scholarly journals Potential Improvement in PM-NOX Trade-Off in a Compression Ignition Engine by n-Octanol Addition and Injection Pressure

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 310
Author(s):  
Qiwei Wang ◽  
Rong Huang ◽  
Jimin Ni ◽  
Qinqing Chen

n-Octanol, as an oxygenated fuel, is considered as one of the most promising alternative fuels, owing to advantages such as its low hygroscopic nature, high cetane number, and high energy content. However, the introduction of n-octanol leads to a higher viscosity and latent heat of evaporation (LHOE), affecting the combustion and emission performances of compression ignition (CI) engines. This study sheds light on the effect of injection pressures (IPs, ranging from 60 to 160 MPa) on the combustion and emission performances of a turbocharged CI engine, in conjunction with n-octanol/diesel blends. According to the proportion of oxygen content, the test fuels contain pure diesel (N0), N2.5 (2.5% oxygen content in the blending fuels), and N5 (5% oxygen content in the blending fuels). The results indicate that the blending fuels have little influence on the in-cylinder pressure, ignition delay (ID), and CA50, but they improve the brake thermal efficiency (BTE). In terms of emissions, with the use of blending fuels, the levels of carbon monoxide (CO), soot, and nitrogen oxides (NOX) decrease, whereas emissions of hydrocarbons (HC) slightly increase. With increasing IP, the ID, brake specific fuel consumption (BSFC), HC, CO, and soot decrease significantly, and the BTE and NOX increase. In addition, the combination of n-octanol and IP improves the trade-off between NOX and soot and reduces the CO emissions.

2015 ◽  
Vol 77 (8) ◽  
Author(s):  
I. M. Yusri ◽  
M. K. Akasyah ◽  
R. Mamat ◽  
O. M. Ali

The use of biomass based renewable fuel, n-butanol blends for compression ignition (CI) engine has attracted wide attention due to its superior properties such as better miscibility, higher energy content, and cetane number as compared to other alternatives fuel. In this present study the use of n-butanol 10% blends (Bu10) with diesel fuel has been tested using multi-cylinder, 4-stroke engine with common rail direct injection system to investigate the combustion and emissions of the blended fuels. Based on the tested engine at BMEP=3.5Bar. Based on the results Bu10 fuel indicates lower first and second peak pressure by 5.4% and 2.4% for engine speed 1000rpm and 4.4% and 2.1% for engine speed 2500rpm compared to diesel fuel respectively. Percentage reduction relative to diesel fuel at engine speeds 1000rpm and 2500rpm for Bu10: Exhaust temperature was 7.5% and 5.2% respectively; Nitrogen oxides (NOx) 73.4% and 11.3% respectively.


2015 ◽  
Vol 75 (8) ◽  
Author(s):  
Helmisyah Ahmad Jalaludin ◽  
Mohd Ruysdi Ramliy ◽  
Nik Rosli Abdullah ◽  
Salmiah Kasolang ◽  
Shahrir Abdullah ◽  
...  

The sudden increase in fuel prices due to diminishing petroleum resources and the pollution resulting from its use has resulted in research into alternative fuels such as biodiesel. In addition, the faster combustion and high temperature in the combustion chamber which results from petroleum diesel fuel leads to higher nitrogen oxide (NOx) and Particulate Matter (PM) emissions. Therefore, this research was conducted to investigate the effect of using palm oil methyl ester (POME) blends as alternative fuels on the performance and emission of a compression ignition engine. The performance of POME blends and diesel were compared by manipulating the load of the engine at 1800 rpm. The results obtained show that fuel consumption rate is higher for the POME blends compared to the diesel fuel and increases as the POME concentration increases. The increment of brake specific fuel consumption and the reduction of CO emission exhibit a relation to the increase in percentage of POME. This is mainly contributed by the higher oxygen content of POME which promotes complete combustion of the blends. However, efficient combustion from the blends as compared to diesel fuel resulted from higher oxygen content and cetane number leads to significant increase in exhaust temperature. This in turn increases NOx emissions since using POME blends is highly related to high temperature of combustion chamber. The experimental results proved that POME in compression ignition engine is a possible substitute to diesel.


2003 ◽  
Author(s):  
C. Purohit ◽  
K. Aung

Increasing concerns over pollutant emissions from diesel engines have prompted researchers to find replacement fuels for diesel engines. The use of alternative fuels such as biodiesel in compression-ignition (CI) engines is beneficial to the environment as it reduces emissions of pollutants with slight penalty on the performance. This paper investigated the use of biodiesel fuel (rapeseed oil) in a CI engine by numerical simulations. The numerical simulations were based on the models of finite heat release, cylinder heat transfer, and friction losses. Simulations were carried out to evaluate the effects of compression ratio, equivalence ratio, and engine speed on the performance of the CI engine. The results of the simulations were compared with experimental data from the literature to validate the simulations. Good agreements between the computed and experimental results were obtained. The results showed that the current model could satisfactorily predict the performance of a biodiesel-fueled CI engine.


