As a part of the project, the homogeneous reactivity-controlled compression
ignition (hRCCI) concept is being investigated along with the development of
0D/1D combustion simulation models. The proposed concept employs early direct
injection of octanol as the high-reactivity fuel in combination with port fuel
injection of ethanol as the low-reactivity fuel. In the previous parts of the
publication, testing results and the in-cylinder fuel and temperature
distribution predictions were studied. Low-temperature combustion (LTC) concepts
such as hRCCI are strongly governed by autoignition chemistry of the fuels and
oxidizer, making the explicit consideration of chemical kinetics essential for
predictive simulations. In addition, the hRCCI combustion process exhibits high
sensitivity to a wide range of control parameters, including intake temperature,
intake pressure, excess air ratio, premixed fuel ratio, and direct injection
parameters, posing further challenges to model robustness.
To address these challenges, a predictive and robust quasi-dimensional multi-zone
combustion model for LTC engines is developed. The model couples a 0D/1D flow
framework implemented in GT-POWER with detailed chemical kinetics solved using a
Python–Cantera interface for user-defined combustion modeling. The combustion
framework incorporates dedicated sub-models to account for fuel evaporation,
interzonal heat transfer, wall heat transfer, spatial distribution of directly
injected octanol, and temperature stratification across the zones. The model’s
predictive capability is validated against experimental data from a
single-cylinder research engine under variations in intake pressure, intake
temperature, premixed ratio, and the start of direct octanol injection. The
simulation results show strong agreement with experimental measurements,
demonstrating the robustness and predictive accuracy of the developed modeling
approach. The proposed simulation framework provides a valuable tool for the
future development and optimization of low-temperature combustion engine
concepts aimed at improving efficiency and reducing emissions.
