scholarly journals The Effect of Iso-Octane Addition on Combustion and Emission Characteristics of a HCCI Engine Fueled With n-Heptane

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Cosmin E. Dumitrescu ◽  
Hongsheng Guo ◽  
Vahid Hosseini ◽  
W. Stuart Neill ◽  
Wallace L. Chippior ◽  
...  
Keyword(s):  
Combustion Efficiency ◽  
Liquid Volume ◽  
Emission Characteristics ◽  
Oxygenated Hydrocarbons ◽  
Hcci Engine ◽  
Fuel Blends ◽  
Hcci Combustion ◽  
Unburned Hydrocarbons ◽  
Unburned Fuel ◽  
Multizone Model

This paper investigates the effects of iso-octane addition on the combustion and emission characteristics of a single-cylinder, variable compression ratio, homogeneous charge compression ignition (HCCI) engine fueled with n-heptane. The engine was operated with four fuel blends containing up to 50% iso-octane by liquid volume at 900 rpm, 50:1 air-to-fuel ratio, no exhaust gas recirculation, and an intake mixture temperature of 30°C. A detailed analysis of the regulated and unregulated emissions was performed including validation of the experimental results using a multizone model with detailed fuel chemistry. The results show that iso-octane addition reduced HCCI combustion efficiency and retarded the combustion phasing. The range of engine compression ratios where satisfactory HCCI combustion occurred was found to narrow with increasing iso-octane percentage in the fuel. NOx emissions increased with iso-octane addition at advanced combustion phasing, but the influence of iso-octane addition was negligible once CA50 (crank angle position at which 50% heat is released) was close to or after top dead center. The total unburned hydrocarbons (THC) in the exhaust consisted primarily of alkanes, alkenes, and oxygenated hydrocarbons. The percentage of alkanes, the dominant class of THC emissions, was found to be relatively constant. The alkanes were composed primarily of unburned fuel compounds, and iso-octane addition monotonically increased and decreased the iso-octane and n-heptane percentages in the THC emissions, respectively. The percentage of alkenes in the THC was not significantly affected by iso-octane addition. Iso-octane addition increased the percentage of oxygenated hydrocarbons. Small quantities of cycloalkanes and aromatics were detected when the iso-octane percentage was increased beyond 30%.

The NOx and N2O Emission Characteristics of an HCCI Engine Operated With N-Heptane

2007 ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wally Chippior
Keyword(s):  
N2o Emission ◽  
Combustion Efficiency ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Incomplete Combustion ◽  
Hcci Combustion ◽  
Wide Range ◽  
Combustion Phase

This paper presents the NOx and N2O emission characteristics of a Cooperative Fuel Research (CFR) engine modified to operate in Homogeneous Charge Compression Ignition (HCCI) combustion mode using an air-assist port fuel injector. The single-cylinder engine was fuelled with n-heptane for these experiments. The parameters examined include intake air temperature and pressure, air/fuel ratio, compression ratio, and exhaust gas recirculation (EGR) rate. The parameters were varied in order to change the combustion phasing from advanced (knocking) to retarded (incomplete combustion) conditions. NOx emissions were less than 5 ppm for a fairly wide range of combustion phases, except when knocking or incomplete combustion occurred, and were largely unaffected by the parameter varied when the combustion phase was within the acceptable range. It was also found that NOx emissions increased significantly when retarded and incomplete combustion was observed even though lower combustion temperatures were expected. The increased N2O and unburned hydrocarbon (THC) emissions usually observed with retarded combustion phasing, as well as the deteriorated combustion efficiency, may contribute to this unexpected increase in NOx emissions. It was also shown that N2O emissions were extremely low (less than 0.5 ppm) except when incomplete combustion was observed.

Understanding the Effect of Wall Conditions and Engine Geometry on Thermal Stratification and HCCI Combustion

2014 ◽  
Author(s):  
Benjamin Lawler ◽  
Satyum Joshi ◽  
Joshua Lacey ◽  
Orgun Guralp ◽  
Paul Najt ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Heat Release ◽  
Wall Temperature ◽  
Compression Ratio ◽  
Thermal Stratification ◽  
Ceramic Coatings ◽  
Combustion Efficiency ◽  
Noticeable Effect ◽  
Hcci Engine ◽  
Hcci Combustion

Thermal stratification of the unburned charge in the cylinder has a profound effect on the burn characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine. Experimental data was collected in a single cylinder, gasoline-fueled, HCCI engine in order to determine the effects of combustion chamber geometry and wall conditions on thermal stratification and HCCI combustion. The study includes a wall temperature sweep and variations of piston top surface material, piston top geometry, and compression ratio. The data is processed with a traditional heat release routine, as well as a post-processing tool termed the Thermal Stratification Analysis, which calculates an unburned temperature distribution from heat release. For all of the sweeps, the 50% burned point was kept constant by varying the intake temperature. Keeping the combustion phasing constant ensures the separation of the effects of combustion phasing from the effects of wall conditions alone on HCCI and thermal stratification. The results for the wall temperature sweep show no changes to the burn characteristics once the combustion phasing has been matched with intake temperature. This result suggests that the effects of wall temperature on HCCI are mostly during the gas-exchange portion of the cycle. The ceramic coatings were able to very slightly decrease the thermal width, increase the burn rate, increase the combustion efficiency, and decrease the cumulative heat loss. The combustion efficiency increased with the lower surface area to volume ratio piston and the lower compression ratio. Lastly, the compression ratio comparison showed a noticeable effect on the temperature distribution due to the effect of pressure on ignition delay, and the variation of TDC temperature required to match combustion phasing.

