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Low-frequency road noise analysis based on acoustic excitation tests
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Abstracts/JSAE Review 18 (1997) 185-209
9638761 Influence of Piston Rotational Motion on Piston Friction Hiroaki Watanabe, Hideyuki Miyasaka, Yasuo Takashima, Kazuhiko Shirane, Masaharu Kitamura (UNISIA JECS Corp.) In order to reduce piston friction, the effects of piston rotational motion using piston-pin offset variation were studied through both experimental and theoretical analysis (including EHL computations). As a result, it was found that larger piston-pin offsets to the thrust side result in higher piston friction, especially in the expansion stroke. The calculated results also demonstrate that this difference in friction is brought about by the difference in oil film formation as related to skirt inclination. 9638770 Improvement of Thermal Efficiency by Offsetting the Crankshaft Center to the Cylinder Bore Center Shinichi Sano, Eiichi Kamiyama, Tatehito Ueda (Toyota Motor Corp.) To improve the thermal efficiency especially in part load condition, experimental engines which have different offset distance between crankshaft and cylinder bore center were made. By offsetting the crankshaft center to the cylinder bore center, thermodynamical improvement derived from the change of cylinder pressure trace was observed, as well as the reduction of friction loss due to lowered piston side force. As a result, about 3% improvement of BSFC was confirmed in the low speed part load condition on the experimental engine. 9638789 Effect of Oil Supply Rate on Temperature and Contact of a Con-Rod Big End Bearing Shigeo Suzuki, Toshihiro Ozasa, Takashi Noda (Toyota Central R & D Labs., Inc.), Toshiaki Konomi (Toyota Motor Corp.) An engine was modified to measure the oil supply rate to a con-rod big end bearing, the bearing temperature and the contact between the journal and the bearing were measured with the oil supply rate changed in order to investigate lubrication characteristics. When the oil supply rate was slightly decreased, the contact hardly changed under almost all operating conditions even with increasing temperature. When the oil supply rate was further decreased, the contact rapidly increased under high speed conditions. The cause of the above is discussed using the theoretical calculations and the observation of a transparent bearing. 9638798 Low-frequency Road Noise Analysis based on Acoustic Excitation Tests Shinichi Maruyama, Akihiko Hasegawa, Janichi Aoki (Nissan Motor Co. Ltd.) A technique based on the reciprocity principle was developed for measuring the mechanical-acoustical transfer functions of road noise induced by forced displacement inputs from the suspension. With this technique, acoustic excitation is applied to a vehicle and the resulting constraint forces of the tires are measured by means of tri-axial load cells. Examples are given of the application of this technique to the analysis of low-frequency road noise. The results indicated that the reciprocity technique is applicable to a fully trimmed vehicle, and that it is often cheaper and more convenient to use than the shaker-based excitation method. 9638806 Drum Test Method of Tire Road Noise - - Microphone Scanning Method using Medium Texture Surface (NTS-1) Satoshi Konishi, Toshiaki Fujino, Kouichi Usami, Naotaka Tomita, Toshio Ozaki (Bridgestone Corp.) It is well "known that tire road noise is influenced by road surface, vehicle type and environmental factors. In order to evaluate the tire noise level more accurately, a new drum method using Noise Test Surface (NTS-1) and microphone scanning analysis is investigated. The comparison of vehicle and the new drum method shows a good correlation within _ 0.4dB(A) of estimate precision and 0.84 ~ 0.99 of correlation factor. 9638815 Analysis on Idle Shake using Taguchi Method Hiroshi Isoyama, Hiroaki Hoshino, Yoshito Watanabe (Nissan Diesel Motor Co., Ltd.) This study investigates a technique to reduce the idle shake of a truck cabin. Modifications of several factors such as the specifications of
chassis and cab suspension systems were conducted using the Taguchi method. Experimental and computational parameter studies were conducted using an orthogonal array L18 to determine the effect of each parameter. The idle shake which is caused by engine speed fluctuation and the operation of the air conditioner compressor was reduced by selecting optimum design parameters. This approach enables design engineers to select design parameters more effectively than the former trial and error method.
