Experimental Investigation and Thermodynamic Modelling of an RCCI Engine With Gasoline and Ethanol As Pilot Fuels

2019 ◽  
Author(s):  
Chinmaya Mishra ◽  
P. M. V. Subbarao
Keyword(s):  
Experimental Investigation ◽  
Engine Performance ◽  
High Reactivity ◽  
Low Temperature Combustion ◽  
Oxides Of Nitrogen ◽  
Reactivity Controlled Compression Ignition ◽  
Simultaneous Reduction ◽  
Temperature Combustion ◽  
Energy Share ◽  
Reduction Of Oxides

Abstract Reactivity controlled compression ignition (RCCI) is an emerging premix low temperature combustion philosophy. Contemporary understanding suggests that RCCI concept with a premix high octane (low reactivity) fuel and direct injected high cetane (high reactivity) fuel ensures in-cylinder stratification of equivalence ratio as well as fuel reactivity. This stratification of reactivity coupled with partial premixing ensures simultaneous reduction of oxides of nitrogen and smoke. Furthermore, the induced delay in combustion phasing and high compression ratio ensures diffusive flames away from piston surface resulting in higher thermal efficiency. In the present work, an experimental investigation was carried out using port injected gasoline and anhydrous ethanol as low reactivity pilot fuels and direct injected diesel as high reactivity main fuel under various energy share. A comparative study of both the pilot fuels were carried out in terms of engine performance, emission and in-cylinder behavior in both representative and statistical perspective.

Effect of Fuel Injection Pressure and Premixed Ratio on Mineral Diesel-Methanol Fueled Reactivity Controlled Compression Ignition Mode Combustion Engine

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Nikhil Sharma ◽  
Dev Prakash Satsangi ◽  
Avinash Kumar Agarwal
Keyword(s):  
Fuel Injection ◽  
Combustion Engine ◽  
Engine Performance ◽  
Injection Pressure ◽  
High Reactivity ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Reactivity Controlled Compression Ignition ◽  
Hc Emissions ◽  
Fuel Injection Pressure

Abstract Reactivity controlled compression ignition (RCCI) mode combustion has attracted significant attention because of its superior engine performance and significantly lower emissions of oxides of nitrogen (NOx) and particulate matter (PM) compared with conventional compression ignition (CI) mode combustion engines. In this experimental study, effects of fuel injection pressure (FIP) of high reactivity fuel (HRF) and premixed ratio of low reactivity fuel (LRF) were evaluated on a diesel-methanol fueled RCCI mode combustion engine. Experiments were performed in a single cylinder research engine at a constant engine speed (1500 rpm) and constant engine load (3 bar BMEP) using three different FIPs (500, 750, and 1000 bar) of mineral diesel and four different premixed ratios (rp = 0, 0.25, 0.50, and 0.75) of methanol. Results showed that RCCI mode resulted in more stable combustion compared with baseline CI mode combustion. Increasing FIP resulted in relatively higher knocking, but it reduced with increasing premixed ratio. Relatively higher brake thermal efficiency (BTE) of RCCI mode combustion compared with baseline CI mode combustion is an important finding of this study. BTE increased with increasing FIP of mineral diesel and increasing premixed ratio of methanol. Relatively dominant effect of increasing FIP on BTE at higher premixed ratios of methanol was also an important finding of this study. RCCI mode combustion resulted in higher carbon monoxide (CO) and hydrocarbon (HC) emissions, but lower PM and NOx emissions compared with baseline CI mode combustion. Increasing FIP of HRF at lower premixed ratios reduced the number concentration of particles; however, effect of FIP became less dominant at higher premixed ratios. Relatively higher number emissions of nanoparticles at higher FIPs were observed. Statistical and qualitative correlations exhibited the importance of suitable FIP at different premixed ratios of LRF on emission characteristics of RCCI mode combustion engine.

scholarly journals The Effect of Hydrogen Addition on Low-Temperature Combustion of Light Hydrocarbons and Alcohols

