Browse Topic: Lubricating oils

Items (1,907)

Development of Electric Vehicle Oils with High Energy Efficiency and Cooling Performance by Applying Novel Friction Modifier

2026-01-5064

7/31/2026

Improving the efficiency of electric vehicle (EV) transmissions can help to extend the driving range of EVs, and the EV oil used in these transmissions plays an important role. In this study, in order to enhance energy efficiency, we examined the effects of lowering viscosity, traction, and friction in EV oil. While friction modifiers (FMs) have been widely used as friction reduction technologies in the field of tribology for many years, we previously developed a new FM that reduces friction in drive units. We found that a combination of lowering viscosity and using the developed FM was effective for better energy efficiency. The oil formulated with the developed FM improved efficiency by approximately +0.8% to +0.9% compared to commercial EV oil. EV oil also requires cooling performance. We assumed that reducing heat generation through friction reduction would improve cooling performance and examined the effect of lowering viscosity, traction, and friction. Consequently, it was found that a combination of lowering traction and applying the developed FM is effective for reduction in parasitic heat losses. We also examined durability, which is an issue when reducing viscosity. The results suggested that the oil formulated with the developed FM had good durability for gears and bearings. Thus, we succeeded in developing an ultra-low-viscosity EV oil that has excellent energy efficiency and high cooling performance.

Nakamura, Toshitaka, Furuse, Takashi, Hasegawa, Shinji, Akahori, Shinya, Itou, Kimikazu, Sakurada, Soichiro, Akiguchi, Junnosuke

Optimization of Preheating Energy Distribution for Low-Temperature Cold Starts in Diesel-Electric Hybrid Vehicles

2026-99-0516

7/10/2026

To minimize energy input and preheating time, this study first analyzed the energy consumption of intake air, lubricating oil, and coolant preheating through simulations. Temperature rise data were collected under various heating parameters. Next, simulations evaluated the hybrid power system’s resistance characteristics immediately after startup and the combustion parameters during the first cycle post-ignition under different temperatures. The temperature thresholds for successful start-up were identified, defining the feasible domain for optimization. Optimization calculations aimed to minimize preheating time and energy input, constrained by maximum preheating power. Results show that intake air heating has the greatest impact on start-up success, followed by lubricating oil heating. It is recommended to increase energy allocation to intake air and lubricating oil heating. This optimized strategy reduces preheating time and energy input by approximately 26% without changing the preheating equipment.

Wei, Shengchen, Zhao, Zhenfeng

Numerical Analysis of Pre-Ignition Factors in Hydrogen Engines

2026-01-0740

7/1/2026

Numerical analysis was conducted to investigate abnormal combustion, a major challenge in efforts to improve hydrogen engine efficiency. Focusing on two factors that induce abnormal combustion—surface reactions and lubricating oil—numerical analysis examined the potential for each to trigger abnormal combustion. Furthermore, since it was confirmed that the autoignition prediction using a detailed chemical reaction mechanism deviates from experiments at temperatures around 800K, attempts were made to improve this issue. As a result, it was confirmed that surface reactions affect the chemical species ratio near the wall surface but have little effect on flame propagation. Regarding lubricating oil, two possibilities were investigated: the lubricating oil itself self-igniting and becoming an ignition source for the hydrogen mixture, and deposits generated from the lubricating oil generating heat and becoming an ignition source. The results of these investigations showed that autoignition occurs before top dead center in both cases: when lubricating oil is present in the mixture during the compression stroke and when deposits heated to high temperatures are present. This indicates that engine oil can induce pre-ignition. Furthermore, the effect of water vapor on ignition delay was investigated. Finally, it was confirmed that incorporating corrections for molecules possessing kinetic energy deviating from the Maxwell distribution under low-temperature, high-pressure conditions into the reaction rate calculation improves the prediction accuracy of autoignition around 800 K.

Moriyoshi, Yasuo, Yamane, Taichi, Wang, Zhiyuan, Kuboyama, Tatsuya

Optimizing Coil Structural Parameters to Enhance the Sensitivity of Wear Particle Sensor

2026-01-5033

5/14/2026

If wear particles generated during the operation of automobile engines are not monitored in time, they will contaminate the lubricating oil, leading to system failures or even accidents. Therefore, real-time wear particle monitoring is crucial for the stable operation of engines. Among mainstream wear particle monitoring sensors, the three-coil inductive sensor demonstrates significant application potential due to its ability to distinguish wear particle materials and strong resistance to environmental interference. However, its insufficient sensitivity to small-diameter wear particles limits further performance improvement. This paper takes the three-coil inductive wear particle monitoring sensor as the research object. First, a mathematical model of the sensor’s operation is established based on the law of electromagnetic induction, clarifying the relationship between structural parameters (such as channel radius, turns, coil spacing, and length) and the peak induced voltage. Subsequently, Multiphysics simulation software is employed to quantitatively analyze the influence of each structural parameter on the induced voltage, identifying directions for parameter optimization. Furthermore, orthogonal experiments are conducted to optimize discrete parameters, determining optimal levels for key parameters such as channel radius and coil spacing. Then, the simulated annealing algorithm is applied to achieve precise optimization of continuous parameters, ultimately obtaining the optimal combination of coil structural parameters. Experimental validation based on the optimized parameters shows that the peak-to-peak induced voltage for 1000 μm wear particles measured by the sensor optimized with the simulated annealing algorithm reaches 2.43 V, which is approximately 41 times higher than the 0.06 V observed before optimization. Additionally, the optimization effect of the simulated annealing algorithm further improves by 38.86% compared to the orthogonal experiment. In addition, experimental tests were also carried out on small-diameter abrasive particles of 100 μm, with the peak-to-peak value of the induced voltage reaching 0.38 V. The results confirm that this coil structural parameter optimization method effectively enhances the sensor’s sensitivity to small-diameter wear particles, providing a theoretical basis and technical support for the structural design and performance improvement of three-coil inductive wear particle monitoring sensors.

Yin, Hao, Zhao, Lijun, Shen, Yitao

Synthetic Rubber Hot Oil Resistant, High Swell 45 - 55

AMS3222J (Current)

4/28/2026

This specification covers a synthetic rubber in the form of sheet, strip, tubing, extrusions, and molded shapes. This specification should not be used for molded rings, compression seals, O-ring cords, and molded in place gaskets for aeronautical and aerospace applications without complete consideration of the end use prior to the selection this material.

AMS CE Elastomers Committee

Experimental Investigation Wear of the Power Cell Assembly of an Internal Combustion Engine Operated with Ethanol Through Vibration and Oil Analysis

2026-01-0352

4/7/2026

The durability test is an experimental test widely used in the automotive industry to verify the ability of an engine to withstand all operating conditions throughout its useful life. The test is performed on a dynamometric bench that subjects the engine to specific operating cycles. The objective of this study was to monitoring the level of wear of the power cell assembly and the performance of the engine operated with ethanol during the durability test. Wear monitoring was performed through the application of vibration analysis and lubricating oil analysis techniques. The results showed that the level of wear and performance of the engine after the durability test were considered satisfactory. Compared to durability tests previously conducted without monitoring, the analysis of wear metals in the lubricating oil and oil properties, combined with vibration analysis throughout the durability test, allowed for safe testing with a shorter total test time, optimized technical downtime and reduced wear on engine components. The application of vibration analysis and lubricating oil analysis techniques was important in monitoring wear and allowed the complete completion of the test.

Santana, Claudio Marcio

Physics-Based Simulation for Sustainable Fuels Part 2.1: Inter-Ring Pressure Measurements and 2D/3D Ring Dynamics Analysis across Multiple Engine Platforms – Light Vehicle

2026-01-0281

4/7/2026

The growing demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. The first part of this publication series highlights the significance of 2D simulation as a crucial and computationally efficient tool for the precise development of hydrogen Power Cylinder Units. This approach demonstrates predictive capability proofed through engine tests, achieving a reduction in lube oil consumption by 5 g/h during high-load operations, alongside a 28% decrease in blow-by and an 11% reduction in hydrogen flow to the crankcase. To provide deeper insights into the complexities identified in Part 1, this study employs inter-ring pressure measurements across various engine types and configurations, including light vehicles, heavy-duty trucks, and large-bore applications, covering a broad range of engine displacements from 2 to almost 100 liters. This investigation in Part 2.1 focuses on understanding the cyclic variations and mechanisms that lead to oil emissions during low-load operations at a light vehicle, while Part 2.2 focuses on upper compression ring instabilities, cyclic variation in a heavy-duty engine and as well as the factors contributing to irregular combustion phenomena within a large bore engine. Complementing predictive 2D simulations and inter-ring pressure measurements, targeted 3D analyses are performed for capturing three-dimensional effects such as bore distortion and ring conformability. These analyses yield valuable insights into oil transport mechanisms that can contribute to irregular combustion. Part 3 of this publication series will concentrate on 3D oil transport simulations and optimization, including predictions of absolute lube oil consumption ranges of the hydrogen engine discussed in Part 1, while building on the valuable insights gained from the in-depth investigation of Part 2.

