Browse Topic: Coolants

Items (1,374)
Compared to traditional reactors, lead-bismuth eutectic reactors (LBE) have higher neutron economy and stability. As a device for driving the coolant, the electromagnetic pump features non-contact operation, simplifying the sealing apparatus and achieving complete sealing inside the pump. It meets the requirements of miniaturization and modularity, while offering excellent flow regulation performance. Its input parameters determine the output performance in both performance analysis and structural design of lead-bismuth electromagnetic pumps . This article focuses on a small-scale annular linear induction electromagnetic pump (ALIP) as the simulation object and establishes an electromagnetic pump model. Based on Maxwell’s equations and N-S equations, and with the background of three-dimensional multiphysics coupling of electromagnetic field, flow field and heat transfer field, the coupling mechanism between the flow velocity of LBE and the Lorentz force was studied in detail. From the perspective of electromagnetic-flow coupling, the influence of different coil turns, input currents, and excitation frequencies on the Magnetic flux density and pressure of electromagnetic pumps was analyzed. Finally, a comprehensive analysis of the output characteristics of ALIP under various input parameters is performed, and the research results provide a theoretical reference for the design and optimization of lead-bismuth ALIP.
Peng, ChunyuXiao, Changzhi
With the goal of enhancing diesel engine adaptability to low-temperature environments and exploring cold-start potential at - 50 °C, this paper develops a one-dimensional simulation model for the cold-start system. The model is based on a method that utilizes a diesel heater to warm the coolant, which in turn heats the engine block and oil. The heating condition of coolant and oil of a 10-cylinder V-type engine within a specified time under a -50 °C environment is studied through simulation. We further optimized the cold-start process by enhancing the coolant flow distribution within each circulation circuit to improve overall thermal management and start-up efficiency. The results show that: at an ambient temperature of -50 °C, with a heating power of 80 kW, a total flow rate of 110 L/min, and an engine block flow rate of not less than 54 L/min, the diesel engine can raise the coolant temperature at the engine outlet to 40 °C and the oil temperature to -35 °C within 20 minutes. Through flow optimization, by maximizing the flow rate of the engine block heating circuit and reducing the flow diversion of the intercooler, the coolant temperature at the engine outlet can reach 40 °C in 18.9 minutes, while the oil is heated to -34.9 °C, and the final heating coolant temperature reaches 44.4 °C at 20 minutes. Compared to the situation without flow optimization, the time for the engine outlet coolant temperature to reach 40 °C was shortened by 0.55 minutes, and the final heating coolant temperature increased by 2.2 °C. Based on relevant experiments and the dynamic viscosity curve of 5 W engine oil, this paper holds that the starting conditions of a diesel engine can be met when the engine outlet coolant temperature reaches 40 °C, and the engine oil temperature reaches -35 °C.
Wang, JingfeiXie, PengWang, ZhuoXia, YingqiuZhang, XiaodongChen, KeWang, Guodong
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, ShengchenZhao, Zhenfeng
In permanent magnet synchronous machines (PMSMs) ohmic losses occur in the stator windings. Reducing these losses contributes to a higher efficiency and increases the vehicles range. An effective approach to reduce frequency-dependent AC conduction loss is the use of litz wires. In addition, direct cooling helps to reduce DC conduction loss and winding temperatures. Therefore, this work presents a multiphysical modeling approach of a direct-cooled litz wire winding in a PMSM. It combines loss modeling of the winding with novel thermal and hydraulic calculation methods. AC conduction loss due to skin and proximity effect and DC conduction loss are modeled temperature dependent. Scaled-down conjugate heat transfer simulations are used to determine the heat transfer coefficient (HTC) between wires and coolant. Additionally, the pressure drop is derived and converted into parameters for use in a porous media model. The derived parameters are used to generate surrogate models to enable computationally efficient predictions. Using the developed methods a case study is carried out. The influence of the number of turns per slot, litz wire diameter and number of parallel litz wires is investigated. In order to isolate the influence of the winding configuration, the geometry of the PMSM and the coolant volume flow remain constant. Performance indicators are energy consumption during a duty cycle, winding mass and pressure drop. Based on this study it is shown that the stator winding design is a multiphysical compromise. The method enables a targeted design of the winding configuration with respect to various objectives and facilitates the assessment of their influencing factors on the overall machine characteristics under conflicting performance requirements.
Blaschke, Wolfgang MaximilianMengoni, LeonardList, AdrianKulzer, André Casal
With the continued expansion of electric mobility, liquid-cooled thermal management systems have become indispensable for ensuring the performance, durability, and safety of automotive battery packs. This work presents a novel cooling-plate design that integrates offset strip-fin turbulators to enhance convective heat transfer between lithium-ion cells and the circulating coolant. A comprehensive multi-region CFD model of the full battery pack is developed, incorporating an implicit lumped-parameter representation of cell heat generation. The numerical predictions are validated against dedicated experimental measurements available in the literature. Subsequently, a parametric study is conducted in which the number of hydraulic sub-modules and the inlet/outlet configurations are systematically varied to generate all feasible design permutations. The resulting configurations are compared to assess thermal performance and to quantify the benefits—as well as the potential penalties—introduced by the turbulators relative to the experimentally validated baseline.
Montenegro, GianlucaOnorati, AngeloDella Torre, AugustoTariq, Muhammad HasnainBonetti, Elisa
Abstract: This research paper investigates the performance of FKM (Fluorocarbon) seal material when exposed to a 50:50 ethylene glycol-water mixture. The study aims to determine the volume change percentage and Hardness change of FKM elastomers under standardized testing conditions. The experimental approach follows ASTM D471 and ASTM 2240 guidelines, focusing on weight and hardness measurements of the test samples to establish a success criterion. The results provide critical insights into the chemical compatibility and durability of FKM elastomers in Aerospace and industrial applications where ethylene glycol-water mixtures are commonly used. The findings contribute to enhanced material selection and design considerations for sealing applications subjected to glycol-based fluids. Samples of FKM material were immersed in the fluid at controlled temperatures and durations, simulating real-world operational conditions. The primary metric of interest, volume change percentage and Hardness change, were assessed through precision measurement techniques. Weight changes before and after immersion were also recorded to correlate material absorption characteristics with the success criteria. Success thresholds were established based on industry requirements for seal integrity and operational reliability. Preliminary results indicate that FKM exhibits minimal volume expansion and hardness change under specified conditions, aligning with the acceptance criteria. These findings support the suitability of FKM seals for long-term use in coolant systems, with implications for material selection and design in demanding applications. This research contributes to the development of durable sealing solutions, ensuring reliability and safety in systems utilizing ethylene glycol-based coolants. Keywords: FKM, Volume Expansion, ASTM D471
Yarolkar, MakrandPatil, SandipSingh, Tanul
A full lithium-ion battery (LIB) pack has hundreds to thousands of cells, coolant flow lines and channels, and channel bends to control cell temperature within its operating window and minimize cell internal resistance, aging, and fire risk. A 75 kWh LIB pack has four modules, and each has 23–25 bricks. Two challenges in battery state predictions for hot and subzero temperatures are battery temperature (Tbatt ) and coolant flow within the whole pack. In this work, a 1D 75 kWh full-pack model with its thermal management system is developed using a holistic reverse-engineering method, which can predict Tbatt at any bricks/modules and inlet/outlet coolant flow characteristics. A Tesla Model Y equipped with dual e-motors is tested on an in-house state-of-the-art chassis dynamometer. The test data at V = 60–80 km/h, 100–150 A constant discharge, and Tbatt = −10°C to 40°C are used to develop the model. The 75 kWh pack model features 4000+ cylindrical cells (96S46P, Panasonic 21700-format), 20+ coolant lines (or plates, tubes), and 700+ flow channels. The model considers heat exchange from cells to the ambient air via coolant (water-glycol), coolant channel walls, adhesive bonding, trays, and cases. Four forced convective heat transfer coefficient correlations (α) from the coolant to the walls are used to predict coolant outlet temperature (T cool, out ) and Tbatt at different bricks. Three coolant flow losses correlations (K) due to pipe friction, and pipe bends are used to predict the coolant pressure drop ∆Pcool across the pack. Optimal α and K correlations are identified using the fully validated pack model, and the transient temperatures at any cell in bricks and the inlet/outlet coolant flow characteristics are well predicted with over 90% accuracy. This work provides guidelines for selecting optimal α and K correlations to develop any 1D fully liquid-based battery pack models for all-weather driving.
Sok, RatnakKusaka, Jin
This paper presents transient, complex, multi-species, multiphase, 3D CFD transient simulation of engine coolant pump weep chamber for predicting coolant evaporation. The engine coolant pump contains a rotating mechanical face seal to prevent liquid coolant leakage at the rotating interface. During normal engine operation, a small amount of coolant vapor is expressed by this rotating seal; this vapor can condense on solid surfaces within the weep chamber. The coolant collected in weep chamber evaporates from the chamber and exits out of the weep chamber in vapor form. Evaporation rate of the coolant is a primary factor deciding weep chamber size. Evaporation rate of coolant depends on several factors – ambient humidity, ambient temperature, flow of air in and out of the weep chamber, pump temperature, and pump rotational speed. Weep chamber is small in dimensions (~ 100 cm^3) and dependence of coolant evaporation on several factors results in necessity of an accurate and predictive simulation methodology while designing a coolant pump. The simulation of evaporation is challenging due to need of modeling multiple species, multiple phases, and transient physics. In current work, an innovative 3D CFD simulation approach for predicting coolant evaporation in weep chamber is developed. The simulation approach can account for variation of ambient conditions, pump speed, coolant quantity, and coolant temperature. Evaporation rate prediction from the simulation is compared with a coolant pump evaporation rig test data and the results are found to be correlating within engineering accuracy. The simulation approach will be helpful in coolant pump design development work for determining design features of a weep chamber.
Tawar, Ranjit RamchandraDrechsel, JamesBedekar, SanjeevNallamothu, Sravan
The performance of a full battery pack with its effective thermal management system (BTMS) depends on coolant flow and heat transfer characteristics inside the pack. To develop a full BTMS using model-based design (MBD), the model must capture the coolant pressure drop ∆?? and heat-exchange performance from the cell to ambient air via the coolant, cooling flow channels, air gaps, and pack cases. Predicting battery pack responses (i.e., voltage, SOC, temperature) under all weather conditions is a challenge, as a complete pack contains several hundred to thousands of cells, coolant lines, coolant line bends, and coolant channels. This work presents a detailed approach to identifying heat transfer and ∆P correlations that can capture the real-time thermal-electrical performance of a mass-produced LIB pack under constant speed (in winter) and transient driving (in summer). A vehicle test is conducted using a Tesla Model Y, 2-motor model equipped with a 75-kWh LIB pack. The LIB pack's thermal and electrical performance is recorded at 60 km/h under cold conditions and during transient driving in summer. The pack is based on the 2RC equivalent circuit model, reduced from the P2D-based NCA/Gr-SiOx Li-ion cell, to accelerate simulation times at the pack and vehicle levels. The approach to identifying ∆P and heat transfer correlations are discussed, with pack model validations under coolant temperatures ranging from 0 to 40 °C and coolant flow rates of 4 to 14 L/min. The thermal and electrical performances (voltage, SOC, ∆P, and temperatures of the coolant, bricks, and modules) of the high-fidelity battery pack model are validated against vehicle test data at 60 km/h driving (ambient temperature Ta = -10 °C) and repeated FTP+HWFET cycle (Ta = 30°C). The whole pack model achieves an average accuracy of 90%, and this work can serve as a guideline for designing battery packs with their BTMS using MBD.
Sok, RatnakKusaka, Jin
Linear time-invariant (LTI) reduced-order models (ROMs) have been widely used in battery thermal management simulations due to their low hardware requirements, high computational efficiency, and good accuracy. However, the inherent assumption of LTI behavior limits their applicability in scenarios with varying coolant flow rates, where this assumption is no longer valid. To address this limitation, a novel ROM is developed by decomposing the entire battery thermal system into two subsystems. All solid components are modeled as a traditional LTI ROM, while the coolant channel is represented using Newton’s cooling law. The two subsystems are then coupled through the exchange of heat transfer rate and temperature at the fluid–solid interface between the coolant and the cold plate. Model fidelity is further enhanced by introducing a spatially distributed heat flux during the generation of the LTI ROM for solid components. Validation is performed against CFD simulations at both module and pack levels, under constant and varying flow rates. The results demonstrate that the proposed ROM achieves high accuracy while requiring several orders of magnitude less computational time than the corresponding CFD models.
Guo, JiaChen, GuijieMa, ShihuHu, XiaoLi, JingSong, ShujunHuang, Long
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, ChangjooLee, KyuminKim, SeonyeongNam, ChoonhoYoo, Jihun
Renewable gasoline offers significant benefits in reducing greenhouse gas (GHG) emissions. In this study, five gasolines with different renewable hydrocarbon classes and varying distillation curves were taken to investigate their effect on particle number (PN) emissions in a spark-ignition GDI engine at 10 bar indicated mean effective pressure (IMEP) and 2000 rpm. The engine coolant temperature was varied from 90°C to 35°C to investigate the effect of fuel evaporation on soot formation. Injectors with various spray plume targets and start of injection (SOI) timing (300° and 260° bTDC) were used to assess how different gasolines affect engine performance and to determine engine calibration requirements. A simplified transient cycle examines how engine motoring influences PN emissions for test gasolines. A high-speed camera and endoscope were used to identify the sources of soot during fuel combustion. Simulations were done to assess the quality of fuel-air mixing in support of the experimental data. The results revealed that the type of hydrocarbons in gasoline was crucially affecting PN emissions. Particles with >10 nm increased with increasing fuel’s aromatics. Paraffin-rich gasoline showed 71% and 98% lower PN than aromatics-rich gasoline under hot and cold engine conditions. Paraffin-rich gasoline showed lower PN in cold tests than in hot tests with retarded SOI. Replacing ~10% paraffins with olefins and naphthene reduced >10 nm PN by 15-77%. However, replacing 19% of paraffins with olefins and naphthene increases PN emissions. Optimal SOI timing reduces PN by 80% for aromatics-rich gasoline. Fuel consumption and hydrocarbon (HC) emissions increased with increasing aromatics and paraffins in gasoline under cold conditions. Yellow flames on the piston top and near the injector tip were the primary sources of soot. Simulation results showed that the liquid fuel mass increased by 14% when the coolant temperature was reduced by 55 K.
Muniappan, KrishnamoorthiDahlander, PetterHelmantel, AyoltAlemahdi, NikaLehto, Kalle
The performance and longevity of lithium-ion (Li-ion) batteries in electric vehicles (EVs) are critically dependent on effective thermal management. As internal heat generation during charge and discharge cycles can lead to uneven temperature distribution, exceeding optimal operating limits (25 - 40°C) can significantly degrade battery performance and lifespan. This study presents a performance evaluation of a novel liquid-based Battery Thermal Management System (BTMS) featuring a dual-directional coolant channel configuration designed to enhance thermal uniformity and heat dissipation. The proposed configuration combines horizontal and vertical coolant passages in an indirect cooling layout to address the limitations of conventional serpentine-type channels. A comprehensive thermal analysis was carried out under realistic loading conditions using three coolant types: water, ethylene glycol- based G48, and graphene-enhanced water nanofluids. These were evaluated for thermal conductivity, heat transfer efficiency, and effectiveness in minimizing temperature gradients. Graphene nanofluids exhibited superior performance due to their high thermal conductivity and enhanced convective heat transfer capabilities. Additionally, the effect of varying coolant flow rates was analyzed to simulate different operating scenarios. While increasing flow rates improved cooling effectiveness, the study also identified a threshold beyond which performance gains diminished. The novel dual-channel design demonstrated significant improvements over traditional serpentine configurations, including a notable reduction in maximum cell temperatures and enhanced temperature uniformity across the battery pack. This improvement is critical in reducing hotspots and extending battery health. The dual- directional flow facilitates more efficient convective heat transfer, offering a promising advancement in BTMS design. The integration of advanced nanofluid coolants with an innovative channel configuration pave the way for the development of more efficient, reliable, and thermally stable battery systems in next-generation electric mobility.
