Modeling and Analysis of a High Performance Engine Cranktrain
Michele CALABRETTA – Automobili Lamborghini, S.p.A.Peter NGUYEN – Gamma Technologies, Inc.
•Correlation to Lamborghini Bearing Tool
•Bearing Orbit
•Bearing Load Map
•Failure Criteria
•Correlation to Lamborghini Torsional Vibration Tool
•Lightweight Crankshaft Study
•Development of GT-SUITE 3D-Beam Model
•FEA inputs
•Correlation to rigid bearing results
•Correlation to torsional results
•Fast GT-SUITE analysis of counterweight under-balance
•Correlation to Lamborghini Bearing Tool
•Bearing Orbit
•Bearing Load Map
•Failure Criteria
•Correlation to Lamborghini Torsional Vibration Tool
•Lightweight Crankshaft Study
•Development of GT-SUITE 3D-Beam Model
•FEA inputs
•Correlation to rigid bearing results
•Correlation to torsional results
•Fast GT-SUITE analysis of counterweight under-balance
Torsional Vibration Correlation
Calculated crank nose torsional vibrations (red lines) plotted on the experimental measured signal shows good correlation.
Lightweight Crankshaft Study•Crankshaft Geometry Modified in CAD/FEM
•Reduced Stiffness, Lower Eigenfrequencies
•Torsional vibration most severe in Journal 3 but only over overspeed condition
•Correlation to Lamborghini Bearing Tool
•Bearing Orbit
•Bearing Load Map
•Failure Criteria
•Correlation to Lamborghini Torsional Vibration Tool
•Lightweight Crankshaft Study
•Development of GT-SUITE 3D-Beam Dynamic Model
•FEA inputs
•Correlation to rigid bearing results
•Correlation to torsional results
•Fast GT-SUITE analysis of counterweight under-balance
Construction of Beams• 2, 3, or 4-noded Beam FE primitives are used to model different crankshaft
components such as Journals, Crankwebs and Crankpins.
ElementsNodes
Validation of Dynamic Beam Model
”Energy decaying scheme for non-linear beam models” Bauchau, O.A. and Theron, N.J. Computer Methods in Applied Mechanics and Engineering. Vol. 134, no. 1-2, pp. 37-56. 1996
Correlation of Pure Torsion and Dynamic Bending – High RPM
-Possible combination of bending and torsional modes
•Correlation to Lamborghini Bearing Tool
•Bearing Orbit
•Bearing Load Map
•Failure Criteria
•Correlation to Lamborghini Torsional Vibration Tool
•Lightweight Crankshaft Study
•Development of GT-SUITE 3D-Beam Dynamic Model
•FEA inputs
•Correlation to rigid bearing results
•Correlation to torsional results
•Fast GT-SUITE analysis of counterweight under-balance
Current crankshaft design is overbalanced•From classical engine theory, overbalance allows for lower peak bearing forces
•Axial crank-slider reciprocating forces reduced
•Some tangent centrifugal forces added
•Optimization of counterweight size allows lower crankshaft inertia and mass
•Faster engine response
*Norton, Robert L. "Balancing the Single Cylinder Engine." Design of Machinery: an Introduction to the Synthesis and Analysis of Mechanisms and Machines. 2nd ed. Boston, MA: McGraw Hill, 2001. Print.