Calibrating Tables in a Tradeoff Calibration

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Procedure For Calibrating Tradeoff Tables Setting Values of Other Variables Determining a Value at a Specific Operating Point Tradeoff Table Menus

Procedure For Calibrating Tradeoff Tables

Selecting a table node in the tree display enables you to view the models that you have displayed and calibrate that table.

To calibrate the tables,

1. Select the table that you want to calibrate.

2. Highlight one operating point from the table.

3. Set the values for other input variables.

   For information, see Setting Values of Other Variables.

4. Determine the value of the desired operating point.

   For instructions, see Determining a Value at a Specific Operating Point.

5. Click to apply this value to the lookup table.

   This automatically adds the point to the extrapolation mask.

6. Repeat steps 2, 3, 4, and 5 at various operating points.

7. Extrapolate to fill the table by clicking   in the toolbar.

   For information, see Filling the Table by Extrapolation.

8. You can also edit table cell values manually by typing values, or right-click to Copy or Paste values.

After you complete all these steps you can export your calibration. For information, see Exporting Calibrations.

Notice that the graphs colored green indicate how the highlighted table will be filled:

• If a row of graphs is highlighted, the table is being filled by the indicated model evaluation (the value shown at the left of the row).

• If the column of graphs is green, the table is being filled by the indicated input variable (shown in the edit box below the column).

The next sections describe the following in detail:

• Setting Values of Other Variables

• Determining a Value at a Specific Operating Point

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Setting Values of Other Variables

Typically the models that you use to perform a tradeoff calibration have many inputs. When calibrating a table of just one input, you need to set values for the other inputs.

Setting Values for Individual Operating Points

To set values for inputs at individual operating points,

1. Highlight the operating point in the lookup table.

2. Use the edit boxes or drag the red bars to specify the values of the other variables.

In the preceding example, the spark table is selected (the SPK graph is colored green). You have to specify the values of AFR (A) and EGR (E) to be used, for example:

1. Select the spark table node.

2. Click in the edit box for A and set its value to 14.3.

3. Click in the edit box for E and set its value to 0.

The default values are the set points of variables, which you can edit in the Variable Dictionary.

Setting Values for All Operating Points

For example, if you are using a tradeoff to calibrate a table for spark angle, you might want to set the initial values for tables of air/fuel ratio (AFR) and exhaust gas recycling (EGR).

To set constant values for all the operating points of one table,

1. Highlight the table in the tree display.

2. Select one operating point in the table.

3. Enter the desired value of the cell.

4. Right-click and select Extrapolation Mask > Add Selection.

   This adds the cell to the extrapolation mask.

5. Click to extrapolate over the entire table.

This fills the table with the value of the one cell.

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Determining a Value at a Specific Operating Point

Performing a tradeoff calibration necessarily involves the comparison of two or more models. For example, in this case, the tradeoff allows a calibrator to check that a value of spark that gives peak torque also gives an acceptable value for the NOX flow model.

1. To select a value of an input, do one of the following:

   • Drag the red line.

   • Right-click a graph and select Find the minimum, maximum, or turning point of the model as appropriate (also in the toolbar and Inputs menu).

   • Click the edit box under the graph as shown above and enter the required value.

2. Once you are satisfied with the value of your variable at this operating point, you apply this value to the table by doing one of the following:

   • Press Ctrl+T.

   • Click (Apply Table Filling Values) in the toolbar.

   • Select Tables > Apply > Fill to Table.

Right-Click Menu

Right-clicking a graph enables you to

• Find minimum of model output with respect to the input variable

• Find maximum of model output with respect to the input variable

• Find turning point of model with respect to the input variable

  These first three options are also in the Inputs menu.

• Reset graph zooms (also in the View menu)

There are also toolbar buttons to find the minimum, maximum and turning point of the selected model graph.

Using Zoom Controls on the Graphs

To zoom in on a particular region, shift-click or click with both mouse buttons simultaneously and drag to define the region as a rectangle.

To zoom out to the original graph, double-click the selected graph, or use the right-click Reset Graph Zooms option (also in the View menu).

Note   Zooming on one graph adjusts other graphs to the same scale.

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Tradeoff Table Menus

View Menu

Selecting the View menu offers you the following options:

• Table History

  This opens the History display. For information, see Using the History Display.

