CAGE User's Guide

Filling Table Values

This tool fills the table with the values of the model at the operating points specified in your normalizers.

To fill the table values by reference to the model:

• Click  or select Table -> Fill.

How CAGE Fills Tables

CAGE fills tables in a feature calibration by rearranging the equation model = strategy.

Example

A very simple example strategy for torque might consist of two tables:

• A speed-load (or relative air-charge) table filled with values of torque
• An air-fuel ratio (AFR) modifier table to account for the behavior of AFR

  

This example is a strategy with a base speed-load (N, L) table for torque and a modifier table to account for the behavior of AFR (A). Your strategy might use several speed-load tables for different values of AFR, or as in this case you might use an AFR table as a modifier to add to a single speed-load table to adjust for the effects of different AFR levels on your torque output.

• -

With the tables arranged in the following manner, this is the feature equation:

To fill the speed-load table, the equation is rearranged to

If the AFR modifier table (T2) is initialized with 0s, this becomes

• or

Each cell in the table is therefore filled with the corresponding values of the model at the operating point specified by the breakpoints.

For example, to fill the T1 cell (Speed = 2500, Load = 0.5), CAGE evaluates the model at Speed = 2500, Load = 0.5, and uses the value of AFR that you choose in the dialog that appears.

You can choose one value of AFR for the whole table (for example, 14.3), or you can choose a range of values and fill using the average model value at each cell. For example, if you choose AFR = 11, 13, 15, the model is evaluated at all three values for each cell and the average model value is used. The default AFR value is the set point (which you can set in the variable dictionary).

Note    To fill using model values averaged over a range of an input variable, you type the minimum and maximum (separated by a space) in the Range edit box, and the number of desired points in the Points edit box.

When the base table (T1) is filled, CAGE rearranges the equation again to fill the modifier table (T2):

For example, to fill the T2 cell at AFR = 12.5, you choose values of speed and load (such as 3000,0.4) and CAGE evaluates the following:

As before, you can choose a range of values for speed and load and use the average to fill the table.

Note    Be careful not to initialize modifier tables with 0 if they are multipliers in your strategy. In this case, solving for T1 gives , and you cannot divide by zero. This operation will fail.

Solving algebraically for a table in the strategy is not always possible. In these cases you must use optimization.

Initializing Table Values

Optimizing Table Values