scholarly journals Influence of injection pressure on performance and emission characteristics of single cylinder RCCI engine fuelled with ethanol gasoline and diesel biodiesel blends

2021 ◽  
Vol 2070 (1) ◽  
pp. 012160
Author(s):  
V S Kumbhar ◽  
A S Shahare ◽  
G K Awari

Abstract Reactivity controlled compression ignition (RCCI) has great potential for a simultaneous reduction in Nitrogen oxides (NOx) and particulate matter (PM) with increase in thermal efficiency. In this experimentation, an attempt is made to investigate the effect of injection pressure on the performance emission and combustion characteristics of single cylinder RCCI engine. Literature reveals that injection pressure has a great influence on the quality of charge preparation, fuel stratification, and incylinder reactivity. Suitably modified engine was operated for 0 to 12 kg loads, for 400 to 700 injection pressure. The blend of ethanol gasoline E20 used as a low reactivity fuel and blend of diesel jatropha biodiesel B20 used as a high reactivity fuel. Experimental results showed that increase in injection pressure enhances the degree of charge homogeneity, reduces the combustion duration, and provides higher rate of energy release. For 12 kg load and 700 bar injection pressure, it is observed that 5% rise in thermal efficiency, 27% reduction in smoke opacity, 2% reduction in HC, 4% reduction in CO and 20% rise in NOx as compared to 400 bar injection pressure.

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Avinash Kumar Agarwal

Fuel injection parameters such as fuel injection pressure (FIP) and start of main injection (SoMI) timings significantly affect the performance and emission characteristics of a common rail direct injection (CRDI) diesel engine. In this study, a state-of-the-art single cylinder research engine was used to investigate the effects of fuel injection parameters on combustion, performance, emission characteristics, and particulates and their morphology. The experiments were carried out at three FIPs (400, 700, and 1000 bar) and four SoMI timings (4 deg, 6 deg, 8 deg, and 10 deg bTDC) for biodiesel blends [B20 (20% v/v biodiesel and 80% v/v diesel) and B40 (40% v/v biodiesel and 60% v/v diesel)] compared to baseline mineral diesel. The experiments were performed at a constant engine speed (1500 rpm), without pilot injection and exhaust gas recirculation (EGR). The experimental results showed that FIP and SoMI timings affected the in-cylinder pressure and the heat release rate (HRR), significantly. At higher FIPs, the biodiesel blends resulted in slightly higher rate of pressure rise (RoPR) and combustion noise compared to baseline mineral diesel. All the test fuels showed relatively shorter combustion duration at higher FIPs and advanced SoMI timings. The biodiesel blends showed slightly higher NOx and smoke opacity compared to baseline mineral diesel. Lower particulate number concentration at higher FIPs was observed for all the test fuels. However, biodiesel blends showed emission of relatively higher number of particulates compared to baseline mineral diesel. Significantly lower trace metals in the particulates emitted from biodiesel blend fueled engine was an important finding of this study. The particulate morphology showed relatively smaller number of primary particles in particulate clusters from biodiesel exhaust, which resulted in relatively lower toxicity, rendering biodiesel to be more environmentally benign.


2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Wei Fang ◽  
Junhua Fang ◽  
David B. Kittelson ◽  
William F. Northrop

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion using port injection of a less reactive fuel and early-cycle direct injection (DI) of a more reactive fuel has been shown to yield both high thermal efficiency and low NOX and soot emissions over a wide engine operating range. Conventional and alternative fuels such as gasoline, natural gas, and E85 as the lower reactivity fuel in RCCI have been studied by many researchers; however, published experimental investigations of hydrous ethanol use in RCCI are scarce. Making greater use of hydrous ethanol in internal combustion engines has the potential to dramatically improve the economics and life cycle carbon dioxide emissions of using bioethanol. In this work, an experimental investigation was conducted using 150 proof hydrous ethanol as the low reactivity fuel and commercially available diesel as the high reactivity fuel in an RCCI combustion mode at various load conditions. A modified single-cylinder diesel engine was used for the experiments. Based on previous studies on RCCI combustion by other researchers, early-cycle split-injection strategy of diesel fuel was used to create an in-cylinder fuel reactivity distribution to maintain high thermal efficiency and low NOX and soot emissions. At each load condition, timing and mass fraction of the first diesel injection was held constant, while timing of the second diesel injection was swept over a range where stable combustion could be maintained. Since hydrous ethanol is highly resistant to auto-ignition and has large heat of vaporization, intake air heating was needed to obtain stable operations of the engine. The study shows that 150 proof hydrous ethanol can be used as the low reactivity fuel in RCCI through 8.6 bar indicated mean effective pressure (IMEP) and with ethanol energy fraction up to 75% while achieving simultaneously low levels of NOX and soot emissions. With increasing engine load, less intake heating is needed and exhaust gas recirculation (EGR) is required to maintain low NOX emissions.


