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Development of an Accelerated Test for Tire Flat-Spotting

NissanTechnical Center North America-Farokh Kavarana, Scott Fritz
Published 2019-06-05 by SAE International in United States
Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time, and can be temporary or permanent depending on the length of storage, vehicle loading and environmental factors. Tire non-uniformity caused from flat-spots often induce shake and shimmy vibration in vehicles due to increased tire-wheel force variation input into the chassis. This results in increased warranty costs for OEMs and tire suppliers and customer dis-satisfaction in third-party quality surveys such as J. D. Power IQS. Flat-spotting is of particular concern for slow-moving vehicle inventory parked for long periods at plants and/or dealership lots.OEMs often stipulate or recommend inventory storage practices for dealers that require physical movement of vehicles at some set duration to reduce the risk of tires developing permanent flat-spots. OEMs also provide component level flat-spotting requirements to tire manufacturers during sourcing and specification timing to secure their internal requirements and targets. The study in this paper initially determined real-world flat-spotting levels on an actual vehicle during the adverse summer months of Arizona. Tire uniformity measured on…
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New Method for Decoupling the Powertrain Roll Mode to Improve Idle Vibration

FCA US LLC-Syed F. Haider, Ahmad Abbas, Francisco Sturla
Published 2019-06-05 by SAE International in United States
Modern engines have high torque outputs and have low RPM due to increased demand for fuel efficiency. Vibrations caused by such engines have to be mitigated. Decoupling the roll mode from the remaining five rigid body modes results in a response which is predominantly about the torque roll axis (TRA) and helps reduce vibrations. Therefore, placing the mounts on the TRA early in the design phase is crucial. Best NVH performance can be obtained by optimizing the powertrain mount parameters viz; Position, Orientation and Stiffness. Many times, packaging restricts the mounts to be placed about the TRA resulting in degradation in NVH performance. Assuming that the line through the engine mount (Body side) centers is the desired TRA, we propose a novel method of shifting the TRA by adding mass modifying the powertrain inertia such that the new TRA is parallel to and on top to the desired TRA. This in turn will decouple the roll mode and reduce vibrations. This problem is formulated as an optimization problem. The numerical examples presented in this paper…
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Driveline NVH Integration of An NA Truck Program

American Axle & Manufacturing-Ying Peng, Zhenghong Shi, Christopher Folts, Gregory Kopp, Zhaohui Sun, Alexander Sandstrom
Published 2019-06-05 by SAE International in United States
In the current automotive industry, it is common that the driveline subsystem and components are normally from different automotive suppliers for OEMs. In order to ensure proper system integration and successful development of driveline system NVH performances, collaboration efforts between OEMs and suppliers are very demanding and important.In this paper, a process is presented to achieve successfulness in developing and optimizing vehicle integration through effective teamwork between a driveline supplier and a major OEM. The development process includes multiple critical steps. They include target development and roll down, targets being specific and measurable, comprehension of interactions of driveline and vehicle dynamics, accurate definition of sensitivity, proper deployment of modal mapping strategy, which requires open data sharing; and system dynamics and optimization. More specially, the supplier can work with OEM to seek the most cost-effective solutions, through tuning the driveline system dynamics to provide "quiet" frequency zone against vehicle sensitivity, to avoid normally needed costly suspension changes. Two case studies of a pick-up vehicle driveline program integration are used in this paper to illustrate the effectiveness…
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Rolling Bearing Dynamic Radial Load Test

ACBG Rolling Element Bearing Committee
  • Aerospace Standard
  • ARP5483/8B
  • Current
Published 2019-05-23 by SAE International in United States

This test method outlines the recommended machine function, fixtures, and procedures used to test airframe rolling element bearings for dynamic performance under steady unidirectional radial load and oscillatory motion. Bearings covered by this test method shall be ball, roller, or needle type in either annular or rod end configuration, used in airframe control applications.

 

On the Mechanical Design of the Rolling Road Addition to the CSUF Wind Tunnel

California State University, Fullerton-Ramitha Edirisinghe, Salvador Mayoral
Published 2019-04-02 by SAE International in United States
For ground effect aerodynamic studies in wind tunnels, boundary layer growth over the floor of the test section is a large concern. Many different techniques have been used to remove this boundary layer, of which creating a moving ground plane is considered the best option. By creating a moving floor in the test section, the ground plane speed can be set to that of the free stream air speed, thus removing the boundary layer or at the very least mitigating the boundary layer growth. Several studies detail the aerodynamic design concerns for such devices, but little information exists on the mechanical design concerns. This work reviews lessons learned during a design study of a rolling road for the wind tunnel at California State University, Fullerton (CSUF) mainly focusing on the motor specification and cooling system design. First, an overview of the major systems that comprise a rolling road apparatus are given. Then, initial constraints and free-body diagrams are presented detailing the forces experienced by the rolling road. From these free-body diagrams, analytical equations are presented…
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Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model

