"Spray B" is a three-hole Bosch injector with the same orifice specifications as Spray A. Five nominally identical 3-hole nozzles are used. The specifications are as follows:
|Specifications for Spray B injectors of the Engine Combustion Network|
|Common rail fuel injector||Bosch solenoid-activated, generation 2.4|
|Fuel injector nominal nozzle outlet diameter||0.090 mm|
|Nozzle K factor||K = (dinlet - doutlet)/10 [use μm] = 1.5|
|Nozzle shaping||Smoothed by hydro-erosion|
|Mini-sac volume||0.2 mm3|
|Discharge coefficient at 10 MPa pressure drop||Cd = 0.86 (room temperature using diesel fuel)|
|Number of holes||3|
|Hole angular position||θ = 36.4°, -62.3° and 180°|
|Orifice orientation relative to injector axis||ψ = 72.5° (145° full included angle)|
The hole of main interest has been selected to be the one drilled opposite to the fuel tube (Hole #3) . The nozzles have been designed so that the other sprays would not visually interfere with the spray of interest. Below is a schematic of the definition used for the hole orientation. The orientation angle θ represents the location of the orifice with respect to the axis of the fuel tube, the orientation angles given by the manufacturer are 36.4, -62.3 and 180 deg. for orifices 1, 2 and 3 respectively. Note that the orientation can also be expressed as φ, the angle used by the manufacturer. However, φ is referenced with two pins to hold the nozzle in position with respect to the injector body, which are not visible from outside (without unmounting the nozzle). For that reason, we defined θ as the angle between the fuel tube and the actual orifice in the counter clockwise direction when facing the injector tip.
Fig. 6.4.1 Schematical definition for the orientation of the orifices for Spray B (145° included angle 3-hole nozzle). The hole of interest for Spray B is the opposite to the fuel tube (hole #3).
The close-up view of the tip actually shows the position of the three orifices with respect to the fuel tube to observe that the hole of interest (hole #3) is somewhat isolated to the other two orifices to enable more complete optical access.
Orifice exit boundaries (measured via optical microscopy) are provided in the table below as text files (*.txt). The orientation of the coordinate system for the exit boundary imaging is now described. Images were obtained orthogonal to the hole axis in order to focus on the exit boundary. Beginning with hole 3, the hole of interest, images were obtained with the very tip of the injector at the left and the injector body at the right, meaning that the image x axis (x') is in the same plane as the fuel tube (the x-y plane in Fig. 6.4.1) for hole 3. Keeping the optical system fixed, the injector was then rotated to bring the other holes into focus. As a result, the left of the image (-x' direction) is always towards the tip of the injector (+x direction in Fig. 6.4.1).
|Injector Serial #||Measured Diameter||Exit boundary|
|211196||H1:91.3μm; H2:91.5μm; H3:90.8μm||H1 H2 H3|
|211198||H1:92.0μm; H2:91.7μm; H3:91.5μm||H1 H2 H3|
|211199||H1:90.9μm; H2:91.7μm; H3:90.9μm||H1 H2 H3|
|211200||H1:90.3μm; H2:90.3μm; H3:93.2μm||H1 H2 H3|
|211201||H1:90.2μm; H2:91.5μm; H3:93.8μm||H1 H2 H3|