scholarly journals An Experimental Investigation on the Influence of Port Injection at Valve on Combustion and Emission Characteristics of B5/Biogas RCCI Engine

2020 ◽  
Vol 10 (2) ◽  
pp. 452
Author(s):  
Ibrahim B. Dalha ◽  
Mior A. Said ◽  
Zainal A. Abdul Karim ◽  
Salah E. Mohammed
Keyword(s):  
Fuel Mixture ◽  
Injection Timing ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Indicated Mean Effective Pressure ◽  
Unburned Hydrocarbon ◽  
Crank Angle ◽  
Slow Combustion ◽  
Low Load ◽  
Co Emission

High unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions, on account of the premixed air-fuel mixture entering the crevices and pre-mature combustion, are setbacks to reactivity-controlled compression ignition (RCCI) combustion at a low load. The influence of direct-injected B5 and port injection of biogas at the intake valve was, experimentally, examined in the RCCI mode. The port injection at the valve was to elevate the temperature at low load and eliminate premixing for reduced pre-mature combustion and fuel entering the crevices. An advanced injection timing of 21° crank angle before top dead centre and fraction of 50% each of the fuels, were maintained at speeds of 1600, 1800 and 2000 rpm and varied the load from 4.5 to 6.5 bar indicated mean effective pressure (IMEP). The result shows slow combustion as the load increases with the highest indicated thermal efficiency of 36.33% at 5.5 bar IMEP. The carbon dioxide and nitrogen oxides emissions increased, but UHC emission decreased, significantly, as the load increases. However, CO emission rose from 4.5 to 5.5 bar IMEP, then reduced as the load increases. The use of these fuels and biogas injection at the valve were capable of averagely reducing the persistent challenge of the CO and UHC emissions, by 20.33% and 10% respectively, compared to the conventional premixed mode.

Improving the Efficiency of Low Temperature Combustion Engines Using a Chamfered Ring-Land

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Jae Hyung Lim ◽  
Rolf D. Reitz
Keyword(s):  
Combustion Efficiency ◽  
Low Temperature Combustion ◽  
Combustion Engines ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Indicated Mean Effective Pressure ◽  
Hcci Combustion ◽  
Unburned Hydrocarbon ◽  
Piston Crown ◽  
Temperature Combustion

In the present study, a chamfered piston crown design was used in order to reduce unburned hydrocarbon (UHC) emissions from the ring-pack crevice. Compared to the conventional piston design, the chamfered piston showed 17–41% reduction in the crevice-borne UHC emissions in homogeneous charge compression ignition (HCCI) combustion. Through parametric sweeps 6 mm was identified to be a suitable chamfer size and the mechanism of the UHC reduction was revealed. Based on the findings in this study, the chamfered piston design was also tested in dual-fuel reactivity controlled compression ignition (RCCI) combustion. In the tested RCCI case using the chamfered piston the UHC and CO emissions were reduced by 79% and 36%, respectively, achieving 99.5% combustion efficiency. This also improved gross indicated thermal efficiency (gITE) from 51.1% to 51.8% in a 9 bar indicated mean effective pressure (IMEP) RCCI combustion case.

scholarly journals Impact of injection settings on gaseous emissions and particle size distribution in the dual-mode dual-fuel concept

2019 ◽  
Vol 21 (4) ◽  
pp. 561-577 ◽  
Author(s):  
Vicente Bermúdez ◽  
Vicente Macián ◽  
David Villalta ◽  
Lian Soto
Keyword(s):  
Nitrogen Oxide ◽  
Injection Pressure ◽  
Dual Fuel ◽  
Injection Timing ◽  
Compression Ignition ◽  
Dual Mode ◽  
Reactivity Controlled Compression Ignition ◽  
Accumulation Mode ◽  
Low Load ◽  
Main Injection

