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SAE International Journal of Passenger Cars Mechanical Systems
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Distinction of Roller Bearing Defect from Gear Defect via Envelope Process and Autocorrelation Enhancement

SAE International Journal of Passenger Cars - Mechanical Systems

Czech Technical University in Prague-Gabriela Achtenova
Helwan University, Egypt-Mohamed El Morsy
  • Journal Article
  • 2017-01-9681
Published 2017-05-18 by SAE International in United States
Bearing and gear condition monitoring are important to improve a mechanical system reliability and performance. In the early stage of bearing failures, the Bearing Characteristic Frequencies (BCFs) contain very little energy and are often overwhelmed by noise and higher-level macro-structural vibrations, an effective signal processing method would be necessary to eliminate such corrupting noise and interference. Referring to the non-stationary characteristics of roller bearing fault vibration signals, a roller bearing condition monitoring method based on Envelope Process to raw time-domain vibration signal and Autocorrelation enhancement to the residual signal is put forward in this paper. The concept of Envelope and Autocorrelation techniques and its implementation for defect identification are discussed. Also, distinction of bearing fault signal as cyclostationary from periodic signal for gear fault. An automotive gearbox is used on the test stand, which is equipped with three dynamometers; the input dynamometer serves as internal combustion engine, the output dynamometers introduce the load on the flanges of output joint shafts. This assertion is demonstrated by introducing an experimental study on artificial defects in one roller…
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An Experimental Study of Sloshing Noise in a Partially Filled Rectangular Tank

SAE International Journal of Passenger Cars - Mechanical Systems

Indian Institute of Technology Hyderabad-G Agawane, Varun Jadon, Venkatesham Balide, R Banerjee
  • Journal Article
  • 2017-01-9678
Published 2017-05-18 by SAE International in United States
Liquid sloshing noise from an automotive fuel tank is becoming increasingly important during frequent accelerating/decelerating driving conditions. It is becoming more apparent due to significant decrease in other noise sources in a vehicle, particularly in hybrid vehicles. As a step toward understanding the dynamics of liquid sloshing and noise generation mechanism, an experimental study was performed in a partially filled rectangular tank. A systematic study was performed to understand the effects of critical parameters like fill level and acceleration/deceleration magnitude. Response parameters like dynamic pressure, dynamic force, dynamic acceleration and sound pressure levels along with high speed video images were recorded. The proposed experimental setup was able to demonstrate major events leading to sloshing noise generation. These events in the sloshing mechanism have been analysed from the dynamic sensor data and correlated with high speed video images.
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On the Effects of Wind Tunnel Floor Tangential Blowing on the Aerodynamic Forces of Passenger Vehicles

SAE International Journal of Passenger Cars - Mechanical Systems

Chalmers University of Technology-Emil Ljungskog, Simone Sebben
Volvo Cars-Alexander Broniewicz, Christoffer Landström
  • Journal Article
  • 2017-01-1518
Published 2017-03-28 by SAE International in United States
Many aerodynamic wind tunnels used for testing of ground vehicles have advanced ground simulation systems to account for the relative motion between the ground and the vehicle. One commonly used approach for ground simulation is a five belt system, where moving belts are used, often in conjunction with distributed suction and tangential blowing that reduces the displacement thickness of the boundary layer along the wind tunnel floor. This paper investigates the effects from aft-belt tangential blowing in the Volvo Cars Aerodynamic wind tunnel. First the uniformity of the boundary layer thickness downstream of the blowing slots is examined in the empty tunnel. This is followed by investigations of how the measured performance of different vehicle types in several configurations, typically tested in routine aerodynamic development work, depends on whether the tangential blowing system is active or not. Numerical simulations are also used to explain the flow field origin of the force differences measured in the wind tunnel. Results show that even though the displacement thickness behind the blowers varies along the width of the blowing…
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Prediction Method for Water Intrusion into the Engine Air Intake Duct while Running on Flooded Road at the Early Stage of Vehicle Development

