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The front rail, as one main energy absorption component of vehicle front structures, should present steady progressive collapse along its axis and avoid bending collapse during the front oblique impact, but when the angle of loading direction is larger than some critical angle, it will appear bending collapse causing reduced capability of crash energy absorption. This paper is concerned with crashworthiness design of the front rail on a vehicle chassis frame structure considering uncertain crash directions. The objective is to improve the crash direction adaptability of the front rail, without deteriorating the vehicle's crashworthiness performance. Magic Cube (MQ) approach, a systematic design approach, is conducted to analyze the design problem. By applying Space Decomposition of MQ, an equivalent model of the vehicle chassis frame is generated, which simplifies the design problem.

Super-knock has been a significant obstacle for the development of highly turbocharged (downsized) gasoline engines with spark ignition, due to the catastrophic damage super-knock can cause to the engine. According to previous research by the authors, one combustion process leading to super-knock may be described as hot-spot induced pre-ignition followed by deflagration which can induce detonation from another hot spot followed by high pressure oscillation. The sources of the hot spots which lead to pre-ignition (including oil films, deposits, gas-dynamics, etc.) may occur sporadically, which leads to super-knock occurring randomly at practical engine operating conditions. In this study, a spark plasma was used to induce preignition and the correlation between super-knock combustion and the thermodynamic state of the reactant mixture was investigated in a four-cylinder production gasoline engine.

This presentation evaluates the contribution of multi-objective programming scheme for the conceptual design of the Hybrid Electric Vehicle frame's structure using topological optimization. The compromise programming method was applied to describe the statically loaded multicompliance topology optimization. Solid Isotropic Material with Penalization (SIMP) was used as the interpolation scheme to indicate the dependence of material modulus upon regularized element densities. The sequential convex programming approach was applied to solve the optimization problem. The application on the chassis frame was used to demonstrate the characteristics of the presented methodologies based on the commercial software package OptiStruct.

Ten sets of mesh parameters are considered in building the model for aerodynamic numerical simulation of a CHERY sedan. It is found that, in comparison with the wind tunnel test data, the error in drag coefficient computed by using these meshes is less than 4%. Especially, in one case, the error is found within 1%. The CAE method discussed in this paper can be used to assist the design of vehicle aerodynamics.

The electronic control system of the variable nozzle turbocharger (VNT) was designed. The actuator is the electro-hydraulic servo proportional solenoid. The signals of the engine pedal position sensor, the engine speed sensor, the boost pressure sensor, the intake air temperature sensor, and the ambient pressure sensor are sampled and filtered. The engine working condition is estimated. The control algorithm was designed as the closed-loop feedback digital PI control together with the open-loop feed forward control. The gain-scheduled PI control method is applied to improve the robustness. The control system was calibrated at the turbocharger test bench and the engine test bench. The results indicate the designed control system has good performance for the boost pressure control under the steady and transient conditions.

Rubber bushing is an important connection component in vehicle suspensions. It plays an important role in vehicle performance. In the past years, the theories of rubber have been studied, and several forms of the strain energy potential, incompressible or almost incompressible, have been developed. But not all of these models are suitable for all kinds of applications. Therefore, when investigating the rubber bushing, it is necessary to find the effective constitutive equations. Two bushings with different shapes are studied. One is an ax-symmetric uniform bushing. The other one has additional two longitudinal holes. A process of parameter identification is conducted. The axial stiffness and radial stiffness of the bushing are tested and used as objectives. The parameters of constitutive equations are defined as design variables. The nonlinear analysis software ABAQUS and a multi-disciplinary optimization software OPTIMUS are used.

The understeer of vehicle is desired for the vehicle's handling performance, and the roll rate of rear suspension is one of the key characteristics to achieve the understeer performance. A proper roll rate of the rear suspension is required to assure a certain level of understeer. Generally, in the vehicle dynamic tuning process, several methods are available for improving understeer performance, e.g., changing the hard-points of suspensions, adjusting stiffness of bushings, etc. On the other hand, structure optimization of components can be used in some case to improve the performance. In this paper, the optimization method is applied to the twist beam of rear suspension. The change in local geometry by optimized design leads to appropriate adjustment of the roll rate. Finally the vehicle understeer performance reaches design target.

