Effect of Post Injections on In-Cylinder and Exhaust Soot for Low-Temperature Combustion in a Heavy-Duty Diesel Engine

2010 ◽  
Vol 3 (1) ◽  
pp. 496-516 ◽  
Author(s):  
Mohan Bobba ◽  
Mark Musculus ◽  
Wiley Neel
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Low Temperature Combustion ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Temperature Combustion ◽  
Heavy Duty Diesel

scholarly journals Optical Diagnostics of a Late Injection Low-Temperature Combustion in a Heavy Duty Diesel Engine

2007 ◽  
Author(s):  
Thierry Lachaux ◽  
Mark P. B. Musculus ◽  
Satbir Singh ◽  
Rolf D. Reitz
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Liquid Fuel ◽  
Premixed Combustion ◽  
Low Temperature Combustion ◽  
Heavy Duty ◽  
Cool Flame ◽  
Heavy Duty Diesel Engine ◽  
Temperature Combustion ◽  
Heavy Duty Diesel

A late injection, high exhaust-gas recirculation (EGR)-rate, low-temperature combustion strategy was investigated in a heavy-duty diesel engine using a suite of optical diagnostics: chemiluminescence for visualization of ignition and combustion, laser Mie scattering for liquid fuel imaging, planar laser-induced fluorescence (PLIF) for both OH and vapor-fuel imaging, and laser-induced incandescence (LII) for soot imaging. Fuel is injected at top dead center when the in-cylinder gases are hot and dense. Consequently, the maximum liquid fuel penetration is 27 mm, which is short enough to avoid wall impingement. The cool flame starts 4.5 crank angle degrees (CAD) after the start of injection (ASI), midway between the injector and bowl-rim, and likely helps fuel to vaporize. Within a few CAD, the cool-flame combustion reaches the bowl-rim. A large premixed combustion occurs near 9 CAD ASI, close to the bowl rim. Soot is visible shortly afterwards along the walls, typically between two adjacent jets at the head vortex location. OH PLIF indicates that premixed combustion first occurs within the jet and then spreads along the bowl rim in a thin layer, surrounding soot pockets at the start of the mixing-controlled combustion phase near 17 CAD ASI. During the mixing-controlled phase, soot is not fully oxidized and is still present near the bowl-rim late in the cycle. At the end of combustion near 27 CAD ASI, averaged PLIF images indicate two separate zones. OH PLIF appears near the bowl rim, while broadband PLIF persists late in the cycle near the injector. The most likely source of broadband PLIF is unburned fuel, which indicates that the near-injector region is a potential source of unburned hydrocarbons.

scholarly journals Optical Diagnostics of Late-Injection Low-Temperature Combustion in a Heavy-Duty Diesel Engine

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Thierry Lachaux ◽  
Mark P. B. Musculus ◽  
Satbir Singh ◽  
Rolf D. Reitz
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Liquid Fuel ◽  
Premixed Combustion ◽  
Low Temperature Combustion ◽  
Heavy Duty ◽  
Cool Flame ◽  
Heavy Duty Diesel Engine ◽  
Temperature Combustion ◽  
Heavy Duty Diesel

A late-injection, high exhaust-gas recirculation rate, low-temperature combustion strategy is investigated in a heavy-duty diesel engine using a suite of optical diagnostics: chemiluminescence for visualization of ignition and combustion, laser Mie scattering for liquid-fuel imaging, planar laser-induced fluorescence (PLIF) for both OH and vapor-fuel imagings, and laser-induced incandescence for soot imaging. Fuel is injected at top dead center when the in-cylinder gases are hot and dense. Consequently, the maximum liquid-fuel penetration is 27 mm, which is short enough to avoid wall impingement. The cool flame starts 4.5 crank angle degrees (CAD) after the start of injection (ASI), midway between the injector and bowl rim, and likely helps fuel to vaporize. Within a few CAD, the cool-flame combustion reaches the bowl rim. A large premixed combustion occurs near 9 CAD ASI, close to the bowl rim. Soot is visible shortly afterward, along the walls, typically between two adjacent jets. OH PLIF indicates that premixed combustion first occurs within the jet and then spreads along the bowl rim in a thin layer, surrounding soot pockets at the start of the mixing-controlled combustion phase near 17 CAD ASI. During the mixing-controlled phase, soot is not fully oxidized and is still present near the bowl rim late in the cycle. At the end of combustion near 27 CAD ASI, averaged PLIF images indicate two separate zones. OH PLIF appears near the bowl rim, while broadband PLIF persists late in the cycle near the injector. The most likely source of broadband PLIF is unburned fuel, which indicates that the near-injector region is a potential source of unburned hydrocarbons.

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