A Computational Study of In-Cylinder NOx Reduction Strategies for a Compression-Ignition Engine Fueled With Diesel/Hydrogen Mixtures

Author(s):  
Hassan A. Khairallah ◽  
Umit O. Koylu

Considerable efforts have been made to introduce alternative fuels for use in conventional diesel and gasoline engines. There is significant interest in adding hydrogen to a diesel engine to reduce emissions and improve efficiency. However, the main challenge associated with the use of hydrogen in diesel engines is high nitrogen oxide (NOX) emissions. In the present study, a reduced chemical kinetics mechanism, consisting of 52 reactions and 29 chemical species for n-heptane fuel combustion, was incorporated with detailed chemical kinetics consisting of 29 reactions for hydrogen as well as additional nitrogen oxidation. This reaction mechanism was coupled with 3-D advanced CFD software to investigate the performance and emission characteristics of a diesel-hydrogen dual-fuel engine. Computational results showed good agreements with the experimental results for brake thermal efficiency, CO2, CO, and NOX emissions. The model was then employed to examine the effects of exhaust gas recirculation (EGR) and N2 dilution on NOX emissions. The computational results quantified the reduction in NOX emissions with EGR and N2 dilution, and a more remarkable reduction was found with 30% N2 dilution. However, in terms of the N2 dilution, a general decreasing trend was observed for both NOX and CO2 emissions, while CO emissions increased. In relation to the EGR, the NOX emissions decreased while CO2 and CO emissions significantly increased. Additionally, the results showed that the indicated mean effective pressure (IMEP) and indicated power decreased as the N2 dilution increased. The same trend was observed for the EGR but the reduction was less compared to that of the N2 dilution.


Author(s):  
Muataz Abotabik ◽  
Richard T. Meyer

Major interests in the automotive industry include the use of alternative fuels and reduced fuel usage to address fuel supply security concerns and regulatory requirements. The majority of previous internal combustion engine (ICE) control strategies consider only the First Law of Thermodynamics (FLT). However, FLT is not able to distinguish losses in work potential due to irreversibilities, e.g., up to 25% of fuel exergy may be lost to irreversibilities. To account for these losses, the Second Law of Thermodynamics (SLT) is applicable. The SLT is used to identify the quality of an energy source via availability since not all the energy in a particular energy source is available to produce work; therefore optimal control that includes availability may be another path toward reduced fuel use. Herein, Model Predictive Control (MPC) is developed for both FLT and SLT approaches where fuel consumption is minimized in the former and availability destruction in the latter. Additionally, both include minimization of load tracking error. The controls are evaluated in the simulation of a single cylinder naturally aspirated compression ignition engine that is fueled with either 20% biodiesel and 80% diesel blend or diesel only. Control simulations at a constant engine speed and changing load profile show that the SLT approach results in higher SLT efficiency, reduced specific fuel consumption, and decreased NOx emissions. Further, compared to use of diesel only, use of the biodiesel blend resulted in less SLT efficiency, higher specific fuel consumption, and lower NOx emissions.



Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7903
Author(s):  
István Péter Kondor ◽  
Máté Zöldy ◽  
Dénes Mihály

Due to the world’s growing population, the size of areas intended for food production in many countries of the world can only be achieved through severe environmental damage and deforestation, which has many other detrimental consequences in addition to accelerating global warming. By replacing the bio-content of fuels with other alternative fuels, land that is used for energy crops can also be used to grow food, thus mitigating the damaging effects of deforestation. Waste-based tire pyrolysis oil (TPO) can be a promising solution to replace the bio-proportion of diesel fuel. Since it is made from waste tires, it is also an optimal solution for recycling waste. This research shows the effect of different low-volume-percent tire pyrolyzed oil blended with diesel on the performance, fuel consumption, and emissions on a Mitsubishi S4S-DT industrial diesel engine. Four different premixed ratios of TPO were investigated (2.5%, 5%, 7.5% and 10%) as well as pyrolysis oil and 100% diesel oil; however, the following studies will only include the data from the pure diesel and the 10% TPO measurements. The experimental investigations were in an AVL electric dynamometer, the soot measurements were in an AVL (Anstalt für Verbrennungskraftmaschinen List) Micro soot sensor (MSS), and the emission measurements were in a AVL Furier-transform infrared spectroscopy (FTIR) taken. The scope of research was to investigate the effect of low volume percentage TPO on performance and emissions on a light-duty diesel engine.



