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Journal Article

Role of Piston Bowl Shape to Enhance Late-Cycle Soot Oxidation in Low-Swirl Diesel Combustion

2019-04-25
Abstract Late-cycle soot oxidation in heavy-duty (HD) diesel engine low-swirl combustion was investigated using single-cylinder engine and spray chamber experiments together with engine combustion simulations. The in-cylinder flow during interactions between adjacent flames (flame-flame events) was shown to have a large impact on late-cycle combustion. To modify the flame-flame flow, a new piston bowl shape with a protrusion (wave) was designed to guide the near-wall flow. This design significantly reduced soot emissions and increased engine thermodynamic efficiency. The wave’s main effect was to enhance late-cycle mixing, as demonstrated by an increase in the apparent rate of heat release after the termination of fuel injection. Combustion simulations showed that the increased mixing is driven by enhanced flow re-circulation, which produces a radial mixing zone (RMZ).
Journal Article

CAN-Bus Remote Monitoring: Standalone CAN Sensor Reading and Automotive Diagnostics

2019-02-08
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.
Journal Article

Uncertainty Analysis of High-Frequency Noise in Battery Electric Vehicle Based on Interval Model

2019-02-01
Abstract The high-frequency noise issue is one of the most significant noise, vibration, and harshness problems, particularly in battery electric vehicles (BEVs). The sound package treatment is one of the most important approaches toward solving this problem. Owing to the limitations imposed by manufacturing error, assembly error, and the operating conditions, there is often a big difference between the actual values and the design values of the sound package components. Therefore, the sound package parameters include greater uncertainties. In this article, an uncertainty analysis method for BEV interior noise was developed based on an interval model to investigate the effect of sound package uncertainty on the interior noise of a BEV. An interval perturbation method was formulated to compute the uncertainty of the BEV’s interior noise.
Journal Article

Experimental Study of Ignition Delay, Combustion, and NO Emission Characteristics of Hydrogenated Vegetable Oil

2019-02-01
Abstract In this article, a comparative study of hydrogenated vegetable oil (HVO) and Diesel was performed in two constant volume combustion rigs and an optical accessible compression-ignited chamber (OACIC). Ignition, combustion, and nitric oxide (NO) emissions were studied under constant ambient gas density of 16.4 kg/m3, 21% vol oxygen concentration, and two different injection pressures of 800 and 1000 bar. Emission of NO was measured only in the OACIC, while a line-of-sight soot temperature distribution by applying two-color pyrometry was investigated in both setups. In general, the HVO as alternative fuel showed shorter ignition delay and less NO emission than Diesel for both injection pressures. Due to difference in the molecular structure, soot temperature of biofuel flames had narrower temperature spectrum than conventional fuel. Moreover, this study reveals the significance of wall-jet interaction for utilization of the biofuel.
Journal Article

Study of Temperature Distribution and Parametric Optimization during FSW of AA6082 Using Statistical Approaches

2019-02-01
Abstract In this article, Al-Mg-Si-Mn alloy (AA6082) is butt joined by employing friction stir welding (FSW). The mechanical and metallurgical properties of joints are analyzed by conducting tensile and microhardness testing, respectively. To measure the temperature at different locations, eight thermocouples (L-shaped k-type) are placed at equal distance from the centerline. Least square method attempts to calculate the temperature at the centerline of joints. The process parameters are also optimized using Taguchi’s five-level experimental design. The optimum process parameters are determined, employing ultimate tensile strength (UTS) as a response parameter. A statistical test “analysis of variance” is used to check the adequacy of the model. It has been observed that rotational speed and feed rate are the predominant factors for UTS and microhardness.
Journal Article

