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As environmental concerns have taken the spotlight, electrified powertrains are rapidly being integrated into vehicles across various brands, boosting their market share. With the increasing adoption of electric vehicles, market demands are growing, and competition is intensifying. This trend has led to stricter standards for noise and vibration as well. To meet these requirements, it is necessary to not only address the inherent noise and vibration sources in electric powertrains, primarily from motors and gearboxes, but also to analyze the impact of the spline power transmission structure on system vibration and noise. Especially crucial is the consideration of manufacturing discrepancies, such as pitch errors in splines, which various studies have highlighted as contributors to noise and vibration in electric powertrains. This paper focuses on comparing and analyzing the influence of spline pitch errors on two layout configurations of motor and gearbox spline coupling structures.

The development trend of new vehicles is to shorten the development period, diversify the models, and produce small amounts compared to the past. The current development process of braking systems is difficult to meet recent development trends, and it is more difficult to shorten the development period in the verification process that requires actual products. In this paper, we developed a 1-D Simulation of AMESim, MATLAB/Simulink Co-Simulation model of Hyundai Mobis iMEB(Integrated Mobis Electronic Brake) system for eco-friendly vehicles. If hydraulic braking is applied more than the tire grip force during braking, tire slip occurs, and if the rear wheel is locked before the front wheel, stability is lost, so it is advantageous to decide design parameter of brake system to make the front wheel first locked in consideration of design parameters of each vehicle.

The automotive industry’s journey towards fully autonomous vehicles brings more and more vehicle control systems. Additionally, the reliability and robustness of all these systems must be guaranteed for all road and weather conditions before release into the market. However, the ever-increasing number of such control systems, in combination with the number of road and weather conditions, makes it unfeasible to test all scenarios in real life. Thus, the performance and robustness of these systems needs to be proven virtually, via vehicle simulations. The key challenge for performing such a range of simulations is that the tire performance is significantly affected by the road/weather conditions. An end user must therefore have access to the corresponding tire models. The current solution is to test tires under all road surfaces and operating conditions and then derive a set of model parameters from measurements.

Recently, keen interest has been focused on the reduction of fuel consumption through the development of eco-friendly and weight-effective vehicles. This is due in part to the strengthening of regulatory standards for fuel efficiency in each country. This study will focus on the optimization of the IP (Instrument Panel) module, in particular, the cowl crossbar, which in some vehicles, can account for more than 33% of the IP module weight. The design objectives of the cowl crossbar were to use continuous fiber thermoplastic composite materials to achieve high stiffness, while optimizing the strength to weight performance as evaluated through vehicle sled and crash testing. This research will introduce the development and optimization methodology for an alternative material, which achieved about a 30% weight reduction as compared to steel.

Owing to an increasing autonomous emergency braking (AEB) adoption, emergency braking before crash occurs more often than in the case of conventional vehicles. Due to the sudden deceleration in AEB activation, passengers move forward before the crash. To explore how this forward movement affects passenger injury, sled tests are performed with an inclined dummy representing forward displacement. The test shows that a shorter distance between the airbag and passenger results in bigger neck injuries induced by airbag deployment force. A countermeasure is suggested to prevent neck injury in emergency braking situation by reducing deployment force and protrusion.

Requirements of side curtain airbag have continued to increase. The revised SINCAP, FMVSS-226 ejection mitigation and small overlap of IIHS had added these requirements. To meet all the requirements, high inflator energy and complex cushion shape became necessary. Such situations increased possibility of cushion failure while deploying. Unfortunately, all the design verification tests are usually completed in a relatively latter stage of development and repetitive testing is needed to consider large dispersion of failure probability distribution. Therefore, verification and design improvement by numerical simulation in an early stage are desirable. A simulation method which can verify CAB deployment was developed in this study. The developed method has three distinct features. Firstly, nonlinear fabric materials and membrane finite elements are used to consider fracture of cushion fabric. Secondly, a pre-simulation procedure had been established.

