Valvetrain Design Analysis
Valvetrain Dynamics and Kinematics, Cam Design
GT-SUITE features a complete set of tools for valvetrain engineering in a single environment. Using these, engineers can focus on valvetrain design issues such as stability, durability and noise, as well address the inherent tradeoffs between these design issues and engine breathing and performance. The valvetrain analysis toolboxes in GT-SUITE cover the following valvetrain design and analysis functions:
- Valve lift curve synthesis, polynomial cam design
- Valvetrain mechanism kinematics
- Valvetrain quasi-dynamic analysis
- Valvetrain multi-body dynamic analysis (rigid, flexible bodies)
- Valvetrain tribology (contacts, friction joints)
- Hydromechanical elements (HLA, cam phaser, etc.)
- Camshaft torsional vibrations (time and frequency domain)
- Camshaft bending and bearing oil films
Models involving the above may also be (and are often) integrated with models of engine Performance, Cranktrain, Timing Drives (gear, chain or belt) and Hydraulics (e.g. cam phaser, engine brake, hydraulic valve actuation) in order to account for and study interactions, especially for transient applications.
The cam design, valvetrain kinematics and quasi-dynamic analysis functions can also be performed in VTdesign, a tool for rapid interactive execution of these tasks for common valvetrain configurations, in a visual environment and without “building” a model. Once a cam and valvetrain mechanism is kinematically studied and “designed” in VTdesign, a GT-SUITE model of the valvetrain mechanism for subsequent dynamic analysis and integrated simulations is automatically created (with a single click). VTdesign is distributed at no additional cost to all licensees of GT-SUITE.
In GT-SUITE valvetrain systems are dynamically modeled as a collection of rigid and/or flexible interacting bodies. Single valvetrain branches or entire valvetrain systems, including camshafts/bearings and timing drives, can be modeled. All contacts can be analyzed in detail (Hertz,EHD) to predict contact stress, oil film thickness and friction losses. Helical valve springs are analyzed with distributed mass and stiffness to correctly capture spring natural frequencies, model spring surge, coil clash and predict shear and contact stresses. Flexible bodies (e.g, pushrod, rocker or finger) may be modeled in GT-SUITE, or reduced FE models (M, K matrices, selected eigenvectors) may be imported from a commercial FEA tool. Models provide many valvetrain-specific predictions, such as metrics for (valve) seating velocity, cam-follower separation, spring margin, and valve-piston interference.
The valvetrain analysis functionality is based primarily on two underlying general-purpose mechanical analysis libraries of GT-SUITE:
- Multi-body Dynamics (MBD) : 1D/2D/3D/Flexible bodies
- General Planar Kinematics
These libraries are also available to GT-SUITE users at no additional cost. Components from the MBD library may be used in conjunction with higher-level valvetrain-specific toolbox components, or stand-alone in order to model general mechanical systems. The General Planar Kinematics library extends the reach of GT-SUITE valvetrain kinematics to non-conventional valvetrain, mechanical variable-valve-actuation (VVA) and general mechanisms.
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| Gamma Technologies, Inc. 601 Oakmont Lane, Suite 220 Westmont, IL 60559 USA |
Tel. Fax. (630) 325-5849 Email: CAE@gtisoft.com Web: www.gtisoft.com |
APPLICATIONS
Engine Performance
Test Pressure Analysis
Exhaust Aftertreatment
Acoustics
SiL, HiL, real-time
Vehicle, driveline
Hybrid Vehicles
Cooling/VTM
Underhood Modules
AC and Rankine
Lubrication and bearings
Fuel Injection
Hydraulics, pneumatics
Valvetrain, camshaft
Cranktrain, crankshaft
Chain, gear, belt drive