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Abstract Due to the limitations of current battery manufacturing processes, integration technology, and operating conditions, the large-scale application of lithium-ion batteries in the fields of energy storage and electric vehicles has led to an increasing number of fire accidents. When a lithium-ion battery undergoes thermal runaway, it undergoes complex and violent reactions, which can lead to combustion and explosion, accompanied by the production of a large amount of flammable and toxic gases. These flammable gases continue to undergo chemical reactions at high temperatures, producing complex secondary combustion products. This article systematically summarizes the gas generation characteristics of different types and states of batteries under different thermal runaway triggering conditions. And based on this, proposes the key research directions for the gas generation characteristics of lithium-ion batteries.

Abstract A novel method of measuring the thickness of deposits on engine pistons, including within ring grooves, is described. A laser profilometer is used in conjunction with a rotary stage to measure a continuous profile of the piston with deposits, and the measurement is repeated after cleaning the deposits from the piston. Algorithms for aligning the scans and determining the differential thickness are described, and results are compared to deposit thickness measurements using a contact-type magnetic induction coating thickness gauge. This method allows continuous measurement of deposit thickness across the entire surface including lands and ring grooves as well as quantification of the volume of the deposits.

Abstract An aeroengine exhaust plume is one of the important sources of infrared (IR) signature in the 3-5 μm and the 2-3 μm bands. Analysis, characterization, and modeling of the exhaust plume IR emission are needed for insight into its role in aircraft survivability against IR-guided missiles. The IR signature estimation of aeroengine exhaust needs estimation of radiative properties of absorbing-emitting exhaust gases, e.g., carbon dioxide (CO2) and water vapor (H2O). The radiative properties of the gases can be estimated by a mathematical model with a spectroscopic database of these gases. Low-Resolution Transmission (LOWTRAN), Moderate-Resolution Transmission (MODTRAN), High-Resolution Transmission (HITRAN), and High-Temperature Transmission (HITEMP) are some commonly used spectroscopic databases. This study compares Statistical Narrowband (SNB) models with the various other mathematical models used for the estimation of radiative properties of exhaust gases.

Abstract Biodiesel was found to be the best candidate to replace diesel fuel mainly due to being renewable, biodegradable, and non-toxic and reduce greenhouse gases, which cause global warming. Nowadays, biodiesel is blended with diesel fuel in different concentrations depending on the country of usage and is used in diesel engines. Concerns about biodiesel were raised after premature fouling of fuel filters were reported before meeting their mileage requirement. Three filters from Brazil were analyzed using different techniques (Energy Dispersive X-Ray [EDX], Fourier Transform Infrared Spectroscopy [FTIR], Thermogravimetric Analysis [TGA], Time of Flight-Secondary Ion Mass Spectrometry [ToF-SIMS], and Gas Chromatography/Mass Spectrometry [GC/MS]) to understand the chemical composition of the filter deposits and highlight the main compounds responsible for the blockage.

Abstract This article aims to analyze different six-phase winding configurations with rectangular bar wires to be used in an interior permanent magnet machine for an electrified vehicle application. Rectangular bar wires allow a higher slot fill factor compared to conventional round wires, and they are currently utilized in wave windings in the traction motors of commercial electrified vehicles. Combining bar wire winding with a six-phase configuration can lead to achieving a higher power density and more reliable operation in a traction motor. However, applying bar wires for a six-phase operation may raise further complications in the winding design, which requires special care to prevent complexities and potential failure points. In this article, the full-pitch wave winding pattern is discussed and then utilized for the implementation of pure six-phase and dual three-phase windings.

