차량용 터보차져 흡기 유동음 최적 개선

박호일(Hoil Park),최성배(Sungbae Choi),장성식(Seongsik Jang),황준영(Junyoung Hwang) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4

There are several flow noises induced from compressors of automotive turbochargers. In the previous study, the flow noise was analyzed to be around 1.6k~1.8kHz from gasbench tests, and could be reduced by machining a proper rectangular groove around compressor inlet before its main blades. The groove was shown to be very effective for removing the noise under the small difference of compressor performance. It was all right because the engine performance was high enough to cover the difference. This study was interested in another flow noise, rather the higher and wider frequency band, 4k~6kHz ? the 3<SUP>rd</SUP> order of turbocharger speed, and proposed an optimal configuration of the groove, lowering the noise and maintaining the performance. A best shape was proposed, and was confirmed to be satisfied with the performance on an engine dynamometer and the noise target on a vehicle.

터보차져 운전모드에 따른 소음맵 비교

박호일(Hoil Park),엄상봉(Sangbong Eom),황준영(Junyoung Hwang),윤태진(Taejin Yoon) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

A noise map has been developed for globally analyzing special noises radiating from automotive turbochargers. This map could be obtained by replacing the efficiency with noise data in a compressor performance map. The characteristics of a special noise could be easily understood from it since the noise distribution was shown on their operating area. Turbochargers were generally operated under constant speeds for measuring their performance. This paper compared two additional operation modes to the constant speed for the noise map. First, it was operated for almost constant volumetric flow rates in a compressor. Second, it was done for constant pressure ratios. In addition, it was investigated how the maps would be changed by the different sweeping times of surge-to-choke at the constant speeds, 1/2 and 1/4 times of the reference period.

차량용 터보차져 흡기 유동음 개선

박호일(Hoil Park),서주봉(Jubong Seo),홍성유(Sungyou Hong),강수영(Suyoung Kang),김장균(Janggyeun Kim) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

A flow noise radiating from a compressor housing of a vehicle turbocharge was investigated. The noise was induced by a vortex around the intake area of the compressor wheels - a intake flow noise, realized to be largely affected by a combination of the shape of the compressor scroll and that of compressor wheels by tests. And, its frequency did not increase proportionally to the turbocharger speed, and was located around the range of 1.6㎑ and 1.8㎑ to the whole working area of the turbocharger. Some countermeasures were tried to reduce the noise - helmholtz resonators, the change of the diffuser, the smaller compressor scroll, and a groove around the intake area of the compressor wheels. The smaller compressor scroll could effectively reduced the noise, but was not adopted because of the deterioration of the compressor performance. For the noise reduction, the groove was chosen because it could sufficiently reduce the noise and maintain the performance.

모터링 내구시험을 상사한 비정상 온도이력을 받고 있는 엔진 터보차져의 열적 거동해석

최복록(Boklok Choi),방인완(Inwan Bang),장훈(Hoon Chang) 한국자동차공학회 2011 한국 자동차공학회논문집 Vol.19 No.6

Fatigue cracks of the turbocharger are often observed for high performance engines under thermal shock tests. Maximum exhaust gas temperature of recently developed gasoline engines could reach approximately 950℃. It's very important to estimate transient temperature histories during thermal shock cycles to predict the stress and the fatigue life of the turbocharger. With these temperature profiles, temperature-dependent material properties and boundary conditions, we could identify critical locations by the application of finite element simulation technologies. In this paper, we applied the reliable analysis approach to the actual turbocharger to predict the weak locations due to the repetitions of plastic strains and compared the results with the crack locations under physical engine test.

터보차저의 축추력 예측을 위한 유한요소 모델 개발

이인범,최복록 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.3

The axial thrust acting on the turbocharger rotor is basically generated by the unbalance between turbine wheel gas forces and compressor wheel air forces. It has a significant influence on the friction losses, which reduces the overall efficiency and performance of high-speed turbocharger. Therefore, it’s important to calculate the thrust forces under operating conditions (surge, choke and etc.) in a turbocharger. The purpose of this paper is the development of numerical simulation methods which were verified by experimental results of axial thrust and thermally induced constraint tests of the turbocharger. The first FE model showed the relationship between thrust forces and strains by calculating the strains on specially designed thrust bearing and were compared with test results. And the second one is to identify the thermally induced strains in order to remove the thermal effects from measured strains. With these models, it’s possible to inversely predict the magnitudes of the axial thrust by directly measured strains and temperatures under operating turbocharger.

