Engine

Create Cylinder and Valves (after import of a CAD model)

Opens a dialog that allows you to specify the engine configuration and engine symmetry. See Engine Parts Creation Dialog.

Using the settings that you specify in the dialog and the filters described in Four-Stroke Engine: CAD Bodies and Faces and Two-Stroke Engine: CAD Bodies and Faces, Simcenter STAR-CCM+ In-cylinder assigns the geometry to the respective Engine Parts and the geometry surfaces to the respective Engine Part Surfaces.

Create Sector Model (after import of a 2D Curve)

Opens the Create Sector Model dialog, which allows you to specify the Number of Sectors for the cylinder sector model.

Using the specified number of sectors, Simcenter STAR-CCM+ In-cylinder creates the Cylinder Sector Engine Part with a wedge angle of $\alpha =\frac{360\mathrm{deg}}{NumberofSectors}$.

The minimum number of sectors is 3.

Replace Cylinder and Valves Geometry (not for cylinder sector models)

Allows you to import a new CAD geometry, which is automatically assigned to the existing Cylinder and Valves Engine Parts without affecting the simulation setup. For more information, see Replacing the Engine Geometry and Re-running the Simulation.

注	If you modified the CAD model of the existing Cylinder and Valves Engine Parts in 3D-CAD (see Edit 3D-CAD Model), swapping the geometry is not supported.

Create Injector (only if the Fuel engine model is selected)

Opens a dialog that allows you to specify the geometry and physics of a fuel spray injector and its nozzles. See Injector Dialog.

Create Ignitor

Opens a dialog that allows you to specify the location and physics of a spark ignitor. See Ignitor Dialog.

Hide

Hides the selected Engine Part from the Graphics window. This action is useful for gaining a clear view of other objects. You can restore hidden objects again by using the Show action.

Show

Restores a hidden Engine Part.

Edit

For Cylinder / Cylinder Sector, opens the Cylinder Dialog, which allows you to specify the initial conditions and the piston motion of the cylinder.

For Exhaust Valve [n] / Intake Valve [n], opens the Valve Dialog, which allows you to specify the motion of the valves.

For Injector, opens the Injector Dialog, which allows you to specify the geometry, placement, and physics of the injector and its nozzles.

For Ignitor, opens the Ignitor Dialog, which allows you to specify the location and the physics of the ignitor.

For Plenum [n], opens the Plenum Dialog, which allows you to specify the initial conditions of the plenum.

Edit Interactions

Allows you to define interactions with other Engine Parts and geometries, see Interactions.

Position

Launches the Positioning Tool that allows you to interactively place the Engine Part in reference to other objects.

Hide

Hides the selected Engine Part Surface from the Graphics window. This action is useful for gaining a clear view of other objects. You can restore hidden objects again by using the Show action.

Show

Restores a hidden Engine Part Surface.

Edit

Opens a dialog that allows you to specify the physical conditions on the Engine Part Surface. See Engine Part Surfaces.

You can apply this action to several Engine Part Surfaces if they are of the same type and if they belong to the same type of Engine Part. For example, you can multi-edit the walls of several valves. Hold down the <Ctrl> key when selecting the Engine Part Surfaces.

Dependencies

Displays dependency relationships of the surface with other objects. See Object Dependencies.

Edit

Opens a dialog that allows you to specify the configuration of an individual nozzle.

Symmetry Plane

Specifies the symmetry of the imported geometry.

• + side: Keeps the + side of the geometry.
• - side: Keeps the - side of the geometry.

Simcenter STAR-CCM+ In-cylinder differentiates the + side from the - side as follows:

1. Finds the centroidal positions of all intake valves.
2. From the centroidal positions of the intake valves, obtains the average coordinates $x_{avg}$ and $y_{avg}$.
3. Calculates a rotation angle IntakeAngleOffset as:

   $IntakeAngleOffset=\arctan 2(y_{avg},x_{avg})$

   If $IntakeAngleOffset<0$, then $IntakeAngleOffset=IntakeAngleOffset+2\pi$

   The following image shows the centroid average of the intake valves and the IntakeAngleOffset:

   
   
   
4. Rotates a cylindrical coordinate system that has the r-axis pointing in the x+ axis direction of the global Cartesian coordinate system and the theta-axis pointing in the y+ axis direction of the global Cartesian coordinate system by IntakeAngleOffset in the counter-clockwise direction.

   The following images show the cylindrical coordinate system before and after rotation:

   
   
   
   
   
   
5. The symmetry plane +side corresponds to the half model on the positive theta-axis side. The symmetry plane -side corresponds to the half model on the opposite side of the +side:
   
   
   

(for a RANS simulation)

The corresponding value nodes become available in the Cylinder and Intake / Exhaust Port [n] group boxes.

For more information, see K-Epsilon Initial Conditions Reference.

Absolute Total Pressure (for Cylinder and Intake Port [n]) / Absolute Static Pressure (for Exhaust Port [n])

Specifies the respective initial pressure as a constant value or in the form of a Table.

The table must define the pressure as a function of crank angle.