Selvan, Arul MozhiPeriyasamy, MuthukumarR, ThiruppathiPrasad S, HariRaghav, RBoddu, Sriram Pydi Aditya
The performance and longevity of Li-ion batteries in electric vehicles are significantly influenced by the cell temperature. Hence, efficient thermal management techniques are essential for battery packs. Simulation based optimization approaches improves the efficiency of the battery pack thermal management during the early stage of product development. In this paper, a simulation-based methodology has been introduced to increase the heat transfer from/to coolant via cooling plate as well as to reduce the heat transfer from/to the external environment. The heat transfer coefficient between cooling plate and coolant needs to be enhanced to achieve efficient heat transfer through cooling plate, without exceeding the coolant pressure drop the target limit. A one-dimensional simulation methodology described in this work analyzed numerous design of experiments for coolant layout without performing CAD iteration loops and optimized the cooling channel width, height and number of channels to maximize the heat transfer coefficients within the pressure drop target. A reduction of 30% in pressure drop and 36% energy saving in coolant pump along with 10% enhancement in heat transfer effectiveness has been achieved with this method. This study also evaluated the sensitivity of each housing surface in heat transfer to external ambient. Simulation results provided recommendations for thermal insulation at minimum number of surfaces with thermal conductivity and thickness guidelines which gives maximum effectiveness at minimum material addition and cost. In the final part of this work, both the solutions have been integrated into the battery pack and compared with the baseline for energy consumption. A standstill parking condition at different low ambient conditions for different durations has been considered and energy consumption for pre-heater circuits has been evaluated. Results show that the energy consumption for pre-heater circuits was reduced by at least 31% to a maximum of 84% for the parking duration of 48 hours and 8 hours cases respectively. Thus, the simulation based integrated approach of two solutions helps to design energy efficient battery thermal systems during the design stage for Electric vehicles.
U, ReghunathP S, Shebin
This paper presents Nexifi11D, a simulation-driven, real-time Digital Twin framework that models and demonstrates eleven critical dimensions of a futuristic manufacturing ecosystem. Developed using Unity for 3D simulation, Python for orchestration and AI inference, Prometheus for real-time metric capture, and Grafana for dynamic visualization, the system functions both as a live testbed and a scalable industrial prototype. To handle the complexity of real-world manufacturing data, the current model uses simulation to emulate dynamic shopfloor scenarios; however, it is architected for direct integration with physical assets via industry-standard edge protocols such as MQTT, OPC UA, and RESTful APIs. This enables seamless bi-directional data flow between the factory floor and the digital environment. Nexifi11D implements 3D spatial modeling of multi-type motor flow across machines and conveyors; 4D machine state transitions (idle, processing, waiting, downtime); 5D operational cost breakdowns covering electricity, tooling, labour, coolant, and depreciation; 6D AI/ML-based failure prediction using temperature and pressure inputs; 7D predictive downtime triggers based on learned thresholds; 8D sustainability analytics measuring CO₂ emissions per motor; 9D workforce optimization via virtual shift scheduling and fatigue simulation; 10D supply chain resilience through simulated part delays and buffer modeling; and 11D risk and quality management using defect simulation and risk scoring. All data are generated live and visualized through Grafana dashboards, enabling real-time monitoring of OEE, energy use, defects, and AI-based alerts. Nexifi11D establishes a unified, cyber-physical platform for intelligent, sustainable, and predictive manufacturing, making multidimensional factory optimization practically demonstrable within one connected environment.
Kumar, RahulSingh, Randhir
The inclusion of the cabin in HVAC simulations gained more importance with the introduction of BEV’s. Thermal management and efficiency being in the forefront, exploration for the possible opportunities to reduce the energy consumption for meeting the comfort of passengers gained importance. The energy consumed by the Electric coolant or air heaters for heating the cabin at extreme cold ambient temperatures to deliver similar comfort to that of an ICE version is 2 to 3 times that of the energy required for cooling the cabin in a high ambient condition. Even during the sizing of HVAC system, if traditional method of ambient or fresh air conditions is considered for calculating the requirements, the result is we would require a product which will have unrealistic performance demand. Hence to explore different possibilities for studying the system, usage of recirculation air was considered as one of the options. This paper talks about the approach followed in creating the cabin model in 1D simulation using AMESIM and using it effectively for studying the impact in the performance of the system at various recirculation conditions. The cabin model is discretized into various rows, and the floor part of the model is considered as a separate volume. The model is optimized for both the recirculation air temperature and the cabin air temperature. The recirculation air is then mixed with fresh air according to the required percentage using an air mixture before using it as the inlet condition of the heater core. The model performance is also verified with multiple vehicle test data, proving the robustness in the modelling approach and accuracy in prediction.
Veerla, EswarSubramanian, Karthik
With the increasing tonnage of electric heavy commercial vehicles, there is a growing demand for higher power and torque-rated traction motors. As motor ratings increase, efficient cooling of the EV powertrain system becomes critical to maintaining optimal performance. Higher heat loads from traction motors and inverters pose significant challenges, necessitating an innovative cooling strategy to enhance system efficiency, sustainability, and reliability. Battery-electric heavy commercial vehicles face substantial cooling challenges due to the high-pressure drop characteristics of conventional traction system cooling architectures. These limitations restrict coolant flow through key powertrain components and the radiator, reducing heat dissipation efficiency and constraining the operating ambient temperature range. Inefficient cooling also leads to increased energy consumption, impacting the overall sustainability of electric mobility solutions. This paper presents a novel approach of optimizing coolant flow by reconfiguring the traction system layout and redesigning the coolant flow paths. These enhancements increase coolant flow by 100–200% compared to conventional systems, allowing the coolant pump to operate within its peak efficiency range. As a result, pumping power consumption is reduced by at least 33%, minimizing parasitic losses, improving vehicle range, and supporting green mobility initiatives by reducing energy waste. The increased coolant flow through the radiator enhances the tube-side heat transfer coefficient, significantly improving radiator heat dissipation and allowing for higher ambient temperature operation. Additionally, the optimized cooling system enables lower fan speeds, reducing both power consumption and cooling fan noise. This verified thermal management strategy, successfully implemented in production-ready heavy-duty electric vehicles, has effectively prevented traction propulsion motor power de-rating, leading to improved vehicle performance, energy efficiency, and long-term sustainability. Furthermore, a unique control strategy has been developed to dynamically regulate coolant pump and radiator fan operation by continues monitoring of each aggregate device temperatures. This optimized thermal management system ensures robust and efficient cooling.
Dixit, SameerPatil, BhushanGhosh, Sandeep
In current scenario, demand for alternate energy is increasing due to depletion of fossil fuels and countries working to achieve carbon neutrality by 2050. Hydrogen being a cleaner fuel, many OEMs across the world started to work on various strategies like hydrogen combustion engine and fuel cell. Passenger vehicles like buses are at the lookout for fuel cell technology at faster rate than other commercial vehicles. In fuel cell vehicles, cooling system design is critical & complex since it includes fuel cell cooling, Power electronics cooling & battery cooling. In this paper, cooling system design of a Fuel cell electric bus for inter-city application is demonstrated. Radiators and Fans are designed considering overall heat rejection and Coolant inlet temperature requirements of components. Cooling system circuit and pump is decided to meet the coolant flow rate targets. Flow simulation and thermal simulation done with the help of simulation models built using software KULI to predict coolant flow rate and temperature across each component. Fuel cell circuits, Power electronic circuits, Battery circuits modelled in KULI with all components in the circuit. KULI predicted results signifies good co-relation with actual results.
