This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Experimental Analysis of Transient Flow Phenomena in Multi-Jet Common-Rail Systems
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 11, 2005 by Consiglio Nazionale delle Ricerche in Italy
Annotation ability available
A detailed experimental analysis of the pressure wave propagation phenomena and fuel-injection system dynamics in a last-generation C.R Multijet system was carried out on a high performance new test bench Moehwald-Bosch MEP2000-CA4000 under real engine simulated conditions. Specific attention was paid to the wave propagation induced pressure oscillations as well as to their relationships with system control parameters and multiple-injection performance. In particular the authors aim at illustrating how the geometrical features of each component of the injection-system hydraulic layout influence the aforementioned wave motion providing a key for design optimization in order to obtain efficient multiple injection performance.
A parametric analysis on the whole injection system performance when multiple injections are executed in an injection cycle has been carried out, taking the most important geometric features, i.e. pipe lengths, pipe diameters, and rail volume, as test parameters. A simple zero-dimensional model has been developed to work out the natural frequencies of the injection system when hydraulic layout is modified. Such a model was shown to be capable of correctly predicting the main frequencies of the hydraulic circuit and their dependence on the geometrical parameters. The good agreement between the outcome of this simple model and the experimental data also substantiated the reliable authors’ interpretation of the cause and effect main relations underlying the complex flow phenomena occurring in the system. The hydraulic circuit frequencies are compared to the natural frequencies of the mobile elements present in the electro-injector to individuate mechanical resonance conditions. Furthermore the energizing times, which produce hydraulic resonance, i.e. high-amplitude pressure oscillations, are determined: these solenoid excitation durations represent critical values to be employed when multiple injections are performed.
A concrete layout solution to minimize the problem of fluid dynamics interaction between injectors, that is disturbances produced by one injector on the others, is provided and justified. Finally a study about the possibility of severely reducing the rail volume has been leaded in order to obtain a system with a more prompt dynamic response during engine speed transients and with condensed overall dimensions.
CitationCatania, A., Ferrari, A., Manno, M., and Spessa, E., "Experimental Analysis of Transient Flow Phenomena in Multi-Jet Common-Rail Systems," SAE Technical Paper 2005-24-048, 2005, https://doi.org/10.4271/2005-24-048.
- Stumpp, G. Ricco, M. 1996 “Common Rail – An Attractive Fuel Injection System for Passenger Car DI Diesel Engines” SAE Paper 960870
- Boehner, W. Hummel, K. 1997 “Common Rail Injection System of Commercial Diesel Vehicles” SAE Paper 970345
- Benajes, J. Molina, S. Garcia, J.M. 2001 “Influence of Pre and Post Injection on the Performance and Pollutant Emissions in a HD Diesel Engine” SAE Paper 2001-01-0526
- Payri, F. Benajes, J. Pastor, J.V. Molina, S. 2002 “Influence of the Post-Injection Pattern on Performance, Soot and NO x Emissions in a HD Diesel Engine” SAE Paper 2002-01-0502
- Chryssakis, C. A. Assanis, D.N. Kook, S. Bae, C. 2005 “Effect of Multiple Injections on Fuel-Air Mixing and Soot Formation in Diesel Combustion Using Direct Flame Visualization and CFD Techniques” Proceedings, Spring Technical Conference of the ASME ICE, ICES 2005-1016 Chicago, IL April 5–7
- Catania, A. E. Ferrari, A. Manno, M. Spessa, E. 2005 “Experimental Investigation of Dynamic Effects on Multiple-Injection Common Rail System Performance” Proceedings, Spring Technical Conference of the ASME ICE, ICES 2005-1108 Chicago, IL April 5–7
- Catania, A. E. Ferrari, A. Manno, M. 2005 “Development and Application of a Complete Common Rail Injection System Mathematical Model for Layout Hydrodynamic Analysis” Proceedings, Spring Technical Conference of the ASME ICE , ICES 2005-1018 Chicago, IL April 5–7
- Bosch, W. 1966 “The Fuel Rate Indicator: a New Measuring Instrument for Display of the Characteristics of Individual Injection” SAE Paper 660749
- Catania, A. E. Ferrari, A. Manno, M. Pellettieri, R. Spessa, E. 2004 “Sviluppo, messa a punto e strumentazione di un banco prova ad alte prestazioni per sistemi di iniezione diesel: primi risultati sperimentali sulla dinamica di sistemi Common Rail” Atti del 59° Congresso ATI 2 821 834
- Catalano, L. A. Tondolo, V. A. Dadone, A. 2002 “Dynamic Rise of Pressure in the Common-Rail Fuel Injection System” SAE Paper 2002-01-0210