CFD Analysis of Port Water Injection in a GDI Engine under Incipient Knock Conditions

Jacopo Zembi, Michele Battistoni, Francesco Ranuzzi, Nicolò Cavina and Matteo De Cesare
Additional contact information
Jacopo Zembi: Department of Engineering, University of Perugia, 06125 Perugia, Italy
Michele Battistoni: Department of Engineering, University of Perugia, 06125 Perugia, Italy
Francesco Ranuzzi: Department of Industrial Engineering, University of Bologna, 40136 Bologna, Italy
Nicolò Cavina: Department of Industrial Engineering, University of Bologna, 40136 Bologna, Italy
Matteo De Cesare: Magneti Marelli Powertrain, 40131 Bologna, Italy

Energies, 2019, vol. 12, issue 18, 1-22

Abstract: This paper investigates, through computational fluid dynamics (CFD) simulations, the knock resistance improvements that can be obtained in a turbo-charged GDI engine with water injection. In a first step, water and gasoline injector models are validated comparing the results with experimental data from constant volume chamber tests. Then, multi-cycle simulations are performed using the G-equation turbulent combustion model focusing on spray evolution and wall film dynamics. The main intent is analyzing the effectiveness of different water injection timings and injection pressures in a port water injection (PWI) installation. Combustion rates are validated against experimental engine data, with and without water injection. Afterwards, in order to predict autoignition behavior with different spark advance (SA) timings, the extended coherent flamelet model (ECFM) combined with a tabulated kinetic ignition (TKI) dataset is used. End-gas autoignition delays are calculated using a reduced mechanism for toluene primary reference fuel (TPRF), which revealed essential for capturing actual gasoline ignition characteristics. Results indicate that the water atomization quality, i.e., injection pressure, is significant in a PWI installation allowing a reduction of the water wall film formation in the ports. Water injection timing needs also to be carefully chosen for optimized performance. As the injected water allows the SA to be increased, the overall benefits on indicated mean effective pressure and fuel consumption are quantified under the same knock safety margin, matching adequately well the available measurements.

Keywords: port water injection; knock; knock-limited spark advance; turbo-charged GDI engine; CFD simulation; tabulated kinetic ignition (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
https://www.mdpi.com/1996-1073/12/18/3409/pdf (application/pdf)
https://www.mdpi.com/1996-1073/12/18/3409/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:12:y:2019:i:18:p:3409-:d:263961

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().