The Application of Design of Experiment and Multi Variable Optimisation to Cold Starting in an Automotive SI Engine

This paper describes the process used to characterise an exhaust after treatment designs while using spark retard and lean fuel operation during a cold start on a Euro 96 drive cycle using a dynamic dynamometer to simulate a vehicle. It is well understood that spark retard and lean fuel operation achieve faster catalyst light off times but usually at the cost of driveability. This study defines the operating envelope for both reduced emissions and vehicle driveability.

A design of experiment methodology was employed to characterise the system and produce models that were used to perform a trade off between driveability and reduced emissions for a given hardware configuration. Statistical techniques were utilised to select the best vehicle calibration