Simcenter STAR-CCM+ In-cylinder evaluates the respective value at the specified Start Angle using linear interpolation between the data points:

• File: Sets the file that contains the respective pressure data.

  Import allows you to import a table of one of the following file formats: *.csv, *.txt, or *.dat.

• Crank Angle Column: Sets the header of the column that contains the crank angle values.
• Absolute Total Pressure Column / Absolute Static Pressure Column: Sets the header of the column that contains the pressure values.
• Crank Angle Units: Sets the units of the imported crank angle values—deg or radian.
• Pressure Units: Sets the units of the imported pressure—Pa, bar, or psi.

If no table headers are available, Simcenter STAR-CCM+ In-cylinder numbers the columns starting from zero, such as column0.

Temperature

Specifies the temperature as a constant value or in the form of a Table.

The table must define the temperature as a function of crank angle.

Simcenter STAR-CCM+ In-cylinder evaluates the respective value at the specified Start Angle using linear interpolation between the data points:

• File: Sets the file that contains the temperature data.

  Import allows you to import a table of one of the following file formats: *.csv, *.txt, or *.dat.

• Crank Angle Column: Sets the header of the column that contains the crank angle values.
• Temperature Column: Sets the header of the column that contains the temperature values.
• Crank Angle Units: Sets the units of the imported crank angle values—deg or radian.
• Temperature Units: Sets the units of the imported temperature values—C, F, K, or R.

If no table headers are available, Simcenter STAR-CCM+ In-cylinder numbers the columns starting from zero, such as column0.

Fuel/Oxidizer Mixing State Specification (only if the ECFM-3Z engine model is selected)

Specifies whether the fuel and oxidizer are initially Unmixed or Premixed at the subgrid level.

Omega (only for cylinder sector models)

Specifies the initial velocity in terms of a rotation rate (in units of rpm) about the z-axis of the Cylinder Cylindrical Coordinate System.

Air Mass Weighting / Exhaust Mass Weighting / Fuel Mass Weighting

When Automatic Composition Initialization is On, displays the calculated initial mass weighting of air, exhaust, and fuel vapor. For more information, see In-cylinder Formulation—Gas Initialization and Boundary Conditions

When Automatic Composition Initialization is Off, allows you to specify the initial mass weighting.

Simcenter STAR-CCM+ In-cylinder calculates a given material property, such as density, of the gas mixture as:

$${\varphi }_{\mathrm{mix}}={Y_{air}\varphi }_{air}+{Y_{exhaust}\varphi }_{exhaust}+{Y_{fuel}\varphi }_{fuel}$$

(581)

with:

$$Y_{air}=\frac{W_{air}}{W_{air}+W_{exhaust}+W_{fuel}}$$

(582)

$$Y_{exhaust}=\frac{W_{exhaust}}{W_{air}+W_{exhaust}+W_{fuel}}$$

(583)

$$Y_{fuel}=\frac{W_{fuel}}{W_{air}+W_{exhaust}+W_{fuel}}$$

(584)

where:

• $W_{air}$, $W_{exhaust}$, and $W_{fuel}$ are the specified Air Mass Weighting, Exhaust Mass Weighting, and Fuel Mass Weighting, respectively.
• ${\varphi }_{air}$, ${\varphi }_{exhaust}$, and ${\varphi }_{fuel}$ are the material property values of air, exhaust and fuel vapor, respectively, as defined in Materials.

Bore

Displays the diameter of the engine cylinder, see $B$ in Eqn. (585) and Eqn. (586).

Simcenter STAR-CCM+ In-cylinder calculates this value from the imported geometry.

Stroke

Specifies the distance that the piston travels from BDC to TDC, see $S$ in Eqn. (569), Eqn. (585), and Eqn. (586).

Crank Radius

Displays the distance between the crank center and the crank pin.

If the specified Pin Offset equals zero, the crank radius is calculated as $\frac{S}{2}$, where $S$ is the specified Stroke.

If the specified Pin Offset is not zero, Simcenter STAR-CCM+ In-cylinder maintains the specified Connecting Rod Length and Stroke and uses these parameters to calculate a corresponding crank radius.

Connecting Rod Length

Specifies the length of the link that connects the piston to the crank shaft, see $CRL$ in Eqn. (569).

Pin Offset

Specifies the pin offset, see $PO$ in Eqn. (569).

Zero CA Convention

For engines with a non-zero pin offset, specifies the convention for defining 0 degCA.

For engines with a zero pin offset, 0 degCA describes the position at which the crankshaft is vertical, which coincides with the piston being at Top Dead Center (TDC). However, for engines with a non-zero pin offset, the piston is not at TDC when the crankshaft is vertical.

The following options are available:

• Crank Pin TDC: Defines 0 degCA as the position when the crank pin is at TDC.
• Piston TDC: Defines 0 degCA as the position when the piston is at TDC.

Displacement

Displays the volume that the cylinder displaces when the piston moves from TDC to BDC.

It is calculated as:

$$D=\frac{\pi }{4}{B}^{2}S$$

(585)

where:

• $B$ is the specified Bore.
• $S$ is the specified Stroke.

