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Journal Article

Evaluation of Dynamic Wheel Alignment Audit System Performance

2019-09-03
Abstract Wheel alignment audit systems are used in vehicle service environments to identify vehicles which may benefit from a comprehensive evaluation on a precision static alignment measurement system. Non-contact dynamic wheel alignment audit systems acquire measurement data from vehicles in motion passing between sensors in an inspection lane. The dynamic nature of the moving vehicles introduces variables which are not present when auditing wheel alignment on a static vehicle. Measurement results are affected by changes in vehicle velocity, steering movement, suspension movement, floor surface conditions, tire sidewall profiles, and driver presence, as well as other variables.
Journal Article

A Guide to Uncertainty Quantification for Experimental Engine Research and Heat Release Analysis

2019-08-22
Abstract Performing an uncertainty analysis for complex measurement tasks, such as those found in engine research, presents unique challenges. Also, because of the excessive computational costs, modeling-based approaches, such as a Monte Carlo approach, may not be practical. This work provides a traditional statistical approach to uncertainty analysis that incorporates the uncertainty tree, which is a graphical tool for complex uncertainty analysis. Approaches to calculate the required sensitivities are discussed, including issues associated with numerical differentiation, numerical integration, and post-processing. Trimming of the uncertainty tree to remove insignificant contributions is discussed. The article concludes with a best practices guide in the Appendix to uncertainty propagation in experimental engine combustion post-processing, which includes suggested post-processing techniques and down-selected functional relationships for uncertainty propagation.
Journal Article

Numerical Study of Pore Size and Distribution Effects on Gasoline Particulate Filter Performance

2019-08-22
Abstract The improved brake thermal efficiency of Gasoline Direct Injection (GDI) engines is accompanied by a significant increase in Particulate Matter (PM) mass and higher Particulate Number (PN) emissions as compared to (multi)Port Fuel Injected (PFI) engines. Gasoline particulate filters (GPFs) with high filtration efficiency and low backpressure will be required to meet the future, stringent PM/PN regulations. A two-dimensional (2D) CFD study was performed to determine the effects of pore size and distribution on the interdependent performance parameters of filtration efficiency and backpressure for clean GPFs. Simulation results show an on linear change infiltration efficiency as the pore size distribution tightens and determine a recommended distribution range, controlling the quantity of small-sized pores. Pore size distributions beyond this recommended range can cause a filtration performance loss or intolerable backpressure penalty for the GPF.
Journal Article

Numerical Aspects Affecting Heat Transfer in ICE Applications and Definition of a Temperature Wall Function Accounting for the Boundary Layer Compressibility

2019-08-22
Abstract The heat transfer phenomena in Internal Combustion Engines (ICEs) are one of the main research topics that need to be addressed to enhance the performance in terms of power, efficiency, emissions and reliability. The present study is focused on the evaluation of the in-cylinder heat fluxes through the use of Computational Fluid Dynamic (CFD) simulations, with a wall function approach. In particular, the aim of this work is to present a new fully non-isothermal wall function obtained from the one-dimensional (1-D) energy balance equation for turbulent flows in the boundary layers, specifying all the steps and assumptions which have carried to the final fully compressible formulation. The new proposed wall function has been validated against experimental data of the General Motors (GM) Pancake Engine, representative of low Brake Mean Effective Pressure (bmep) operating point, comparing the results with other existing wall functions.
Journal Article

Developing a Standardized Performance Evaluation of Vehicles with Automated Driving Features

2019-08-21
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.
Journal Article

Turbulent Flow Pressure Losses in Gasoline Particulate Filters

2019-08-19
Abstract Gasoline Particulate Filter (GPF) technology is the key method of meeting the new regulations for particulate matter emissions from gasoline cars. Computer-Aided Engineering is widely used for the design of such systems; thus the development of accurate models for GPFs is crucial. Most existing pressure loss models require experimental calibration of several parameters. These experiments are performed at room temperatures, or on an engine test bench, where gas properties cannot be fully controlled. This article presents pressure loss measurements for clean GPF cores performed with uniform airflow and temperatures up to 680°C. The flow regime in GPF is shown to be different to that in the Diesel Particulate Filters (DPF) due to high flow rates and temperatures. Therefore, most of the existing models are not suitable for design of the new generation of aftertreatment devices. To separate pressure loss contribution from different sources, unplugged filter cores are tested.
Journal Article

Response Surface Methodology (RSM) in Optimization of Performance and Exhaust Emissions of RON 97, RON 98, and RON 100 (Motor Gasoline) and AVGAS 100LL (Aviation Gasoline) in Lycoming O-320 Engine

