Refine Your Search

Topic

Author

Search Results

Technical Paper

Development of the Wireless Power Transfer Technology for a Sliding Door

2019-04-02
2019-01-0485
The sliding door’s movement is 3-dimensional unlike the conventional door. So the electric power and signal are exchanged via the long ‘Power Cable’. It has a quite complex structure in order to be suitable to connect the vehicle’s body and the sliding door even during it’s moving. As the result, it is more expensive than conventional door’s one and the quality could not be guaranteed easily. In this paper, I have developed new technology which could transfer electric power by ‘wireless transfer’ in order to resolve the problem from using ‘Power cable’. I would propose the proper structure to transfer the electric power at any position of the sliding door without any physical connection. To transfer the electric power which drives the window regulator and the actuators in door, I have applied the ‘inductive coupling’ system.
Technical Paper

Incorporation of Friction Material Surface Inhomogeneity in Complex Eigenvalue Analysis to Improve the Accuracy of Brake Squeal Analysis

2018-10-05
2018-01-1873
The sliding surface of the brake friction material is not uniform but composed of random contact plateaus with a broad pressure distribution, which are known to closely related to the triggering mechanism of friction induced noise and vibrations. The non-uniform contact plateaus are attributed to the various ingredients in the friction material with a broad range of physical properties and morphology and the size and stiffness of the plateau play crucial roles in determining the friction instability. The incorporation of friction surface inhomogeneity is, therefore, crucial and has to be counted to improve the accuracy of the numerical calculation to simulate brake noise. In this study, the heterogeneous nature of the friction material surface was employed in the simulation to improve the correlation between numerical simulations and experimental results.
Technical Paper

Optimization of Slot Disc Shape for Improving Brake Fade Performance

2018-10-05
2018-01-1883
Due to improvements in vehicle powertrain performance, friction material fade performance is becoming an important topic. For this reason, needs for studies to improve thermal characteristics of the brake system is increasing. Methods for improving the fade characteristics have several ways to improve the thermal characteristic of friction materials and increase disc capacity. However, increasing disc capacity(size) have some risk of weight and cost rise, and friction factor improvements in friction material tend to cause other problems, such as increasing squeal wire brush noise and increasing metal pick up on disc surface. Therefore, a slot disc study is needed to overcome the problems discussed previously. Currently, there is few research history for slot disc related to fade and metal pickup improvements.
Technical Paper

An Application of Acoustic Metamaterial for Reducing Noise Transfer through Car Body Panels

2018-06-13
2018-01-1566
This paper presents the design of an additional structure based on acoustic metamaterial (AMM) for the reduction of vibro-acoustic transfer function of a car body panel. As vehicles are lighter and those engine forces are bigger recently, it has become more difficult to reduce the vibration and noise transfer through body panels by using just conventional NVH countermeasures. In this research, a new approach based on AMM is tried to reduce the vibration and noise transfer of a firewall panel. First, a unit cell structure based on the locally resonant metamaterial is devised and the unit cell’s design variables are studied to increase the wave attenuation in the stop band of a dispersion curve, where the Floquet-Bloch theorem is used to estimate the dispersion curve of a two-dimensional periodic structure. Also, the vibration transfer and the vibro-acoustic transfer are predicted in a FE model of meta-plate which is composed of a periodic system of the devised unit cell.
Technical Paper

Research on Stick & Sprag-Slip Phenomenon of Door Waist Belts

2018-04-03
2018-01-0674
The squeak noise generated during the moving of the door glass has a influence on the performance of vehicles felt by the consumer. In order to improve the noise, it is necessary to understand the principle of a friction vibration. In this paper, it is confirmed that the principle on the waist belt is most closely related to stick-slip and sprag-slip among various vibration characteristics. Stick-slip is expressed by energy accumulation and divergence due to difference in static and dynamic friction coefficient. Sprag-slip define instability of geometric structure due to angle of lips on the belt. In this paper, the physical model and the energy equation are established for the above two phenomena. Stick-slip can be solved by decreasing the difference of the static and dynamic friction coefficient. Sprag-slip is caused by the ratio of compressive and shear stiffness of the lips. The belt uses flocking to ensure durability, not coating.
Technical Paper

Analysis of Rear Brake Grinding Noise by Rear Suspension Types

2017-09-17
2017-01-2486
Brake grinding noise is caused by the friction of the disc and pads. The friction generates vibration and it transmits to the body via the chassis system. We called it structure-borne noise. To improve the noise in the vehicle development, the aspects of chassis or body's countermeasure occurs many problems, cost and time. In this reason many brake companies try to make solution with brake system, like brake pad materials or disc surface condition. However the countermeasures of excitation systems also have a lot of risk. It could be occurred side-effects of braking performance, and need to re-verify brake noise like Creep-groan, Groan, Squeal, Judder and so on. For this reason, it is essential to make a robust chassis system in the initial development stage of the vehicle for the most desirable grinding noise-resistant vehicle. This paper is about rear brake grind noise path analysis and countermeasure of chassis system. There are two steps to analysis.
Technical Paper

