Controlled auto-ignition characteristics of methane–air mixture in a rapid intake compression and expansion machine

Cho, Gyubaek; Jeong, Dong Seop; Moon, Gun-Feel; Bae, Choongsik

doi:10.1016/j.energy.2010.07.002

Cited by 14 publications

(8 citation statements)

References 24 publications

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“…CAI combustion is governed by auto ignition instead of by spark ignition and subsequent flame front propagation [28]. Thanks to its characteristics, CAI engines attracted some attention in the literature [29][30][31][32]. The combustion is characterized by the absence of a flame front propagation and by an extremely rapid evolution.…”

Section: Introductionmentioning

confidence: 99%

“…The combustion is characterized by the absence of a flame front propagation and by an extremely rapid evolution. This allows an efficiency improvement, limited however by the constraint that cylinder pressure rise rate cannot exceed some limits in order to prevent unacceptable mechanical and thermal loads [29]. Biogases were also used to fuel CAI engines and the influence of the amount of recycled combustion products on combustion timing and angular duration was investigated [30]; Jamsaran et al [33] investigated the auto-ignition reactivity of natural gas with regard to the effects of intake air temperature and equivalence ratio; Nishi et al [34] studied the effects of EGR ratio and engine speed on HCCI combustion; Ibrahim et al [35] improved the performance and extended the load range of hydrogen fuelled homogeneous charge compression ignition (HCCI) engine through charge temperature control and CO2 dilution.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

EGR Strategy for NOx Emission Reduction in a CAI Engine Fuelled with Innovative Biogas

Mariani¹,

Unich²,

Minale³

2019

IJES

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Gaseous fuel utilization reduces pollutant emissions and makes thermal energetic systems less dependent on oil. Their carbon content is low, which means low CO2 emissions, and a lower cost with respect to conventional fuels. If gaseous fuels have a non-fossil origin, their adoption would have a beneficial impact on global CO2 balance and on the dependence of the energy sector from fossil fuels. Biogas is produced from the anaerobic digestion of organic materials, with the composition depending on the feedstock and on the production processes. The use of biogas in internal combustion engines (ICE) is very attractive. However, the presence in the biogas of an inert gas like CO2 has adverse effects on combustion, reducing combustion speed, narrowing flammability limits with harmful effects on combustion stability. A possible way for improving combustion performance of biogas is hydrogen addition. Innovative anaerobic digestion processes, which maximize the H2 yield, can end up with biogases made of CH4, CO2 and H2. The biogas, generally adopted as fuel in positive ignition ICEs, is also suitable for Controlled Auto Ignition (CAI) engines. Aim of this work is to investigate the biogas combustion in CAI ICE by means of numerical simulations. The effect of fuel composition and EGR on engine performance and exhaust emissions was evaluated. Authors compared conventional and innovative biogases composed by CH4, CO2 and H2 of different compositions. CAI systems are controlled with varying intake gas conditions: air-fuel ratio, boost pressure and charge temperature. The temperature depends on recycled exhaust gas content, which has an impact on the combustion process. Authors investigated the effect that EGR has on the in-cylinder gas temperature and reaction mechanism, focusing on NOx emission formations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

EGR Strategy for NOx Emission Reduction in a CAI Engine Fuelled with Innovative Biogas

Mariani¹,

Unich²,

Minale³

2019

IJES

View full text Add to dashboard Cite

show abstract

“…CAI combustion is triggered by auto ignition instead of by spark ignition and subsequent flame front propagation [28]. Thanks to its characteristics, CAI combustion attracted some attention in the literature [29][30][31][32]. It is characterized by the absence of a flame front propagation and by an extremely rapid evolution.…”

Section: Introductionmentioning

confidence: 99%

Combustion of Hydrogen Enriched Methane and Biogases Containing Hydrogen in a Controlled Auto-Ignition Engine