2019-08-19
Abstract Federal Aviation Administration (FAA)’s 20 years of research and development with 200 unleaded blends and full-scale engine tests on 45 high-octane unleaded blends has not found a “drop-in” unleaded replacement for aviation gasoline (AVGAS) 100 low lead (100LL) fuel. In this study, analysis of compatibility via optimization of Lycoming O-320 engine fuelled with RON 97, RON 98, RON 100, and AVGAS was conducted using the Response Surface Methodology (RSM). Test fuels were compositionally characterized based on Gas Chromatography (GC) analysis and were categorized based on types of Hydrocarbon (HC). Basic fuel properties of fuels in this research were analyzed and recorded. For optimization analysis, engine speed and fuel were considered as the input parameters.
Journal Article

A New Approach for Development of a High-Performance Intake Manifold for a Single-Cylinder Engine Used in Formula SAE Application

2019-07-26
Abstract The Formula SAE (FSAE) is an international engineering competition where a Formula style race car is designed and built by students from worldwide universities. According to FSAE regulation, an air restrictor with circular cross section of 20 mm for gasoline-fuelled and 19 mm for E-85-fuelled vehicles is to be incorporated between the throttle valve and engine inlet. The sole purpose of this regulation is to limit the airflow to the engine used. The only sequence allowed is throttle valve, restrictor and engine inlet. A new approach of combining ram theory and acoustic theory methods are investigated to increase the performance of the engine by designing an optimized intake runner for a particular engine speed range and an optimized plenum volume in this range. Engine performance characteristics such as brake power, brake torque and volumetric efficiency are taken into considerations.
Journal Article

Motion Cueing Algorithm for a 9-DoF Driving Simulator: MPC with Linearized Actuator Constraints

2019-07-09
Abstract In times when automated driving is becoming increasingly relevant, dynamic simulators present an appropriate simulation environment to faithfully reproduce driving scenarios. A realistic replication of driving dynamics is an important criterion to immerse persons in the virtual environments provided by the simulator. Motion Cueing Algorithms (MCAs) compute the simulator’s control input, based on the motions of the simulated vehicle. The technical restrictions of the simulator’s actuators form the main limitation in the execution of these input commands. Typical dynamic simulators consist of a hexapod with six degrees of freedom (DoF) to reproduce the vehicle motion in all dimensions. Since its workspace dimensions are limited, significant improvements in motion capabilities can be achieved by expanding the simulator with redundant DoF by means of additional actuators.
Journal Article

Speed Planning and Prompting System for Commercial Vehicle Based on Real-Time Calculation of Resistance

2019-06-25
Abstract When commercial vehicles drive in a mountainous area, the complex road condition and long slopes cause frequent acceleration and braking, which will use 25% more fuel. And the brake temperature rises rapidly due to continuous braking on the long-distance downslopes, which will make the brake drum fail with the brake temperature exceeding 308°C [1]. Meanwhile, the kinetic energy is wasted during the driving progress on the slopes when the vehicle rolls up and down. Our laboratory built a model that could calculate the distance from the top of the slope, where the driver could release the accelerator pedal. Thus, on the slope, the vehicle uses less fuel when it rolls up and less brakes when down. What we do in this article is use this model in a real vehicle and measure how well it works.
Journal Article

Optimizing Cooling Fan Power Consumption for Improving Diesel Engine Fuel Efficiency Using CFD Technique

2019-06-11
Abstract Fan cooling system of an air-cooled diesel engine is optimized using 3D CFD numerical simulation approach. The main objective of this article is to increase engine fuel efficiency by reducing fan power consumption. It is achieved by optimizing airflow rates and flow distribution over the engine surfaces to keep the maximum temperature of engine oil and engine surfaces well within the lubrication and material limit, respectively, at the expense of lower fan power. Based on basic fan laws, a bigger fan consumes lesser power for the same airflow rate as compared to a smaller fan, provided both fans have similar efficiency. Flow analysis is also conducted with the engine head and block modeled as solid medium and fan cooling system as fluid domain. Reynolds-averaged Navier-Stokes turbulence (RANS) equations were solved to get the flow field inside the cooling system and on the engine liner fins. The Moving Reference Frame approach was used for simulating the rotation of a fan.
Journal Article

Design and Experiment on Aircraft Electromechanical Actuator Fan at Different Altitudes and Rotational Speeds

2019-06-07
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.
Journal Article

Process Regulations and Mechanism of WEDM of Combustor Material

2019-06-07
Abstract This study discusses the experimental investigation on WEDM of combustor material (i.e., nimonic 263). Experimentation has been executed by varying pulse-on time (Ton), pulse-off time (Toff), peak current (Ip), and spark gap voltage (Sv). Material removal rate (MRR), surface roughness (SR), and wire wear rate (WWR) are employed as process performance characteristics. Experiments are designed as per the box-Behnken design technique. Parametric optimization has also been performed using response surface methodology. Besides this, field-emission scanning electron microscope (FE-SEM) and an optical microscope are utilized to characterize WEDMed and worn-out wire surfaces. It is observed that both surfaces contain micro-cracks, craters, spherical droplets, and a lump of debris. Furthermore, the mechanism of recast layer formation has been critically evaluated to apprehend a better understanding of the technique. The key features of the experimental procedure are also highlighted.
Journal Article

