Model Verification of CAE with NVH-Test Acting on Downsized Car Engines
Published June 5, 2019 by SAE International in United States
Downloadable datasets for this paper availableAnnotation of this paper is available
Today’s trend of combustion engine development for cars is characterized with; high torque, low engine speed, low weight, high degree of cyclic irregularity, low excitation frequency due to fewer cylinders active e.g. 4-cylinder or less.
This implies in respect of vibrations that it is crucial to control powertrain rigid body modes and place these were they cannot be reached and induced by the low exciting harmonic frequencies for low engine speeds or idling. It is also important to control the overall flexible vibration modes.
A mathematical CAE model is created in simulation software AVL-EXCITE in order to handle the vibration phenomenon as a first step. But it is absolutely necessary to “verify” these models with real measurements in respect of NVH and if needed upgrade the CAE model if there are detected deviations. The NVH-test is done with testing tool DEWESoft.
The purpose of below paper is to do model verification on a concrete example in respect of powertrain vibrations. Volvo Cars in-line 4-cylinder VEA diesel engine in rig installation is the object for the paper of model verification.
Method of this work has been to do simultaneously NVH measurements of vibrations, torque and cylinder pressure traces during different engine load conditions. Also bump test with a modal hammer has been done in order to find rigid body mode frequencies.
The measured cylinder pressure is applied as input to the simulation model in order to have consistent input load between test and simulation. This is important when comparing the output vibrations.
Verify and compare crank angle based time domain vibrations signals from CAE model with NVH-testing on a real engine. This is the results of the work.
CitationRönnqvist, U. and Ribarits, J., "Model Verification of CAE with NVH-Test Acting on Downsized Car Engines," SAE Technical Paper 2019-01-1550, 2019, https://doi.org/10.4271/2019-01-1550.
Data Sets - Support Documents
|[Unnamed Dataset 1]|
- Ford, D.M. , “An Analysis and Application of a Decoupled Engine Mount System for Idle Isolation,” SAE Technical Paper 850976 , 1985, doi:10.4271/850976.
- Maas, H. and Klier, H. , Kräfte, Momente und deren Ausgleich in der Verbrennungs - kraftmaschine, Neue Folge Band 2 (Wien, New York: Springer-Verlag, 1981). ISBN:3-211-81677-1.
- Martyr, A.J. and Plint, M.A. , Engine Testing, The Design, Modification and Use of Powertrain Test Facilities, Fourth Edition (Butterworth-Heinemann, 2012). ISBN:9780080969497.
- Racca, R. , “The Use of Isolators for Attenuating Dynamic Disturbances Generated by Small Internal Combustion Engines,” Paper, Barry Controls, A Unit of Applied Power Inc.