2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Nikhil Sharma ◽  
Dev Prakash Satsangi ◽  
Avinash Kumar Agarwal

Abstract Reactivity controlled compression ignition (RCCI) mode combustion has attracted significant attention because of its superior engine performance and significantly lower emissions of oxides of nitrogen (NOx) and particulate matter (PM) compared with conventional compression ignition (CI) mode combustion engines. In this experimental study, effects of fuel injection pressure (FIP) of high reactivity fuel (HRF) and premixed ratio of low reactivity fuel (LRF) were evaluated on a diesel-methanol fueled RCCI mode combustion engine. Experiments were performed in a single cylinder research engine at a constant engine speed (1500 rpm) and constant engine load (3 bar BMEP) using three different FIPs (500, 750, and 1000 bar) of mineral diesel and four different premixed ratios (rp = 0, 0.25, 0.50, and 0.75) of methanol. Results showed that RCCI mode resulted in more stable combustion compared with baseline CI mode combustion. Increasing FIP resulted in relatively higher knocking, but it reduced with increasing premixed ratio. Relatively higher brake thermal efficiency (BTE) of RCCI mode combustion compared with baseline CI mode combustion is an important finding of this study. BTE increased with increasing FIP of mineral diesel and increasing premixed ratio of methanol. Relatively dominant effect of increasing FIP on BTE at higher premixed ratios of methanol was also an important finding of this study. RCCI mode combustion resulted in higher carbon monoxide (CO) and hydrocarbon (HC) emissions, but lower PM and NOx emissions compared with baseline CI mode combustion. Increasing FIP of HRF at lower premixed ratios reduced the number concentration of particles; however, effect of FIP became less dominant at higher premixed ratios. Relatively higher number emissions of nanoparticles at higher FIPs were observed. Statistical and qualitative correlations exhibited the importance of suitable FIP at different premixed ratios of LRF on emission characteristics of RCCI mode combustion engine.


Author(s):  
S. Gowthaman ◽  
G. Balamurugan

Homogeneous Charged Compression Ignition engine (HCCI) is a suitable replacement of conventional diesel engines as it provides higher thermal efficiency and low oxides of emission (NOx) and particulate emissions. In HCCI engine, direct controlling of ignition timing is not possible. But it can be controlled by varying the engine parameters such as fuel injection pressure, inlet air temperature and exhaust gas recirculation. In this study, HCCI engine is controlled with changing the injection pressure of the fuel and analysed for the effect of injection pressure of the fuel for emission and performance of Karanja methyl ester fuel. The experiments were conducted on HCCI engine with fuel injection pressures of 2 bar, 3 bar, 4 bar and 5 bar and the optimum fuel injection pressure is found out. The results show that, the brake thermal efficiency is increased when the injection pressure is increased due to better atomisation and fuel penetration and also resulted in low emissions (NOx, smoke) compared with diesel engine.


Author(s):  
Wei Fang ◽  
David B. Kittelson ◽  
William F. Northrop ◽  
Junhua Fang

