Internal Combustion Engine Laboratory, Department of Mechanical Engineering Indian Institute of Technology Madras, Chennai - 600 036, India
This paper deals with the investigations of the in-cylinder flow pattern around the intake valve of a single-cylinder internal combustion engine using Particle Image Velocimetry (PIV) at different intake air flow rates. The intake air flow rates are corresponding to the three engine speeds of 1000, 2000 and 3000 rev/min., at all the static intake valve opening conditions. In this study, in-cylinder flow structure is characterized by the tumble ratio and maximum turbulent kinetic energy of the flow fields. In addition, at two specified lines of the combustion chamber, the radial and axial velocity profiles have been plotted. From the results, it is found that the overall airflow direction at the exit of the intake valve does not change significantly with the air flow rate and intake valve opening conditions. The tumble ratio increases with increase in intake valve opening and not much affected by the change in the air flow rates. It is also found that, the variations of the velocity profiles at the two specified lines are smooth at full intake valve opening irrespective of the air flow rate. Also, their magnitudes increase with increase in the intake valve openings at all the air flow rates. The in-cylinder flow analysis carried out in this study may be useful for optimizing the intake valve opening of an internal combustion engine with respect to it’s speed.