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Optimization of the Aerodynamic Lift and Drag of LYNK&CO 03+ with Simulation and Wind Tunnel Test

Geely Automobile Research Institute-Qian Feng, Biaoneng Luo, Huixiang Zhang, Hong Peng, Zhenying Zhu, Zhi Ding, Ling Zhu
Dassault Systemes(Shanghai) Information Technology Co.-Weiliang Xie, Bo Li, Xiaowei Zhao
  • Technical Paper
  • 2020-01-0672
To be published on 2020-04-14 by SAE International in United States
Based on the first sedan of the LYNK&CO brand from Geely, a high performance configuration with the additional aerodynamic package was developed. The aerodynamic package including the front wheel deflector, the front lip, the side skirt, the rear spoiler and the rear diffuser, were upgraded to generate enough aerodynamic downforce for better handing stability, without too much compromising of the aerodynamic drag of the vehicle to keep a low fuel consumption. Simulation approach with PowerFLOW, combined with the design space exploration method were used to optimize both of the aerodynamic lift and drag. Wind tunnel test was also used to firstly calibrate the simulation results and finally to validate the optimized design. The results turn out to be appropriate trade-off between the lift and the drag to meet the aerodynamics requirement, and a consistently good matching between the simulation and test.
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Road Noise Evaluation by Sound Quality Simulation Module

Geely Automobile Research Institute-Perry Gu, Jie Mao, Zhidong Chen, Zhi Ding, Lei Cheng, Zhenying Zhu, Hong Peng
  • Technical Paper
  • 2020-01-1275
To be published on 2020-04-14 by SAE International in United States
An objective evaluation of sound quality is a technical bridge connecting sound pressure level (SPL) and human auditory sensation. In this paper, an algorithm is proposed for calculating objective evaluation parameters of sound quality (including loudness, sharpness and articulation index), considering acoustic characteristics of human external ear, middle ear and inner ear to reflect auditory sensation. A sound quality simulation (SQS) module is coded according to the algorithm. The module is used for evaluating sound quality of road noise from an SUV in three steps. Firstly, interior noise is predicted by integrating finite-element method (FEM), hybrid FE-SEA method, and statistical energy analysis (SEA) for low frequency (20~315 Hz), medium frequency (315~500 Hz), and high frequency (>500 Hz) in 1/3 octave band, respectively. The predicted interior noise SPLs are compared with the measured results, with deviations less than 3dB in average. Secondly, the sound quality parameters are calculated using the predicted SPLs in the SQS module. The predicted and measured loudness, sharpness, and articulation index are compared, with average deviations less than 5%. Finally, the predicted…
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Multi-objective discrete robust optimization for vehicle front-end structure design under pedestrian head impact

Geely Automobile Research Institute-Xiaojiang Lv, Heping Yang, Haiyang Zhang, Dayong Zhou, Pengyun Gu
Hunan University-Fei Lei, Xiaojiang Lv
  • Technical Paper
  • 2020-01-0934
To be published on 2020-04-14 by SAE International in United States
Vehicle front-end structures have drawn considerable attention for their significant advantages in the protection of head which is the most vulnerable body part in pedestrian accidents. Optimization design for vehicle front-end structures has proven rather essential and been extensively used to improve the performance of head protection. Nevertheless, an optimal design could become less meaningful or even unacceptable when some uncertainties present. Furthermore, the traditional discrete robust optimization is mostly focused on single objective problems. In fact, the design of front-end structures for pedestrian head impact is indeed a multi-objective discrete optimization problem. This study aimed to explore how to minimize the injury of the head involving uncertain environment and multi-objective discrete optimization problem. For this purpose, the paper proposes a novel multi-objective discrete robust optimization (MODRO) algorithm to minimize the injury of head involving uncertainties in pedestrian-vehicle collisions. MODRO algorithm is achieved by coupling grey relational analysis (GRA) and entropy method with Taguchi approach. Taguchi approach is utilized to perform experiments and analysis of means (ANOM) is used to predict the optimum design. The…
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The Aural Discomfort Analysis and Control In the Instant the Door Closes

Geely Automobile Research Institute-Mao Guang Jun, Youqiang Cao, Jun Zhang, Kaige Zhang, Gang Yang
  • Technical Paper
  • 2020-01-1260
To be published on 2020-04-14 by SAE International in United States
With the improvement of the vehicle air leakage performance, the aural discomfort phenomenon appeared in the instant the door closes. The studies for closing door sound quality have been occurred, but there is little literature on the study of the aural discomfort due to the air pressure fluctuation over a very short period of time. In this paper, the relationship between the air leakage under positive pressure and the aural discomfort based on the air pressure fluctuations in the instant the door closes was systematically studied through a large number of objective test and subjective evaluation of the vehicles. And this paper theoretically deduces the relationship of the air pressure fluctuation inside the car with the closing door speed, the ratio of door area to passenger compartment volume, the vehicle air leakage, the cross-sectional area of the vehicle, the decompression air vent area at the moment the door closes. Then the objective test data and CAE analysis validate completely the inference. In this paper, it puts forward the human aural comfort air pressure threshold value…
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Emission Control System Designing to Meet China 6

