scholarly journals NOx Reduction in Diesel-Hydrogen Engines Using Different Strategies of Ammonia Injection

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1255 ◽  
Author(s):  
M.I. Lamas ◽  
C.G. Rodriguez

In order to reduce NOx emissions in internal combustion engines, the present work analyzes a measurement which consists of injecting ammonia directly into the combustion chamber. A commercial compression ignition engine fueled with a hydrogen-diesel blend was studied numerically. It was verified that the flow rate shape in which the ammonia was injected, particularly rectangular, triangular, or parabolic, as well as the injection duration had an important influence on NOx reduction. A 11.4% improvement in NOx reduction, corresponding to an overall reduction of 78.2% in NOx, was found for parabolic injection shape and 1º injection duration. The effect on carbon dioxide, carbon monoxide, and hydrocarbon emissions, as well as brake-specific consumption, was negligible.

Author(s):  
Swami Nathan Subramanian ◽  
Stephen Ciatti

The conventional combustion processes of Spark Ignition (SI) and Compression Ignition (CI) have their respective merits and demerits. Internal combustion engines use certain fuels to utilize those conventional combustion technologies. High octane fuels are required to operate the engine in SI mode, while high cetane fuels are preferable for CI mode of operation. Those conventional combustion techniques struggle to meet the current emissions norms while retaining high efficiency. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines, and conventional gasoline operated SI engines are not fuel efficient. Advanced combustion concepts have shown the potential to combine fuel efficiency and improved emissions performance. Low Temperature Combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Variations in injection pressures, injection schemes and Exhaust Gas Recirculation (EGR) are studied with low octane gasoline LTC. Reductions in emissions are a function of combustion phasing and local equivalence ratio. Engine speed, load, EGR quantity, compression ratio and fuel octane number are all factors that influence combustion phasing. Low cetane fuels have shown comparable diesel efficiencies with low NOx emissions at reasonably high power densities.


Inorganic nanotubes are attracting the attention of many scientists and investigators, due to their outstanding application potential in different fields. Researches have been performed in the field of internal combustion engines by adding nanoparticles into the diesel fuel and in biodiesel and blends and their effect on overall performance were studied. It is understood that doping of nanoparticles tend to decrease the emission levels from the engines. Owing to that idea, this project is directed to investigate the effect of doping nanoparticle over the performance and emission characteristics of a compression ignition engine. Nanotubes are mixed with diesel fuel as a fuel additive at different compositions that are 25 ppm, 50 ppm, 100 ppm to find the variation in performance and emission characteristics and results indicate that nanoparticle doped fuel shall be used as an alternate fuel without any modifications to engine structure.


2021 ◽  
pp. 146808742110387
Author(s):  
Christine Mounaïm-Rousselle ◽  
Adrien Mercier ◽  
Pierre Brequigny ◽  
Clément Dumand ◽  
Jean Bouriot ◽  
...  

Recent studies concluded that the use of ammonia in SI engines is possible thanks to an ignition booster or promoter. In this paper, the improvement of premixed ammonia/air combustion for internal combustion engines is studied as a function of performance and exhaust pollutants in a Spark-Assisted Compression Ignition single-cylinder engine, which supports a higher compression ratio (CR). For the first time, pure NH3 combustion was performed over a large range of engine operating conditions. The study concludes that neat ammonia can be used over a large operating range, here driven by the intake pressure, using a classical ignition device with a CR of 14–17 at 1000 rpm. The comparison with previous data obtained in a current single-cylinder SI engine clearly shows the potential of this engine mode, even for very low loads and various engine speeds (650, 1000, 2000 rpm), in spite of an initial aerodynamic that is not optimized to enhance flame-turbulence interaction. Kinetic simulations provide some explanations about exhaust emission behaviour, especially unburnt NH3, H2, NOx and N2O.


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.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3908
Author(s):  
Tara Larsson ◽  
Senthil Krishnan Mahendar ◽  
Anders Christiansen-Erlandsson ◽  
Ulf Olofsson

The negative impact of transport on climate has led to incentives to increase the amount of renewable fuels used in internal combustion engines (ICEs). Oxygenated, liquid biofuels are promising alternatives, as they exhibit similar combustion behaviour to gasoline. In this article, the effect of the different biofuels on engine efficiency, combustion propagation and emissions of a gasoline-optimised direct injected spark ignited (DISI) engine were evaluated through engine experiments. The experiments were performed without any engine hardware modifications. The investigated fuels are gasoline, four alcohols (methanol, ethanol, n-butanol and iso-butanol) and one ether (MTBE). All fuels were tested at two speed sweeps at low and mid load conditions, and a spark timing sweep at low load conditions. The oxygenated biofuels exhibit increased efficiencies, even at non-knock-limited conditions. At lower loads, the oxygenated fuels decrease CO, HC and NOx emissions. However, at mid load conditions, decreased volatility of the alcohols leads to increased emissions due to fuel impingement effects. Methanol exhibited the highest efficiencies and significantly increased burn rates compared to the other fuels. Gasoline exhibited the lowest level of PN and PM emissions. N-butanol and iso-butanol show significantly increased levels of particle emissions compared to the other fuels.


2016 ◽  
Vol 817 ◽  
pp. 47-56 ◽  
Author(s):  
Maciej Mikulski ◽  
Sławomir Wierzbicki ◽  
Andrzej Piętak

Improving the efficiency or work and reducing the emissions of toxic substances into the atmosphere are the two key directions of development of modern combustion engines. Improvement of engine efficiency is feasible only by increasing the precision of control thereof, which necessitates long-term operating tests. Regrettably, due to complexity of processes taking place during the combustion of fuel, these phenomena can only be tested on simulation models, based on a mathematical description of the phenomena.This paper presents the results of verification tests of the developed fuel combustion model in a multifuel compression-ignition engine for an engine running only on diesel fuel.


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