Moreira, Rui, Köser, Philipp, Rösch, Hannes, Ehnis, Holger

Physics-Based Simulation for Sustainable Fuels Part 2.2: Inter-Ring Pressure Measurements and 2D/3D Ring Dynamics Analysis across Multiple Engine Platforms – Heavy Duty and Large Bore

2026-01-0280

4/7/2026

The growing demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. The first part of this publication series highlights the significance of 2D simulation as a crucial and computationally efficient tool for the precise development of hydrogen Power Cylinder Units. This approach demonstrates predictive capability proofed through engine tests, achieving a reduction in lube oil consumption by 5 g/h during high-load operations, alongside a 28% decrease in blow-by and an 11% reduction in hydrogen flow to the crankcase. To provide deeper insights into the complexities identified in Part 1, this study employs inter-ring pressure measurements across various engine types and configurations, including light vehicles, heavy-duty trucks, and large-bore applications, covering a broad range of engine displacements from 2 to almost 100 liters. Part 2.1 focuses on understanding the cyclic variations and mechanisms that lead to oil emissions during low-load operations at a light vehicle, while this investigation in Part 2.2 focuses on upper compression ring instabilities, cyclic variation in a heavy-duty engine and as well as the factors contributing to irregular combustion phenomena at a large bore engine. Complementing predictive 2D simulations and inter-ring pressure measurements, targeted 3D analyses are performed for capturing three-dimensional effects such as bore distortion and ring conformability. These analyses yield valuable insights into oil transport mechanisms that can contribute to irregular combustion. Part 3 of this publication series will concentrate on 3D oil transport simulations and optimization, including predictions of absolute lube oil consumption ranges of the hydrogen engine discussed in Part 1, while building on the valuable insights gained from the in-depth investigation of Part 2.

Köser, Philipp, Moreira, Rui

Physics-Based Simulation for Sustainable Fuels Part 1: Simulation-Driven Hydrogen Engine Power Cylinder Unit Optimization and Experimental Confirmation

2026-01-0278

4/7/2026

The demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. However, these engines present specific risks, such as flammable crankcase gas accumulation from blow-by and irregular combustion resulting from oil transport into the combustion chamber. Addressing these challenges requires advanced simulation tools to optimize power-cylinder-unit performance, specifically piston ring and gas dynamics. This study demonstrates the success of physics-based 2D simulation for hydrogen PCU design optimization, focusing on blow-by reduction and control of gas-flow-driven oil transport. Unlike commercial codes with adjustment and fitting parameters, the 2D simulation code – developed by Massachusetts Institute of Technology and successfully applied by MAHLE over decades – is fundamentally physics-based, enabling direct predictive capability without empirical calibration. Leveraging the validated “Healthy PCU System” design methodology 2D ring and gas dynamics models guided component optimization across the entire operating map. Comprehensive engine testing on a hydrogen-fueled platform confirmed simulation predictions, achieving a 28% reduction in blow-by and elimination of reverse-flow-driven oil transport. The optimized PCU design demonstrated significant improvements in lube oil consumption, with reductions of 5 g/h during high-load operations directly addressing hydrogen engine safety and performance requirements. While 2D simulation delivers excellent trend accuracy and captures average system behavior, it cannot resolve three-dimensional effects - such as ring and bore distortion conformability or ring gap positioning and ring rotation phenomena – which are responsible for local oil emissions or irregular combustion. Complementary 3D simulation analysis, combined with detailed inter-ring pressure measurements, provides essential insights into these localized phenomena and real engine behavior, as demonstrated in Part 2 of this publication series. As a further step, 3D oil transport simulation and lube oil consumption range prediction will be conducted as Part 3 of this publication series. This publication series establishes 2D simulation as the essential, computationally efficient tool for precise and efficient PCU development, while confirming that 3D analysis and experimental inter-ring pressure measurements are necessary to fully understand complex ring-liner interactions across multiple engine platforms.

Köser, Philipp, Moreira, Rui, Deuß, Thomas, Morgado, Leonardo

Optimization of Engine Cooling System for Improved Fuel Efficiency and Vehicle Marketability

2026-01-0297

4/7/2026

Effective thermal management in internal combustion engines is essential for meeting increasingly stringent emissions regulations and achieving fuel efficiency improvements. This study introduces a novel and comprehensive approach to optimize engine thermal management by addressing key system components, including coolant circuit design, Integrated Thermal Management Module (ITM) control strategies, port-specific flow management, zero-flow operation techniques, and HVAC (Heating, Ventilation, and Air Conditioning) settings standardization. Unlike previously published works, this study focuses on reducing coolant circuit thermal mass to accelerate engine and component warm-up, refining ITM control logic through linear mapping and advanced signal filtering for precision, and enhancing zero-flow operation for minimizing lubricant oil dilution during start-up and reducing heat loss under low ambient conditions. Additional optimizations include port-specific adjustments and radiator flow distribution strategies to improve system responsiveness and fuel economy. Standardized HVAC configurations were implemented to ensure reproducibility across WLTP vehicle and bench testing scenarios. The methodology validated key improvements through rigorous testing on a newly developed engine platform and demonstrated scalability by successfully integrating these measures into vehicles designed to comply with EU7 regulations. Results indicate substantial gains in warm-up performance, coolant temperature control stability, energy efficiency, and regulatory compliance. Furthermore, these advancements underscore their practical application for automakers seeking novel solutions to meet evolving environmental standards and enhance market competitiveness. Overall, this study presents a set of scalable and widely applicable strategies for modern spark-ignition engines, supporting both new engine development and optimization of existing engines, while addressing global fuel-efficiency and emissions challenges effectively.

Lee, Changjoo, Lee, Kyumin, Kim, Seonyeong, Nam, Choonho, Yoo, Jihun

A New Analytical Method for Calculating Transient Lube Oil Consumption

2026-01-5018

3/6/2026

Oil consumption is a major concern for all engine manufacturers, both from an environmental and engine durability standpoint. Understanding how oil consumption is affected by key design parameters has traditionally been established during the validation phase of an engine development program using both steady-state and transient lube oil consumption (LOC) measurements. Cost and time pressures are driving this development to be performed virtually, where many more parameters can be assessed and understood prior to design verification testing. This paper presents a new analytical method that is capable of predicting transient phenomena of the ring pack that would not normally be captured by steady-state methods, providing a toolset that reduces engine development testing and cost and aid troubleshooting. Implemented in Realis1 RINGPAK, this new transient method has been validated against transient LOC measurements for a 2.0 L 4-cylinder GTDI engine. Different transient load/speed schedules are presented, including fuel shut-off cases, together with a comparison against corresponding steady-state solutions. This new analytical method uses transient 1D engine performance simulations and finite element thermal and structural calculations of the in-cylinder to provide boundary conditions for each transient. The thermal boundary conditions are derived using an FE-based tool that uses physical models and semi-empirical correlations suitable for accurate predictions at part- and full-load conditions experienced during a transient. Sensitivity analyses have also been performed to gain an understanding of what input parameters most influence dynamic behavior of the ring pack during each transient.

Bell, David, Zhang, Shasha, Shen, Cong, Tisch, Dan, Brezina, Michal, Huang, Yun

Influence of Lubrication Oil on Hydrogen Fuel-Share Combustion in a Conventional Medium-Speed Marine Diesel Engine

2026-01-5014

2/23/2026

Carbon-free fuels present a potential solution for achieving climate-neutral operation of marine engines. However, their availability is minimal at the moment, though a steady increase can be expected in the coming years. During this transition phase, engine concepts that offer conventional diesel operation and a partial blending of alternative fuels to substitute diesel become interesting. This can be achieved, for example, by blending hydrogen in the intake air of a diesel engine, known as hydrogen fuel-share. Due to the high reactivity of hydrogen, its use in engines is limited by abnormal combustion phenomena (e.g., pre-ignition, knocking combustion), which current research on pure gas engines has shown to be strongly promoted by lube oil reactivity. Building on these fundamental investigations, this paper examines the influence of lubricating oil on the combustion characteristics of a H2 fuel-share medium-speed diesel engine and quantifies the potential to increase the hydrogen share using a less reactive engine oil. For this purpose, single-cylinder engine tests were conducted and supported by 0D/1D simulations with GT-Power and Cantera. The engine was configured as a conventional medium-speed marine diesel, equipped with a hydrogen port fuel injection (PFI) system on the cylinder head. A thermally stable ester-based gas engine oil was used for reducing reactivity compared to a state-of-the-art mineral diesel engine oil. The results show reduced auto-ignition tendency during compression and a mitigation of backfire. An increase in average effective CO2 reduction of up to 17 percentage points is demonstrated, resulting in a total CO2 reduction of 39% on a standard load profile for main propulsion engines. These findings highlight that the choice of lubricating oil can play a key role in increasing the hydrogen share in H2 fuel-share diesel engines, thereby supporting the transition toward climate-neutral propulsion concepts.

