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SAE International Journal of Commercial Vehicles
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Development of Noise Propensity Index (NPI) for Robust Brake Friction

SAE International Journal of Commercial Vehicles

Hyundai Motor Company-Jae Seol Cho, JongYun Jeong, Hyoung Woo Kim, Hwa Sun Lee, Yang Woo Park, Junghwan Lim, Yoonjae Kim
Korea University-Jinwoo Kim, Byung Soo Joo, Ho Jang
  • Journal Article
  • 2017-01-2529
Published 2017-09-17 by SAE International in United States
A semi-empirical index to evaluate the noise propensity of brake friction materials is introduced. The noise propensity index (NPI) is based on the ratio of surface and matrix stiffness of the friction material, fraction of high-pressure contact plateaus on the sliding surface, and standard deviation of the surface stiffness of the friction material that affect the amplitude and frequency of the stick-slip oscillation. The correlation between noise occurrence and NPI was examined using various brake linings for commercial vehicles. The results obtained from reduced-scale noise dynamometer and vehicle tests indicated that NPI is well correlated with noise propensity. The analysis of the stick-slip profiles also indicated that the surface property affects the amplitude of friction oscillation, while the mechanical property of the friction material influences the propagation of friction oscillation after the onset of vibration. An additional case study for noise reduction was carried out using commercial brake friction materials before and after the modification of NPI. The results of the case study based on in-vehicle noise tests indicate that a robust friction material can…
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Numerical Simulation Research on Pressure during Door Closure of Commercial Vehicle

SAE International Journal of Commercial Vehicles

ASCL, Jilin University-Xingjun Hu, Jiexun Cao
FAW Jiefang Qingdao Automobile Co. Ltd.-Sheng Li, Cunfu Chen
  • Journal Article
  • 2017-01-9182
Published 2017-06-28 by SAE International in United States
The magnitude of door closing force is important in vehicle NVH characters, and in most case, it is not fully studied by computer aided engineering (CAE) in an early developing stage. The research took a heavy-duty truck as the study object and used Computational Fluid Dynamic (CFD) method with dynamic mesh to analyze the flow field of the cabin during door closing process. The change trend of pressure with time was obtained, and the influence of different factors was studied. The experiments were conducted to verify the results. Results show that the velocity of closing door and the size of relief holes have a significant influence on cabin interior pressure, and greater velocity leads to larger the pressure in cabin. The initial angle of the door affects interior pressure less comparing with the velocity of closing door. The interior pressure could be reduced effectively with the method of decreasing the velocity of closing door and increasing the size of relief holes.
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Advanced Heat Transfer and Underhood Airflow Investigation with Focus on Continuously Variable Transmission (CVT) of Snowmobiles

SAE International Journal of Commercial Vehicles

BRP Finland Oy-Eetu Hurtig, Esa Väisänen, Joonas Mähönen
Graz University of Technology-Johannes Wurm, Christoph Hochenauer
  • Journal Article
  • 2017-01-9180
Published 2017-06-28 by SAE International in United States
The presented paper focuses on the computation of heat transfer related to continuously variable transmissions (CVTs). High temperatures are critical for the highly loaded rubber belts and reduce their lifetime significantly. Hence, a sufficient cooling system is inevitable. A numerical tool which is capable of predicting surface heat transfer and maximum temperatures is of high importance for concept design studies. Computational Fluid Dynamics (CFD) is a suitable method to carry out this task.In this work, a time efficient and accurate simulation strategy is developed to model the complexity of a CVT. The validity of the technique used is underlined by field measurements. Tests have been carried out on a snowmobile CVT, where component temperatures, air temperatures in the CVT vicinity and engine data have been monitored. A corresponding CAD model has been created and the boundary conditions were set according to the testing conditions. In a first step a simplified study is presented, to gain basic knowledge about the system, followed by a full underhood airflow simulation. The modelling process is presented in detail and…
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Damage Prediction for the Starter Motor of the Idling Start-Stop System Based on the Thermal Field

