Dilution Effects on Partially-Premixed Combustion of an Ultra-Low Sulphur Diesel Fuel Under Low-Load Operation

2012 ◽  
Author(s):  
Cosmin E. Dumitrescu ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wallace L. Chippior
Keyword(s):  
Oxygen Concentration ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Premixed Combustion ◽  
Start Of Injection ◽  
Partially Premixed Combustion ◽  
Partially Premixed ◽  
Heavy Duty Diesel ◽  
Hc Emissions ◽  
Dilution Effects

Dilution of partially-premixed combustion (PPC) using different combinations of excess air (λ>1) and exhaust gas recirculation (EGR) was investigated in a single-cylinder, heavy-duty diesel engine equipped with common-rail fuel injection. The experiments were limited to a single fuel injection event using ultra-low sulphur diesel fuel at a low engine load (∼3 bar BMEP) and engine speeds of 900 and 1350 rpm. The start of injection was varied to optimize the combustion performance and emissions. The experimental results show that increasing air dilution at constant EGR reduced BSFC slightly. CO and HC emissions decreased significantly due to the increased oxygen concentration, but NOx and soot emissions increased. For a given level of charge dilution, there was an optimal EGR rate to minimize BSFC. NOx emissions decreased significantly as the proportion of dilution by EGR was increased, but CO and HC emissions increased due to the reduced in-cylinder temperature and oxygen concentration, which increased the combustion duration.

Characterization of Partially Premixed Combustion With Ethanol: EGR Sweeps, Low and Maximum Loads

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Pert Tunestal
Keyword(s):  
High Efficiency ◽  
Pressure Rise ◽  
Premixed Combustion ◽  
Maximum Pressure ◽  
Pressure Rise Rate ◽  
Start Of Injection ◽  
Partially Premixed Combustion ◽  
Rise Rate ◽  
Partially Premixed ◽  
Gas Recirculation

Exhaust gas recirculation (EGR) sweeps were performed on ethanol partially premixed combustion (PPC) to show different emission and efficiency trends as compared with diesel PPC. The sweeps showed that when the EGR rate is increased, the efficiency does not diminish, HC trace is flat, and CO is low even with 45% of EGR. NOx exponentially decreases by increasing EGR while soot levels are nearly zero throughout the sweep. The EGR sweeps underlined that at high EGR levels, the pressure rise rate is a concern. To overcome this problem and keep high efficiency and low emissions, a sweep in the timing of the pilot injection and pilot-main ratio was done at ∼16.5 bars gross IMEP. It was found that with a pilot-main ratio of 50:50, and by placing the pilot at −60 with 42% of EGR, NOx and soot are below EURO VI levels; the indicated efficiency is 47% and the maximum pressure rise rate is below 10 bar/CAD. Low load conditions were examined as well. It was found that by placing the start of injection at −35 top dead center, the efficiency is maximized, on the other hand, when the injection is at −25, the emissions are minimized, and the efficiency is only 1.64% lower than its optimum value. The idle test also showed that a certain amount of EGR is needed in order to minimize the pressure rise rate.

Investigation on the Impact of Fuel Properties on Partially Premixed Combustion Characteristics in a Light Duty Diesel Engine

2012 ◽  
Author(s):  
Hadeel Solaka ◽  
Martin Tunér ◽  
Bengt Johansson
Keyword(s):  
Pressure Rise ◽  
Combustion Characteristics ◽  
Premixed Combustion ◽  
Unburned Hydrocarbon ◽  
Light Duty ◽  
Start Of Injection ◽  
Partially Premixed Combustion ◽  
Rise Rate ◽  
Partially Premixed ◽  
The Impact

The impact of fuel composition on the emission performance and combustion characteristics for partially premixed combustion (PPC) were examined for four fuels in the gasoline boiling range together with Swedish diesel MK1. Experiments were carried out at 8 bar IMEPg and 1500 rpm with 53±1% EGR and λ = 1.5. This relation gave inlet mole fractions of approximately 5% CO2 and 13% O2. The combustion phasing was adjusted by means of start of injection (SOI), for all fuels, over the range with stable combustion and acceptable pressure rise rate combined with maintained λ, EGR ratio, inlet pressure, and load. The operating range was limited by combustion instability for the high RON fuels, while MK1 and the low RON fuels could be operated over the whole MBT plateau. The largest difference in engine-out emissions between the fuels was the filtered smoke number (FSN), as the gasoline fuels produced a much lower FSN value than MK1. Higher RON value gave higher levels of carbon monoxide (CO) and unburned hydrocarbon (HC) for the gasoline fuels, while MK1 had the lowest levels of these emissions.

Fuel Stratification and Partially Premixed Combustion With Neat n-Butanol in a Compression Ignition Engine

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Shouvik Dev ◽  
Tongyang Gao ◽  
Xiao Yu ◽  
Mark Ives ◽  
Ming Zheng
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Premixed Combustion ◽  
Injection Timing ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Fuel Stratification ◽  
Partially Premixed Combustion ◽  
Partially Premixed ◽  
Ci Engines

Homogeneous charge compression ignition (HCCI) has been considered as an ideal combustion mode for compression ignition (CI) engines due to its superb thermal efficiency and low emissions of nitrogen oxides (NOx) and particulate matter. However, a challenge that limits practical applications of HCCI is the lack of control over the combustion rate. Fuel stratification and partially premixed combustion (PPC) have considerably improved the control over the heat release profile with modulations of the ratio between premixed fuel and directly injected fuel, as well as injection timing for ignition initiation. It leverages the advantages of both conventional direct injection compression ignition and HCCI. In this study, neat n-butanol is employed to generate the fuel stratification and PPC in a single cylinder CI engine. A fuel such as n-butanol can provide additional benefits of even lower emissions and can potentially lead to a reduced carbon footprint and improved energy security if produced appropriately from biomass sources. Intake port fuel injection (PFI) of neat n-butanol is used for the delivery of the premixed fuel, while the direct injection (DI) of neat n-butanol is applied to generate the fuel stratification. Effects of PFI-DI fuel ratio, DI timing, and intake pressure on the combustion are studied in detail. Different conditions are identified at which clean and efficient combustion can be achieved at a baseline load of 6 bar IMEP. An extended load of 14 bar IMEP is demonstrated using stratified combustion with combustion phasing control.

Effects of porous media on partially premixed combustion and heat transfer in meso-scale burners fuelled with ethanol

Energy ◽  
2021 ◽  
pp. 120191
Author(s):  
Xinjian Chen ◽  
Junwei Li ◽  
Dan Zhao ◽  
Muhammad Tahir Rashid ◽  
Xinyuan Zhou ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Premixed Combustion ◽  
Partially Premixed Combustion ◽  
Partially Premixed ◽  
Meso Scale
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