"Spray A" Operating Condition

The ECN working group has identified a few experimental conditions that will be the focus of modelers and experimentalists who wish to voluntarily participate in the ECN in the future. The experimental collaboration is made possible by the donation of "identical" injection systems by Robert Bosch LLC. The ECN group has agreed to experiment at the same injector and ambient conditions, thereby leveraging the expertise of each participant, and enabling direct comparison between different facilities. We expect that the dataset developed will become a serious focal point for model validation and further advanced diagnostics.

Specifications for the injector and ambient operating conditions for this "Spray A" condition are given below but recommendations for parametric variation beyond Spray A are also available. The Spray A condition is a low-temperature combustion condition relevant to engines that use moderate EGR. The injector specifications are for modern advanced injection systems with high pressure capability. As a prerequisite to using these injectors, ECN participants are expected to measure the boundary conditions (e.g. temperature, pressure) for the ambient and injector quantitities, and state uncertainties associated with the boundary conditions and other data. Please contact Lyle Pickett if you believe you can meet these boundary conditions and would like to use one of the shared injectors.

If seeking to match only the injector specifications while operating at room temperature for the ambient gases, care should be taken to match the ambient density specification, as this primarily determines the spray mixing and penetration rate.



Specifications for Spray A operating condition of the Engine Combustion Networka
Ambient gas temperature 900 K
Ambient gas pressureb near 6.0 MPa
Ambient gas densityb 22.8 kg/m3
Ambient gas oxygen (by volume) 15% O2 (reacting); 0% O2 (non-reacting). (look here for CO2 and H2O and N2 %)
Ambient gas velocity Near-quiescent, less than 1 m/s
Common rail fuel injector Bosch solenoid-activated, generation 2.4
Fuel injector nominal nozzle outlet diameter0.090 mm
Nozzle K factor K = (dinlet - doutlet)/10 [use μm] = 1.5
Nozzle shaping Hydro-eroded
Mini-sac volume 0.2 mm3
Discharge coefficient Cd = 0.86, using 10 MPa pressure drop and diesel fuel
Number of holes 1 (single hole)
Orifice orientation Axial (0° full included angle)
Fuel injection pressure 150 MPa (1500 bar), prior to start of injection
Fuel n-dodecanec
Fuel temperature at nozzled363 K (90°C)
Common raile GM Part number 97303659. Used by 2005-2006 Duramax engines.
Common rail volume/length 22 cm3/28 cm
Distance from injector inlet to common rail24 cm
Tubing inside and outside diametersf Inside: 2.4 mm. Outside: 6-6.4 mm.
Fuel pressure measurement 7 cm from injector inlet / 24 cm from nozzle
Injection duration 1.5 ms
Injection mass 3.5 - 3.7 mg
Approximate injector driver current 18 A for 0.45 ms ramp, 12 A for 0.345 ms hold
Access experimental data Click for Spray A experimental data search

a from SAE Paper 2010-01-2106
b This exact combination of ambient pressure and density corresponds to a particular set of gases for a 0%-O2 condition with 89.71% N2, 6.52% CO2, and 3.77% H2O by volume and a compressibility factor, Z = 1.01. When different gases are used, the pressure must vary to maintain the same density
c Chosen as a fluorescence-free diagnostics fuel with known chemistry and properties. Other fuels may be selected after initial study and comparison.
d May be slightly different than injector body temperature
e Use rail outlet farthest away from fuel entrance (small orifice) to rail (i.e. cylinder #1).
f This 24 cm tube is available for purchase from USUI, reference part number IFP01-0000094716. It is rated for 2500 bar pressure.

Further requirements for injector usage
Because of concerns about nozzle aging the following precautions shall be taken when using the injectors: