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Abstract This article proposes a disturbance observer-based event-triggered H ∞ controller for a semi-active seat suspension that equips an advanced electromagnetic damper (EMD) system. Automated driving is one of the leading technologies of the automotive industry. However, automated vehicles (AVs) may increase the incidence of motion sickness (MS) and deteriorate motion comfort. This article investigates a semi-active seat suspension system and an advanced controller to improve the motion comfort of AVs. The disturbance force of the seat suspension has considerable influence on the system dynamic, and applying a constant model to describe the real-time disturbance force is unreliable. Therefore, a disturbance observer is designed to estimate the seat suspension disturbance force, and it is used to compensate the controller. The Bouc-Wen model is selected to compare with the disturbance observer and validate its effectiveness.

Abstract Single point incremental forming (SPIF) is a sheet forming technology giving low volume production with high flexibility characteristics. The flexibility of the process is mainly related to the fact that incremental forming does not require a dedicated die to operate as compared to other forming processes. Polymers are extensively used for many applications because of their good mechanical properties. Considerable research has been reported for the SPIF of metals, but the researches on polymers are in scarce. In the present work, SPIF is performed on one of the polymers known as polyvinyl chloride. The effect of wall angle, feed rate, and step size on springback, thinning, and surface roughness is observed. It was found that the springback mainly depends on the wall angle but it is least dependent on the feed rate. The thinning and the surface roughness also mainly depend on the wall angle but are least dependent on step size.

Abstract Contemporary research has found differences between demographic groups in their stated instrument cluster component design preferences. For instance, elderly drivers prefer large icons and textual displays of information, while younger drivers preferred gauges to display information. The purpose of this study was to evaluate whether instrument clusters, designed for specific demographic groups, would facilitate safe driving behavior and solicit higher evaluation scores in their targeted demographics. Fifty participants, consisting of 30 elderly and 20 younger drivers (gender-balanced), completed a series of tasks to retrieve information from the instrument cluster while driving a high-fidelity simulator. Participants’ driving behavior, response time, subjective ratings, and a semi-structured post-experimental interview on different cluster designs were collected to evaluate each instrument cluster design.

Abstract The main aim of this study is to understand the effect of thermal conditions on the fatigue resistance of one automotive Daytime Running Lamp (DRL) housing made of Polycarbonate (PC) material. Automotive lighting products are made of mostly thermoplastic materials. Thermoplastic materials have mechanical properties varying significantly by temperature. As a result, thermal conditions at service life must be considered before evaluating the mechanical performance of automotive lighting products. In this study, thermal finite element analysis (FEA) has been done in order to understand the temperature distribution on DRL components at different thermal environments. Thermal map files representing the temperature distributions of the DRL components have been extracted and entered as load inputs into the modal FEA to find out the resonance frequencies. Using material properties varying by temperature, resonance frequencies of the DRL have been found by modal analysis and compared.

Abstract The civil aircraft nosewheel is clamped, lifted, and retained through the pick-up and holding system of the towbarless towing vehicle (TLTV), and the aircraft may be moved from the parking position to an adjacent one, the taxiway, a maintenance hangar, a location near the active runway, or conversely only with the power of the TLTV. The TLTV interfacing with the nose-landing gear of civil transport aircraft for the long-distance towing operations at a high speed could be defined as a towbarless aircraft taxiing system (TLATS). The dynamic loads induced by the system vibration may cause damage or reduce the certified safe-life limit of the nose-landing gear or the TLTV when the towing speed increases up to 40 km/h during the towing operations due to the maximum ramp weight of a heavy aircraft.

Abstract We recently developed a three-direction (vertical, longitudinal, and lateral) coupled biodynamic model of seated posture under vibration. However, in that study we only tested one algorithm to identify the model parameters. This article investigates four different optimization solvers in Matlab®, i.e., particle swarm optimization (particleswarm), particle swarm and local optimization method (fmincon), genetic algorithm (ga) and local optimization method (fmincon), and local optimization method (fmincon) to identify coupled biodynamic model parameters. Based on the obtained parameters, it further compares experimental and simulation results to determine the best optimization solver in terms of the root mean square error (RMSE), linear regression (R 2), goodness of fit (ε), and CPU time. The results show that particle swarm optimization is the best one for identifying the biodynamic model’s parameters.