A Review on Electromagnetic Sheet Metal Forming of Continuum Sheet Metals

2019-05-29
Abstract Electromagnetic forming (EMF) is a high-speed impulse forming process developed during the 1950s and 1960s to acquire shapes from sheet metal that could not be obtained using conventional forming techniques. In order to attain required deformation, EMF process applies high Lorentz force for a very short duration of time. Due to the ability to form aluminum and other low-formability materials, the use of EMF of sheet metal for automobile parts has been rising in recent years. This review gives an inclusive survey of historical progress in EMF of continuum sheet metals. Also, the EMF is reviewed based on analytical approach, finite element method (FEM) simulation-based approach and experimental approach, on formability of the metals.
Journal Article

Mixture Distributions in Autonomous Decision-Making for Industry 4.0

2019-05-29
Abstract Industry 4.0 is expected to revolutionize product development and, in particular, manufacturing systems. Cyber-physical production systems and digital twins of the product and process already provide the means to predict possible future states of the final product given the current production parameters. With the advent of further data integration coupled with the need for autonomous decision-making, methods are needed to make decisions in real time and in an environment of uncertainty in both the possible outcomes and in the stakeholders’ preferences over them. This article proposes a method of autonomous decision-making in data-intensive environments, such as a cyber-physical assembly system. Theoretical results in group decision-making and utility maximization using mixture distributions are presented. This allows us to perform calculations on expected utility accurately and efficiently through closed-form expressions, which are also provided.
Journal Article

Development of a Standard Testing Method for Vehicle Cabin Air Quality Index

2019-05-20
Abstract Vehicle cabin air quality depends on various parameters such as number of passengers, fan speed, and vehicle speed. In addition to controlling the temperature inside the vehicle, HVAC control system has evolved to improve cabin air quality as well. However, there is no standard test method to ensure reliable and repeatable comparison among different cars. The current study defined Cabin Air Quality Index (CAQI) and proposed a test method to determine CAQI. CAQIparticles showed dependence on the choice of metrics among particle number (PN), particle surface area (PS), and particle mass (PM). CAQIparticles is less than 1 while CAQICO2 is larger than 1. The proposed test method is promising but needs further improvement for smaller coefficient of variations (COVs).
Journal Article

Experimental Analysis of SCR Spray Evolution and Sizing in High-Temperature and Flash Boiling Conditions

2019-05-16
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.
Journal Article

Cooperative Ramp Merging System: Agent-Based Modeling and Simulation Using Game Engine

2019-05-16
Abstract Agent-based modeling and simulation (ABMS) has been a popular approach for modeling autonomous and interacting agents in a multi-agent system. Specifically, ABMS can be applied to connected and automated vehicles (CAVs) since CAVs can operate autonomously with the help of onboard sensors, and cooperate with each other through vehicle-to-everything (V2X) communications. In order to improve energy efficiency and mobility of traffic, we have developed an online feedforward/feedback longitudinal controller for CAVs to cooperatively merge at ramps. Agent-based CAV models were built in the Unity3D environment, where vehicles are given connectivity and autonomy through C#-based scripting API. Agent-based infrastructure model is also built as a Unity3D simulation network based on the city of Mountain View, California.
Journal Article

A Review on Physical Mechanisms of Tire-Pavement Interaction Noise

2019-05-16
Abstract Tire-pavement interaction noise (TPIN) dominates for passenger cars above 40 km/h and trucks above 70 km/h. Numerous studies have attempted to uncover and distinguish the basic mechanisms of TPIN. However, intense debate is still ongoing about the validity of these mechanisms. In this work, the physical mechanisms proposed in the literature were reviewed and divided into three categories: generation mechanisms, amplification mechanisms, and attenuation mechanisms. The purpose of this article is to gather the published general opinions for further open discussions.
Journal Article

Comparative Study of Different Air Supply Systems for Automotive Fuel Cell Applications

2019-05-10
Abstract The dynamic and efficiency of automotive fuel cell drives is significantly influenced by air supply system. Different air compression architectures use electric compressor (EC), electric turbocharger (ETC), or a serial booster (SB) consisting of turbocharger and electric compressor. These three variants of air compression systems were modeled using a map approach and added to a 0D fuel cell air supply model. The characteristic maps of the turbomachinery were measured on the test bench under fuel cell conditions. Subsequently, the calculated isentropic efficiencies were corrected with respect to heat transfer phenomena occurring during the measurement. Moreover, a scaling method for the maps of the turbomachinery is explained. The initial simulation of the air compression systems with equal diameters for the turbomachinery showed no difference in the mechanical power demand.
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