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Release Notes 2020 R2

Virtual Driveline Development - Transmission and E-Drive

At AVL we continually update and improve our products and services, in order to address the evolving needs of our customers and the changing automotive landscape. Right across our business we add new features and enhancements and make improvements to existing products.

These improvements happen in all solution areas, including Transmission E-Drive. Here is an outline of some of the revisions that have been made in this latest release.
 

EXCITE™ e-Axle


A new EXCITE™ module for:

  • Easy and efficient modeling of gearbox-configurations especially designs that are used in recent e-Axle-drives
  • New 3D-graphical environment with proven EXCITE Power Unit Kernel
  • Gear-system modeler which comes with EXCITE e-Axle is tailored to configurations comprising cylindrical gear stages as well as planetary gearsets

 

Figure 1: e-Axle with PGS and Cylindrical Gear Stages in 3D-Viewer

 

With the first release of the EXCITE e-Axle module its functionality is specialized for stationary e-Axle applications. However, the generic modeling approach is suitable for the creation of models of other gearbox configurations comprising PGS and cylindrical gears.

 

Figure 2: Model of a manual transmission


By having different modeling levels like BASIC and EXPERT, you can simulate gearbox-systems easier for beginners, all while leaving the experts free to create sophisticated high-end models.

Novel functionality and features:

  • Full hierarchical 3D modelling supported by advanced component selection making the need of 2D-block modelling unnecessary
  • Specialized focus-views revealing insights to component's dimensions and relevant layout data

 

Figure 3: Focus-views for gear shaft, gear-pair, and rolling element gearing
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  • Predefined assembly for planetary gearset modeling
Figure 4: Planetary gearset assembly

 

  • Automatic solution of geometric/kinematic constraints (“gear phasing”) including kinematic system animation
  • Map-based electric machine joint (EMCM) for efficient application of distributed e-motor stator forces supporting force-import from AVL's Electric Motor tool as well as other third party electro-magnetic simulation tools by generic import functionality
  • Advanced suggestions based on component boundary dimensions to counteract the frequent problem of unknown geometry inputs (e.g. at rolling element bearings, or splines)
  • Extended visualization of applied system loads and predefined motion
     
Figure 5: Visualization of applied loads

 

  • COMPOSE™ App for gearbox reports, including gear contact patterns and rolling element bearing force distribution plots
Figure 6: Report generation by COMPOSE App

 

  • IMPRESS M™ 3D Animation of the whole gearbox system comprising body results as well as detailed contact results in gear pairs, rolling element bearings and spline gears
Figure 7: Animation of body and joint results using IMPRESS M

 


EMCM – EM Coupling (map-based torque) Joint

EMCM joint for electric machine, available in EXCITE eAxle, covers the electro-mechanical coupling by applying tooth forces to the stator and a counter torque to the rotor body. This allows dynamic and acoustic analysis of the e-Axle. Effects like torque and force ripple are captured. You can also analyze configurations with static eccentricity.

The impact of speed fluctuations on the electrical side is disregarded. Therefore, EMCM only allows stationary as well as quasi-stationary analysis, when speed or load changes are small compared to the reaction time of the machine’s control system.

Data based on single operation points or a whole operation map can be imported from the AVL E-Motor Tool (for Permanent Magnet Synchronous Machines) as well as arbitrary third party electro-magnetic tools by a generic ‘Import data’ dialog. Force data must be given in polar coordinates with respect to each tooth.

The joint is capable to complete stator tooth force data by angular shift and replication. It is thus possible to restrict electro-magnetic simulations to for example, one pole pair or restrict file output to the number of teeth per pole and phase. The joint interpolates within the given operation points. Hence, with adequately fine resolution of the map it is possible to simulate slow transient operations as full load run-up.
 