Reactivity controlled compression ignition concept has been highlighted among the low temperature combustion strategies. However, this combustion strategy presents some problems related to high levels of hydrocarbon and carbon monoxide emissions at low load and high-pressure rise rate at high load. Therefore, to diminish these limitations, the dual-mode dual-fuel concept has been presented as an excellent alternative. This concept uses two fuels of different reactivity and switches from a dual-fuel fully premixed strategy (based on the reactivity controlled compression ignition concept) during low load to a diffusive nature during high load operation. However, the success of dual-mode dual-fuel concept depends to a large extent on the low reactivity/high reactivity fuel ratio and the injection settings. In this study, parametric variations of injection pressure and injection timing were experimentally performed to analyze the effect over each combustion process that encompasses the dual-mode dual-fuel concept and its consequent impact on gaseous and particles emissions, including an analysis of particle size distribution. The experimental results confirm how the use of an adequate injection strategy is indispensable to obtain low exhaust emission and a balance between the different pollutants. In the fully premixed reactivity controlled compression ignition strategy, the particles concentrations were dominated by nucleation mode; however, the increase in injection pressure and the advance of the diesel main injection timing provided a simultaneous reduction of nitrogen oxide and solid particles (accumulation mode). During the highly premixed reactivity controlled compression ignition strategy, the accumulation-mode particles increased, and their concentrations were higher when the diesel main injection timing advanced and injection pressure decreased, as well as there was a slight increase in nitrogen oxide emissions. Finally, in the dual-fuel diffusion strategy, the concentrations of accumulation-mode particles were higher and there was a considerable increase of these particles with the advance of the diesel main injection timing and the reduction of the injection pressure, while the nitrogen oxide emissions decreased.

Numerical Simulation of a Naturally Aspirated Natural Gas/Diesel RCCI Engine for Investigating the Effects of Injection Timing on the Combustion and Emissions

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Amir Hossein Fakhari ◽  
Rouzbeh Shafaghat ◽  
Omid Jahanian
Keyword(s):  
Natural Gas ◽  
Fuel Mixture ◽  
Injection Timing ◽  
Reactivity Controlled Compression Ignition ◽  
Piston Bowl ◽  
Start Of Injection ◽  
Performance And Emissions ◽  
The Difference ◽  
The Impact ◽  
Co Emission

Abstract The start of injection (SOI) timing has a significant effect on increasing the homogeneity of the air–fuel mixture in an reactivity controlled compression ignition (RCCI) engine. In this paper, the impact of the SOI timing from 14 deg to 74 deg before top dead center (bTDC) and different inlet valve closing (IVC) temperatures on natural gas/diesel RCCI performance and emissions have been studied. Also, the simulations carried out by avl fire which is coupled with chemical kinetics. The results showed that in the SOIs of 14 deg, 24 deg, and 34 deg bTDC, the fuel is sprayed into the piston bowl; however, in the SOI of 44 deg bTDC, the fuel collides the bowl rim edge, because of the downward movement of the piston. With the advancement of diesel SOI timing from 14 deg to 74 deg bTDC, two different combustion trends can be observed. However, this advancement leads to a lower CO emission, but it raises the CO2 emission level. Although the pressure is a primary parameter for NOx emission, the difference between the trends of NOx and pressure plots indicates that different factors affect the NOx production and also increase the IVC temperature, and raises the in-cylinder pressure, heat release rate, NOx and CO2 emissions, while it reduces the CO emission.

scholarly journals Effect of Injection Timing and Injection Duration of Manifold Injected Fuels in Reactivity Controlled Compression Ignition Engine Operated with Renewable Fuels

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 ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Injection Timing ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Compression Ignition Engine ◽  
Compressed Natural Gas ◽  
Reactivity Controlled Compression Ignition ◽  
Brake Thermal Efficiency ◽  
Injection Duration ◽  
Fuel Mixtures

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.

scholarly journals Experimental Study of the Effect of Start of Injection and Blend Ratio on Single Fuel Reformate RCCI

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Deivanayagam Hariharan ◽  
Brian Gainey ◽  
Ziming Yan ◽  
Sotirios Mamalis ◽  
Benjamin Lawler
Keyword(s):  
Oxygen Deficiency ◽  
Fuel Mixture ◽  
Combustion Efficiency ◽  
High Reactivity ◽  
Inert Gases ◽  
Injection Timing ◽  
Indicated Mean Effective Pressure ◽  
Start Of Injection ◽  
The Difference ◽  
Blend Ratios

Abstract A new concept of single fuel reactivity-controlled compression ignition (RCCI) has been proposed through the catalytic partial oxidation (CPOX) reformation of diesel fuel. The reformed fuel mixture is then used as the low reactivity fuel and diesel itself is used as the high reactivity fuel. In this paper, two reformate mixtures from the reformation of diesel were selected for further analysis. Each reformate fuel mixture contained a significant fraction of inert gases (89% and 81%). The effects of the difference in the molar concentrations of the reformate mixtures were studied by experimenting with diesel as the direct injected fuel in RCCI over a varying start of injection timings and different blend ratios (i.e., the fraction of low and high reactivity fuels). The reformate mixture with the lower inert gas concentration had earlier combustion phasing and shorter combustion duration at any given diesel start of injection timing. The higher reactivity separation between reformate mixture and diesel, compared with gasoline and diesel, causes the combustion phasing of reformate-diesel RCCI to be more sensitive to the start of injection timing. The maximum combustion efficiency was found at a CA50 before top dead center (TDC), whereas the maximum thermal efficiency occurs at a CA50 after TDC. The range of energy-based blend ratios in which reformate-diesel RCCI is possible is between 25% and 45%, limited by ringing intensity (RI) at the low limit of blend ratios, and coefficient of variance (COV) of net indicated mean effective pressure (IMEPn) and combustion efficiency at the high limit. Intake boosting becomes necessary due to the oxygen deficiency caused by the low energy density of the reformate mixtures as it displaces intake air.