Achenbach, Tobias, Meinert, Robert, Mahler, Kay, Kunkel, Christian, Rösler, Sebastian, Prager, Maximilian, Jaensch, Malte

Modelling and Analysis of Hypoid Gear Churning Loss in Rear Drive Axle: The Role of Oil Viscosity and Empirical Parameters

2026-26-0508

1/16/2026

This definitive study investigates the variation of churning losses occurring with hypoid ring and pinion gear sets and factors that determine energy dissipation in these mechanisms. An in-depth investigation confirms that viscosity is critical, particularly because of its significant temperature-dependent variations. Furthermore, the study rigorously analyzes the data's experimental parameters to examine churning losses. These losses result from the interaction between the rotating gears and the lubricating oil, contributing to notable inefficiencies in the overall drivetrain. A robust and highly effective model has been developed to address this issue comprehensively. It accounts for variable oil viscosity with temperature and integrates key empirical parameters that reflect observed behaviours in gear systems. The study employs a multidimensional approach to examine how oil density impacts hydrodynamic resistance, which is key to understanding lubricant flow under varying conditions. It also assesses how fluid fill levels in the gear housing affect lubrication effectiveness and influence energy losses. It further defines the relationship of oil volume with power losses, signifying its importance in improving gear performance. This developed simulation model will thus give a holistic understanding of fluid dynamics relating to energy dissipation within gear systems by analyzing how these variables interact with each other and kinematic viscosity. This level of detail gives a deeper insight into the mechanisms in operation, thereby fostering better methods in optimising churning losses. The results of this study demonstrate crucial practical implications for optimizing lubrication methods, enhancing gear housing designs, and selecting the most effective fluids for gear systems. This research strengthens current knowledge in the automotive engineering sector and drives the advancement of more efficient and eco-friendly drivetrain systems. Tackling real problems in engineering, this study bridges the divide between theoretical models and applications by equipping engineers with more advanced tools to enhance overall system performance and efficiency.

Khan, Aliya Javid, Praveen, Abhinav, Kanagaraj, Pothiraj, Jain, Saurabh Kumar, AP, Baaheedharan

Exploring the Effects of Oil Cooler Deletion on Tractor Engine Operation

2026-26-0547

1/16/2026

An optimal engine lubrication system, encompassing engine oil and an oil cooler, is critical for thermal management and minimizing frictional losses. This system ensures adequate lubrication and cooling of engine components, thereby maintaining optimal performance. This study investigates the implications of oil cooler removal in a 45HP inline engine tractor. Various validation trials were conducted, including high ambient temperature tests under worst-case conditions, high coolant temperature scenarios, and a rigorous tractor killer test. In the latter, the tractor underwent 100 hours of operation on a PTO bench at maximum engine RPMs. Despite an observable increase in lubricant oil temperature during these tests, the tractor did not exhibit any component seizure or failure. The findings aim to determine whether the inclusion of an oil cooler is essential for the engine's operational reliability. This research offers valuable guidance for optimizing hardware selection and cost- effective design strategies in off-highway vehicles. Cost reduction remains a significant challenge for engine manufacturers, particularly for off-highway application vehicles, as they strive to ensure robust performance without compromising reliability.

Gupta, Deepak, Kumar, Pankaj, Singh, Manjinder, Singh, Gagandeep, Kumar, Munish, Singh, Harpreet, Singh, Maninder

Oil Channelization for EV Transmission

2026-26-0064

1/16/2026

Leakage of oil through breathers can be a serious concern in electric vehicle (EV) gearbox or transaxle units, especially due to the complexities presented by the small housing space and rotational components, which are running at relatively high speeds compared to conventional transmission units. Predicting the oil leakage from the transmission unit is another concern. Traditional methods are mostly centered on developing individual breather compartments, resulting in excess material usage, additional weight, and increased cost of manufacturing. To eliminate oil leakage through the air breather, the oil channelization technique used involves integrated oil deflection baffles, low-friction return channels, an oil accumulation cavity with cover, and strategically optimized airflow paths/vents. This design provides a number of benefits, such as increased gearbox reliability, minimized risk of component failure, and reduced maintenance needs, with all of these and a compact, cost-effective housing structure maintained. This paper presents a novel and compact way of oil channelization that has been created for the Electric vehicle powertrain housing and seeks to counter oil leakage, along with optimizing space, supported by simulation- based tools. In addition, the fluid simulation analysis was carried out and tested to develop a correlation with the real-life events. Using computational fluid dynamics (CFD) simulations and experimental validation with a prototyped transaxle housing, we demonstrate zero oil leakage in different running conditions with various grades and different speeds with varying oil quantity.

Ekshinge, Mahesh Shivaji, Agrawal, Devesh, Pandey, Ankit Kumar, Bhandari, Kiran Kamlakar

Research on Characterization Parameters of Main Bearing Wear Condition Based on Vibration Signals

2026-01-5003

1/15/2026

This study aims to investigate the influence of torque, rotational speed, lubricating oil temperature, and main bearing clearance on the vibration signals of diesel engine block surfaces, thereby establishing a foundation for diagnosing abnormal main bearing wear conditions using engine block surface vibration signals. An experimental test bench was constructed for a six-cylinder diesel engine to collect vibration signals under varying rotational speeds, torques, lubricant temperatures, and main bearing clearances. Frequency domain analysis and wavelet packet decomposition were then performed. The frequency domain analysis results indicate that the vibration signal amplitudes associated with abnormal main bearing wear are primarily concentrated below 5 kHz. Specifically, the energy in frequency bands below 1 kHz and around 2.5 kHz tends to increase with higher rotational speed, torque, and main bearing clearance, while the overall frequency domain amplitudes decrease with rising lubricant temperature. The wavelet packet decomposition results reveal that the energy in most decomposed frequency bands exhibits a positive correlation with rotational speed, torque, and main bearing clearance, but a negative correlation with lubricant temperature. Notably, the energy in wavelet packet bands 1–5 is significantly affected by rotational speed, bands 1, 3, 4, and 5 are notably influenced by torque, and bands 1 and 2 are strongly affected by main bearing clearance. The findings of this study provide a theoretical foundation and data support for the identification of abnormal wear states in the crankshaft–main bearing system.

Dong, Yiming, Hu, Yuping, Ji, Shaobo, Pan, Chi, Yue, Yuanhang, Liao, Guoliang

Application of Vibration and Lubricating Oil Analysis Techniques to Monitor the Performance and Wear of an Internal Combustion Engine in a Durability Test

2025-36-0025

12/18/2025

The durability test is an experimental test widely used in the automotive industry to verify the ability of an engine to withstand all operating conditions throughout its useful life. The test is performed on a dynamometric bench that subjects the engine to specific operating cycles. The objective of this study was to compare the level of wear of the power cell assembly and the performance of the engine operated with ethanol and gasoline during the durability test. Wear monitoring was performed through the application of vibration analysis and lubricating oil analysis techniques. The results showed that the level of wear and performance of the engine after the durability test were considered satisfactory. In general, the wear of the engine operated with ethanol was 5% higher than that of gasoline. The application of vibration analysis and lubricating oil analysis techniques was important in monitoring wear and allowed the complete completion of the test.

Marcio Santana, Claudio, Bruno Santana, Linicker Lopes, de Almeida, Helder Giostri Alves

Ca Additive and In-Cylinder Condition on Promotion of Abnormal Combustion in Supercharged SI Engine

2025-32-0004

11/3/2025

Recently, global warming is becoming seriously. In the field of internal combustion engine, the thermal efficiency has to improve in the practical use. One of the current trends with spark ignition engine (SI engine) is “downsizing” which is equipped supercharger with the downsized displacement. The downsizing engine is popular in the field of the SI engine. However, one of the problems is the abnormal combustion so called Low Speed Pre-Ignition (LSPI) [1]. The LSPI occurs the engine operation which is low speed and high load condition. It has to be avoided, because the SI engine is broken and the improvement of thermal efficiency is obstructed. A lot of researchers have been reported about the mechanism of LSPI [2, 3]. One of the sources of LSPI would be the lubricating oil droplets in cylinder. One of the methods to avoid LSPI, it has been adjusted the ingredients of oil additive in lubricating oil. The state of the art of lubricating oil standard has been established anti-LSPI performance. However, in the future, many kinds of fuels will be adapted to the SI engine on the point of CO2 emission. So, it would be needed that the mechanism of LSPI would be cleared essentially. It has been reported that the ingredients of oil additive strongly effect on the occurring the LSPI. There are two kinds of information in our previous research. First, the data show that frequency of abnormal combustion is 1/10 of frequency of scattering lubricating oil from the piston crown [4]. Second, autoignition timing of scattering lubricating oil is almost at ATDC, however, several autoignition advanced the timing for BTDC continuously. The results of previous our research have been mentioned about the relation lubricating oil droplet behavior in cylinder and abnormal combustion occurrence which include LSPI [5]. Here, this research focuses on the effect of Ca additive in lubricating oil on the frequency of abnormal combustion which is conducted to the LSPI.

kitano, Kaito, Tanaka, Junya

A Novel Approach to Enhance Compressor Life in Passenger Vehicle MAC Systems

2025-28-0409

10/30/2025

Compressor durability is a critical factor for ensuring the long-term reliability of Mobile Air Conditioning (MAC) systems in passenger vehicles. This study presents a software based strategy for enhancing compressor life using Smart Fully Automatic Temperature Control (FATC), requiring no additional hardware. The proposed approach leverages existing inputs from the FATC and Engine Management System (EMS) to intelligently manage compressor operation, with a focus on addressing challenges related to prolonged non-usage. In extended inactivity scenarios such as during cold weather, vehicle exportation, storage, or breakdowns, lubrication oil tends to settle in the compressor sump, leaving internal parts dry. Sudden reactivation at high engine speeds under such conditions can cause increased friction, wear and even compressor seizure. To mitigate this, an intelligent reactivation protocol has been developed and integrated into the Climate Control Module (CCM). This protocol continuously monitors parameters such as ambient and evaporator temperatures, solar load and engine RPM to detect extended inactivity. Upon detection, it initiates a controlled compressor activation sequence involving short duration clutch engagement cycles, allowing gradual lubrication and preventing mechanical stress. The strategy includes a multivariable detection framework and dynamic threshold adaptation that tailors activation logic to real-time environmental and operational conditions. A Smart transition mechanism ensures smooth switching between safe and regular operation modes. Preliminary testing shows that this method effectively minimizes dry starts, reduces mechanical wear and supports long term compressor health. The proposed strategy offers a cost effective and robust solution for improving compressor durability, lowering maintenance costs and enhancing user satisfaction.