A Study of Low Temperature Plasma-Assisted Gasoline HCCI Combustion

2019-01-29
Abstract In this study low temperature plasma technology was applied to expand auto-ignition operation region and control auto-ignition phasing of the homogeneous charge compression ignition (HCCI) combustion. The low temperature plasma igniter of a barrier discharge model (barrier discharge igniter (BDI)) with high-frequency voltage (15 kHz) was provided at the top center of the combustion chamber, and the auto-ignition characteristics of the HCCI combustion by the low temperature plasma assistance was investigated by using a single-cylinder gasoline engine. HCCI combustion with compression ratio of 15:1 was achieved by increasing the intake air temperature. The lean air-fuel (A/F) ratio limit and visualized auto-ignition combustion process on baseline HCCI without discharge assistance, spark-assisted HCCI, and BDI-assisted HCCI were compared.
Journal Article

Electrifying Long-Haul Freight-Part II: Assessment of the Battery Capacity

2019-01-25
Abstract Recently, electric heavy-duty tractor-trailers (EHDTTs) have assumed significance as they present an immediate solution to decarbonize the transportation sector. Hence, to illustrate the economic viability of electrifying the freight industry, a detailed numerical model to estimate the battery capacity for an EHDTT is proposed for a route between Washington, DC, to Knoxville, TN. This model incorporates the effects of the terrain, climate, vehicular forces, auxiliary loads, and payload in order to select the appropriate motor and optimize the battery capacity. Additionally, current and near-future battery chemistries are simulated in the model. Along with equations describing vehicular forces based on Newton’s second law of motion, the model utilizes the Hausmann and Depcik correlation to estimate the losses caused by the capacity offset of the batteries. Here, a Newton-Raphson iterative scheme determines the minimum battery capacity for the required state of charge.
Journal Article

Separable and Standard Monte Carlo Simulation of Linear Dynamic Systems Using Combined Approximations

2019-01-25
Abstract Reliability analysis of a large-scale system under random dynamic loads can be a very time-consuming task since it requires repeated studies of the system. In many engineering problems, for example, wave loads on an offshore platform, the excitation loads are defined using a power spectral density (PSD) function. For a given PSD function, one needs to generate many time histories to make sure the excitation load is modeled accurately. Global and local approximation methods are available to predict the system response efficiently. Each way has their advantages and shortcomings. The combined approximations (CA) method is an efficient method, which combines the advantages of local and global approximations. This work demonstrates two methodologies that utilize CA to reduce the cost of crude or separable Monte Carlo simulation (MCS) of linear dynamic systems when the excitation loads are defined using PSD functions.
Journal Article

Hewing Out Evacuation Routes for Burning Buses by Linear-Shaped Charge Jet

2019-01-25
Abstract In recent years, several buses have ignited in some cities in China, causing numerous deaths and significant property damage. However, few research studies have been conducted to deal with such accidents. Therefore, in this work, a linear-shaped charge jet with rectangular cross sections was used to hew out evacuation routes for burning buses, and the parameter design for the shaped charge jet was improved according to asymmetry limitations and human tolerance. A numerical finite element simulation model of the behavior of a jet penetrating the jambs was established using ANSYS/LS-DYNA software. The asymmetrical characteristics of an arc segment in the structure of a rectangular-shaped charge were analyzed, in addition to the influence on the deviations of the jet penetration capacity and blast injuries to occupants caused by the side effects of detonation.
Journal Article

Development of a New Neutral Coasting Control Utilizing ADAS and GPS

2019-01-23
Abstract It has been discussed in numerous prior studies that in-neutral coasting, or sailing, can accomplish considerable amount of fuel saving when properly used. The driving maneuver basically makes the vehicle sail in neutral gear when propulsion is unnecessary. By disengaging a clutch or shifting the gear to neutral, the vehicle may better utilize its kinetic energy by avoiding dragging from the engine side. This strategy has been carried over to series production recently in some of the vehicles on the market and has become one of the eco-mode features available in current vehicles. However, the duration of coasting must be long enough to attain more fuel economy benefit than deceleration fuel cutoff (DFCO)-which exists in all current vehicle powertrain controllers-can bring. Also, the transients during shifting back to drive gear can result in a drivability concern.
Journal Article