M S, VigneshKiran, Nalavadath
This paper presents an innovative in-lab accelerated testing approach for chassis-mounted components, with a particular focus on the cooling module of commercial vehicles. The proposed method simulates real-time data acquired from field operations and replicates all critical chassis modes, including torsion. Additionally, real-time coolant circulation at specified pressure and temperature maintenance are feasible during durability testing, enhancing the realism of the test environment. The cooling modules, comprising the radiator, intercooler, and charge air cooler (CAC), often experience failures due to various multi-axial inputs and chassis modes. This paper introduces an innovative methodology for replicating field conditions in the lab, utilizing seven servo-hydraulic actuators to simulate multi-axial inputs. The accuracy of in-lab simulation for the acceleration levels at input and response locations of the cooling module exceeds 90%. This makes it a preferred choice for test engineers to simulate field failures or validate designs well in advance of final production, thereby avoiding issues at later stages of vehicle launch. This innovative approach offers flexibility to accelerate the test duration while ensuring the retention of over 90% of the damage observed in real-world conditions. By utilizing the same chassis frame and mounting locations, the test maintains consistent boundary conditions, providing reliable and accurate results. This method significantly enhances the efficiency and effectiveness of testing processes for commercial vehicle components, ensuring robust and reliable performance. [4]
V Dhage, YogeshSatale, Sunil
Maximizing vehicle uptime and reducing maintenance costs are critical objectives in modern automotive systems, making efficient resource utilization a top priority. One of the key factors is engine oil life or degradation, which directly affects the engine performance, longevity, and overall vehicle efficiency/fuel economy. Most vehicles tracks engine oil life solely on a fixed mileage interval while few uses dedicated sensor, which is costly and requires service and maintenance. As the engine oil degrades, it reduces Oil Total Acid Number (TAN) increases while Oil Total Base Number (TBN) decreases. It is recommended that maximum usable life of the engine oil is up to the crossover point between oil TAN and TBN (as the engine oil degrades). Vehicle driving pattern governs the occurrence of crossover points with respect to vehicle mileage. Based on this fundamental concept, an XG-Boost machine-learning algorithm is trained using vehicle Controller Area Network (CAN) channels and varying oil TAN and TBN parameters, derived from the vehicle-level measurement data available for the entire life cycle of engine oil in operating condition. The developed model based on CAN channels like engine rpm, engine torque, gear position, engine power, coolant temperature and odometer readings accurately predicts engine oil TAN and TBN parameter. The cross over point of TAN & TBN is accurately forecasted as seen in correlation results. An interactive user interface is designed and developed to display the deterioration in terms of remaining useful life of the oil to customers in vehicle driving condition.
Dusane, MangeshTade, VilasIqbal, Shoaib
One of the most important components of an electric vehicle is the drive motor. Induction motors are often used for this purpose. During operation of these motors, power loss occurs, especially at high speeds. This power loss corresponds, among other things, to the sum of winding losses, iron core losses and mechanical losses. The power losses generate heat, which causes the temperature in the rotor and stator to rise. The increase in temperature of the components inside the motor can lead to premature wear and fatigue failure. To prevent overheating, the motors are air- or water-cooled. Water cooling can be achieved, for example, by means of jacket cooling. Here, the heat generated is dissipated directly by forced convection. However, the cooling jacket makes it difficult to determine the temperature inside the motor. Determining these temperatures is necessary to protect the motor from premature fatigue. The temperatures inside the motor during operation are of particular interest for test bench trials. This article presents a thermal transient modelling of a water-cooled electric motor for electric vehicle applications based on test bench experiments. This article presents a thermal transient model of a water-cooled electric motor for electric vehicle applications based on test bench trials. The model provides insights into temperature profiles inside the electric motor, which can be used for testing electric motors on test benches. This allows the effects of changes in test bench parameters to be identified in advance, which is a useful tool for test bench engineers. Using ANSYS Motor CAD software, a simulation is created based on real test bench parameters and a real test program. The electric machine created in the simulation resembles the geometry of the real drive machine on the test bench. The model created is adjusted using the test bench parameters coolant and ambient temperature, speed of the electric machine and surface temperatures. The special feature here is the determination of the surface temperature using thermography. A thermal imaging camera is used to create infrared images of the electric machine during operation, with each pixel corresponding to a temperature measurement point. This allows significantly more temperatures to be recorded than, for example, with thermocouples. The purpose of the work is to use simulation to determine the temperatures inside the machine based on surface temperatures measured using thermography.
Schamberger, StephanieReuss, Hans-Christian
The reliability and durability of vehicles are crucial for the acceptance of new technologies by customers. Realistic test methods are necessary to validate or ensure the lifespan of vehicles and their components, particularly regarding specific conditions such as freeze start. This article provides an overview of the current state of research on the effects of freeze starts on the degradation of fuel cells. With this knowledge, relevant operating and boundary conditions for potential damage of the fuel cell are identified (e.g. start temperature, duration in subzero operation, dehydration). The field data from the BMW demonstrator fleet of iX5 Hydrogen Next were analyzed to gain insights into realistic freeze start related stress to the fuel cells. The dynamics of heating rates and the influence of the operating strategy are best represented on a Fuel Cell System (FCS). An experimental setup for a stack centered test on a FCS was developed including a climatic chamber and a subzero coolant supply in this study. The identified automotive conditions could be implemented similarly and reproducibly for the stack. In total of 140 freeze starts with the start stack temperatures between - 7 °C and - 18 °C were performed. These test results and the vehicle data were compared, and the limitations of this accelerated stress test are stated. The advantage of this method is the feasibility to validate the lifetime regarding freeze starts within a period of 1-2 month in 24/7 operation. The occurred problems during test development and their solutions are also described, and suggestions for improvement for less damaging freeze starts process are given.
Schwarz, MarkusAlbert, AlbertEichel, Rüdiger-A.
In automotive applications a power electronic converter is used for energy conversion between battery and electrical machine. For high performance drives a lightweight design is demanded. Additionally, a higher efficiency of the inverter results in lower cooling requirements but is often achieved by increasing component weight. Hence, thermal modeling of the components and their interactions is essential to determine the best compromise between weight, efficiency and cooling requirements. In traction inverters the DC-link capacitors, power modules, high voltage electrical connections and low voltage devices dissipate power. In this paper the focus is on the thermal modeling of the DC-link capacitor, power modules and high voltage electrical connections and their system, as the performance of the inverter is defined by these components. The thermal models are derived based on physical properties and geometries. First, the DC-link capacitor thermal model is presented and considers the anisotropic heat conductivity of the capacitor coil and the inhomogeneous loss feeding in the busbars. Next, the thermal model of a power module and heatsink is explained taking temperature dependent material properties into account. Based on the input temperature of the coolant and heat dissipation of the power modules the temperature rise of the fluid is calculated. Furthermore, the electrical connections, consisting of a combination of cables, busbars and shunts are thermally modeled. With the individual component models combined an overall inverter thermal model is developed. A comparison between the thermal system model and measurements is carried out finally. For this several temperature sensors were integrated into an inverter. By taking the measured temperatures into account, the thermal system model is validated for stationary and dynamic load points. As all models are based on geometric and material properties it is possible to observe the impact of sizing in the future.
Blaschke, Wolfgang MaximilianMengoni, LeonardPflüger, RobinKulzer, André Casal
This study presents a methodology to develop a new 25kWh battery pack for off-highway application. Initially an enclosure space is extracted from tractor model maintaining minimum space with adjacent components. Based on available space, various combination of cell form factors and different cell chemistries are evaluated considering operating ambient temperature range (-20 to 45 deg C) and charge/discharge rate 1C. Cylindrical NMC type cell with indirect cooling system fulfils all our technical requirements. However, complete battery pack thermal simulation is carried out for ensuring battery pack safety and limited deterioration with different discharge rate and wider temperature range. The battery pack model contains multiple cells, bricks, and modules with numerous coolant pipes and flow channels. Cell characterization experimental data is used for estimating cell thermal capacity and IR behavior. Battery pack model is tested with different Charge/discharge rates. Five thermocouples, pressure, and coolant flow sensors are installed on the different battery cells, bricks, and modules to capture the time-series thermal and electrical performance changes. These data are used to validate the integrated battery pack and its TMS cooling circuit. It is observed correlation above 90% for temperature, pressure and velocity between simulated and experimental values.
