Rapid Evaluation of Variable Valve Lift Strategies Using 3-D In-Cylinder Flow Measurements

Variable valve lift strategies were evaluated using a Water Analog Engine Simulation Rig with 3-D Particle Tracking Velocimetry (3-D PTV) to measure the 3-D flow field at the end of the intake stroke. The measurements were carried out with a 4-valve, pent-roof type head. The intake valves were actuated by independently controlled servo systems to allow various valve lift profiles to be implemented in software. For each configuration, a minimum of 100 cycles were acquired and processed. Ensemble averaged 3-D mean and fluctuating flow fields were extracted. In addition, a number of integrated parameters (total and fluctuating kinetic energy; swirl, tumble and cross-tumble ratios) were calculated for each case.