A multidimensional computational fluid dynamics (CFD) tool has been applied to analyze the exhaust system of a gasoline engine. Since gas flow in the exhaust manifold is affected by exhaust pulsations, prediction methods based on steady flow are not able to predict gas flow precisely enough. Therefore, a new multidimensional calculation method, called pulsation flow calculation, has been developed. A one-dimensional gas exchange simulation and a three-dimensional exhaust gas flow calculation are combined to simulate gas flow pulsations caused by the gas exchange process. Predicted gas flow in the exhaust manifold agreed with the experimental data. With the aim of reducing emissions, the pulsation flow calculation method has been applied to improve lambda feedback control using an oxygen sensor. The factors governing sensor sensitivity to the exhaust gas from each cylinder were clarified. The possibility of selecting the oxygen sensor location in the exhaust manifold on the basis of calculations was proved. The effect of an exhaust manifold with equal-length cylinder runners on achieving uniform sensor sensitivities was made clear. In addition, a new lambda feedback control method for an exhaust manifold with different-length cylinder runners is proposed.

Aita, S., Tabbal, A., Munck, G., Fujiwara, K., Hongoh, H., Tamura, E., and Obana, S., 1990, “Numerical Simulation of Port-Valve-Cylinder Flow in Reciprocating Engines,” SAE Paper No. 900820.
Godrie, P., and Zellat, M., 1994, “Simulation of Flow Field Generated by Intake Port-Valve-Cylinder Configurations—Comparison with Measurements and Applications,” SAE Paper No. 940521.
Naitoh, K., Fujii, H., Urushihara, T., Takagi, Y., and Kuwahara, K., 1990, “Numerical Simulation of the Detailed Flow in Engine Ports and Cylinder,” SAE Paper No. 900256.
Trigui, N., Affes, H., and Kent, J. C., 1994, “Use of Experimentally Measured In-Cylinder Flow Field at IVC as Initial Conditions for CFD Simulation of Compression Stroke in I.C. Engine-A Feasibility Study,” SAE Paper No. 940280.
Khalighi, B., El Tahry, S. H., Haworth, D. C., and Huebler, M. S., 1995, “Computation and Measurement of Flow and Combustion in a Four-Valve Engine with Intake Variations,” SAE Paper No. 950287.
Kuo, T.-W., and Reuss, D. L., 1995, “Multidimensional Port-and-Cylinder Flow Calculations for the Transparent-Combustion-Chamber Engine,” Engine Modeling ICE-Vol. 23, ASME, New York.
Lai, M.-C., Kim, J.-Y., Cheng, C.-Y., Chui, G., and Pakko, J. D., 1991, “Three-Dimensional Simulations of Automotive Catalytic Converter Internal Flow,” SAE Paper No. 910200.
Wendland, D. W., Kreucher, J. E., and Andersen, E., 1995, “Reducing Catalytic Converter Pressure Loss with Enhanced Inlet-Header Diffusion,” SAE Paper No. 952398.
Kuo, T.-W., and Khalighi, B., 1995, “Numerical Study on Flow Distribution in T-Junctions and a Comparison With Experiment,” Engine Modeling, ICE-Vol. 23, ASME, New York.
Park, S.-B., Kim, H.-S., Cho, K.-M., and Kim, W.-T, 1998, “An Experimental and Computational Study of Flow Characteristics in Exhaust Manifold and CCC (Close-Coupled Catalyst),” SAE Paper No. 980128.
Cho, Y.-S., Kim, D.-S., Han, M., Joo, Y., Lee, J.-H., and Min, K.-D., 1998, “Flow Distribution in a Close-Coupled Catalytic Converter,” SAE Paper No. 982552.
Takeyama, S., Ishizawa, S., Yoshikawa, Y., and Takagi, Y., 1987, “Gas Exchange Simulation Model for Improving Charging Efficiency of 4-Valve Internal Combustion Engine,” I.M.E. the First Conference of the Computers in Engine Technology.
Hasegawa, Y., Akazaki, S., Komoriya, I., Maki, H., Nishimura, Y., and Hirota T., 1994, “Individual Cylinder Air-Fuel Ratio Feedback Control Using an Observer,” SAE Paper No. 940376.
STAR-CD Version 3.05 Manual, 1998, Computational Dynamics, Ltd.
, and
, “
Theoretical and Experimental Study on Combustion Similarity for Different Size Diesel Engines
, pp.
You do not currently have access to this content.