9638824 Engine Room Enclosure with Sound Absorbing Materials Masato Abe, Nobuhiko Narita (NOK MEGULASTIK) The area of the engine enclosure, especially lining the engine cover with sound absorbing materials, has become increasingly important for reducing exterior noise of passenger car. In this paper, we show the characteristics of these sound absorbing materials. 9638833 Study to Improve Sound-absorbing Characteristics of Headliner for Trucks Akira Togo, Harusige Yamamura, Tai Urazi (Mitsubishi Motors Corp.) To improve the sound-absorbing characteristics of interior parts is important in reducing the engine noise of trucks. The headliner has a large surface area and high sound absorption power. Therefore it is effective to improve the sound-absorbing power of the headliner. We studied the optimum materials and structure of a headliner to give good sound-absorbing characteristics, light weight and high rigidity for trucks, using polypropylene based stampable sheet and expansion molding. 9639094 Prediction of Sound Absorption and Insulation Material Properties for Reducing Interior Noise of Trucks Hideki Murata, Atsuhiro Matsuda (Mitsubishi Motors Corp.) This paper presents a method to predict sound absorption and insulation properties of truck cab trims made by multi layered materials, that have complicated acoustical and mechanical characteristics. In this method, essential physical properties are obtained by experiments in normal incidence condition, and the influence of plate vibration and supporting conditions are also considered. The effectiveness of this method is demonstrated by an application for improvement of headliners. 9638842 Development of a System for Evaluating Car Interior Sound QuarRy During Acceleration Koichi Onishi, Eriko Horiuchi, Tomoyuki Matuzawa, Tetsuya Kougo (Nissan Motor Co., Ltd.) Reduction of noise is an important factor in improving the quality of vehicles. In addition to noise reduction, much importance has recently been attached to sound quality. In this research, a study was made of the relationship between the spectrum structure of car interior noise and the results of subjective evaluations of sound quality. As a result, a regression equation was obtained that shows the relationship between them. A compact system was also developed which is well suited to vehicle experiments. Simple to operate, this system provides evaluation results that are closer to human auditory sensibilities than previous equipment.
9638851 Evaluation Method of Engine Sound Quality for Compact Sedan with 4 Cylinder Engine during Acceleration Noriyoshi Terazawa, Yoshihiko Kozawa (Toyota Central R & D Labs., Inc.), Tatsuo Shuku (Toyota Motor Corp.) This paper describes an objective evaluation method of engine sound quality for a compact sedan with a 4 cylinder gasoline engine during acceleration. Two factors, 'annoying' and 'metallic', were extracted from engine sound by subjective evaluation test. The first factor, 'annoying', was expressed by booming level and rumble level. The second factor, 'metallic', was expressed by metallic sound index (new physical index). By using these objective factors and the results of another subjective evaluation test, an objective evaluation method of engine sound quality was developed. Comparison of the objective rating of engine sound quality with the subjective rating showed a good correlation.
Abstracts/JSAE Review 18 (1997) 185-209
9638761 Influence of Piston Rotational Motion on Piston Friction Hiroaki Watanabe, Hideyuki Miyasaka, Yasuo Takashima, Kazuhiko Shirane, Masaharu Kitamura (UNISIA JECS Corp.) In order to reduce piston friction, the effects of piston rotational motion using piston-pin offset variation were studied through both experimental and theoretical analysis (including EHL computations). As a result, it was found that larger piston-pin offsets to the thrust side result in higher piston friction, especially in the expansion stroke. The calculated results also demonstrate that this difference in friction is brought about by the difference in oil film formation as related to skirt inclination. 9638770 Improvement of Thermal Efficiency by Offsetting the Crankshaft Center to the Cylinder Bore Center Shinichi Sano, Eiichi Kamiyama, Tatehito Ueda (Toyota Motor Corp.) To improve the thermal efficiency especially in part load condition, experimental engines which have different offset distance between crankshaft and cylinder bore center were made. By offsetting the crankshaft center to the cylinder bore center, thermodynamical improvement derived from the change of cylinder pressure trace was observed, as well as the reduction of friction loss due to lowered piston side force. As a result, about 3% improvement of BSFC was confirmed in the low speed part load condition on the experimental engine. 9638789 Effect of Oil Supply Rate on Temperature and Contact of a Con-Rod Big End Bearing Shigeo Suzuki, Toshihiro Ozasa, Takashi Noda (Toyota Central R & D Labs., Inc.), Toshiaki Konomi (Toyota Motor Corp.) An engine was modified to measure the oil supply rate to a con-rod big end bearing, the bearing temperature and the contact between the journal and the bearing were measured with the oil supply rate changed in order to investigate lubrication characteristics. When the oil supply rate was slightly decreased, the contact hardly changed under almost all operating conditions even with increasing temperature. When the oil supply rate was further decreased, the contact rapidly increased under high speed conditions. The cause of the above is discussed using the theoretical calculations and the observation of a transparent bearing. 