Honda R&D Co., Ltd.-Takeshi Hotaka, Tomonori Sakai, Hideki Miura
Published 2019-04-02 by SAE International in United States
At present, measurements of running resistance are conducted outdoors as a matter of course. Because of this, the ambient temperature at the time of the measurements has a considerable impact on the measurement data. The research discussed in this paper focused on the temperature characteristic of the tires and developed a new correction technique using a special rolling test apparatus. Specifically, using a tire rolling test apparatus that made it possible to vary the ambient temperature, measurements were conducted while varying the levels of factors other than temperature that affect rolling resistance (load, inflation pressure, and speed). Next, a regression analysis was applied to the data for each factor, and coefficients for a relational expression were derived, making it possible to derive a quadratic equation for the tire rolling resistance correction formula. It was verified that the application of the new correction formula reduced variation in running resistance from 2.7% (in the case of regulation correction) to 1.0%.In addition, in order to offer a simpler method of realizing the same correction, a technique for correction…
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Use of Cellphones as Alternative Driver Inputs in Passenger Vehicles

Clemson University-Chengshi Wang, Kim Alexander, Philip Pidgeon, John Wagner
Published 2019-04-02 by SAE International in United States
Automotive drive-by-wire systems have enabled greater mobility options for individuals with physical disabilities. To further expand the driving paradigm, a need exists to consider an alternative vehicle steering mechanism to meet specific needs and constraints. In this study, a cellphone steering controller was investigated using a fixed-base driving simulator. The cellphone incorporated the direction control of the vehicle through roll motion, as well as the brake and throttle functionality through pitch motion, a design that can assist disabled drivers by excluding extensive arm and leg movements. Human test subjects evaluated the cellphone with conventional vehicle control strategy through a series of roadway maneuvers. Specifically, two distinctive driving situations were studied: a) obstacle avoidance test, and b) city road traveling test. A conventional steering wheel with self-centering force feedback tuning was used for all the driving events for comparison. Based on the lane position and vehicle response data collected, the operators’ lane tracking capability during city road traveling was slightly inferior using a cellphone compared to traditional steering wheel. However, in extreme maneuvers like obstacle avoidance…
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Experimental Analysis of Suspension Kinematics and Compliance Characteristics of Sensitivities and Combined Load Cases with the Suspension Motion Simulator

Auto Mobil Forschung Dresden GmbH-Axel Gerhard
Dresden University of Technology-Chao Liu, Clemens Deubel, Junyu Zhou, Jan Kubenz, Günther Prokop
Published 2019-04-02 by SAE International in United States
The vehicle handling dynamics stands in the central place of the automotive developing processes. The accurately parameterized vehicle handling models play an important and useful role at different vehicle developing phases. At the early phase of vehicle development, they can be used to set the desired target by comparing the handling characteristics of competitors' vehicles. For the further developments of active systems, the right parameterized models are the basis to design the control systems in a virtual simulative environment. Therefore, there are the strong needs to develop a systematic methodology to parametrize the vehicle handling models, whose qualities should also be assured by the validation of field tests.The kinematics and compliance (KnC) behavior of the suspension is in the focus of this study. Compared with parameterization methods of other chassis subsystems, sensitivity analyses of suspension KnC testing conditions were very few in literatures published. With the help of the Suspension Motion Simulator (SMS) from MTS Systems Corporation, different factors of testing conditions (such as testing speeds, tire pressures, damper temperatures etc.) have been researched as…
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Development and Research of Laser Ranging Vehicle Driving Deviation Test System

Wuhan University of Technology-Xiaolong He, Can Yang
Published 2019-04-02 by SAE International in United States
Before the new car rolls from the line, due to assembly errors, inaccurate four-wheel positioning, etc., the vehicle will run off on a flat road, which will affect the driving comfort and safety. At present, most automobile manufacturers choose to perform the deviation test in the process of vehicle rolls from the line. Compared with other detection methods, the online deviation test system is developed with high precision of laser ranging, fast response and good reliability, which can realize fast and high-precision detection of vehicle deviation. In this paper, test system software is developed based on the LABVIEW, a variety of communication methods to build the communication system, using information check and queue task processing to control, to meet the test needs. Firstly, the calculation model of the deviation of the test system is established. Considering the influence of the driving angle in the measurement, the functional structure of the test system is built to determine the main functions of each part. In the system software design, it mainly includes the main test program and…
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Research on Exploring Effect of Stain Resisting Chemical Treatment on Automotive Fabric Parameters

Maruti Suzuki India, Ltd.-Riyaj Alam, Pankaj Maheshwari
Research-Sarita Kumari
Published 2019-04-02 by SAE International in United States
Fabrics play a vital role in defining the overall aesthetics of automotive interiors, primarily with fabric cleanliness. In this respect, the cleanliness of the fabric also becomes equally important. The fabric interior in a car is very prone to staining due to the spilling of water or any liquid substance over it. In order to protect and enhance the life of the fabric, various chemical treatments are suggested as fabric finishes. There are different chemical bases available for the same. Fluorocarbon base is the most effective treatment and is the focus of this study. This chemical treatment lowers the surface energy of the fabric by increasing the hydrophobicity of fabric. Hence, the liquid roll over the surface in the form of droplets by creating higher contact angle over the fiber surface.This study focuses on the effect of chemical treatment on the automotive fabric’s parameters, especially light color fabric. This study will provide a solution to the application of stain-resistant chemical treatment for improving cleanliness in the fabric, keeping a balance between the chemical treatment and…
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