Abstract The optimal negative stiffness structures and the hydraulic mounts used to replace the driver’s seat traditional suspension system and cab’s traditional rubber mounts of the soil compactors are proposed to enhance the driver’s ride quality and control the cab shaking. A nonlinear dynamic model with 7 degrees of freedom of the vehicle is established to analyze the ride quality under various operating conditions of the vehicle moving and working on off-road terrains. The root mean square values of the driver’s seat displacement, driver’s seat acceleration, and cab pitch’s acceleration are chosen as the objective functions. The investigation results show that both the optimal negative stiffness structures and the hydraulic mounts used on the driver’s seat suspension and cab isolation system greatly improve the driver’s ride quality and control the cab shaking under all the different operating conditions of the vehicle.

Abstract This study proposes three different models, the negative stiffness structure (NSS), damping structure (DS), and a combination of NSS and DS (NSDS), for the traditional seat suspension (TSS) of the vibratory roller to improve the driver’s ride comfort. A dynamic model of the vibratory roller established under the condition of the vehicle working on an elastoplastic soil with poor terrain surface is used to assess the performance of the NSS, DS, and NSDS. The sensitivity effect of the design parameters of the NSS, DS, and NSDS on their isolation efficiency is analyzed using the indexes of the root mean square (RMS) of the driver’s seat displacement (zws ) and acceleration (aws ). The design parameters of the NSS, DS, and NSDS are then optimized based on the multi-objective optimization method to fully evaluate their isolation efficiency. Finally, the experimental study is carried out on the vibratory roller to verify the research results.

Abstract Heating, ventilation, and air-conditioning (HVAC) systems can have a significant impact on the driving range of battery electric vehicles (BEVs). In our previous work, high-fidelity Computational fluid dynamics (CFD) simulations, validated against climatic wind tunnel measurements, were coupled with machine learning (ML) algorithms to predict vehicle occupant thermal comfort for any combination of glazing properties for any window surface, environmental conditions, and HVAC settings (flow rate and discharge air temperature). In the present study, the input feature space was expanded significantly to include climate seats (heated/cooled), heated steering wheel, radiant heating pads, and airflow direction from the air-conditioning (A/C) vents. The modified vehicle cabin CFD model, which included these additional features, was used to generate steady-state training and test data.

Abstract Turbulent jet ignition (TJI) is a pre-chamber initiated combustion technology that has been demonstrated to provide low temperature, faster burn rate combustion of lean and intake charge diluted air-fuel mixtures. Dual mode turbulent jet ignition (DM-TJI) is a novel concept wherein a separate air supply is provided for the pre-chamber apart from the conventional auxiliary fuel as supplied for TJI systems. The current study aims to extend the lean flammability limit of a gasoline-fueled engine using DM-TJI. Ignition delay time and combustion behavior of ultra-lean iso-octane/air mixture (Lambda ≅ 3.0) was studied using a TJI-based optically accessible rapid compression machine. High-speed fuel spray recordings in the pre-chamber were obtained using borescope imaging setup. Images of the reacting turbulent jet and subsequent combustion in the main chamber were captured using a visible color camera.

Abstract Upcoming engine generations are characterized by both a general trend of increased specific-power and higher efficiency. This leads to increased thermal loads, compromising reliability, and simultaneously to a limited amount of heat under ordinary engine use. Heat is a valuable resource in providing passenger comfort and emission control. For these reasons the subject of engine thermal management is receiving increasing attention. This work presents a comprehensive study of the complete engine thermal behavior at relevant running conditions: rated-power, peak-torque and ordinary use. The work is further extended to the engine warm-up period. The result is a high-resolution complete engine thermal model, capable of simultaneously reporting the local temperature of any engine part, and the global engine heat balance at any engine load.

Abstract With the reduction in PM emission standards for light duty vehicles to 3 mg/mi for current Federal and California standards and subsequently to 1 mg/mi in 2025 for California, the required PM measurements are approaching the detection limits of the gravimetric method. A “filter survey” was conducted with 11 laboratories, representing industry, agencies, research institutes, and academic institutions to analyze the accuracy of the current gravimetric filter measurement method under controlled conditions. The reference filter variability, measured within a given day over periods as short as an hour, ranged from 0.61 μg to 2 μg to 5.0 μg for the 5th, 50th, 95th percentiles (n > 40,000 weights, 317 reference objects), with a laboratory average of 2.5 μg.

Abstract Turbocharging can provide a low cost means for increasing the power output and fuel economy of an internal combustion engine. Currently, turbocharging is common in multi-cylinder engines, but due to the inconsistent nature of intake air flow, it is not commonly used in single-cylinder engines. In this article, we propose a novel method for turbocharging single-cylinder, four-stroke engines. Our method adds an air capacitor-an additional volume in series with the intake manifold, between the turbocharger compressor and the engine intake-to buffer the output from the turbocharger compressor and deliver pressurized air during the intake stroke. We analyzed the theoretical feasibility of air capacitor-based turbocharging for a single-cylinder engine, focusing on fill time, optimal volume, density gain, and thermal effects due to adiabatic compression of the intake air.

