Overview
Ignition Fundamentals for Internal Combustion Engines with low CO2 emissions respecting the most stringent emission regulations.
Two major technologies to reduce CO2 emissions are the use of high EGR levels to increase the compression ratio and reduce the knock sensitivity and the stratified combustion. A limiting parameter for these combustion modes is the stability of the ignition. The ignition requirements are very much dependent on the combustion system considered. The size and the duration of the spark and the temporal evolution of the energy transferred into the gas are major parameters to be controlled.
One most important topic is the understanding of the energy path from the power electronics through the spark until the combustion initiation.
FAMAC is a research project which aims to understand the physics of the initial arc, the heat and radical transfer into the ignitable gas and the initialisation of the chemical combustion process using an approach integrating different levels of modelling, simulation and experimental validation. At the end, the project should allow to identify the physical key parameters for the design of future ignition systems.
The aim of FAMAC is the understanding of the physics of the arc integrating different levels of modelling, simulation and experimental validations.
The project includes three highly linked tasks, each with a simulation and an experimental approach:
- Characterisation and validation of the ignition requirements in a transparent single cylinder engine
- Fundamental research using a simplified geometry
- Fundamental research using a more complex geometry
Funding
Results
The main results so far are:
- The characterisation of the thermodynamic and aerodynamic conditions during the ignition phase in the engine.
- The evaluation of different ignition systems in terms of ignition stability for two different engine operating points with a variation of air and EGR dilution.
- The documentation of the fact that the main parameter limiting the dilution for these operating points is the total energy supplied independent of the spark duration (ns to ms) and the number of spark breakthroughs.
- The supply of a database for the thermodynamic and transport properties at extremely high temperatures (<50000K) for air and the ignitable mixture.