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SAE International Journal of Passenger Cars Mechanical Systems
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Modeling and Performance Analysis of a Field-Aged Fe-Zeolite Catalyst in a Heavy Duty Diesel Engine Application

SAE International Journal of Passenger Cars - Mechanical Systems

Drexel University-Roxanna Moores, Nicholas Cernansky
Volvo Powertrain North America-Gregory Birky, Timothy Suder
  • Journal Article
  • 2016-01-9109
Published 2016-05-18 by SAE International in United States
In this study a 1-dimensional computational model of a Fe-Zeolite catalyst, implementing conservation of mass, species and energy for both gas and catalyst surface phases has been developed to simulate emissions conversion performance. It is applied to both a fresh catalyst and one that has been aged through exposure to the exhaust system of a Heavy Duty Diesel engine performing in the field for 376K miles. Details of the chemical kinetics associated with the various NOx reduction reactions in the two Fe-Zeolite configurations have been examined and correlated with data from a synthetic gas rig test bench. It was found that the Standard reaction, (4NH3 + 4NO + O2 → 2N2 + 6H2O), which is one of the main reactions for NOx reduction, degraded significantly at the lower temperatures for the aged system. Meanwhile the Fast reaction, (4NH3 + 2NO + 2NO2 → 4N2+ 6H2O), was the least affected and as such became the dominant mechanism for obtaining compliant NOx reduction levels towards the end of the product’s rated life.
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Simulation of Atmospheric Turbulence for Wind-Tunnel Tests on Full-Scale Light-Duty Vehicles

SAE International Journal of Passenger Cars - Mechanical Systems

National Research Council Canada-Brian R. McAuliffe, Alanna Wall, Guy Larose
  • Journal Article
  • 2016-01-1583
Published 2016-04-05 by SAE International in United States
During the past year, a novel turbulence generation system has been commissioned in the National Research Council (NRC) 9 m Wind Tunnel. This system, called the Road Turbulence System was developed to simulate with high fidelity the turbulence experienced by a heavy duty vehicle on the road at a geometrical scale of 30%. The turbulence characteristics that it can simulate were defined based on an extensive field measurement campaign on Canadian roads for various conditions (heavy and light traffic, topography, exposure) at heights above ground relevant not only for heavy duty vehicles but also for light duty vehicles.In an effort to improve continually the simulation of the road conditions for aerodynamic evaluations of ground vehicles, a study was carried out at NRC to define the applicability of the Road Turbulence System to aerodynamic testing of full-scale light duty vehicles. Using the on-road measurements as a guide, it was concluded that the RTS appears to provide a more representative simulation of on-road conditions for wind-tunnel testing, compared with other passive methods such as with rope nets,…
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Long-Haul Truck Sleeper Heating Load Reduction Package for Rest Period Idling

SAE International Journal of Passenger Cars - Mechanical Systems

Aearo Technologies LLC-Zhiming Luo, John Zehme
National Renewable Energy Laboratory-Jason Aaron Lustbader, Bidzina Kekelia, Jeff Tomerlin, Cory J. Kreutzer
  • Journal Article
  • 2016-01-0258
Published 2016-04-05 by SAE International in United States
Annual fuel use for sleeper cab truck rest period idling is estimated at 667 million gallons in the United States, or 6.8% of long-haul truck fuel use. Truck idling during a rest period represents zero freight efficiency and is largely done to supply accessory power for climate conditioning of the cab. The National Renewable Energy Laboratory’s CoolCab project aims to reduce heating, ventilating, and air conditioning (HVAC) loads and resulting fuel use from rest period idling by working closely with industry to design efficient long-haul truck thermal management systems while maintaining occupant comfort. Enhancing the thermal performance of cab/sleepers will enable smaller, lighter, and more cost-effective idle reduction solutions. In addition, if the fuel savings provide a one- to three-year payback period, fleet owners will be economically motivated to incorporate them. For candidate idle reduction technologies to be implemented by original equipment manufacturers and fleets, their effectiveness must be quantified. To address this need, several promising candidate technologies were evaluated through experimentation and modeling to determine their effectiveness in reducing rest period HVAC loads. Load…
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High Fidelity Quasi Steady State Aerodynamic Model Development and Effects on Race Vehicle Performance Predictions

