| CAGE User's Guide | |
Calibrating Lookup Tables Using CAGE
There are two different types of calibration that you can perform using CAGE:
Feature Calibration
A feature calibration compares a model of an estimated signal with a lookup table (or algebraic collection of tables) which estimates the same signal in the ECU. CAGE finds the optimum calibration for the lookup table(s).
For example, a typical engine subsystem controls the spark angle to produce the peak torque; that is, the Maximum Brake Torque (MBT) spark. Using the Model Browser, you can build a statistically sound model of MBT spark, over a range of engine speeds and relative air charges, or loads. Use the feature calibration to fill a lookup table by comparing the table to the model.
Tradeoff Calibration
A tradeoff calibration fills lookup tables by comparing models of different engine characteristics at key operating points.
For example, there are several models of important engine characteristics, such as torque and Nitrogen Oxides (NOx) emissions. Both models depend on the spark angle. At a particular operating point, a slight reduction of torque may result in a dramatic reduction of NOx emissions. Thus, the calibrator uses the value of the spark angle that gives this reduction in NOx emissions in favor of the spark angle that generates maximum torque.
Comparing Calibrations to Data
You can compare your calibrations to experimental data, for validation.
For example, after completing a calibration, you can import experimental data from a spreadsheet. You can use CAGE to compare your calibration to the data.
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