• Title/Summary/Keyword: Moment of Engine Inertia

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A Study on the Response Performances under Transient Operating Conditions in a Turlblocharged Diesel Engine (터보과급 디젤기관의 과도운전시 응답성능에 관한 연구)

  • 최낙정;이창식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.8
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    • pp.1575-1582
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    • 1992
  • This study describes the response performances of actual engine speed, turbocharger speed, air mass flow rate through engine, boost pressure ratio, exhaust temperature and combustion efficiency for a six-cylinder four-stroke turbocharged diesel engine during the change in operating conditions by using the computer simulation with test bed. In order to obtain the transient conditions, a suddenly large load was applied to the simulation engine with the several kinds of inertia moment in turbocharger and engine, and engine set speed. From the results of this study, the following conclusions were summarized The inferior response performances was mainly caused by turbocharger lag, and air mass flow rate and boost pressure ratio were closely related to the turbocharger speed. A reduced moment of turbocharger inertia resulted in less transient speed drop and much faster recovery to the steady state of the engine. The increase of moment of engine inertia reduced cyclic variation of engine speed. When a large load was applied to the engine at high speed, the engine could be fastly recovered. However, when the same load was applied to the engine at low speed, the engine was stalled.

Measurement of Inertia of Turbocharger Rotor in a Passenger Vehicle (승용차용 터보과급기 로터의 관성모멘트 측정)

  • Chung, Jin Eun;Lee, Sangwoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.1
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    • pp.33-38
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    • 2016
  • The turbocharger is an essential component to realize the engine down-sizing. The moment of inertia of turbocharger rotor is an important parameter with respect to acceleration performance of the vehicle. It can be calculated from the CAD software based the geometry data and the material properties. But the accurate value of the inertia of turbocharger rotor must be measured through the experimental method. In this study, the measurement of moment of inertia of turbocharger rotor for 2.0 L spark-ignition engine was carried out. First, an experimental equipment using a trifilar method was designed and fabricated. Some optical devices, that is, photo sensor, counter, convex lens, etc, were used to increase the accuracy of the measurement. Second, error sensitivity for the equipment was analyzed. The error of period time and the radius can give big affects to the accuracy of the moment of inertia. When the amount of error of these two were each 1.0 %, maximum error of the moment of inertia was under 3.0 %. Third, the calibration for the equipment was performed using a calibration rotor which has similar shape to turbine rotor but simple. Calculated value from CAD software and measured one for the calibration rotor were compared. The total error of the equipment and the measurement is about 1.3 %. This result shows that the equipment can give the good result with resonable accuracy. Finally the moment of inertia of the turbine rotor and compressor wheel were measured. The coefficient of variations, the ratio of standard deviation to mean value, were reasonably small at 0.57 % and 0.73 % respectively. Therefore this equipment is suitable for the measurement of the moment of inertia of the turbine rotor and compressor wheel.

A study on the viscous torsional vibration damper in a high speed diesel engine (고속디이젤 기관의 점성비틀림 진동댐퍼에 관한 연구)

  • 한영출
    • Journal of the korean Society of Automotive Engineers
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    • v.4 no.1
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    • pp.20-30
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    • 1982
  • Recent diesel engine has achieved high speed running comparable to that of gasoline engine as a speed improvement effort. Consequently, torsional vibration of high-speed diesel engine induced vibration nosise, reduced horsepower and the like. Viscous damper which is thought to be effective in curtailing the torsional vibration was studied over a wide range of speed. In this investigation, a water cooling, 4-cycle high-speed diesel engine(Msx. 3500 rpm)was used for the study. Theoretical analysis was made by assuming the engine to be an ideal equivalent system(length, moment of inertia) i. e. the multi-degree of freedom equivalent torsional vibration system with damper was analyzed. In the analysis, the inertia moment of suitable damper for this experiment was calculated by varying the relative damping coefficient of damper of engine for each damper. Furthermore, in the torsional vibration experiment, the torsional vibration amplitude of the crankshaft system was measured when the engine was equipped with dampers of different moments of inertia and also when the engine was equipped without dampers. The experimental results were compared with the analytical values and were found to be satisfied. The results of this investigation are summarized below; (1) It was found that for the engine equipped with dampers, the torsional vibration amplitude was reduced to about one third of those without dampers. (2) The optimum value of inertia moment of viscous damper for the engine was found to be about Id=1.05(kg.cm.s$^{2}$) (3) The optimum damping coefficient and the ratio of moment of inertia for the engine were found to be about Ca= 850(kg.cm.s), Rd=0.509, respectively (b1 dapmper).