SAE International Journal of Commercial Vehicles

Chongqing Communication Institute-Minglei Du
Chongqing University-Zhongming Xu, Nengfa Tao, Tao Liang, Xiaojun Xia
  • Journal Article
  • 2017-01-9181
Published 2017-06-28 by SAE International in United States
A coupled magnetic-thermal model is established to study the reason for the damage of the starter motor, which belongs to the idling start-stop system of a city bus. A finite element model of the real starter motor is built, and the internal magnetic flux density nephogram and magnetic line distribution chart of the motor are attained by simulation. Then a model in module Transient Thermal of ANSYS is established to calculate the stator and rotor loss, the winding loss and the mechanical loss. Three kinds of losses are coupled to the thermal field as heat sources in two different conditions. The thermal field and the components’ temperature distribution in the starting process are obtained, which are finally compared with the already-burned motor of the city bus in reality to predict the damage. The analysis method proposed is verified to be accurate and reliable through comparing the actual structure with the simulation results. The approach in this paper provides the basis for optimizing the idling start-stop system in the future, and its key point lies in…
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Optimization of Front Wheel Drive Engine Mounting System for Third Order Shudder Improvement

SAE International Journal of Commercial Vehicles

Altair Engineering Inc.-Makarand Datar
Ford Motor Company-Kalyan Addepalli, Natalie Remisoski
  • Journal Article
  • 2017-01-9175
Published 2017-04-11 by SAE International in United States
Nowadays, the vehicle design is highly ruled by the increasing customer demands and expectations. In addition to ride comfort and vehicle handling, the Noise, Vibration and Harshness (NVH) behavior of the powertrain is also a critical factor that has a big impact on the customer experience. To evaluate the powertrain NVH characteristics, the NVH error states should be studied. A typical NVH event could be decoupled into 3 parts: source, path, and receiver. Take-off shudder, which evaluates the NVH severity level during vehicle take-off, is one of the most important NVH error states. The main sources of Front Wheel Drive (FWD) take-off shudder are the plunging Constant Velocity Joints (CVJ) on the left and right half shafts. This is because a plunging CVJ generates a third order plunging force with half shaft Revolution Per Minute (RPM), which is along the slip of the plunging CVJ. The primary path of take-off shudder is the Engine Mounting System (EMS), which isolates the vibration inputs from the vehicle body. A typical receiver of shudder is the passenger seat,…
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Accelerated Lab Test Methodology for Steering Gearbox Bracket Using Fatigue Damage and Reliability Correlation

SAE International Journal of Commercial Vehicles

Anna University-Vela Murali
Ashok Leyland Ltd.-N. Obuli Karthikeyan, R. Dinesh Kumar, V. Srinivasa Chandra
  • Journal Article
  • 2017-01-9177
Published 2017-04-11 by SAE International in United States
In the modern automotive sector, durability and reliability are the most common terms. Customers are expecting a highly reliable product but at low cost. Any product that fails within its useful life leads to customer dissatisfaction and affects the reputation of the OEM. To eradicate this, all automotive components undergo stringent validation protocol, either in proving ground or in lab. This paper details on developing an accelerated lab test methodology for steering gearbox bracket using fatigue damage and reliability correlation by simulating field failure. Initially, potential failure causes for steering gearbox bracket were analyzed. Road load data was then acquired at proving ground and customer site to evaluate the cumulative fatigue damage on the steering gearbox bracket. To simulate the field failure, lab test facility was developed, reproducing similar boundary conditions as in vehicle. Based on the damage analysis, customized lab test sequence was developed and field failure was simulated with the existing design samples. Reliability analysis was carried out and reliable life in lab test was correlated with the field. Lab cycle target for…
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Design and Analysis of Lifting Pusher Drop Axle for Heavy Commercial Vehicle

SAE International Journal of Commercial Vehicles

Ashok Leyland Ltd.-A Grinspan
M.Tech (CAD/CAM)-Jitesh Shukla
  • Journal Article
  • 2017-01-9176
Published 2017-04-11 by SAE International in United States
Lifting axles are auxiliary axles that provide increased load carrying capacity in heavy commercial vehicles. Lift axle gives better fuel efficiency as well as it reduces the operational costs by means of increasing the loading carrying capacity. These axles are raised when the vehicle is in unloaded condition, thus increasing the traction on remaining wheels and reducing the tire wear which in turn lower down the maintenance cost of the vehicle. Lifting height and force requires to lift the whole mechanism and are two main considerable factors to design the lifting axle mechanism. Although in India currently, the use of lift mechanism of single tire with continuous axle is more common. But in the case of pusher axle, continuous axle is unable to lift more after certain height because of the draft angle of the propeller shaft, and single tire axle which has less load carrying capacity up to 6T (Tons). Multi-axle vehicles have ‘pusher’ axle that is present in front of the drive tandem axle, which gives additional load carrying capacity for such vehicles.…
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Data Driven Calibration Approach

