Numerical Investigation to Fuel Injection Strategy and Thermal Condition Impacts on GCI Combustion at Low and Medium Loads Using CFD West Virginia Univ

Format:

Book

Conference/Event

Author/Creator:

Kim, Jinsu, author.

Contributor:

Li, Hailin

Sun, Harold

Zhang, Yu

Conference Name:

SAE Powertrains, Fuels & Lubricants Digital Summit (2021-09-28 : Live Online, Pennsylvania, United States)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2021

Summary:

This research numerically investigated the combustion and emissions of a light-duty Gasoline Compression Ignition (GCI) engine operating at low load as well as high load operation conditions using a commercial CFD software Converge. The fuel injection strategies and thermal boundary conditions to build partially premixed and locally rich-stoichiometric region in the combustion chamber while maintaining a globally lean mixture were numerically investigated. The effects of fuel injection pressure, number of injection pulse, and quantity of fuel injected in each pulse were examined and optimized under the given design constraints of 180 bar peak cylinder pressure and 10 bar peak pressure rise rate. At low load, the bulk temperature at intake valve closing (IVC) was varied by exhaust gas rebreathing, uncooled EGR and heated intake air with an external heater to achieve the desired thermal condition and residual gas. The results show that high level of dilution up to 48% was required to mitigate the rapid heat release resulting in high pressure rise and excessive nitrogen oxide (NOx) emission at low load. The optimized dilution slowed down the combustion and effectively decreased flame temperature thus NOx emissions. Also, it was shown that NOx and carbon monoxide (CO), hydrocarbon (HC) had a trade-off relationship because high level of residual gas lowered the combustion temperature which hindered the oxidations of HC and CO. The CFD simulation revealed the importance of the spatial distribution of combustible air/fuel mixture in combustion bowl on the emissions of CO, HC and soot. It was concluded that GCI combustion with proper thermal condition was able to achieve 43% gross indicated thermal efficiency with lower NOx, HC and CO than the same size diesel engine at low load condition

Notes:

Vendor supplied data

Publisher Number:

2021-01-1155

Access Restriction:

Restricted for use by site license