A Comparative Study of the Fuel Pressure and Temperature Effects on the GDi Multi-Hole Spray

The gasoline direct injection (GDi) engine cold-start emissions of unburned hydrocarbons (UHC) and particulate emissions, prior to the full catalyst warm-up, are a substantial source of engine emissions and the primary challenge to meet the Euro6D and US Tier5 emission regulations. Figure 1 presents typical accumulated particulate emissions from a GDi engine, with homogeneous combustion operation, under the new European drive cycle (NEDC). It illustrates the large proportion of particulate emissions during the engine cold-start phase.