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3808
Author(s):  
Fekadu Mosisa Wako ◽  
Gianmaria Pio ◽  
Ernesto Salzano
Keyword(s):  
Experimental Data ◽  
Burning Velocity ◽  
Engine Performance ◽  
Pollutant Emissions ◽  
Low Temperature Combustion ◽  
Laminar Burning Velocity ◽  
Nox Formation ◽  
Hydrogen Addition ◽  
Temperature Combustion ◽  
Fuel Mixtures

Hydrogen is largely considered as an attractive additive fuel for hydrocarbons and alcohol-fueled engines. Nevertheless, a complete understanding of the interactions between blended fuel mechanisms under oxidative conditions at low initial temperature is still lacking. This study is devoted to the numerical investigation of the laminar burning velocity of hydrogen–hydrocarbon and hydrogen–alcohol fuels under several compositions. Estimations were compared with experimental data reported in the current literature. Additionally, the effects of hydrogen addition on engine performance, NOX, and other pollutant emissions of the mentioned fuels have been thermodynamically analyzed. From the study, it has been observed that the laminar burning velocity of the fuel mixtures increased with increasing hydrogen fractions and the peak value shifted to richer conditions. Besides, hydrogen fraction was found to increase the adiabatic flame temperatures eventually favoring the NOX formation for all fuel blends except the acetylene–hydrogen–air mixture where hydrogen showed a reverse effect. Besides, hydrogen is also found to improve the engine performances and helps to surge thermal efficiency, improve the combustion rate, and lessen other pollutant emissions such as CO, CO2, and unburned hydrocarbons. The model predicted well and in good agreement with the experimental data reported in the recent literature.

Experimental Investigation of Low-Temperature Combustion (LTC) in an Engine Fueled with Dimethyl Ether (DME)

2009 ◽  
Vol 23 (1) ◽  
pp. 170-174 ◽  
Author(s):  
Zhang Junjun ◽  
Qiao Xinqi ◽  
Wang Zhen ◽  
Guan Bin ◽  
Huang Zhen
Keyword(s):  
Experimental Investigation ◽  
Low Temperature ◽  
Dimethyl Ether ◽  
Low Temperature Combustion ◽  
Temperature Combustion

Low Temperature Combustion Using Nitrogen Enrichment to Mitigate NOx From Large Bore Gas-Fueled Engines

2008 ◽  
Author(s):  
Munidhar S. Biruduganti ◽  
Sreenath B. Gupta ◽  
Raj Sekar
Keyword(s):  
Low Temperature ◽  
Power Density ◽  
Nox Reduction ◽  
Engine Performance ◽  
Air Separation ◽  
Nitrogen Enrichment ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Lean Burn ◽  
Temperature Combustion

Low Temperature Combustion (LTC) is identified as one of the pathways to meet the mandatory ultra low NOx emissions levels set by regulatory agencies. This phenomenon can be realized by utilizing various advanced combustion control strategies. The present work discusses nitrogen enrichment using an Air Separation Membrane (ASM) as a better alternative to the mature Exhaust Gas Re-circulation (EGR) technique currently in use. A 70% NOx reduction was realized with a moderate 2% nitrogen enrichment while maintaining power density and simultaneously improving Fuel Conversion Efficiency (FCE). The maximum acceptable Nitrogen Enriched Air (NEA) in a single cylinder spark ignited natural gas engine was investigated in this paper. Any enrichment beyond this level degraded engine performance both in terms of power density and FCE, and unburned hydrocarbon (UHC) emissions. The effect of ignition timing was also studied with and without N2 enrichment. Finally, lean burn versus stoichiometric operation utilizing NEA was compared. Analysis showed that lean burn operation along with NEA is one of the effective pathways for realizing better FCE and lower NOx emissions.

Improving the Efficiency of Low Temperature Combustion Engines Using a Chamfered Ring-Land

2014 ◽  
Author(s):  
Jae Hyung Lim ◽  
Rolf D. Reitz
Keyword(s):  
Combustion Efficiency ◽  
Dual Fuel ◽  
Low Temperature Combustion ◽  
Combustion Engines ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Hcci Combustion ◽  
Unburned Hydrocarbon ◽  
Piston Crown ◽  
Temperature Combustion

