Engine Dynamics Library - Release Information

Version 1.2.4 is a maintainance release of the Engine Dynamics Library for Dymola 2016 FD01.

Conversion of user libraries

No conversion is required.

Requirements

Engine Dynamics Library 1.2.4 is based on the Modelon Base Library 2.3 and Modelica Standard Library 3.2.1. It has been tested on

  • Dymola 2016 FD01
  • Dymola 2016

Version 1.2.3 is a minor update of the Engine Dynamics Library.

Improvements

  • Improved Modelica compliance.

Conversion of user libraries

No conversion is required.

Base Library

Engine Dynamics Library 1.2.3 is based on the Modelon Base Library 2.2 and Modelica Standard Library 3.2.1.

Available for: Dymola 2014 FD01

DependenciesModelica Standard Library Version: 3.2

Conversion: None from 1.8.4

  • A new information section is included directly in the library, with guidelines on component testbench and cycle initialization.
  • Handling of refrigerant properties at the receiver outlet is improved for low or zero-flow simulations.
  • In- and outlet pressures, enthalpies and pressures in heat exchanger summary records properly take into account headers, in case those are activated. Previously, only the active heat exchanger part was considered for temperature and enthalpy variables. Enthalpy deviations from previous results are only expected, if heat transfer between headers is possible, temperature may be slighthly different in the two-phase region, due to the additional pressure drop in the headers. This concerns only summary variables, other model variables are unaffected.
  • The variability of correction factors for heat transfer and pressure drop in heat exchangers (CF_ ...) has been increased. They are now declared as input variables, which may change over time. As a feature request by many users, this increases the flexibility for user defined modifications. The default behavior of existing models is not expected to change. Manual steps may be required for the conversion of models for pressure drop and heat transfer correlations, which were copied and modified from previous versions of the library. Please, contact support, if you experience problems.
  • Display units in the four-value display visualizer are corrected to be consistent with the actual value.

Version 1.2.2 is a minor update of the Engine Dynamics Library.

Improvements

  • The simplified heat exchanger components based on efficiency (table based and eps-NTU models) have been improved in that the maximum transferable heat is now correctly computed from the enthalpy difference and flow rates of both sides. Previously this assumed uniform specific heat capacity which in rare cases could result in non-physical solutions.
  • All user calibration factors for heat transfer and pressure drop has been converted from parameters to inputs. Users may still assign them with fixed values in the parameter dialog, but can now also use variable expressions to define calibration factors.
  • Improved flexibility of discretized pipe models. The component can now be configured to expose a flow or control volume behavior at the component boundaries.
  • Improved Modelica compliance.
  • Updated for compatibility with Modelon Base Library 2.1

Conversion of user libraries

Automatic conversion from EDL 1.2.1 is supported using the included conversion script.

Base Library

Engine Dynamics Library 1.2.2 is based on the Modelon Base Library 2.1 and Modelica Standard Library 3.2.1.

09-05-2014

Available for: Dymola 2015

Dependencies: Modelica Standard Library Version: 3.2.1 and Modelon Base Library 2.0

Conversion: 

 

Version 1.2.1 is a minor update of the Engine Dynamics Library. Updates:

  • Removed comparison of enumeration types with Integers. This is not legal Modelica.
  • Updated for compatibility with Modelon base library 2.0

 

Available for: Dymola 2014 FD01

Dependencies: Modelica Standard Library Version: 3.2.1 and Modelon Base Library 1.9

Conversion script from 1.1 provided.

