• Journal of KSNVE
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• v.9 no.4
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• pp.841-848
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• 1999

In the quality assurance check process of DC motor systems, even though the overall sound pressure level is acceptable, there is an incident that subjective evaluation leads to failure in product quality due to annoying noise. This kind of problem may be originated from the manufacturing or assembly process. In this paper, the transient spectral analysis, or the time-frequency analysis is applied to the noise quality problem. For the case study, the cause of annoying noise in the wind shield wiper motor is experimentally analyzed in detail. It is concluded that the defect in the shaft causes the impact noise which is not detectable by steady spectral analysis. Also demonstrated is how the time-frequency analysis is effectively applied to the annoying noise identification of the rotor-gear system.

• Journal of KSNVE
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• v.8 no.5
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• pp.862-869
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• 1998

The interior noise generated by the windshield wiper system including a wiper motor, the motor mountings and linkages is considered as a structure-borne noise. The structureborne noise is closely related with the system vibration which was transmitted into interior cabin through the car body. In this study, the frequency characteristics of vibration in the wiper motor system were first identified through the frequency analysis. Then effects of the wiper motor mountings and linkages on the vehicle interior noise were studied through in-vehicle measurements. Finally a possibility of noise reduction at a certain frequency was revealed from the study.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.210-215
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• 2001

The pole antenna of vehicles for AM/FM radio broadcasting receptions has many probems, such as damageable mechanical system and noise etc. It is considered that noise is composed of the structural vibration noise and the air flow induced aerodynamic noise. Also we find out that the setting process of a printed on-glass automobile antenna has many difficulties. Recently, the above mentioned problems can be reduced by employing enhanced wiper antenna which utilizes the windshied wiper arm. The new system is a passive antenna. In this study, experiments for the characteristics of a wiper antenna by measuring the SWR, radiation pattern and received powe have been carried out. The experimental results show that the efficiency of the wiper antenna has better performance than any other antenna.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.88-96
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• 2008

Effects of the duct inlet guide vane on the flowrate distribution characteristics of the defroster nozzle exit in a defrost duct system were investigated experimentally to design the optimum heating, ventilation and air conditioning (HVAC) system applied in an automotive compartment. A 3-dimensional hot-wire anemometer system was used to measure the velocity field in the vicinity of the defroster nozzle jet flow and the velocity distributions near the windshield interior surface. At first, two cases of with- and without-duct inlet guide vanes were considered as the test condition, and then three cases of the duct inlet guide vane were tested to determine the optimum guide vane shape and their positions. The arrangement of the duct inlet guide vanes has an effect on the improved flowrate distribution at the defroster nozzle exit and near the windshield interior surface. However, the application of the lots of guide vane to control the flow direction leads to increase the flow resistance, resulting in the decreased flowrate issuing from the defroster nozzle. The shape of the duct inlet guide vane affects not only the flowrate distribution between the driver side and the assistant driver side but also the reduction of the flow resistance in the defrost duct system.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.7-12
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• 2013

Tin oxide thin-films have been widely applied in various fields of high-technology industries due to their excellent physical and electric properties. Those applications are found in various sensors, heating elements of windshield windows, solar cells, flat panel displays as tranparent electrodes. In this study, we conducted an experiment for the deposition of $SnO_2$ on glass of 2nd Gen. size for the effective development of large-scale backplanes. As deposition temperatures or flow rates of the $SnCl_4$ as a precursor changed, the thickness of tin oxide thin-films, their sheet resistances, transmittances, and hazes varied considerably.