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As automotive technology has been developed, gear whine has become a prominent contributor for cabin noise as the masking has been decreased. Whine is not the loudest source, but it is of high tonal noise which is often highly unpleasant. The gear noise originates at gear mesh. Transmission Error acts as an excitation source and these vibrations pass through gears, shafts and bearings to the housing which vibrates to produce noise on surrounding air. As microgeometry optimization target to reduce the fundamental excitation source of the noise, it has been favored method to tackle gear whine noise, especially for manual transmission. However, practicality of microgeometry optimization for the planetary gear system has been still in question, because of complex system structure and interaction among multi mesh gear sets make it hard to predict and even harder to improve. In this paper, successful case of whine noise improvement by microgeometry is presented.

With its advantage on the economic and environmental reason the preference of vehicles with diesel engine is growing in the domestic market as well as European market. And automobile makers are enthusiastic in the development of diesel engine vehicles with more comfortable interior atmosphere in order to meet consumers' requirements. Generally, when compared with gasoline engine, diesel engine has much bigger vibratory input to the mounting structure and produces higher level in interior noise and body vibration. In this paper, the improvement of NVH quality at the idle state of an SUV car with DI diesel engine has been achieved through tuning engine mounts based on TPA (Transfer Path Analysis) for low frequency vibration and interior booming noise.

There are some problems “windows fog up a lot” for ventilation system. We have Test Development Procedure to prevent the fog problems. But, Many fog problems occurred in the cars that we made. So in this paper, new ventilation system is needed and developed. The Smart Ventilation System automatically controls indoor air quality even though the blower motor is off. There are two sensors that is used for AutoDefogSensor system and CO2 CONTROL system.. The sensor is on when blower motor and heater control is off. We use these signals and make new ventilation logics. We evaluate this system in chamber & '13 winter test in USA.

The power trunk lid system is a device that automatically opens and closes the trunk lid by motor, for the purpose to improve user’s convenience. This technology was applied only to high-end large cars such as Equus and Genesis. But as preference for high convenience features increases, the scope of application is gradually expanding to semi-large and mid-sized cars. Therefore, the necessity of securing profitability through cost reduction was emerged, and it made us to develop the power trunk lid system by spindle drives. Compared to the conventional swing arm drive type, the spindle drive type may achieve cost savings, lightness and easy of assembly by optimizing the required motor specifications. However, since it uses a planetary gear with high gear ratio and the high rotation speed of the motor, operating noise is relatively large.

In this paper, we focused on the robust wiping performance of high speed driven condition as an important situation for vehicle safety. Frist, we selected appropriate wiper performance parameter to accurately predict its ability not only systematic point but also vehicle point. Second, we obtained parameter sensitivity of wiper high-speed performance using DFSS technique. Third, we developed prediction and optimization tool using commercial program; Excel and Visual Basic. Finally, we improved our tool to compare vehicle test and then modified prediction coefficient for the accuracy of tool. Thus, we proposed a systematic tool to predict wiping performance in high speed vehicle, and successfully obtained efficiency when we developed the new project’s wiper performance.

Shudder vibration of a hydraulic power steering system during parking maneuver was studied with numerical and experimental methods. To quantify vibration performance of the system and recognize important stimuli for drivers, a shudder metric was derived by correlation between objective measurements and subjective ratings. A CAE model for steering wheel vibration analysis was developed and compared with measured data. In order to describe steering input dependency of shudder, a new dynamic friction modeling method, in which the magnitude of effective damping is determined by average velocity, was proposed. The developed model was validated using the measured steering wheel acceleration and the pressure change at inlet of the steering gear box. It was shown that the developed model successfully describes major modes by comparing the calculated FRF of the hydraulic system with measured one from the hydraulic excitation test.

The method of Front End Auxiliary Drive (FEAD) system optimization can be divided into two ways. One is to use a mechanical device that decouples crank pulley from torsional vibration of crank shaft by using characteristics of spring. The other is to control belt tension through auto-tensioner in addition of alternator pulley device. Because the former case has more potential to reduce belt tension than the latter case, the development of mechanically decoupled crank pulley, despite of its difficulty of development, is getting popular among the industry. This paper characterizes latest crank pulley technologies, Crank Decoupler and Isolation Pulley, for torsional vibration reduction through functionality measurement result which composed of irregularity, slip, tensioner movement, belt span vibration, bearing hubload of idler and so on. Also it investigates their potential of belt tension reduction through steady state point fuel consumption test on dynamometer.

