Evaluation of Shot-to-Shot In-Nozzle Flow Variations in a Heavy-Duty Diesel Injector Using Real Nozzle Geometry

Torelli, Roberto; Matusik, Katarzyna E.; Nelli, Kyle C.; Kastengren, Alan L.; Fezzaa, Kamel; Powell, Christopher F.; Som, Sibendu; Pei, Yuanjiang; Tzanetakis, Tom; Zhang, Yu; Traver, Michael; Cleary, David

doi:10.4271/2018-01-0303

Cited by 36 publications

(30 citation statements)

References 33 publications

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“…The Cummins injector geometry used for the simulations presented in this work was obtained through x-ray nozzle tomography experiments that were performed at the 7-BM beamline of the Advanced Photon Source (APS) at Argonne National Laboratory [13]. Further details on the experimental setup are reported in the authors' previous work [9]. The geometry obtained through the x-ray tomography experiments has been presented in [9] where a detailed description of the geometry preparation and characterization was provided.…”

Section: Methodsmentioning

confidence: 99%

“…In addition to the fuel property effect, needle lateral motion is also responsible for strong perturbations of the flow field. Previous work [5][6][7][8][9] has shown that the lateral motion of the needle is connected to the fuel tendency to travel along preferential paths inside the nozzle resulting in orifice-to-orifice variability. Furthermore, such variability is enhanced by the presence of in-nozzle cavitation [5,8], especially for those cases in which the amount of fuel vapor is not homogeneously distributed among the orifices due to the influence of the needle radial motion.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, such variability is enhanced by the presence of in-nozzle cavitation [5,8], especially for those cases in which the amount of fuel vapor is not homogeneously distributed among the orifices due to the influence of the needle radial motion. Experiments performed by the authors have shown that the needle radial motion can be affected by considerable shot-to-shot variability [9]. As a consequence, the lateral oscillations could likely cause the location of such flow-field and cavitation non-uniformities to change for each injection events (i.e., engine cycle) possibly resulting in cycle-to-cycle variability (CCV).…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, the lateral oscillations could likely cause the location of such flow-field and cavitation non-uniformities to change for each injection events (i.e., engine cycle) possibly resulting in cycle-to-cycle variability (CCV). The authors have shown that in simulations, and for a non-cavitating fuel such as diesel, orifice-to-orifice differences as high as 10% could be found for separate injection events [9]. This might become an even more critical issue for heavyduty GCI applications in which swirl and tumble motions are generally less intense than for light-duty engines and therefore promote lower air-fuel mixing.…”

Section: Introductionmentioning

confidence: 99%

“…All the results obtained with SRG are compared against diesel results. The novelty of this work is in the simulation of a production eight-hole heavy-duty diesel injector whose geometry and needle motion were measured with well-established, validated x-ray techniques [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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In-Nozzle Cavitation-Induced Orifice-to-Orifice Variations Using Real Injector Geometry and Gasoline-Like Fuels

Torelli¹,

Matusik²,

Sforzo³

et al. 2018

Proceedings of the 10th International Symposium on Cavitation (CAV2018)

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Many concurrent sources contribute to cycle-to-cycle variability (CCV) in internal combustion engines. This variability is undesirable, as it is responsible for deviations from the expected operating conditions, which in turn affect the engine efficiency and performance. Shot-to-shot variability connected to the fuel injection process is one strong candidate among CCV's many sources. Previous numerical work employing diesel fuel in a nozzle geometry measured with x-ray diagnostics has shown that manufacturing tolerances and needle radial motion are responsible for orifice-to-orifice variations in total injected mass. These variations are significant in the presence of shot-to-shot variability in the needle radial motion. The growing interest for low temperature combustion modes such as gasoline compression ignition has made the use of gasoline-like fuels in compression ignited engines desirable. However, when operating under typical diesel conditions, these fuels generally show considerable propensity for cavitation in the orifices and at the needle seat, due to their high volatility. In previous work, in-nozzle cavitation has been shown to correlate strongly with needle radial motion. This might constitute another source of CCV, as cavitation within the orifices might enhance the already present shot-to-shot variability by reducing the available cross-sectional areas and the relative orifice discharge coefficients. In addition, the systematic presence of cavitation might also result in the local erosion of the nozzle internal geometry, leading to even higher variability with time. This study focuses on the evaluation of orifice-to-orifice variability of gasoline-like fuel injection under diesel operating conditions. High-resolution x-ray geometry characterization of an eight-hole heavy-duty diesel injector has been combined with new measurements of the needle motion using a straight-run gasoline. A wellvalidated computational setup using the CONVERGE code was employed to perform a series of simulations, which highlighted the influence of cavitation on the internal nozzle flow. This combined effect of cavitation, needle radial motion, and orifice-to-orifice differences found is expected to have a strong influence on shot-to-shot variations.

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Section: Methodsmentioning

confidence: 99%