Feature | Technical
Nak Kyoung Kong, Kihong Lee, and Jongmin Park, Hyundai Motor Company Citation: Kong, N.K., Lee, K., and Park, J., “Study on Basic Principles of Operation Noise of Wiper System on Vehicle,” SAE Technical Paper 2019-01-1421, 2019, doi:10.4271/2019-01-1421.
Study on Basic Principles of Operation Noise of Wiper System on Vehicle Introduction The wiper system consists of a motor, linkage, arm, and blade, which provides a clear front view to the driver by removing rain, snow, and foreign matter from the windshield glass. It is a system component that requires a robust design to meet system rigidity, scrubbing performance, and operating noise in any external environment to provide the driver with a front view. However, after analyzing the customers’ complaints about the wiper system, it was confirmed that the customers were most dissatisfied with the noise / vibration of the wiper blade. As a result of analyzing the customer complaints by car class, it was confirmed that the noise of the luxury car was more complaining than the small and medium sized passenger car. We have confirmed that our evaluation criteria focus on emotional evaluation that is not sufficient to improve the various wiper operating noises that customers are dissatisfied with. Therefore, this paper proposes a quantitative analysis method that can analyze various noise that can occur in wiper system. The human auditory system consists largely of the outer ear, the middle ear, and the inner ear. The sound transmission path consists of the cranium -> outer ear canal -> eardrum -> Ossicle -> cochlea. The basement membrane of the cochlea is called the basal membrane, which is made up of hard, short fibers, but it is made up of long, soft fibers going to the end of the cochlea. Due to this structural difference, the basement membrane of each part reacts to different frequencies. That is, since the basement membrane at different positions
along the frequency of the sound is bent, the activated hair cells are different. The treble in the near basal membrane resonates well in the remote basement membrane. Important physical quantities of sound are frequency and intensity. A person can distinguish a sound by the difference between frequency and intensity. The difference in frequency can be determined from what type of hair cells the vibration is detected, and the difference in frequency is recognized by the pitch of the sound. The intensity of the sound can be determined by the magnitude of the signal detected by the hair cell, and the intensity of the sound is divided by the amplitude. In other words, due to the structural form of the human ear, it is impossible to recognize the quality of sound simply based on the size of the sound. While we still manage the wiper noise based on the noise level only for the wiper noise, other competitors who recognize the need to improve the noise quality manage the wiper noise by introducing psychoacoustic quality standards using Zwicker parameters have. Competitors’ evaluation criteria for noise evaluation are based on evaluation of sound quality for emotional, as well as performance evaluation criteria of blades that meet various environmental conditions that have the greatest influence on wiper noise. In this paper, we propose quantitative emotion noise discrimination for wiper blade noise and establishment of verification method considering environmental impact.
Noise Measurement and Evaluation For this study, we recorded the wiper operating noise by clas-sifying large
FIGURE 1. Customer Claims of Wiper System
26 | March 2022
ABSTRACT The wiper system consists of a motor, linkage, arm, and blade, which provides a clear front view to the driver by removing rain, snow, and foreign matter from the windshield glass. It is a system component that requires a robust design to meet system rigidity, scrubbing performance, and operating noise to any external conditions to provide the driver with a front view. In recent years, however, customer complaints about wiper noise have increased as automobile engine and noise levels have decreased. Based on the analysis of wiper noise, this paper presents quantitative judgment criteria for various wiper noises. In addition, we predict the change of wiper noise to environmental factors through the sound field analysis and propose the solution. / medium / small / small / small / RV vehicles. The sensory evaluation was carried out by 82 customers using data recorded in the interior of the vehicle to classify the preferred / non-preferred vehicles for wiper noise. Based on the above results, we analyzed the outdoor / indoor noise characteristics, the influence analysis according to the applica-tion of the sound insulation film, the noise of the motor & linkage, and the noise trend of the new / aged blades. As a result, it was possible to distinguish the non-preferred vehicle group in which the quality of the wiper noise was rapidly deteriorated. Table 2 shows the results and examples of preference group and non-favored group vehicle classification. Based on the results of this evaluation, we conducted a comparative analysis with the vehicles clas-sified as the preferred group for the vehicles classified as non preferred wiper noise. Visualization Noise Analysis We compared the operating noise of new and aged wiper system for the preferred and non - preferred vehicles. The aged wiper system was used for comparative evaluation after confirming satisfaction of blade pressure, attack angle, overrun specification after 300,000 cycles of continuous oper-ation according to the durability evaluation specification without replacing the wiper blade. Visualization noise measurements were performed in indoor and outdoor of the car under the engine off and wet windshield condition in the anechoic room for the preferred and non - preferred group vehicles.