2021 ◽  
pp. 146808742110183
Author(s):  
Jonathan Martin ◽  
André Boehman

Compression-ignition (CI) engines can produce higher thermal efficiency (TE) and thus lower carbon dioxide (CO2) emissions than spark-ignition (SI) engines. Unfortunately, the overall fuel economy of CI engine vehicles is limited by their emissions of nitrogen oxides (NOx) and soot, which must be mitigated with costly, resource- and energy-intensive aftertreatment. NOx and soot could also be mitigated by adding premixed gasoline to complement the conventional, non-premixed direct injection (DI) of diesel fuel in CI engines. Several such “dual-fuel” combustion modes have been introduced in recent years, but these modes are usually studied individually at discrete conditions. This paper introduces a mapping system for dual-fuel CI modes that links together several previously studied modes across a continuous two-dimensional diagram. This system includes the conventional diesel combustion (CDC) and conventional dual-fuel (CDF) modes; the well-explored advanced combustion modes of HCCI, RCCI, PCCI, and PPCI; and a previously discovered but relatively unexplored combustion mode that is herein titled “Piston-split Dual-Fuel Combustion” or PDFC. Tests show that dual-fuel CI engines can simultaneously increase TE and lower NOx and/or soot emissions at high loads through the use of Partial HCCI (PHCCI). At low loads, PHCCI is not possible, but either PDFC or RCCI can be used to further improve NOx and/or soot emissions, albeit at slightly lower TE. These results lead to a “partial dual-fuel” multi-mode strategy of PHCCI at high loads and CDC at low loads, linked together by PDFC. Drive cycle simulations show that this strategy, when tuned to balance NOx and soot reductions, can reduce engine-out CO2 emissions by about 1% while reducing NOx and soot by about 20% each with respect to CDC. This increases emissions of unburnt hydrocarbons (UHC), still in a treatable range (2.0 g/kWh) but five times as high as CDC, requiring changes in aftertreatment strategy.


2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Jinlong Liu ◽  
Hemanth Kumar Bommisetty ◽  
Cosmin Emil Dumitrescu

Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) operation can reduce the dependence on petroleum-based fuels and curtail greenhouse gas emissions. Such an engine was converted to premixed NG spark-ignition (SI) operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector. Engine performance and combustion characteristics were investigated at several lean-burn operating conditions that changed fuel composition, spark timing, equivalence ratio, and engine speed. While the engine operation was stable, the reentrant bowl-in-piston (a characteristic of a CI engine) influenced the combustion event such as producing a significant late combustion, particularly for advanced spark timing. This was due to an important fraction of the fuel burning late in the squish region, which affected the end of combustion, the combustion duration, and the cycle-to-cycle variation. However, the lower cycle-to-cycle variation, stable combustion event, and the lack of knocking suggest a successful conversion of conventional diesel engines to NG SI operation using the approach described here.


Author(s):  
Amit Jhalani ◽  
Dilip Sharma ◽  
Pushpendra Kumar Sharma ◽  
Digambar Singh ◽  
Sumit Jhalani ◽  
...  

Diesel engines are lean burn engines; hence CO and HC emissions in the exhaust are less likely to occur in substantial amounts. The emissions of serious concern in compression ignition engines are particulate matter and nitrogen oxides because of elevated temperature conditions of combustion. Hence the researchers have strived continuously to lower down the temperature of combustion in order to bring down the emissions from CI engines. This has been tried through premixed charge compression ignition, homogeneous charge compression ignition (HCCI), gasoline compression ignition and reactivity controlled compression ignition (RCCI). In this study, an attempt has been made to critically review the literature on low-temperature combustion conditions using various conventional and alternative fuels. The problems and challenges augmented with the strategies have also been described. Water-in-diesel emulsion technology has been discussed in detail. Most of the authors agree over the positive outcomes of water-diesel emulsion for both performance and emissions simultaneously.


Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2936 ◽  
Author(s):  
Hua Tian ◽  
Jingchen Cui ◽  
Tianhao Yang ◽  
Yao Fu ◽  
Jiangping Tian ◽  
...  