Mechanika ◽  
2019 ◽  
Vol 25 (5) ◽  
pp. 413-418
Author(s):  
Gopinath Varudharajan

In the present work on unheated Corn oil methyl ester and Preheated Corn oil methyl ester is used to prepare different concentration blends with diesel, B20, B40 and B60 were used as alternative fuels in a compression ignition engine. The properties like calorific value, flash point, fire point and viscosity of these oils were determined. The viscosity of corn oils has been reduced through transterification process. The waste heat energy from the exhaust gas was reused to preheat the corn oil around 80°C by adjusting the flow rate of exhaust gas.  The performance and emission characteristics of a single cylinder, direct injection diesel engine were determined using unheated corn oil, Preheated Corn oil and diesel. Brake thermal efficiency of preheated B20 was more than other blends and unheated fuels but equal to diesel fuel. Brake specific fuel consumption, CO2 and HC of preheated B20 were less than unheated fuels and diesel. However, the NOx emission of preheated B20 was little higher than unheated fuels and diesel due to high combustion temperature. By considering the result of all the factors, preheated B20 blend was found to be a suitable alternative for diesel fuel.



A computational study on performance and exhaust emissions from a 4-stroke DI CI engine using different air induction methods was carried out. Using AVL Boost IC engine simulation software a model was developed with a Naturally Aspirated (NA) air induction mode, the second model was developed by incorporating a turbocharger (TC) and again a third model was developed by the introduction of a turbocharger along with an intercooler (TCI). The individual effects of all the three air induction methods on the performance and emission of engine were studied and compared. The power output for the engine with TCI was observed to be 7.8% more than that of an engine with TC, where as it was even greater i-e 20% more when compared with NA engine. Similar Improved results for torque were also observed in case of an engine with TCI. It was also observed that emissions were higher with TCI followed with TC and NA.



In this contemporary era it is mandatory to increasing the usage of non edible biodiesel to replace the fossil fuels. This non edible biodiesels are produced from vegetable oils which is clean burning and renewable. This paper deals with the performance and emission characteristics on diesel engine with blends of Castor oil as biodiesel. Castor oil biodiesel is prepared by the use of adding 1% v/v H2SO4 after the transesterification process. The engine tests were performed with various blends B20, B40, B60 on a single cylinder, 4-stroke, diesel engine. The result shows Higher performance and lower emissions for B20 than the diesel and other blends. The brake thermal efficiency is higher than the diesel and CO, HC and NOX emissions were 22%, 8.4%, and 21% lesser than that of diesel.



Author(s):  
K. R. Balasubramanian ◽  
R. Anand ◽  
B. Venkatesh ◽  
G. R. Kannan ◽  
S. P. Sivapirakasam

The world needs an alternative fuels that could maintain the world running on its wheels due to the increasing energy demand and uncertainty in availability of the fossil fuels. The present investigation analyzes the scope of utilizing the Deccan hemp oil based biodiesel derived from jute seed as an alternative to the diesel. Experimental investigation was carried out at diesel engine with different loads from 0% to 100% and 10% overload condition under a constant speed of 1500 rpm. It was found that the reduction in brake thermal efficiency and higher brake specific fuel consumption was observed with biodiesel in comparison with diesel. The carbon monoxide (CO), carbon-dioxide (CO2), unburnt hydrocarbon (HC) and nitric oxide (NO) emissions for Deccan hemp oil based biodiesel were reduced by 0.2% vol, 1.6% vol, 62.5%, 36.84% whereas slightly higher smoke emission was observed when compared to diesel fuel. These studies revealed that Deccan hemp oil based biodiesel can be used as a fuel in compression ignition engine without any engine modifications.



2021 ◽  
Vol 39 (3) ◽  
pp. 919-924
Author(s):  
Ufaith Qadiri ◽  
Amjad Ali Pasha ◽  
Mustafa Mutiur Rahman ◽  
Mohammed Abdul Raheem ◽  
Abdul Gani Abdul Jameel ◽  
...  

