エンジン燃焼騒音の音質を低下させるパワープラント固有モードの特徴分析
動画引用元論文
エンジン燃焼騒音の音質を低下させるパワープラント固有モードの特徴分析
- 著 者
- 小西 敬三、鳥居 建史、西川 智博
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol55, No.6, 2024.
- 発 行
- 2024年11月
- 要 旨
- 本研究では、エンジン燃焼騒音の音質を低下させるパワープラント固有モードの特徴を実験的モード解析によって分析した。その結果、エンジン燃焼騒音のハーフ次および奇数次成分を増大させる固有モードは、エンジン本体の弾性変形、特に主軸受キャップの変形によって生じることが明らかになった。さらに、エンジンの弾性変形が、次数ベース周波数応答関数の評価点であるマウントブラケットの変形と連成すると、燃焼騒音のハーフ次および奇数次成分はさらに増幅されることもわかった。
Speaker
小西 敬三 / Keizo Konishi
その他 執筆論文（共著含む）
エンジン音質改善のためのパワープラント固有モードの改善指針検討
- 著 者
- 鳥居 建史、小西 敬三、西川 智博、玉木 秀人、松村 雄一、吉村 卓也
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol56, No.4, 2025.
- 発 行
- 2025年6月
- 要 旨
- This paper discusses guidelines for power plant structural design to enhance the sound quality of engine combustion noise. Based on the modal analysis, guidelines for enhancement of power plant vibration modes were derived to reduce half-order and odd-order vibration at the resonance frequency of a power plant combining a four-cylinder engine with a transmission. The validity of the proposed guidelines was verified through finite element analysis using a simplified structure simulating a power plant.
有限要素モデルに基づくパワープラントの次数ベース周波数応答関数の計算法
- 著 者
- 西川 智博、鳥居 建史、小西 敬三、玉木 秀人、山口 亮
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol56, No.2, 2025.
- 発 行
- 2025年3月
- 要 旨
- This study reports the development of a method for calculating an Order-based FRF using CAE analysis with a finite element model (FEM) for enhancing the sound quality of engine combustion noise. An FEM was created from a power plant model equivalent to a bench vibration test, and it was confirmed that an Order-based FRF similar to the experiment could be calculated. In order to simplify the analysis model, verification was carried out, so the main motion system model was omitted and a method of inputting the excitation force to the main bearing was considered. As a result, it was found that an Order-based FRF equivalent to the actual machine experiment could be calculated with only the power plant structure model. By using the CAE analysis method constructed in this study to calculate the Order-based FRF, it is possible to identify the frequency band and mode of concern for sound quality deterioration and to consider countermeasures at the pre-prototype stage.
エンジン音質改善のためのパワープラント伝達関数の計測法と評価法
- 著 者
- 西川 智博、鳥居 建史
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol55, No.2, 2024.
- 発 行
- 2024年3月
- 要 旨
- The authors previously developed an intermediate evaluation index for transfer characteristics of the structural system of the completed vehicle to enhance the sound quality of combustion noise. Based on the results, a method was developed to obtain an index for the power unit similar to the above intermediate evaluation index by a shaker test on a stationary power plant. It was found that this shaker test and transfer characteristics evaluation method can approximately estimate the frequency band in which the structural system amplifies half-order components of the combustion noise related to sound-quality deterioration without conducting an actual engine operation test.
副室ジェット燃焼エンジンの高周波燃焼騒音発生メカニズム解析（第3報）
- 著 者
- 鳥居 建史、新谷 祐輔、木村 範孝、小林 広樹、小西 敬三
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol54, No.5, 2023.
- 発 行
- 2023年9月
- 要 旨
- This paper compares the characteristics of in-cylinder pressure measured in actual engines for various combustion modes and the characteristics of flame distribution and fuel reaction rate due to flame propagation calculated by CFD for those same modes, based on previous research. Results show that the significant increase in high-frequency in-cylinder pressure oscillation in pre-chamber jet combustion is due to two factors: a high in-cylinder pressure rise rate that is 2 to 3 times higher than in conventional spark ignition combustion, and an asymmetrical flame distribution caused by differences in fuel reaction rate of jet flames ejected from multiple nozzles of the pre-chamber.
副室ジェット燃焼エンジンの高周波燃焼騒音発生メカニズム解析（第2報）
- 著 者
- 小西 敬三、鳥居 建史、木村 範孝、小林 広樹、岡田 大輔
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol54, No.5, 2023.