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Effects of Design Parameters on Rattle Noise in a Direct Engine-PTO Driveline of Tractors (엔진 직결식 PTO 전동 라인의 주요 설계 변수가 PTO 변속부의 치타음에 미치는 영향)

  • Park Y.J.;Kim K.U.
    • Journal of Biosystems Engineering
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    • v.31 no.4 s.117
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    • pp.323-333
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    • 2006
  • Introduction of a direct engine-PTO driveline to agricultural tractors has reduced production cost and increased transmission efficiency of the PTO driveline. However, this type of PTO driveline has caused a severe rattle noise in the PTO gearbox under idle conditions. This study was conducted to investigate the causes of the rattle noise and the effects of driveline parameters on it. A mathematical model was developed for a direct engine-PTO driveline. The model was proved experimentally to be accurate enough to simulate the dynamic characteristics of the PTO driveline motions. The simulation study showed that the rattle noise was caused by collisions between the driving and driven gears in the PTO gearbox due to velocity variation of the gears, which was induced by torque fluctuations from the engine. It was also found that the rattle noise decreased with the drag torque and mass moment of inertia of the engine flywheel. Smaller mass moment of inertia of the driven gears and backlash also reduced the rattle noise. However, increasing the drag torque and mass moment of the engine flywheel or decreasing the backlash and mass moment of inertia of the driven gears were limited practically by their detrimental effects on transmission efficiency, gear strength and smooth meshing of the gears.

An Experimental Study of Engine Mount Optimization to Improve Noise and Vibration Quality of F.R. Vehicle (후륜구동 차량의 소음 진동 성능향상을 위한 엔진마운트 최적설계에 관한 실험적 연구)

  • 이준용;김찬묵
    • Journal of KSNVE
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    • v.7 no.4
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    • pp.681-688
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    • 1997
  • The purpose of engine mount system is to reduce the noise and vibration caused by engine vibration, and to decouple the roll and bounce mode at idle. To reduce the noise and vibration level in a vehicle, it is important to make the design optimization of engine mount system that consider the moment of inertia and inclination of mount rubber. As a result, according to the definition of Torque Roll Axis (TRA), the vibration axis at idle must be on the TRA or very close to it. In this paper, we studied the effect of the design optimization of engine mount system. And we have achieved good improvements in noise and vibration quality of F.R. vehicle.

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An Experimental Study of the Improvement of Driveability in Vehicle Acceleration Mode (차량 급가속시 운전성 개선을 위한 실험적 연구)

  • 송해박;최윤준;이종화;조한승;조남효
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.65-75
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    • 2001
  • Modern vehicles require a high degree of refinement including good driveability. Vehicle driveability, which becomes a key decisive factor f3r marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes experimental procedures which have been developed to measure engine torque and investigate shuffle characteristics. To analyze the vehicle dynamic behavior, fractional torques and inertia mass moment of engine, and drive train were measured. Shuffle characteristics during tip-in condition were investigated in an experimental vehicle at 2nd and 3rd gear stages. It was found that the shuffle characteristics were caused by sudden changes of engine torque and have a different vibration frequency with gear stage variation. Inertia mass moment of engine including flywheel rotation showed a key factor for the shuffle characteristics.

