Research of Exhaust Gas Recirculation on Commercial Turbocharged Gasoline Direct Injection Engine With Intense Tumble Flow

The application of exhaust gas recirculation (EGR) technology on gasoline direct injection (GDI) engines can suppress knocking, reduce fuel consumption, and reduce NO_x emissions. The effects of EGR with enhanced intake tumble flow, on the combustion phase, combustion duration, knock index and combustion cycle variation of the engine, were studied at two speeds of 1500 r/min and 2000 r/min from low to medium and to full load. The research shows that although the commercial engine has been well calibrated and optimized, the optimization of EGR and enhanced tumble flow together with the optimization of the ignition angle can improve the engine's economy and emission characteristics, while maintaining relatively fast burning speed and low combustion cycle variation. From medium to heavy load, the economy can be improved by 2.6–10%, and the minimum fuel consumption can be reduced to 213 g/kW. h. Under heavy load conditions (brake mean effective pressure (BMEP) more than 14 bars), power performance deteriorates due to insufficient boost performance. The 5–20% EGR rate brings 10% power loss. EGR combined with tumble intake has a significant effect on reducing the engine's NO_x and CO, with average reductions of 60% and 22%, but HC increased by 32%.