Geely Automobile Research Institute-Qingmao Zhang, Xiangfei Ren, Xiangke Wu, Jin Li, Chu Chen, Jiangwei Wang
Johnson Matthey Chemical Ltd.-Yinglei Sun, Hongyu Ji, Shengdian Chen
Published 2018-09-10 by SAE International in United States
China 6 will be implemented from Jul 1st 2020, containing two norms, China 6a and China 6b. China 6a brings an introduction of the WLTC and a PN limit of 6 x 1011 #/km. Emissions limits of THC, CO and NOx, in China 6a are similar to China 5. Overall China 6a sets a similar emissions challenge to Euro 6d. In areas where China 6b is introduced before national roll out, we will see a further tightening in gaseous emissions to around half of China 6a levels for THC, CO and NOx. This therefore presents a very challenging situation for emissions control system design, particularly because of both the stringent gaseous requirement in China 6b and the PN requirement.In this paper, one development stage vehicle, equipped with a 1.5 L Gasoline Direct Injection (GDI) engine, was chosen for investigation. Firstly, after a calibration modification, 3 TWC systems with variable PGM loading were evaluated. The results showed the systems with a PGM loading higher than 40 g/ft3 for the front brick, plus a rear brick with…
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A Comparative Study of Vehicle Front Shape Based on Multi-Objective Optimization for Minimizing Injury Risks in Pedestrian and Cyclist Impact

Geely Automobile Research Institute-Xiaojiang Lv, Weiguo Liu, Dayong Zhou, Haiyang Zhang
Hefei University of Technology-Xianguang Gu
Published 2018-04-03 by SAE International in United States
This study aims to explore the influence of a vehicle front-end shape on pedestrian and cyclist injuries. The injuries of head, upper leg and lower leg based on 50th human model are considered as design response. A multi-objective optimization approach is developed to design and optimize the front shape for minimizing injury risks of pedestrian and cyclist in this study. The numerical models of pedestrian-vehicle and cyclist-vehicle impact is constructed and validated first. Then, the optimal Latin hypercube sampling (OLHS) method is adopted for design of experiment (DOE) and the surrogate model is constructed through radial basis function (RBF). The optimal problems involving a number of objectives are solved by the multi-objective particle swarm optimization (MOPSO) algorithm in this study. With the optimization design of vehicle front shape by using pedestrian-vehicle impact and cyclist-vehicle impact, the optimal front shape is obtained although some design variables strongly compete with each other.
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Application of Slope Sensor in Hill-Start to AMT (Automated Manual Transmission) Vehicles

Geely Automobile Research Institute-Yong Chen, Lishu Guo
Jilin University-Hongqing Chu, Bingzhao Gao, Hong Chen
Published 2015-04-14 by SAE International in United States
In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock. In addition, it can also avoid backward sliding and engine over-speed effectively. Furthermore, hill-start with low-cost slope sensor and optimal clutch controller can reduce clutch wear, extend the life of dry clutch…
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Analysis and Optimization for Cracking of a Steering Tie Rod based on Arc Length Algorithm

Geely Automobile Research Institute-Yongsheng Li
Published 2013-04-08 by SAE International in United States
An investigation was performed on steering tie rod for cracking with strength and buckling analysis theory, which showed a low risk of failure. In order to solve this problem, a “necking down” method was used to optimize the length and location by Arc Length Algorithm, which was proved by pressing and impact test. It is shown that simulation results are in consistency with tests, “necking down” can alleviate cracking and improve quality efficiently on the premise of mere decrease in pressure resistance.
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Stratified Mixture Formation and Combustion Process for Wall-guided Stratified-charge DISI Engines with Different Piston Bowls by Simulation

Geely Automobile Research Institute-Yi You, Jingyan Hu
Tongji Univ.-Qianwang Fan, Zongjie Hu, Jun Deng, Liguang Li
Published 2010-04-12 by SAE International in United States
This paper presents the simulation of in-cylinder stratified mixture formation, spray motion, combustion and emissions in a four-stroke and four valves direct injection spark ignition (DISI) engine with a pent-roof combustion chamber by the computational fluid dynamics (CFD) code. The Extended Coherent Flame Combustion Model (ECFM), implemented in the AVL-Fire codes, was employed. The key parameters of spray characteristics related to computing settings, such as skew angle, cone angle and flow per pulse width with experimental measurements were compared.The numerical analysis is mainly focused on how the tumble flow ratio and geometry of piston bowls affect the motion of charge/spray in-cylinder, the formation of stratified mixture and the combustion and emissions (NO and CO₂) for the wall-guided stratified-charge spark-ignition DISI engine. But due to the fuel injected during compression stroke, the effect of intake ports and exhaust ports were not taken into consideration in this study. It is found that the geometry of piston bowls has a major effect on the mixture stratification in-cylinder, the combustion process and others. In addition, the characteristics of the…
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