• Configure Hidden Items

  This opens a dialog box that allows you to show or hide models and input variables. Select or clear the check boxes to display or hide items. This is particularly useful if you are trading off a large number of models or models that have a large number of factors.

• Display Confidence Intervals

  When you select this, the graphs display the 99% confidence limits for the models.

• Display Common Y Limits

  Select this to toggle a common y-axis on and off for all the graphs. You can also press CTRL+Y as a shortcut to turn common Y limits on and off.

• Display Constraints

  Select this to toggle constraint displays on and off. Regions outside constraints are shown in yellow on the graphs, as elsewhere in the toolbox.

• Graph Size

  Select from the following options for number and size of graphs:

  • Display All Graphs

  • Small

  • Medium

  • Large

• Large Graph Headers

  Select this to toggle graph header size. The smaller size can be useful when you need to display many models at once.

• Reset Graph Zooms

  Use this to reset if you have zoomed in on areas of interest on the graphs. Zoom in by shift-clicking (or clicking both buttons) and dragging. You can also reset the zooms by double-clicking, or by using the right-click context menu on the graphs.

• Display Table Legend

  Select this to toggle the table legend display on and off. You might want more display space for table cells once you know what the legend means. The table legend tells you how to interpret the table display:

  • Cells with a tick contain saved values that you have applied from the tradeoff graphs (using the 'Apply table filling values' toolbar or menu option).

  • Yellow cells are in the extrapolation mask.

  • Blue cells are in a region mask.

  • Yellow and blue cells with rounded corners are both in a region and the extrapolation mask.

  • Cells with a padlock icon are locked.

Tables Menu

• Apply Fill to Table

  Select this option to apply the values from the tradeoff graphs to the selected table cell. This option is also in the toolbar, and you can use the keyboard shortcut CTRL+T.

  Note that the corresponding cell in all tables is filled with the appropriate input, not just the cell in the currently displayed table. For example if you have graphs for spark and EGR inputs, selecting Apply Fill to Table fills the spark table cell with the spark value in the graphs, and the EGR table cell with the EGR value.

• Extrapolation Mask — Also available in the toolbar and the context menu (by right-clicking a table cell). Use these options to add and remove cells from the mask for filling tables by extrapolation. Note that cells filled by applying values from the tradeoff graphs (using the Apply Fill To Table toolbar and menu option) are automatically added to the extrapolation mask.

  • Add Selection

  • Remove Selection

  • Clear Mask

• Extrapolation Regions — Also available in the toolbar and the context menu (by right-clicking a table cell). Use these options to add and remove cells from regions. A region is an area that defines locally where to extrapolate before globally extrapolating over the entire table. Use regions to define high-priority areas for use when filling tables by extrapolation. See Using Regions.

  • Add Selection

  • Remove Selection

  • Clear Regions

• Extrapolate — This option (also in the toolbar) fills the table by extrapolation using regions (to define locally where to extrapolate before globally extrapolating) and the cells defined in the extrapolation mask.

• Extrapolate (Ignore Regions) — This option fills the table by extrapolation only using cells in the extrapolation mask.

• Table Cell Locks — Also available in the context menu by right-clicking a table cell. Use these options to lock or unlock cells; locked cells are not changed by extrapolating.

  • Lock Selection

  • Unlock Selection

  • Lock Entire Table

  • Clear All Locks

Inputs Menu

• Reset to Last Saved Values — This option resets all the graph input values to the last saved value. Also in the toolbar.

• Set to Table Value — This option sets the appropriate input value on the graphs to the value in the table.

The following three options are only enabled if a graph is selected (click to select, and a blue frame appears around the selected graph). They are also available in the right-click context menu on the graphs.

• Find Minimum of model vs input factor

• Find Maximum of model vs input factor

• Find Turning Point of model vs input factor

  where model and input factor are the model and input factor displayed in the currently selected graph, for example, TQ_model vs Spark.

• Automated Tradeoff — Use this option once you have set up an optimization, to apply that optimization to the selected region of your tradeoff table. See Automated Tradeoff for information.

Tools Menu

• Calibration Manager — opens the Calibration Manager. See Calibration Manager.

• Surface Viewer — Opens the Surface Viewer. See Surface Viewer.

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Setting Up a Tradeoff Calibration

Using Regions

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