Influence of thermal barrier coating on partially premixed combustion in internal combustion engine

Abstract

Nowadays, improving the thermal efficiency of internal combustion engine (IC Engine) has becoming increasingly essential. In this paper, the influences of thermal barrier coating (TBC) on the near wall combustion and pollutant distribution in Gasoline/Diesel RCCI (Reactivity Controlled Compression Ignition) and GCI (Gasoline Compression Ignition) combustion are investigated. Mathematical model of TBC is applied in Kiva3v CFD code for the numerical investigation, and GCI experiments is conducted for the real engine tests. The result shows that for Gasoline/Diesel RCCI combustion, spray/wall impingement is observed resulting in fuel film which becomes the main source of near wall soot formation. While for GCI combustion, no film is found and most of the pollutants are concentrated in the bowl region. A thermal reorganization effect is found with TBC, which not only keeps higher near wall temperature for the chemical reaction, but also enlarges the bowl-center high temperature area. By applying TBC, the thermal efficiency can be improved for both combustion modes. Higher peak pressure and advanced combustion phase are also produced which accelerate the boundary combustion especially in the squish region, therefore both unburned products and soot can be reduced at the cost of increased NOx emission.