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

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 22153

Special Issue Editors

Programa de Ingeniería Mecánica, Universidad del Atlántico, Carrera 30 Número 8-49, Puerto Colombia, Barranquilla 080007, Colombia
Interests: internal combustion engine; exergo-environmental analysis; fluid simulation; lubrication; waste heat recovery system
Programa de Ingeniería Mecánica, Universidad del Atlántico, Carrera 30 Número 8-49, Puerto Colombia, Barranquilla 080007, Colombia
Interests: internal combustion engine; exergo-environmental analysis; LCA; waste heat recovery system
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Throughout history, there has been a constant growth in the use of thermal machines to generate electrical energy and power. These thermal machines have different technical and operational characteristics; therefore, it has been necessary to develop advanced lubrication systems and fluids for these types of equipment. Similarly, there is a need to study the environmental impact of using advanced lubrication systems and other fluids applied to thermal machines, and the materials used in their manufacturing and operation. Previous descriptions prove the importance of environmental impact in the current designs of lubrication systems.

Despite the constant evolution of technology, there is a continuous loss of heat energy in thermal machines. For this reason, attempts to improve the thermal machine's performance by reducing wasted energy have been partially successful. Thermal machines have limitations in their thermal performance due to the physical laws that support their operation. For this reason, it is essential to develop efficient procedures to improve the effects of proper lubrication systems in these machines.

The current Special Issue concerns the latest developments of tribology and LCA applied to thermal machines. These developments also involve a rheology approach, a simulation of phenomena in lubrication systems, the development of new materials and manufacturing processes, and the life cycle assessment. This Issue is expected to generate new knowledge in this specific research field, with environmental impact strategies and improvements in design approaches for these important machines, which are used worldwide.

Prof. Dr. Jorge Duarte Forero
Prof. Dr. Guillermo Valencia Ochoa
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

  • Carbon footprint analysis
  • Thermal machine
  • Life Cycle Assessment
  • Lubricants
  • Lubrication
  • Materials
  • Modeling

Published Papers (9 papers)