Effects of the injection parameters on the premixed charge compression ignition combustion and the emissions in a heavy-duty diesel engine

2017 ◽  
Vol 231 (7) ◽  
pp. 915-926 ◽  
Author(s):  
Yingying Lu ◽  
Wanhua Su
Keyword(s):  
Single Injection ◽  
Hydrocarbon Emissions ◽  
Injection Timing ◽  
Compression Ignition ◽  
Crank Angle ◽  
Heavy Duty Diesel Engine ◽  
Soot Emissions ◽  
Heavy Duty Diesel ◽  
Compression Ignition Combustion ◽  
Dead Centre

Numerous combustion strategies have been suggested for compression ignition engines in order to meet the stringent emission regulations with minimal sacrifice in the fuel economy. Premixed charge compression ignition combustion has the potential to reduce the nitrogen oxide emissions and the soot emissions while maintaining a high thermal efficiency and has become the research focus recently. Experiments and simulations were used to study the effects of the injection mode and the injection timing on the premixed charge compression ignition combustion and the emissions in a heavy-duty diesel engine at low and medium loads. The results reveal the following. At low loads, when the injection timing of a single injection is 35° crank angle before top dead centre because of the impinging position of the spray, the mixture is divided into two parts: the fuel above the chamber and the fuel in the piston bowl. This helps to utilize fully the in-cylinder air to form a homogeneous mixture. Also the nitrogen oxide emissions are the lowest. At medium loads, with a single injection, the injection mass is increased, the injection duration is prolonged and the mixing timing is reduced. As a result, the soot emissions, the carbon monoxide emissions and the unburned hydrocarbon emissions are increased dramatically; the best emissions are gained at an injection timing of 35° crank angle before top dead centre owing to the combined effect of the optimized mixing time and the optimized mixing space. At medium loads, with multiple injections, the injection mass is divided into four pulses, the mixing timings of which are all increased. The mixing space of the fuel–air mixture is also improved, and a more homogeneous mixture is obtained, which is beneficial to decreasing the soot emissions, the carbon monoxide emissions and the unburned hydrocarbon emissions in comparison with those for the single-injection case. When the injection timings of multiple injections are 80° crank angle before top dead centre, 65° crank angle before top dead centre, 50° crank angle before top dead centre and 35° crank angle before top dead centre, the best trade-off between the performance and the emissions can be achieved at medium loads.

scholarly journals Simulation of Combustion Process of Diesel and Ethanol Fuel in Reactivity Controlled Compression Ignition Engine

CFD letters ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 1-11
Author(s):  
Fatin Farhanah Zulkurnai ◽  
Wan Mohd Faizal Wan Mahmood ◽  
Norhidayah Mat Taib ◽  
Mohd Radzi Abu Mansor
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Combustion Process ◽  
Good Control ◽  
Injection Timing ◽  
Compression Ignition ◽  
Low Carbon ◽  
Compression Ignition Engine ◽  
Reactivity Controlled Compression Ignition ◽  
Complete Combustion

Reactivity controlled compression ignition (RCCI) engine give advantages over conventional diesel engine with the promising engine power and good control on NOx and soot emission. The trend of the RCCI concept is still new and Is very important to control the ignition in order to control the combustion progress and emission. The objective of this study is to provide data on the combustion characteristics and emission of diesel as high reactive, and ethanol as the low reactive fuel in the RCCI engine. The engine speed and injection timing were varied. Simulation work was conducted by using the Converge CFD software based on the Yanmar TF90 diesel engine parameter. Results show that operating the engine at low speed resulting in better engine performance and low carbon emissions due to the sufficient oxygen contents. For the high-speed engine, advancing the injection timing improves the fuel and air reactivity and steeper the equivalence ratio gradient, which result in a complete combustion process.

Sign in / Sign up

Export Citation Format

Share Document