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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 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 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 A vehicle may be a font of data for some applications in safety, maintenance, and entertainment systems, once its electronic control units are connected to each other by a Controller Area Network (CAN) bus. By plugging a compatible device on the vehicle onboard diagnostics interface, reading raw data or conducting automotive diagnostics by International Standardization Organization 15765 and Society of Automotive Engineers J1979 is possible. The usual low-cost CAN data acquisition devices do not allow the connection to a cloud service for remote monitoring. Looking at this issue, this work proposes a low-cost NodeMCU CAN shield for data acquisition which is able to read the CAN frame of a Steering Angle Sensor, in Scenario 1, and standardized information from a vehicle such as its speed, identification number, and engine coolant temperature by automotive diagnostics, in Scenario 2.

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 In the last years, new stringent emission legislation in terms of nitrogen oxides (NOx) has been leading to a massive development of advanced after-treatment systems for diesel engines. Among them, selective catalytic reduction (SCR) technology has proved to be an effective approach for NOx reduction in a wide range of engine operating conditions. In SCR systems, the interaction between diesel exhaust fluid (DEF) and hot exhaust gas is crucial to promote the chemical reactions through which ammonia is produced. Hence, a proper matching between the exhaust pipe architecture and the DEF spray is mandatory for obtaining an adequate SCR efficiency, especially in close-coupled configurations and moderate exhaust gas temperature conditions. To this end, significant benefits could be derived via appropriate SCR injector thermal management, as the spray structure is significantly influenced by the DEF temperature upstream of the injector nozzle.

Abstract In this research, an integrated driving and braking control unit was developed for electric bikes. The unit integrates the driving and braking circuits in a module. Alternate commutation was used to design the driving and braking unit of a customized brushless direct-current hub motor (BLDCHM). The braking torque for the braking section is generated through alternating the duty cycle of the pulse-width-modulated (PWM) commands of the switching elements and phase sequence arrangement of the current conduction loops. The current conduction loops in the motor and switching elements is arranged to adjust the braking torque in a sophisticated way. The integrated design has been successfully tested in a commercialized electric bike with a BLDCHM.

Abstract Objectives: The project goal was to create an initial set of standardized tests to explore whether they enable the ongoing evaluation of automated driving features as they evolve over time. These tests focused on situations that were representative of several daily driving scenarios as encountered by lower-level automated features, often called Advanced Driver Assistance Systems (ADAS), while looking forward to higher levels of automation as new systems are deployed. Methods: The research project initially gathered information through a review of existing literature about ADAS and current test procedures. Thereafter, a focus group of industry experts was convened for additional insights and feedback. With this background, the research team developed a series of tests designed to evaluate a variety of automated driving features in currently available implementations and anticipated future variants.

Abstract In this work, a three-phase integrated onboard battery charger is investigated and implemented for electric vehicle (EV) applications. A three-switch add-on interface is introduced to connect with the inverter and the motor windings, such that a two-channel interleaved boost converter is formed for the battery charging. The detailed system analysis, design methodology, and control strategy are discussed. Moreover, a simulation study is carried out to validate the effectiveness of the proposed integrated charger. As verification, a 5 kW liquid-cooled prototype is built and tested. The proposed integrated charging system achieves a power factor of 0.99, and total harmonic distortion (THD) of 4.82% at 5 kW with an efficiency of 93.2%.

Abstract Current advances in connected and automated mobility claim to change driving scenarios worldwide. Nevertheless, the impact of automated mobility on the design of vehicle powertrains still need exhaustive assessment. In this article, a design methodology is proposed for BEV powertrains that integrates the consideration of vehicle-to-vehicle (V2V) connected driving. Particularly, each analyzed design solution is evaluated in standard drive cycles both as normal human-operated vehicle and as following car in automated V2V driving. The overall battery energy consumption for the latter case is evaluated by solving an optimization problem to determine off-line the most suitable vehicle speed trajectory. Remaining design requirements include vehicle maximum speed, acceleration capability, and gradeability. Obtained results aim at quantifying the amount of energy savings for V2V automated driving depending on the considered mission and BEV powertrain design.

Abstract Recently, automation of driving has become a significant interest of both industry and academia. Researchers are investigating different facets of automated driving systems (ADS) to address legal, technical, and logistical problems, which will make ADS-equipped vehicles (AVs) a reliable option for daily transportation. One of the most significant challenges that must be addressed before the mass production of AVs is the verification and validation (V&V) of safety and performance. A comprehensive V&V methodology is required to achieve assurance that the AV operates safely even in an uncertain traffic environment. The V&V Task Force under the Society of Automotive Engineers (SAE) On-Road Automated Driving (ORAD) Committee intends to develop such a V&V testing methodology. The first step in this process is a literature review of various AV V&V efforts, which is the purpose of this document.

Abstract In this work, the multicarrier strategies for the three-phase five-level inverter are used on the rotor Field-Oriented Control (FOC) of the Induction Motor (IM). The H-bridge inverter gain uses the triangular carrier technique to produce two Pulse Width Modulation (PWM) command strategies. These two PWM-based strategies, the Phase Disposition Carrier-PWM (PDC-PWM) strategies and the Phase Shifted Carrier-PWM (PSC-PWM) strategies, are compared to find the appropriate command for the designed Electric Vehicle (EV) system. The system is improved by the Fuzzy Logic Control (FLC) to refine its surveillance and to detect any possible deflection in the system. The Automatic Hook (AH) is connected to the front axle of the EV. In case of any divergence, the FLC is programmed to detect the divergence according to the temperature of the semiconductors, the current, the speed, and the trajectory and then it changes the state of the AH to make the needed correction.