Abstract Concerns about tire noise radiation arise partly from city traffic planning, environmental protection, and pedestrian safety standpoints, while from the vehicle passengers’ perspective, noise transmitted to the vehicle interior is more important. It is the latter concern that is addressed in this article. Sound-absorbing materials generally offer good absorption at higher frequencies, but the reduction of relatively low frequency, structure-borne tire noise is a continuing focus of many auto manufacturers. A tire’s internal, acoustic cavity resonance is a very strong contributing factor to tire-related structure-borne noise, and it can easily be perceived by passengers. Some reduction of vehicle cabin noise can be achieved through the insertion of sound-absorbing material in the tires. However, apart from the additional cost for such tires, there is also an increased complexity when repairing them because of the need to avoid damaging the sound-absorptive lining.

Abstract Li-ion batteries have been widely applied in the areas of personal electronic devices, stationary energy storage system and electric vehicles due to their high energy/power density, low self-discharge rate and long cycle life etc. For the better designs of both the battery cells and their thermal management systems, various numerical approaches have been proposed to investigate the thermal performance of power batteries. Without the requirement of detailed physical and thermal parameters of batteries, this article proposed a data-driven model using the adaptive neuro-fuzzy inference system (ANFIS) to predict the battery temperature with the inputs of ambient temperature, current and state of charge. Thermal response of a Li-ion battery module was experimentally evaluated under various conditions (i.e. ambient temperature of 0, 5, 10, 15 and 20 °C, and current rate of C/2, 1C and 2C) to acquire the necessary data sets for model development and validation.

Abstract Thermoelectric devices (TEDs) allow direct electric and thermal energy mutual conversion. Because of the absence of working fluids and moving components, they can be used where it is not possible to refer to conventional technologies. In automotive applications, TEDs can give support in air conditioning and internal combustion engine (ICE) thermal heat recovery, contributing to increase the overall vehicle efficiency. Phenomena taking place in these devices are of a different nature and involve electric, thermal, and thermoelectric aspects, being highly influenced by materials’ characteristics and by system geometry. With the aim to offer a design tool, a TED mathematical model is presented in this article. The proposed model is based on a distributed parameter approach and has been conceived to consider heat transfer actual conditions. It accurately describes thermal energy production and removal terms due to Peltier and Joule effects.

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 Internal combustion (IC) engines are widely used in automotive, marine, agricultural and industrial machineries because of their superior performance, high efficiency, power density, durability and versatility in size and power outputs. In response to the demand for improved engine efficiency and lower CO2 emissions, advanced combustion process control techniques and more renewable fuels should be adopted for IC engines. Lean-burn combustion is one of the technologies with the potential to improve thermal efficiencies due to reduced heat loss and higher ratio of the specific heats. In order to operate the IC engines with very lean air/fuel mixtures, multiple turbulent jet pre-chamber ignition has been researched and developed to extend the lean-burn limit. Turbulent Jet Ignition (TJI) offers very fast burn rates compared to spark plug ignition by producing multiple ignition sites that consume the main charge rapidly.

Abstract This work presents a generalized methodology for the optimal thermal management of different powertrain devices. The methodology is based on the adoption of an electrically driven pump and on the development of a specifically designed controller algorithm. This is achieved following a Model Predictive Control approach and requires a generalized lumped-parameters model of the thermal exchange between the device walls and the coolant. The methodology is validated at a test rig, with reference to a four-cylinder spark-ignition engine. Results show that the proposed approach allows a reduction in fuel consumption of about 2-3% during the engine warm-up, a decrease in fuel consumption of about 1-2% during fully warmed operation, and an estimated fuel consumption reduction of about 2.5-3% in an NEDC. Finally, the investigation highlights that the proposed approach reduces the risk of after-boiling when the engine is rapidly switched off after a prolonged high-load operation.

Abstract The Engine Combustion Network case Spray A with a high-pressure fuel injection is at typical operating conditions of Diesel engines. Detailed pieces of information on this experiment are available, which supports a high-fidelity Large Eddy Simulation (LES) with real fluid thermodynamics. An internal injector flow simulation with the needle movement measured during the experiments is used to provide a realistic boundary condition for the fuel spray simulation. Two spray simulations have been conducted: one with a constant velocity profile and one with the velocity distribution obtained from a separate injector internal flow simulation. Peculiar emphasis is placed on the velocity and turbulence distribution to quantify the influence of spray inlet boundary conditions. The fuel injection is modeled with a single-phase approach applying adequate resolution to capture phase boundaries.