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Advancement in Vehicle Development Using the Auto Transfer Path Analysis

SAE International Journal of Passenger Cars - Mechanical Systems

Altair Engineering Inc.-Jianmin Guan, Dilip Mandal
General Motors Co.-Mallikarjuna Bennur
  • Journal Article
  • 2014-01-0379
Published 2014-04-01 by SAE International in United States
This paper presents the most recent advancement in the vehicle development process using the one-step or auto Transfer Path Analysis (TPA) in conjunction with the superelement, component mode synthesis, and automated multi-level substructuring techniques. The goal is to identify the possible ways of energy transfer from the various sources of excitation through numerous interfaces to given target locations. The full vehicle model, consists of superelements, has been validated with the detailed system model for all loadcases. The forces/loads can be from rotating components, powertrain, transfer case, chain drives, pumps, prop-shaft, differential, tire-wheel unbalance, road input, etc., and the receiver can be at driver/passenger ears, steering column/wheel, seats, etc. The traditional TPA involves two solver runs, and can be fairly complex to setup in order to ensure that the results from the two runs are consistent with subcases properly labeled as input to the TPA utility. However, auto TPA allows necessary data needed for the TPA analysis to be requested in a single frequency response analysis run. The TPA breaks down the total response to partial…
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Design and Development of Variable Valve Timing and Lift Mechanism for Improving the Performance of Single Cylinder Two Wheeler Gasoline Engine

Mahindra 2 Wheelers Ltd.-Shahnawaz Ahmed Khan, Prajod Ayyappath
Published 2014-04-01 by SAE International in United States
A small single cylinder 4 stroke gasoline engine varying capacity from 100cc to 1000cc generally used for two wheelers has a wide range of engine speeds during operation and may vary from 1000 RPM to 10000 RPM. Such variation in speed of engine demands variation in the valve timing and lift of engine at different speeds for optimum performance.The work aims at improving the performance of single cylinder two wheeler gasoline engine. The objective is to implement the novel variable valve timing and lift mechanism in the two wheeler single cylinder 4 stroke gasoline engine for the improvement in performance. The system design through kinematic calculations and 3D modeling, the prototyping with assembly, the functioning of system and its effect on the performance of engine are discussed in details. Valve timing and lift optimization was done using 1D simulation for performance prediction. The system includes a spring operated switching mechanism by which we achieve variation in valve timing and lift of intake valve at different speed range. The system is made compact to accommodate in…
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Development in the Acquisition of Vehicle Loads Integrated with a Rigid and Flexible Multi-Body Model

SAE International Journal of Commercial Vehicles

NAVECO Ltd.-Tongfu Liu, Liukai Yuan, Tangyun Zhang
School of Mechanical Engineering, NUST-Tao Wang, Liangmo Wang
  • Journal Article
  • 2014-01-0856
Published 2014-04-01 by SAE International in United States
As is known to all, the modeling of vehicles and durability simulation is becoming more accurate and more compatible with physical testing, resulting in shortening of the analysis process, and a lower cost. It would be more advantageous in the future to simulate the full vehicle system before the physical testing. Thus, in the analysis of vehicle durability performance, the need for more precise rigid and flexible vehicle modeling and more precise external loadings acquisition method is increasing.In view of the typical difficulties faced in the vehicle multi-body dynamics (MBD) simulation and in the associated loading extraction, this paper proposes a method to achieve accurate external vehicle loadings by virtual simulation. This method is performed based on the physical testing and compensates for the imperfections in the MBD modeling, thus being able to improve the quality of fatigue life prediction (FLP). Key technologies to implement this approach in this study include finite element analysis (FEA), MBD simulation and virtual iteration technique (VIT).A rigid and flexible multi-body dynamics model with less modes is constructed in order…
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Hybrid Brake System Control Strategy in Typical Transient Conditions

Tongji Univ.-Zhiting Zhu, Lu Xiong, Chi Jin
Published 2014-04-01 by SAE International in United States
The control in transient conditions when hydraulic brake and regenerative brake switch mutually is the key technical issue about electric vehicle hybrid brake system, which has a direct influence on the braking feel of driver and vehicle braking comfort. A coordination control system has been proposed, including brake force distribution correction module and motor force compensation module. Brake force distribution correction module has fixed the distribution results in hydraulic brake force intervention condition, hydraulic brake force evacuation condition and regenerative brake force low speed evacuation condition. Motor compensation module has compensated hydraulic system with motor system, which has fast and accurate response, thus the response of whole hybrid system has been improved. Simulation results in transient conditions show that the coordination control strategy can effectively reduce the fluctuations and deviations of total brake force, and improve braking feel of driver and vehicle braking comfort.
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A Novel Method for Side Slip Angle Estimation of Omni-Directional Vehicles

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

University of Wollongong-Boyuan Li, Haiping Du, Weihua Li
  • Journal Article
  • 2014-01-0303
Published 2014-04-01 by SAE International in United States
The omni-directional vehicle is an innovative vehicle, in which the in-wheel steering motor and in-wheel driving motor are integrated into each wheel of the vehicle so that each wheel can be independently controlled to have traction, braking, and turning motions to improve the vehicle's mobility, handling and stability. To realize good performance, various control strategies have been proposed, like the active steering control and the direct yaw moment control, where the accurate slip angle information is critical to these control strategies. However, in practice, the side slip angle is hard or expensive to be measured for a passenger vehicle, therefore, different estimation methods have been proposed in the literature. In this paper, a novel side slip angle estimation method is proposed for the omni-directional vehicle that has four independent steering motors. This method includes the estimation of total alignment torque and side slip angle, and only needs the measurements of steering angles and steering motor currents, which are available by using angle sensors and current sensors embedded with the in-wheel steering motors. Numerical simulations are…
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Multivariable Control of Dual Loop EGR Diesel Engine with a Variable Geometry Turbo