Deshmukh, Ganesh, Chotaliya, Bhavy, Kulkarni, Shridhar, KHAIRE, DATTATRAY, Jaybhay, Sambhaji, Joshi, Gaurav, Shah, Geet

Rubber: Fluorosilicone (FVMQ) High Temperature Fuel and Oil Resistant For Seals In Fuel Systems and Specific Engine Oil Systems

AMS7273D (Current)

10/24/2025

This specification covers a fluorosilicone (FVMQ) rubber in the form of molded rings.

AMS CE Elastomers Committee

Impact of Oil Composition on Pre-Ignition in a Hydrogen Engine

04-18-03-0018

10/10/2025

Pre-ignition (PI) is a common issue in internal combustion engines (ICE) with spark ignition. While the various causes have been identified with conventional fuels (such as gasoline or gasoline blends), the causes with hydrogen in ICE are not yet fully understood. This article presents the results of investigations into the influence of seven different lubricating oils on PI in a single-cylinder hydrogen research engine. The variation of two different parameters at two engine speeds were investigated: load and air/fuel mixture. For both variations, the tests start at the same conditions and run until the operating limit of the engine is reached (peak firing pressure, or maximum intake manifold pressure). The PI and knocking PI are investigated, while classifying them according to the peak cylinder pressure. It has been observed that enleanment above λ = 2.4 can lead to higher PI rates, while simultaneously reducing the knocking PI. During the load sweep at 2000 1/min, the highest achievable load among all the oils ranged from IMEP = 19–21 bar, while at 4000 1/min, it ranged from IMEP = 12–15 bar. The performance of the oils showed significantly more disparity at the elevated engine speed. While the impact of different lubricating oils on gasoline engines is rather limited, the outcome of this experiment indicates that in the case of hydrogen engines, oils can have a significant impact on PI. In addition to the oil formulation, different viscosities were also investigated. A lower relative calcium content leads to a much higher PI rate, a lower relative calcium content combined with a higher viscosity did not impact the PI rate. The base oil composition came second in terms of PI influence. The sulfated ash content did not show differences in terms of PI rate. In contrast to gasoline engines, the PI tendency increases with increasing engine speed.

Pehlivanlar, Benjamin, Torkler, Michael, Fischer, Marcus, Göbel, Christoph, Pischinger, Stefan, Maulbetsch, Theo, Nübling, Fritz, Neumann, Stephan

Experimental Study of the Lubricating Oil Impact on the Unsteady Performance of an Automotive Turbocharger

2025-24-0078

9/7/2025

Turbocharging technique is a key technology for the development of hydrogen engines, allowing high lambda values to reach low NOx emissions. In ultra-lean mixture conditions, the thermal management of the lubricating oil and its cold condition becomes a crucial aspect that cannot be neglected. Accordingly, the impact of different lubricating oils and different lubricant thermal conditions is highlighted referring to the performance of a turbocharging system for automotive application. To this aim, an experimental campaign is conducted at the test bench for components of propulsion systems of the University of Genoa. Tests are performed on a turbocharger equipped with a variable geometry turbine under both steady and unsteady flow conditions, considering different positions of the turbine regulating device. A 4-cylinder engine head was coupled to the turbocharger in order to reproduce the pulsating flow related to the opening and closing of the engine valves. The influence of the lubricants on the assessment of turbine thermo-mechanical efficiency is analyzed under steady flow conditions considering different lubricating oils. The study reports the effects of the oil temperature on instantaneous turbine power and turbocharger efficiency under unsteady flow conditions. This analysis aims to provide a comprehensive understanding of turbocharger performance during the engine warm-up phase. The effects of heat transfer between turbocharger components are taken into account, along with the impact of different oil temperatures on friction losses and their effects on the instantaneous rotational speed of the turbocharger. The aim of this work is to provide valuable information on the actual performance of the turbocharger under unsteady flow condition with reference to the impact of the lubricating oil characteristic on the boost pressure provided to the engine.

Marelli, Silvia, Usai, Vittorio, Cordalonga, Carla

A Study on Sensitive Spots in Hydrogen Engines

2025-24-0059

9/7/2025

Premature self-ignitions in hydrogen internal combustion engines have been associated with the presence of hot spots. However, local increases in charge reactivity may be triggered not only by elevated temperatures but also by composition inhomogeneities. Such non-uniformities, in addition to imperfect mixing (e.g., in the case of direct hydrogen injection), may result from external contamination by more reactive components, such as lubricant oil. The present study aims to shed light on the mechanism through which lubricant oil contamination leads to the formation of sensitive spots, by analysing the behaviour of an isolated droplet suspended in a hydrogen/air environment. The “HyLube” chemical kinetic mechanism was employed to reproduce the chemical behaviour of lubricant oil, as it was specifically developed for this purpose. A one-dimensional numerical model was used to simulate the heating, vaporization, and combustion of the droplet. Zero-dimensional simulations were also performed using the open-source code Cantera (vers. 3.0.1) to better asses the effects of contamination. The impact of key operating conditions – such as ambient temperature, pressure, and composition, as well as droplet temperature and size – was investigated. The temporal evolution of selected variables, including the calculated instantaneous local charge reactivity, was analysed to characterise the fundamental mechanisms through which lubricant oil alters the charge reactivity and promotes early flame development within the combustion chamber of hydrogen-fuelled engines. The results contribute to a better understanding of how pre-ignition may occur due to lubricant oil contamination.

Distaso, Elia, Baloch, Daniyal Altaf, Amirante, Riccardo, Tamburrano, Paolo

Visualization Analysis of Hydrogen Combustion Triggered by Non-Controlled Hotspots Using a Rapid Compression Expansion Machine

2025-24-0047

9/7/2025

Research on hydrogen-fueled internal combustion engines has gained growing attention as a carbon-neutral solution to reducing emissions in the transport sector. However, challenges remain, with the risk of abnormal combustion being one of the major criticalities. This paper aims to clarify the ignition process of a hydrogen-air mixture caused by lubricant oil droplets and soot deposition. To achieve this, high-speed imaging methods were applied with a Rapid Compression Expansion Machine under engine-like conditions. Direct imaging and OH* chemiluminescence were captured simultaneously on the engine head to visualize the ignition point and flame propagation. Different operating conditions were tested to evaluate the influence of lambda, intake pressure, and soot quantity on ignition occurrence. For each test bench configuration, ten successive tests were conducted to assess the probability of ignition. The presence of soot was ensured through a preliminary run with diesel injection. The presence of oil, instead, naturally increases inside the cylinder with each successive run due to the functioning of the modified test bench’s lubricating system. Three typologies of combustion modes were identified – late, weak, and early ignition. These are analyzed using chamber dynamic pressure and heat release rate trends, along with optical analysis. Direct imaging enables the identification of the droplet responsible for ignition, and OH* chemiluminescence allows visualization of the flame front propagation from the ignition point. As expected, an increase in intake pressure, a decrease in lambda, and the presence of soot all raise the probability of early ignition, with lambda having the most significant effect.

Tempesti, Claretta, Yukitani, Takumi, Horibe, Naoto, Romani, Luca, Ferrara, Giovanni, Kawanabe, Hiroshi

Numerical Study of Mixing, Combustion and NOx Emissions in a DI High Performance Hydrogen Engine Operated at Stoichiometry

2025-24-0010

9/7/2025

The roadmap towards carbon neutrality by 2050 makes necessary drastic reduction of road vehicle tailpipe carbon emissions. One viable approach to reach the abatement of carbon monoxide and dioxide is to fuel internal combustion engines (ICEs) with hydrogen. The burning of a hydrogen-air mixture inside the combustion chamber reduces to minimal amount the production of carbon emissions and particulate matter that are only produced by the presence of lubricant oil. However, the high temperatures reached by the end-gases promote the formation of nitrogen oxides. In high-performance ICEs, the pursuit for high-specific power by means of the adoption of stoichiometric mixtures is hindered by the need to reduce NOx - as this pollutant drastically drops when moving towards ultra-lean mixtures. The paper aims to present a CFD-3D framework to simulate the full engine-cycle of a high-performance Spark-Ignited (SI) Direct-Injection (DI) ICE fuelled at stoichiometric conditions. The methodology is validated thanks to experimental data collected at part-load condition (2000 rpm and 4.5 IMEPH) changing the injection timing and at full-load operation (6000 rpm and 24 bar IMEPH). The experimental measurements of nitrogen oxides at the part load conditions are compared with the outcome of the CFD. In particular, the most delayed injection case is compared with the most advanced one to give an overview of the effect of the stratification of the mixture in the formation of the analysed pollutants. Furthermore, the validated model is employed to predict amount of NOx generated in the most demanding condition (6000 rpm) to better understand the influence of temperature, pressure and mixture composition on the NOx production pathways.