Nain, AjayLamba, Shamsherjayagopal, Sdhir, Anish
In the evolving landscape of energy efficiency and sustainability, understanding machine behavior in real-world operating conditions is essential. This solution introduces a data-driven Energy Management Dashboard designed to analyze and report critical machine parameters by leveraging LFI (Leverage Fleet Intelligence) and LFI Data (Local Field Intelligence Data). The tool serves as a robust solution for engineering and operations teams to gain actionable insights into machine performance and exposure. By tracking key parameters—such as engine fan speed, coolant temperature, and machine speed—across a fleet of machines (with support for over 1100 unique signals), the solution enables real-time monitoring and historical analysis. It helps identify when parameters go outside their specified limits and assesses the resulting impact on overall machine performance. The core functionality includes: Monitoring machine operating conditions under real field environments. Correlating parameter anomalies with performance degradation. Identifying exposure and usage trends based on location and operating conditions. Recommendations on potential impact of parameter value variations on the Engine Torque, malfunction in specific features of the tractor (machine). This solution architecture integrates seamlessly with existing data pipelines and leverages LFI data for contextual insights. The development process involved collaboration with the Ruse squad to ensure relevance to on-field challenges. The expected outcomes include improved visibility into machine usage, early detection of potential issues, and enhanced data-driven decision-making for field operations and energy management. By transforming raw machine data into clear visual insights, this solution empowers teams to take proactive measures in improving efficiency and reliability.
Nandre, RatnapratikJoshi, Aaditya
Single-zone cabin climate control systems have been standard for decades in passenger cars. Looking at the technology trend, which is transitioning from single-zone to multi-zone automatic control systems, it is now possible to provide zonal comfort tailored to the individual requirements of each passenger. In current single-zone climate control systems, maintaining the cabin temperature as stated by the passenger has been straightforward and can be achieved with slight calibration efforts using the present set of parameters and sensors until now. In this work, a multi-zone climate system highlighting the importance of individual calibration parameters in improving cabin comfort when transitioning from a single-zone to a multi-zone climate control system is proposed. As multi-zone climate systems are based on passenger set temperature requests for individual zonal comfort, appropriate controller fine-tuning is challenging when an input is taken from various sensed parameters, including cabin temperature, solar load, ambient temperature, coolant temperature, evaporator outlet temperature, and air quality. It offers valuable insights into the necessary software calibration corrections to ensure optimum zonal comfort for passengers. It is observed that refinement of key parameters enhances passenger comfort and shortens the time required to achieve comfort conditions during the multi-zone calibration process.
Varma, MohitSwarnkar, Sumit KumarBHOSALE, KRISHNAPatil, PrashantSardesai, Suresh
High Performance Resistors (HPR), also known as brake resistors are used in zero emission vehicles (ZEVs) to dissipate excess electrical energy produced during regenerative braking, as heat energy. It is necessary to use a suitable cooling technique to release this heat energy into the atmosphere in a regulated manner. Currently in most of the ZEVs, liquid cooled HPR with its dedicated heat exchanger and other auxiliaries such as pump, surge tank, Coolant and coolant lines, is used which increases the cost, packaging space and assembly time. This paper presents air cooling as a substitute heat-exchanging technique for high-performance resistors which eliminates the need of auxiliaries mentioned above, resulting in space optimization and reduction in assembly time. An air cooled HPR, designed for this study consists of a heat exchanger, which accommodates a resistor wire within its tubes. The design was made to fit commercial vehicle use, specific to trucks, due to packaging constraints in vehicle under hood. 1D simulation model made with MATLAB Simulink was used to analyse this design's heat rejection capabilities. The results conclude that for sufficient air flow rate, air cooled HPR can be used as an alternative in trucks.
Menariya, Pravin GaneshKumar, VishnuArhanth, MahimaUmesha, SathwikJagadish, Harshitha
A cold start occurs when the engine is cranked after being off for a long time, enough for its temperature to drop down to the cold ambient levels. Cold start in an engine is a critical phase as it is characterized by elevated emissions. During a cold start, exhaust components such as catalytic converter do not operate in its optimal temperature zone leading to reduced efficiency in emission control. New regulations for engine emissions are becoming stringent for this condition, hence it is important to accurately determine cold start condition in an engine to optimize the emissions control strategy. Accurate engine off time calculation plays a crucial role in cold start detection, emissions control and On-Board Diagnostics (OBD-II) decision making. This engine off time if greater than 6 hours indicates one of the conditions to confirm a cold start. Other conditions such as Ambient temperature and coolant temperature along with the engine off time confirms a cold start. This paper presents a novel approach to calculate engine off time without any need for supplementary new hardware, leveraging detection of cold start to meet the new requirements for Cold start emission reduction strategy (CSERS) for OBD-II diagnostics. The proposed methodology utilizes Real time clock to estimate the time difference between a successful Engine Cranking and previous engine off to accurately estimate engine off time, enabling precise differentiation between a cold and a warm start.
MUTHA, MAYURESHTalawadekar, PradnyaKale, Upendra
The design of motorcycle engine cooling systems is often hampered by a trade-off between computational efficiency and simulation accuracy, making optimized design iterative and costly. A streamlined, coupled 1D–3D methodology, validated across diverse engine configurations, is needed to address this challenge. This study develops and validates an iterative simulation framework to efficiently optimize cooling systems for various motorcycle engines. The 1D system model defines the performance targets, while 3D CFD analysis enables detailed component optimization (water jackets, radiator airflow); an iterative process ensures the target fulfillment. The 1D–3D coupling analysis methodology is applied to single-, two-, and four-cylinder engines. Results show that the coolant flow velocity within the water jackets are sufficient to ensure effective heat removal of engines and confirms the rational layout design of water jackets. The radiator inlet coolant temperature for the original design of those three engines cooling are 109°C, 107°C, 103°C, respectively. Optimizations (fan shroud redesign, impeller width increase, airflow outlet redesign, air guiding device, radiator shield, wind shielding area reduction, cover removal) are made to increase the radiator airflow velocity by 34.92%, 12%, 7.5%, respectively, and successfully reduces the radiator inlet temperatures below the 100°C target (from 109°C to 99°C, 107°C to 100°C, and 103.8°C to 99.2°C, respectively), with results validated experimentally. The deviation between simulation and experiments is below 7%, confirming the overall reliability and accuracy of the simulation model. The study provides a validated, scalable framework for optimizing motorcycle engine cooling systems, balancing accuracy with efficiency. Its applicability to the cases presented suggests potential for broader use in hybrid and electric powertrain thermal management.
Tan, LibinYuan, Yuejin
Effective thermal management is essential for optimizing the performance and longevity of lithium-ion battery packs, particularly in electric vehicles facing extreme temperature conditions. This study investigates the performance of an indirect liquid cooling system used for pre-cooling stationary electric vehicle battery packs, focusing on scenarios such as vehicle sleep mode in high-temperature conditions. The cooling system, which utilizes a water-glycol mixture flowing at 1.2 L/min, was tested on a battery pack consisting of 36 prismatic battery cells in a thermally isolated chamber, subjected to initial temperatures of 50.0°C, 60.0°C, and 69.5°C. To assess the thermal behavior, 25 thermocouples were strategically positioned on the battery surface, and inlet coolant temperature was monitored via an additional thermocouple. An exponential cooling response was observed across all temperature cases, with maximum temperature difference between the hottest and coldest cells reaching 7.6°C, 10.5°C, and 12.7°C at approximately 15 minutes for initial temperatures of 50.0°C, 60.0°C, and 69.5°C, respectively. While higher initial temperatures led to longer cooling durations (37, 52, and 67 minutes for each case), the final temperature differences converged to similar values, indicating a stable cooling performance across various scenarios. The cooling behavior exhibited consistent thermal patterns, with the temperature differences slightly decreasing toward the end of the tests. Additionally, a resistance-capacitance model was calibrated to predict thermal behavior, achieving a low root mean square error and mean absolute error of 0.4°C and 0.3°C, respectively. These findings offer valuable insights for improving battery thermal management in electric vehicles, particularly during sleep periods, and contribute to the development of energy-efficient and reliable cooling strategies that ensure optimal performance and safety in extreme climates.
