Changan Automobile Engineering Institute

Chongqing, China

Changan Automobile Engineering Institute

Chongqing, China
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Peng L.,Changan Automobile Engineering Institute | Wang Z.,Changan Automobile Engineering Institute | Gu J.,Changan Automobile Engineering Institute
SAE Technical Papers | Year: 2016

Body structure design needs to meet multi-attributes requirements such as global bend stiffness/modal, torsion stiffness/modal, Noise and velocity transfer functions (NTF/VTF), and others. Computer-aided engineering (CAE) is a significant way to enhance the accuracy of design results. However, it also brings computation burden for optimization. In order to improve the performance and reduce the weight of automobile body structure, this paper presents a novel process of body CAE multi-attributes optimization. Four significant phases are described: 1) Sensitivity analysis for each body CAE performance, 2) MDO process, 3) Non-sensitive gauges reducing, and 4) Slightly optimization. Considering the mixed variables in the MDO process including continuous geometry shapes and discrete gauges, the developed continuous relaxation method was employed to deal with such situation. A real application of BIW design was implemented to illustrate the efficiency and contribution of such proposed optimization process. The attributes considered during optimization include global bend and torsion modal/stiffness. The MDO and non-sensitive gauge reducing processes are implemented to lead to a significant weight saving over 7.5 kg. Copyright © 2016 SAE International.

Wen Y.,Changan Automobile Engineering Institute | Wang Y.,Afton Chemical Corporation | Fu C.,Changan Automobile Engineering Institute | Deng W.,Changan Automobile Engineering Institute | And 5 more authors.
SAE Technical Papers | Year: 2016

Gasoline Direct Injection (GDI) engines have developed rapidly in recent years driven by fuel efficiency and consumption requirements, but face challenges such as injector deposits and particulate emissions compared to Port Fuel Injection (PFI) engines. While the mechanisms of GDI injector deposits formation and that of particulate emissions have been respectively revealed well, the impact of GDI injector deposits and their relation to particulate emissions have not yet been understood very well through systematic approach to investigate vehicle emissions together with injector spray analysis. In this paper, an experimental study was conducted on a GDI vehicle produced by a Chinese Original Equipment Manufacturer (OEM) and an optical spray test bench to determine the impact of injector deposits on spray and particulate emissions. The vehicle, with the mileage over 13,000 km, was subject to emissions tests such as gaseous emissions, particulate mass (PM), and fuel economy on a chassis dynamometer under the new European driving cycle (NEDC), then re-tested after having its injectors replaced. Deposit morphology and spray characteristic experiments including spray angle, penetration, droplet diameter and velocity distribution as well as near-field spray imaging were also conducted for the coked injectors both before and after cleaning. The results demonstrated GDI injectors were prone to form deposits which resulted in smaller spray angles, longer penetration, smaller droplet diameter, and higher velocity as well as severe leakage found at the end of injection. These results can well explain why injector deposits resulted in much higher particulate emissions (increased 376%) as well as higher fuel consumption (3%) after just 13,000km of mileage accumulation. Copyright © 2016 SAE International.

Yang W.,Chongqing University | Zheng L.,Chongqing University | Li Y.,Chongqing University | Ren Y.,Chongqing University | Li Y.,Changan Automobile Engineering Institute
SAE Technical Papers | Year: 2017

This paper proposed a two-section trajectory planning algorithm. In this trajectory planning, sigmoid function is adopted to fit two tangent arcs to meet limited parking spaces by reducing the radius of turning. Then the transverse preview model is established and the path tracking errors including distance error and angle error are estimated. The weight coefficient is considered to distribute the impact factor of traverse distance error or traverse angle error in the total error. The fuzzy controller is designed to track the two-section trajectory in autonomous intelligent parking system. The fuzzy controller is developed due to its real-time and robustness in the parking process. Traverse errors and its first-order derivative are selected as input variables and the outer wheel steering angle is selected as the output variable in fuzzy controller. They are also divided into seven fuzzy sets. Finally, forty rules are decided to achieve effective trajectory tracking. The detailed description of the proposed trajectory planning is demonstrated. The design aspects of Fuzzy Logic Controller and kinematic/dynamic theories in intelligent parking system are investigated in details. A combination of PreScan and Matlab Simulink is used to develop a numerical simulation model in order to verify the effectiveness of the proposed trajectory planning algorithm and Fuzzy Logic Controller in parking system. A superior performance is demonstrated and concluded for the proposed autonomous intelligent parking system. Copyright © 2017 SAE International.

