Abstract:

 The effects of deep Miller cycle (DMC) on fuel consumption, power and emissions were invest- igated to reduce the fuel consumption of an 2.0-L in-line four cylinders gasoline direct injection (GDI) original engine by simulation and experiment. The cam lift , phase position and higher compression ratio (CR) for DMC were optimized wih one-dimensional simulation software, and the tumble motion and atomization characteristic were analyzed with computational fluid dynamics (CFD) software, and the effects of DMC on combustion performance, pumping mean effective pressure (PMEP), brake specific fuel consumption (BSFC), power, emission and others were investegated with design of experiment (DOE). The results showed that the fuel consumption of the engine were greatly reduced in the middle and small load areas by using the DMC. The fuel consumption of the vehicle with the engine were reduced 4.1% under the New European Driving Cycle (NEDC) by the ananlysis with the one-dimensional simulation.

Key words: turbocharged gasoline direct injection engine , deep Miller cycle (DMC), high com pression ratio, pumping mean effective pressure , fuel consumption , New European Driving Cycle (NEDC)