Multi-objective optimization of diesel injection parameters in a natural gas/diesel reactivity controlled compression ignition engine

2020 ◽  
Vol 279 ◽  
pp. 115746
Author(s):  
Tara Yazdani Motlagh ◽  
Leila N. Azadani ◽  
Kaveh Yazdani
Energy ◽  
2015 ◽  
Vol 89 ◽  
pp. 558-567 ◽  
Author(s):  
Ayatallah Gharehghani ◽  
Reza Hosseini ◽  
Mostafa Mirsalim ◽  
S. Ali Jazayeri ◽  
Talal Yusaf

2020 ◽  
pp. 146808742096121
Author(s):  
Bahram Jafari ◽  
Mahdi Seddiq ◽  
Seyyed Mostafa Mirsalim

The present paper aims to assess the impacts of diesel injection timing and two bowl geometries including re-entrant and wide-shallow combustion chambers on the combustion characteristics, emissions formation, and fuel consumption in a reactivity controlled compression ignition diesel engine under low and high load (five and nine bar indicating mean effective pressure) conditions. The results revealed that diesel injection at −60 CA ATDC under low load conditions significantly decreased soot and NOx emissions simultaneously for both piston bowl geometries. The use of the wide-shallow chamber decreased the period of the ignition delay and increased the engine operable load range as a result of more stable combustion under high-load conditions compared to the re-entrant chamber. Moreover, at all diesel injection timings, the indicated specific fuel consumption was decreased by nearly 4.8 and 6.6% under low and high load conditions, respectively when the wide-shallow combustion chamber was used since the heat transfer loss was lower than that of the re-entrant chamber. However, NOx emission under high load conditions at the center of the combustion chamber and more soot emission in the exhaust gas are two disadvantages of the wide-shallow chamber versus the re-entrant combustion chamber.


2018 ◽  
Vol 20 (8-9) ◽  
pp. 889-910 ◽  
Author(s):  
Kaveh Yazdani ◽  
Ehsan Amani ◽  
Hamid Naderan

In this study, multi-objective optimizations of a reactivity controlled compression ignition engine are performed. The main focus is the investigation of effects of seven design variables, including swirl ratio, the first and second start of injections (SOI1 and SOI2), and four injection rate-shape parameters, on the objective parameters, namely, gross indicated efficiency, the second-law efficiency, ringing intensity, and emissions. The results show that in the low swirl ratio range (swirl ratio < 1), the emissions decrease by either increasing boot length or decreasing boot velocity. The physical analysis reveals that this is due to the penetration of the high-reactivity fuel vapor in whole squish area and a large portion of the crevice. This is because the more uniform mixture in the squish region slightly mitigates the formation of hot spots and NOx, and the propagation of reaction deeper into the crevice considerably reduces carbon monoxide and unburned hydrocarbons there. The sensitivity analysis manifests that swirl ratio has the strongest effect on all objectives, and besides swirl ratio, SOI2 has the greatest impact on gross indicated efficiency and emission, while SOI1 has the strongest influence on second-law efficiency and ringing intensity. The optimal case with an advance of SOI1 and a slight retard of SOI2, that is, a longer duration between the two injections, a lower swirl ratio (of 0.5) with respect to the base case, and appropriate injection rate-shape parameters (a high boot length and low boot velocity), achieves the gross indicated efficiency of 54% and merit function of 615.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4621
Author(s):  
P. A. Harari ◽  
N. R. Banapurmath ◽  
V. S. Yaliwal ◽  
T. M. Yunus Khan ◽  
Irfan Anjum Badruddin ◽  
...  

In the current work, an effort is made to study the influence of injection timing (IT) and injection duration (ID) of manifold injected fuels (MIF) in the reactivity controlled compression ignition (RCCI) engine. Compressed natural gas (CNG) and compressed biogas (CBG) are used as the MIF along with diesel and blends of Thevetia Peruviana methyl ester (TPME) are used as the direct injected fuels (DIF). The ITs of the MIF that were studied includes 45°ATDC, 50°ATDC, and 55°ATDC. Also, present study includes impact of various IDs of the MIF such as 3, 6, and 9 ms on RCCI mode of combustion. The complete experimental work is conducted at 75% of rated power. The results show that among the different ITs studied, the D+CNG mixture exhibits higher brake thermal efficiency (BTE), about 29.32% is observed at 50° ATDC IT, which is about 1.77, 3.58, 5.56, 7.51, and 8.54% higher than D+CBG, B20+CNG, B20+CBG, B100+CNG, and B100+CBG fuel combinations. The highest BTE, about 30.25%, is found for the D+CNG fuel combination at 6 ms ID, which is about 1.69, 3.48, 5.32%, 7.24, and 9.16% higher as compared with the D+CBG, B20+CNG, B20+CBG, B100+CNG, and B100+CBG fuel combinations. At all ITs and IDs, higher emissions of nitric oxide (NOx) along with lower emissions of smoke, carbon monoxide (CO), and hydrocarbon (HC) are found for D+CNG mixture as related to other fuel mixtures. At all ITs and IDs, D+CNG gives higher In-cylinder pressure (ICP) and heat release rate (HRR) as compared with other fuel combinations.


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