Numerical Study of the Effects of Lambda and Injection Timing on RCCI Combustion Mode

Reactivity Controlled Compression Ignition (RCCI), which is a low temperature combustion mode based on the principle of working with dual fuel, has attracted the attention of researchers in recent years due to its advantages such as high thermal efficiency, low NOx and soot emissions, and controllability of combustion. In this study, the effects of injection timing and lambda on RCCI combustion mode were investigated numerically by validating the experimental data with Converge CFD software. A four-cylinder, four-stroke gasoline direct-injection engine with a compression ratio of 9.2 was used in RCCI combustion mode at an engine speed of 1000 rpm. The maximum cylinder pressure also increased and RCCI combustion was advanced while the injection timing was advanced. The highest peak pressure was obtained at SOI=-50°CA aTDC, and the lowest peak pressure was obtained at SOI=-25°CA aTDC. Similarly, the highest peak HRR value was acquired as 213 J/°CA at SOI=-50°CA aTDC. It has been observed that as the lambda decreases, the maximum cylinder pressure increases, and combustion advances. In addition, the heat release rises with a decrease in lambda value. The maximum heat release rate was acquired as 77.91 J/°CA at λ=1.2. The results show that injection timing and lambda have a great influence on RCCI combustion mode and the combustion phase can be controlled with these parameters.

