Constructing the customized supercomponent

Step 1: Load the generic supercomponent in Component Customization

Hide all variables and parameters.

Step 2: The original external variable names have very inappropriate names

Change them to those indicated.

Figure 49: Alter the external variable names

For the time being, only external variables of the supercomponent are visible. We must decide on what else is to be visible. There are many pairs of submodels in this supercomponent. In order to demonstrate the use of global parameters, we will assign the same values to many parameters from the intake side and from the exhaust side. This symmetry is of course not necessary and may not be desirable from a design point of view, but this is not the point of the exercise.

It would be convenient to have the following parameters to set in Simcenter Amesim:

• valve spring preload

• valve spring stiffness

• valve clearance

• valve mass

• maximum possible valve lift

Results

We set these parameters once and they are applied to both the intake and the exhaust side. To do this we introduce customized supercomponent global parameters in Component Customization. These are like global parameters in Simcenter Amesim but their scope is solely the customized supercomponent.

The table below shows the global parameters we will use and an indication of where they will be used. They are all Real parameters but we could also use Integer and Text parameters.

Global type and name	Title [units]	Min./Default/Max.	Submodel, parameter/variable and title
Real VPRELOAD	valve spring preload [N]	200/300/800	SPR000A, real parameter, free length of spring
Real VSTIFF	valve spring stiffness [N/m]	1.0e4/1.0e6/1.0e6	SPR000A, variable, spring rate
Real VCLEAR	valve clearance [mm]	0.05/0.1/0.2	LSTP00A, variable, gap or clearance with both displacements zero
Real VMASS	valve mass [kg]	0.005/0.01/0.05	MAS005, real parameter, mass
Real VMAXLIFT	maximum possible valve lift [m]	0.02/0.03/0.085	MAS005, real parameter, higher displacement limit

Step 3: Introduce the supercomponent real global parameters shown below

Make sure that none of them is hidden.

Figure 50: Alter the external variable names

Note that you click on the Add new button to introduce each new real parameter.

Step 4: Use the VPRELOAD and VSTIFF global variables in both SPR000A spring submodels Real parameters as shown below

Figure 51: Global variables

Note that you can copy/paste from one spring to the other using the tree structure.

Figure 52: Copy/paste using the tree structure

You can do the same thing in the Explore Supercomponent window.

Figure 53: Copy/paste using the Explore Supercomponent window

A third technique is to select both springs in the tree structure or both springs in the Explore supercomponent window. This works like Common Parameters in Simcenter Amesim and you can set the values for both springs simultaneously.

Figure 54: spring values can be set simultaneously

Step 5: Using the same techniques set the VCLEAR global parameter in both LSTP00A submodels as indicated

Figure 55: VCLEAR global parameter

Step 6: For both MAS005 submodels make the modifications shown below

Figure 56: Modifications for both MAS005

Step 7: In the inlet MAS005 submodel alter the Internal variables as shown

Make the corresponding changes in the exhaust side.

Figure 57: Alter the Internal variables of MAS005

Note

3 (x2) Internal variables have had their titles altered and are not hidden anymore.

Step 8: In the inlet cam INCAM50 submodel alter the second Internal variable as shown

Do not change the exhaust side.

Figure 58: Uncheck the Hidden box for the second variable

• We have forced both cams to have a starting angle of 0. We will not be able to change this.

• We have forced the starting value of the gap or clearance in both LSTP00A submodels to be VCLEAR.

• With both cam profiles starting on a flat part, the starting values of various state variables are consistent.

Step 9: Do a Parameter mode preview and a Simulation mode preview

Figure 59: Parameter mode preview

Figure 60: Simulation mode preview

Step 10: Save the customized supercomponent as CUSVALVES50

This time specify a password, but do not forget it!

Step 11: Add the customized supercomponent to your Simcenter Amesim sketch and check that it produces the same results

Figure 61: Add the customized supercomponent to the sketch

We hope that you find using CUSVALVES50 within Simcenter Amesim more practical than the generic equivalent.

Step 12: Use the state contributions facility and also examine the .state file and .var files produced by Simcenter Amesim in an editor

State contributions facility hidden states

.var file

The important thing to realize is that things hidden by Component Customization appear under very unhelpful names (figure below). This is true even if it is not encrypted. In Component Customization you define what is private and what is public. Simcenter Amesim only shows the public part.

Figure 62: State contributions pane