2018

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The paper describes a numerical study of the combustion of hydrogen enriched methane and biogases containing hydrogen in a Controlled Auto Ignition engine (CAI). A single cylinder CAI engine is modelled with Chemkin to predict engine performance, comparing the fuels in terms of indicated mean effective pressure, engine efficiency, and pollutant emissions. The effects of hydrogen and carbon dioxide on the combustion process are evaluated using the GRI-Mech 3.0 detailed radical chain reactions mechanism. A parametric study, performed by varying the temperature at the start of compression and the equivalence ratio, allows evaluating the temperature requirements for all fuels; moreover, the effect of hydrogen enrichment on the auto-ignition process is investigated. The results show that, at constant initial temperature, hydrogen promotes the ignition, which then occurs earlier, as a consequence of higher chemical reactivity. At a fixed indicated mean effective pressure, hydrogen presence shifts the operating range towards lower initial gas temperature and lower equivalence ratio and reduces NOx emissions. Such reduction, somewhat counter-intuitive if compared with similar studies on spark-ignition engines, is the result of operating the engine at lower initial gas temperatures.

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“…RCMs [2][3][4][5][6][7][8][9][10][11][12][13][14] and rapid compression and expansion machines (RCEMs) [15][16][17][18][19] can be classified on the basis of whether they can perform an expansion stroke. The distinguishing characteristic of RCM from RCEM is that when the piston of the RCM moves to the top dead center (TDC), the piston gets locked (including driving gas pressure locking or mechanical locking) without an expansion process, such that a constant volume combustion chamber is formed.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, as regards to the transmission mode, RCMs can be classified into linear connecting rod [2][3][4], free-piston [14,19], and crankshaft and connecting rod types [15,17].…”

Section: Introductionmentioning

confidence: 99%

Performance Characterization and Auto-Ignition Performance of a Rapid Compression Machine

et al. 2014

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Abstract:A rapid compression machine (RCM) test bench is developed in this study. The performance characterization and auto-ignition performance tests are conducted at an initial temperature of 293 K, a compression ratio of 9.5 to 16.5, a compressed temperature of 650 K to 850 K, a driving gas pressure range of 0.25 MPa to 0.7 MPa, an initial pressure of 0.04 MPa to 0.09 MPa, and a nitrogen dilution ratio of 35% to 65%. A new type of hydraulic piston is used to address the problem in which the hydraulic buffer adversely affects the rapid compression process. Auto-ignition performance tests of the RCM are then performed using a DME-O2-N2 mixture. The two-stage ignition delay and negative temperature coefficient (NTC) behavior of the mixture are observed. The effects of driving gas pressure, compression ratio, initial pressure, and nitrogen dilution ratio on the two-stage ignition delay are investigated. Results show that both the first-stage and overall ignition delays tend to increase with increasing driving gas pressure. The driving gas pressure within a certain range does not significantly influence the compressed pressure. With increasing compression ratio, the first-stage ignition delay is shortened, whereas the second-stage ignition delay is extended. With increasing initial pressure, both the first-stage and second-stage ignition delays are shortened. The second-stage ignition delay is shortened to a greater extent than that of the first-stage. With increasing nitrogen dilution ratio, the first-stage ignition delay is shortened, whereas the second-stage is extended. Thus, overall ignition delay presents different trends under various compression ratios and compressed pressure conditions. OPEN ACCESSEnergies 2014, 7 6084

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Controlled auto-ignition characteristics of methane–air mixture in a rapid intake compression and expansion machine

Cited by 14 publications

References 24 publications

EGR Strategy for NOx Emission Reduction in a CAI Engine Fuelled with Innovative Biogas

EGR Strategy for NOx Emission Reduction in a CAI Engine Fuelled with Innovative Biogas

Combustion of Hydrogen Enriched Methane and Biogases Containing Hydrogen in a Controlled Auto-Ignition Engine

Performance Characterization and Auto-Ignition Performance of a Rapid Compression Machine

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