Numerical simulation on multi-injection nozzle applied to Ignition Chamber GDI engine 2007-01-1910

Operating with a single, fixed ignition location imposes very stringent requirements on the mixture preparation process in GDI engines, because it is very difficult to provide a combustible mixture at the spark gap when spark plug discharges over the entire engine operating range [1]. A new GDI combustion system called Ignition Chamber Gasoline Direct-Injection combustion system is developed to solve this problem. In this combustion system, a multi-injection nozzle that provides a constant volume spray plume from a nozzle hole is adopted to maintain the constant air/fuel ratio in the ignition chamber.

Numerical simulations of the multi-injection process were carried out, and the spray patterns formed by the constant nozzle hole and the major nozzle holes with various effective plunger strokes were calculated. Based on the simulation results, the parameters that impact the performance of the multi-injection nozzle were analyzed and appropriate nozzle dimensions for the Ignition Chamber GDI engine were determined. The 1-D results showed that using multi-injection nozzle can maintain the constant nozzle hole delivery volume at various fuel delivery volumes per cycle per cylinder and meets the requirement of the Ignition Chamber GDI engine combustion system, and 3-D simulation results showed that leakage from constant nozzle hole is at an acceptable level.