A COMPUTATIONAL STUDY OF INTRA-CYCLE RECIRCULATION OF PARTIAL OXIDATION PRODUCTS (RePOx) FOR IC ENGINE COMBUSTION CONTROL

摘要

This work examines the potential for using intra-cycle recirculated partial oxidation products (RePOX) to control the phasing of advanced IC engine combustion systems such as HCCI. The products are created by extracting a portion of the lean charge products during the expansion stroke and mixing these with fuel in an auxiliary chamber. The equivalence ratio(Θ) of the recirculated reactants is controlled by varying the amount of mass extracted. The recirculated products are then reintroduced into the main charge in order to accelerate the main chamber reaction. This process is modeled using the CHEMKIN-PRO software package combined with an external program to balance mass and energy for the RePOX system. n-Heptane, modeled with the detailed mechanism developed by Lawrence Livermore National Laboratory, is used as the fuel. The effects of extraction mass, extraction timing and injection timing on combustion phasing and engine efficiency are examined and found to have significant effect on flammability limits and combustion phasing, indicating the RePOx concept could possibly be used to control HCCI and derivative IC engine combustion systems.