Stiffness is one of the key points for research and development of vehicle body in white (BIW). Fast and effective evaluation of stiffness is very important for reducing the time and cost of research and development. How to realize weight reduction with proper stiffness is also a focus point of automobile design. In general, commercial software is used to optimize the BIW design. But the optimization process is time consuming. Therefore a simple but effective tool for fast evaluation is desired. A method to evaluate stiffness with sensitivity coefficients of sheet metal thickness of body structure is proposed in this paper. The simple mathematical relation of the sensitivity coefficients, the thickness variation of sheet metals, and the stiffness of body structure is established. The stiffness can be evaluated quickly for various combination of sheet metal thickness without running large-scale simulation using commercial software.

The door closing effort is one of the first impressions to customer's mind about the engineering and quality of the vehicle. The door closing force and the minimum door closing speed are two important characteristics for evaluation. But we can obtain these two indices only by experiments and/or subjective assessments. To predict the door closing effort by the simulation method during the design phase, a finite element analysis model is established. The compression load deflection behavior of seals is converted to the parameters of constitutive model of seals by the parameters identification method. Then, the seal resistance force and the minimum door closing speed are calculated. The later correlates very well with the experiment data.

The whiplash disorders are associated with huge costs for society. The BioRID (Biofidelic Rear Impact Dummy) dummy and the test procedure are developed to ensure the seat systems optimized to reduce the risk of injury in low-severity rear-end collisions. This paper discussed the BioRID dummy spine structure and calibration procedures. It is found during the dynamic calibration it is very difficult to keep the head neck OC (Occipital Condyle) joint in the static corridor and different head position will obtain the different score in the EuroNCAP whiplash Seat Assessment. A proposal is developed to control the OC joint in the dynamic calibration to ensure the whiplash test can be conducted correctly.

In this paper, a good example on integration of CAE (Computer Aided Engineering) and RLD (Road Load Data) analysis is introduced. It works well in the process of investigating the hinge crack problem of a vehicle hood and leads to schemes which are suitable to the root cause found. As the byproducts, a design target is confirmed and a procedure of problem investigating is proposed, as shown in Flowchart 1. Flowchart 1 Problem Investigating Procedure In order to ascertain the reason of the crack, multiple methods have been used, such as material verification, manufacturing examination, typical load case evaluation by CAE, and RLD analysis etc. Eventually, the reason is proved to be structural resonance by the common thread of both CAE and RLD. During the progress of problem solving, four main steps are involved and mentioned in the following sections.

The series of work introduced in this paper is originated from a structural failure of the vehicle A/C (Air-Conditioner) pipe, and when many possible factors having been excluded, the main investigating endeavor is focused on RLD acquisition and analysis, which eventually leads to the successful design improvement. During this process, many important signal collectives, such as micro-strains, accelerations, and engine speed are provided by RLD acquisition in some predefined conditions. Subsequently, these signals are analyzed both in time and frequency domain. Furthermore, order analysis by correlation of acceleration and engine speed is also performed to find a definite reason. As a conclusion, the root cause to the crack is not excitation from the road, but mainly from the engine. Based on this conclusion, structure design is improved and is theoretically proved to be effective by the RLD comparison analysis.

The main objective of this paper was to investigate the pressure drop characteristics of ACT (asymmetric cell technology) design filter with various inlet mass flow rates, soot loads and ash loads by utilizing 1-D computational Fluid Dynamics (CFD) method. The model was established by AVL Boost code. Different ratios of inlet to outlet channel width inside the DPF (Diesel Particulate Filter) were investigated to determine the optimal structure in practical applications, as well as the effect of soot and ash interaction on pressure loss. The results proved that pressure drop sensitivity of different inlet/outlet channel width ratios increases with the increased inlet mass flow rate and soot load. The pressure drop increases with the increased channel width ratio at the same mass flow rate. When there is little soot deposits inside DPF, the pressure drop increases with the bigger inlet.

Diesel engines generally tend to produce a very low level of NOx and soot through the application of Miller Cycle, which is mainly due to the low temperature combustion (LTC) atmosphere resulting from the Miller Cycle utilization. A CFD model was established and calibrated against the experimental data for a part load operation at 3000 r/min. A designed set of Miller-LTC combustion modes were analyzed. It is found that a higher boost pressure coupled with EGR can further tap the potential of Miller-LTC cycle, improving and expanding the Miller-LTC operation condition. The simulated results indicated that the variation of Miller timings can decrease the regions of high temperatures and then improve the levels and trade-off relationship of NOx and soot. The in-cylinder peak pressure and NOx emissions were increased dramatically though the problem of insufficient intake charge was resolved by the enhanced intake pressure that is equivalent to dual-stage turbo-charging.