haku: @supervisor Larmi, Martti / yhteensä: 54
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| Tekijä: | Rodriguez, Alvaro |
| Työn nimi: | Acoustic simulation of a tractor engine exhaust system |
| Julkaisutyyppi: | Diplomityö |
| Julkaisuvuosi: | 2013 |
| Sivut: | 68 Kieli: eng |
| Koulu/Laitos/Osasto: | Energiatekniikan laitos |
| Oppiaine: | Polttomoottoritekniikka (Kul-14) |
| Valvoja: | Larmi, Martti |
| Ohjaaja: | Kaario, Ossi |
| Sijainti: | P1 Ark Aalto 9850 | Arkisto |
| Avainsanat: | acoustic modelling noise emission exhaust system sound pressure level |
| Tiivistelmä (eng): | This thesis focuses on the acoustic simulation of an agricultural engine. Its aim was to modify the noise emissions of a tractor diesel engine by making parameter changes on the exhaust line. Research about acoustic emissions from engines and a suitable software tool, available to simulate acoustics of the exhaust line is also included. Noise legislation existing today for tractors does not present big challenge for tractors having a cabin so the principal goal for developing the acoustics in the present study focuses on satisfy driver comfort and customer demand. A simulation model of the VALTRA N-Series 4-stroke, 4-cylinder, 4.9L has been built taking into account the intake and exhaust system. Whole simulation was carried out by way of I-D fluid dynamics utilizing the software GT ·Power 7.3. The turbo model was scaled from a 3.5L engine due to the exact engine turbo map was not available. The tractor model was validated by means of experimental data measured along the intake and the exhaust system using high frequency pressure sensors and at the exhaust outlet utilizing a microphone. Elementary modifications like exhaust pipe diameter, length and bend variations were analysed. Furthermore the acoustic damping effect of the existing components in the exhaust pipe was determined and new components like resonators were included. Acoustical performance of the system is presented in terms of sound pressure level emitted by the exhaust outlet. The results of this study show that the importance of exhaust pipe design on noise emissions and how the model behaves to elementary changes. In particular exhaust pipe diameter has a critical influence on the acoustic emissions and it was the only parameter which produced significant variations at the low frequency range. |
| ED: | 2014-01-20 |
INSSI tietueen numero: 48359
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