Analysis of Vehicle Voice Recognition Performance in Response to Background Noise and Gender Based Frequency

2017-06-05
2017-01-1888
Voice Recognition (VR) systems have become an integral part of the infotainment systems in the current automotive industry. However, its recognition rate is impacted by external factors such as vehicle cabin noise, road noise, and internal factors which are a function of the voice engine in the system itself. This paper analyzes the VR performance under the effect of two external factors, vehicle cabin noise and the speakers’ speech patterns based on gender. It also compares performance of mid-level sedans from different manufacturers.
Journal Article

A Novel Method for Objective Evaluation of Interior Sound in a Passenger Car and Its Application to the Design of Interior Sound in a Luxury Passenger Car

2017-06-05
2017-01-1758
Recently the interior sound is actively generated by the active sound design (ASD) device in a passenger car. Therefore, the objective evaluation method for the sound quality of actively designed sounds is required. In previous research, the sound quality of interior sound has been presented with powerful and pleasant for the existing passenger car. This paper presents a novel approach method for the objective evaluation of powerfulness and pleasantness of actively designed interior sound. The powerfulness has been evaluated based on the degreed of modulation and a quantity of low frequency booming of the sound in the paper. On the other hand, the pleasantness is evaluated based on the slope ratio of harmonic orders per octave in frequency domain. These evaluation methods are successfully applied to the objective evaluation of luxury passenger car.
Technical Paper

A Case Study: Application of Analytical and Numerical Techniques to Squeak and Rattle Analysis of a Door Assembly

2015-06-15
2015-01-2257
Squeak and rattle (S&R) problems in body structure and trim parts have become serious issues for automakers because of their influence on the initial quality perception of consumers. In this study, various CAE and experimental methods developed by Hyundai Motors for squeak and rattle analysis of door systems are reported. Friction-induced vibration and noise generation mechanisms of a door system are studied by an intelligent combination of experimental and numerical methods. It is shown that the effect of degradation of plastics used in door trims can be estimated by a numerical model using the properties obtained experimentally. Effects of changes in material properties such as Young's modulus and loss factor due to the material degradation as well as statistical variations are predicted for several door system configurations. As a new concept, the rattle and squeak index is proposed, which can be used to guide the design.
Technical Paper

Development of an Algorithm to Automatically Detect and Distinguish Squeak and Rattle Noises

2015-06-15
2015-01-2258
Squeak and rattle (S&R) noises are undesirable noises caused by friction-induced vibration or impact between surfaces. While several computer programs have been developed to automatically detect and rate S&R events over the years, no reported work has been found that can detect squeak and rattle noises and distinguish them. Because the causes of squeak noises and rattle noises are different, knowing if it is a squeak noise or rattle noise will be very helpful for automotive engineers to choose an appropriate measure to solve the problem. The authors have developed a new algorithm to differentiate squeak noises and rattle noises, and added it to the S&R detection algorithm they had developed previously. The new algorithm utilizes a combination of sound quality metrics, specifically sharpness, roughness, and fluctuation strength.
Technical Paper

Study of Reduction Method of Brake Grind Noise

2014-09-28
2014-01-2513
Rust accumulated on disc surfaces causes brake judder and grind noise. This paper deals with grind noise(wire brush brake noise) in vehicles which is a low frequency vibration and broadband noise problem at 100∼1kHz that appears in low vehicle speed. Recently, the customer complaints have increased for grind and creep groan noise more than squeal noise. Low frequency brake noise is a combined effect of brake and suspension systems working with each other. The noise transfer path is also important. Experimental results are confirmed through ODS, Modal, TPA and 3D acoustic camera for noise transmission path. Finally, reduction methods of grind noise are presented.
Technical Paper

A Study on the Transfer Path Analysis of Brake Creep Groan Noise

2014-09-28
2014-01-2510
Creep groan noise occurs in a just moving vehicle by the simultaneous application of torque to the wheel and the gradual release of brake pressure in-vehicle. It is the low frequency noise giving the driver a very uncomfortable feeling. It is caused by the stick-sleep phenomenon at the lining and disc interface. Recently, the field claim of low frequency creep groan has increased. There are a lot of efforts to improve creep groan noise by means of modification of lining material. In this paper, Transfer path of creep groan noise was analyzed through ODS and TPA. Additionally the correlation between Source (Brake torque variation, Brake vibration) and Creep Groan Sound level was discussed. Finally countermeasure to Creep Groan noise was suggested.
Technical Paper

An Improved Methodology for Calculation of the Inertial Resistance of Automotive Latching Systems

2014-04-01
2014-01-0544
This paper outlines an improved methodology to perform calculations to verify the compliance of automotive door latch systems to minimum legal requirements as well as to perform additional due diligence calculations necessary to comprehend special cases such as roll over crashes and locally high inertial loadings. This methodology builds on the calculation method recommended by SAE J839 and provides a robust and clear approach for application of this method to cable release systems, which were not prevalent at the time J839 was originally drafted. This method is useful in and of itself but its utility is further increased by the application of the method to a Computer Aided Design (CAD) template (in this case for Catia V5), that allows some automation of the calculation process for a given latch type. This will result in a savings of time, fewer errors and allows for an iterative concurrent analysis during the design process.
Technical Paper