  • Discretized pipe models for air and exhaust are now available in the Engines.Pipes package.
  • Lumped heat exchanger models based on the eps-NTU approach have been added. These are generic models with replaceable effectiveness functions for different flow configurations and replaceable correlations for pressure drop and heat transfer coefficients. The model also accounts for thermal resistance of the wall and can capture first order dynamics of the heat transfer.
  • In addition to the exhaust - liquid heat exchanger configuration, the available heat exchanger models have been extended to air - liquid and air - air variants to allow modeling of different charge air coolers variants.
  • Generic pipe, volume and heat exchanger components inherit the parameter declaration from base classes in the Modelon Base Library to facilitate design of heat exchanger and stack templates and ensure component compatibility and replaceability between different Modelon libraries.
  • Improvements in the medium packages reduce the number of warnings during model translation.
  • Static head can be accounted for by the different pipe models.
  • Table based components now use the Modelon.DataAccess functions that handles more possible data input formats and extrapolation options.
  • Engine Dynamics Library 1.2 has been updated for MSL 3.2.1.

Version 1.1 is a major update of the Engine Dyamics Library.

New features

Several new components have been added to facilitate creation of engine system model with very few states. Such models may be desirable in order to improve simulation speed of desktop simulations and SIL applications, and are suitable to linearize in case the model should be used for model based control system development. The new components created for this purpose are:

  • A set of new volume components that assumes quasi-static temperature and positive flow rate (in design direction). Replacing the regular compressible volume components with these will remove all gas temperatrue state variables in the system, significantly reducing the total number of states. The new components are found in the package EngineDynamics.Engines.Volumes.StaticTemperature.
  • Specialized turbo components (Compressor, Turbine and VGT) that use a custom rotational connector including only the angular velocity and cut torque. By excluding the angular position of the turbo one state variable can be removed. Note that since a special connector is used, these components are not compatible with other rotational mechanical components. The new turbo components are available in the EngineDynamics.Engines.Turbo package and are identified by the class name ending with "_Velocity". Some additional components that are compatible with the new rotational connector can be found in the packages EngineDynamics.Engines.Mechanical and EngineDynamics.Sources.Mechanical.
  • An engine template using the simplified components is available as EngineDynamics.Engines.Templates.TurboChargedEGR_Reduced and an example experiment model of the engine is available as EngineDynamics.Engines.Experiments.Examples.TestCellExample_Reduced. The number of state variables in the two models are 27 and 18 respectively.

In addition to this, these new components have also been added:

  • A simple equation based mean value model for compression ignited engines, as proposed by Wahlström & Eriksson (2010, 2011).
  • A compressor map option based on equations rather than table look-up. The map equations have been selected to handle extrapolation in the low speed region as accurate as possible. This is essential as manufacturer performance maps rarely cover the full speed range that occurs in engines. A function is also included to perform least squares fitting of the model parameters to a compressor map.
  • A simple equation based turbine map option based on Stodola's cone law.

Other improvements

  • The cylinder templates can now accept any of the following inputs from the combustion model: Energy conversion efficiency (Indicated / Fuel MEP), Indicated MEP or shaft torque.
  • The table based heat exchanger model has been updated with a constant parameter for efficiency multiplier. This allows quick constant modifications to the efficiency without requiring updates of the actual table.
  • The parameterization of the inlet manifold has been updated with pre-defined options for the matrix defining how air is mixed into the exhaust gas representation. A manual option is still available.
  • The library package structure has been updated a bit. Engine components are now found in the under the Engines package.
  • Improved the parameter dialog of the gas and liquid pressure sources, only the parameters that affect the fluid properties for the given parameterization option are now enabled.

Fixed bugs

  • In the cylinder template with a simple mass balance (for use with a simplified 2-component exhaust model) EngineDynamics.Engines.Cylinder.Templates.PartialCylinderSimpleMassBalance, when setting the parameter fuel_flow_min = 0 and providing zero inlet fuel flow, the equation for the excess air factor lambda would result in division by zero. This has been fixed by limiting the denominator by Modelica.Constants.eps.

Conversion of user models from 1.0

Some classes have moved in the library structure or changed name since version 1.0 of EDL. The provided conversion script can perform all required conversions of user models.

Base Library

Engine Dynamics 1.1 is based on the Modelon Base Library 1.8