Simulation of Self Ignition in HCCI and Partial HCCI Engines Using a Reduced Order Model

In this paper, a newly developed model that can be applied for the prediction of ignition delay times and heat release in engines operating in Homogeneous Charge Compression Ignition (HCCI) mode is presented. The proprietary numerical model is based on multi-zone application of the First Law of Thermodynamics and is coupled with a newly developed reduced kinetic schemes describing the oxidation of primary reference fuels (n-Heptane and iso-Octane). This proprietary code takes into account the influence of inhomogeneities of residual gas, air-to-fuel ratio and temperature distribution on combustion processes in a simplified fashion.

The proposed reaction schemes are validated by comparison with shock-tube measurements of ignition delay times at various pressures, fuel-to-air ratios and temperatures. Furthermore, the performance of reduced models are tested by comparing the results with predictions of detailed reaction mechanisms which are available in the literature.

CHEMKIN solver has been coupled with MATLAB in order to solve the chemistry and to calculate the heat release during the compression stage.

Simulations of combustion processes using different fuels at various operating points and engines (gasoline, diesel) show good agreement with experimental observations.