Darvish, HosseinCarlucci, Antonio PaoloFicarella, AntonioLaforgia, Domenico
Nowadays, electric vehicles (EVs) are considered one of the most promising solutions for reducing pollutant emissions related to the road transportation sector. Although these vehicles have achieved a high level of reliability, various challenges about Li-ion storage systems and their thermal management systems remain unresolved. This work proposes a numerical and experimental study of a lithium-ion storage cell with a scaled battery thermal management system (BTMS). In particular, a channel plate for liquid cooling is specifically designed and manufactured for the cell under test. The BTMS is based on the development of an indirect liquid cooling system with optimal control of the coolant flow rate to fulfill the thermal requirements of the system. A lumped parameters approach is used to simulate the electro-thermal behavior of the system and to analyze the effects of real-time control strategies on the temperature of the cell under test. An ad-hoc experimental test rig is set up for model and control validation purposes, operating under both steady-state and dynamic conditions in a controlled environment. The temperature management is implemented by using an ARDUINO UNO board, regulating the cooling plate water supply through a variable mass flow rate pump. The overall system model was validated and optimized under various environmental conditions, taking into account the actual on-board behavior of the storage cell under study. Experimental and simulation results demonstrate the effectiveness of the proposed system in maintaining the battery temperature within the optimal range, even under harsh temperature conditions. Although the results are based on a single Li-ion battery cell, they can be suitably extended to a complete vehicle battery pack by considering cell-to-cell thermal and electrical interactions.
Capasso, ClementeCastiglione, TeresaPerrone, DiegoSequino, Luigi
BATSS project objective is to design a safe, effective and sustainable battery pack. To achieve this, the battery system (BS) will be mechanically, electrically and thermally optimized using cutting edge technology. Consequently, the battery system includes innovative 4695 cylindrical cells and advanced thermal management, carried out with the Miba FLEXCOOLER®. This work focuses on the BS thermal optimization using system simulation tools. First a simplified version of the BS is simulated with all physical phenomena involved in thermal behavior to identify first order parameters. It appears that various BS component and heat transfer can be neglected in comparison with the heat transfer due to cooling system. Then the simulation of the full battery system is conducted under nominal condition. Cooling system appears to be performant as it allows a controlled averaged temperature and very low cell-to-cell temperature variability. Finally, impact of both design and operating parameters is evaluated. Simulation shows that the coolant mass flow can be reduced by 70% from its nominal value allowing to maintain good thermal performances while reducing the pressure drop in the cooling system. Impact of the Miba FLEXCOOLER® / cell surface exchange is also investigated. Results demonstrate that increasing exchange surface reduces averaged temperature in the pack but slightly increases cell temperature heterogeneities.
Chevillard, StephanePopp, HartmutGalarza, IgorPetit, Martin
The temperature evolution of lithium-ion cells under operation has a significant impact on their performance, efficiency, and aging. Modeling the thermal status of lithium-ion cells is crucial to predict and prevent undesired working conditions or even failures. In this context, this paper presents a mathematical model to predict the transient temperature distributions of a lithium-ion polymer battery (LiPo) cooled by forced convection via a specially designed channel plate for liquid cooling. For the battery modeling, Newman’s pseudo-2D approach was used to perform a computational fluid dynamics (CFD) analysis. It assumes that the porous electrode is made of equally sized, isotropic, homogeneous spherical particles, which results in smooth, uniform intercalation/de-intercalation of lithium inside the electrode. Also, the channel plate geometry and the cooling liquid fluid-dynamic behavior were simulated with a commercial code based on the finite volume method. The model has been set up and validated through experimental measurements performed on the LiPo and a 3D-printed sample of the cooling plate. Both electrical and thermal parameters of the battery and the refrigerant circuit were collected during the tests at different ambient and charge/discharge conditions. The simulated results were in good agreement with the experimental data. The electro-thermal and fluid-dynamic predictions of the developed model can be used for “test-before-invest” industrial strategies to support the design of battery cooling systems with high performance.
Ferrari, CristianMagri, LucaSequino, Luigi
The primary approach to meet the objectives of the EU Heavy Duty CO2 Regulation involves decarbonizing the road transport sector by battery electric vehicles (BEV) or hydrogen-fueled vehicles. Even though the well-to-wheel efficiency of hydrogen-fueled powertrains like fuel cell electric vehicles (FCEV) and H2-internal combustion engines (H2-ICE) is much lower in comparison to BEV, they are better suited for on-road heavy-duty trucks, long haul transport missions and regions with scarce charging infrastructure. Hence, this paper focuses on heavy-duty FCEVs and their overall energetic efficiency enhancement by intelligently managing energy transfer across coolant circuit boundaries through waste heat recovery, while ensuring that all relevant components remain within required temperature boundaries under both cold and hot ambient conditions. Results were obtained using a 1D-model that comprises all thermal fluid circuits (refrigerant, coolant, air) created through GT-Suite software. This model was utilized to simulate heat distribution during various road transport missions, such as alpine crossing via Brenner Pass from Munich (Germany) to Modena (Italy). Depending on load cycle profile and ambient conditions significant fuel savings were demonstrated. Furthermore, by coupling the high-temperature circuit of the fuel cell with the low-temperature circuit of the battery via a water/water heat exchanger, there is no need for additional electric heating via an electric heating element (PTC) within this circuit. In more extreme ambient conditions, utilizing recovered heat solely from high-temperature fuel-cell circuit is not sufficient; thus, cabin heating (HVAC) requires further measures such as an additional PTC or system heat pump to achieve an acceptable pull-up time of the cabin.
Uhde, SophiaLanghorst, ThorstenWuest, MarcelNaber, Dirk
The document provides clarity related to multiple temperature coolant circuits used with on-highway and off-highway, gasoline, and light-duty to heavy-duty diesel engine cooling systems, or hybrid vehicle systems. These multiple temperature systems include engine jacket coolant plus at least one lower temperature system. Out of scope are the low temperature systems used in electric vehicles. This subject is covered in SAE J3073. Note that some content in SAE J3073 is likely to be of interest for hybrid vehicles. Out of scope are the terms and definitions of thermal flow control valves used in either low-temperature or high-temperature coolant circuits. This subject is covered in SAE J3142.
Cooling Systems Standards Committee
The high-performance electric sports cars market is expected to register rapid development in the next years, driven by a different attitude of racing enthusiasts toward electric vehicles. The improvements in battery technology are reinforcing consumer confidence and interest in electric sports vehicles, making them more attractive to enthusiasts and accelerating their adoption. Batteries have been used in high heat generation conditions more often with fast charging and discharging. Therefore, the need for more advanced battery thermal management systems (BTMS) has been increasing in recent years. Vegetable oil, owing to its unique availability and biodegradability, is considered as a viable alternative to fossil fuel-based cooling fluids in immersion cooling systems. In the present work, the feasibility of using vegetable oil in immersion cooling under high discharge conditions is studied by comparing it with four types of fossil fuel-based cooling fluids. Immersion cooling was applied to an 8S3P battery module, and the cooling performance of the battery module at high discharging rates was studied by using five different types of dielectric coolants. The immersion cooling model of battery module has been built, and the cooling performance with different types of coolants at high discharging rates (4C, 6C, and 8C) has been analyzed. The effect of coolant flow rate on battery cooling performance was also studied. To make a comprehensive evaluation on the coolants used for immersion cooling at high discharging rates, an analysis was conducted by assessing power consumption and temperature uniformity. Cooling efficiency, power consumption, and temperature uniformity were considered in coolant selection, and coolant flow rate had a significant effect on coolant selection. This study can provide a guidance for the design of BTMS with immersion cooling in electric vehicle applications.
Hong, HanchiSong, XiangShi, Xud’Apolito, LuigiXin, Qianfan
Improving electric vehicles’ overall thermal management strategy can directly or indirectly improve battery efficiency and vehicle range [1]. In this study, the effect of the coolant type used in BTMS (battery thermal management system) units used for heating batteries in cold weather conditions was investigated in electric buses. In this investigation, tests were performed with two types of antifreeze, which have different characteristics. The study evaluated the impact of coolant flow, BTMS circulation pump performance, and battery heating using these two types of antifreeze in the BTMS coolant line. In addition to carrying out tests, 1D computational fluid dynamics models’ simulations were carried out for both types of antifreeze, and the results were validated with experimental findings. In this study, a 12-m EV Citivolt vehicle of Anadolu Isuzu was used for tests. As a result, it was observed that differences in the properties of the antifreeze that is used in BTMS coolant line affected the coolant flow and BTMS heating performance in cold weather conditions.
