Automation and Autonomous Systems

M. Suresh ¹, R. Hari Prakash ², B. Durga Prasad ³

Affiliations
1 Jawaharlal Nehru Technological University, Anatapur, IN
2 Birla Institute of Technology, Ranchi, IN
3 Department of Mechanical Engineering, JNTUA, Anantapur, IN

Abstract

Direct injection spark ignition (DISI) engines have a large potential to reduce emissions and specific fuel consumption. One of the most important problems in the design of DISI engines is the cycle-to-cycle variations of theflow, mixing and combustion processes. The Large Eddy Simulation (LES) based analysis is used to characterize the cycle-to-cycle fluctuations of the flow field as well as the mixture preparation in a realistic four-stroke internal combustion engine with variable charge motion system. Based on the analysis of cycle-to-cycle velocity fluctuations of in-cylinder flow, the impact of various fuel spray boundary conditions on injection processes and mixture preparation is pointed out. The joint effect of both cycle-to-cycle velocity fluctuations and variable spray boundary conditions is discussed in terms of mean and standard deviation of relative air–fuel ratio, velocity and mass fraction. Finally a qualitative analysis of the intensity of cyclic fluctuations below the spark plug is provided.

Keywords

Large Eddy Simulation (LES), Cyclic Variations, Direct Injection Spark Ignition (DISI), Internal Combustion Engine, Air–Fuel Mixing, Fuel Spray Injection.

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