Multidimensional simulation of the air-flow and fuel transport process in the air-assisted injection system of a new, low-emission two-stroke engine

The aim of this work is to model the air and fuel flow process in the air-assisted injection system of a new, low emission two-stroke engine with a view to determine the critical features in the system that influence the engine performance. A computational method for multidimensional, compressible, two-phase flow using a Lagrangian-Eulerian approach is developed and used for this analysis. Good agreement is observed between computations and measurements of fuel consumption and pressure recovery in the injection system of the current prototype. The results show a strong dependence of the typical air flow characteristics of the injection system on engine speed. Significant fuelling after inlet port closure, higher fuel transport efficiency at low speeds and a substantial impingement of liquid fuel on the solid walls of the injection system are also evident from the results of the computations. This suggests a delayed transient response and strong speed dependence of the quality of mixture preparation in this system, which explains certain observed trends in the current prototype of the engine