Two-Step Hood Opening System Development for Easier Hood Opening Operation

2014-04-01
2014-01-0363
Recently, the demand for improving the merchantability of hood open system has been increasing. A novel concept hood open system was proposed by Hyundai Motor Company (HMC) in 2012, which was based on a two-step open latch mechanism. The new hood opening mechanism satisfies Safety laws and improves merchantability.
Technical Paper

Evaluation System for Simulating and Reducing Interior Noise Caused by Wind

2014-04-01
2014-01-0038
Fluctuation in the sound pressure level of the interior noise of an on-road vehicle is always caused by unpredictable factors such as wind gusts, traffic, roadside obstacles, and changing drive-by-drive conditions, and is hence, not reproducible in nature. Since the human brain is known to be more sensitive to noise that is amplitude-modulated than noise at a steady level [1], it is important to evaluate and improve the NVH performance of a vehicle in terms of the fluctuating interior noise likely to be experienced by drivers or users. To this end, an evaluation system was developed as part of this study, the details of which are presented in this paper. The system is composed of hardware for database storage and replay of sounds, and software for synthesizing the noise signals. For given wind tunnel test results, the evaluation system yields a wind noise model that can synthesize wind noise signals for any wind scenario.
Technical Paper

A Study on the Strategy and Implementing Technology for the Development of Luxurious Driving Sound

2014-04-01
2014-01-0035
This paper describes a systematic approach to the development of a luxurious driving sound. In the first step, the luxurious sound is conceptualized through jury test, factor analysis and regression analysis. From the results, the main factors and the correlation equation for the luxurious sound are extracted. Also, customer's preference for the luxurious sound is investigated from the customer clinic. In the second step, three core axes and the detailed indices for luxurious sound are defined and quantified. These core axes are a dynamic sound character, a sound balance and a sound harmony. These core axes are also composed of detailed indices and quantified by guide lines. In the third step, each contribution of the sub-systems for sound quality is identified and the target values and methods for implementing the luxurious sound are suggested. In this process, noise path analysis and the customer's preference in each region are considered.
Technical Paper

Muffler Sound Development Using Analysis of Acoustic Source of Engine Exhaust System

2014-04-01
2014-01-0026
In order to achieve the proper automobile interior sound, the tailpipe noise of the exhaust system must be considered as a main contributor. This paper describes a study of the achievement of dynamic sound quality through exhaust system design. Firstly, we determined the vehicle's interior sound quality and established a target sound using a subjective assessment of 10 benchmark vehicles. The exhaust noise target is determined by means of transfer path analysis focusing on the noise source and how it's impacted by the muffler design. The exhaust system is commonly modeled as a combination of source strength and impedance. We obtained the source character by the wave decomposition method using two microphones and six loads ultimately leading to an optimized design of the inner muffler structure. Based on this study, we achieved dynamic interior sound and improved exhaust system performance.
Technical Paper

Optimization of Body Structure for Road Noise Performance

2014-04-01
2014-01-0010
It is common knowledge that body structure is an important factor of road noise performance. Thus, a high stiffness of body system is required, and determining their optimized stiffness and structure is necessary. Therefore, a method for improving body stiffness and validating the relationship between stiffness and road noise through CAE and experimental trials was tested. Furthermore, a guideline for optimizing body structure for road noise performance was suggested.
Technical Paper

Material NVH Convergence Technology for a Plastic Intercooler Pipe

2014-04-01
2014-01-1040
The main contribution of this paper is to employ a sound and vibration theory in order to develop a light and cost effective plastic intercooler pipe. The intercooler pipe was composed of two rubber hoses and one aluminum pipe mounted between an ACV (Air Control Valve) and an intercooler outlet. The engineering design concept is to incorporate low-vibration type bellows and an impedance-mismatched center pipe, which replaces the rubber hoses and aluminum pipe respectively. The bellows were designed to adapt powertrain movement for high vibration transmission loss to the intercooler outlet. Also, the impedance-mismatched center pipe was implemented to increase reflected wave by using relatively higher modulus than bellows part and applying a SeCo (Sequential Coextrusion) processing method.
Technical Paper

Design for NVH Performance and Weight Reduction in Plastic Timing Chain Cover Application

2014-04-01
2014-01-1043
Light weighting is a critical objective in the automotive industry to improve fuel efficiency. But when redesigning parts for light weight, by changing from metal to plastic, the resulting design gives NVH issues due to differences in part mass and material stiffness. Many parts were not converted from metal to plastic because of NVH issues that could not be solved. Many engine parts such as cylinder head cover, air intake manifold, oil pan and etc. previously made of metal have since long been replaced with plastic. But timing chain cover has not been replaced because of the aforementioned issue. Sealing performance due to the dynamic characteristics of the application is another challenging factor. In this paper, the key aspects of the plastic timing chain cover as well as its advantage are presented.
X