Abstract Recently, permanent magnet (PM)-assisted reluctance (PMAREL) machines are gaining increasing attention for traction applications to reduce magnet consumption. In this article, a comprehensive design methodology is applied to design a PMAREL machine for an electric vehicle (EV) propulsion application. The design method includes both electromagnetic and mechanical analyses. A finite element analysis (FEA)-based differential evolution (DE) algorithm is adopted to find the best reluctance (REL) rotor geometry. The PM dimensions are calculated analytically, which allows a fast identification for the initial design. An FEA model for mechanical analysis is developed, and some remedial techniques are adopted to improve the mechanical stress. The design procedure starts with the selection of the stator split ratio. Then it continues with REL optimization and PM dimension determination.

Abstract This article concerns the geometric optimization of permanent magnets motor structures using Finite Element software. The methodology is based on back electromotive force shape optimization for the reduction of the motor ripple torque. This study is based on two steps: firstly, the pre-dimensioning of the motor structures using the analytical method and, secondly, optimization of the geometry of the studied motor structures through the finite element method since the shape of the back electromotive forces strongly depend on the geometry of the motor structure such as the width of the magnets. Simulation results based on a parameterized finite element model show the performance of the study and its influence on the motor performance such as ripple torque.

Abstract In order to maximize the reluctance torque component, multiple-layer flux barriers are usually employed in permanent magnet-assisted synchronous reluctance (PMAREL) motors. However, the permanent magnet (PM) dimension of each layer should be carefully designed to achieve the best performance with the minimum PM material. This article investigates this issue and proposes a method to define the PM width according to the sinusoidal no-load airgap flux density distribution. First, the accuracy of the no-load magnetic circuit for airgap flux density calculation is verified with finite element analysis (FEA), considering single or multiple flux-barriers per pole. The effects of the location, width, and thickness of the PM are investigated separately. Then the PM width is derived by the equations developed from the no-load magnetic circuit. The proposed method reduces both the PM mass and the torque ripple.

Abstract Sustainable practices are taking precedence across many industries, as evident from their shift towards the use of environmentally responsible materials, such as natural fiber-reinforced acrylated epoxidized soybean oil (NF-AESO). However, due to the lower reactivity of AESO, the curing reaction usually requires higher temperatures and longer curing time (e.g., 150°C for 6-12 h), thus making the entire process unsustainable. In this study, we demonstrate the potential power of photons towards manufacturing NF-AESO composites in a sustainable manner at room temperature (RT) within 10 min. Two photoinitiators, i.e., the 2,2-dimethoxy phenylacetophenone (DMPA) and 1-hydroxycyclohexyl phenyl ketone (HCPK), were evaluated and compared with the thermal initiator, i.e., tert-butyl perbenzoate (TBPB). Based on the mechanical performance of the AESOs, the photoinitiation system for NF-AESO was optimized.

Abstract The aim of this article is to analyze the energy recovery of synthesis gases in an internal combustion engine, in terms of both their general behavior and recommendations for their future composition in production. This article presents an experimental analysis of power and economical parameters of internal combustion engine as a source of propulsion for a cogeneration unit. The power parameters were measured using 13 various low-energy synthesis gases as fuels. Most of them are methane-free synthesis gases. The main components of these synthesis gases were hydrogen, carbon monoxide, methane, carbon dioxide, and nitrogen. The composition of the synthesis gases responded to various waste gasification technologies. The mass lower heating value of the selected synthesis gases ranged from 4 to 8 MJ/kg.

Abstract Engine oils have complex packages of additives aimed at improving their tribological properties. However, interactions between elements of these additives may hinder the cooling ability of these oils. The current article addresses the influence of the interaction between chemical elements of oil additives on the cooling capacity of oils for different wall superheats (0°C-150°C) and oil bulk temperatures (60°C, 100°C, and 150°C). A back-propagation neural network (BPNN) is used to conduct the present work. The NN is trained on experimental heat transfer data of five commercial engine oils. Enhancement intensity, interaction sensitivity, and interaction stability of additive elements are investigated for the range of element concentrations of the experimental dataset.

