A Physics-Based Integrated Model of a Spark Ignition Engine and a Three-Way Catalyst

Abstract

This article proposes an integrated model of a spark ignition engine, the exhaust system, and a three-way catalyst. The model can calculate instantaneous fuel consumption, as well as CO, NO, and HC tailpipe emissions under transient driving conditions. Where practical, this model is based on physical principles to improve its portability and reduce the calibration required. The model is calibrated using fully warm, steady state engine maps and the results of a single transient test of the engine and exhaust system. It is then validated over the New European Drive Cycle and cold start Extra Urban Drive Cycle.

Tradeoffs between model accuracy and model complexity are then examined by progressively reducing the order of the proposed model. The accuracy of some lower-order model formulations is shown to be acceptable, suggesting that such a model may be sufficiently fast and accurate for use in dynamic optimization.

Keywords:

• Automotive emissions
• Cold start
• Experimental measurement
• Internal combustion engines
• Numerical simulation
• Reduced order models

ACKNOWLEDGMENTS

This research was supported by the Advanced Centre for Automotive Research and Testing (ACART, www.acart.com.au), the Ford Motor Company of Australia, and Australian Research Council Grants FT0991117 and FT100100538.