Abstract Sensor measurement noise has a great influence on adaptive cruise control (ACC) systems. To improve the robust performance of ACC application in the real world, a Kalman filter-based model predictive control (MPC) method was proposed in this study, in which the Kalman filter was adopted to deal with the measurement noise of state variables, and the MPC controller was developed to improve the ACC system performance of the longitudinal car-following accuracy, safety, and riding comfort. In the proposed MPC controller, a state feedback correction algorithm was applied to improve the accuracy of the predictive model in cases of parameter uncertainty and external disturbances. Then, relaxation factors were introduced to soften and extend the scope of the constraints to obtain a feasible solution.

Abstract This article presents a control strategy to improve the overall energy efficiency of connected and automated-hybrid electric vehicles (CA-HEV) in urban driving conditions. A forward-looking, traffic-aware, high-level decision control (HLDC) algorithm is proposed in this article, where both traffic and road information (obtained from surrounding vehicles and municipal traffic management centers through connected vehicle technologies) are utilized. The objective is to dynamically optimize the vehicle speed trajectories to reduce, and potentially eliminate, idling time at red traffic lights. The benefits include reduced unnecessary engine restart, emissions, and an improvement in the overall energy efficiency of the CA-HEV.

Abstract Adaptive cruise control (ACC) is an advanced driver assistance system (ADAS) that enables vehicle following with desired intervehicular distances. Cooperative adaptive cruise control (CACC) is upgraded ACC that utilizes additional intervehicular wireless communications to share vehicle states such as acceleration to enable shorter gap following. Both ACC and CACC rely on range sensors such as radar to obtain the actual intervehicular distance for gap-keeping control. The range sensor may lose detection of the target, the preceding vehicle, on curvy roads or steep hills due to limited angle of view. Unfavorable weather conditions, target selection failures, or hardware issues may also result in target detection loss. During target detection loss, the vehicle following system usually falls back to cruise control (CC), wherein the ego (following) vehicle maintains a constant speed.

Abstract Hybrid Electric Vehicles (HEVs) are gaining popularity these days mainly due to their high fuel economy. While conventional HEV controllers can be classified into rule-based control and optimization-based control, most of the production vehicles employ rule-based control due to their reliability. However, once the rule is optimized for a given driving pattern, it is not necessarily optimal for other driving patterns. In order to further improve fuel economy for HEVs, this article investigates the feasibility of optimizing control algorithm for different driving patterns so that the vehicle maintains a high level of optimality regardless of the driving patterns.

Abstract Numerous works have been carried out with perspectives to improve the energy efficiency of electric vehicle (EV) drivetrains; much of the attention has been on the design of highly efficient electric motors, power converters, and energy storage system. Besides the abovementioned factors, selection of the drivetrain configuration and control strategy also influence the efficiency and performance of EV drivetrain. The drivetrain efficiency and performance indices, such as torque ripple and total harmonic distortion (THD) of voltage and current, are sensitive to the direct current (dc)-link voltage and flux linkage values for a drivetrain control strategy. Therefore, in this work, the efficiency and the performance of two popular direct torque controlled induction motor (IM) drives are compared on the basis of adjustable dc-link voltage and flux linkage values for desired operating condition. Both these techniques are implemented on a lab scale test bed.

According to the International Civil Aviation Organization, the world aviation air traffic has grown by an average yearly rate of 5% over the last thirty years, until the devastating downturn brought on by the COVID crisis of 2020. Regardless of the current situation, there are still a number of issues and challenges that the industry is confronted with, not the least of which are related to sustainability, the conversion to electrical usage, the challenge of increasing propulsion efficiency in conventional propulsion, the digital transformation of the entire ecosystem, etc. In response, system developers and researchers in the field are working on a number of key technologies and methodologies to solve some of these issues. The Sustainable Aviation Research Society (SARES), a global organization that seeks to encourage research in this area and helps disseminate knowledge via conferences and symposia, has been organizing meetings to promote sustainable aviation over the five years.

Letter from the Special Issue Editors

Abstract For electromechanical actuators (EMAs) and electronic devices cooling on aircraft, there is a need to study cooling fan performance at various altitudes from sea level to 12,000 m where the ambient pressure varies from 1 to 0.2 atm. As fan static pressure head is proportional to air density, the fan’s rotational speed has to be increased significantly to compensate for the low ambient pressure of 0.2 atm at the altitude of 12,000 m. To evaluate fan performance for EMA cooling, a high-rotational-speed, commercially available fan made by Ametek with a diameter of ~82 mm and ~3 m3/min zero-load open cooling flow rate when operating at 20,000 rpm was chosen as the baseline. According to fan scaling laws, this fan was expected to meet the cooling needs for an EMA when operating at 0.2 atm. Using a closed flow loop, the performance of the fan operating in the above ambient pressure range and at a rotational speed between 15,000 and 30,000 rpm was evaluated.