Compression Ratio

When On, specifies the compression ratio of your engine. Simcenter STAR-CCM+ In-cylinder uses the specified value to calculate the Piston Position Offset as given by Eqn. (570).

When Off, displays the ratio of the cylinder volume at BTD to the cylinder volume at TDC.

It is calculated as:

$$CR=\frac{\frac{\pi }{4}{B}^{2}S+V_{TDC}}{V_{TDC}}$$

(586)

where:

• $B$ is the specified Bore.
• $S$ is the specified Stroke.
• $V_{TDC}$ is the cylinder volume at TDC with the valves closed.

Piston Position Offset

When On, specifies the offset of the imported piston geometry from TDC, see $PPO$ in Eqn. (569).

When Off, displays the offset of the piston as given by Eqn. (570).

Import allows you to import a table of one of the following file formats: *.csv, *.txt, or *.dat.

Crank Angle Units

Displays the units for the imported crank angle values. Currently, only deg is supported.

Lift Units

Displays the units for the imported valve lift values. Currently, only mm is supported.

When the valve lash is zero, the valve lift profile shows smooth opening and closing ramps. Increasing the valve lash moves down the valve lift profile. Typically, the valve lash ranges between 0.1 mm and 0.25 mm.

Example: Setting lash to 0.25 mm.

Example: Setting the profile anchor to 107.0 deg and the cycle anchor to 150.0 deg.

Example: Setting lift multiplier to 0.5.

Example: Setting duration multiplier to 1.2.

Depending on the specified value and the actual valve lift, Simcenter STAR-CCM+ In-cylinder treats the valve curtain interface as follows:

The following options are available:

Example:

(not for cylinder sector models)

For a multi-nozzle injector, the angular distance between the nozzles is given by $\alpha =\frac{360\mathrm{deg}}{n}$.

(not for cylinder sector models)

The direction of the injector axis gives the direction of the rotation according to the left hand rule.

For a half engine model with a multi-nozzle injector, if you specify an even number of nozzles, Simcenter STAR-CCM+ In-cylinder automatically applies an rotation offset angle that depends on your engine symmetry model as tabulated below:

Example:

For a multi-nozzle injector, you specify the origin and the target for one of the nozzles—the reference nozzle. Simcenter STAR-CCM+ In-cylinder automatically duplicates the reference nozzle for the specified Number of Nozzles and sweeps the duplicates around the injector axis.

For a mass flow rate profile that is a function of crank angle, the [injector] : Injection Crank Angle Anchor sets an angular position in the profile, in deg. For a mass flow rate profile that is a function of time, the [injector] : Injection Time Anchor sets a point in time in the profile, in s or in the cyclic time unit degCA.

The [injector] : Injection Crank Angle Target sets the angular position in the engine cycle to which you want to shift the respective injection anchor.

Example: The plot below displays a mass flow rate profile that is a function of crank angle, where the injection starts at 428 deg CA. To shift the start of injection to 450 deg CA, you set the [injector] : Injection Crank Angle Anchor to 428.0 deg and the [injector] : Injection Crank Angle Target to 450.0 deg.

For nozzles of solid/hollow cone injectors, the injection in $\varphi$ direction (in a spherical coordinate system with the injection point as the origin) is weighted so that the sample density is biased along the injection direction.

where:

The Cone Angle Sampling Polynomial Exponent specifies the exponent of the polynomial function $f\left(\gamma \right)$. A value of 1 results in a uniform distribution. An integer value larger than 1 results in a higher sample density at the centerline of the spray.

The following options are available:

The following options are available:

• Constant: Sets the temperature to the specified value.
• Table: Specifies the temperature in the form of a table that defines the temperature as a function of time or crank angle.

  For the table properties, see Mass Flow Rate replacing Mass Flow Rate Column and Mass Flow Rate Units with Fuel Temperature Column and Fuel Temperature Units (C, F, K, or R), respectively.

The following options are available:

• Constant: Sets the droplet diameter to the specified value.
• CDF Table / PDF Table: Sets a table that specifies the distribution of the droplet diameter using a cumulative distribution function (CDF) / probability density function (PDF).
  • File: Sets the file that contains the CDF / PDF data.

    Import allows you to import a table of one of the following file formats: *.csv, *.txt, or *.dat.

  • Data: Sets the header of the column that contains the droplet diameter in m. If no table headers are available, Simcenter STAR-CCM+ In-cylinder numbers the columns starting from zero, such as column0.
• Rosin-Rammler: Sets the distribution of the droplet diameter using a Rosin-Rammler size distribution.
  • Minimum Diameter: Sets the minimum droplet size that the distribution generates.
  • Maximum Diameter: Sets the maximum droplet size that the distribution generates.
  • Sauter Mean Diameter: Specifies $\mathrm{SMD}$ in Eqn. (577).
  • Exponent: Specifies $q$ in Eqn. (577).

(only if the the FI Spark-Ignition engine model is selected)

(only if the FI Spark-Ignition engine model is selected)