Diesel Injector Fuel Injector 0445110522 Bosch for Chrysler Jeep Grand Cherokee, jeep Grand Cherokee Iv, dodge, maserati, vm Motor

The effect of nozzle diameter, injection pressure and ambient temperature on spray characteristics in diesel engine  (part 1)

1. Introduction

Fuel injected into the chamber is important to the diesel engine because it influence the performance and emission. During combustion, a spray is simply the introduction of liquid into a gaseous environment through a nozzle such that the liquid, through its interaction with the surrounding gas and by its own instability, breaks-up into droplets [1]. Spray characteristics is known to significantly affect the combustion and emission processes in diesel engines. By optimizing spray characteristics, the raw emissions from the diesel engine which are mainly NOx and PM can be minimized [2-4]. Investigations into diesel sprays characteristics have concentrated on the effect of the spray characteristic on engine performance such as the spray tip penetration, break-up length and droplet size and velocity distributions [5].The injection pressure has significant effect on spray liquid penetration [6]. The spray tip penetration gets longer as the injection pressure increases. This result is related to both higher quantity and higher velocity of the droplets at higher injection pressures [7]. Proportional to injection pressure, the spray penetrates faster at higher injection pressures [8]. The break-up length characterizes a point of discontinuity, where the spray changes from a zone of liquid (bulk liquid, or interconnected ligaments and droplets), to a finely atomized regime of droplets [9]. After the disintegration of the liquid column emerging from the nozzle, the generated droplets may further break-up into smaller ones as they move into the surrounding gas [10]. Development of this deformation leads to break-up into smaller droplets.

The forces associated with dynamic pressure, surface tension and viscosity control the break-up of a drop [11-12]. However, CFD is a compromise tool being used to predict the critical part that cannot be done in experiment. In this research, the characteristics of spray diesel are investigated focusing on changing ambient temperature, injection pressure with the different nozzle diameter by using Computational Fluid Dynamics. This simulation can capture droplet diameter, spray penetration and breakup length.