SAE International Journal of Passenger Cars - Mechanical Systems

Pratt & Miller Engineering-Jackie A. Mohrfeld-Halterman
UNC Charlotte Motorsports Engineering-Mesbah Uddin
  • Journal Article
  • 2016-01-1589
Published 2016-04-05 by SAE International in United States
Presented in this paper is a procedure to develop a high fidelity quasi steady state aerodynamic model for use in race car vehicle dynamic simulations and its application in a race vehicle multi-body full lap simulation. Developed to fit quasi steady state (QSS) wind tunnel data, the aerodynamic model is regressed against three independent variables: front ground clearance, rear ride height, and yaw angle. An initial dual range model is presented and then further refined to reduce the model complexity while maintaining a high level of predictive accuracy. The model complexity reduction decreases the required amount of wind tunnel data thereby reducing wind tunnel testing time and cost. The quasi steady state aerodynamic model for the pitch moment degree of freedom is systematically developed in this paper. This procedure is extended to the other five aerodynamic degrees of freedom to develop a complete, high fidelity, six degree of freedom quasi steady state aerodynamic model. This high fidelity model reduces the QSS aerodynamic fit error compared to conventional aerodynamic model development. Both the newly developed high…
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Experimental Analysis on the Transitional Mechanism of the Wake Structure of the Ahmed Body

SAE International Journal of Passenger Cars - Mechanical Systems

Suzuki Motor Corp.-Daichi Katoh, Yoshimitsu Hashizume
Tokyo City University-Itsuhei Kohri, Yuji Kobayashi, Akira Kasai, Takayoshi Nasu
  • Journal Article
  • 2016-01-1591
Published 2016-04-05 by SAE International in United States
The critical change in drag occurs in the Ahmed Body at 30° of the slanted base due to the transition in the wake structure. The distinctive feature of this bi-stage phenomenon, which consists of three-dimensional and quasi-axisymmetric separation states, is that the state drastically changes. Because this feature indicates that each state is stable around a critical angle, the transition is believed to be triggered by some instantaneous disturbances. Therefore, in our previous papers, we have paid attention on the unsteady behavior of the wake to determine the trigger that induces the transition. However, the relationship between the spatial transient behavior of the wake structures and the specific frequencies has not been clarified. Then, we tried to control the degree of interaction of the trailing vortices on the downwash by changing the aspect ratio of the slanted base.In the first half, we studied the effects for typical combinations of the slant angle and aspect ratio and conducted an investigation to clarify the relationship between the geometric condition and the transition in the wake structure. In…
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Sideslip Angle Estimation of a Formula SAE Racing Vehicle

SAE International Journal of Passenger Cars - Mechanical Systems

Politecnico di Torino-Jyotishman Ghosh, Andrea Tonoli, Nicola Amati
VI-Grade-Weitao Chen
  • Journal Article
  • 2016-01-1662
Published 2016-04-05 by SAE International in United States
A method for estimating the sideslip angle of a Formula SAE vehicle with torque vectoring is presented. Torque vectoring introduces large tire longitudinal forces which lead to a reduction of the tire lateral forces. A novel tire model is utilized to represent this reduction of the lateral forces. The estimation is realized using an extended Kalman filter which takes in standard sensor measurements. The developed algorithm is tested by simulating slalom and figure eight maneuvers on a validated VI-CarRealTime vehicle model. Results indicate that the algorithm is able to estimate the sideslip angle of the vehicle reliably on a high friction surface track.
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A Fuzzy Inference System for Understeer/Oversteer Detection Towards Model-Free Stability Control

