Zissimos P. Mourelatos, Associate Prof. Paras Shah, Prashant Patel; Graduate Students

1. z Z CM1 E Piston FEA model (incl. Thermal & elastic effects) α-θy CH CM α ZG Contact Force time history Block Impulse response Block response time history x P1 conv P Engine Block Vibratory Response θy XG x = fft ifft fft PO+δP A Piston secondary dynamics Block FRF Block Response Spectrum Contact Force Spectrum = x Piston skirt - liner contact modeling Skirt Profile Engine Block Dynamics using Frequency Response Functions C Datum D θ B X Optimization of Skirt Profile for Minimum Contact Pressure Piston Dynamic Contact Analysis Engine “Piston – Bore” Interaction Noise Generation Mechanism Engine Piston Noise Sources Piston Temperature Distribution Engine “Piston – Bore” Interaction Effects Piston Dynamic Forces • Engine Vibration Prediction • Uncertainty in Piston Design • Sensitivity analysis of piston design parameters on piston slap excitation under uncertainty Schematic: Crank Slider Mechanism Simulation of Piston Secondary Dynamics, Piston-Bore Contactand Piston Slap Zissimos P. Mourelatos, Associate Prof.Paras Shah, Prashant Patel; Graduate Students • Motivation • Piston slap is an NVH phenomenon which is a strong customer dissatisfier (unusual engine noise). • Noise is an important contributor to Quality, Reliability, and Durability (QRD). • Piston slap is a significant contributor to the total Engine Noise, especially at cold start. • Analysis • Piston skirt elastic deformation • Asperity contact analysis • Engine block vibration • Thermal deformation • Piston - skirt ElastroHydroDynamic (EHD) lubrication • Objectives • Simulate piston secondary motion • Determine side thrust forces due to piston - cylinder liner contact • Reduce piston slap excitation • Predict engine block vibration due to side thrust forces