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SAE International Journal of Passenger Cars Mechanical Systems
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Design of the Linear Quadratic Control Strategy and the Closed-Loop System for the Active Four-Wheel-Steering Vehicle

SAE International Journal of Passenger Cars - Mechanical Systems

Wuhan University of Technology-Zhiyun Zhang, Miaohua Huang, Meixia Ji, Shuanglong Zhu
  • Journal Article
  • 2015-01-9107
Published 2015-05-05 by SAE International in United States
In the field of active safety, the active four-wheel-steering (4WS) system seems to be an attractive alternative and an effective tool to improve the vehicles' handling stability in lane-keeping control performance. Under normal using condition, the vehicle's lateral acceleration is comparatively small, and the mathematic relationship between the small side force excitation and the small slip angle of the tire is in the linear region. Furthermore, the effects of roll, heave, and pitch motions are neglected as well as the dynamic characteristics of the tires and suspension system in this work. Therefore, the linear quadratic control (LQC) theory is used to ensure that the output of the 4WS control system can keep track of the desired yaw rate and zero-sideslip-angle response can also be realized at the same time.Due to the development of Steer-by-Wire (SBW) technology, the driver's steering input can be easily converted into digital signals and calculated by the SBW conversion mechatronic control system, which utilize these digital signals to regulate the front and rear wheel steering angle to achieve the ideal steering…
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Prominence of Different Directions of Hub Forces and Moments in Structure-Borne Tire Noise

SAE International Journal of Passenger Cars - Mechanical Systems

Luleå University of Technology-Magnus Löfdahl, Arne Nykänen, Roger Johnsson
  • Journal Article
  • 2015-01-9106
Published 2015-05-01 by SAE International in United States
In the automotive industry, tire noise is an important factor for the perceived quality of a product. A useful method to address such NVH problems is to combine recordings with measurements and/or simulations into auralizations. An example of a method to create structure-borne tire noise auralizations is to filter recordings of hub forces and moments through binaural transfer functions experimentally measured from the hub of the car to an artificial head in the car cabin. To create authentic auralizations of structure-borne sound, all six degrees of freedom (DOFs) of hub forces and moments and transfer functions should be included. However, rotational DOFs are often omitted due to measurement difficulty, complexity, time, and cost. The objective was to find which DOF (or DOFs) is perceived as most prominent in structure-borne tire noise. An auralization model of interior structure-borne tire noise was used. An auralization including all DOFs was compared with auralizations lacking one DOF at a time in a listening test. Auralizations lacking either all translational DOFs or all rotational DOFs were also included. Results from…
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Experimental Study on Continuous ABS Operation in Pure Regenerative Mode for Full Electric Vehicle

SAE International Journal of Passenger Cars - Mechanical Systems

Delft University of Technology-Barys Shyrokau
Flanders' Drive-Jasper De Smet, Johan Theunissen
  • Journal Article
  • 2015-01-9109
Published 2015-05-01 by SAE International in United States
Anti-lock braking functions of electric vehicles with individual wheel drive can be effectively realized through the operation of in-wheel or on-board motors in the pure regenerative mode or in the blending mode with conventional electro-hydraulic anti-lock braking system (ABS). The regenerative ABS has an advantage in simultaneous improvement of active safety, energy efficiency, and driving comfort. In scope of this topic, the presented work introduces results of experimental investigations on a pure electric ABS installed on an electric powered sport utility vehicle (SUV) test platform with individual switch reluctance on-board electric motors transferring torque to the each wheel through the single-speed gearbox and half-shaft. The study presents test results of the vehicle braking on inhomogeneous low-friction surface for the case of ABS operation with front electric motors. The performed tests confirm considerable reduction of braking distance and accurate tracking of the reference slip as compared with the vehicle braking without ABS. Hence the pure electric ABS can be considered as an efficient alternative to anti-lock braking systems with friction brakes only.
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The Thermal and Aerodynamic Development of a Cooling and Heat Resistance Package for a New Hybrid Sports Car