In order to utilize in-vehicle systems efficiently, many vehicles are becoming equipped with integrated controls near the center fascia or the control box. However, the placement of these control systems can cause safety issues and risks due to visual distractions. In this study, we proposed a new integrated touch screen on the steering wheel. For this experiment, a control system was placed on the steering wheel or the center fascia. 15 participants were required to drive while utilizing vent and navigation control tasks regarding four different locations. Three of these locations were based on the steering wheel (center, upper right, lower right) and one location on the center fascia. Afterwards, the task completion time and visual distraction rate of the different locations were measured and compared. The results showed that a touch screen placed on the upper right section of the steering wheel had better performance and lower user discomfort.

As the AVN display in the car interior becomes larger and located above the center fascia, the driver's visual visibility is becoming important. In addition, since an expensive touch sensor is installed, a transparent electrode cost reduction technology for a display touch sensor that can replace an indium material, which is an expensive rare metal, is required. In this paper, we developed new transparent electrode materials and manufacturing methods for the touch sensor film which light reflectance is low and flexible without a separate low-reflection multi-layer, so that the design freedom is high and the material cost is low. By optimizing the amount of fluorine doping ratio in tin oxide, excellent electrical conductivity and high optical transmittance are secured, and the surface reflectance is reduced by adjusting the diameter and length of the silver nanowire. As a result, it was shown that the AVN display image and font readability was improved.

The subject of this study is a centrifugal compressor for Fuel Cell Electric Vehicles (FCEV). Recently there is a growing interest in FCEVs since they are considered a realistic solution to environmental regulations for passenger cars to reduce emissions. Water vapor is the only byproduct of a reaction in the Proton Electrolyte Membrane (PEM) fuel cell stack which generates electricity with oxygen from the surrounding air and hydrogen from a fuel tank. Auxiliary systems called Balance of Plant (BOP) serve to provide air and hydrogen to the stack in a correct ratio. The compressor is one of key components of this system because compression of the intake air brings an increase in efficiency and power density of the FCEV. This paper presents the characteristics of a 10 kW class centrifugal compressor with an oil-free bearing system. It consists of a shaft, two airfoil journal bearings and a pair of thrust bearings.

Design optimization of a vehicle is required to increase a product value for noise and vibration performances and for a fuel-efficient car. This paper describes the development process of a high stiffness and lightweight vehicle. A parameter study is carried out at the initial stage of design using the mother car, and a design guide with a good performance is achieved early prior to the development of the proto car. Influences of body stiffness based on the relative weight ratio of the floor and side structures are analyzed. Results show that bending and torsional stiffness has a significant effect on weight distribution ratio. Influences of the distribution of side joint stiffness are analyzed through numerical experiments. Results reveal that the stiffness difference between the upper and lower parts should be small to increase the stiffness of a body.

With the recent development of technologies for interpreting vibration and noise of vehicles, it has become possible for carmakers to reduce idle vibration and driving noise in the phase of preceding development. Thus, the issue of noise generation is drawing keen attention from production of prototype car through mass-production development. J. D. Power has surveyed the levels of customer satisfaction with all vehicles sold in the U.S. market and released the Initial Quality Study (IQS) index. As a growing number of emotional quality-related items are added to the IQS evaluation index, it is necessary to secure a sufficiently high quality level of low-frequency speaker sound against rattle noise. It is required to make a preceding review on the package tray panel, which is located at the bottom of the rear glass where the woofer speakers of a passenger sedan are installed, the door module panel in which the door speakers are built.

The Design For Six Sigma (DFSS) process consists of four phases, identification & definition of opportunity, concept development, design optimization, and design verification. In the phase of concept development, TRIZ (Russian acronym for Theory of Inventive Problem Solving) is useful for creating new ideas from the present ideas, which includes the trimming strategy, the antidote strategy, and the picket fence strategy. In this paper, systems of a vehicle such as Variable Compression Ratio (VCR) engine, windshield wiper blade, and Continuously Variable Valve Actuation (CVVA) of engine, are selected and new concepts for each system are created by applying the previously mentioned three strategies. FMEA (Failure Mode and Effects Analysis), the latter part in the phase of concept development in DFSS, is conducted for newly generated concepts of systems that are mentioned above. As a result of FMEA, it is found that the wind lift of the wiper blade can be a serious problem.