SAE International Journal of Passenger Cars - Mechanical Systems

Honda R&D Co., Ltd.-Kunihiko Yoshitake, Hiroyuki Tateyama, Atsushi Ogawa
  • Journal Article
  • 2017-01-1322
Published 2017-03-28 by SAE International in United States
Vehicles are required durability in various environments all over the world. Especially water resistance on flooded roads is one of the important issues. To solve this kind of problem, a CFD technology was established in order to predict the water resistance performance of the vehicle at the early development stage. By comparison with vehicle tests on flooded roads, it is clarified the following key factors are required for accurate prediction; the vehicle velocity change, the vehicle height change and the air intake flow rate. Moreover, these three key factors should be appropriately determined from vehicle and engine specification to predict water intrusion for flooded roads at the early stage of development. In this paper, a methodology which determines appropriate analysis conditions mentioned above for flooding simulation from vehicle and engine specification is described. The methodology enables us to determine whether the vehicle provides sufficient waterproofness. Further, it is confirmed that the CFD with the methodology can successfully reproduce critical phenomena for water intrusion into the air intake duct.
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Predicted Machining Dynamics for Powertrain Machining

SAE International Journal of Passenger Cars - Mechanical Systems

Ford Motor Company-Youssef Ziada, Juhchin Yang, David DeGroat-Ives
  • Journal Article
  • 2017-01-1330
Published 2017-03-28 by SAE International in United States
Owing to decreased development cycle timing, designing components for manufacturability has never been as important. Assessing manufacturing feasibility has therefore become an increasingly important part of new product engineering. This manufacturing feasibility is conventionally assessed based on static stiffness of components and fixture assemblies. However, in many operations, excess vibration represents the actual limitation on processing a workpiece. Limits on how far into components a tool can reach or the amount of processing time required to machine a feature is commonly decreased significantly due to vibration. Critical time is spent resolving these vibration problems during product launches. Depending on the machining configurations these vibrations can be due to the part & work support structure or due to the tooling & spindle assembly. This paper presents approaches for predicting the dynamic flexibility for either of these assemblies using purely analytical approaches. Results from experiential modal testing are subsequently used to validate the approaches shown. Also by predicting the frequency content of the cutting forces, the risk of resonance or harmonic resonance during machining can also be…
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Development of Prediction Method for Engine Compartment Water Level by Using Coupled Multibody and Fluid Dynamics

SAE International Journal of Passenger Cars - Mechanical Systems

Toyota Motor Corporation-Yoshiteru Tanaka, Jun Yamamura, Atsushi Murakawa, Hiroshi Tanaka, Tsuyoshi Yasuki
  • Journal Article
  • 2017-01-1328
Published 2017-03-28 by SAE International in United States
When vehicles run on the flooded road, water enters to the engine compartment and sometimes reaches the position of the air intake duct and electrical parts and causes the reliability problems. Numerical simulation is an effective tool for this phenomenon because it can not only evaluate the water level before experiment but also identify the intrusion route. Recently, the gap around the engine cooling modules tends to become smaller and the undercover tends to become bigger than before in order to enhance the vehicle performance (e.g., aerodynamics, exterior noise). Leakage tightness around the engine compartment becomes higher and causes an increase of the buoyancy force from the water. Therefore the vehicle attitude change is causing a greater impact on the water level. This paper describes the development of a water level prediction method in engine compartment while running on the flooded road by using the coupled multibody and fluid dynamics. MPS (Moving Particle Semi-implicit) method was used to analyze the free surface flow and 3-dimensional multibody dynamics analysis was applied to calculate the suspension displacement…
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Optimization of Active Grille Shutters Operation for Improved Fuel Economy