Baudone, Antonio Denny, Marini, Alessandro, Sfriso, Stefano, Falcinelli, Francesco, Mortellaro, Fabio, Tonelli, Roberto, Breda, Sebastiano

Specification for Aero and Aero-Derived Gas Turbine Engine Lubricants

AS5780E (Current)

7/17/2025

This specification defines basic physical, chemical, and performance limits for 5 cSt grades of gas turbine engine lubricating oils used in aero and aero-derived marine and industrial applications, along with standard test methods and requirements for laboratories performing them. It also defines the quality control requirements to assure batch conformance and materials traceability and the procedures to manage and communicate changes in oil formulation and brand. This specification invokes the Performance Review Institute (PRI) product qualification process. Requests for submittal information may be made to PRI at the address in 2.1.3, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by PRI. Additional tests and evaluations may be required by individual OEMs before an oil is approved for use in their equipment. Approval and/or certification for use of a specific gas turbine engine oil in aero and aero-derived marine and industrial applications is the responsibility of the individual OEMs and/or governmental authorities and is not implied by compliance with or qualification to this specification.

E-34 Propulsion Lubricants Committee

O-Ring Molded from AMS7274 Material

AS3570A (Current)

7/17/2025

This standard establishes the dimensional and visual quality requirements, lot requirements, and packaging and labeling requirements for O-rings molded from AMS7274 rubber. It shall be used for procurement purposes.

A-6C2 Seals Committee

Method for Externally Controlled Availability of Lubricating Oil in Internal Combustion Engines

2025-01-0302

7/2/2025

Reduced raw emissions from internal combustion engines (ICE) are a key requirement to reach future green-house-gas and pollutive emissions regulations. In parallel, to satisfy the need for increased engine efficiencies, the friction losses of ICEs gains attention. Measures to reduce parasitic drag inside the piston assembly such as reduced piston-ring pretension or thinner grade engine oils may increase oil ingress into the combustion chamber. The oil ingress is known to imply increased particle emissions directly counteracting the raw emission reduction target of engine development. To resolve this target conflict, the transport mechanisms of oil into the combustion chamber are the topic of current research. Specially developed research engines featuring a vertical optical window come with big potential to visualize the phenomena of the oil behavior inside the piston assembly group. Such ‘glass-liner’ engines play a pivotal role in identification and quantification of local and global phenomena and their correlating operating parameters. The objective of this study is to develop and investigate a novel approach facilitating active control over the amount of oil available in the piston group assembly under varying operating parameters. The mechanical incorporation into the engine relies on ports embedded into the cylinder wall. These ports facilitate accessing the ring-land areas to realize fluid flow out of the piston group assembly using either vacuum or compressed air. The system is investigated in both a ‘glass-liner’ as well as a thermodynamic engine. Optically, the amount of oil present at the piston surface as well as residual oil on the cylinder wall is evaluated. A reduction of up to 40 percent of the indicated LIF-intensity from the residual oil on the cylinder surface can be shown. Similar results from tailpipe measurements are also demonstrated.

Stark, Michael, Fellner, Felix, Härtl, Martin, Jaensch, Malte

Heavy-Duty Vehicle Lubricating Greases

J2695_202506 (Current)

6/30/2025

This SAE Recommended Practice was developed by SAE and the section “Standard Classification and Specification for Service Greases” cooperatively with ASTM and NLGI. It is intended to assist those concerned with the design of heavy-duty vehicle components and with the selection and marketing of greases for the lubrication of certain components on heavy-duty vehicles like trucks and buses. The information contained herein will be helpful in understanding the terms related to properties, designations, and service applications of heavy-duty vehicle greases.

Fuels and Lubricants TC 3 Driveline and Chassis Lubrication

Grease, Aircraft, General Purpose, Low Temperature Range, Lithium Thickened

AMS3052B (Current)

6/30/2025

This specification covers grease for use within an aircraft. It also defines the quality control requirements to assure batch conformance and materials traceability and the procedures to manage and communicate changes in the grease formulation and brand. This specification invokes the Performance Review Institute (PRI) product qualification process. Requests for submittal information may be made to the PRI at the address in 2.2, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by the PRI. Additional tests and evaluations may be required by individual equipment builders before a grease is approved for use in their equipment. Approval and/or certification for use of a specific grease in aero and aero-derived marine and industrial applications is the responsibility of the individual equipment builder and/or governmental authorities and is not implied by compliance with or qualification to this specification.

AMS M Aerospace Greases Committee

Aviation Lubricant Tribology Evaluator (ALTE) Method to Determine the Lubricating Capability of Gas Turbine Lubricants

ARP6255A (Current)

5/16/2025

Employing “ball-on-ring” philosophy, a nonrotating steel ball is held in a vertically mounted chuck and, using an applied load, is forced against an axially mounted steel rotating ring. The test ring is rotated at a fixed speed while being partially immersed in a lubricant reservoir. This maintains the ring in a wet condition and continuously transports a lubricating film of test fluid to the ball and ring interface. The diameter of the wear scar generated on the test ball is used as a measure of the fluid’s lubricating properties. The apparatus can be used by adjusting the operating conditions to reproduce two different wear mechanisms. Therefore, the ALTE can assess a lubricant’s performance in that regard. These mechanisms are described below.

E-34 Propulsion Lubricants Committee

Prediction of Pre-Ignition Borderline on Supercharged SI Engine by Livengood-Wu Integral

2024-32-0008

4/18/2025

The LSPI (Low Speed Pre-Ignition) is one of the consecutive abnormal combustion cycles of supercharged SI engine with direct injection fuel supply system [1]. The LSPI occurs when the engine is running at low speed and high load condition. It is important for the SI engine to control essentially with alternative fuel, e-fuel and hydrogen in the future. It is considered that the LSPI would be caused by the autoignition of the deposit, the lubricating oil from ring crevice, the lubricating oil from piston crown and so on [2, 3, 4, 5]. Among of these causes, this research focuses on the scattering lubricating oil from piston crown. The previous our research has reported on the two points. One is about the frequency and quantity of the lubricating oil scattering from piston crown [6]. Another is about the frequency of abnormal combustion by the engine test [7]. As the result, it has been cleared that the frequency of abnormal combustion is 1/10 of scattering frequency of the lubricating oil from piston crown. Moreover, it has been evaluated in-cylinder condition by the Livengood-Wu integral when the autoignition occurred. The LSPI would occur suddenly, continue several cycles and return to the normal combustion cycle again. However, it is difficult to find the borderline that the LSPI would occur or not for each engine and operating condition. This research will try to define the borderline of the occurring LSPI or not. The experimental data show the autoignition timing has three patterns. The autoignition timing advances from ATDC to BTDC when the consecutive abnormal combustion cycles proceed, it delays from BTDC to ATDC and all abnormal combustion cycles appear at ATDC. It is proposed that the borderline of LSPI is defined by the analysis of those autoignition with the Livengood-Wu integral.

Omori, Takaya, Tanaka, Junya

Used Motor Oil Regeneration Efficiency of Type X Fly Ash–Based Zeolite Alone and Combined with Other Adsorbents

04-18-03-0013

4/15/2025

This research article assesses the used motor oil’s (UMO) regeneration efficiency of a synthetic type X zeolite (siliceous fly ash–based) alone and combined with other adsorbents (composite adsorbents), namely activated carbon, bentonite, and acid-activated bentonite from Goshica’s (Kosovo) region. The UMO treated with the regenerating mixes has run about 20,000 km. Parameters including density, kinematic viscosity, viscosity index, pour point, and sulfur content were measured in the untreated and treated UMO and compared to those of the reference oil with additives of type SAE 5W-30. All regeneration mixes showed good regeneration efficiency, restoring the UMO’s parameters to almost the original ones of the reference oil with additives (SAE 5W-30). Only the zeolite alone could significantly reduce the sulfur content (removal efficiency 60%). This method deserves further investigation and with some improvements, it can be established as a reliable regeneration method for some UMO.

Korpa, Arjan, Dervishi, Sara, Gecaj, Diana, Shahu, Kristi, Shehu, Alma, Nuro, Aurel

Engine Crankcase, Oil Pan and Lube System Multiphase CFD Analysis for Predicting Oil Aeration

2025-01-8364

4/1/2025

This paper explains transient, computationally rigorous, three-dimensional and one-dimensional multiphase CFD analysis of engine oil drainback system and lubrication system for predicting aeration. Aeration of engine oil is an important factor as it affects working of Hydraulic Lash Adjusters, bearings performance and it reduces lube system pressure itself which is detrimental for the entire engine. In this work specifically effect of engine tilting on lube oil aeration is presented. When engine is tilted, crankshaft and connecting rod/s are dipped in to oil, which creates air bubbles. These air bubbles travel to lube pump and then to the engine lube system. Therefore, it is essential to model aeration in Engine crankcase, Oil pan and Lube system for the purpose of predicting oil pressure reduction in lube system. The problem under consideration is spread over a bigger zone, involves rotating and translating components, passage’s dimensions are varying from microns to meters and involves multiphase physics. Therefore, it becomes a formidable task to accurately predict lube oil aeration using simulation. In current work, an approach is developed which involves use of multiple simulation tools for handling all the intricacies of geometries and complications of physics. Number of unique ideas have been developed in order to handle multiphase, moving boundaries, high fidelity CFD solution. The predicted lube system oil rifle pressure is compared with test data and the results are found to be within engineering accuracy. The developed procedure can be used to analyze effect of parts’ design change on aeration during engine design and development. The procedure can also be extended for modeling effect of vehicle dynamics on oil aeration.