___

  • [1] Ansari E, Poorghasemi K, Khoshbakht Irdmousa B, Shahbakhti M, Naber J. Efficiency and emissions mapping of a light duty diesel-natural gas engine operating in conventional diesel and RCCI modes. SAE Technical Paper, 2016-01-2309.
  • [2] Poorghasemi K, Saray RK, Ansari E, Irdmousa BK, Shahbakhti M, Naber JD. Effect of diesel injection strategies on natural gas/diesel RCCI combustion characteristics in a light duty diesel engine. Applied Energy, 2017; 199: 430-446.
  • [3] Liu HF, Xu J, Zheng ZQ, Li SJ, Yao MF. Effects of fuel properties on combustion and emissions under both conventional and low temperature combustion mode fueling 2,5-dimethylfuran/diesel blends. Energy, 2013; 62: 215-223.
  • [4] Hanson RM, Kokjohn SL, Splitter DA, Reitz RD. An experimental investigation of fuel reactivity controlled PCCI combustion in a heavy-duty engine. SAE Int. J. Engines, 2010-01-0864.
  • [5] Kakoee A, Bakhshan Y, Aval SM, Gharehghani A. An improvement of a lean burning condition of natural gas/diesel RCCI engine with a pre-chamber by using hydrogen. Energy Convers. Manag., 2018; 166: 489-499.
  • [6] Kakoee A, Bakhshan Y, Gharehghani A, Salahi M. Numerical comparative study of hydrogen addition on combustion and emission characteristics of a natural-gas/dimethyl-ether RCCI engine with pre-chamber. Energy, 2019; 186: 115878.
  • [7] Taghavi M, Gharehghani A, Nejad FB, Mirsalim M. Developing a model to predict the start of combustion in HCCI engine using ANN-GA approach. Energy Convers. Manag., 2019; 195: 57-69.
  • [8] Uyumaz A, Solmaz H. Experimental investigation of the effects of lambda and injection timing on combustion and performance characteristics in a RCCI engine. Gazi University Journal of Science Part C: Design and Technology, 2016; 4(4):299-308.
  • [9] Kokjohn SL, Hanson RM, Splitter DA, Reitz RD. Experiments and modeling of dual-fuel HCCI and PCCI combustion using in-cylinder fuel blending, SAE Technical Paper, 2009-01-2647.
  • [10] Benajes J, Molina S, García A, Belarte E, Vanvolsem M. An investigation on RCCI combustion in a heavy duty diesel engine using in-cylinder blending of diesel and gasoline fuels. Applied Thermal Engineering, 2014; 63: 66-76.
  • [11] Ma S, Zheng Z, Liu H, Zhang Q, Yao M. Experimental investigation of the effects of diesel injection strategy on gasoline/diesel dual-fuel combustion. Applied Energy, 2013; 109: 202-212.
  • [12] Nieman DE, Dempsey AB, Reitz RD. Heavy-duty RCCI opera-tion using natural gas and diesel. SAE Technical Paper, 2012-01-0379.
  • [13] Tong L, Wang H, Zheng Z, Reitz RD, Yao M. Experimental study of RCCI combustion and load extension in a compression ignition engine fueled with gasoline and PODE. Fuel, 2016; 181: 878-886.
  • [14] Uyumaz A, Solmaz H, Boz F, Yilmaz E, Polat S. The effects of lambda on combustion characteristics in a reactive controlled compression ignition engine. Afyon Kocatepe University Journal of Science and Engineering, 2017; 17: 1146-1156.
  • [15] Mohammadian A, Chehrmonavari H, Kakaee A, Paykani A. Effect of injection strategies on a single-fuel RCCI combustion fueled with isobutanol/isobutanol+DTBP blends. Fuel, 2020; 278: 118219.
  • [16] Solmaz H, Ipci D. Control of combustion phase with direct injection timing for different inlet temperatures in an RCCI engine. Journal of Thermal Science and Technology, 2020; 40(2): 267-279.
  • [17] Arora JK. Design of real-time combustion feedback system and experimental study of an RCCI engine for control. PhD Thesis, Michigan Technological University, 2016.
  • [18] Halis S, Nacak C, Solmaz H, Yilmaz E, Yucesu HS. Investigation of the effects of octane number on combustion characteristics and engine performance in a HCCI engine. Journal of Thermal Science and Technology, 2018; 38(2): 99-110.
  • [19] Chang J, Guralp O, Filipi Z, Assanis D, Kuo TW, Najt P, Rask R. New heat transfer correlation for an HCCI engine derived from measurements of instantaneous surface heat flux. SAE Technical Paper, 2004-01-2996.
  • [20] Dukowicz JK, A particle-fluid numerical model for liquid sprays. Journal Computational Physics, 1980; 35: 229-253.
  • [21] Beale JC, Reitz RD. Modeling spray atomization with the Kelvin-Helmholtz/ Rayleigh-Taylor hybrid model. Atomization Sprays, 1999; 9: 623-650.
  • [22] Convergent Science Inc., CONVERGE (v2.3) theory manual, 2016.
  • [23] Bahrami S, Poorghasemi K, Solmaz H, Calam A, Ipci D. Effect of nitrogen and hydrogen addition on performance and emissions in reactivity controlled compression ignition. Fuel, 2021; 292: 120330.
  • [24] Senecal PK, Pomraning E, Richards KJ, Briggs TE, Choi CY, McDavid RM, Patterson MA. Multi-dimensional modeling of direct-injection diesel spray liquid length and flame lift-off length using CFD and parallel detailed chemistry. SAE Technical Paper, 2003-01-1043.
  • [25] Luong MB, Luo Z, Lu TF, Chung SH, Yoo CS. Direct numerical simulations of the ignition of lean primary reference fuel/air mix-tures under HCCI condition. Combustion and Flame, 2013; 160(10): 2038-2047.
  • [26] Nazemi M, Shahbakhti M. Modeling and analysis of fuel injec-tion parameters for combustion and performance of an RCCI en-gine. Applied Energy, 2016; 165: 135-150.
  • [27] Li J, Yang WM, An H, Zhao D. Effects of fuel ratio and injection timing on gasoline/biodiesel fueled RCCI engine: A modeling study. Applied Energy, 2015; 155: 59-67.
  • [28] Curran S, Hanson R, Wagner R. Efficiency and emissions map-ping of RCCI in a light-duty diesel engine. SAE Technical Paper, 2013-01-0289.