Investigation and Comparison of Multi Cylinder Partially Premixed Combustion Characteristics for Diesel and Gasoline Fuels

Author(s):  
Magnus Lewander ◽  
Bengt Johansson ◽  
Per Tunestal
2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Omid Askari ◽  
Hameed Metghalchi ◽  
Siamak Kazemzadeh Hannani ◽  
Ali Moghaddas ◽  
Reza Ebrahimi ◽  
...  

This study presents fundamentals of spray and partially premixed combustion characteristics of directly injected methane in a constant volume combustion chamber (CVCC). The constant volume vessel is a cylinder with inside diameter of 135 mm and inside height of 135 mm. Two end of the vessel are equipped with optical windows. A high speed complementary metal oxide semiconductor (CMOS) camera capable of capturing pictures up to 40,000 frames per second is used to observe flow conditions inside the chamber. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel–air mixture in the vessel, similar to that in a compressed natural gas (CNG) direct-injection (DI) engine. The fuel–air mixture is ignited by centrally located electrodes at a given spark delay timing of 1, 40, 75, and 110 ms. In addition to the four delay times, a 5 min waiting period was used in order to make sure of having laminar homogeneous combustion. Spray development and characterization including spray tip penetration (STP), spray cone angle (SCA), and overall equivalence ratio were investigated under 30–90 bar fuel pressures and 1–5 bar chamber pressure. Flame propagation images and combustion characteristics were determined via pressure-derived parameters and analyzed at a fuel pressure of 90 bar and a chamber pressure of 1 bar at different stratification ratios (S.R.) (from 0% to 100%) at overall equivalence ratios of 0.6, 0.8, and 1.0. Shorter combustion duration and higher combustion pressure were observed in direct injection-type combustion at all fuel air equivalence ratios compared to those of homogeneous combustion.


Author(s):  
Hadeel Solaka ◽  
Martin Tunér ◽  
Bengt Johansson

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.


Author(s):  
Omid Askari ◽  
Hameed Metghalchi ◽  
Ali Moghaddas ◽  
Siamak Kazemzadeh Hannani ◽  
Reza Ebrahimi

This study presents fundamentals of spray and partially premixed combustion characteristics of directly injected methane inside a constant volume combustion chamber (CVCC). The constant volume vessel is a cylinder with inside diameter of 135 mm and inside height of 135 mm. Two end of the vessel are equipped with optical windows. A high speed complementary metal oxide semiconductor (CMOS) camera capable of capturing pictures up to 40,000 frames per second is used to observe flow conditions inside the chamber. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel–air mixture in the vessel, similar to that in a compressed natural gas (CNG) direct injection engine. The fuel–air mixture is ignited by centrally located electrodes at a given spark delay timing of 1, 40, 75 and 110 milliseconds after fuel injection has been completed to reflect different turbulence intensities. For comparative study, by increasing the spark delay timing to five minutes, a homogeneous premixed mixture is also prepared in the vessel which provides information on laminar homogeneous mixture combustion. Spray development and characterization including spray tip penetration, spray cone angle and overall equivalence ratio were investigated under 30–90 bar fuel pressures and 1–5 bar chamber pressure. Flame propagation images and combustion characteristics were determined via pressure-derived parameters and analyzed at a fuel pressure of 90 bar and a chamber pressure of 1 bar at different stratification ratios (from 0% to 100%) at overall equivalence ratios of 0.6, 0.8 and 1.0. Shorter combustion duration and higher combustion pressure were observed in direct injection-type combustion at all fuel air equivalence ratios compared to those of homogenous combustion.


2008 ◽  
Vol 1 (1) ◽  
pp. 1063-1074 ◽  
Author(s):  
Magnus Lewander ◽  
Kent Ekholm ◽  
Bengt Johansson ◽  
Per Tunestal ◽  
Nebojsa Milovanovic ◽  
...  

Energy ◽  
2021 ◽  
pp. 120191
Author(s):  
Xinjian Chen ◽  
Junwei Li ◽  
Dan Zhao ◽  
Muhammad Tahir Rashid ◽  
Xinyuan Zhou ◽  
...  

2009 ◽  
Vol 2 (2) ◽  
pp. 71-88 ◽  
Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Per Tunestal ◽  
William Cannella

Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Pert Tunestal

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.


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