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The conjugate heat transfer, which effectively integrates the heat conduction within the solid metal block of the so-called Water Spider Geometry (WSG) configuration and the fluid domain within it, is computationally investigated in the present work, allowing an accurate representation of the temperature conditions at the solid-fluid interface. The WSG configuration represents a specially configured tube geometry that effectively reproduces the flow behavior observed in cooling channels associated with Internal Combustion (IC) engines. The inherent high flow unsteadiness potential of the WSG flow configuration, resulting from the complex flow guidance involving phenomena such as flow impingement, bifurcation, multiple deflections and flow confluence, requires the application of a model capable of capturing turbulence fluctuations.

The pressure of energy transition and sustainable development has driven the rapid development of new energy vehicles (NEVs). Lithium-ion batteries (LIBs) are extensively utilized in NEVs because of their higher energy density, lower self-discharge rate, and environmental friendliness. Nevertheless, at subzero temperature environments, the electrochemical performance and available energy of LIBs are severely reduced, exhibiting significant charging difficulties, lifespan degradation, and safety issues. This performance degradation can contribute to the operational difficulties and safety hazards of NEVs. The purpose of this article is to provide a review of the challenges and limitations faced by LIBs in subzero temperature environments, as well as the development of subzero temperature LIBs from the cell level to the system level. Additionally, viable solutions to heat the battery by increasing the internal temperature are introduced.

Despite the widespread adoption of lithium-ion batteries in various applications such as energy storage, concerns related to thermal management have been persisting, primarily due to the heat generated during their operation and the associated adverse effects on its efficiency, safety, and lifetime. Hence, the thermal characterization of lithium-ion batteries is essential for optimizing the layout of the battery cells for a pack design and the corresponding thermal management system. This study focuses on an experimental investigation of heat generation of Li-ion batteries under different operating conditions, including charge-discharge rates, ambient temperatures, states of charge, and compressive pressure. The experiments were conducted using a custom-designed multifunctional calorimeter, enabling precise measurement of the heat generation rate of the battery and the entropy coefficient. The measured results have shown a good match with the calculated heat generation rate.

Fast charging of traction batteries in passenger cars enables comfortable travel with electric vehicles, even over longer distances, without having to oversize the installed batteries for everyday use. As an enabling technology for fast charging, Kautex presents the implementation of 2-phase immersion cooling, where the traction battery serves as an evaporator in a refrigeration process. The 2-phase immersion cooling enables very high heat transfer rates of 3400 W/m^2*K and at the same time maximizes temperature homogeneity within the battery pack at optimal battery operating temperature. Thus, heat loads at charging rates of more than 6C can be safely and permanently managed by the battery thermal system. The cooling performance of 2-phase immersion cooling can also successfully suppress thermal propagation inside a thermoplastic battery housing.

Concerns about climate change have significantly accelerated the process of vehicle electrification to improve the sustainability of the transportation sector. Increasing the adoption of electrified vehicles is closely tied to the advancement of reliable energy storage systems, with lithium-ion batteries currently standing as the most widely employed technology. One of the key technical challenges for reliability and durability of battery packs is the ability to accurately predict and control the temperature of the cells and temperature gradient between cells inside the pack. For this reason, accurate models are required to predict and control the cell temperature during driving and charging operations. This work presents a set of procedures tailored to characterize and measure the thermal properties in li-ion cells and modules.

The main objective of this paper is to describe the design, analysis and testing of a novel method of insulating the combustion chamber, which is key for efficiency demonstration on a new class of internal combustion engine (ICE). A recuperated split cycle engine (RSCE) has unique demands for heat loss reduction. In particular during the combustion event, to minimize the heat losses is a must to achieve high efficiency. The insulation is provided by a metal plate that is assembled into the cylinder head to line the combustion chamber surface. The design has been focused on reducing heat transfer surface area and exploiting contact gap thermal resistance between the upper surface of the plate and the cylinder head, thus reducing heat wasted to the coolant circuit. In this paper, the plate requirements, functions, design, analysis and test results from a research and development (R&D) program of a heavy duty (HD) recuperated split cycle engine are reported.

Baking ovens in the automotive paint shop are crucial to ensuring quality of paint curing and hence meet the corrosion protection targets in manufacturing process. Ovens are also among the most energy consuming processes in the entire paint shop. With the onset of Electric Vehicle revolution, original equipment manufacturers focus heavily on light weighting resulting in significant design changes to the body in white (BIW). This presents a challenge of achieving accurate curing in the existing ovens designed for the current and past generations of vehicles Using Computational fluid dynamics (CFD), this research intends to present a solution by minimizing the need for prototyping for design changes. Lattice Boltzmann Method (LBM) based thermal simulations are used to predict the curing behaviour on the BIW surface. The LBM based conjugated heat transfer simulations consider turbulence using a Large-Eddy Simulation (LES) approach and Boussinesq approximation.

