A Detailed Reaction Kinetics-Based Calculation Tool for Internal Combustion Engine-Related Ignition Processes 2022-01-5050

Ignition delay times are major information needed to allow the simulation of auto-ignition and knocking combustion in internal combustion engines (ICEs). Due to their variance over changing boundary conditions (BC) and limitations of measurement processes, a common way to obtain them is via reaction kinetic simulations. To facilitate and accelerate the simulation process with varying operating conditions and gas composition definitions, an efficient tool that uses Cantera’s Python interface has been created. It allows the end-user to easily calculate the ignition delay data needed for engine simulation without the necessity for in-depth knowledge of the underlying processes. All calculations are based on the creation of a homogeneously mixed gaseous mixture corresponding to engine-based environmental conditions. Depending on the desired fuel, oxidizer, temperature, pressure, water, and exhaust gas recirculation (EGR) rate, the resulting reactant composition is computed. From there, the mixture is ignited in a constant-pressure (optional: constant-volume) reactor, and the result is evaluated with all popular ignition delay definitions. The whole concept is modular and can be easily expanded with alternative EGR and/or ignition delay definitions. Two more sophisticated additions are shortly mentioned and explained. First, the view on incomplete combustion caused by finite residency times (reflecting real engine operation). This approach results in additional nitrogen oxides (NO_X) in the recirculating exhaust gas and thus lowers the ignition delay times. Second, the admixture of lubricant oil contained in charge air. With this, the effects of externally added long-chained hydrocarbon molecules on, for example, methane (CH₄) combustion, can be addressed.