Çetir, ÖzgürBirgül, Çağrı Emre
Efficient thermal management is essential for maintaining the performance and safety of large-capacity battery packs. To overcome the limitations of traditional standalone air or liquid cooling methods, which often result in inadequate cooling and uneven temperature distribution, a hybrid air-liquid cooling structure was designed. A three-dimensional model was developed, and heat transfer and fluid flow characteristics were analyzed using computational fluid dynamics (CFD) simulations. Experimental validation was carried out through discharge temperature rise tests on individual battery cells and flow resistance tests on the liquid cooling plate. The thermal performance of the hybrid system was compared to that of standalone cooling methods under various discharge rates. The results indicated that the hybrid system significantly enhanced cooling performance, reducing the maximum temperature difference by 5.54°C and 3.37°C, and the peak temperature by 11.66°C and 4.5°C, compared to air and liquid cooling, respectively, at a 0.8C discharge rate. The effects of key parameters, such as coolant flow rate, fan speed, channel width, and channel depth, on cooling performance were investigated. A turbulence-inducing structure was proposed to further improve cooling efficiency. The optimized system maintained peak temperatures and temperature differences below 35°C and 5°C, respectively, at a 0.5C discharge rate, with a reduction in pressure drop by 14.50 kPa. This study proposes an effective hybrid air-liquid cooling solution, providing valuable insights for the thermal management design of battery packs.
Li, HaoGuo, YimingZhou, FupengLi, KunyuanShangguan, Wen-Bin
Lithium-ion batteries (LIBs) are critical components in electric vehicles (EVs) and renewable energy systems. However, conventional cooling techniques for LIBs often struggle to efficiently dissipate heat during fast charging and discharging, potentially compromising performance and safety. This study investigates the thermal performance of immersion cooling applied to an Electric Vehicle (EV) battery module comprised of NCA-chemistry-based cylindrical 21700 format Lithium-ion cells. The effectiveness of immersion cooling in reducing maximum cell temperature, temperature gradient, cell-to-cell temperature differential, and pressure drop within the battery module is evaluated on a detailed 3D model of a 360-cell immersion-cooled battery module that was developed, incorporating a well-established heat generation model based on theoretical analysis and experimental data to simulate the thermal characteristics of the battery system. The effects of the different fluid properties are first assessed, resulting in higher heat transfer coefficients with lower fluid viscosity values and high specific heats. Density and thermal conductivity effects are also obtained. Subsequently, a set of different fluids are introduced into the model to obtain which one returned the best thermal performance. Results demonstrate that under transient operating conditions, such as a WLTP driving cycle, the temperature increase of the cells remains limited, resulting in minimal differences in performance between the tested fluids. However, under more demanding scenarios, such as fast charging and high C-rate, significant differences in thermal performance among the fluids emerge. These findings enhance our understanding of battery immersion cooling technology and provide novel insights for optimizing battery thermal management systems through computational fluid dynamics (CFD).
Garcia, AntonioMicó, CarlosMarco-Gimeno, JavierElkourchi, Imad
The operating temperature of lithium-ion battery (LIB) cells significantly influences their degradation behavior. In indirect liquid cooling systems, temperature variations within a Battery Electric Vehicle (BEV) LIB module are inevitable due to the increasing downstream temperature of the cooling medium as it absorbs heat. This leads to reduced temperature differentials between the cooling medium and the LIB cells. As a result, LIB cells located further along the flow path experience higher average temperatures than those at the front. Typically, a maximum average cell temperature difference of 5 K within LIB modules is considered acceptable. However, results from a conventional cooling system indicate that, when fast charging is exclusively used, this can lead to a 15.5 % difference in the total ampere-hours passed before the End-of-Life (EOL) is reached for the front and back LIB cells. To address this issue, a switchable thermal management system for the traction battery is proposed. In this concept, the coolant inlet flow direction is reversed after every fast charge. Compared to conventional systems, this flow direction switch can increase the total ampere-hours passed by 7.2 %, leading to a corresponding 7.2 % increase in vehicle range until the first cell reaches EOL. The concepts are evaluated using a validated 1D electro-thermal-aging model. Additionally, a 3D electro-thermal Computational Fluid Dynamics (CFD) model of a module section, including a wavy-mini-channel cooling design, is employed. Together, these approaches ensure that the 1D model accurately captures the thermal behavior of the LIB module cells.
Auch, MarcusWeyershäuser, KonstantinKuthada, TimoWagner, Andreas
This study investigates the impact of thermal imbalances on energy delivery and Battery State of Power (SoP) in immersion-cooled battery cells. It explores how these imbalances, which arise when cells within a module operate at different temperatures, lead to variations in internal resistance and inefficiencies in energy storage and discharge. Such imbalances critically affect the battery's SoP, representing the maximum charge or discharge power the system can support over specific time intervals. By analyzing SoP over 10-second durations and continuous, we assess how thermal imbalances influence both short-term and medium-term power capabilities. Temperature significantly impacts cell aging, and imbalances can accelerate degradation in some cells, ultimately affecting serviceability. To address these issues, we employ a high-level simulation framework that integrates advanced tools. GT-SUITE software optimizes thermal performance by adjusting coolant temperature and flow rate to manage thermal imbalances. Concurrently, Ansys software provides detailed thermal simulations, considering heat generation within cells and coolant dynamics. This integration uses a Functional Mock-up Unit (FMU) approach. A MATLAB/SIMULINK controller implements a degradation method, while an electrochemical model illustrates the effects of thermal imbalance on aging. Additionally, we introduce an electrical State of Charge (SOC)-based balancing method to dynamically redistribute electrical loads among cells, correcting imbalances in energy storage and discharge. This strategy aims to enhance energy distribution, improve SoP, reduce aging, and minimize internal resistance differences. The effectiveness of this comprehensive approach will be evaluated based on its impact on energy delivery efficiency, SoP stability over 10-second and continuous intervals, and the overall lifespan of the battery module, ultimately optimizing cooling parameters and enhancing performance and longevity.
Meshginqalam, AtaNegro, SergioAtluri, PrasadTyagi, RamavtarSuzuki, JorgeK B, AnjushaCao, Yuyuan
A method for performance calculation and experimental method of a high voltage heater system in electric vehicles is proposed. Firstly, heater outlet temperature and pressure drop of the heater are used as metrics to compare simulation results with experimental data, thereby validating the established model. Then, simulations are performed on two heater flow channel configurations: a cavity flow channel and a cooling fin flow channel. It is observed that the latter significantly reduces the heating plate temperature. This reduction enhances the protection of heating elements and extends their operational lifespan, demonstrating the advantages of incorporating cooling fins into the flow channel structure. The optimization variables for multi-objective optimization include the fin unit length, fin height, fin thickness, fin width, and spacing between two adjacent rows of fins. The optimization objectives include pressure drop, heat transfer efficiency, and heating plate temperature. Multiple sets of sample schemes comprising the variables are generated using the Latin hypercube sampling method. For each combination of variables, the objectives is estimated using Fluent software. Based on the estimated relations of variables versus objectives using the Latin hypercube sampling method, a response surface model is constructed. Finally, the MOGA algorithm is used to determine the optimal fin structure scheme. The optimization design results show that a significant reduction in pressure drop, heat transfer efficiency is enhanced, and heating plate temperature is reduced compared to the original model, confirming the effectiveness of the optimization.
Gong, MingWang, XihuiWang, DongdongShangguan, Wen-Bin
Ensuring uniform coolant distribution in electric buses is crucial for battery performance, longevity, and thermal stability. This study optimizes the battery thermal management system (BTMS) for an 18-m electric bus, addressing uneven coolant flow to battery packs caused by pressure drop variations. One-dimensional (1D) simulations were chosen for their ability to quickly and efficiently analyze flow and pressure variations, providing a fast solution to optimize coolant distribution across the system. dP-Q curves for the BTMS pump and battery packs were integrated into the 1D model based on supplier data, while the flow resistances of other components (pipes, bends) were calculated using KULI software. To correct flow imbalances, pipe diameters were adjusted to increase resistance in over-cooled areas, redistributing coolant to under-cooled sections. This modification resulted in a balanced flow and improved thermal consistency, contributing to longer battery life. Validation showed an 11% deviation between experimental and simulation results, confirming the system’s reliability. This study emphasizes the importance of precise flow management for enhancing battery life and provides a scalable solution for optimizing the thermal management of electric vehicles.
