Assessment of gasoline direct injector fouling effects on fuel injection, engine performance and emissions. (15th June 2018)

• Record Type: Journal Article
• Authors: Badawy, Tawfik; Attar, Mohammadreza Anbari; Xu, Hongming; Ghafourian, Akbar
• Is Part Of: Applied energy. Volume 220(2018)
• Page Start: 351
• Page End: 374
• Publication Date: 2018-06-15
• Subjects: DISI engine -- Injector fouling -- Mixture preparation -- Combustion -- Emissions; ASOI after start of injection -- ATDC after top dead centre -- BTDC before top dead centre -- CAD crank angle degree -- CNF cumulative number fraction -- COV coefficient of variation -- CVF cumulative volume fraction -- DCA deposit control additives -- ECU engine control unit -- EMOP exhaust maximum opening position -- ETBE ethyl tertiary butyl ether -- IMOP intake maximum opening position -- SLID spatial light intensity distribution -- EDS energy dispersive X-ray spectroscopy -- GDI gasoline direct injection -- HC hydrocarbon -- HRR heat release rate -- IVC intake valve closing -- IVO intake vale opening -- MFB mass fraction burned -- PDPA phase doppler particle analyser -- PFI port fuel injection -- PLIF planar laser induced fluorescence -- PM, particulate matter -- PN, particulate matter number -- ROI region of interest -- SEM scanning electron microscopy -- SOC start of combustion -- SOI start of injection -- TDC top dead centre -- SMD sauter mean diameter -- ULG unleaded gasoline -- WOT wide open throttle -- IMEP indicated mean effective pressure; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2018.03.032
• Languages: English
• ISSNs: 0306-2619

Abstract

Graphical abstract: Highlights: Effects of injector tip deposits on spray dynamics and atomization were studied. Effects of injector tip deposits on charge inhomogeneity were investigated. Effects of the injector tip deposit on engine performance and emissions were investigated. Abstract: The current optical and thermal experimental tests were mainly focused on obtaining a comprehensive understanding of the effects of gasoline direct injector fouling on mass flow rates, spray characteristics, engine emissions and engine performance. A robust injector fouling cycle was employed to produce coked injectors in a multi-cylinder thermal engine. Deposit build-up in the coked injectors and fouling cycle repeatability was first examined by measurements of fuel flow rate. Macroscopic spray characteristics of the clean and the coked injectors were carried out using high-speed imaging and Planar Laser Induced Fluorescence (PLIF) of sprays foot-print. Fuel droplets size and velocity were characterised with a two-dimensional Phase Doppler Particle Analyser (PDPA). It was observed that the deposit build-up inside injector nozzles and on injector tips reduced the plume cone angle while increased plume penetration length, plume separation angles, mean droplet velocity and size for the coked injector. Impact of injector fouling was further investigated by PLIF measurements of in-cylinder charge inhomogeneity and repeatability in mixture preparation. The coked injectors showed higher degree of inhomogeneity and poorer repeatability in mixture preparation. These were in agreement with combustion analysis results where the coked injectors showed lower load and lower combustion stability compared with the clean injector under same operating conditions. Significantly higher unburned hydrocarbon emissions and particulate number concentration were also observed for the coked injectors. This work was carried out to obtain a broad picture of injector cooking effects in GDI engines.