Effect of injection strategy optimization on PCCI combustion and emissions under engine speed extension in a heavy-duty diesel engine. (15th January 2023)

• Record Type: Journal Article
• Authors: Lu, Yingying; Fan, Chao; Chen, Yufeng; Liu, Yize; Pei, Yiqiang
• Is Part Of: Fuel. Volume 332(2023)Part 1
• Publication Date: 2023-01-15
• Subjects: Heavy-duty diesel engine -- Speed extension -- Injection strategy -- PCCI combustion -- Emissions -- Indicated thermal efficiency; AMR the Adaptive Mesh Refinement -- ATDC after top dead center -- B20 20%GGME + 80%diesel -- B25 butanol concentration of 25% -- CA crank angle -- CO carbon monoxide -- D the duration of main injection -- D1 the duration of pilot injection 1 -- D2 the duration of pilot injection 2 -- E25 ethanol concentration of 25% -- EGR exhaust gas recirculation -- F25 fusel oil concentration of 25% -- F30 fusel oil concentration of 30% -- FIP fuel injection pressure -- GGME garcinia gummi-gutta methyl ester -- M the injection timing of main injection -- M25 methanol concentration of 25% -- MEGSE Mono ethylene glycol supported emulsion -- MSOI the injection timing of main -- MWCNTs multi-walled carbon nanotube -- N25 naphtha concentration of 25% -- NOx nitrogen oxides -- HCCI homogeneous charge compression ignition -- IP25 isopropanol concentration of 25% -- ITEg the gross indicated thermal efficiency -- P1 the injection timing of pilot injection 1 -- P1SOI the injection timing of pilot injection -- P2 the injection timing of pilot injection 2 -- P2SOI injection timing of pilot injection 2 -- PCCI premixed charge compression ignition -- PM particulate matter -- PIP pilot injection proportion -- RCCI reactivity controlled compression ignition -- ROHR rate of heat release -- RSM response surface method -- SOI start of injection -- TDC top dead center -- UHC unburned hydrocarbon; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.126053
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Proper injection strategy should fully utilize the chamber shape to enhance mixing. Retarding single injection timing can increase the indicated thermal efficiency. Two injection strategy can increase fuel-oxygen mixing time and enhance premixing. Optimized injection strategy can decrease NOx and soot and increase the ITEg . Multiple injection strategy prolongs the duration of in-cylinder turbulent motion. At high speed, multiple injections help decrease soot and increase the ITEg . Abstract: To mitigate the consequent emissions of greenhouse gases and to conform to increasingly strict vehicle emission requirements, experiments and numerical simulation were used to study effects of multiple injection strategy on premixed charge compression ignition (PCCI) combustion and emissions under speed extension in a heavy-duty diesel engine fueled with diesel. As the speed increases, the injection duration is prolonged, the injection rate is decreased, the fuel-oxygen mixing degree is decreased. In order to enhance fuel-oxygen mixing, the injection timing of single injection should firstly be optimized to fully utilize the shape of the chamber. Compared with single injection, the double injections can increase the mixing time, the optimized multiple injections can further increase the mixing time, making the premixing more sufficient and the combustion more complete. Compared with double injections, the optimized multiple injection strategy used in this paper adds a short pulse pilot injection before the main injection, which prolongs the duration of turbulent motion in the cylinder, and enhances the mixing rate of the main injection fuel and air. Results reveals that for single injection with injection timing of −15°CA ATDC, at low speed, through optimizing the injection strategy, the NOx and soot emissions are reduced by 38.5% and one order of magnitude, respectively, and the gross indicated thermal efficiency (ITEg ) is increased by 8.66%; at medium speed, by optimizing the injection strategy, the NOx and soot emissions are reduced by 59.3% and 70.4%, respectively, and the ITEg is increased slightly by 0.33%; at high speed, by optimizing the injection strategy, the soot emission is decreased significantly, the NOx emissions and the ITEg are increased slightly. It was found that with the increase of speed, the effect of multiple injection strategy on the ITEg and emissions is gradually increased, and the optimization effect of multiple injection strategy is more obvious than that of low speed.