Birgül, Çağrı EmreMeydan, Ömer
With the rapid adoption of new energy vehicles (NEVs), effective thermal management has become a crucial factor for enhancing performance, safety, and efficiency. This study investigates the steady-state and dynamic characteristics of a secondary loop CO₂ (R744) thermal management system designed for electric vehicles. The secondary loop system presents several benefits, such as improved safety through reduced refrigerant leakage and enhanced integration capabilities with existing vehicle subsystems. However, these advantages often come at the cost of decreased thermodynamic efficiency compared to direct systems. Experimental evaluations were conducted to understand the effects of varying coolant flow rates, discharge pressure, and dynamic startup behaviors. Results indicate that while the indirect system generally shows a lower coefficient of performance (COP) than direct systems, optimization of key parameters like coolant flow rate and discharge pressure can significantly enhance performance. Specifically, optimizing the coolant flow rate resulted in a COP increase of up to 92.6% under certain conditions, while proper management of discharge pressure improved the heating capacity and system efficiency. Additionally, dynamic analysis of startup behaviors revealed the importance of effectively managing refrigerant distribution to achieve stable system operation and minimize energy losses. These findings provide valuable insights into the engineering feasibility and potential improvements of secondary loop systems. By focusing on the optimization of flow rate, pressure management, and startup control, this study supports the development of more sustainable and energy-efficient solutions for the thermal management of NEVs, ultimately contributing to the wider adoption of environmentally friendly transportation technologies.
Zong, ShuoHe, YifanGuan, YanDong, QiqiYin, XiangCao, Feng
A mathematical model of the thermal management system (TMS) for an extended-range hybrid electric vehicle is developed. The variation in engine coolant temperature is examined under different water pump and fan control strategies, and its subsequent impact on engine TMS energy consumption is analyzed. Based on the simulation results of energy consumption under various control parameters, machine learning regression models are constructed, and four different regression algorithms are applied. By incorporating temperature-based optimization into the water pump and fan control strategy, system energy consumption can be effectively reduced. The machine learning regression results indicate that the mathematical model of TMS cannot be simply regarded as a linear model. ANN and SVM regression show high degree of agreement with the mathematical model. This study provides a theoretical foundation for the development of data-driven tool for optimizing real-time TMS control strategies.
Pan, ShiyiZhang, NanZheng, JunliSun, TianfuZidi, Li
This paper addresses a series of issues in the thermal management system of proton exchange membrane fuel cells (PEMFC) during power fluctuations, such as slow system response, insufficient stability, significant temperature fluctuations, and the complexity of coupled control between coolant flow and air flow. A solution is proposed by designing separate Linear Active Disturbance Rejection Controllers (LADRC) for the coolant flow and air flow control loops. A one-dimensional model of the PEMFC thermal management system was established on the LMS AMESIM simulation platform, combined with a hydrogen fuel cell vehicle model and a driver model, fully considering various influencing factors such as vehicle power fluctuations and driver demands. Subsequently, the LADRC control algorithm was developed on the Matlab-Simulink platform, and a co-simulation analysis was performed to compare the control effects of PID control and LADRC under both custom operating conditions and the New European Driving Cycle (NEDC) conditions. The simulation results show that with the LADRC controller, the temperature of the coolant entering the stack can be stably maintained at 65°C, and the LADRC controller can quickly respond to temperature changes during drastic condition variations. Under NEDC conditions, when the power rapidly increases, the peak temperature of the coolant exiting the stack reaches 70.5°C, which is 3.55°C lower than the temperature under traditional PID control. Additionally, the fluctuation of temperature difference of the system is kept within 7°C.
Zhu, ShaopengMei, JingYang, LangZong, YajingLiu, YunmeiZhang, BoChen, Huipeng
Magnesium oxide (MgO) nanofluids are of great interest for enhancing the performance in thermal management especially in automotive applications, where efforts have been made to reduce parasitic losses from traditional cooling systems. These findings highlight the effects of Water–ethylene glycol and MgO nanofluids on viscosity and thermal conductivity in specific filling a gap in research that allows to clarify how these states behave at different temperature (T) and concentration (C) conditions. Test results demonstrate that the thermal conductivity of MgO nanofluids improved adequately /while its corresponding change in viscosity remained under control, affirming a significant improvement for energy savings by means heat transfer enhancement using new generation coolants based on this nano-additive. The results also provide useful information for design and development of automotive cooling systems, including real numbers on performance improvements that lead to more efficient and reliable thermal management designs.
Jeyanthi, P.
The aim of the article is to evaluate the effect of the cooling system on the NVH behavior of traction permanent magnets synchronous motors (PMSMs). An effective numerical method is proposed for modeling the fluid–structure interaction in the cooling system of PMSMs. A simplified physical prototype of a cooling jacket of a PMSM is realized by welding two concentric tubes with an internal cavity filled by coolant. A finite element model of the structure is realized. The coolant is modeled as an acoustic domain to account for the fluid–structure interaction in the cavity and a coupled acoustic–structural dynamic problem is solved. The model is validated by experimental modal tests conducted on the prototype of the cooling jacket both with and without the presence of coolant. The validated model is employed to quantify the effect of the cooling system on a real PMSM. The structure of a 10-poles, 12-slots electric machine is modeled by means of finite element method. The model includes the validated cooling jacket and the internal stator lamination and windings. Numerical vibroacoustic analyses have been performed at different operating conditions, either with or without modeling the coolant with the aim of quantifying its effect on the sound emission of the machine. Acoustic emission is generally increased when fluid coolant is present. For a PMSM, localized sound emission peaks appeared in the low-frequency range, up to 2000 Hz. A maximum increase of 44 dB was observed.
Barri, DarioSoresini, FedericoBallo, FedericoLucà, FrancescantonioManzoni, StefanoGobbi, MassimilianoMastinu, Giampiero
In this study, we investigate the thermal conductivity optimization of nanodiamond nanofluids for application in high-performance automotive engines. Nanodiamond particles, known for their superior thermal properties and stability, are dispersed in a base fluid composed of ethylene glycol and water. Various concentrations of nanodiamonds are prepared to evaluate their impact on thermal conductivity and viscosity. The experimental setup includes precise measurements of thermal conductivity using the transient hot-wire method and viscosity using a rotational viscometer over a temperature range of 25°C to 100°C. The results demonstrate significant enhancements in thermal conductivity with acceptable increases in viscosity, suggesting the potential of nanodiamond nanofluids in improving engine cooling efficiency. The study concludes with recommendations for future research to explore the long-term stability and performance of these nanofluids in real-world automotive applications.
Jeyanthi, P.Gulothungan, G.
Nanofluids have emerged as effective alternatives to traditional coolants for enhancing thermal performance in automotive applications. This study conducts a comparative analysis of the viscosity and thermal conductivity of ZnO and Cu hybrid nanofluids. Nanofluids were prepared with ZnO and Cu nanoparticle concentrations of 0.1%, 0.3%, and 0.5% by volume and were characterized over temperatures ranging from 25°C to 100°C. The results demonstrate that ZnO and Cu hybrid nanofluids achieve an increase in thermal conductivity by up to 22% and 28%, respectively, compared to the base fluid. Concurrently, the viscosity of these nanofluids increases by up to 12% at the highest concentration and temperature. This study addresses a critical research gap by investigating the combined effects of ZnO and Cu nanoparticles in hybrid nanofluids, an area that has been underexplored. By providing new insights into optimizing both thermal conductivity and viscosity, this research contributes to the development of more efficient cooling systems for automotive applications.
Sivasubramanian, M.Sundaram, V.Madhu, S.Saravanan, A.Vidhyalakshmi, S.
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