Peng L.,Changan Automobile Engineering Institute | Wang Z.,Changan Automobile Engineering Institute | Su Y.,Changan Automobile Engineering Institute | Li X.,Changan Automobile Engineering Institute | Zhang J.,Changan Automobile Engineering Institute
SAE Technical Papers | Year: 2017

Production variation analysis of vehicle NVH performance becomes more and more necessary in development process. In order to accurately evaluate vehicle NVH responses, this paper presents a general framework involving excitation evaluation, vehicle FE model and results post-processing. Through mind map and parameter diagram analysis of idling shake, the major cause was found to be piece to piece of its powertrain rubber mounts system. Along with the vehicle NVH simulation, a novel decoupled robust-based optimization strategy called SRBF-RBO is applied to PTMS robust optimization. SRBF-RBO distinguishingly features two-steps searching strategy, the "shifting" performance and "tightening" distribution. Based on the adaptive metamodeling technique of SRBF strategy, the "shifting" operation can quickly search deterministic optimum, and improves the approximation accuracy of metamodels around the optimum in local region. With the developed criterion of robustness evaluation, the purpose of the "tightening" step is to minimize the robustness objective in the local space based on SRBF models. Applied to practical PTMS robust design problem, the proposed methodology demonstrates its capability of searching optimal and robust solution. Copyright © 2017 SAE International.

Chen S.M.,Jilin University | Wang D.F.,Jilin University | Zan J.M.,Changan Automobile Engineering Institute
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | Year: 2012

In order to understand the brake judder of a passenger car, the brake judder test of a passenger car was performed with initial speeds of 90, 120, and 150 km/h, end speed of 20 km/h, and pedal forces of 25, 30, 35, and 40 N on a roller dynamometer in a semi-anechoic chamber. The pressure fluctuation of the brake fluid pipe was presented. The accelerations of the steering wheel were recorded at vertical, lateral, and radial directions respectively, and the frequency analysis of the brake judder was also performed. The frequency response functions of the steering system were measured in order to understand the cause of the brake judder. Meanwhile, the multibody system dynamics model of the test vehicle was created with a flexible body and steering system. The brake torque calculated with the brake fluid pressure of the brake pipe in the brake judder test was exerted on the brake systems. The simulated accelerations of the steering wheel were calculated at three different directions, and the frequency analysis of the brake judder was also presented. The design of experiment was presented in order to reduce the brake judder and improve the comfort of the vehicle. An orthogonal array table was designed with 13 factors and 3 levels. The optimum combination was confirmed. The brake judder was also simulated, and the accelerations of the steering wheel were also calculated. Furthermore, the optimization results were verified by the brake judder test. The verification of the optimization indicates that the optimization results are correct and effective. © IMechE 2012.

Chen S.,Jilin University | Wang D.,Jilin University | Liu B.,Changan Automobile Engineering Institute
Fluctuation and Noise Letters | Year: 2013

This paper investigates optimization design of the thickness of the sound package performed on a passenger automobile. The major characteristics indexes for performance selected to evaluate the processes are the SPL of the exterior noise and the weight of the sound package, and the corresponding parameters of the sound package are the thickness of the glass wool with aluminum foil for the first layer, the thickness of the glass fiber for the second layer, and the thickness of the PE foam for the third layer. In this paper, the process is fundamentally with multiple performances, thus, the grey relational analysis that utilizes grey relational grade as performance index is especially employed to determine the optimal combination of the thickness of the different layers for the designed sound package. Additionally, in order to evaluate the weighting values corresponding to various performance characteristics, the principal component analysis is used to show their relative importance properly and objectively. The results of the confirmation experiments uncover that grey relational analysis coupled with principal analysis methods can successfully be applied to find the optimal combination of the thickness for each layer of the sound package material. Therefore, the presented method can be an effective tool to improve the vehicle exterior noise and lower the weight of the sound package. In addition, it will also be helpful for other applications in the automotive industry, such as the First Automobile Works in China, Changan Automobile in China, etc. © 2013 World Scientific Publishing Company.