The role of CAB is protecting the passenger's head during rollover and side crash accidents. However, the performance of HIC and ejection mitigation has trade-off relation, so analytical method to satisfy the HIC and ejection mitigation performance are required. In this study, 3 types of CAB were used for ejection mitigation analysis, drop tower analysis and SINCAP MDB analysis. Impactor which has 18kg mass is impacting the CAB as 20KPH velocity at six impact positions for ejection mitigation analysis. In drop tower analysis, impactor which has 9kg mass is impacting the CAB as 17.7KPH velocity. Acceleration value was derived by drop tower analysis and the tendency of HIC was estimated. Motion data of a vehicle structure was inserted to substructure model and the SID-IIS 5%ile female dummy was used for SINCAP MDB analysis. As a result, HIC and acceleration values were derived by MDB analysis.

Electric vehicles are considered not only eco-friendly but also quieter than vehicles with conventional internal combustion engines. However, less noisy environments in cabins make passengers feel uncomfortable to moderate noise. This paper discusses noise reduction for electric vehicles radiated from traction motors. In the analysis of the noise generation mechanisms it is demonstrated that frequency ranges of the highest level in the noise spectrum of electromagnetic harmonic orders of the induction motor coincide with structural resonances of the motor housing. Interfacial friction between the inner and outer housings of the motor is employed in reducing structural vibration of the motor. Measured noise in the cabin and vibration at the motor housing indicates that slip damping presented from interfacial friction between the inner and outer housing is effective in reducing noise from the traction motor and in the cabin.

This paper proposes a simplified method to make the flux table considering the magnetic flux variation of the IPMSM (Interior Permanent Magnet Synchronous Machine) caused by temperature change in vehicle traction applications. Nowadays, normally an IPMSM with a rare-earth magnet is used for HEV traction applications. But because the flux density of the magnet varies with temperature, the optimal operating points, such as MTPA (Maximum Torque Per Ampere) and MTPV (Maximum Torque Per Voltage) of the motor drift according to temperature change. Those operating points can be expressed in a lookup table, that is, a flux table obtained by off-line experiment, which produces the DQ-axis current command with respect to the torque and flux reference. To reflect this temperature dependence in control, usually flux tables are generated at high, medium and low temperatures. Conventionally, all the three tables are constructed by experiment, which takes a great deal of time.

Since the environmental problems and new stricter regulations are forcing the industries to introduce more ecological materials for their products, biodegradable materials have attracted increasing attention. Among these materials, Polylactic acid (PLA) is remarkable for its modulus, strength, chemical resistance. However, PLA could not be used for automobile industries for its low heat resistance and impact strength. Therefore, in this study natural fiber was introduced as reinforcements in order to improve the properties of PLA. And for various experiments, Polypropylene (PP) was used as matrix resin instead of PLA. Especially for improving the properties of PLA composites, surface treatments, annealing, and adding rubber elements were performed. With surface treatments, we found that the mechanical properties of composite were improved. And with annealing treatment, we found the remarkable increase of heat resistance of PLA composite.

This paper describes a lateral disturbance estimator for an application to a Motor Driven Power Steering (MDPS)-based driving assistant system. A vehicle motion can be disturbed laterally by wind force or load from bank angle acting on the vehicle in the lateral direction. An MDPS-based driving assistant system can be used to reduce steering effort of a human driver in a driving situation with lateral disturbance. In designing the MDPS-based driving assistant system, the lateral wind disturbance should be estimated to determine an assistant torque. An estimator for the vehicle lateral disturbance estimation has been developed. The proposed estimator consists of two parts: a tire self-aligning torque estimator and the lateral disturbance estimator. The lateral disturbance estimator has been designed on the basis of a 2-DOF bicycle model with available sensor signals from the MDPS module. A numerical simulation has been conducted in order to evaluate the proposed estimator.

In recent years, products that make use of integrated safety that use the environmental data to optimize occupant restraints have been on the market. Pre-safe system in the integrated safety category is an adaptive and smart protection system that utilizes the occupant information and the monitoring information on the accident prediction. These pre-safe systems need the proper algorithm corresponding to the crash scenario for the crash unavoidable state. Due to the crash scenario categories for the real world accidents is quite various, the development of the algorithm and the occupant protection system to reduce the injury is quite complex and costly. For this reason, a development process for pre-safe related integrated safety systems demands new tools based on the biomechanics to help design and assessment. The virtual development and assessment process with a viewpoint on the efficiency of the restraint development has been developed.

