Modeling of emissions from HCCI engines using a consistent 3-zone model with applications to validation of reduced chemistry

Abstract The piston crevice and the quench zone, the area of fluid close to the cylinder walls, are responsible largely for emissions in Homogeneous Charge Compression Ignition (HCCI) engines. For proper modeling of emissions from HCCI engines, the piston crevice and quench zone need to be included in the numerical model. For HCCI applications, we have developed an improved numerical model with three zones: the piston crevice zone, the quench zone close to the cylinder walls, and the cylinder zone comprising up of the rest of the cylinder. With the assumption of equal pressure for all zones, an analytical model is developed for the mass transfer between the core fluids and those in the piston crevice. The numerical model then solves for the coupled mass, energy, and species equations simultaneously leading to consistent solutions at every time step. Comparisons of the calculated results are made between this stand-alone multi-zone code, a 3-D CFD model coupled with multiple zones, and experimental data which show encouraging agreement. The present stand-alone model also provides a useful platform for development/validation of reduced chemistry for emissions.