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Formula SAE Data Acquisition and Detailed Analysis of a Lap

Georgia Southern University-Connor M. Ashford, Aniruddha Mitra
  • Technical Paper
  • 2020-01-0544
To be published on 2020-04-14 by SAE International in United States
Formula Society of Automotive Engineers (FSAE) International is a student design competition organized by SAE. The student design involves engineering and manufacturing a formula style racecar and evaluating its performance. Testing and validation of the vehicle is an integral part of the design and performance during the competition. At the collegiate level the drivers are at the amateur level. As a result, the human factor plays a significant role in the outcome of the dynamic events. In order to reduce the uncertainty factor and improve the general performance, driver training is necessary. Instead of overall performance of the driver based on individual lap, our current research focuses on the more detailed components of the driver’s actions throughout different sections of the lap. A complete lap consists of several components, such as, straight line acceleration and braking, max and min radius cornering, slalom or “S” movements, and bus stops or quick braking and turning. In order to evaluate the performance of each driver in each of these components, an AiM data acquisition system is mounted in…
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Development and Application of a Collision Avoidance Capability Metric

AAA Northern California Nevada & Utah-Paul Wells, Atul Acharya
Dynamic Research Inc.-Jordan Silberling, Joseph Kelly, John Lenkeit
  • Technical Paper
  • 2020-01-1207
To be published on 2020-04-14 by SAE International in United States
This paper describes the development and application of a newly developed metric for evaluating and quantifying the capability of a vehicle/controller (e.g., Automated Vehicle or human driver) to avoid collisions in nearly any potential scenario, including those involving multiple potential collision partners and roadside objects. At its core, this Collision Avoidance Capability (CAC) metric assesses the vehicle’s ability to avoid potential collisions at any point in time. It can also be evaluated at discrete points, or over time intervals. In addition, the CAC methodology potentially provides a real-time indication of courses of action that could be taken to avoid collisions. The CAC calculation evaluates all possible courses of action within a vehicle’s performance limitations, including combinations of braking, accelerating and steering. Graphically, it uses the concept of a “friction ellipse”, which is commonly used in tire modeling and vehicle dynamics as a way of considering the interaction of braking and turning forces generated at the tire contact patches. When this concept is applied to the whole vehicle, and the actual or estimated maximum lateral and…
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Improving EV customer experience using Sound Enhancement

General Motors-Frank Valeri, Glenn Pietila
  • Technical Paper
  • 2020-01-1361
To be published on 2020-04-14 by SAE International in United States
Electric Vehicles are typically thought of as being quiet and refined, but they do come with some unique N&V challenges. Some of these challenges include a natural sound that can be undesirable due to its tonal nature, presence of high frequency, discontinuities in sound, and characteristics and levels that do not always naturally increase with motor torque and vehicle speed. One approach to address those challenges is Electric Vehicle Sound Enhancement (EVSE) which is a software feature embedded within the infotainment system. EVSE can be used to improve the perception of the vehicle by enhancing the preferred natural sounds of the vehicle, masking unusual and annoying components of the sound and aurally conveying information related to the vehicle performance. A jury study was conducted to better understand how EVSE can be used to accomplish this. This paper will summarize a typical EVSE system and highlight some of the tools and methods that can be used to develop an EVSE tuning that mitigates the unpleasant sounds and enhances the customer experience without completely changing the vehicle…
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Nonlinear Model Predictive Control of Autonomous Vehicles Considering Dynamic Stability Constraints