Low-temperature combustions (LTCs), such as homogeneous charge compression ignition (HCCI), could achieve high thermal efficiency and low engine emissions by combining the advantages of spark-ignited (SI) engines and compression-ignited (CI) engines. Robust control of the ignition timing, however, still remains a hurdle to practical use. A novel technology of jet-controlled compression ignition (JCCI) was proposed to solve the issue. JCCI combustion phasing was controlled by hot jet formed from pre-chamber spark-ignited combustion. Experiments were done on a modified high-speed marine engine for JCCI characteristics research. The JCCI principle was verified by operating the engine individually in the mode of JCCI and in the mode of no pre-chamber jet under low- and medium-load working conditions. Effects of pre-chamber spark timing and intake charge temperature on JCCI process were tested. It was proven that the combustion phasing of the JCCI engine was closely related to the pre-chamber spark timing. A 20 °C temperature change of intake charge only caused a 2° crank angle change of the start of combustion. Extremely low nitrogen oxides (NOx) emission was achieved by JCCI combustion while keeping high thermal efficiency. The JCCI could be a promising technology for dual-fuel marine engines.


2011 ◽  
Vol 110-116 ◽  
pp. 1368-1373 ◽  
Author(s):  
Amar P. Pandhare ◽  
S. G. Wagholikar ◽  
R. B. Jadhav Sachin Musale ◽  
A. S. Padalkar

The heterogeneous catalyst are environment friendly and render the process simplified. A wide variety of solid bases have been examined for this process. The present work reports the use of hydrotalcite catalyst for the synthesis of Biodiesel from jatropha oil. An experimental investigation has been carried out to analyze the performance and emission characteristics of a compression ignition engine fuelled with Jatropha oil and its blends (10%, 20%, 40%, 50%, and 60 % ) with mineral diesel. The effect of temperature on the viscosity of Jatropha oil has also been investigated. A series of engine tests, have been conducted using each of the above fuel blends for comparative performance evaluation. The performance parameters evaluated include thermal efficiency, brake specific fuel consumption (BSFC), brake specific energy consumption (BSEC), and exhaust gas temperature whereas exhaust emissions include mass emissions of CO, HC, NO. These parameters were evaluated in a single cylinder compression ignition diesel engine. The results of the experiment in each case were compared with baseline data of mineral diesel. Significant improvements have been observed in the performance parameters of the engine as well as exhaust emissions. The gaseous emissions of oxide of nitrogen from all blends are lower than mineral diesel at all engine loads. Jatropha oil blends with diesel (up to 50% v/v) can replace diesel for operating the CI engines giving lower emissions and improved engine performance. More over results indicated that B20 have closer performance to diesel and B100 have lower brake thermal efficiency mainly due to its high viscosity compared to diesel.


Author(s):  
Gong Chen

It is always desirable for a heavy-duty compression-ignition engine, such as a diesel engine, to possess a capability of using alternate liquid fuels without significant hardware modification to the engine baseline. Because fuel properties vary between various types of liquid fuels, it is important to understand the impact and effects of the fuel properties on engine operating and output parameters. This paper intends and attempts to achieve that understanding and to predict the qualitative effects by studying analytically and qualitatively how a heavy-duty compression-ignition engine would respond to the variation of fuel properties. The fuel properties considered in this paper mainly include the fuel density, compressibility, heating value, viscosity, cetane number, and distillation temperature range. The qualitative direct and end effects of the fuel properties on engine bulk fuel injection, in-cylinder combustion, and outputs are analyzed and predicted. Understanding these effects can be useful in analyzing and designing a compression-ignition engine for using alternate liquid fuels.


2014 ◽  
Vol 612 ◽  
pp. 175-180 ◽  
Author(s):  
K.R. Patil ◽  
S.S. Thipse

Diethyl Ether (DEE) is a promising oxygenated renewable bio-base resource fuel for CI engines owing to its high ignition quality. DEE has several favourable properties, including exceptional cetane number, very low self-ignition temperature, high oxygen content, broad flammability limits and reasonable energy density for on-board storage. It is a liquid at ambient conditions, which makes it attractive for fuel handling and fuel infrastructure requirements and hence, it is a compatible fuel for use in CI engine. Diethyl ether is the simplest ether expressed by its chemical formula CH3CH2-O-CH2CH3, consisting of two ethyl groups bonded to a central oxygen atom. It can be mixed in any proportion in diesel fuel as it is completely miscible with diesel fuel. It was observed that density, kinematic viscosity and calorific value of the blends decreases while the oxygen content and cetane number of the blends increases with the concentration of DEE addition. The presence of DEE increases the front end volatility of the blends and decreases boiling point in comparison to baseline diesel fuel. No significant difference was observed in the tail-end volatility of the blends. The blended fuel retains the desirable physical properties of diesel fuel but includes the cleaner burning capability of DEE.


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