scholarly journals The NOx and N2O Emission Characteristics of an HCCI Engine Operated With n-Heptane

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wally Chippior
Keyword(s):  
N2o Emission ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Incomplete Combustion ◽  
Hcci Combustion ◽  
Wide Range

This paper presents the oxides of nitrogen (NOx) and nitrous oxide (N2O) emission characteristics of a Cooperative Fuel Research (CFR) engine modified to operate in homogeneous charge compression ignition (HCCI) combustion mode. N-heptane was used as the fuel in this research. Several parameters were varied, including intake air temperature and pressure, air/fuel ratio (AFR), compression ratio (CR), and exhaust gas recirculation (EGR) rate, to alter the HCCI combustion phasing from an overly advanced condition where knocking occurred to an overly retarded condition where incomplete combustion occurred with excessive emissions of unburned hydrocarbons (UHC) and carbon monoxide (CO). NOx emissions below 5 ppm were obtained over a fairly wide range of operating conditions, except when knocking or incomplete combustion occurred. The NOx emissions were relatively constant when the combustion phasing was within the acceptable range. NOx emissions increased substantially when the HCCI combustion phasing was retarded beyond the optimal phasing even though lower combustion temperatures were expected. The increased N2O and UHC emissions observed with retarded combustion phasing may contribute to this unexpected increase in NOx emissions. N2O emissions were generally less than 0.5 ppm; however, they increased substantially with excessively retarded and incomplete combustion. The highest measured N2O emissions were 1.7 ppm, which occurred when the combustion efficiency was approximately 70%.

scholarly journals Influence of Silica Nano-Additives on Performance and Emission Characteristics of Soybean Biodiesel Fuelled Diesel Engine

2021 ◽  
Author(s):  
R. S. Gavhane ◽  
A. M. Kate ◽  
A. A. Pawar ◽  
Manzoore Elahi M Soudagar ◽  
Nik-Nazri Nik-Ghazali ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Combustion Efficiency ◽  
Emission Characteristics ◽  
Brake Thermal Efficiency ◽  
Performance And Emission ◽  
Fuel Blends ◽  
Soybean Biodiesel ◽  
Performance And Emissions ◽  
Nano Additives ◽  
Load Conditions

The present study examines the effect of SiO2 nano-additives on the performance and emission characteristics of a diesel engine fuelled with soybean biodiesel. Soybean biofuel was prepared using the transesterification process. Nano-additives characterisations were done using different tests such as FESEM, XRD, EDS, etc., to study the morphology of nano-additives. For proper blending of nano-additives with biodiesel, the ultrasonication process was used. Surfactant was used for the stabilisation of nano-additives. After making all the combinations of nano fuel blends, physicochemical properties were measured as per ASTM standards. Performance and emissions readings were taken at different load conditions. It was found that with the addition of SiO2 nano-additives, brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) was increased by 3.48-6.39% and 5.81-9.88%, respectively. Significant reduction of CO, CO2, NOx, and smoke emissions were also observed compared to baseline fule due to better combustion efficiency with the use of SiO2 nano-additive.

Performance and emission characteristics of a methane fuelled HCCI engine at various injection location and operating speed

2021 ◽  
Author(s):  
Jayakrishna Srinivasan ◽  
Abhishek Krishna Swamy ◽  
Pradeep Madanagopalan ◽  
Aditya Goyal ◽  
M. Santhosh Krishna ◽  
...  
Keyword(s):  
Emission Characteristics ◽  
Operating Speed ◽  
Performance And Emission ◽  
Hcci Engine ◽  
Injection Location

An experimental and modeling study to investigate effects of different injection parameters on a direct injection HCCI combustion fueled with ethanol–gasoline fuel blends

Fuel ◽  
2018 ◽  
Vol 215 ◽  
pp. 879-891 ◽  
Author(s):  
Gokhan Coskun ◽  
Usame Demir ◽  
Hakan S. Soyhan ◽  
Ali Turkcan ◽  
Ahmet N. Ozsezen ◽  
...  
Keyword(s):  
Direct Injection ◽  
Fuel Blends ◽  
Hcci Combustion ◽  
Injection Parameters ◽  
Modeling Study

NMHC and VOC Speciation of the Exhaust Gas From a Gas Turbine Engine Using Alternative, Renewable and Conventional Jet A-1 Aviation Fuels