Design and Development of a Semi-Autonomous Trailer Concept

2019-01-23
Abstract This work builds on previous efforts to develop a self-propelled, semi-autonomous trailer, for use with a standard passenger car. This trailer design involves a power source on the trailer itself, as well as the capacity to sense the load present in the trailer hitch that joins it to the towing vehicle. The load-sensing trailer hitch is used as the input to a control algorithm to determine how much power is required from the trailer’s power source. Two similar concepts were designed and constructed, using different approaches and different scales for testing. Preliminary testing was carried out, and while work remains to be done in order to produce a production-ready design, the progress made further demonstrates the feasibility and value of such a design. Future work will carry forward the research and development of this concept, with the goal of determining the best scheme for practical implementation.
Journal Article

The Key Role of Advanced, Flexible Fuel Injection Systems to Match the Future CO2 Targets in an Ultra-Light Mid-Size Diesel Engine

2019-01-23
Abstract The article describes the results achieved in developing a new diesel combustion system for passenger car application that, while capable of high power density, delivers excellent fuel economy through a combination of mechanical and thermodynamic efficiencies improvement. The project stemmed from the idea that, by leveraging the high fuel injection pressure of last generation common rail systems, it is possible to reduce the engine peak firing pressure (pfp) with great benefits on reciprocating and rotating components’ light-weighting and friction for high-speed light-duty engines, while keeping the power density at competitive levels. To this aim, an advanced injection system concept capable of injection pressure greater than 2500 bar was coupled to a prototype engine featuring newly developed combustion system. Then, the matching among these features has been thoroughly experimentally examined.
Journal Article

Analysis of Temperature Swing Thermal Insulation for Performance Improvement of Diesel Engines

2019-01-23
Abstract Insulating combustion chamber surfaces with thermal barrier coatings (TBCs) provides thermal efficiency improvement when done appropriately. This article reports on insulation heat transfer, engine performance characteristics, and damage modelling of “temperature swing” TBCs. “Temperature swing” insulation refers to the insulation material applied on surfaces of combustion chamber walls that enables selective manipulation of its surface temperature profile over the four strokes of an engine cycle. A combined GT Suite-ANSYS Fluent simulation methodology is developed to investigate the impact of thermal properties and insulation thickness for a variety of TBC materials for its “temperature swing” characteristics. This one-dimensional transient heat conduction analyses and engine cycle simulations are performed using scaled-down thermal properties of yttria-stabilized zirconia.
Journal Article

Low Cycle Fatigue and Ratcheting Behavior of SA333 Gr-6 Steel at 300°C Temperature

2019-01-23
Abstract The objective of this investigation is to study the cyclic deformation behavior of SA333 Gr-6 C-Mn steel at 300°C. Low cycle fatigue tests were carried out at total strain amplitude between ±0.35 and ±1.25% at a constant strain rate of 1 × 10−3 s−1. Ratcheting tests were conducted at a various combination of mean stress and stress amplitude at a constant stress rate of 115 MPa s−1. The material SA333 Gr-6 steel exhibits cyclic hardening throughout its fatigue life. The material shows non-Masing behavior and deviation (δσo ) from Masing behavior increase with an increase of strain amplitude. Ratcheting strain accumulation increases, whereas ratcheting life decreases with an increase in mean stress or stress amplitude. With an increase in mean stress and stress amplitude, ratcheting rate also increases. The material shows hardening characteristic due to dynamic strain aging (DSA) phenomena.
Journal Article

A Comprehensive Attack and Defense Model for the Automotive Domain

2019-01-17
Abstract In the automotive domain, the overall complexity of technical components has increased enormously. Formerly isolated, purely mechanical cars are now a multitude of cyber-physical systems that are continuously interacting with other IT systems, for example, with the smartphone of their driver or the backend servers of the car manufacturer. This has huge security implications as demonstrated by several recent research papers that document attacks endangering the safety of the car. However, there is, to the best of our knowledge, no holistic overview or structured description of the complex automotive domain. Without such a big picture, distinct security research remains isolated and is lacking interconnections between the different subsystems. Hence, it is difficult to draw conclusions about the overall security of a car or to identify aspects that have not been sufficiently covered by security analyses.
Journal Article

An Approach for Heavy-Duty Vehicle-Level Engine Brake Performance Evaluation

2019-01-08
Abstract An innovative analysis approach to evaluate heavy-duty vehicle downhill engine brake performance was developed. The vehicle model developed with GT-Drive simulates vehicle downhill control speeds with different engine brake retarding powers, transmission gears, and vehicle weights at sea level or high altitude. The outputs are then used to construct multi-factor parametric design charts. The charts can be used to analyze the vehicle-level engine brake capabilities or compare braking performance difference between different engine brake configurations to quantify the risk of engine retarding power deficiency at both sea level and high altitude downhill driving conditions.
Journal Article

Development, Testing, and Assessment of a Kinematic Path-Following Model for Towing Vehicle Systems

2019-01-07
Abstract A kinematic path-following model is developed based on an existing modeling framework established by the authors [1, 2] for prediction of the paths of towing vehicle systems. The presented path-following model determines the path of the towing vehicle using the vehicle’s speed and acceleration data collected by an inertial measurement unit (IMU). An Ackerman steering model was presented to calculate instantaneous directional angles and radii for each towed vehicle based on its geometric data and steering angle. In that model the off-tracking effect is properly captured. A 1:4 scale model for a towing vehicle system was built to test the developed steering model, and it was found that the angles and radii of the towing vehicle and each towed unit calculated using the Ackerman steering model agreed very well with those measured from the scale model.
Journal Article

Assessing Road Load Coefficients of a Semi-Trailer Combination Using a Mechanical Simulation Software with Calibration Corrections

2019-01-07
Abstract The study of road loads on trucks plays a major role in assessing the effect of heavy-vehicle design on fuel conservation measures. Coastdown testing with full-scale vehicles in the field offers a good avenue to extract drag components, provided that random instrumentation faults and biased environmental conditions do not introduce errors into the results. However, full-scale coastdown testing is expensive, and environmental biases which are ever-present are difficult to control in the results reduction. Procedures introduced to overcome the shortcomings of full-scale field testing, such as wind tunnels and computational fluid dynamics (CFD), though very reliable, mainly focus on estimating the effects of aerodynamic drag forces to the neglect of other road loads which should be considered.
Journal Article

Onboard Natural Gas Reforming for Heavy Duty Vehicles

2019-01-07
Abstract Powertrain simulations and catalyst studies showed the efficiency credits and feasibility of onboard reforming as a way to recover waste heat from heavy duty vehicles (HDVs) fueled by natural gas (NG). Onboard reforming involves 1) injecting NG into the exhaust gas recycle (EGR) loop of the HDV, 2) reforming NG on a catalyst in the EGR loop to hydrogen and carbon monoxide, and 3) combusting the reformed fuel in the engine. The reformed fuel has increased heating value (4-10% higher LHV) and flame speed over NG, allowing stable flames in spark ignition (SI) engines at EGR levels up to 25-30%. A sulfur-tolerant reforming catalyst was shown to reform a significant amount of NG (15-30% conversion) using amounts of precious metal near the current practice for HDV emissions control (10 g rhodium). Engine simulations showed that the high EGR levels enabled by onboard reforming are used most effectively to control engine load instead of waste-gating or throttling.
Journal Article

Artificial Lightning Tests on Metal and CFRP Automotive Bodies: A Comparative Study

2019-01-07
Abstract Carbon fiber reinforced plastic (CFRP) has been used in automobiles as well as airplanes. Because of its light weight and high strength, CFRP is a good choice for making vehicle bodies lighter, which would improve fuel economy. Conventional metal bodies provide a convenient body return for electric wiring and offer good shielding against electromagnetic fields. Although CFRP is a conductor, its conductivity is much lower than that of metals. Therefore, CFRP bodies are usually not useful for electric wiring. In thunderstorms, an automotive body is considered to be a Faraday cage that protects the vehicle’s occupants from the potential harms of lightning. Before CFRP becomes widely applied to automotive bodies, its electric and electromagnetic properties need to be investigated in order to determine whether it also works as a Faraday cage against lightning. In this article, CFRP and metal body vehicles were tested under artificial lightning.
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