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9732793 Low noise muffler development by optimization of muffler internal structure - study on muffler internal structure to use multivariate analysis
Abstracts / JSAE Review 19 (1998) 89-109 9732711 A Low-pass filtering Method for Evaluating Display Legibility Masami Funakawa (Nissan Motor Co. Ltd.) This paper concerns a low-pass filtering method for evaluating the visibility of shapes. With this method, observers discriminate the shapes of images that are filtered in gradually lower spatial frequencies. Legibility is evaluated by measuring the discrimination threshold cut-off frequencies. The method has been validated in practical situations where visual information carried by high spatial frequencies is degraded. Such situations are surprisingly common under unfavourable conditions, including peripheral viewing, mesopic or scotopic vision, isoluminance, image motion, and also in the eyes of elderly persons and clinically impaired eyes. The numerals of 14 font families were evaluated using this method. The legibility evaluations showed good agreement among the observers, and several working hypotheses were suggested about the legibility of characters. 9732720 Development of a Color Irregularity Evaluation Method for Interior Resin Parts Yoshihiko Tanaka, Shinya Otonari, Hiroyuki Itou (Kanto Auto Works, Ltd.), Toshikazu Ishihara, Mikiko Kawasumi, Miyuki Yamakawa (Toyota Central R&D Labs., Inc.) The matching of colors of the adjoining interior parts of an automobile is an important issue in interior design. Presently, the grained leather patterns is arranged on the surfaces of the interior parts, and this pattern makes it difficult to identify color irregularities during the visual sensory evaluation. An evaluation formula is used to evaluate the measured colors, but there is the problem that the experimental evaluation does not correspond with the visual sensory evaluation. To accurately reproduce the visual sensory evaluation, we have developed a new evaluation technique. This paper reports on this new technique. 9732739 Analysis of Smell in Automotive Cabin Miho Matsuo, Hideki Ono (Toyota Motor Corporation), Shigeyuki Sato, Kiyomi Sakakibara, Kazumi Kaitani (Toyota Central R&D Labs., Inc.) In the cabin of vehicle, there are several kinds of smell, which are related to comfortability, respectively. The "new car smell" reflects the change of user-taste, and recently, more comfortable "new car smell" is being required. This paper is concerned with analysis of the correlation between the sensory evaluation and the gas analysis of the "new car smell" which is composed of many kinds of volatile organic compounds. 9732748 A Study of Driver's Behavior in Turning a Curve Shigenori Takimoto, Toshitake Kawai, Junji Yuzuriha, Yasuo Shimizu (Honda R&D Co., Ltd.) This study concerns how a driver gets visual information in driving. Preview vision information is an important factor in driver steering maneuver. We made experiments to measure the driver's eye movement using an eyemark recorder with a subject driving an actual vehicle. Subjects are 3 expert, 5 general and 3 beginner drivers. We compute the driver's preview time from eye movement data. The results show that driver's preview time is approximate 1.2 s in cornering. 9732757 Color Image Processing Methods for Driving Situation Understanding Toshio Ito, Kenichi Yamada (Daihatsu Motor Co., Ltd.) We are developing a method for recognizing the road lane as well as recognizing and ascertaining the position and motion of a preceding vehicle. In our previous method, we used an edge histogram that is a histogram of a differentiated black and white shading image to estimate the segment components, thereby enabling recognition of a preceding vehicle and the road lane. In this paper, we propose another recognition method for the driving environment by using color information in addition to the methods mentioned above. 9732766 On the Regulation of Automobile Noise Emission Shigehiko Kaneko (The University of Tokyo)
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In order to reduce road traffic noise, regulations of noise emission of automobiles have been intensified in industrialized countries. In this paper, an overview of the history of the automobile noise regulations and recent situations in Japan, a brief explanation of countermeasures against noise emission, and the background of introducing Leq, are described. 9732775 Analysis of the Acoustic Radiation Characteristics of Engine Compartment and Application for Reduction of Vehicle Exterior Noise Yasuhiko Nishimura, Mikio Noba (Toyota Motor Corporation) It has become more difficult to reduce vehicle exterior noise, considering the trade-off between noise reduction and cooling efficiency or power. In this paper, the acoustic radiation characteristics for some vehicles with countermeasures against noise radiated from the engine are investigated. Using the reciprocity method to obtain the acoustic response makes the data more accurate and gives the contributions for portions of noise sources, such as engine surface, in detail. These results provide the countermeasures which have the greatest effect on reduction of exterior noise. 9732784 Application of a Sound Insulation Panel with Ventilation Holes to the Engine Under-Cover Keijiro Iwao, Yuji Shimpo (Nissan Motor Co., Ltd.), Haruki Yashiro (Nissan Diesel Motor Co., Ltd.) Reducing engine noise is one of the most important issues in lowering the external noise level of vehicles. An engine under-cover is one effective measure for reducing engine noise. However, the size of the under-cover is limited by the need to ensure sufficient engine cooling performance. To solve this problem, a new sound insulation panel with ventilation holes was developed and applied to the engine under-cover. The panel accomplishes sound insulation by controlling the acoustic anti-resonance of sounds transmitted through the ventilation holes. This paper describes guidelines for applying the panel to the engine under-cover from the viewpoints of acoustics and fluid dynamics. 