Engines Library
The Engines library is capable of modelling both Spark Ignition and Compression Ignition engines and is split into two variants with different levels of fidelity. Both versions of the Engines library have been designed to work with common engine architecture templates. This enables quick model set-up and ensures a consistent layout for a variety of engine model architectures. The engine model library has been developed in Modelica and is available for Dymola.
The Mean Value version of the Engines library predicts the cycle averaged intake and exhaust flows, emissions and torque. The Crank Angle Resolved version predicts the complete cyclic intake and exhaust flows and torque.
Mean Value Version
The Mean Value version predicts the cycle averaged air flow and torque produced by the engine. The cylinder mass flow rates are calculated through an equation based approach allowing the engine capacity to be scaled within reasonable limits. This enables downsizing studies to be carried out using the library.
The combustion and emissions modelling is map based using manifold pressure and engine speed as the primary inputs to the maps with further corrections for spark timing and afr.
This version of the Engine library is particularly suited to driveability analysis where the effect of throttle transients on the driveline behaviour are investigated. In addition, this version of the library is also suited to catalyst light-off investigations.
Crank Angle Resolved Version
The Crank Angle Resolved version predicts the cyclic variations for air flow and torque. This is an extension to the Mean Value version of the engine model library.
The combustion heat release is modelled through a Wiebe model with table based coefficients. The table defines the Wiebe model coefficients at different engine speeds. Both Compression and Spark ignition heat release models are available. Port fuel and direct injection are also supported.
The flow though the engine block is dictated by the valve geometry and opening characteristics and the piston-cylinder assembly model. Valve and spark timing effects on the fluid dynamics and combustion model mean that the engine performance can be investigated using this version of the library.
This version of the Engine library is particularly suited to driveline, nvh analysis, mount excitations, cranking and detailed friction modelling.
Further Information
Download the complete brochure for more details
Dymola