Tawar, Ranjit Ramchandra, Bedekar, Sanjeev

Intebrake 3-D CFD Transient Simulation Studies for Predicting Flow Performance

2025-01-8362

4/1/2025

This paper presents transient, complex, moving mesh, 3-D CFD analysis of an intebrake lubrication oil circuit for predicting flow performance. Intebrake is a mechanism for improving braking performance during over speeding conditions. The mechanism briefly opens the exhaust valve at the end of a compression stroke with a small valve lift and releases the compressed gases, thereby helping in quick application of the brake. There is no fueling during the process and hence, no combustion induced pressure rise which helps in quick application of the brake. During the intebrake operation, opening of the exhaust valve is achieved by using a complex lube oil circuit inside the exhaust rocker lever. The intebrake lube oil circuit consists of various spring-operated valves with micro-sized clearances, high oil pressure generation up to ~ 250 bar, 3-D movement of the mechanism components, and it is a transient operation. The 3-D movement consists of simultaneous rotational and translational motions with dynamic motions due to net force balance between spring and fluid forces. All these factors make the simulation an absolute need as testing is extremely costly and difficult due to tight space constraints around the mechanism. The 3-D CFD model with automatic intebrake ON and OFF operations makes dynamic mesh motion more complex. In the current work, 3-D CFD simulation approach is developed which can model the intebrake operation by considering dynamic mesh, small clearances, and oil compressibility effects. The predicted intebrake lube system oil pressure is compared with transient, crank angle based test data and the results are found to be in good correlation. This approach has helped in better understanding of the intebrake response to variation of different design parameters and resolving field failures. After a single cylinder intebrake model validation, it has been extended to modeling 6-cylinders and integrated with engine 3-D CFD lube system as well.

Tawar, Ranjit Ramchandra, Pasunurthi, Shyam Sundar, Bedekar, Sanjeev, Ranganathan, Raj

Reduced Order Model for Viscosity and Mass Density Sensing by A U-Shaped Wire

2025-01-8472

4/1/2025

This paper focuses on the basic principle of measuring viscosity and density with U-shaped tungsten wire sensor, and develops a model for measuring liquid viscosity and density with the help of oscillating ball model. Firstly, the working mechanism of the wire resonator is deeply analyzed. Then, by reducing the order of the fluid dynamic function, a simplified model is established for measuring the viscosity and density of liquid with U-shaped tungsten resonator. The experimental results show that the maximum error of viscosity is 7.22% and the average error is 2.81% when the viscosity ranges from 4.526mPa.s to 62.01mPa.s. In the range of 0.8486g/cm3 to 0.8711g/cm3, the maximum density error is 7.00% and the average density error is 1.89%. In summary, the simplified model proposed in this paper can accurately measure the viscosity and density of liquids.

Shan, Baoquan, Shen, Yitao, Yang, Jianguo, Zhang, Zhaoying, Wu, Dehong, Zhao, Yingke

Effects of Lubricating Oil Consumption and Operation Duration on CO ₂ Accumulation and Efficiency in an Argon Power Cycle Hydrogen-Fueled Engine

2025-01-8436

4/1/2025

The trend of internal combustion engines is reducing or eliminating carbon emissions and improve the overall efficiency. The Argon Power Cycle hydrogen-fueled engine can specifically improve the thermal efficiency by employing argon as the working substance. At the same time, due to the utilization of hydrogen and oxygen, the combustion of the fuel in Argon Power Cycle hydrogen-fueled engines produces zero carbon emissions or NOx emissions. However, during engine operation, lubricating oil consumption can still generate CO2 and becomes the only source for carbon emissions. Furthermore, the accumulation of CO2 under closed cycle will impede the condensation recovery of argon and reduce the efficiency and power. In this study, a closed cycle model of Argon Power Cycle hydrogen-fueled engine was constructed, in which argon is recycled by condensation instead of being charged like air in an open cycle model. Effects of lubricating oil consumption and operation duration on CO2 accumulation, temperature and pressure at each engine process, combustion characteristics, net indicated thermal efficiency, and net indicated mean effective pressure were numerically investigated. The results show that the molar ratio of CO2 in the intake gas (CO2 fraction) grows with the increase of both lubricating oil consumption and operation duration, resulting in higher pressures during exhaust and intake processes. In addition, the peak combustion temperature (Tmax) decreases and thus the percentage of heat transfer loss decreases. However, the larger increment in the percentage of exhaust loss results in lower net indicated thermal efficiency and thus lower net indicated mean effective pressure. For 50 minutes of operation at lubricating oil consumption = 1.5 g/h, the CO2 fraction reaches 9.9%, with net indicated thermal efficiency decreasing from 53.7% to 50.4% and net indicated mean effective pressure decreasing from 0.53 MPa to 0.50 MPa. As a contrast, at lubricating oil consumption = 0.15 g/h, the CO2 fraction is 1.1%, with net indicated thermal efficiency = 53.4% and net indicated mean effective pressure = 0.52 MPa. Therefore, when the lubricating oil consumption is reduced to 0.15 g/h or carbon-free lubricating oil is used, the effect of lubricating oil consumption on Argon Power Cycle engine’s operation duration and efficiency will be effectively reduced or eliminated. This work will provide a reference for the development of the closed system of Argon Power Cycle such as lubricating oil consumption control strategy and CO2 capture device design.

Wang, Chenxu, Li, Mo, SU, Xiang, Deng, Jun, Tian, Tian, Li, Liguang

Development of Dehydrated Kusum Oil as a Potential Bio-Lubricant

2025-01-8312

4/1/2025

Depletion of petroleum crude oil and its environmental impacts challenge future generations. Vegetable oils provide a sustainable alternative with benefits like anti-wear properties, biodegradability, and renewability. Kusum oil's ability to lower carbon emissions significantly and promote sustainable industrial practices highlights its potential as a viable green alternative. This research paper presents a comprehensive and comparative analysis of a sustainable, environmentally friendly bio-lubricant and nonedible vegetable oil like Kusum oil. Bio-lubricant is produced by transesterification followed by epoxidation, which is known as epoxidized kusum oil lubricant or dehydrated kusum oil (DKO). The process of epoxidation significantly enhances the properties of Kusum oil, making it a promising alternative to conventional lubricants. It is compared with a widely used conventional mineral oil lubricant like SAE10W40. DKO exhibits comparable density, viscosity index, pour point, and flash point with SAE10W40 and found satisfactory. Subsequently, FTIR (Fourier Transform Infrared Spectroscopy) and GC (Gas Chromatography) are also used to characterize the chemical composition of DKO, and the results are comparable with SAE10W40. By introducing epoxy groups into the unsaturated fatty acids of Kusum oil, epoxidation increases the oil's oxidative stability, making it more resistant to degradation at high temperatures, which is verified with the Thermo Gravimetric Analysis (TGA). It reveals that the bio-lubricant is thermally stable up to 250°C, with significant decomposition occurring between 250°C and 450°C. The epoxidized kusum oil with 0.2wt. % MWCNT significantly improves its anti-wear characteristics, leading to a reduction in wear volume when compared to both SAE10W40. This highlights its promise as a viable and eco-friendly substitute lubricant for mechanical uses. This comparison underscores the importance of epoxidized kusum oil bio-lubricant, and it provides a new direction for similar research and development in lubricants, aiming to balance performance with environmental responsibility.

Prabhakaran, J, Pali, Harveer Singh, Singh, Nishant K.

Machine Learning-Based Digital Twin for Optimizing Automotive Components

2025-01-8206

4/1/2025

This paper presents a Digital Twin approach based on Machine Learning (ML), aimed at creating software-based sensors to reduce the auxiliary devices of the vehicle and enabling predictive maintenance, thus reducing carbon footprint. The solution is applied to the electric Lubrication Oil Pump (eLOP), a crucial component within a vehicle's powertrain system. The proposed eLOP Digital Twin integrates ML-based sensors to estimate critical parameters such as temperature, pressure and flow rate, reducing the reliance on physical sensors and associated hardware. This approach minimizes manufacturing complexity and cost, enhancing energy efficiency during both production and operation. Furthermore, the Digital Twin facilitates predictive maintenance by continuously monitoring the component's performance, enabling early detection of potential failures and optimizing maintenance schedules. This leads to lower energy consumption and reduced emissions throughout the component's lifecycle. The Digital Twin architecture is constructed using a detailed simulation model of the eLOP, which is validated against empirical data to ensure high fidelity in replicating real-world behavior. The simulation model generates a comprehensive dataset capturing various operational scenarios, which is then used to train ML models for the estimation of physical quantities and the prediction of remaining useful life of the component. These predictive capabilities are crucial for vehicle-level applications that can significantly impact overall vehicle efficiency. Though the focus of this paper is on the eLOP, the methodology can be extended to other components and systems, demonstrating a scalable approach to the use of ML for optimizing vehicle performance, providing a pathway to more sustainable automotive design and operation.