Tongji University-Xunjie Chen, Guangqiang Wu, Meng Ren
  • Technical Paper
  • 2020-01-1400
To be published on 2020-04-14 by SAE International in United States
The autonomous vehicle performance is increasingly highlighted in many highway driving scenarios, which leads to more priorities to vehicle stability as well as tracking accuracy. In this paper, a nonlinear model predictive controller for autonomous vehicle trajectory tracking is designed and verified through a real-time driving simulator of a virtual test track. The dynamic stability constraints of nonlinear model predictive control (NLMPC) are obtained by a novel quadrilateral stability region criterion instead of the conventional phase plane method using the double-line region. First, a typical lane change scene of overtaking is selected and a new composited trajectory model is proposed as a reference path that combines smoothness of sine wave and comfort of linear functional path. Reference lateral velocity, azimuth angle, yaw rate, and front wheel steering angle are subsequently taken into account. Then, by establishing a nonlinear vehicle dynamics model where Magic Formula of nonlinear tire model is adapted, the quadrilateral vehicle stability region is defined in consideration of designed velocity, road adhesion coefficient, and front wheel steering angle. Working condition-variant constraints determined by…
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Automated highway driving motion decision based on optimal control theory

Chongqing University-Wei Yang, Zheng Ling, Yinong Li
  • Technical Paper
  • 2020-01-0130
To be published on 2020-04-14 by SAE International in United States
According to driving scenarios, intelligent vehicle is mainly applied on urban driving, highway driving and close zone driving, etc. As one of the most valuable developments, automated highway driving has great progress. This paper focuses on automated highway driving decision, and considering decision efficiency and feasibility, a hierarchical motion planning algorithm based on dynamic programming was proposed, and simultaneously, road coordinate transformation methods were developed to deal with complex road conditions. At first, all transportation user states are transformed into straight road coordinate to simplify modeling and planning, then a set of candidate paths with Bezier form was developed and with the help of obstacles motion prediction, the feasible target paths with collision-free were remains, and via comparing vehicle performance for feasible path, the optimal driving trajectory was generated. At last, the optimal control model was applied to obtain the motion parameters, which were regarded as the control target for lower level controller. A three-lane highway simulations was designed, and the results demonstrated that the proposed algorithm was valid to avoid obstacles with given speed,…
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The Resolution of 8th Order Whining Noise Issue for a Battery Electric Vehicle

China FAW Group-Jingting feng, Jianjiao DENG, Yingjie LIU, Hangsheng hou, Ryusuke oka
  • Technical Paper
  • 2020-01-1269
To be published on 2020-04-14 by SAE International in United States
With significant improvement in overall vehicle NVH performance in recent years, sound quality has become an important customer concern. In search of excellence in customer satisfaction with Battery electric vehicles (BEV’s), optimizing the e-motor noise is one of the most effective ways to improve vehicle sound quality. This paper aims to resolve the whining noise issue from a permanent magnet synchronous motor (PMSM) during the development of a BEV program. The order of the most critical whining noise from an e-motor on market today is normally the 48th order, which can be mitigated by implementing sound package material on the motor casing. In this work, however, the 8th order is found to be the most critical issue which is perceived as the whining noise with the frequency range under 600Hz. For such a low frequency content, sound package treatment has little effect. With subjective evaluation and analysis of testing results, it is found that the worst case is associated with the peak of the 8th order. The 8th order electromagnetic force is induced by the…
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A Study on the Development of the CPA (Centrifugal Pendulum Absorber)Reducing the Rattle & Booming Noise in the Manual Transmission Vehicle

Ukjin Kim-Ukjin Kim
  • Technical Paper
  • 2020-01-0397
To be published on 2020-04-14 by SAE International in United States
In recent years, the automotive engine strategies are forced on downsizing and down speeding to enhance fuel economy and reduce the emission. These make torque increase significantly in order to improve the vehicle performance, especially in diesel engines. At this time, the torsional damper performs the most important role in the driveline NVH of the manual transmission system. The clutch disk with torsional dampers is not easy to be applicable to the high torque of low speed RPM range. And DMF with sufficient isolation of vibrations of driving system includes disadvantages of the expensive cost, delayed response, and engine NVH aspect deteriorated due to increase of angular acceleration of engine. This paper presents that the Centrifugal Pendulum Absorber (CPA) is applied to maximize the isolation and to compensate for the disadvantages of DMF and SMF system. Furthermore, CPA was developed for the first time in the world on SMF clutch discs in manual transmission.
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Development and Demonstration of a New Range-Extension Hybrid Powertrain Concept