The main role of CAB(side curtain airbag) is to protect the occupant's head in the event of side crash. The updated US NCAP for model year 2010 requires more extended coverage of CAB. It is not only required to cover the 50th%ile driver but also the 5th%ile driver and rear passenger. Although the general safety analysis model using only concerned sub-structure of the vehicle and prescribed structural motion is sufficient to handle frequent jobs, the analysis model with increased efficiency is needed when optimization is to be studied as it requires more runs and the model gets enlarged to consider extended sub-structure. In this study, three types of simplified analysis models are introduced. The first has an impactor which is composed of the head and neck with prescribed translational motions. It only uses the upper parts of the original sub-structure hence the run time is saved by 60∼70%.

Gas leakage properties in numerical models of a SAB (Side Air Bag) need to be estimated without any component testing for a prompt simulation. A reasonable and accurate method for predicting leakage properties, which can be used in MADYMO simulations, is introduced in this study. Leakage functions were formulated with 9 assumptions and coefficients of functions are obtained based on information about components of SABs. The Information and the obtained coefficients were collected as a database. 29 types of drop tower tests were done to build this database. Four types of SABs were chosen and tested to validate the accuracy of the developed prediction method. The resulting correlations between simulations and tests turned out to be sufficiently accurate.

As occupant injuries induced by airbag deployment became a critical issue, revisions to FMVSS 208 were made to mandate the adoption of advanced airbag which can protect occupants of varying statures. As a result, OCS (Occupant Classification System) has become an important part of advanced airbag technologies. In this paper, we review existing OCS technologies briefly and list details of development issues and solutions for weight-based OCS. As an effort to reduce cost and optimize performance for the semi-LRD (Low Risk Deployment) airbag system, a study on reducing the number of sensors from 4 to 2 for the current system utilizing DFSS methodology is provided and discussed.

The instrument panels are made to meet stiffness requirements and also interior safety regulation such as head impact test. Nowadays, CAE is widely used to predict the test results in advance. However, considering fracture phenomena, the characteristics of material takes a significant role for the simulation of the real tests. In this paper, high speed tensile tests and fracture tests of specimens representing typical stress-states were performed to make a fracture criterion of a plastic material (PC/ABS). The suggested method was validated by comparing simulation with test results.

The paper presents a new offset compensation method of a yaw rate sensor and a lateral acceleration sensor. It is necessary to compensate the offsets of the analog sensors, such as the yaw rate sensor and the lateral acceleration sensor, to acquire accurate signals. This paper proposes two different offset compensation algorithms, the sequential compensation method and the model based compensation method. Both algorithms are combined with the algorithm map depending on the vehicle driving status. The proposed algorithm is verified by the computer simulations.

We performed numerical analyses using an explicit code to evaluate the cumulative impact damage of an automotive front-end bumper during low-speed crash events, as described by CMVSS215. The CMVSS215 regulation consists of a series of test cases for the same parts. To evaluate the crash performance of a bumper, we used a coupled numerical analysis scheme and considered several matters such as the removal of residual vibrations and the evaluation of the bumper back beam recovery. We also used an EWK rupture model in the PAM-CRASH code to improve our damage and fracture estimates. Tensile test experiments were conducted to tune the performance of the EWK rupture model; the resulting material properties and fracture criterion were incorporated into the numerical analyses of the low-speed frontal crash events. The coupled analysis scheme was verified by comparing the output with bumper impact test data.

This paper is intended to find out the optimized restraint system for various crash conditions and to analyze the characteristics of those conditions numerically. 40km/h FF (Full Frontal crash), 56km/h FF and 64km/h ODB (Offset Deformable Barrier crash) conditions have been considered with 5th%ile female, 50th%ile male and 95th%ile male dummies on driver side. The vehicle lay out and crash pulses came from a compact passenger car. The restraint system was focused on the driver side airbag and seat belt. MADYMO 3D was used in this study for simulation.