SAE International Journal of Passenger Cars - Mechanical Systems

Clemson Univ.-Beshah Ayalew
Ford Motor Co.-Benjamin Hirche
  • Journal Article
  • 2016-01-1630
Published 2016-04-05 by SAE International in United States
In this paper, a soft computing approach to a model-free vehicle stability control (VSC) algorithm is presented. The objective is to create a fuzzy inference system (FIS) that is robust enough to operate in a multitude of vehicle conditions (load, tire wear, alignment), and road conditions while at the same time providing optimal vehicle stability by detecting and minimizing loss of traction. In this approach, an adaptive neuro-fuzzy inference system (ANFIS) is generated using previously collected data to train and optimize the performance of the fuzzy logic VSC algorithm. This paper outlines the FIS detection algorithm and its benefits over a model-based approach. The performance of the FIS-based VSC is evaluated via a co-simulation of MATLAB/Simulink and CarSim model of the vehicle under various road and load conditions. The results showed that the proposed algorithm is capable of accurately indicating unstable vehicle behavior for two different types of vehicles (SUV and Sedan). The algorithm can do this without any significant parameter adjustment, illustrating its robustness against the considered uncertainty.
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An Experimental Study on Truck Side-Skirt Flow

SAE International Journal of Passenger Cars - Mechanical Systems

University of Cambridge-R.G. Stephens, H. Babinsky
  • Journal Article
  • 2016-01-1593
Published 2016-04-05 by SAE International in United States
The underbody of a truck is responsible for an appreciable portion of the vehicle’s aerodynamic drag, and thus its fuel consumption. This paper investigates experimentally the flow around side-skirts, a common underbody aerodynamic device which is known to be effective at reducing vehicle drag. A full, 1/10 scale European truck model is used. The chassis of the model is designed to represent one that would be found on a typical trailer, and is fully reconfigurable. Testing is carried out in a water towing tank, which allows the correct establishment of the ground flow and rotating wheels. Optical access into the underbody is possible through the clear working section of the facility. Stereoscopic and planar Particle Image Velocimetry (PIV) set-ups are used to provide both qualitative images of and quantitative information on the flow field. The planar PIV set-up employs novel techniques developed in-house, including the use of two laser sheets to reduce shadow regions, and frame averaging such that presented results are produced using an average of up to 1800 independent data points. It is…
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Low-Order Contact Load Distribution Model for Ball Nut Assemblies

SAE International Journal of Passenger Cars - Mechanical Systems

University of Michigan-Bo Lin, Chinedum E. Okwudire
  • Journal Article
  • 2016-01-1560
Published 2016-04-05 by SAE International in United States
Ball nut assemblies (BNAs) are used in a variety of applications, e.g., automotive, aerospace and manufacturing, for converting rotary motion to linear motion (or vice versa). In these application areas, accurate characterization of the dynamics of BNAs using low-order models is very useful for performance simulation and analyses. Existing low-order contact load models of BNAs are inadequate, partly because they only consider the axial deformations of the screw and nut. This paper presents a low-order load distribution model for BNAs which considers the axial, torsional and lateral deformations of the screw and nut. The screw and nut are modeled as finite element beams, while Hertzian Contact Theory is used to model the contact condition between the balls and raceways of the screw and nut. The interactions between the forces and displacements of the screw and nut and those at the ball-raceway contact points are established using transformation matrices. The resulting set of linear and nonlinear equations are solved iteratively using the Newton-Raphson method to obtain the contact load distribution of balls under static equilibrium. A…
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Validation and Application of Digital Simulation for Improving Rear Side Window Buffeting of a Sedan

SAE International Journal of Passenger Cars - Mechanical Systems

SAIC-Volkswagen-Haibo Wu, Jiangbin Zhou, Qian Chen, Gongwen Liu
Shanghai Yirui Automobile Tech.-Chaoqun Qian
  • Journal Article
  • 2016-01-1595
Published 2016-04-05 by SAE International in United States
In this paper we present the work which was done at Shanghai-VW for using computational aero-acoustic (CAA) simulation in the vehicle development process to assess and improve the buffeting behavior of a vehicle when the rear side window is open. In the first step, a methodology was established and validated against wind tunnel tests using a Sedan. The methodology consists of a calibration of the CAA model to represent the properties of the cabin interior of the real car in terms of damping, wall compliance and leakage followed by CAA simulations of the full vehicle at different wind speeds to obtain the transient flow field around the exterior shape and inside the passenger compartment. The interior noise spectra are directly calculated from the transient pressure inside the cabin. For validation, frequency and level of the main buffeting peak at different wind speeds were compared to respective measurements taken in the aero-acoustic wind tunnel of the Shanghai Automotive Wind Tunnel Center. After results with good accuracy were obtained, the simulation methodology was applied to evaluate the…
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