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Research

22 pages, 15280 KiB  
Article
CFD Analysis of the Effect of Dimples and Cylinder Liner Honing Groove on the Tribological Characteristics of a Low Displacement Engine
Lubricants 2022, 10(4), 61; https://doi.org/10.3390/lubricants10040061 - 07 Apr 2022
Cited by 4 | Viewed by 2106
Abstract
The contact between the piston rings and the cylinder liner is an interface with a strong influence on the tribological behavior and, therefore, directly affects the useful life of the engine components and fuel consumption. Due to this importance, the present investigation carried [...] Read more.
The contact between the piston rings and the cylinder liner is an interface with a strong influence on the tribological behavior and, therefore, directly affects the useful life of the engine components and fuel consumption. Due to this importance, the present investigation carried out an analysis of the effects of dimples and the honing groove in the cylinder liner on the tribological characteristics. A tribological model was developed to study the friction forces, minimum film thickness, and friction coefficient for the present investigation. Similarly, a computational fluid dynamics model was built to determine the dynamic movement of the piston. The validation of the numerical model showed a close similarity with the real behavior of the engine, obtaining an average relative error of 14%. The analysis of the results showed that a 3% increase in dimples’ density leads to a 3.79% increase in the minimum lubricant film and a 2.76% decrease in friction force. Additionally, it was shown that doubling the radius and depth of the dimple produces an increase of 3.86% and 1.91% in the thickness of the lubrication film. The most suitable distribution of the dimples on the surface of the cylinder liner corresponds to a square array. In general, the application of dimples and honing grooves in the cylinder liner are promising alternatives to reduce energy losses and minimize wear of engine components. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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17 pages, 38062 KiB  
Article
Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine
Lubricants 2022, 10(4), 60; https://doi.org/10.3390/lubricants10040060 - 07 Apr 2022
Cited by 4 | Viewed by 1794
Abstract
In the present investigation, a study is carried out using numerical simulation on the effects of cylinder deactivation on tribological parameters and emissions in an internal combustion engine. For the development of the research, a tribological model was used to predict the characteristics [...] Read more.
In the present investigation, a study is carried out using numerical simulation on the effects of cylinder deactivation on tribological parameters and emissions in an internal combustion engine. For the development of the research, a tribological model was used to predict the characteristics of the lubrication film, friction conditions, blow-by gas, and deformation of the piston rings. Additionally, the construction of a CFD model was carried out to describe the kinematic movement of the engine piston. The analysis of results allowed for the demonstration of the active cylinders presenting an increase of 21.53% and 7.65% in the pressure and temperature in the cylinder wall. Additionally, the active cylinders present a reduction of 11.33% in the minimum thickness of the lubrication film and an increase in the friction force due to asperities, which implies an increase of 33% in power losses due to friction. The implementation of technologies such as cylinder deactivation causes an increase in combustion gas leaks caused by the increase in pressure of the active cylinders. However, the use of this technology allows reducing 9.09%, 8.26%, and 7.41% in CO, HC, and NO emissions. Although the use of technologies such as cylinder deactivation allows significant fuel savings, it is necessary to consider the negative effects caused by this technology, such as the increase in combustion gas leaks and the increase in power loss by the greatest frictional forces. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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15 pages, 5542 KiB  
Article
Investigation of Emission Characteristics and Lubrication Oil Properties in a Dual Diesel–Hydrogen Internal Combustion Engine
Lubricants 2022, 10(4), 59; https://doi.org/10.3390/lubricants10040059 - 05 Apr 2022
Cited by 6 | Viewed by 3035
Abstract
Hydrogen is considered one of the main gaseous fuels due to its ability to improve thermal performance in diesel engines. However, its influence on the characteristics of lubricating oil is generally ignored. Thus, in the present investigation, an analysis of the effect on [...] Read more.
Hydrogen is considered one of the main gaseous fuels due to its ability to improve thermal performance in diesel engines. However, its influence on the characteristics of lubricating oil is generally ignored. Thus, in the present investigation, an analysis of the effect on the physical and chemical properties of lubricating oil with mixtures of diesel fuel–hydrogen was carried out, and the environmental impacts of this type of mixture were assessed. The development of the research was carried out using a diesel engine under four torque conditions (80 Nm, 120 Nm, 160 Nm and 200 Nm) and three hydrogen gas flow conditions (0.75 lpm, 1.00 lpm and 1.25 lpm). From the results, it was possible to demonstrate that the presence of hydrogen caused decreases of 3.50%, 6.79% and 4.42% in the emissions of CO, HC, and smoke opacity, respectively. However, hydrogen further decreased the viscosity of the lubricating oil by 26%. Additionally, hydrogen gas produced increases of 17.7%, 29.27%, 21.95% and 27.41% in metallic components, such as Fe, Cu, Al and Cr, respectively. In general, hydrogen favors the contamination and oxidation of lubricating oil, which implies a greater wear of the engine components. Due to the significantly negative impact of hydrogen on the lubrication system, it should be considered due to its influence on the economic and environmental cost during the engine’s life cycle. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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18 pages, 7952 KiB  
Article
Study of the Kinematics and Dynamics of the Ring Pack of a Diesel Engine by Means of the Construction of CFD Model in Conjunction with Mathematical Models
Lubricants 2021, 9(12), 116; https://doi.org/10.3390/lubricants9120116 - 28 Nov 2021
Cited by 6 | Viewed by 2184