SAE International Journal of Passenger Cars - Mechanical Systems

Honda R & D Americas Inc-Thomas Ramsay, Timothy Juan, James McKillen
Honda R&D Co., Ltd.-Yasuyuki Onishi
  • Journal Article
  • 2015-01-1526
Published 2015-04-14 by SAE International in United States
A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept. The experimental and computational developments of ten air cooled-heat exchangers are described with the tradeoffs that were required during the development process. Since the cooling and heat resistance package was being developed as the vehicle…
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EPOSIL® for Automotive Suspension Components, Coils Springs and High Pressure Vessels

SAE International Journal of Passenger Cars - Mechanical Systems

Qip Sarl-Patricia Djomseu
Sardou Societe Anonyme-Max Sardou
  • Journal Article
  • 2015-01-1314
Published 2015-04-14 by SAE International in United States
SARDOU SAS has developed highly stressed composites parts for 35 years. SARDOU SAS and QUALITY INDUSTRIAL PRODUCT invented composite coils springs in 2002. Developing composite coils springs, we have faced a big challenge, how to increase the short life expectancy of this highly stressed structure?We have identified that the weak point, in composite coils springs, is its epoxy matrix. In fact, during heavy loading, the matrix undergoes micro cracks. Then, during fatigue, micro cracks propagate and merge, transforming the matrix into a fine powder. The composite coil suspension springs, using, classic epoxy, where ruined after only 100,000 cycles in the best cases. The fact to integrate “functionalized silica aggregates”, in the matrix, enable the springs to exceed 1,000,000 cycles, with the same spring design. In addition, the spring stiffness has increased by 6% and the thermal set has reduced by 1.6%. Based on these results we have worked, over 7 years, to develop, refine, and improve the efficiency and to reduce the cost of our technology.
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A Computational Approach to Assess Buffeting and Broadband Noise Generated by a Vehicle Sunroof

SAE International Journal of Passenger Cars - Mechanical Systems

Exa Corporation-Mohammed Meskine, Sivapalan Senthooran, Andrew Bissell, Gana Balasubramanian, Robert Powell
Jaguar Land Rover-Nicholas Oettle
  • Journal Article
  • 2015-01-1532
Published 2015-04-14 by SAE International in United States
Car manufacturers put large efforts into reducing wind noise to improve the comfort level of their cars. Each component of the vehicle is designed to meet its individual noise target to ensure the wind noise passenger comfort level inside the vehicle is met. Sunroof designs are tested to meet low-frequency buffeting (also known as boom) targets and broadband noise targets for the fully open sunroof with deflector and for the sunroof in vent position. Experimentally testing designs and making changes to meet these design targets typically involves high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the use of a reliable numerical prediction capability early in the vehicle design process.In the past, a computational approach based on a Lattice Boltzmann Method has been extensively validated for assessing the wind noise performance of mirrors, wipers, underbody designs and buffeting performance of sunroofs and open side windows. This paper presents the use of this computational approach on the Range…
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Development of Feedback-Based Active Road Noise Control Technology for Noise in Multiple Narrow-Frequency Bands and Integration with Booming Noise Active Noise Control System

SAE International Journal of Passenger Cars - Mechanical Systems

Honda R&D Co., Ltd.-Kosuke Sakamoto, Toshio Inoue
  • Journal Article
  • 2015-01-0660
Published 2015-04-14 by SAE International in United States
When a vehicle is in motion, noise is generated in the cabin that is composed of noise in multiple narrow-frequency bands and caused by input from the road surface. This type of noise is termed low-frequency-band road noise, and its reduction is sought in order to increase occupant comfort. The research discussed in this paper used feedback control technology as the basis for the development of an active noise control technology able to simultaneously reduce noise in multiple narrow-frequency bands. Methods of connecting multiple single-frequency adaptive notch filters, a type of adaptive filter, were investigated. Based on the results, a method of connecting multiple filters that would mitigate mutual interference caused by different controller transmission characteristics was proposed. This method made it possible to implement controllers with amplitude and phase characteristics in multiple narrow-frequency bands corresponding to design values, and to achieve the target noise-reduction. Additionally, in feedback-based road noise control, the amplitude of the control output signal changes drastically depending on the frequency characteristics of the road surface. When this technology was integrated with…
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FEA Development of Spot Weld Modeling with Fracture Forming Limit Diagram(FFLD) Failure Criteria and Its Application to Vehicle Body Structure

SAE International Journal of Passenger Cars - Mechanical Systems

General Motors Co.-Hwawon Lee, Parvath Police, Lisa Koch, Rajmouli Komarivelli, Brice Willis
  • Journal Article
  • 2015-01-1316
Published 2015-04-14 by SAE International in United States
Spot weld separation in vehicle development stage is one of the critical phenomena in structural analyses regarding quasi-static test condition, like roof strength or seat/belt pull. It directly reduces structural performance by losing connected load path and occasionally introduces tearing on surrounding sheet metals. Traditionally many efforts have been attempted to capture parent metal ductile fracture, but not applied to spot weld separations in automotive FEA simulations. [1,2,3]This paper introduces how to develop FFLD failure criteria from a series of parametric study on ultra high strength sheet steel and deals with failure criteria around spot weld and parent metal. Once the fracture strains for sheet steels are determined, those developed values were applied to traditional spot weld coupon FEA simulations and tests. Full vehicle level roof strength FEA simulations on a typical automotive body structure were performed and verified to the physical tests.Developed FFLD curves have been used for both spot weld and parent metal and good correlations have been achieved. Various mesh patterns and sizes around spot welds have been investigated. Finally, an optimized…
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Establishment of Performance Design Process for Vehicle Sound-Roof Packages Based on SEA Method

SAE International Journal of Passenger Cars - Mechanical Systems

Honda R&D Co., Ltd.-Hiroko Tada
  • Journal Article
  • 2015-01-0664
Published 2015-04-14 by SAE International in United States
The process for setting the marketability targets and achievement methods for automotive interior quietness (as related to air borne noise above 400Hz, considered the high frequency range) was established. With conventional methods it is difficult to disseminate the relationship between the performance of individual parts and the overall vehicle performance. Without new methods, it is difficult to propose detailed specifications for the optimal sound proof packages.In order to make it possible to resolve the individual components performance targets, the interior cavity was divided into a number of sections and the acoustic performance of each section is evaluated separately. This is accomplished by evaluating the acoustical energy level of each separate interior panel with the unit power of the exterior speaker excitation.The applicability of the method was verified by evaluating result against predicted value, using the new method, during actual vehicle operation. The difference between predicted interior cavity sound pressure level (SPL) and that of measured was less than 3dB. In addition, the difference in the level of reduction in interior cavity SPL by countermeasure between…
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On the Coupling Stiffness in Closed-Loop Coupling Disc Brake Model through Optimization

SAE International Journal of Passenger Cars - Mechanical Systems

Tsinghua University-Yongchang Du, Yujian Wang
Yanshan University-Pu Gao, Yingping Lv
  • Journal Article
  • 2015-01-0668
Published 2015-04-14 by SAE International in United States
The study and prevention of unstable vibration is a challenging task for vehicle industry. Improving predicting accuracy of braking squeal model is of great concern. Closed-loop coupling disc brake model is widely used in complex eigenvalue analysis and further analysis. The coupling stiffness of disc rotor and pads is one of the most important parameters in the model. But in most studies the stiffness is calculated by simple static force-deformation simulation. In this paper, a closed-loop coupling disc brake model is built. Initial values of coupling stiffness are estimated from static calculation. Experiment modal analysis of stationary disc brake system with brake line pressure and brake torques applied is conducted. Then an optimization process is initiated to minimize the differences between modal frequencies predicted by the stationary model and those from test. Thus model parameters more close to reality are found. Unstable mode prediction results using parameters before / after optimization are compared with those from brake noise bench test. The results after parameter optimization are in good correlation with test result and illustrate obvious…
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