9732793 Low Noise Muffler Development by Optimization of Muffler Internal Structure - Study on Muffler Internal Structure to Use Multivariate Analysis Hisashi Natori (Hino Motors, Ltd.) New exterior noise regulations will be executed in the near future. The development of exterior noise reduction is difficult, because a lot of devices are related. Since the exhaust noise is the main noise source of the exterior noise, it is important to decrease the exhaust noise. This was achieved by using multivariate analysis for the low noise muffler. 9732801 New Measuring Technique of Cylinder Pressure Spectrum and its Application to Combustion Noise Reduction- Time-Frequency Analysis of Combustion Excitation Using Wavelet Transform Analysis Yuji Yajima, Kazuhiro Nakashima (Mitsubishi Motors Corporation) Fuel injection systems of diesel engines are tending toward more high-pressure injection to achieve fuel economy and reduction of exhaust gas emission. Under the influence of high-pressure injection, combustion noise increases to a great extent. In place of the traditional Fourier transform, the wavelet transform was introduced for the analysis of time-local spectral vibrations in combustion pressure in cylinders. Two portions of combustion excitation induced by both premixed combustion and diffusion combustion were extracted separately. The former can be reduced by injection control of the common-rail injection system such as injection rate shaping and pilot injection, and the latter is still dominant at higher engine sped. This is a good indication to a countermeasure plan for combustion noise reduction. 9732810 Noise Analysis of Stainless Steel Exhaust-manifold Hisanaga Matsuoka, Tetsuya Hyakutake (Nippon Soken, Inc.), Kenichi Yamamoto (Toyota Motar Corporation) In order to research the mechanism of high frequency noise generation of a stainless steel exhaust-manifold, we made the experiment of speaker excitation or numerical calculation of a model pipe. The results
103
In order to reduce road traffic noise, regulations of noise emission of automobiles have been intensified in industrialized countries. In this paper, an overview of the history of the automobile noise regulations and recent situations in Japan, a brief explanation of countermeasures against noise emission, and the background of introducing Leq, are described. 9732775 Analysis of the Acoustic Radiation Characteristics of Engine Compartment and Application for Reduction of Vehicle Exterior Noise Yasuhiko Nishimura, Mikio Noba (Toyota Motor Corporation) It has become more difficult to reduce vehicle exterior noise, considering the trade-off between noise reduction and cooling efficiency or power. In this paper, the acoustic radiation characteristics for some vehicles with countermeasures against noise radiated from the engine are investigated. Using the reciprocity method to obtain the acoustic response makes the data more accurate and gives the contributions for portions of noise sources, such as engine surface, in detail. These results provide the countermeasures which have the greatest effect on reduction of exterior noise. 9732784 Application of a Sound Insulation Panel with Ventilation Holes to the Engine Under-Cover Keijiro Iwao, Yuji Shimpo (Nissan Motor Co., Ltd.), Haruki Yashiro (Nissan Diesel Motor Co., Ltd.) Reducing engine noise is one of the most important issues in lowering the external noise level of vehicles. An engine under-cover is one effective measure for reducing engine noise. However, the size of the under-cover is limited by the need to ensure sufficient engine cooling performance. To solve this problem, a new sound insulation panel with ventilation holes was developed and applied to the engine under-cover. The panel accomplishes sound insulation by controlling the acoustic anti-resonance of sounds transmitted through the ventilation holes. This paper describes guidelines for applying the panel to the engine under-cover from the viewpoints of acoustics and fluid dynamics. 9732793 Low Noise Muffler Development by Optimization of Muffler Internal Structure - Study on Muffler Internal Structure to Use Multivariate Analysis Hisashi Natori (Hino Motors, Ltd.) New exterior noise regulations will be executed in the near future. The development of exterior noise reduction is difficult, because a lot of devices are related. Since the exhaust noise is the main noise source of the exterior noise, it is important to decrease the exhaust noise. This was achieved by using multivariate analysis for the low noise muffler. 9732801 New Measuring Technique of Cylinder Pressure Spectrum and its Application to Combustion Noise Reduction- Time-Frequency Analysis of Combustion Excitation Using Wavelet Transform Analysis Yuji Yajima, Kazuhiro Nakashima (Mitsubishi Motors Corporation) Fuel injection systems of diesel engines are tending toward more high-pressure injection to achieve fuel economy and reduction of exhaust gas emission. Under the influence of high-pressure injection, combustion noise increases to a great extent. In place of the traditional Fourier transform, the wavelet transform was introduced for the analysis of time-local spectral vibrations in combustion pressure in cylinders. Two portions of combustion excitation induced by both premixed combustion and diffusion combustion were extracted separately. The former can be reduced by injection control of the common-rail injection system such as injection rate shaping and pilot injection, and the latter is still dominant at higher engine sped. This is a good indication to a countermeasure plan for combustion noise reduction. 9732810 Noise Analysis of Stainless Steel Exhaust-manifold Hisanaga Matsuoka, Tetsuya Hyakutake (Nippon Soken, Inc.), Kenichi Yamamoto (Toyota Motar Corporation) In order to research the mechanism of high frequency noise generation of a stainless steel exhaust-manifold, we made the experiment of speaker excitation or numerical calculation of a model pipe. The results