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Engine Mount Snubber의 실내소음에 미치는 영향에 관한 연구
선정욱(Jungwoog Sun),김광욱(Kwangwook Kim),임종태(Jongtae Lim),고찬희(Chanhee Ko),김영호(Youngho Kim),김인동(Indong Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
This paper is looking for interior noise contribution of engine mount snubber shape. Mount snubber is very important for durability. Furthermore, it has not been concerned about NVH performance according to snubber shape. Actually, engine mount snubber is contacting with mount bracket. We conduct several kinds of test to look over how mount snubber can effect on interior noise. Snubber shape and gap between snubber and mount bracket can deteriorate interior noise booming and sound quality as well. The smaller snubber shape, the better interior noise we got. However, still we need snubber due to durability. Therefore, we need to optimize snubber shape for both durability and NVH performance. It means it is necessary to compromise between them during the engine mount snubber design stage.
선정욱(Jungwoog Sun),우성근(Sunggeun Woo),황태진(Taejin Hwang),이병로(Byoungro Lee) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11
Sometimes vehicle has severe firing order booming noise at high rpm. Normally, it is caused by powertrain excitation source due to high mechanical input force. So, we could think high rpm booming noise is caused by structure borne noise through the engine mounts or cradle. However, engine acoustic radiation noise also could be a main contributor to the booming noise. This study deals with experimental assessment of “air-borne” high rpm booming noise. First step is structureborne portion define. Through the transfer path analysis for all engine mounts and decouple test, we can conclude that structure-borne portion is very small. Second step is to define air-borne path. When we reduce engine radiation noise, booming noise is improved as well. Interior cabin wise, acoustic cavity mode at issued frequency is defined. Panel contribution analysis shows windshield glass to drive ear path is most sensitive path. Some insulation treatment to block the path between windshield glass and drive ear, we can get the improvement as well. Therefore, this study shows how to access and define about “air-borne” high rpm booming noise through the experiments.
Analysis of hill road vibration for 3cylinder powertrain
Jungwoog Sun(선정욱),Namcheol Kim(김남철),Dalsik Kim(김달식),Byoungro Lee(이병로) 한국자동차공학회 2015 한국자동차공학회 학술대회 및 전시회 Vol.2015 No.11
At the hill road, during the launch, we can get the severe body vibration such as seat track, steering wheel and even interior noise. Especially for the 3cylinder, it could be worse than 4cylinder due to the 1<SUP>st</SUP> order imbalance. It means, in the case of 3cylinder, there are two kinds of sources, 1<SUP>st</SUP> and 1.5<SUP>th</SUP> orders. This study deals with assessment process for root cause. First step is to define the source - higher axle torque and imbalance level. Higher axle torque at the hill can make higher tractive road load and input force to the engine mount. Measured axle torque characteristic well matches with seat track vibration. Engine 1.5<SUP>th</SUP> order gas torque fluctuation at the hill is also much higher than at the flat road. Another source is 1st order imbalance which is 3cylinder specific issue. Second step is to look for the path – engine mount stiffness change and powertrain rigid body mode. Engine mount stiffness increased at the hill due to the higher axle torque. It can change powertrain rigid body mode at hill with stiffer engine mounts which can be increased up to max axle torque, or max input source. Additionally, through the 12DOF analysis using measured mount stiffness under the hill road condition, yaw mode at the hill is closed with issued frequency for the 1<SUP>st</SUP> order. So, powertrain rigid body mode could be one of the reason to increase the body vibration at the hill. Regarding body sensitivity, there is no changes even for the higher, almost double mount stiffness. However, it does not exactly reflect the hill road condition during the test. Further study is required. Therefore, source wise, we need to check the powertrain rigid body mode and higher gas torque fluctuation at hill. Path wise, we should check the engine mount stiffness change at the hill.
엔진 마운트의 interm 브라켓 공진 주파수 target 설정에 관한 연구
선정욱(Jungwoog Sun),우성근(Sunggeun Woo),전병근(Byounkeun Jeon),김달식(Dalsik Kim),강신남(Shinnam Kang) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.10
When developing engine mount, interm mount bracket 1st resonance is critical to make sound quality better or worse. So, at the initial stage of development, we need to consider some design parameter to setup the target of interm bracket 1st resonance. Especially, 3cylinder interm bracket guideline is not well known. So, this paper deals with some important sensitivity which should be considered during the development of vehicle. From source to interior side, we should know the component sensitivity like body sensitivity p/F or bracket gain etc. Through this paper, we could get the knowledge of design guideline and key consideration points.
Lockup Vibration 평가를 위한 A/T 해석 및 검증
이상윤(Sangyun Lee),선정욱(Jungwoog Sun),김용석(Yongsuk Kim) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
This paper describes a procedure to remove lockup vibration when TCC(Torque Convertor Clutch) applied at lower rpm for improving fuel economy. A/T(Acceleration/Torque) analysis must be done in a beginning of architecture development for estimating lockup vibration and providing solution. Because frequency range of lockup vibration is low frequency range, 30~40Hz, and it never be fixed in a hardware stage. A/T analysis is very essential to check lockup vibration problem in an early stage and provide solution before hardware release. A/T sensitivity magnitude and peak location was verified through hardware test. Effectiveness of target for A/T sensitivity was also verified with checking the subjective feeling of lockup condition.