In the present study a chamfered piston crown design was used in order to reduce unburned hydrocarbon (UHC) emissions from the ring-pack crevice. Compared to the conventional piston design, the chamfered piston showed 17%∼41% reduction in the crevice-borne UHC emissions in homogeneous charge compression ignition (HCCI) combustion. Through parametric sweeps 6 mm was identified to be a suitable chamfer size and the mechanism of the UHC reduction was revealed. Based on the findings in this study, the chamfered piston design was also tested in dual-fuel reactivity controlled compression ignition (RCCI) combustion. In the tested RCCI case using the chamfered piston the UHC and CO emissions were reduced by 79% and 36%, respectively, achieving 99.5% combustion efficiency. This also improved gross indicated thermal efficiency from 51.1% to 51.8% in a 9 bar IMEP RCCI combustion case.

Improving the Efficiency of Low Temperature Combustion Engines Using a Chamfered Ring-Land

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Jae Hyung Lim ◽  
Rolf D. Reitz
Keyword(s):  
Combustion Efficiency ◽  
Low Temperature Combustion ◽  
Combustion Engines ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Indicated Mean Effective Pressure ◽  
Hcci Combustion ◽  
Unburned Hydrocarbon ◽  
Piston Crown ◽  
Temperature Combustion

In the present study, a chamfered piston crown design was used in order to reduce unburned hydrocarbon (UHC) emissions from the ring-pack crevice. Compared to the conventional piston design, the chamfered piston showed 17–41% reduction in the crevice-borne UHC emissions in homogeneous charge compression ignition (HCCI) combustion. Through parametric sweeps 6 mm was identified to be a suitable chamfer size and the mechanism of the UHC reduction was revealed. Based on the findings in this study, the chamfered piston design was also tested in dual-fuel reactivity controlled compression ignition (RCCI) combustion. In the tested RCCI case using the chamfered piston the UHC and CO emissions were reduced by 79% and 36%, respectively, achieving 99.5% combustion efficiency. This also improved gross indicated thermal efficiency (gITE) from 51.1% to 51.8% in a 9 bar indicated mean effective pressure (IMEP) RCCI combustion case.

scholarly journals Isolating the effects of reactivity stratification in reactivity-controlled compression ignition with iso-octane and n-heptane on a light-duty multi-cylinder engine

2017 ◽  
Vol 19 (9) ◽  
pp. 907-926 ◽  
Author(s):  
Martin L Wissink ◽  
Scott J Curran ◽  
Greg Roberts ◽  
Mark PB Musculus ◽  
Christine Mounaïm-Rousselle
Keyword(s):  
High Efficiency ◽  
Direct Injection ◽  
Combustion Process ◽  
High Reactivity ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Fundamental Understanding ◽  
Primary Reference ◽  
Primary Reference Fuels

Reactivity-controlled compression ignition (RCCI) is a dual-fuel variant of low-temperature combustion that uses in-cylinder fuel stratification to control the rate of reactions occurring during combustion. Using fuels of varying reactivity (autoignition propensity), gradients of reactivity can be established within the charge, allowing for control over combustion phasing and duration for high efficiency while achieving low NOx and soot emissions. In practice, this is typically accomplished by premixing a low-reactivity fuel, such as gasoline, with early port or direct injection, and by direct injecting a high-reactivity fuel, such as diesel, at an intermediate timing before top dead center. Both the relative quantity and the timing of the injection(s) of high-reactivity fuel can be used to tailor the combustion process and thereby the efficiency and emissions under RCCI. While many combinations of high- and low-reactivity fuels have been successfully demonstrated to enable RCCI, there is a lack of fundamental understanding of what properties, chemical or physical, are most important or desirable for extending operation to both lower and higher loads and reducing emissions of unreacted fuel and CO. This is partly due to the fact that important variables such as temperature, equivalence ratio, and reactivity change simultaneously in both a local and a global sense with changes in the injection of the high-reactivity fuel. This study uses primary reference fuels iso-octane and n-heptane, which have similar physical properties but much different autoignition properties, to create both external and in-cylinder fuel blends that allow for the effects of reactivity stratification to be isolated and quantified. This study is part of a collaborative effort with researchers at Sandia National Laboratories who are investigating the same fuels and conditions of interest in an optical engine. This collaboration aims to improve our fundamental understanding of what fuel properties are required to further develop advanced combustion modes.

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