In this contribution, the investigation conducted on alternative fuels includes methanol 20% blended with gasoline 80% and emulsion-based fuel with the composition of gasoline 80%, ethanol 15%, and H2O 5% are compared with 100% conventional gasoline fuel. These fueled single-cylinders spark ignition engine is studied for checking their performance and emission characteristics as per future emission norms. This work is performed on One-dimensional AVL Boost Simulation Software. The simulations predicted the performance and emission characteristics were far lesser than conventional 100% gasoline. These fuels meet the strict emission regulations of Euro VII. The main purpose of this investigation is to use alternative fuels to improve the performance and emission characteristics of the single- cylinder spark ignition engine and reduce the consumption of fossil fuel reserves. This investigation led to the conclusion that by using methanol 20% in 80% gasoline and micro-emulsion, fuel improves the power, BSFC (brake specific fuel consumption), thermal efficiency and combustion properties of the single-cylinder spark-ignition engine. The CO, HC and NOx emissions were also reduced for alternative fuel than 100% gasoline fuel. The novel water-based emulsion fuel showed the lowest value of NOx emissions as compared to blended 20% methanol with 80% gasoline and 100% gasoline fuel.



Author(s):  
Sahil Gupta ◽  
Naveen Kumar ◽  
Dhruv Gupta ◽  
Manish Vaidyanathan

Oil provides energy for 95% of transportation and the demand of transport fuel continues to rise. According to the assessment of IPCC (International Panel on Climate Change) to climate change, global oil demand will rise by 60% from 75 Mb/d in 2000 to 120 Mb/d in 2030. All countries including India are grappling with the problem of meeting the ever increasing demand of transport fuel with the constraints of international commitments, legal requirements, environmental concerns, and limited resources. Hence, search for renewable fuels is becoming more and more prominent for ensuring energy security and environmental protection. This has renewed the interest of scientific community to look for alternative fuels of bio-origin which can provide a feasible environmental friendly solution with improved performance characteristics. Biodiesel is produced by a chemical process known as transesterification, by which the triglycerides are reacted with alcohols, in the presence of a catalyst, to produce fatty acid alkyl esters. For quite some time focus for production of biodiesel has shifted towards non-edible oil feedstock from the edible ones, mostly due to food security issues. One such non-edible oil, locally known as Mahua in Indian subcontinent, may be evaluated as a potential feed stock for biodiesel production. The fuel properties were found to be comparable with that of diesel fuel. In the present study, mineral diesel fuel along with 20% (v/v %) blend of Mahua oil methyl ester (MOME) was prepared for conducting experiments and the performance and emission characteristics was investigated at 5%, 10%, 15% and 20% exhaust gas recirculation (EGR) rates. Major observations drawn from the exhaustive experiments is that the brake thermal efficiency (BTE) for M20 increased in comparison to diesel baseline whereas on employing cold EGR, BTE abridged with the increase in EGR rate. Unburned Hydrocarbon and Carbon monoxide emissions as well as Smoke Opacity upsurge with increase in EGR percentage. However, a considerable decline in NOx was obtained at higher EGR levels.



2018 ◽  
Vol 8 (2) ◽  
Author(s):  
B.Anil Kumar ◽  
K.Vijaya Kumar Reddy

Petroleum based fuels play a vital role in rapid depletion of conventional energy sources along with increasing demand and also major contributors of air pollutants. Major contributors of today’s energy demand in India is being met with fossil fuels hence it is high time that alternative fuels for engines should be derived from indigenous sources .The enormous growth of world population, increased technical development and standard of living in industrial nations has led to this intricate situation in the field of energy, supply and demand. As India is agricultural country there is wide scope for the production of vegetable oils (both edible and non edible oils) from different oil seeds. The present work is focused only on non-edible oils as fuels for engines, as the edible oils are in great demand and far too expensive. All neat oils are to be collected and converted into their respective methyl esters through transesterification process. Thermal barrier coatings are becoming increasingly important in providing thermal insulation for heat engine components. Thermal insulation reduces in-cylinder heat transfer from the engine combustion chamber as well as reducing component structural temperatures. Likewise, Bio-diesel too has a potential as a promising alternative fuel to their diesel counterparts while being renewable, sustainable, and environmental friendly. In this work, the comparative effect of performance and emission characteristics of a standard compression ignition engine (STD) with Magnesium stabilized Zirconia (MSZ) coated (LHR) engines are investigated. Fuel-related properties have to be calculated and analyzed with those of conventional diesel engine. The effect of use of bio-diesel fuel on engine power, fuel consumption and thermal efficiency has to be calculated and analysed with that of conventional diesel engine.



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