Distribution of the Fuel Flow in a Cold Start System Using an Electronic Fuel Injector 2007-01-2706

Cold start systems provide the introduction of gasoline inside the engine intake system during cold start and warm-up acceleration, as ethanol fuel shows engine operation difficulties at low temperatures. Despite the technological evolution, traditional cold start systems may present problems mainly related to flow control and gasoline distribution to the engine cylinders hindering cold start and warm-up operation with the increasing of emissions levels and fuel consumption. The cold start system used allows for simultaneous gasoline introduction through calibrated orifices in the four conduits of the intake system. Adjustment of gasoline flow is made by an electronic fuel injector. The objective of this work is to analyze numerically and experimentally the gasoline flow in an auxiliary cold start system for vehicles with engines using ethanol or ethanol-gasoline blends (flex fuel). Computational fluid dynamics made possible to determine the calibrated hole diameters for more efficient pulverization and uniform distribution of gasoline to the engine cylinders.