- 発 行
- 2023年8月
- 要 旨
- 本論文では、副室ジェット燃焼エンジンに特有の7～10 kHz帯の燃焼騒音の大きさを定量的に評価するため、筒内圧力振動の評価手法を開発した。この手法では、クランク角歴400サイクル分の筒内圧力を測定し、燃焼室共鳴帯域における圧力振動のpeak-to-peak振幅をバンドパスフィルタでサイクルごとに算出する。その後、peak-to-peak振幅を平均することで、エンジン放射音を測定せずに高周波燃焼騒音を間接的に評価可能な筒内圧力振動の評価指標を得る。結果として、副室ジェット燃焼エンジンにおける高周波圧力振動は従来の火花点火燃焼エンジンの16倍であり、単一の筒内圧力センサで評価できることが示された。
副室ジェット燃焼エンジンの高周波燃焼騒音発生メカニズム解析
- 著 者
- 鳥居 建史、木村 範孝、小林 広樹、小林 裕幸、小西 敬三
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol54, No.1, 2023.
- 発 行
- 2023年1月
- 要 旨
- 急速燃焼を実現することで熱効率を向上させる副室ジェット燃焼ガソリンエンジンの開発において、6～9 kHz帯の高周波燃焼騒音の増加が課題となっている。このような燃焼騒音は、ガソリンエンジンではなくディーゼルエンジンの開発で問題となることが多く、燃焼室内の音響共鳴によって生じることが知られている。そこで、本エンジンの燃焼室の共鳴モードを有限要素モデルを用いた計算と実験的モード解析によって分析した。その結果、燃焼室容積の変化に伴って発生する共鳴周波数の変化が、前述の燃焼騒音の原因となる筒内圧力の特性に影響を与えることが明らかになった。
エンジン燃焼騒音の変動感を低減するための構造系伝達特性の中間指標
- 著 者
- 鳥居 建史、小西 敬三
- 収 録
- Transaction of Society of Automotive Engineers of Japan Vol54, No.1, 2023.
- 発 行
- 2022年12月
- 要 旨
- An order-based structural response function was developed as a simple intermediate index that indicates the quality of transmission characteristics when taking measures regarding transmission systems in order to enhance combustion noise quality. The index is the sum of the structural response functions from each cylinder for each typical order component, taking into account the different combustion timing of each cylinder. This enables identification of frequencies at which combustion noise is likely to be generated for each order. Comparison of the actual order-based structural response function and combustion noise showed that combustion noise quality deteriorates in frequency bands with high response amplitudes across multiple order components of the function. The results demonstrated that the function can be a useful intermediate index for structural measures.
Modal Analysis of Combustion Chamber Acoustic Resonance to Reduce High-Frequency Combustion Noise in Pre-Chamber Jet Ignition Combustion Engines
- 著 者
- Kenji Torii, Noritaka Kimura, Hiroki Kobayashi, Hiroyuki Kobayashi, Keizo Konishi
- 収 録
- SAE International Journal of Engines, No.17, 2024.
- 発 行
- 2024年1月
- 要 旨
- The notable increase in combustion noise in the 7–10 kHz band has become an issue in the development of pre-chamber jet ignition combustion gasoline engines that aim for enhanced thermal efficiency. Combustion noise in such a high-frequency band is often an issue in diesel engine development and is known to be due to resonance in the combustion chamber. However, there are few cases of it becoming a serious issue in gasoline engines, and effective countermeasures have not been established. The authors therefore decided to elucidate the mechanism of high-frequency combustion noise generation specific to this engine, and to investigate effective countermeasures. As the first step, in order to analyze the combustion chamber resonance modes of this engine in detail, calculation analysis using a finite element model and experimental modal analysis using an acoustic excitation speaker were conducted. As a result, it was found that there are two combustion chamber resonance modes in the 7–10 kHz band, both of which affect the high-frequency oscillation of the in-cylinder pressure. Both resonant modes have mode shapes that form a single nodal plane in the diametrical direction including the central axis of the cylinder, but the orientations of those nodal planes differ by 90 degrees. In addition, the two resonance frequencies are influenced by not only the bore diameter, temperature, and heat capacity ratio, but also the spatial shape of the combustion chamber. Therefore, when the piston descends and the spatial shape of the combustion chamber changes, the resonance frequencies change as well.