Optimization of New Advanced Combustion Systems Using Real-Time Combustion Control

Due to stricter fuel consumption and emissions requirements new gasoline engine concepts using advanced combustion systems such as fully variable valve train and controlled auto-ignition (HCCI) become important.

Classical generic methods developed for system optimization with an increased number of variabilities (e.g. DoE - Design of Experiments), need extensions, because closed loop control is required for critical system parameters like valve train actuation and combustion behavior.

This paper describes a new approach called “controlled optimization”, which is an extension of DoE using real-time controllers for critical system parameters (e. g. combustion timing). This ensures stable engine operation and protection under all conditions. Less critical parameters are still used as simple DoE-set values. Combustion timing, directly related to spark advance in conventional gasoline engines, is also strongly influenced by valve timing parameters. Consequently this has a direct representation in the combustion controllers structure. ECU-structures for advanced combustion systems are still under development. Using “controlled optimization” leads to significant benefits in this area, because deep insight concerning parameter effects, interactions and controller structures can be obtained in a short time.