The quest for more efficient, smarter, and environmentally cleaner liquid-fueled spark ignition (SI) reciprocating engines is more alive and intense now than ever before. GDI SI engines have overcome many of the original limitations and are now becoming commonplace. This seminar will provide a comprehensive overview of GDI engines. Mixture preparation and the combustion process, with an emphasis on strategies for both homogenous and stratified charge operation and control, including issues related to the direct injection of gasoline into the combustion chamber, and fuel injection system requirements for optimal spray characteristics will be explored. Emission of pollutants, fuel economy and effects of some key design and operating parameters will also be covered. The seminar concludes with an overview of a select list of production and prototype GDI engines.
- Describe the rationale behind the GDI engine operation
- Analyze the important processes in GDI engines
- Explain liquid atomization, sprays, and injector requirements for successful GDI operation
- Utilize the technology and the logic behind gasoline direct injection
- Estimate and predict effects of key engine design and operating conditions on performance, combustion, and emission in GDI engines
- Communicate effectively with engineers working on fuel injection, combustion and emission aspects of the GDI engine in your firm or with customers
- Effectively contribute to the design of critical components such as combustion chambers, injectors, and emission reduction strategies
- Explain and utilize trade-offs between increasing engine performance and maintaining low emission characteristics
This seminar will be especially valuable for engineers, technical and project managers, researchers, and academicians. Engineers working on the design of components for high efficiency and performance of GDI engines as well as those directly and indirectly involved in mixture preparation and emission reduction of harmful pollutants from these engines will highly benefit from this course. Environmental engineers desiring to expand their understanding of fuel spray formation, combustion and emissions from GDI engines will benefit, as well as, engineers active in the development and application of software for the modeling and design of combustion chambers, fuel spray dynamics, combustion and emission issues.
- Combustion Systems
- Relative position of spark plug and fuel injector
- How to achieve homogeneous and stratified charge -- spray-, wall-, and air-guided combustion systems
- Fuel Injection System
- Fuel injection system requirements
- Fuel injector requirements and classification
- Fuel Spray Characteristics
- Spray atomization requirements
- Sac spray consideration
- After-injection
- Fuel spray penetration and cone angle
- Split injection
- Sprays characteristics of injectors
- Effects of ambient pressure (density) on spray
- Spray characterization (GDI)
- Mixture Formation
- In-cylinder flow characteristics and GDI combustion
- Fuel-air mixing process
- Spray-wall interactions
- Cold start and wall wetting issues
- Combustion Process and Control Strategies
- Engine Operating Modes and Fuel Injection Strategies
- Early-injection, late-injection, stoichiometric operation
- Operating mode transition
- Split Injection Strategy
- Two-stage, split, and post injection
- Combustion characteristics
- Homogeneous-charge and stratified-charge combustion
- Effects of Engine Operating and Design Parameters on GDI Combustion
- Injection and ignition timings
- Spray cone angle
- EGR
- Knock resistance characteristics
- Air-assisted versus single-fluid GDI fuel system
- Injector, Combustion Chamber, and Intake Valve Deposits
- Emissions of Pollutants - Reduction Approaches
- Hydrocarbon, NOx, particulate and noise emissions
- Fuel Economy
- Factors affecting improved fuel economy
- Fuel economy versus emissions compromise
- Select Gasoline Direct-Injection Engines
- Early DISC engine
- Mitsubishi reverse-tumble-based wall-guided
- Concise review of Toyota, Nissan swirl-based (wall-guided), Audi wall-guided, AVL, FEV air-guided, Ford, Honda spray-guided, Isuzu, Mazda swirl-based, wall-guided, Mercedes-Benz spray-guided, Ricardo tumble-based, wall-guided, Volkswagen tumble-based, wall-guided FSI
- GDI Fuel Rail Technology
- Benefits of Turbocharging a GDI engine
Dr. Chehroudi is Chief Scientist and Group Leader at Advanced Technology Consultants. His previous positions include: Principal Scientist at Air Force Research Laboratory (AFRL/ERC), Chief Scientist at Raytheon STX (formerly Hughes Aircraft STX), Professor of Mechanical Engineering, and Research Staff Member at Princeton University. He specializes in fluid mechanics and heat transfer, laser optical diagnostics, internal combustion engine, gas turbine and rocket engines, structure of sprays, gas turbine engines, combustion, fuel injection issues and emission of pollutants. Dr. Chehroudi is an AIAA Associate Fellow, a member of Ta Beta Pi and the recipient of several SAE awards including the Arch T. Colwell Merit Award, the Ralph R. Teetor Award, the SAE Recognition Award and the SAE Forest R. McFarland Award in recognition of his efforts and leadership in contributions to the Continuing Professional Development Seminars. He has taught courses in the areas of internal combustion engines, thermodynamics, thermophysics of gas flows, combustion, and measurement system, and has more than 150 publications and over 200 presentations in conferences, national and international journals. Dr. Chehroudi has a Ph.D from Princeton University.
Savvas Savvakis
PhD Researcher
Aristotle University of Thessaloniki