Abstract
The present research aims to analyze the kinematic and dynamic behavior of the piston ring package. The development of the research was carried out through the development of numerical simulation by means of CFD. The analysis involves the three piston rings for the [...] Read more.
The present research aims to analyze the kinematic and dynamic behavior of the piston ring package. The development of the research was carried out through the development of numerical simulation by means of CFD. The analysis involves the three piston rings for the development of simulations that are closer to the real conditions of the engine since most of the investigations tend to focus on the study of the compression ring only. The simulation was reinforced by the incorporation of mathematical models, which allow determining the piston kinematics, the lubrication properties as a function of temperature, contact friction, and gas leakage. For the simulation, the CAD of the piston and the connecting rod—crankshaft mechanism was carried out, taking as a reference the geometry of a diesel engine. From the results obtained, it was possible to show that the first ring exhibits considerably greater radial and axial movement compared to the second and third piston rings. Additionally, it was shown that the first and second rings tend to maintain a negative tilt angle throughout the combustion cycle, which facilitates the advancement of the combustion gases over the piston grooves. Therefore, it is necessary to use strategies so that these rings tend to maintain a positive inclination. The analysis of the pressure conditions in the second ring are 150% and 480% higher compared to the conditions present in the third ring. Due to the above, it is necessary to focus efforts on the design of the profile of this ring. The study of energy losses showed that the combination of leakage gases and friction are responsible for a mechanical loss between 6–16%. In general, the development of the proposed methodology is a novel tool for the joint analysis of the kinematic characteristics, pressure conditions, and energy losses. In this way, integrated analysis of changes caused by piston ring designs is possible. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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27 pages, 8371 KiB  
Article
A New Computational Tool for the Development of Advanced Exergy Analysis and LCA on Single Effect LiBr–H2O Solar Absorption Refrigeration System
Lubricants 2021, 9(8), 76; https://doi.org/10.3390/lubricants9080076 - 05 Aug 2021
Cited by 6 | Viewed by 2510
Abstract
A single effect LiBr–H2O absorption refrigeration system coupled with a solar collector and a storage tank was studied to develop an assessment tool using the built-in App Designer in MATLAB®. The model is developed using balances of mass, energy, [...] Read more.
A single effect LiBr–H2O absorption refrigeration system coupled with a solar collector and a storage tank was studied to develop an assessment tool using the built-in App Designer in MATLAB®. The model is developed using balances of mass, energy, and species conservation in the components of the absorption cooling system, taking into account the effect of external streams through temperature and pressure drop. The whole system, coupled with the solar energy harvesting arrangement, is modeled for 24 h of operation with changes on an hourly basis based on ambient temperature, cooling system load demand, and hourly solar irradiation, which is measured and recorded by national weather institutes sources. Test through simulations and validation procedures are carried out with acknowledged scientific articles. These show 2.65% of maximum relative error on the energy analysis with respect to cited authors. The environmental conditions used in the study were evaluated in Barranquilla, Colombia, with datasets of the Institute of Hydrology, Meteorology and Environmental Studies (IDEAM), considering multiannual average hourly basis solar irradiation. This allowed the authors to obtain the behavior of the surface temperature of the water in the tank, COP, and exergy efficiency of the system. The simulations also stated the generator as the biggest source of irreversibility with around 45.53% of total exergy destruction in the inner cycle without considering the solar array, in which case the solar array would present the most exergy destruction. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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25 pages, 11157 KiB  
Article
Analysis of the Influence of Textured Surfaces and Lubrication Conditions on the Tribological Performance between the Compression Ring and Cylinder Liner
Lubricants 2021, 9(5), 51; https://doi.org/10.3390/lubricants9050051 - 06 May 2021
Cited by 4 | Viewed by 2055
Abstract
The objective of the present investigation is to analyze the tribological performance between the union of the cylinder liner and the compression ring under the influence of surface texturing and different lubrication boundary conditions. The analysis is carried out by developing a numerical [...] Read more.
The objective of the present investigation is to analyze the tribological performance between the union of the cylinder liner and the compression ring under the influence of surface texturing and different lubrication boundary conditions. The analysis is carried out by developing a numerical model, which involves hydrodynamic pressure, lubrication film thickness, textured surface, dynamic forces, and lubrication boundary conditions (starved lubrication and fully flooded lubrication). MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used to solve the equations developed. The results show that the application of a textured surface on the cylinder liner allows obtaining a reduction of 20% and 5% in the asperity contact force and in the total friction force. Additionally, the textured surface allows for a 4% increase in MOFT. In this way, it is possible to reduce the power loss. The implementation of a boundary condition of fully flooded lubrication produces an overestimation in the total friction force due to the greater prominence of the lubrication film. Implementing a textured surface in the ring profile is an alternative way to reduce power loss. The results show that this alternative allows an 8% reduction in power loss. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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22 pages, 8074 KiB  
Article
A Numerical Model for the Analysis of the Bearings of a Diesel Engine Subjected to Conditions of Wear and Misalignment
