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

Bearing Orbit – Correlation

Peak Power RPMLamborghini Tool

GT-SUITE

Lamborghini Tool

GT-SUITE

Bearing Load – Correlation

Peak Torque RPM

Bearing Failure Criteria – Correlation

•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

Lightweight Crankshaft Study•Significant excitation of the 2nd Eigenfrequency.

•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

Bending Stiffness Analysis

Animation of the deformed crankshaft

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

Typical Bearing Result –Rigid vs. Dynamic

Bearing Failure Criteria –Rigid vs. Dynamic

Correlation of Pure Torsion and Dynamic Bending – Low RPM

Correlation of Pure Torsion and Dynamic Bending – High RPM

-Possible combination of bending and torsional modes

Additional Vibration Modes present in Dynamic Bending

•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.

Effect of Counterweight ReductionMinimum Oil Film Thickness

Peak Oil Film Pressure

•Combined stress analysis from Dynamic model

•Development of reduced finite element model in GT-SUITE v7.1

Future Collaboration Work

Thank you to primary contact at Lamborghini, Dr. Michele CALABRETTA