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion using port injection of a less reactive fuel and early-cycle direct injection of a more reactive fuel has been shown to yield both high thermal efficiency and low NOX and soot emissions over a wide engine operating range. Conventional and alternative fuels such as gasoline, natural gas and E85 as the lower reactivity fuel in RCCI have been studied by many researchers; however, published experimental investigations of hydrous ethanol use in RCCI are scarce. Making greater use of hydrous ethanol in internal combustion engines has the potential to dramatically improve the economics and life cycle carbon dioxide emissions of using bio-ethanol. In this work, an experimental investigation was conducted using 150 proof hydrous ethanol as the low reactivity fuel and commercially-available diesel as the high reactivity fuel in an RCCI combustion mode at various load conditions. A modified single-cylinder diesel engine was used for the experiments. Based on previous studies on RCCI combustion by other researchers, early-cycle split-injection strategy of diesel fuel was used to create an in-cylinder fuel reactivity distribution to maintain high thermal efficiency and low NOX and soot emissions. At each load condition, timing and mass fraction of the first diesel injection was held constant, while timing of the second diesel injection was swept over a range where stable combustion could be maintained. Since hydrous ethanol is highly resistant to auto-ignition and has large heat of vaporization, intake air heating was needed to obtain stable operations of the engine. The study shows that 150 proof hydrous ethanol can be used as the low reactivity fuel in RCCI through 8.6 bar IMEP and with ethanol energy fraction up to 75% while achieving simultaneously low levels of NOX and soot emissions. With increasing engine load, less intake heating is needed and EGR is required to maintain low NOX emissions. Future work will look at stability of hydrous ethanol RCCI at higher engine load.


Work has been carried out using four stroke single cylinder diesel engine with retrofit attached with fuel injector and at optimum injection pressure 210 bar and 230 BTDC. The main purpose of using retrofit is to achieve HCCI (Homogeneous charge compression ignition) with which emissions can be reduced. Four Variants of retrofits were used and with V-cut type retrofit it was found that there is reduction in toxic emission like CO and NO but there was slight increase in HC emission when compared with normal fuel injector. Engine performance was compared with normal injector and injector with V-cut and it was found that Break thermal efficiency was increased by 0.25% at full load and 1.53% at 80% load and specific fuel consumption decreased by 0.01%.


2021 ◽  
pp. 146808742110136
Author(s):  
Huiquan Duan ◽  
Ming Jia ◽  
Jinpeng Bai ◽  
Yaopeng Li

To improve the trade-off between thermal efficiency and peak heat release rate (HRR) of partially premixed combustion (PPC) and the combustion efficiency of reactivity-controlled compression ignition (RCCI), the combustion mode with premixed high-reactivity fuel and direct-injection (DI) low-reactivity fuel, called RCCI with reverse reactivity stratification (R-RCCI), was explored at low loads in a light-duty diesel engine in this study. Compared with diesel, polyoxymethylene dimethyl ethers (PODEn) has better volatility, which is beneficial for the formation of premixed charge, so it was used as the premixed high-reactivity fuel for R-RCCI in this work. The gasoline and P20G80 (PODEn/gasoline blends with the volume fraction of 20%/80%) were respectively applied as the DI low-reactivity fuel. By investigating the combustion characteristics of R-RCCI, it is found that R-RCCI can break the trade-off between combustion efficiency and nitrogen oxides (NOx) emissions. This is because the combustion efficiency of R-RCCI is dominated by the spray location of the DI fuel rather than the 50% burn point (CA50). As the start of injection (SOI) timing is retarded, the fuel injected within the piston bowl increases, and combustion efficiency, as well as indicated thermal efficiency (ITE), is considerably promoted. Meanwhile, CA50 progressively retards with delayed SOI timing, which effectively reduces NOx emissions. The soot emissions of R-RCCI are also extremely low. The maximum ITE of PODEn/P20G80 R-RCCI is significantly higher than that of PODEn/gasoline R-RCCI. This occurs because the higher reactivity of P20G80 can reduce the sensitivity of CA50 to SOI timing and improve combustion stability, so a more delayed SOI timing is allowed to improve ITE. With the same engine configurations, R-RCCI can reduce peak pressure rise rate and improve combustion stability, while enhancing combustion efficiency and ITE compared with RCCI at the low-load conditions tested in this study.


2015 ◽  
Vol 766-767 ◽  
pp. 557-561
Author(s):  
S. Arunprasad ◽  
Thangavel Balusamy ◽  
S. Sivalakshmi

In this present paper, an attempt has been made to examine the performance and emission characteristics of a single cylinder diesel engine fueled with blends of mixed biodiesel (Thevetia peruviana, Neem, Jatropha, Pongamia). Experiments were conducted with various blends of mixed biodiesel in CI engine for different loads. The results show that lower brake thermal efficiency and higher brake specific fuel consumption were obtained with mixed biodiesel blends when compared with diesel. Lower the value of CO and HC and higher the value of CO2 emissions were determined for mixed biodiesel blends compared to that of diesel. Also, higher in NOx and lower smoke opacity were found compared to diesel.


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