9638798 Low-frequency Road Noise Analysis based on Acoustic Excitation Tests Shinichi Maruyama, Akihiko Hasegawa, Janichi Aoki (Nissan Motor Co. Ltd.) A technique based on the reciprocity principle was developed for measuring the mechanical-acoustical transfer functions of road noise induced by forced displacement inputs from the suspension. With this technique, acoustic excitation is applied to a vehicle and the resulting constraint forces of the tires are measured by means of tri-axial load cells. Examples are given of the application of this technique to the analysis of low-frequency road noise. The results indicated that the reciprocity technique is applicable to a fully trimmed vehicle, and that it is often cheaper and more convenient to use than the shaker-based excitation method. 9638806 Drum Test Method of Tire Road Noise - - Microphone Scanning Method using Medium Texture Surface (NTS-1) Satoshi Konishi, Toshiaki Fujino, Kouichi Usami, Naotaka Tomita, Toshio Ozaki (Bridgestone Corp.) It is well "known that tire road noise is influenced by road surface, vehicle type and environmental factors. In order to evaluate the tire noise level more accurately, a new drum method using Noise Test Surface (NTS-1) and microphone scanning analysis is investigated. The comparison of vehicle and the new drum method shows a good correlation within _ 0.4dB(A) of estimate precision and 0.84 ~ 0.99 of correlation factor. 9638815 Analysis on Idle Shake using Taguchi Method Hiroshi Isoyama, Hiroaki Hoshino, Yoshito Watanabe (Nissan Diesel Motor Co., Ltd.) This study investigates a technique to reduce the idle shake of a truck cabin. Modifications of several factors such as the specifications of
chassis and cab suspension systems were conducted using the Taguchi method. Experimental and computational parameter studies were conducted using an orthogonal array L18 to determine the effect of each parameter. The idle shake which is caused by engine speed fluctuation and the operation of the air conditioner compressor was reduced by selecting optimum design parameters. This approach enables design engineers to select design parameters more effectively than the former trial and error method.
9638824 Engine Room Enclosure with Sound Absorbing Materials Masato Abe, Nobuhiko Narita (NOK MEGULASTIK) The area of the engine enclosure, especially lining the engine cover with sound absorbing materials, has become increasingly important for reducing exterior noise of passenger car. In this paper, we show the characteristics of these sound absorbing materials. 9638833 Study to Improve Sound-absorbing Characteristics of Headliner for Trucks Akira Togo, Harusige Yamamura, Tai Urazi (Mitsubishi Motors Corp.) To improve the sound-absorbing characteristics of interior parts is important in reducing the engine noise of trucks. The headliner has a large surface area and high sound absorption power. Therefore it is effective to improve the sound-absorbing power of the headliner. We studied the optimum materials and structure of a headliner to give good sound-absorbing characteristics, light weight and high rigidity for trucks, using polypropylene based stampable sheet and expansion molding. 9639094 Prediction of Sound Absorption and Insulation Material Properties for Reducing Interior Noise of Trucks Hideki Murata, Atsuhiro Matsuda (Mitsubishi Motors Corp.) This paper presents a method to predict sound absorption and insulation properties of truck cab trims made by multi layered materials, that have complicated acoustical and mechanical characteristics. In this method, essential physical properties are obtained by experiments in normal incidence condition, and the influence of plate vibration and supporting conditions are also considered. The effectiveness of this method is demonstrated by an application for improvement of headliners. 9638842 Development of a System for Evaluating Car Interior Sound QuarRy During Acceleration Koichi Onishi, Eriko Horiuchi, Tomoyuki Matuzawa, Tetsuya Kougo (Nissan Motor Co., Ltd.) Reduction of noise is an important factor in improving the quality of vehicles. In addition to noise reduction, much importance has recently been attached to sound quality. In this research, a study was made of the relationship between the spectrum structure of car interior noise and the results of subjective evaluations of sound quality. As a result, a regression equation was obtained that shows the relationship between them. A compact system was also developed which is well suited to vehicle experiments. Simple to operate, this system provides evaluation results that are closer to human auditory sensibilities than previous equipment.
9638851 Evaluation Method of Engine Sound Quality for Compact Sedan with 4 Cylinder Engine during Acceleration Noriyoshi Terazawa, Yoshihiko Kozawa (Toyota Central R & D Labs., Inc.), Tatsuo Shuku (Toyota Motor Corp.) This paper describes an objective evaluation method of engine sound quality for a compact sedan with a 4 cylinder gasoline engine during acceleration. Two factors, 'annoying' and 'metallic', were extracted from engine sound by subjective evaluation test. The first factor, 'annoying', was expressed by booming level and rumble level. The second factor, 'metallic', was expressed by metallic sound index (new physical index). By using these objective factors and the results of another subjective evaluation test, an objective evaluation method of engine sound quality was developed. Comparison of the objective rating of engine sound quality with the subjective rating showed a good correlation.