• Journal of Advanced Marine Engineering and Technology
• /
• 제22권1호
• /
• pp.77-84
• /
• 1998

Based on experimental analysis, the characteristics of pulsating pressure wave propagation is clarified by testing of 4-stroke gasoline engine. The pulsating pressure wave in exhaust system is generated by pulsating gas flow due to working of exhaust valve. The pulsating pressure wave is closely concerned to the loss of engine power according to back pressure and exhaust noise. It is difficult to exactly calculate pulsating pressure wave propagation in exhaust system because of nonlinear effect. Therefore, in the first step for solving these problems, this paper contains experimental model and analysis method which are applied two-port network analysis. Also, it shows coherence function, frequency response function, back pressure, and gradient of temperature in exhaust system.

• 한국자동차공학회논문집
• /
• 제4권4호
• /
• pp.18-26
• /
• 1996

Based on experimental analysis, the characteristics of pulsating pressure wave propagation is clarified by testing of 4-stroke gasoline engine. The pulsating pressure wave in exhaust system is generated by pulsating gas flow due to working of exhaust valve. The pulsating pressure wave is closely concerned to the loss of engine power according to back pressure and exhaust noise. It is difficult to exactly calculate pulsating pressure wave propagation in exhaust system because of nonlinear effect. Therefore, in the first step for solving these problems, this paper contains experimental model and analysis method which are applied two-port network analysis. Also, it shows coherence function, frequency response function, back pressure, and gradient of temperature in exhaust system.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1996년도 춘계학술대회 논문집
• /
• pp.72-78
• /
• 1996

Based on experimental analysis, the characteristics of pulsating pressure wave propagation is clarified by testing of 4-stroke gasoline engine. The pulsating pressure wave in exhaust system is generated gyulsating gas flow due the working of exhaust valve. The pulsating pressure wave is closely concerned to the loss of engine power according to back pressure and exhaust noise. It is difficult to exactly calculate pulsating pressure wave nonlinear effect. Therefore, in the first step for solving these problems, this paper contains experimental model and analysis method which are applied two-port network analysis. Also, it shows coherence function, frequency response function. back pressure, and gradient of temperature in exhaust system.

• 동력기계공학회지
• /
• 제10권3호
• /
• pp.11-16
• /
• 2006

The pressure fluctuation in the intake and exhaust pipe of 4 stroke-cycle diesel engine is caused by reciprocating motion of piston for suction of fresh air and exhaust of burned gas. this gas dynamic effect can be utilized for increase the volumetric efficiency. Many empirical studies have been carried out to investigate the effects of intake pulsating flow on the volumetric efficiency. However, when the gas dynamic effects are utilized for the variable speed engine to increase its performance, The speed range in which the maximum volumetric efficiency is limited and there occurs some difficulties in lay-out of intake system because it become too long. During induction process, as waves travel both directions, they are reflected and interacted each other and pressure waves are transmitted through it. Hence, the flow becomes more complex and unsteady flow. These pressure waves act upon intake pulsating flow and affects on the volumetric efficiency. In this paper the effects of pulsating flow of intake and exhaust pipes on volumetric efficiency were examined and evaluated. It was found that volumetric efficiency was affected by pulsating flow of intake and exhaust pipes.

• 대한기계학회논문집
• /
• 제11권5호
• /
• pp.846-855
• /
• 1987

본 연구에서는 실용적 설계및 이론해석에 필요한 동적 거동에 관한 현상규명 및 기초자료를 제공하기위해, 기하학적 형상변화에 따른 맥동연소의 안정성 및 흡입공 기량의 측정을 통한당량비의 범위를 관찰하고, 연소실과 배기관, 공기유입관, 연료노 즐실에서의 압력을 각각 동시측정해서 동적거동에 관해 고찰하고, 작동주파수에 관한 간단한 실험식의 확립과 추력성능에 관한 실험을 행했다.

• 한국자동차공학회논문집
• /
• 제15권4호
• /
• pp.108-114
• /
• 2007

This research represents the catalytic converter for application in the motorcycle. We have to consider about catalytic converter for reducing exhaust gas strength regarding the displacement volume enlargement. The catalytic converter has been widely used to satisfy the regulations of pollutant emissions from automobiles. Recently, all catalytic converter researches are about automobile. Study about motorcycle catalytic converter has not been conducted yet. In this study, flow uniformity and pressure distribution were simulated in the monolithic inlet of catalytic converter for motorcycle. Exhaust pulsation pressure was set as transient condition about. It was found that flow uniformity shown in base model (0.85) was lower than megaphone model (0.98).

• 한국자동차공학회논문집
• /
• 제8권4호
• /
• pp.85-92
• /
• 2000

The pulsating pressure waves are composed of fundamental frequency and higher order harmonics in exhaust pipe of engines. The nonlinearity in exhaust pipe is caused by their interactions. The error which is between prediction and measurement is induced by the nonlinearity. We can not explain this phenomenon using linear acoustic theory which is existing theory. So power spectrum which was used in linear theory is not useful. Bispectrum and bicoherence functions which are a higher order spectrum are applicable to explain this phenomenon. This paper proposes a nonlinear effect of pulsating pressure waves. The phenomenon proposed here is identified by using of higher order spectrum density functions.

• 한국생산제조학회지
• /
• 제21권2호
• /
• pp.196-201
• /
• 2012

This study represents numerical study on the thermal and fluid flow characteristics of exhaust gas in a motorcycle muffler. The engine generates 125cc of displacement. Numerical analysis with computational fluid dynamics(CFD) was carried out to investigate the exhaust gas that flow into a motorcycle muffler. The STAR-CD S/W used to analyze three dimensional steady state and transient in a muffler. The Navier-Stokes Equation is solved with SAMPLE and PISO method in cartesian coordinates system. As the numerical result, it could be confirmed pulsating pressure generated from inlet of muffler become closer to the atmospheric pressure through baffle. Also the numerical result was almost identical to experimental result and, through the comparison, the reliability of numerical result was confirmed.