2014 ◽  
Author(s):  
Mohamed A. Altaher ◽  
Hu Li ◽  
Simon Blakey ◽  
Winson Chung
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Aviation Fuel ◽  
Exhaust Gas ◽  
Turbine Engine ◽  
Fuel Blends ◽  
Auxiliary Power ◽  
Unburned Hydrocarbons ◽  
Full Power ◽  
Two Stages

This paper investigated the emissions of individual unburned hydrocarbons and carbonyl compounds from the exhaust gas of an APU (Auxiliary Power Unit) gas turbine engine burning various fuels. The engine was a single spool, two stages of turbines and one stage of centrifugal compressor gas turbine engine, and operated at idle and full power respectively. Four alternative aviation fuel blends with Jet A-1 were tested including GTL, hydrogenated renewable jet fuel and fatty acid ester. C2-C4 alkenes, benzene, toluene, xylene, trimethylbenzene, naphthalene, formaldehyde, acetaldehyde and acrolein emissions were measured. The results show at the full power condition, the concentrations for all hydrocarbons were very low (near or below the instrument detection limits). Formaldehyde was a major aldehyde species emitted with a fraction of around 60% of total measured aldehydes emissions. Formaldehydes emissions were reduced for all fuels compared to Jet A-1 especially at the idle conditions. There were no differences in acetaldehydes and acrolein emissions for all fuels; however, there was a noticeable reduction with GTL fuel. The aromatic hydrocarbon emissions including benzene and toluene are decreased for the alternative and renewable fuels.

A comparative numerical study of the combustion performance of the syngas-fueled HCCI engine using a toroidal piston, square bowl piston, and flat piston shape at different loads

2021 ◽  
pp. 1-27
Author(s):  
Kabbir Ali ◽  
Changup Kim ◽  
Yonggyu Lee ◽  
Seungmook Oh ◽  
Ki-Seong Kim
Keyword(s):  
Numerical Study ◽  
Pressure Rise ◽  
Fuel Mixture ◽  
Combustion Efficiency ◽  
Maximum Pressure ◽  
Cross Sectional ◽  
Combustion Performance ◽  
Hcci Engine ◽  
Heat Loss Rate ◽  
Piston Bowl

Abstract This study analyzes the combustion performance of a syngas-fueled homogenous charge compression ignition (HCCI) engine using a toroidal piston, square bowl, and flat piston shape, at low, medium, and high loads, with a constant compression ratio of 17.1. In this study, the square bowl shape is optimized by reducing the piston bowl depth and squish area ratio (squish area/cylinder cross-sectional area) from (34 to 20, 10, and 2.5) %, and compared with the flat piston shape and toroidal piston shape. This HCCI engine operates under an overly lean air–fuel mixture condition for power plant usage. ANSYS Forte CFD with GRI Mech3.0 chemical kinetics is used for combustion analysis, and the calculated results are validated by the experimental results. All simulations are accomplished at maximum brake torque (MBT) by altering the air–fuel mixture temperature at IVC with a constant equivalence ratio of 0.27. This study reveals that the main factors that affect the start of combustion , maximum pressure rise rate (MPRR), combustion efficiency, and thermal efficiency by changing the piston shape are the squish flow and reverse squish flow effects. Therefore, the square bowl piston D is the optimized piston shape that offers low MPRR and high combustion performance for the syngas-fueled HCCI engine, due to the weak squish flow and low heat loss rate through the combustion chamber wall, respectively, compared to the other piston shapes of square bowl piston A, B, and C, flat piston, and toroidal (baseline) piston shape.

scholarly journals Swirl-Can Combustor Performance to Near-Stoichiometric Fuel-Air Ratio

1976 ◽  
Author(s):  
L. A. Diehl ◽  
J. A. Biaglow
Keyword(s):  
Air Temperature ◽  
Combustion Efficiency ◽  
Oxides Of Nitrogen ◽  
Module Design ◽  
Air Temperatures ◽  
Nitrogen Emission ◽  
Unburned Hydrocarbons ◽  
Exit Temperature ◽  
And Performance ◽  
Emissions And Performance

Emissions and performance characteristics were determined for two full-annulus swirl-can modular combustors operated to near-stoichiometric fuel air ratios. The purposes of the tests were to obtain stoichiometric data at inlet-air temperatures up to 894 K and to determine the effect of module number by investigating 120 and 72 module swirl-can combustors. The maximum average exit temperature obtained with the 120-module swirl-can combustor was 2465 K with a combustion efficiency of 95 percent at an inlet-air temperature of 894 K. The 72-module swirl-can combustor reached a maximum average exit temperature of 2306 K with a combustion efficiency of 92 percent at an inlet-air temperature of 894 K. At a constant inlet air temperature, maximum oxides of nitrogen emission index values occurred at a fuel-air ratio of 0.037 for the 72-module design and 0.044 for the 120-module design. The combustor average exit temperature and combustion efficiency were calculated from emissions measurements. The measured emissions included carbon monoxide, unburned hydrocarbons, oxides of nitrogen, and smoke.

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