zissimos p. mourelatos, (associate professor) paras shah, prashant patel; (graduate students)...
TRANSCRIPT
Zissimos P. Mourelatos, (Associate Professor)
Paras Shah, Prashant Patel; (Graduate Students)
Simulation of Piston Secondary Dynamics, Piston
– Bore Contact and Piston Slap
Motivation
Piston slap is an NVH phenomenon that 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, specially at cold start.
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
Theoretical Aspects
Kinematics: Crank-slider mechanism Piston secondary motion Piston dynamics model Engine piston-bore interaction effects Skirt - liner dynamic interaction forces
Datum
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Ski
rt P
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E
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DDatum
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Ski
rt P
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Piston Dynamic Contact Analysis
Optimization of Skirt Profile for
Minimum Contact Pressure
Analysis
Piston skirt elastic deformation Asperity contact analysis Engine block vibration Thermal deformation Piston-skirt ElastroHydroDynamic (EHD)
lubrication
Piston Temperature Distribution Skirt Thermal Deformation (Thrust Side)
Piston Temperature Distribution
PP1
CM
CM1
α
PO+δP
CH
x
z
X
Z
θyXG
ZG
α-θy
θ
PP1
CM
CM1
α
PO+δP
CH
x
z
X
Z
θyXG
ZG
α-θy
θ
Schematic: Crank Slider Mechanism
Skirt Contact Forces on Thrust side for various Clearances