gdi basics seminar
TRANSCRIPT
ANALYSIS OF AIR-FUEL FLOW
IN GASOLINE DIRECT INJECTION ENGINE
PROJECT GUIDE - Dr. J G SURYAWANSHISTUDENTS - NIKHIL MOORJANI
SHREYAS SHARMAESHANA RANAWAKA
Aim of the Project
Study the Technology behind Gasoline Direct Injection engine
Comparison of GDI engine with Carburetor and Multipoint Injection engines
To develop CFD fluid flow model inside a GDI engine using Fluent and Gambit Software.
Project Planning
Studying the Concept of GDI from various research papers and other study materials with the help of our Project guide.
Learning the CFD flow analysis software (FLUENT) and Solid modeling Software (GAMBIT).
Creating the necessary model and meshing it accordingly.
Carrying out the calculations of the flow and generating the graphical images of the simulation.
Comparing the results we obtained with the data already available in research papers and other sources.
Progress of the Project till now.
Studying the Theory and concept behind GDI Engine
Why GDI engines over Carburetor and MPFI engines?
Carburetor is a chamber where petrol and air was mixed in a fixed ratio and then sent to cylinders to burn it to produce power.
MPFI emerged an Intelligent way to do what the Carburetor does. In MPFI system, each cylinder has one injector (which makes it multi-point). Each of these Injectors are controlled by one central car computer.
Gasoline Direct Injection Engine The fuel is injected under high pressure directly into the combustion
chamber, just before ignition by the spark plug, this allows the precise control of charge stratification vital to ignite ultra-lean air / fuel mixtures.
Unlike conventional engines, GDI uses upright straight intake port, accompany with a concave-section piston surface, swirl air flow will be generated during compression stroke.
Fuel Injection takes place in two stages. One during the Suction stroke and second one just before the ignition
MERITS AND DEMERITS OF GDI ENGINE
oHigh Volumetric efficiency
oLower fuel consumption
oMore power output (Higher compression ratio 12.5 : 1)
oLower octane requirement
oMore rapid starting
oReduced CO2 emissions
oLower Octane requirement
oMore precise air-fuel ratio control
oImproved transient response
oOne of the few drawbacks of GDI engine is the higher NOX pollutant level.
oAutomobiles which uses GDI engines already Hyundai (Gamma, Lambda, Theta i & ii engines) Renault IDE Mitsubishi (Montero engine) General Motors
oMax Power Out put 180hp at 6700rpm (GM 2.4L 4 cyl inline with 11.4:1 compression ratio) 255hp at 214 lb-ft of torque (Chevrolet 3L V6 ) 200hp 2L VW
oFuel Consumption Expected 10.6km/l in 2.4l Engine.
Few details on GDI Engines which are already in use
Performance comparison between MPI and GDI engine
CFD Modeling of the Flow
o Software used Fluent (By ANSYS) GAMBIT
Cylinder specification used in the modeling
Bore x Stroke 88 x 97Compression Ratio 10.5 , 12
Displacement 2.4L (4 Cylinder)
Injector Piezo-actuated outwardly-opening type
Piston Curved top
Actuation Piezo
Type Outward-Opening
Nominal Spray Cone Angle 900
Static Flow Rate More than 35 g/s
Fuel Pressure Range 100-200 bar
CFD Modeling Procedure
oDrawing the Cylinder and Other engine components Using Gambit
oMeshing the Combustion cylinder using GAMBIT
oImporting the Geometry to ANSYS Fluent
oDefining the necessary boundary conditions for the combustion cylinder
oSolving the flow using Fluent1. Solving the flow equations for air and fuel flow 2. Solving the energy equation for combustion and heat transfer
o Generation of Graphical images and graphs for the simulation
Example Flow Model of a MPFI Engine for learning purpose
Example Flow Model of a MPFI Engine for learning purpose
Example Flow Model of a MPFI Engine for learning purpose
The meshing of the 2D Engine Geometry
3D Cylinder development in GAMBIT
The End
References-
oSAE technical paper series
oWiki-Pedia (www.wikipedia.org)
oHyundai Motors Website