Modeling the Effects of Intake Flow Structures on Fuel/Air Mixing in a Direct-injected Spark-Ignition Engine 961192
Multidimensional computations were carried out to simulate the in-cylinder fuel/air mixing process of a direct-injection spark-ignition engine using a modified version of the KIVA-3 code. A hollow cone spray was modeled using a Lagrangian stochastic approach with an empirical initial atomization treatment which is based on experimental data. Improved Spalding-type evaporation and drag models were used to calculate drop vaporization and drop dynamic drag. Spray/wall impingement hydrodynamics was accounted for by using a phenomenological model. Intake flows were computed using a simple approach in which a prescribed velocity profile is specified at the two intake valve openings. This allowed three intake flow patterns, namely, swirl, tumble and non-tumble, to be considered. It was shown that fuel vaporization was completed at the end of compression stroke with early injection timing under the chosen engine operating conditions. The mixing process and the in-cylinder fuel distribution were found to be significantly affected by the flow structures which are dominated by the intake flow details. More uniform distributions of air-fuel ratio and mixture temperature in the combustion chamber were obtained at the end of compression in the cases using tumble and swirl flow patterns.
Citation: Han, Z., Reitz, R., Claybaker, P., Rutland, C. et al., "Modeling the Effects of Intake Flow Structures on Fuel/Air Mixing in a Direct-injected Spark-Ignition Engine," SAE Technical Paper 961192, 1996, https://doi.org/10.4271/961192. Download Citation
Zhiyu Han, Rolf D. Reitz, Peter J. Claybaker, Christopher J. Rutland, Jialin Yang, Richard W. Anderson
University of Wisconsin-Madison, Ford Motor Co
International Fuels & Lubricants Meeting & Exposition
Modeling Techniques in SI and Ci Engines-SP-1178, SAE 1996 Transactions - Journal of Fuels and Lubricants-V105-4