zissimos p. mourelatos, associate prof. paras shah, prashant patel; graduate students
DESCRIPTION
z. Z. CM 1. E. Piston FEA model (incl. Thermal & elastic effects). α -θ y. CH. CM. α. ZG. Contact Force time history. Block Impulse response. Block response time history. x. P 1. conv. P. Engine Block Vibratory Response. θ y. XG. x. =. fft. ifft. fft. PO +δ P. A. - PowerPoint PPT PresentationTRANSCRIPT
Zissimos P. Mourelatos, Associate Prof.Paras Shah, Prashant Patel; Graduate Students
Simulation of Piston Secondary Dynamics, Piston-Bore Contact and Piston Slap
•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.
• 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
•Objectives
Engine “Piston – Bore” InteractionNoise Generation Mechanism
Engine Piston Noise Sources
Engine “Piston – Bore” Interaction Effects
•Analysis• Piston skirt elastic deformation
• Asperity contact analysis
• Engine block vibration
• Thermal deformation
• Piston - skirt ElastroHydroDynamic (EHD) lubrication
Piston Temperature Distribution
Datum
A
B
C
D
E
Sk
irt
Pro
file
Piston Dynamic Contact Analysis
Optimization of Skirt Profile for Minimum Contact Pressure
Piston Dynamic Forces
PP1
CM
CM1
α
PO+δP
CH
x
z
X
Z
θyXG
ZG
α-θy
θ
Schematic: Crank Slider Mechanism
Piston FEA model (incl. Thermal & elastic effects)
Piston skirt - liner contact modeling
Piston secondary dynamics
Engine Block Dynamics using Frequency Response Functions
Engine Block Vibratory Response
•Engine Vibration Prediction
Contact ForceSpectrum
Block FRFx Block Response
Spectrum
=
Contact Forcetime history
fft ifftfft
BlockImpulse response
Block response time historyconv
x =
•Uncertainty in Piston Design• Sensitivity analysis of piston design parameters
on piston slap excitation under uncertainty