Today’s combustion process control depends on external measured data e.g. engine speed, rail pressure, air mass flow, however it is the state of cylinder charge conditions of intake and the injection parameters that basically determine the start and propagation of combustion.
There are basically two conceivable approaches to acquire the state of combustion. One is a direct observation the process by measurement e.g. by using cylinder pressure sensors. (CYPRESS™)
The other approach is that of a model-based combustion calculation, based on current charge states and injection parameters. (MMCD)
With “EmIQ Control“, a cylinder pressure based combustion position detection and closed loop combustion control has been developed by AVL for enabling the successful transient use of alternative combustion on a single cylinder research engine.
This measure of control allows to adjust the combustion process by the real in-cylinder conditions. In addition it can be used to keep series emission tolerances low and stable in the long run.
The concept was successfully adapted and extended for enabling application to multi cylinder engines.