• 한국음향학회지
• /
• 제35권3호
• /
• pp.208-215
• /
• 2016

엔진 연소 거동을 제어 및 개선하기 위하여, 연소실 내의 압력에 대한 다양한 연구가 지속적으로 수행되고 있다. 이 논문에서는 연소실 내의 압력을 통하여 디젤엔진의 연소음 레벨을 추정하였으며 이를 연소음 지수라고 정의하였다. 연소음 지수는 연소실 내의 압력신호를 고속 푸리에 변환을 통하여 계산하였으며 그 유효성을 검증하였다. 검증된 연소음 지수를 기반으로 한 제어기가 개발되었으며 차량에 탑재하였다. 연소음 지수의 목표 값을 만족시키기 위하여 일부의 분사변수를 제어하였으며 차량 연소음이 특정 주파수 영역에서 4.0 dB(A)까지 개선되었다.

• 한국소음진동공학회논문집
• /
• 제21권10호
• /
• pp.883-889
• /
• 2011

The brand sound of vehicle diesel engine is recently one of the important advantage strategies in the automotive company. Because various noise components masked under high frequency level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on vehicle sounds and noises. In particular, the interior sound quality has been one of research fields that can give high quality feature to vehicle products. Vehicle interior noise above 500 Hz is usually controlled by sound package parts. The materials and geometries of sound package parts directly affect on this high frequency noise. This paper describes the sound quality evaluation method for the vehicle diesel engine noise to establish objective criteria for sound quality assessment. Considering the sensitivity of human hearing to impulsive sounds such as diesel noise, the human auditory mechanism was simulated by introducing temporal masking in the time domain. Furthermore, each of the human auditory organs was simulated by computer codes, providing reasonable analytical explanations of typical human hearing responses to diesel noise. This method finally provides the sound quality index of vehicle diesel engine noise that includes high frequency intermittent offensive sounds caused by impacting excitations of combustion and piston slap.

• 한국소음진동공학회논문집
• /
• 제23권10호
• /
• pp.902-908
• /
• 2013

The input torque ripple induced by combustion engines is a significant source of NVH(noise, vibration and harshness) problem in automotive transmissions. Because this torque fluctuation is primarily transmitted to the input shaft of automotive powertrains(e.g., automatic transmissions) when the lock-up clutches are closed, a torsional damper with helical springs is generally inserted between engine and transmissions to isolate the input vibratory energy, which is essential for the passenger comfort. The torsional vibration isolator exhibits frequency ranges in which there is low vibration transmissibility. However, the isolation performance is currently evaluated through the static torsional spring characteristics. In this study, the transmissibility of torsional spring dampers, essential dynamic performance index for vibration isolator, is first experimentally evaluated.