차량용 터보차져의 컴프레서 BPF 소음 저감

박호일(Hoil Park),임상봉(Sangbong Eom),서주봉(Jubong Seo),이승현(Seunghyun Lee) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.4

Automotive turbochargers have become common in gasoline engines as well as diesel engines. They are excellent devices to effectively increase fuel efficiency and power of the engines, but they unfortunately cause several noise problems. The noises are classified into mechanical noises induced from movement of a rotating shaft and aerodynamic noises by air flow in turbochargers. The mechanical noises are whine and howling noises, and the aerodynamic noises are BPF (blade-passing frequency), pulsation, surge, some special frequency noises. These noises are bothering passengers because their levels are higher or their frequencies are clearly separated from engine or vehicle noises. The noise investigated in this paper is a BPF noise induced by compressor wheels, whose frequency is the multiplication of the number of compressor wheel blades and its rotational speed. The noise is strongly dependent upon the geometry of wheels and the number of blades. This study tried to apply a groove close to the inlet side of compressor wheels in order to reduce the BPF noise. The groove has successfully reduced the noise of narrow band frequency of a turbocharger. It shows that the groove could reduce the wide band frequency noise, the compressor BPF noise with a best shape of the groove.

차량용 터보차져의 소음도표 작성 및 응용

이형일(Lee, Hyeong-Il) 한국소음진동공학회 2010 한국소음진동공학회 논문집 Vol.20 No.5

A test facility which can simultaneously measure turbocharger operating condition variables and vibro-acoustic emission in the situations that are quite similar to real internal combustion engine operating conditions has been introduced. Using this facility, a new method sweeping from full open throttle to deep surge region along constant speed curves can be utilized instead of the stationary method that has been traditionally used to obtain turbocharger compressor maps. Data covering an extensive range of the compressor performance map have been collected and analyzed. An experimental study is performed to define a noise diagram that correlates vibro-acoustic measurements to aerothermodynamic operating conditions. An instrumentation set in the facility allows the automatic definition of the operating point on the turbine and compressor map of the turbocharger. Also, radiated sound pressure and casing vibration data corresponding to the point are obtained by a microphone in the vicinity of the compressor casing and an accelerometer on the casing. The major source(s) of noise at specific operating point on the map can be easily identified with these maps. Also, acoustic characteristics of a given turbocharger at the vicinity of the surge as well as in the surge are also defined. Finally, the possibility to define mild surge region of a turbocharger using vibro-acoustic measurements is studied.

터보차져를 이용한 연료전지 시스템의 효율 향상에 대한 수치 해석적 연구

김동규(Dongkyu Kim),서정훈(Jeonghoon Seo),김선엽(Seonyeob Kim),송한호(Hanho Song),김민수(Minsoo Kim) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

Parasitic power is a crucial factor in determining the total efficiency for pressurized fuel cell system. Generally, pressure is applied through compressor which consumes high power. This paper suggest novel system using turbocharger that has benefit in reducing compressor power. In order to investigate performance of this novel fuel cell system, steady state model of PEMFC system is developed adding turbocharger. The model is discretized into several part ? stack, membrane humidifier, compressor, thermal management system and extra device ? to resolve performance enhancement of the system. At first, the performance of simulation of general pressurized PEMFC system is analyzed in each model and whole integrated system. After that, novel system with turbocharger is analyzed in same process of that of general system. Finally, relations among whole parts are considered under various operating conditions. These results are useful to design the variable pressure PEMFC system model with turbocharger and find optimal operating condition under various current densities.

중형 엔진 터보차져의 원심압축기에 관한 공력학적 3차원 형상 및 구동용 연소기 설계

김홍원(Hong-Won Kim),류승협(Seung-Hyup Ryu),갈상학(Sang-Hak Ghal),하지수(Ji-Soo Ha),김승국(Seung-Kuk Kim) 한국유체기계학회 2005 유체기계 연구개발 발표회 논문집 Vol.- No.-

An aerodynamic design for centrifugal compressor which was applied to medium speed diesel engine has done. First of all, exact compressor specifications must be defined by accurate engine system matching. This matching program has been developed. Using the meanline prediction method, geometric design and performance curve for compressor was done and verified by comparing three dimensional viscous CFD results. The deviation at the design point was about 2.3%. Combustor has been designed and manufactured for the performance test of medium speed diesel engine turbocharger. Fuel nozzle of combustor was designed and performed by PIV and PDPA test equipment. Through these results, spray characteristics were studied and flow coefficient equation was deduced.

GT-Power를 이용한 터보 매칭 및 밸브 사양 선정에 대한 연구

김충식(Choongsik Kim),장원석(Wonseok Jang),정종화(Chonghwa Chung) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

Turbocharger application on spark ignition engines can provide the improved fuel economy by downsizing and the better fun-to-drive with higher engine torque as well. However, its development requires complicated balancing process of the trade-off between the targets and the constraints within limited development time and cost. So, it’s very important to select the best turbocharger design from the early phase of engine development and one-dimensional engine cycle simulations can help such early development process by defining engine design that leads to the best performance for the given constraints. In this study, candidate turbocharger maps were evaluated by using GT-Power in terms of engine performance within the limits of boost pressure, turbocharger speed, surge and choke characteristics. Also, high altitude engine performance and the transient response characteristics were factored in from the vehicle performance perspective. Finally, cam profile and valve timings were optimized with the selected turbocharger to define the best engine design that delivers better startability and full load performances with balanced part load fuel efficiencies.