Pressure variation during engine combustion generates torque fluctuation that is delivered through the driveline. Torque fluctuation delivered to the tire shakes the vehicle body and causes the body components to vibrate, resulting in booming noise. HKMC (Hyundai Kia Motor Company)’s TMED (Transmission Mounted Electric Device) type generates booming noises due to increased weight from the addition of customized hybrid parts and the absence of a torque converter. Some of the improvements needed to overcome this weakness include reducing the torsion-damper stiffness, adding dynamic dampers, and moving the operation point of the engine from the optimized point. These modifications have some potential negative impacts such as increased cost and sacrificed fuel economy. Here, we introduce a method of reducing lock-up booming noise in an HEV at low engine speed.

This research aims to develop an inverse control method capable of adaptively simulating dynamic models of car subsystems in the rig-test condition. Accurate simulation of the actual vibration conditions is one of the most crucial factors in realizing reliable rig-test platforms. However, most typical rig tests are conducted under simple random or harmonic sweep conditions. Moreover, the conventional test methods are hard to directly adapt to the actual vibration conditions when switching the dynamic characteristics of the subsystem in the rig test. In the present work, we developed an inverse controller to adaptively control the vibration exciter referring to the target vibration signal. An adaptive LMS filter, employed for the control algorithm, updated the filter weights in real time by referring to the target and the measured acceleration signals.

The purpose of the study is to investigate the ergonomic issues for control types and menu design types of in-vehicle information system (IVIS). The results showed that 1) linear-type controls with linear-type menu design had better performance 2) rotary-type control with rotary-type menu design had good subjective preference score 3) the performance and subjective preference of IVIS interface were strongly influenced by the compatibility between control types and menu design types of IVIS 4) there was a tendency that the performance of IVIS tasks was better when the display was located at higher level on center fascia. The results can be applied to develop a new control and menu design of IVIS from ergonomic view points.

For optimizing the performance of SI engine such as engine torque, fuel consumption, and emissions, various types of system for variable valve timing were developed by many automotive researchers. In this paper, we investigated the relationship between valve timing and intake orifice noise, and suggested how to improve NVH (Noise, Vibration and Harshness) performance as well as engine torque. Some experiments using the engine dynamometer were carried over about 150 different operating conditions. BEM analysis was also conducted in order to calculate acoustic modes of intake system. The results show that the valve timing and overlap of breathing systems have influence on NVH behavior, especially intake orifice noise over whole range of operating conditions. Valve timing and overlap of intake and exhaust valve were optimized in the view of sound quality as well as overall noise level.

In order to apply an effective noise reduction treatment determining the contribution of different engine components to the total sound perceived inside the cabin is important. Although accelerometer or laser based vibration tests are usually performed, the sound contributions are not always captured accurately with such approaches. Microphone based methods are strongly influenced by the many reflections and other sound sources inside the engine bay. Recently, it has been shown that engine radiation can be effectively measured using microphones combined with particle velocity sensors while the engine remains mounted in the car [6]. Similar results were obtained as with a dismounted engine in an anechoic room. This paper focusses on the measurement of the transfer path from the engine to the vehicle interior in order to calculate the sound pressure contribution of individual engine sections at the listener's position.

Ensuring spray robustness of gasoline direct injection (GDI) is essential to comply with stringent future emission regulations for hybrid and internal combustion engine vehicles. This study presents experimental and numerical assessments of spray for lateral-mounted GDI sprays with two different plume arrangements to analyze spray collapse characteristics, which can significantly deteriorate the atomization performance of fuel sprays. Novel spray characterization methods are applied to analyze complex spray collapse behaviors using diffusive back-illuminated extinction imaging (DBIEI) and 3D computed tomographic (CT) image reconstruction. A series of computational fluid dynamics (CFD) simulations are performed to analyze the detailed spray characteristics besides experimental characterization. Spatio-temporal plume dynamics of conventional triangle-pattern spray are evaluated and compared to a plume pattern with an inversed T pattern that has more open space between plumes.

The windshield is an integral part of almost every modern passenger car. Combined with current developments in the automotive industry such as electrification and the integration of lightweight material systems, the reduction of interior noise caused by stochastic and transient wind excitation is deemed to be an increasing challenge for future NVH measures. Active control systems have proven to be a viable alternative compared to traditional passive NVH measures in different areas. However, for windshield actuation there are neither comparative studies nor actually established actuation concepts available to the automotive industry. This paper illustrates a comparative conceptual study on windshield actuation for the active control of wind noise in a passenger car. Making use of an experimental modal analysis of the windshield installed in a medium-sized vehicle, a reduced order numerical simulation model is derived.