Physical and chemical effects of low octane gasoline fuels on compression ignition combustion. (1st December 2016)

• Record Type: Journal Article
• Authors: Badra, Jihad; Viollet, Yoann; Elwardany, Ahmed; Im, Hong G.; Chang, Junseok
• Is Part Of: Applied energy. Volume 183(2016)
• Page Start: 1197
• Page End: 1208
• Publication Date: 2016-12-01
• Subjects: Naphtha fuels -- Low-octane fuel -- Gasoline compression ignition engine -- Mixing -- Ignition delay times; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2016.09.060
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: New experimental data SOI sweep in GCI engine running on naphtha fuels. Despite the differences in the fuel's properties, the combustion and emissions were similar. CFD engine simulations successfully reproduced the experimental trends. The chemical and physical effects were isolated numerically and detailed analysis was performed. Abstract: Gasoline compression ignition (GCI) engines running on low octane gasoline fuels are considered an attractive alternative to traditional spark ignition engines. In this study, three fuels with different chemical and physical characteristics have been investigated in single cylinder engine running in GCI combustion mode at part-load conditions both experimentally and numerically. The studied fuels are: Saudi Aramco light naphtha (SALN) (Research octane number (RON) = 62 and final boiling point (FBP) = 91 °C), Haltermann straight run naphtha (HSRN) (RON = 60 and FBP = 140 °C) and a primary reference fuel (PRF65) (RON = 65 and FBP = 99 °C). Injection sweeps, where the start of injection (SOI) is changed between −60 and −11 CAD aTDC, have been performed for the three fuels. Full cycle computational fluid dynamics (CFD) simulations were executed using PRFs as chemical surrogates for the naphtha fuels. Physical surrogates based on the evaporation characteristics of the naphtha streams have been developed and their properties have been implemented in the engine simulations. It was found that the three fuels have similar combustion phasings and emissions at the conditions tested in this work with minor differences at SOI earlier than −30 CAD aTDC. These trends were successfully reproduced by the CFD calculations. The chemical and physical effects were further investigated numerically. It was found that the physical characteristics of the fuel significantly affect the combustion for injections earlier than −30 CAD aTDC because of the low evaporation rates of the fuel because of the higher boiling temperature of the fuel and the colder in-cylinder air during injection.