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A Study of the Control Logic Development of Driveability Improvement in Vehicle Acceleration Mode (차량 급가속시 운전성 향상을 위한 제어로직 개선에 관한 연구)

  • 최윤준;송해박;이종화;조한승;조남효
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.101-116
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    • 2002
  • Modern vehicles require a high degree of refinement, including good driveability to meet customer demands. Vehicle driveability, which becomes a key decisive factor for marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore, Engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes analysis procedures using a mathematical model which has been developed to simulate spark timing control logic. Inertia mass moment, stiffness and damping coefficient of engine and drive train were simulated to analyze the effect of parameters which were related vehicle dynamic behavior. Inertia mass moment of engine and stiffness of drive line were shown key factors for the shuffle characteristics. It was found that torque increase rate, torque reduction rate and torque recovery timing and rate influenced the shuffle characteristics at the tip-in condition for the given system in this study.

Element Design of Balancing Shaft for Reducing the Vibration in Engine Module (엔진진동 저감을 위한 밸런싱샤프트의 요소설계 기법 연구)

  • Kim, Chan-Jung;Beak, Gyoung-Won;Lee, Bong-Hyun;Kim, Gi-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.615-620
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    • 2005
  • Vibration in Engine module could be reduced by introducing a balance shaft module which has one or more unbalanced rotors. The unbalanced rotor is unbalanced in one direction that act as a opposite direction of the inertia force or moment triggered by engine component so that the largest order factor in vibration is efficiently decreased The ability of balance shaft to reduce the order element of engine component is investigated by a vehicle testing that is focused on comparing the vibration with balance shaft to that of without balance shaft. One of the commonly adapted balance shaft is tested by modal scheme for indemnifying the dynamic characteristics and an, the modal information is used for a clue to design the balance shaft module. The essential equation deriving the design parameters of unbalanced rotor is also presented for two cases, 3 in-ling and 4 in-ling cylinder model. Finally, the overall design process is explained with flow chart.

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Vibration Analysis of In-line Three Cylinder Engine with Balance Shaft Using DADS (DADS를 이용한 밸런스 샤프트 장착 직렬 3기통 엔진의 진동 해석)

  • 서권희;민한기;천인범
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.1
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    • pp.148-156
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    • 2000
  • For the in-line three cylinder engine whose crankshaft has a phase of 120 degrees, the total sum of unbalanced inertia forces occurring in each cylinder will be counterbalanced among three cylinders. However, parts of inertia forces generated at the No.1 and No.3 cylinders will cause a primary moment about the No.2 cylinder. In order to eliminate this out-of-balance moment, a single balance shaft has been attached to the cylinder block so that the engine durability and riding comfort may be further improved. Accordingly, the forced vibration analysis of the in-line three cylinder engine must be implemented to meet the required targets at an early design stage. In this paper, a method to reduce noise and vibration in the 800cc, in-line three cylinder LPG engine is suggested using the multibody dynamic simulation. The static and dynamic balances of the in-line three cylinder engine are investigated analytically. The multibody dynamic model of the in-line three cylinder engine is developed where the inertia properties of connecting rod, crankshaft, and balance shaft are extracted from their FE-models. The combustion pressure within the No.1 cylinder in three significant operating conditions(1500rpm-full load, 4000rpm-full load and 7000rpm-no load)is measured from the actual tests to excite the engine. The vibration velocities at three engine mounts with and without balance shaft are evaluated through the forced vibration analysis. Obviously, it is shown that the vibration of the in-line three cylinder engine with balance shaft is reduced to the acceptable level .

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A Study on the Optimization of the Torsional Vibration Using DFFSS Method for DI Diesel Engine (직접분사방식 디젤엔진의 6시그마 기법을 적용한 비틀림 최적화에 대한 연구)

  • Kim, Jang-Su;Koh, Jang-Joo;Lee, Chi-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.15 no.1
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    • pp.13-19
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    • 2012
  • Due to a low stiffness of cranktrain and a failure experience from a history within short development time, a viscous torsional vibration damper was applied in order to reduce the torsional vibration and keep the high reliability for the durability of cranktrain system in the direct injection diesel engine. As an improvement of the crankshaft stiffness by increasing the diameter of main and pin journal, a rubber type damper could be considered. In this study, the control factors of rubber damper, the moment of inertia ring, stiffness of damper and damping coefficient of ring, were investigated by DFSS method through the analysis work and the measurement in the real engine condition.