Development of MGE 1.8T combustion system assisted by numerical simulation

摘要

This paper describes the CFD assisted combustion system development for a 1.8 L turbo GDI engine which has been developed by SAIC Motor. The combustion system is a direct injected turbocharged system employing centre-mounted multi-hole injectors. The in-cylinder charge motion, fuel injection, air/fuel mixing and combustion processes in the combustion system were evaluated. Proposed intake port options were numerically investigated and compared. Impingement of fuel droplets on piston crown, and wetting on the walls of combustion chamber and the subsequent impacts on mixture formation and oil dilution were investigated by both CFD tool and engine test approaches. Spray targeting was optimised to minimise oil dilution, and multiple fuel injection strategies were investigated to understand its impact on injection, mixture formation and combustion process. The concentrations of pollutants including CO, NO_x, HC and soot were simulated. The present simulation results agree well with the measurement data from engine testing, including cylinder gas pressure.