Figure 8: Application for distributed stator forces



Component Modeler

Along with the new module EXCITE e-Axle, also a new modeling client has been introduced for FEM-based flexible body representations - named Component Modeler (CM). It helps the users to

  • Easily create retained nodes in a FEM-model according to the required connection nodes demanded from EXCITE e-Axle's Link Locations (LL)
  • Define new node and element sets offers basic functionality to create Multi Point Constraints (MPC) of different types in order to establish the relations between connection/retained nodes and depending FEM-nodes
Figure 9: Component modeler with highlighted retained nodes and multi-point constraints (MPCs)

 

  • Condensation of the FEM-Model can be directly invoked from of the component modeler and all the required definitions like retained degrees-of-freedom, MPC's and node/element sets are automatically passed to the Condensation App. This promotes a very simple transition from rigid/structured modeling of bodies towards FEM-based flexible body representations

With the current release the component modeler comes with basic functionality in order to support the new module EXCITE e-Axle. However, in future releases its functionality is planned to be extended for a more complex node/element search, generation of membrane meshes for EHD contacts as well as native CAD import and meshing.

Electric Motor Tool

EM Model Assistant - Map-based (tooth forces)

The EM Model Assistant supports the electric machine joint with the map-based (tooth forces) model. The user has the possibility to specify a table of operation points or an operation map, for example, full load over speed or constant torque over speed. The E-Motor tool automatically conducts magnetic simulations to obtain stator tooth forces. Two options are offered to parameterize the electrical currents for each point, direct input of current tables or automated evaluation of the current tables for the specified operation points. Mind that in the latter case delivered currents may lead to deviation in the torque as a fundamental wave model is used for assessing the currents based on the maximum torque per ampere (MTPA) principle. The model supports the data format of EXCITE e-Axle for pure electric powertrain applications as well as EXCITE Power Unit with the Load-definition for hybrid applications. The geometry of the machine can be based on CAD, geometry templates or from previously conducted concept design in E-Motor tool.
 

Figure 10: Electric Motor Tool - EM Model Assistant - map based (tooth force)


 

EXCITE™ Power Unit


New features
Advanced Cylindrical Gear: Inner Gear Deformation Options

  • ​​​​​​Meshing stiffness allows you to consider the meshing stiffness contributions due to flank contact (Hertz-Peterson) as well as tooth bending (Weber/Banaschek)
  • Regarding the deformation of the ring (annulus), Chen/shao has introduced a new method With this approach the ring gear is divided into curved beams connected at support points assuming certain mounting boundary conditions
Figure 11: Options for gear deformation


Using the dialog "Support Internal Gearing" the support points can be defined in cartesian and polar coordinate systems, respectively. The boundary conditions are either fixed or pinned.

Figure 12: Dialog for defining support point positions and boundary conditions
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Figure 13: Boundary conditions for the supports


With the new options for ring gears it is possible to consider all relevant deformation contributions coming from the flank contact, the tooth bending and the ring bending in order to achieve more realistic results for the predicted mesh stiffness.
 

Figure 14: Meshing stiffness depending on the position of the planet relative to the support points of the ring


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Enhancements

Roller Bearing: Contact Length Depending on Penetration Depth

  • ​​​​​​​Effective contact length can be defined depending on the penetration depth. The change of the length is specified by a table, which scales the length according to the contact penetration. This can be done either with a scaling factor or with absolute values
Figure 15: Predefined table of contact length vs. penetration Length


By means of this approach the effect of the reduced bearing stiffness due to rolling element crowning/barreling can be considered more realistically. Below outlines how the value of the effective contact length varied over the penetration depth (positive depth indicates contact) and consequently influences the computation of the contact stiffness between rings and rolling elements.
 

Figure 16: Contact length changing with penetration depth for different rolling elements


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Load Data Extension for E-Motor NVH and Multipurpose Use

You can now import possibilities in the ‘Load Data’ dialog and replicate load items. We provide two loops for data import to generate multiple load items from a specified base item. With this, it is possible to import data, for example, for multiple operation points and a set of nodes. You can also replicate the definition of body loads analogously. This automates the workflow to import stator tooth forces for NVH-analysis of electric motors for different operation points.

The AVL E-Motor tool completes this feature with automated electromagnetic analysis for stator tooth forces at arbitrary operation points from CAD or geometry templates for permanent-magnet synchronous machines. It thus provides the necessary electro-magnetic input for NVH-analysis of electrified powertrains with the EXCITE™ power unit. You can also import force/torque data from third party tools in an appropriate file structure and format.
 

Figure 17: Duplicate and replicate load Items in load data


You can import force/torque data from third party tools with an appropriate file structure and format.