Khan, Jalal, D'Alessandro, Stefano, Tramaglia, Federico, Fauda, Alessandro

A Comparative Study on the Working Efficiency of Journal Bearing Employing Different Micro-Textures

04-18-02-0011

2/19/2025

This study proposed the different micro-textures of the SC (square cylinder), SWS (square wedge shape), HS (hemispherical shape), and CR (cylindrical round) to improve the working efficiency of the journal bearing. A hydrodynamic lubrication model of the journal bearing under the impact of the changing dynamic loads is established to analyze the performance of micro-textures. The maximum oil film pressure and minimum frictional force in the journal bearing are selected as two evaluation indices. Some outstanding research results show that all the SC, SWS, HS, and CR added on the bearing surface improved the working efficiency of the journal bearing better than without the micro-textures. Moreover, the HS also improved the working efficiency of the journal bearing better than other structures of SC, SWS, and CR. To optimize the working efficiency of the journal bearing using HS, the dimension ltex and depth htex of HS should be selected and designed in a range of 3.6 < ltex ≤ 3.9 mm and 7.5 ≤ htex ≤ 10 μm, especially at ltex = 3.6 mm and htex = 10 μm. Research results not only provide a detailed assessment of the lubrication efficiency of different micro-textures but also find a new structure of HS with their optimal parameters to further improve the working efficiency of the journal bearings.

Song, Fengxiang, Nguyen, Vanliem, Liu, Yaxi

A Critical Evaluation of Laboratory Test Methods Used to Assess Coke Formation Tendency in Synthetic Lubricants

2025-28-0036

2/7/2025

Lubricant oil in combustion engines undergoes thermal degradation under high temperatures and forms solid deposits. These deposits, called coke, are insidious, black, and carbonaceous solids. To mitigate the problems associated with oil coking, an effective testing methodology must be developed to characterize the coke formation qualitatively and quantitatively. Previously, testing methodologies have been developed to measure coking tendency however some of the international standards such as the SAE ARP 6166 use visual inspection methods to assess coke. Such methods are unsuitable for advanced research as they are prone to error in human judgment. This paper intends to bridge this gap and discusses test methodologies that can measure Coke quantitatively and qualitatively. Coke formation has been studied using different laboratory methods such as static immersion, thin film oxidation, and dynamic spray tests to replicate the various conditions. In a static immersion test, a metal sample is submerged in oil and heated to form coke. In the thin film oxidation test, an oil drop is deposited and heated over the metal sample. In the case of dynamic test measurement, the oil is sprayed over a heated metal sample. The lubricant coke has been characterized using its thickness, mass, and chemical composition. One of the key challenges associated with accurate coke measurement is the brittle nature of coke. It has been concluded that the thin film oxidation test method is the fastest method to assess the coke deposit, followed by the static immersion test and the dynamic test method.

Jeyaseelan, Thangaraja, S, Shanmugasundaram, Bansal, Lalit, Negi, Ashish, Koka, Tirumala Rao, Das, Arnab

Improving the Carbon Footprint of Long-Haul Trucks Running on First-Generation Biodiesel

2025-01-5007

1/27/2025

Lowering carbon emissions from road-based transport is required to achieve climate targets. In addition to passenger cars, long-haul trucks contribute more than one-third of on-road generated carbon emissions. Therefore, this sector has great potential to reduce such emissions. Numerous options including electrified drivetrains are possible. Nevertheless, the existing fleet of trucks powered by conventional diesel engines also needs to be addressed. Additionally, a ramp-up of green electricity and charging infrastructure is required to ensure carbon-neutral and reliable transport. Heavy-duty diesel engines are typically suitable for use with first-generation biofuels. However, operational restrictions, such as shorter oil drain intervals are mandatory for users. In the case at hand, the oil change was mandatory after only 30,000 km when pure biodiesel (B100) was used instead of 120,000 km when operating on conventional, mineral oil-based diesel. These boundaries counter efforts to lower carbon emissions because operators are reluctant to adopt such fuels to mitigate operational constraints, and the disposal of an additional amount of lubricating oil results in the release of avoidable carbon emissions. This work describes a trial conducted to extend the oil drain intervals of long-haul trucks. The oil condition of the four vehicles running on biodiesel was closely monitored by oil analysis. The usual parameters for oil analysis, such as viscosity, wear metals, water content, fuel dilution, oil oxidation, and nitration, were monitored in this study. The study was concluded when an oil lifetime of 90,000 km was reached and confirmed by a second run. The obtained data were compared to those of a reference vehicle running on conventional diesel fuel. The conclusion was that no adverse effects on moving engine parts were present at each stage of drawing samples of oil and at the end (completion) of tests. The possible threefold increase in the oil drain interval helps reduce CO2 emissions, thus aiding in achieving climate goals.

Rohbogner, Christoph J., Heine, Carsten

Analysis of the Characteristics of Hybrid Vehicles and Low-Viscosity Lubricating Oil Based on Real Road Tests in Four Extreme Environments

04-18-02-0009

1/7/2025

As countries around the world attach more importance to carbon emissions and more stringent requirements are put forward for vehicle emissions, hybrid vehicles, which can significantly reduce emissions compared with traditional fuel vehicles, as well as low-viscosity lubricating oil, have become significant trends in the industry. In this article, a total of nine vehicles of 48 V mild-hybrid models and full-hybrid models are tested. Using three kinds of low-viscosity lubricating oil and driving a total of 120,000 km in environments with low temperature, high humidity, high temperature, or high altitude, the engines are then disassembled and scored. The effects of the four extreme environments on the engine starts–stops, ignition advance angle, engine power, state of charge (SOC), acceleration performance, and oil consumption characteristics of hybrid vehicles are studied; the oxidation characteristics and iron content change characteristics of low-viscosity lubricating oil are analyzed; and how lubricating oil protects the engine in durability tests are verified. According to the test results, in the low-temperature environment, for full-hybrid models, the number of engine starts–stops and the running time are significantly increased, while the SOC is generally high. In the high-temperature environment, for full-hybrid models, the ignition advance angle of the engine is reduced, which inhibits the risk of pre-ignition; the characteristics of the SOC are similar to those in the high-humidity and standard-temperature WLTC working conditions; the oxidation rate of lubricating oil has almost no effect on full-hybrid models; for mild-hybrid models, oil is prone to oxidation and decay. In the high-humidity environment, the oil consumption rate deteriorates with the increase in relative humidity under the same load and engine speed, and the accumulation rate of iron content in oil increases compared with that in the high-temperature and high-altitude environments. In the high-altitude environment, with the increase in altitude, the engine power of full-hybrid models decreases at the same engine speed, resulting in a decrease in the engine’s charging efficiency to the battery, so that the battery level could not be relatively stable. The acceleration performance of both hybrid models decreases significantly with an increase in altitude. After the engines are disassembled, it is found out that with the protection of low-viscosity lubricating oil, the wear of engine parts is very small, and the deposit control is good.

Zhu, Gezhengting, Hu, Hua, Pan, Jinchong, Luo, Yitao, Hua, Lun, Jiao, Yan, Jiang, Jiandi, Shao, Heng, Xu, Zhengxin, Yan, Jingfeng, Wei, Guangyuan, Zhang, Heng

A Quasi-Two-Dimensional Approach in Laminar Flow of Lubricating Oil and Grease

04-18-02-0007

12/9/2024

The overarching objective of the present study is to apply a quasi-two-dimensional approach to analyze the laminar flow of lubricating oil. Lubricating oils are non-Newtonian by nature. For these types of oils, the Sisko fluid model is the most suitable model of the nonlinear stress–strain relationship for these types of oils. It is hoped that by omitting the dependence of flow quantities in one direction, more qualitative information can be obtained on the characteristics of the purely three-dimensional boundary layer flow of lubricating oils. Some of the most familiar flow geometries discussed are steady flow over a flat plate, a corner of a wedge, and a stagnation region; steady flow in a convergent and divergent channel; and impulsively started flow over an infinite flat plate and semi-infinite flat plate. The governing equations of all flow geometries are transformed into nonlinear ordinary differential equations (ODE) using the free parameter transformation. The results are discussed briefly in the graphical presentation.

Patel, Manisha, Bariya, H.G.

Development of Lubricants Using Re-Refined Base Stocks—An Effort toward Circular Economy

04-18-02-0008

12/6/2024

Re-refining of used lubricating oil is an economically attractive and effective recycling method that contributes significantly to resource conservation and environmental protection. The effective re-refining process of used lubricating oil undergoes thorough purification to remove contaminants and to produce high yield and good quality base oil suitable for reuse in lubricant formulation. Used lubricating oils have various hazardous materials, these can be processed with safe and efficient methods required to recover high-quality base oil products. Typically, used lubricating oil is a mixture of various types of additives, base oils, and viscometric grades as per the different types automotive and industrial applications. Re-refined base oils can be re-used to produce lubricants such as industrial and automotive lubricants like passenger car motor oils, transmission fluids, hydraulic oils, and gear oils. API classified base oils into two categories namely mineral base oils API Group I–III and synthetic base oils Group IV–V. Re-refined base oils meeting API Group I and II quality standards are mostly produced by re-refiners. In this article, the author has evaluated lubricating oils: gear oil meeting API GL4 specifications based on 25% re-refined base oil to assess the performance of these lubricants in comparison to conventional base oil-based lubricants. This study includes physicochemical tests, lab performance tests (rust, corrosion, shear stability, and oxidation), and tribological performance tests, i.e., weld load, wear scar diameter, and friction performance by MTM was also evaluated. Test results show similar performance in terms of low temperature, oxidation, and friction performance in 25% re-refined base oil-based lubricant with respect to conventional base oil-based products.

