A parametric study for enabling reactivity controlled compression ignition (RCCI) operation in diesel engines at various engine loads. (1st August 2016)

• Record Type: Journal Article
• Authors: Wang, Yifeng; Yao, Mingfa; Li, Tie; Zhang, Weijing; Zheng, Zunqing
• Is Part Of: Applied energy. Volume 175(2016)
• Page Start: 389
• Page End: 402
• Publication Date: 2016-08-01
• Subjects: Reactivity controlled compression ignition (RCCI) -- Operating range expansion -- Parametric study -- Load-limiting factors -- Diesel engine; RCCI reactivity controlled compression ignition -- LTC low temperature combustion -- EGR exhaust gas recirculation -- PCCI premixed charge compression ignition -- BMEP brake mean effective pressure -- CN cetane number -- IMEP indicated mean effective pressure -- SOC start of combustion -- SOI start of injection -- CA crank angle -- CA90 crank angle where 90% of the total heat release occurs -- ATDC after top dead center -- CA50 crank angle where 50% of the total heat release occurs -- HCCI homogeneous charge compression ignition -- CA crank angle -- NOx nitrogen oxides -- CO carbon monoxide -- UHC unburned hydrocarbon -- MPRR maximum pressure rise rate -- ISFC indicated specific fuel consumption -- COVIMEP the coefficient of variation of the indicated mean effective pressure; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2016.04.095
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: The effect of operational parameters on RCCI combustion and emissions was studied. Optimal combustion control strategies over the RCCI load region were studied. Key limiting factors for extension of the load limits of RCCI engine are analyzed. Abstract: Reactivity controlled compression ignition (RCCI) is demonstrated as a promising combustion strategy to achieve high efficiency and clean combustion. In this work, an extensive experimental investigations are performed focusing on investigating the effect of operational parameters (intake pressure, exhaust gas recirculation rate, gasoline proportion, diesel injection timing, etc.) on the combustion performance and emission characteristics at various engine loads. Then, the key limiting factors for extension of the upper and lower limits of RCCI operations are analyzed. Results suggest that ultra-low NOx and soot emissions as well as high thermal efficiency can be achieved simultaneously with gasoline/diesel dual-fuel RCCI regime at moderate-to-high loads, while diesel low temperature combustion (LTC) with single-shot fuel injection can be more suitable for low-load operations. Moreover, to extend the RCCI operating range to lower loads, the proportion of diesel injection should be raised to increase the global reactivity of the in-cylinder charge. While increasing EGR rate and gasoline proportion as well as advancing diesel injection timing can lower the global reactivity of the cylinder charge and avoid premature combustion, excessive pressure rise rate and high peak in-cylinder pressure, thereby in favor of extending RCCI operation to higher loads. However, ultra-high EGR rate or too early fuel injection can lead to unstable combustion, making combustion phasing control extremely difficult.