DHT hybrid transmission assembly control system discussed in this paper includes hydraulic control, hybrid mode switching control, shift control, dual motor control, clutch and motor thermal management. The hybrid mode is divided into four modes: the EV mode, the serial mode, the parallel mode and the launch mode. Hydraulic control includes torque-pressure conversion, clutch pressure kiss point adaption, clutch oil filling time adaption. Shift control includes shift type decision, shift sequence control, shift inertia process based on motor intervention. Thermal management includes clutch flow and motor flow distribution. Motor control include the current control, mode control and boost strategy of permanent magnet synchronous motor in dual hybrid system, which has good stability and robustness. Motor mode includes initialization mode, normal mode, fault mode, active discharge mode, power off mode.

Semiconductor devices in electric vehicle (EV) motor drive systems are considered the most fragile components with a high occurrence rate for open circuit fault (OCF). Various signal-based and model-based methods with explicit mathematical models have been previously published for OCF diagnosis. However, this proposed work presents a model-free machine learning (ML) approach for a single-switch OCF detection and localization (DaL) for a two-level, three-phase inverter. Compared to already available ML models with complex feature extraction methods in the literature, a new and simple way to extract OCF feature data with sufficient classification accuracy is proposed. In this regard, the inherent property of active thermal management (ATM) based model predictive control (MPC) to quantify the conduction losses for each semiconductor device in a power converter is integrated with an ML network.

The transition towards battery electric vehicles (BEVs) has increased the focus of vehicle manufacturers on energy efficiency. Ensuring adequate airflow through the heat exchanger is necessary to climatize the vehicle, at the cost of an increase in the aerodynamic drag. With lower cooling airflow requirements in BEVs during driving, the front air intakes could be made smaller and thus be placed with greater freedom. This paper explores the effects on exterior aerodynamics caused by securing a constant cooling airflow through intakes at various positions across the front of the vehicle. High-fidelity simulations were performed on a variation of the open-source AeroSUV model that is more representative of a BEV configuration. To focus on the exterior aerodynamic changes, and under the assumption that the cooling requirements would remain the same for a given driving condition, a constant mass flow boundary condition was defined at the cooling airflow inlets and outlets.

The target of the upcoming automotive emission regulations is to promote a fast transition to near-zero emission vehicles. As such, the range of ambient and operating conditions tested in the homologation cycles is broadening. In this context, the proposed work aims to thoroughly investigate the potential of post-oxidation phenomena in reducing the light-off time of a conventional three-way catalyst. The study is carried out on a turbocharged four-cylinder gasoline engine by means of experimental and numerical activities. Post oxidation is achieved through the oxidation of unburned fuel in the exhaust line, exploiting a rich combustion and a secondary air injection dedicated strategy. The CFD methodology consists of two different approaches: the former relies on a full-engine mesh, the latter on a detailed analysis of the chemical reactions occurring in the exhaust line.

Performances of battery electric vehicles (BEV) are affected by the thermal imbalance in the battery packs under driving cycles. BEV thermal management system (VTMS) should be managed efficiently for optimal energy consumption and cabin comfort. Temperature changes in the brick, module, and pack under the repeated transient cycles must be understood for model-based development. The authors conducted chassis dynamometer experiments on a fully electric small crossover sports utility vehicle (SUV) to address this challenge. A BEV is tested using a hub-type, 4-wheel motor chassis dynamometer with an air blower under the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) and Federal Test Procedures (FTP) with various ambient temperatures. The mid-size BEV with dual-motor featured 80 thermocouples mounted on the 74-kWh battery pack, including the cells, upper tray, side cover, and pack cover.

Per - and polyfluoroalkyl substances – known as PFAS are man-made chemicals that do not occur naturally. PFAS are widely used, long lasting chemicals, components of which break down very slowly over time. Scientific studies have shown that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals. Because of their widespread use and their persistence in the environment, many PFAS are found in human and animals’ blood all over the world and are present at low levels in a variety of food products and in the environment. PFAS are found in water, air, fish, and soil at locations across the nation and the globe. Both refrigerants (HFC-134a & HFO-1234yf) that are currently used in mobile air conditioning systems (MACS) create PFAS. Hence, various countries are looking into banning chemicals that create PFAS. Natural refrigerants are being proposed as alternative refrigerants as they do not create PFAS.

The degradation rate of a Li-ion battery is a complex function of temperature and charge/discharge rates over its lifetime. There is obviously a keen interest in predictive electrochemical ageing models that account for known degradation mechanisms, primarily linked with the Solid Electrolyte Interface (SEI) formation and Li-plating, which are highly dependent on the cell temperature. Typically, such ageing models are formulated and employed at pack or cell level, neglecting intra-cell and cell-to-cell thermal and electrical non-uniformities. On the other hand, thermal management techniques can mitigate ageing by maintaining the battery pack within the desired temperature window either by cooling or heating. Inevitably, the cooling of the battery pack by conventional heat exchangers will introduce temperature non-uniformities that may in turn result in undesired intra-cell and/or cell-to-cell health non-uniformities.