Maloth, Swamy, Joshi, Ratnadeep S., Mishra, Gopal Swaroop, Samant, Nagesh N., Bhadhavath, Sanker, Seth, Sarita, Bhardwaj, Anil, Paul, Subinoy, Arora, Ajay Kumar, Maheshwari, Mukul

Towards Robust Hydrogen Combustion: Precise Lube Oil Consumption Measurement as an Enabler for Tackling Pre-Ignition

2024-01-4290

11/5/2024

The use of carbon-free fuels, such as ammonia or hydrogen, or at least carbon neutral fuels, such as green methane or methanol is one of the most important paths in the development of low-carbon internal combustion engines (ICE). Especially for large, heavy-duty engines, this is a promising route, as replacing them with battery electric or fuel cell drives poses even greater challenges, at least for the time being. For some applications or areas of the world, small ICEs for trucks, passenger cars or off-road vehicles, operated with alternative fuels will still remain the means of choice. One of the biggest challenges in the development of hydrogen combustion engines is achieving high compression ratios and mean effective pressures due to combustion anomalies, caused by the low ignition delay and broad flammability limit of hydrogen. Oil droplets are considered to be one of the main triggers for pre-ignition and knocking. This paper will give a brief introduction, showing the results of studies on the contribution of oil droplets to combustion anomalies. In this study, oil droplets were artificially injected into the intake manifold in order to trigger pre-ignition. As the correlation between these two phenomena was clearly seen, the second part of the paper will focus on the measurement of oil consumption, which is an important way to combat combustion anomalies. To this end, three innovative measurement technologies were compared. The first method is based on the balance of carbon entering and leaving the combustion chamber. The second method is based on the use of deuterium, which is added to the engine oil as a tracer. The third method is based on measuring the unburnt portion of hydrocarbons with a time-of-flight mass spectrometer (TOF-MS). All methods provide very similar qualitative results. The deuterium and the carbon method show very good quantitative congruence as well and are therefore considered to be very precise and. The respective advantages and disadvantages are shown in the discussion chapter. Additionally, measurement data will show the influence of the hydrogen production (green vs. grey) on its isotopic ratio. This can be a measure for classifying hydrogen without knowing the exact source.

Rossegger, Bernhard, Grabner, Peter, Gschiel, Kevin, Vareka, Martin

The Effect on Soot Handling and Friction of Selected Dispersant Additives for Next Generation Transportation Sector Oils

2024-01-4301

11/5/2024

Next generation lubricating oils for transportation sector require higher durability in operation, compatibility with new engine technologies and aftertreatment devices as well as high fuel economy (FE), thus contributing to the reduction of CO2 emissions, both in passenger cars and heavy-duty vehicles. The current paper aims to highlight the impact of dispersant main properties in preventing sludge and deposits formation on engine surfaces. The effect on frictional properties of lubricating oils through a multi-step activity was evaluated. Oil contamination by soot is a big concern not only for diesel but also for new generation of direct injection gasoline (GDI) engines. The presence of soot leads to oil thickening that heavily impacts on friction coefficient thus enhancing the role of dispersant in controlling soot and related viscosity increase and, indirectly, fuel consumption for long running periods. After an introduction on dispersant technologies, the focus of the paper moves on an innovative lab-scale methodology based on optical microscopy for the direct assessment of the dispersing capacity of oil. This methodology was firstly applied to SAE Grade 15W-40 heavy duty (HD) oils contaminated with surrogate soot, where different dispersant systems were evaluated. In parallel, in order to simulate the soot effect on GDI oils, the aforementioned methodology was also applied on 0W-12 oils. Finally, the different dispersants were evaluated on the standard Mack T8E engine test for a duration of 300 hours, providing a ranking in terms of soot handling properties. The second part of the paper deals with the investigation of the frictional properties of dispersants, both in GDI and HD engines. After a brief introduction on lubrication and tribology fundamentals, the authors considered an experimental activity based on a tribological test by using the Mini Traction Machine (MTM). For GDI engines, 0W-12 oils were tested at three different temperatures in order to evaluate the friction coefficient (COF) profile of oils as fresh. Afterwards, the authors considered the effect of the oil aging on friction losses, mainly consisting in soot loading and oxidation, through a two-step evaluation process: firstly, testing by MTM, the drained oil that achieved the low performance in soot handling at the Mack T8E. Secondly, from this oil, different candidates samples containing increasing amount of soot were derived and tested by MTM as fresh and after a laboratory ageing procedure: a performance comparison between aged oil vs fresh oils with and without soot was done in order to assess the effect of both soot content and ageing on frictional properties of lubricating oil. The described experimental steps demonstrated that dispersant characteristics of engine oil play an important role not only in maintaining engine cleanliness but also in controlling the increase in friction during operation that influences fuel economy of finished product.

Lattuada, Marco, Manni, Massimo, Notari, Marcello, Ferraro, Giovanni, Fratini, Emiliano

Lubricating Oil, Aircraft Piston Engine (Ashless Dispersant)

J1899_202410 (Current)

10/28/2024

This SAE Standard establishes the requirements for lubricating oils containing ashless dispersant additives to be used in four-stroke cycle, reciprocating piston aircraft engines. This document covers the same lubricating oil requirements as the former military specification MIL-L-22851. Users should consult their airframe or engine manufacturer’s manuals for the latest listing of acceptable lubricants. Compliance with this specification must be accomplished in accordance with the Performance Review Institute (PRI) product qualification process as described in the documents referenced in 2.1.3. Requests for submittal information may be made to the PRI at the address shown in 2.1.3, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by the PRI. Approval and/or certification for use of a specific piston engine oil in aero applications is the responsibility of the individual equipment builders and/or governmental authorities and may be accomplished by compliance with or qualification to this specification.

E-38 Aviation Piston Engine Fuels and Lubricants

Influence of Lube Oil and Fuel Additives on the Particulate Raw Emission Behavior of Gasoline Engines

04-18-01-0004

10/3/2024

The aim of this work was to investigate the influence of different combinations of engine oil and oil additive as well as additivated and unadditivated fuel on particulate emissions in gasoline engines. To accomplish this, load, speed, and type of oil injection were varied on a single-cylinder engine, and the influence on particle number concentration and size distribution were evaluated. The tests were supplemented by an optical investigation of their in-cylinder soot formation. The investigation of fuel additives showed no significant differences compared to the reference fuel without additives. However, in the case of oil additives, detergents led to a significant increase in the number of particles in the <20 nm range. This effect occurred when used as both a single additive and a component in the standard engine oil. While viscosity improvers also lead to a measurable, but less pronounced, increase in the particle number concentration, no significant influence can be determined for any other oil additives. The influence of the additive is independent of the type of oil introduction by injection into the intake manifold or direct injection of a premixed oil/fuel mixture.

Böhmeke, Christian, Heinz, Lukas, Wagner, Uwe, Koch, Thomas

Influences of Lubricant Viscosity and Metallic Content on Diesel Soot Oxidation Reactivity

2024-01-5084

8/23/2024

This study examined the effects of lubricant viscosity and metallic content on the oxidation reactivity of diesel particles. In the first part, the factors affecting thermogravimetric analysis (TGA) experiments was discussed and confirmed. The influences of initial soot mass, heating rate, and airflow rate on soot oxidation rate and experimental reproducibility were investigated to develop an optimized TGA method. On the basis of these experiments, an initial soot mass of 2.0 mg, airflow rate of 4.8 L/h, and heating rate of 2.5°C/h were used for all subsequent TGA tests. It could be found that the TGA experiments had high repeatability, and the differences were less than 0.1%. In the second part, a four-cylinder diesel engine was lubricated with seven kinds of lubricant with different viscosity and metallic content by the use of viscosity index improver (VII), antioxidant and corrosion inhibitor (ACI), and ashless dispersant (AD). Particle samples were subjected to TGA to test their particulate composition and oxidation reactivity, such as oxidation rate, characteristic temperatures, and Arrhenius kinetic parameters. It was found that the soot oxidation rate increased significantly with the increase of metallic content in lubricant, but had little to do with lubricant viscosity. When using lubricating oils with different properties and compositions, the activation energy of carbon smoke oxidation ranges from 143 to 187 kJ/mol. This tendency was more remarked as the lubricant additives’ dosage ratio increased. Soot oxidation rate trends were explained by particle properties, including morphology and nanostructure. A smaller size and less ordered nanostructure were associated with a lower activation energy.

Meng, Hao, Yang, He, Zhang, Weili, Xing, Jianqiang, Xu, Yan, Wang, Yajun

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