Abstract Epoxies, synthesized from bisphenol-A (BPA) and epichlorohydrin (ECH), are predominantly used as coatings, adhesives, and matrix material in fiber-reinforced composites for body-in-white (BiW) applications in the automotive sector. However, given the production of conventional epoxies from nonrenewable petroleum resource and toxicity of BPA, several initiatives have been undertaken by researchers to synthesize alternative epoxies from various bio-sources that are free of BPA and exhibit similar mechanical performance. As a result, such bio-sourced epoxies are almost immediately termed as “ecofriendly,” despite the lack of comprehensive evaluation of their ecological performance that takes into account enhanced natural resource usage and associated impacts accompanying such epoxies.

Abstract The purpose of this article is to study the antifriction and anti-wear effect of GCr15 bearing steel under paraffin base oil and the base oil with two additives of T405 sulfurized olefin and nano-MoS2 and compare the synergistic lubrication effect of two different additives (MoS2 and T405) in paraffin base oil. The tribological properties of GCr15 bearing steel under different lubrication conditions were tested on a ball-on-disk tribometer. The three-dimensional profile of disk’s worn surfaces and the scanning electron microscope (SEM) micrographs of corresponding steel balls were analyzed at the same time. The wettability of lubricating oils on the surface of friction pairs and the dispersibility of MoS2 in base oil were characterized.

Abstract Metal Pick-Up (MPU) is a problematic phenomenon in automotive disc brakes. MPU generally forms as some metal lumps on the surface of the brake pad. If brake pads have MPU, during braking they would cause grooving of the disc rotor, generating brake noise and deteriorating the performance of the brake. The previous literature has so far reported that the source of the MPU is an Fe component from a disc rotor or brake pads. However, only a few of the generation mechanisms of MPU have been proven. We investigate MPU to completely elucidate the mechanism of MPU generation by using different analyses than the previous literature. First, to find out the source of MPU generation, we focus on the chemical reaction of a certain component with wear debris during braking, and some of the verification experiments are conducted under the conditions of simulated friction interface.

Engineering plastics are widely used in many tribological applications due to their inherent advantages such as reduced weight, ease of manufacturing, improved chemical compatibility, and damping characteristics. However, the process of selecting an appropriate polymeric material system for a specific application involves significant experimentation.

Abstract Automotive interior coatings for flexible and rigid substrates represent an important segment within automotive coating space. These coatings are used to protect plastic substrates from mechanical and chemical damage, in addition to providing colour and design aesthetics. These coatings are expected to resist aggressive chemicals, fluids, and stains while maintaining their long-term physical appearance and mechanical integrity. Designing such coatings, therefore, poses significant challenges to the formulators in effectively balancing these properties. Among many factors affecting coating properties, the cross-link density (XLD) and solubility parameter (δ) of coatings are the most predominant factors.

Abstract In this paper, the results of experiments to determine the effects of silicon-containing compounds in biogas on the performance of spark-ignited gas engines for use in CNG vehicles are presented. Initial research was performed on micro-CHP units, which have many features common with automotive engines, to identify engine components sensitive for silica deposition prior to investigating a practical CNG engine. The experiments on the micro-CHP units revealed that the catalyst was the most sensitive part for silica fouling, with strong impact on the reduction of NOx. With the insight gained from these experiments, an 9-week endurance test was performed on a light-duty CNG vehicle.

Abstract The use of nanomaterials and nanostructures have been revolutionizing the advancements of science and technology in various engineering and medical fields. As an example, Carbon Nanotubes (CNTs) have been extensively used for the improvement of mechanical, thermal, electrical, magnetic, and deteriorative properties of traditional composite materials for applications in high-performance structures. The exceptional materials properties of CNTs (i.e., mechanical, magnetic, thermal, and electrical) have introduced them as promising candidates for reinforcement of traditional composites. Most structural configurations of CNTs provide superior material properties; however, their geometrical shapes can deliver different features and characteristics. As one of the unique geometrical configurations, helical CNTs have a great potential for improvement of mechanical, thermal, and electrical properties of polymeric resin composites.