SAE International Journal of Passenger Cars - Mechanical Systems

Exa Corp.-Young-Chang Cho, Chin-Wei Chang, Andrea Shestopalov, Edward Tate
  • Journal Article
  • 2017-01-1513
Published 2017-03-28 by SAE International in United States
The airflow into the engine bay of a passenger car is used for cooling down essential components of the vehicle, such as powertrain, air-conditioning compressor, intake charge air, batteries, and brake systems, before it returns back to the external flow. When the intake ram pressure becomes high enough to supply surplus cooling air flow, this flow can be actively regulated by using arrays of grille shutters, namely active grille shutters (AGS), in order to reduce the drag penalty due to excessive cooling. In this study, the operation of AGS for a generic SUV-type model vehicle is optimized for improved fuel economy on a highway drive cycle (part of SFTP-US06) by using surrogate models. Both vehicle aerodynamic power consumption and under-hood cooling performance are assessed by using PowerFLOW, a high-fidelity flow solver that is fully coupled with powertrain heat exchanger models. The fuel economy calculation is based on a quasi-static drive cycle simulation where the engine power is calculated to match drive cycle loads from aerodynamic forces, translational and rotational inertia, rolling resistance, transmission and tire…
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Further Analyses on Prediction of Automotive Spinning Wheel Flowfield with Full Width Moving Belt Wind Tunnel Results

SAE International Journal of Passenger Cars - Mechanical Systems

Exa Corporation-Young-Chang Cho
FCA US LLC-Arturo Guzman, John Tripp, Kumar Srinivasan
  • Journal Article
  • 2017-01-1519
Published 2017-03-28 by SAE International in United States
Pickup trucks are designed with a taller ride height and a larger tire envelope compared to other vehicle types given the duty cycle and environment they operate in. These differences play an important role in the flow field around spinning wheels and tires and their interactions with the vehicle body. From an aerodynamics perspective, understanding and managing this flow field are critical for drag reduction, wheel design, and brake cooling. Furthermore, the validation of numerical simulation methodology is essential for a systematic approach to aerodynamically efficient wheel design as a standard practice of vehicle design.This paper presents a correlation the near-wheel flow field for both front and rear spinning wheels with two different wheel designs for a Ram Quad Cab pick-up truck with moving ground.Twelve-hole probe experimental data obtained in a wind tunnel with a full width belt system are compared to the predictions of numerical simulations. In addition to the previous study on a minivan, this paper provides more detailed correlations for a set of new data with two different rim configurations and multiple…
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Effects of Installation Environment on Flow around Rear View Mirror

SAE International Journal of Passenger Cars - Mechanical Systems

Tongji University-Haidong Yuan, Zhigang Yang, Qiliang Li
  • Journal Article
  • 2017-01-1517
Published 2017-03-28 by SAE International in United States
External rear view mirror is attached at the side of the vehicle which is to permit clear vision for the driver to the rear of the vehicle. When the vehicle is running, the flow field around external rear view mirror is highly three-dimensional, unsteady, separated and turbulent which is known to be a significant source of aerodynamic noise and a contributor to the total drag force on the vehicle. While among all the researches on the flow field around external rear view mirror, different installation environment were employed. The external rear view mirror is mounted on a production car in most researches which presents the real condition and it can also be mounted on the ground of a wind tunnel, a specially designed table, or a generic vehicle model based on the SAE model. While, the relationship between the flow field around external rear view mirror and the installation environment is not very clear.A new open-source realistic car model which is called the DrivAer model is used as the baseline case. The external rear view…
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Aerodynamic Investigation of Cooling Drag of a Production Sedan Part 1: Test Results

SAE International Journal of Passenger Cars - Mechanical Systems

Ford Motor Company-Levon Larson, Sudesh Woodiga, Ronald Gin, Robert Lietz
  • Journal Article
  • 2017-01-1521
Published 2017-03-28 by SAE International in United States
The airflow that enters the front grille of a ground vehicle for the purpose of component cooling has a significant effect on aerodynamic drag (engine airflow drag). Furthermore, engine airflow is known to be capable of influencing upstream external airflow (interference drag). The combined effect of these phenomena is commonly referred to as cooling drag, which generally contributes up to 10% of total vehicle drag. Due to this coupled nature, cooling drag is difficult to understand as it contains influences from multiple locations around the vehicle. A good understanding of the sources of cooling drag is paramount to drive vehicle design to a low cooling drag configuration. In this work, a production level Lincoln MKZ was modified so that a number of variables could be tested in both static ground and moving ground wind tunnel conditions. All tests were conducted at 80 MPH. The variables studied were: underbody shield coverage, heat exchanger resistance, cooling pack configuration, vehicle attitude, front-end sealing, exit path sealing, engine bay blockage and active grille shutter (AGS) configuration. In addition to…
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