Tongji University-Zhiyu Han, Zhenkuo Wu, Xiaojie Gao, Yongzheng Sun, Runyu Ni, Jian Feng, Jian zhong, Xinbo Chen, Zhiguo Zhao, Zhuoping Yu
  • Technical Paper
  • 2020-01-0845
To be published on 2020-04-14 by SAE International in United States
A new range-extension hybrid powertrain concept, namely the Tongji Extended-range Hybrid Technology (TJEHT) was developed and demonstrated in this study. This hybrid system is composed of a direct-injection gasoline engine, a traction motor, an integrated starter-generator (ISG) motor, and a transmission. In addition, an electronically controlled clutch between the ISG motor and engine, and an electronically controlled synchronizer between the ISG motor and transmission are also employed in the transmission case. Hence, this system can provide six basic operating modes including the single-motor driving, dual-motor driving, serial driving, parallel driving, engine-only driving and regeneration mode depending on the engagement status of the clutch and synchronizer. Importantly, the unique dual-motor operation mode can improve vehicle acceleration performance and the overall operating efficiency. The hybrid system controls and energy management strategy based on equivalent fuel consumption minimization were developed and validated. The choice of an operating mode is optimized according to the drivers’ demand, actual vehicle state, operation conditions, and other boundary conditions. In this paper, the powertrain architecture and operating modes are firstly described. Secondly, the…
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Vehicle Performance Analysis of Modern Lithium Battery Chemistries for 48V Mild Hybrid Passenger Car

University of Nottingham-Khaled Alnamasi, Simon Terry, Antonino La Rocca, Alasdair Cairns
  • Technical Paper
  • 2020-01-0439
To be published on 2020-04-14 by SAE International in United States
Through improving the 48V hybrid vehicle archetype, governmental emission targets could be more easily met without incurring the high costs associated with increasing levels of electrification. The braking energy recovery function of hybrid vehicles is recognised as an effective solution to reduce emissions and fuel consumption in the short to medium term. The aim of this study was to evaluate methods to maximise the braking energy recovery capability of the 48V hybrid electric vehicle over pre-selected drive cycles using appropriately sized electrified components. The strategy adopted was based upon optimising the battery chemistry type via specific power capability, so that overall brake power is equal to the maximum battery charging power in a typical medium-sized passenger car under typical driving. This will maximise the regenerative braking energy whilst providing a larger torque assistance for a lower battery capacity. Dynamic simulation models were developed using GT-DRIVE software, emulating a mid-sized car with a 48V battery, and different turbocharged gasoline engines with motor generator unit positions along a drivetrain. The battery pack was developed using an 8…
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Strategy for Optimizing an F1 Car’s Performance based on FIA Regulations

Oxford Brookes University-Karan Bopaiah, Stephen Samuel
  • Technical Paper
  • 2020-01-0545
To be published on 2020-04-14 by SAE International in United States
With the introduction of the V6 engines in Formula 1, in 2014, the sport aimed to close the gap between the automotive engine and high-performance motorsport engines in the area of fuel economy. A set of very challenging engineering regulations were introduced by the FIA to restrict the power from the Internal Combustion Engine (ICE), while allowing for more power to be harvested through energy recovery systems. Although progress has been made in developing a highly efficient powertrain, the limit to which this system can be pushed to is still unknown due to a significant gap between the technological choices available and the optimal control strategy used. This study investigated an engine-powertrain model of an F1 car with real world driver data for estimating the vehicle’s full throttle performance. The work used engine and drive-cycle simulation-modeling tools to build a representative car model which complied with the 2019 FIA regulations, in conjunction with real world data to identify the most critical parameter such as the gear shift strategy and the maximum energy recovered, stored and…