Cummins Inc.-Nassim Khaled, Michael Cunningham
Honeywell Automotive Software-Jaroslav Pekar, Adrian Fuxman, Ondrej Santin
Published 2014-04-01 by SAE International in United States
In this paper we consider the issues facing the design of a practical multivariable controller for a diesel engine with dual exhaust gas recirculation (EGR) loops. This engine architecture requires the control of two EGR valves (high pressure and low pressure), an exhaust throttle (ET) and a variable geometry turbocharger (VGT). A systematic approach suitable for production-intent air handling control using Model Predictive Control (MPC) for diesel engines is proposed. Furthermore, the tuning process of the proposed design is outlined. Experimental results for the performance of the proposed design are implemented on a 2.8L light duty diesel engine. Transient data over an LA-4 cycle for the closed loop performance of the controller are included to prove the effectiveness of the proposed design process. The MPC implementation process took a total of 10 days from the start of the data collection to build a calibrated engine model all the way through the calibration of the controller over the transient drive cycle.
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Comparison of Torque Vectoring Control Strategies for a IWM Vehicle

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Politecnico di Milano-Edoardo Sabbioni, Federico Cheli, Michele Vignati, Stefano Melzi
  • Journal Article
  • 2014-01-0860
Published 2014-04-01 by SAE International in United States
In recent years, concerns for environmental pollution and oil price stimulated the demand for vehicles based on technologies alternative to traditional IC engines. Nowadays several carmakers include hybrid vehicles among their offer and first full electric vehicles appear on the market. Among the different layout of the electric power-train, four in-wheel motors appear to be one of the most attractive. Besides increasing the inner room, this architecture offers the interesting opportunity of easily and efficiently distribute the driving/braking torque on the four wheels. This characteristic can be exploited to generate a yaw moment (torque vectoring) able to increase lateral stability and to improve the handling of a vehicle. The present paper presents and compares two different torque vectoring control strategies for an electric vehicle with four in-wheel motors. Performances of the control strategies are evaluated by means of numerical simulations of open and closed loop maneuvers. Energy demands of the two control strategies are also estimated.
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Parameter Identification of PMSM for EPS Based on an Improved MRAS Method

Jilin Univ.-Hu Zhang, JianWei Zhang, Konghui Guo
Published 2014-04-01 by SAE International in United States
Whether high-precision torque control or motor condition monitoring need accurate motor parameters. For the three parameters of surface-mounted permanent magnet synchronous motor (SPMSM), the voltage equation is rank-deficient. To solve this problem, some scholars proposed methods that build full rank equations with signal injection, but this will produce motor torque ripple, which is not suitable for application to the EPS. Therefore, this paper proposes a method based on MRAS to identify motor parameters step by step. The proposed two steps identification method can make the reference model full rank in every step, but the total decoupling between parameters identification processes cannot be realized for the assumption that the prior step result is the real value. It was found in experiment that this effect varies with the motor operating conditions. Therefore, this paper analyzes the sensitivity of the motor parameters and proposes a method to improve the accuracy of identification results by changing the weight of identification results according to the operating conditions. The performance of the proposed method was verified through experiment, and the accuracy…
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Extracting Situations with Uneasy Driving in NDS-Data

Volvo Cars-Tobias Karlsson, Magdalena Lindman, Jordanka Kovaceva, Bo Svanberg, Henrik Wiberg, Lotta Jakobsson
Published 2014-04-01 by SAE International in United States
Different types of driver workload are suggested to impact driving performance. Operating a vehicle in a situation where the driver feel uneasy is one example of driver workload. In this study, passenger car driving data collected with Naturalistic Driving Study (NDS) data acquisition equipment was analyzed, aiming to identify situations corresponding to a high driver's subjective rating of ‘unease’. Data from an experimental study with subjects driving a passenger car in normal traffic was used. Situations were rated by the subjects according to experienced ‘unease’, and the Controller Area Network (CAN) data from the vehicle was used to describe the driving conditions and identify driving patterns corresponding to the situations rated as ‘uneasy’. These driving patterns were matched with the data in a NDS database and the method was validated using video data.Two data mining approaches were applied. The first was based on an ensemble classifier on general variables derived from the CAN-data to predict the subjective rating of segments of the data. The second used hierarchical clustering with a distance metric based on the…
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Development of Accelerated Reliability Testing Method for Electric Vehicle Motor and Battery System

Hyundai Motor Co.-Dong-Hyun Ha, Soon-Cheol Park, Chun-Woo Shin
Published 2014-04-01 by SAE International in United States
Currently, the interest in accelerated reliability testing (ART) of electric vehicles parts has been increasing. In particular, an electric motor and battery are vital components of battery powered electric vehicles. The electric motor has two major roles, to discharge or charge battery when it is driven or braking. For analyzing the exact behavior mechanism of electric motor and predicting lithium-ion battery cell degradation, new accelerated reliability testing technology is required.This paper describes the results of research and development in new approach to reliability testing for electric vehicles. The methodology to measure a precise motor output torque of the rotating rotor using telemetry system was provided. The electric energy quantities as well as the used quantities of the electric power were also analyzed. The results of research and development in new approach to reliability testing for electric vehicles were systematized and reflected in development.
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