Chen S.-M.,Jilin University | Wang D.-F.,Jilin University | Cao X.-L.,Jilin University | Zan J.-M.,Changan Automobile Engineering Institute
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2010

The basic reciprocity relation for a random component was demonstrated, the reciprocity relation for a random component was introduced through the wave approach and the modal approach. The coupling between two area junction subsystems was also introduced. The hybrid FE-SEA equation was given at the last demonstration for the theoretic results. Hybrid FE-SEA model of the car was built, the radiation efficiencies of the body panels of the car were calculated, and the excitations of the powertrain mounts and body suspensions of the car were measured. The acoustic excitation of the engine cabin was measured in anechoic room. And CFD wind tunnel was built to compute the wind excitations. Meanwhile, the car interior noise was predicted by the hybrid FE-SEA model subjected to all of excitations. Furthermore, the prediction result of the car interior noise was verified by the experimentation, and the reasons of the error were analyzed. The analysis result shows that the absolute error is less than 2.5 dB (A), the prediction precision is satisfied with engineering requirement, and the method of FE-SEA modeling is effective to predict middle frequency noise within the car interior.

Zheng W.,Huazhong University of Science and Technology | Zheng W.,State Key Laboratory of Vehicle NVH and Safety Technology | Lei Y.,State Key Laboratory of Vehicle NVH and Safety Technology | Lei Y.,Changan Automobile Engineering Institute | And 3 more authors.
Shock and Vibration | Year: 2013

The potential of using topology optimization as a tool to optimize the passive constrained layer damping (PCLD) layouts with partial coverage on flat plates is investigated. The objective function is defined as a combination of several modal loss factors solved by finite element-modal strain energy (FE-MSE) method. An interface finite element is introduced to modeling the viscoelastic core of PCLD patch to save the computational space and time in the optimization procedure. Solid isotropic material with penalization (SIMP) method is used as the material interpolation scheme and the parameters are well selected to avoid local pseudo modes. Then, the method of moving asymptote (MMA) is employed as an optimizer to search the optimal topologies of PCLD patch on plates. Applications of two flat plates with different shapes have been applied to demonstrate the validation of the proposed approach. The results show that the objective function is in a steady convergence process and the damping effect of the plates can be enhanced by the optimized PCLD layouts. © 2013 - IOS Press and the authors. All rights reserved.

Chen C.,Chongqing University | Zhan Z.,Chongqing University | Li J.,Changan Automobile Engineering Institute | Jiang Y.,Changan Automobile Engineering Institute | Yu H.,Changan Automobile Engineering Institute
SAE Technical Papers | Year: 2016

To reduce the computational time of the iterations in robust design, meta-models are frequently utilized to approximate time-consuming computer aided engineering models. However, the bias of meta-model uncertainty largely affects the robustness of the prediction results, this uncertainty need to be addressed before design optimization. In this paper, an efficient uncertainty quantification method considering both model and parameter uncertainties is proposed. Firstly, the uncertainty of parameters are characterized by statistical distributions. The Bayesian inference is then performed to improve the predictive capabilities of the surrogate models, meanwhile, the model uncertainty can also be quantified in the form of variance. Monte Carlo sampling is finally utilized to quantify the compound uncertainties of model and parameter. Furthermore, the proposed uncertainty quantification method is used for robust design. A numerical example and a real-world vehicle lightweight case study are used to demonstrate the validity of the proposed method. Copyright © 2016 SAE International.

Xia Y.F.,Changan Automobile Engineering Institute | Pang J.,Changan Automobile Engineering Institute | Hu C.,Changan Automobile Engineering Institute | Zhou C.,Changan Automobile Engineering Institute | Wu C.,Changan Automobile Engineering Institute
SAE Technical Papers | Year: 2014

The paper analyzes the characteristics of driveline torsional vibration of a RWD vehicle and provides the control methods of transmission rattle noise caused by the system torsional resonances. A driveline dynamic model of the RWD vehicle is established by multi-body dynamic method. The natural frequencies and modal shapes are calculated for each gear position and torsional vibration responses are predicted by forced vibration analysis. The system sensitivity and DOE are analyzed based on the parameterized stiffness, inertia and damping. The 2nd and 3rd order modal results show that the transmission shaft possesses the maximum amplitudes and its corresponding modal frequencies vary with different gear position. The sensitivity analysis results show that the system torsional vibration is significantly reduced by reducing clutch stiffness, increasing propeller shaft stiffness, raising half shaft stiffness, increasing the input shaft inertia and increasing the clutch damping. The DOE analysis results show that the clutch stiffness, propeller shaft stiffness, and the inertia of axle pinion shaft and transmission input shaft play an important role in reducing torsional vibration of the transmission gear shafts. A clutch with small stiffness and large torsional angle is tested and the transmission gear rattle noise is greatly reduced. The analysis results show excellent consistency with the test results. Copyright © 2014 SAE International.

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