SAE International Journal of Commercial Vehicles

Ford Motor Company-Nahid Pervez, Ace Koua Kue, Adarsh Appukuttan, John Bogema, Michael Van Nieuwstadt
  • Journal Article
  • 2017-01-0607
Published 2017-03-28 by SAE International in United States
Designing a control system that can robustly detect faulted emission control devices under all environmental and driving conditions is a challenging task for OEMs. In order to gain confidence in the control strategy and the values of tunable parameters, the test vehicles need to be subjected to their limits during the development process. Complexity of modern powertrain systems along with the On-Board Diagnostic (OBD) monitors with multidimensional thresholds make it difficult to anticipate all the possible scenarios. Finding optimal solutions to these problems using traditional calibration processes can be time and resource intensive. A possible solution is to take a data driven calibration approach. In this method, a large amount of data is collected by collaboration of different groups working on the same powertrain. Later, the data is mined to find the optimum values of tunable parameters for the respective vehicle functions. This large scale data (terabytes) gives the engineers more samples to analyze and confidence in the calibration. A robust data analysis platform capable of handling large scale data and flexible enough to cater…
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Vibro-Impact Analysis of Manual Transmission Gear Rattle and Its Sound Quality Evaluation

SAE International Journal of Commercial Vehicles

Tongji University-Guangqiang Wu, Huwei Wu
  • Journal Article
  • 2017-01-0403
Published 2017-03-28 by SAE International in United States
Experimental schemes, frequency characteristics, subjective and objective sound quality evaluation and sound quality prediction model establishment of a certain mass-production SUV (Sport Utility Vehicle, SUV) manual transmission gear rattle phenomenon were analyzed in this paper. Firstly, vehicle experiments, including experiment conditions, vibration acceleration sensor and microphone arrangements and especial considerations in experiments, were described in detail. Secondly, through time-frequency analysis, broadband characteristics of manual transmission gear rattle noise were identified and vibro-impact of gear rattle occurs in the frequency range of 450~4000Hz on the vehicle idle condition and the creeping condition. Thirdly, based on bandwidth filtering processing of gear rattle noise, subjective assessment experiments by a paired comparison method were carried out. Evaluation results passed triangular loop verification and Spearman correlation coefficient examination, and then subjective annoyance results of each noise sample were calculated. Further, objective evaluation results, based on two physical acoustics parameters and six psychological acoustics parameters, were obtained respectively. Finally, comprehensive evaluation of subjective and objective results was analyzed by the MLR (Multiple Linear Regression, MLR) method. It’s concluded that AI (Articulation…
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Obstacle Avoidance Strategy and Implementation for Unmanned Ground Vehicle Using LIDAR

SAE International Journal of Commercial Vehicles

AVL Powertrain Engineering Inc-Yang Wang, Ankit Goila, Rahul Shetty, Mahdi Heydari, Ambarish Desai, Hanlong Yang
  • Journal Article
  • 2017-01-0118
Published 2017-03-28 by SAE International in United States
Regarding safety, obstacle avoidance has been considered as one of the most important features among ADAS systems for ground vehicles. However, the implementation of obstacle avoidance functions to commercial vehicles are still under progress. In this paper, we demonstrate a complete process of obstacle avoidance strategy for unmanned ground vehicle and implement the strategy on the self-developed Arduino based RC Car. In this process, the sensor LIDAR was used to detect the obstacles on the fore-path. Based on the measured LIDAR data, an optimized path is automatically generated with accommodation of current car position, obstacle locations, car operation capability and global environmental restrictions. The path planning is updated in real time while new or changing obstacles being detected. This algorithm is validated by the simulation results with the RC car. The comparison will be discussed at the end of this paper. The successful implementation of the proposed strategy demonstrates the feasibility of this obstacle avoidance methodology, which can be applied to commercial autonomous vehicle.
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