Application of Optical Techniques to the Study of Mixture Preparation in Direct Injection Gasoline Engines and Validation of a CFD Model

2000 ◽  
Author(s):  
Martin Gold ◽  
Gang Li ◽  
Steve Sapsford ◽  
John Stokes
Keyword(s):  
Direct Injection ◽  
Cfd Model ◽  
Optical Techniques ◽  
Gasoline Engines ◽  
Mixture Preparation

Simulation of cavitation in outward-opening piezo-type pintle injector nozzles

2008 ◽  
Vol 222 (10) ◽  
pp. 1895-1910 ◽  
Author(s):  
E Giannadakis ◽  
D Papoulias ◽  
A Theodorakakos ◽  
M Gavaises
Keyword(s):  
Bubble Growth ◽  
Large Scale ◽  
Direct Injection ◽  
Bubble Formation ◽  
Needle Valve ◽  
Transient Effects ◽  
Cavitation Model ◽  
Gasoline Engines ◽  
Opening And Closing ◽  
Vapour Film

The onset and development of cavitation in the annular needle seat passage of piezo-driven outward-opening pintle injector nozzles used with spray-guided direct-injection gasoline engines are studied using a Eulerian-Lagrangian computational fluid dynamics cavitation model. Cavitation is formed because of the fluid acceleration taking place at the needle sealing area and it has been found to be affected by its geometric details. Various submodels for nucleation and bubble formation, further bubble growth and collapse, as well as bubble break-up and transport are incorporated into the model. Qualitative model validation is performed against experimental data reported elsewhere in large-scale nozzle replicas, showing similar cavitation patterns to be formed. These consist of vapour pockets rather than a continuous vapour film and develop transiently in a rather chaotic manner around the circumferential needle sealing area, even under stationary geometry and fixed-flowrate conditions. Further transient effects associated with the fast opening and closing of the piezo-controlled needle valve are also presented.

Cavitation in Fuel Injection Systems for Spray-Guided Direct Injection Gasoline Engines

2007 ◽  
Author(s):  
D. Papoulias ◽  
E. Giannadakis ◽  
N. Mitroglou ◽  
M. Gavaises ◽  
A. Theodorakakos
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Gasoline Engines

scholarly journals LES study on mixing and combustion in a Direct Injection Spark Ignition engine

2018 ◽  
Vol 73 ◽  
pp. 32
Author(s):  
Nicolas Iafrate ◽  
Anthony Robert ◽  
Jean-Baptiste Michel ◽  
Olivier Colin ◽  
Benedicte Cuenot ◽  
...  
Keyword(s):  
Ignition Time ◽  
Direct Injection ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Pollutant Emissions ◽  
Spark Ignition Engines ◽  
Eddy Simulation ◽  
Mixture Preparation ◽  
The Impact

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.

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