The growing global adoption of electric vehicles (EVs) emphasizes the pressing need for a comprehensive understanding of thermal runaway in lithium-ion batteries. Prevention of the onset of thermal runaway and its subsequent propagation throughout the entire battery pack is one of the pressing challenges of lithium-ion batteries. In addition to generating excess heat, thermal runaway of batteries also releases hazardous flammable gases, posing risks of external combustion and fires. Most existing thermal runaway models in literature primarily focus on predicting heat release or the total amount of vent gas. In this study, we present a model capable of predicting both heat release and the transient composition of emitted gases, including CO, H2, CO2, and hydrocarbons, during thermal runaway events. We calibrated the model using experimental data obtained from an 18650 cell from the literature, ensuring the accuracy of reaction parameters.

With the increasing demand for Battery Electric Vehicles (BEVs) capable of extended mileage, optimizing their efficiency has become paramount for manufacturers. However, the challenge lies in balancing the need for climate control within the cabin and precise thermal regulation of the battery, which can significantly reduce a vehicle's driving range, often leading to energy consumption exceeding 50% under severe weather conditions. To address these critical concerns, this study embarks on a comprehensive exploration of the impact of weather conditions on energy consumption and range for the 2019 Nissan Leaf Plus. The primary objective of this research is to enhance the understanding of thermal management for BEVs by introducing a sophisticated thermal management system model, along with detailed thermal models for both the battery and the cabin.

Due to the global drive for carbon neutrality, passenger vehicle gasoline engines are transitioning to higher levels of electrification, such as hybrid electric vehicles and plug-in hybrid electric vehicles, HEVs and PHEVs. Compared with conventional internal combustion engine (ICE) vehicles, the HEV or PHEV engine whilst in ICE only operation, typically operates for multiple shorter periods, in turn the engine coolant and lubricant temperatures are lower. Conventional internal combustion engines are often able to yield valuable fuel economy benefits by selecting appropriate engine lubricating oils, typically employing reduced viscosity and suitable additives. There are commercial engine tests available for measurement, often in an engine test cell for precision. Steady state testing is also a simplified option. Such efforts require care, as the accurate measurement is technically and practically challenging.

Hydrogen Internal Combustion Engines (H2 ICE) are gaining recognition as a nearly emission-free alternative to traditional ICE engines. However, H2 ICE systems face challenges related to thermal management, N2O emissions, and reduced SCR efficiency in high humidity conditions (15% H2O). This study assesses how hydrogen in the exhaust affects after-treatment system components for H2 ICE engines, such as Selective Catalytic Reduction (SCR), Hydrogen Oxidation Catalyst (HOC), and Ammonia Slip Catalyst (ASC). Steady-state experiments with inlet H2 inlet concentrations of 0.25% to 1% and gas stream moisture levels of up to 15% H2O were conducted to characterize the catalyst response to H2 ICE exhaust. The data was used to calibrate and validate system component models, forming the basis for a system simulation.

The high-efficiency dedicated hybrid engine (DHE) has led to increasingly complex challenges in engine thermal management. On one hand, the high compression ratio of up to 16:1 makes the engine more susceptible to knocking, necessitating meticulous thermal management to mitigate the potential sensitivity to metal temperature. On the other hand, extensive use of external cooled exhaust gas recirculation (EGR) helps reduce knocking and improve thermal efficiency, but it also raises temperature levels and requires additional cooling measures. For the 1.5L DHE developed by SAIC Motor, a split cooling structure was employed in the engine cooling system design, with the cylinder head water jacket and cylinder block water jacket arranged in parallel and equipped with different coolant outlets. By utilizing a dual thermostat to control flow, this design allows for adjustable flow distribution, providing effective cooling to the cylinder head while reducing cooling to the cylinder block.

Turbulent jet ignition (TJI) combustion using pre-chamber ignition can accelerate the combustion speed in the cylinder and has garnered growing interest in recent years. However, it is complicated for the optimization of the pre-chamber structure and combustion system. This study investigated the effects of the pre-chamber structure and the intake ports on the combustion characteristics of a gasoline engine through CFD simulation. Spark ignition (SI) combustion simulation was also conducted for comparison. The results showed that the design of the pre-chamber that causes the jet flame colliding with walls severely worsen the combustion, increasing the knocking intendency, and decrease the thermal efficiency. Compared with SI combustion mode, the TJI combustion mode has the higher heat transfer loss and lower unburned loss. The well-optimized pre-chamber can accelerate the flame propagation with knock suppression.