Lubricants 2021, 9(4), 42; https://doi.org/10.3390/lubricants9040042 - 09 Apr 2021
Cited by 4 | Viewed by 1779
Abstract
In the present work, a numerical model is developed to investigate the influence of wear and misalignment on the bearings of a stationary diesel engine. The model implemented considers the effects of surface wear on the bearing, cavitation effects, and surface roughness. For [...] Read more.
In the present work, a numerical model is developed to investigate the influence of wear and misalignment on the bearings of a stationary diesel engine. The model implemented considers the effects of surface wear on the bearing, cavitation effects, and surface roughness. For the numerical analysis, changes in the surface roughness of σμσ=0.75 μm, σμσ=1 μm, and σμσ=1.25 μm are defined, and changes in the bearing load of 50%, 75%, and 100%. The results demonstrated that increasing the surface roughness intensifies the bearing wear, which represents 18% and 140% of the bearing clearance for the roughness of σμσ=1 μm and σμσ=1.25 μm, respectively. Additionally, the surface roughness causes a considerable increase in the bearing wear rate. The results described a maximum wear rate of μ20 μm/s. In general, increasing the bearing load by 25% doubles the hydrodynamic pressure conditions increases friction force by 33%, and reduces lubrication film thickness by 12%. The analysis of the angle of deflection, ϕx and ϕy, shows that the moment and the degree of misalignment tend to increase significantly with the increase in the magnitude of the angle ϕy. Negative angles of deflection, ϕx, produce a greater increase in the degree of misalignment and the moment. This implies a greater chance of contact with the bearing surface. In conclusion, the proposed methodology serves as a reliable tool to simultaneously evaluate key parameters on the tribological behavior of bearings that further extend their endurance and minimize wear damage. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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28 pages, 7733 KiB  
Article
Influence of Compression Rings on the Dynamic Characteristics and Sealing Capacity of the Combustion Chamber in Diesel Engines
Lubricants 2021, 9(3), 25; https://doi.org/10.3390/lubricants9030025 - 02 Mar 2021
Cited by 16 | Viewed by 2933
Abstract
Internal combustion engines are widely implemented in several applications; however, they still face significant challenges due to the sealing capacity of the compression rings. Gas leakage through the crankcase, also known as blow-by, directly impacts power losses, overall efficiency, and global emissions. Therefore, [...] Read more.
Internal combustion engines are widely implemented in several applications; however, they still face significant challenges due to the sealing capacity of the compression rings. Gas leakage through the crankcase, also known as blow-by, directly impacts power losses, overall efficiency, and global emissions. Therefore, the present study investigates the influence of parameters such as the ring gap, ring masses, and twist angle of the compression rings on the sealing capacity of the combustion chamber. A mathematical model is proposed to account for geometric, dynamic, and operational characteristics in a single-cylinder diesel engine. The results indicated that the greatest gas losses to the crankcase occur during the compression and combustion stages as a consequence of extreme pressure conditions. Specifically, at least 0.5% of the gases locked in the combustion chamber are released on each cycle, while increasing the mass of the compression rings boosts the gas leakage due to higher inertial forces in the rings. In contrast, a positive twist angle of the compression rings reduced the combustion gases leakage by 7.33×105 g/cycle. Additionally, a combined reduction in the gap of both compression rings minimized the leakage flows by 37%. In conclusion, the proposed model served as a robust tool to evaluate different parameters on the sealing capacity of the combustion chamber that contribute to minimizing global emissions. Secondary piston motion and ring distortion represent significant opportunities in future studies. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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23 pages, 6108 KiB  
Article
Numerical and Experimental Analysis of the Potential Fuel Savings and Reduction in CO Emissions by Implementing Cylinder Bore Coating Materials Applied to Diesel Engines
Lubricants 2021, 9(2), 19; https://doi.org/10.3390/lubricants9020019 - 18 Feb 2021
Cited by 5 | Viewed by 2029
Abstract
Currently, internal combustion engines contribute to the problem of global warming due to their need to use products derived from fossil resources. To mitigate the above problem, this study proposes the use of coatings on the cylinder bore in order to reduce fuel [...] Read more.
Currently, internal combustion engines contribute to the problem of global warming due to their need to use products derived from fossil resources. To mitigate the above problem, this study proposes the use of coatings on the cylinder bore in order to reduce fuel consumption and polluting emissions. Therefore, in the present study a numerical model is developed in which the tribological behavior, heat fluxes, and leakage of the combustion gases in the chamber are considered to evaluate the influence of the coating. Nickel nanocomposite (NNC) and diamond-like carbon (DLC) coatings are considered in the study. The results demonstrate that the NNC coating produces a 32% reduction in the total friction force of the compression ring. The estimated maximum temperatures for the lubricating oil were 214, 202, and 194 °C for the DLC, steel, and NNC materials. Increasing the temperature in the DLC coating can cause a reduction in the tribological performance of the lubricant. The estimates made show that the implementation of the NNC coating allows a maximum reduction of 5.28 ton of fuel and 39.30 kg of CO emissions, which are based on the global fleet of diesel engines forecast for the year 2025 (corresponding to one hundred and eighty million engines) and a test time of 1800 s. The proposed numerical model allows future analyses to be carried out for other types of materials used as coatings. Additionally, the model can be expanded and adapted to consider other systems that involve friction processes in the engine. Full article
(This article belongs to the Special Issue Advances in Tribology and LCA Applied to Thermal Machines)
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