Objective Determination of Minimum Engine Mapping Requirements for Optimal SI DIVCP Engine Calibration 2009-01-0246
In response to marketplace demand for increased engine performance and economy, spark-ignition (SI) engine applications with dual-independent variable cam-phaser actuators (DIVCP) are now commonplace.
In this paper, the minimum number of test measurements required to optimally calibrate the steady-state spark advance and cam-phaser settings of a SI DIVCP engine was determined, using a high-fidelity model of a 2.2L SI DIVCP engine with predictive combustion capability as a basis.
A calibration development process was designed to objectively determine the minimum number of torque vs. spark advance sweeps required for the SI DIVCP engine.
First, Torque production results from calibration tables based on cost-feasible sets of 52, 96, 173, 250, 329, and 406 sweeps were determined. Next, calibration reference tables were developed from an exhaustive data collection process based on 10,000 sweeps. Finally, torque results from the cost-feasible calibrations were compared to the torque results from the exhaustive reference calibrations tables to determine the minimum number of sweeps required to match the results of the exhaustive approach.