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Effect of Inlet and Exhaust Pressures on the Scavenging Characteristics of a Carbureted Uniflow Scavenged Engine
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Abstract
The effect of inlet and exhaust manifold pressures on the scavenging and fluid flow inside a turbocharged, carbureted, uniflow scavenged two-stroke engine has been studied numerically. An axisymmetric computational code, CARE, has been used for the purpose. The inlet pressure is varied between 0.25 MPa and 0.29 MPa, keeping exhaust pressure constant at 0.23904 MPa, to study the effect of inlet pressure. Similarly, the exhaust pressure is varied between 0.2 MPa and 0.25 MPa, keeping inlet pressure constant at 0.26104 MPa. The results are plotted in the form of velocity vector plots, fresh charge concentration contours and swirl velocity contours to illustrate the flow field at various crank angles. The global quantities, viz., the cylinder pressure, total mass of gases in the cylinder, fresh charge and residual gas masses in the cylinder during scavenging are plotted as functions of crank angle, for various values of the inlet and exhaust pressures. The various gas exchange efficiencies are also plotted as functions of the inlet and exhaust pressures. The results obtained indicate that the inlet-to-exhaust pressure difference governs the mass flow rate across the inlet and the exhaust ports, and the velocity of the gases at the inlet and the exhaust have a strong influence on the flow field and scavenging. The delivery ratio is higher for a larger inlet-to- exhaust pressure difference, giving rise to better scavenging and charging, and inferior trapping.
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Authors
Citation
Ravi, M. and Marathe, A., "Effect of Inlet and Exhaust Pressures on the Scavenging Characteristics of a Carbureted Uniflow Scavenged Engine," SAE Technical Paper 920840, 1992, https://doi.org/10.4271/920840.Also In
References
- Uzkan, T. ‘An analysis of the engine blow-down process using multidimensional computations’ Trans. ASME. J. Engg. Gas Turbines and Power 109 4 459 464 October 1987
- Uzkan, T. Hazelton, J.R. ‘The influence of swirl on the fresh charge stratification in an I.C. engine combustion chamber’ SAE paper no. 860466 1986
- Uzkan, T. ‘Analytically predicted effects of engine stroke on the scavenging characteristics of a uniflow two-stroke cycle engine’ On Flows in Internal Combustion Engines - IV Uzkan, T. ASME - FED 65 67 73 1988
- Uzkan, T. ‘The effects of engine speed on the scavenging characteristics of a two-cycle engine’ Trans. ASME. J. Engg. Gas Turbines and Power 110 3 523 530 July 1988
- Diwakar, R. ‘Multidimensional modelling of the gas exchange processes in a uniflow scavenged two-stroke diesel engine’ International Symposium on Flows in I.C. Engines III FED 28 Uzkan, T. Tiederman, W.G. Novak, J.M. 1985
- Diwakar, R. ‘Three-dimensional modelling of the in-cylinder gas exchange processes in a uniflow scavenged two-stroke engine’ SAE paper no. 870596 1987
- Ravi, M.R. Marathe, A.G. ‘On the importance of periodically repeating pressure histories to the gas exchange characteristics of a unilflow scavenged carbureted engine’ ASME Energy Sources Technology Conference (ESTC-92) January 1992
- Ravi, M.R. ‘Multidimensional modelling of uniflow scavenging in two-stroke engines’ Indian Institute of Science Bangalore, India 1991
- Ravi, M.R. Marathe, A.G. ‘Multidimensional modelling of uniflow scavenging in two-stroke reciprocating piston engines’ Moving Boundaries - '91 , First International Conference on Free and Moving Boundary Problems Southampton, U.K. July 2-4 1991
- Ravi, M.R. Marathe, A.G. ‘Effect of port sizes and timings on the scavenging characteristics of a uniflow scavenged engine’ SAE International Congress and Exposition Detroit Feb. 24-28 1992
- Patankar, S.V. Numerical Heat Transfer and Fluid Flow Hemisphere Publishing Co. 1980