Influence of Ignition Timing and EGR on the NOx Emission and the Performance of an SI Engine Fueled With Hydrogen

2015 ◽  
Author(s):  
Hassan A. Khairallah ◽  
Warren S. Vaz ◽  
Umit O. Koylu
Keyword(s):  
Hydrogen Oxidation ◽  
Engine Performance ◽  
Nox Emission ◽  
Nox Emissions ◽  
Ignition Timing ◽  
Si Engine ◽  
Nox Formation ◽  
Performance And Emission ◽  
Conflicting Objectives ◽  
Engine Power

Exhaust gas recirculation (EGR) and ignition timing have strong effects on engine performance and exhaust emissions. In the present study, detailed chemical reactions with 29 steps of hydrogen oxidation with additional nitrogen oxidation reactions were coupled with an advanced CFD code to investigate the engine performance and emission characteristics of a SI engine fueled with hydrogen. The NOx formation within the engine was computed using the extended Zeldovich mechanism with parameters adjusted for a carbon-free fuel such as hydrogen. The computational results were validated against experimental results with equivalence ratio of 0.84 and fixed ignition timing at crank angle of 5° BTDC (before top dead center). The simulations were then employed to examine the effects of EGR and ignition timing on the engine performance and NOx formation and emission. The EGR ratio was varied between 5% and 15% while the ignition timings considered were 5°, 10°, 15°, and 20° BTDC. It was found that NOx emission increased with advancing the ignition timing away from TDC while the indicated engine power showed an increasing trend with further advancing the ignition timing. Higher indicated mean effective pressure (IMEP) and indicated thermal efficiency were obtained with an advanced ignition timing of 20° BTDC. The model was also run with three different EGR ratios of 5%, 10% and 15% with fixed ignition timing at 5° BTDC. The simulation results quantified the reduction in NOx and the indicated engine power with the increase in the EGR ratio. The computations were consistent with the hypothesis that the combustion duration increases with the EGR ratio. Finally, the maximization of engine power and minimization of NOx emissions were considered as conflicting objectives. The different data points were plotted in the objective space. Using the concept of “knee”, (5° BTDC, 0% EGR) was selected as the optimal operating point representing the best trade-off between maximum engine power and minimum NOx emissions.

Emissions and Performance on a Jatropha Oil Methyl Ester Fueled Diesel Engine With Retarded Injection Timing

2013 ◽  
Author(s):  
J. G. Suryawanshi
Keyword(s):  
Methyl Ester ◽  
Diesel Engines ◽  
Direct Injection ◽  
Engine Performance ◽  
Nox Emission ◽  
Injection Timing ◽  
Nox Emissions ◽  
Jatropha Oil ◽  
Gas Temperature ◽  
Performance And Emission

Injection timing variations have a strong effect on NOx emissions for direct injection diesel engines. Retarded injection is commonly used to control NOx emissions. Biodiesel is a non-toxic, biodegradable and renewable fuel with the potential to reduce engine exhaust emissions. The methyl ester of jatropha oil, known as biodiesel, is receiving increasing attention as an alternative fuel for diesel engines. In the present investigation neat jatropha oil methyl ester (JME) as well as the blends of varying proportions of jatropha oil methyl ester (JME) and diesel were used to run a CI engine with standard injection timing and retarded injection timing. Significant improvements in engine performance and emission characteristics were observed for JME fuel. The addition of JME to diesel fuel has significantly reduced HC, CO, and smoke emissions but it increases the NOx emission slightly with standard injection timing. The NOX emission was decreased with retarded injection timing with negligible effect on fuel consumption rate. Similar trend in brake thermal efficiency and exhaust gas temperature was observed with retarded injection timing while maximum cylinder gas pressure and ignition delay was decreased.

scholarly journals Review of Performance and Emmissions Characteristics of Bio-Additive Fuel on SI Engine Fuelled by Biopetrol

2015 ◽  
Vol 773-774 ◽  
pp. 430-434
Author(s):  
Azizul Mokhtar ◽  
Nazrul Atan ◽  
Najib Rahman ◽  
Amir Khalid
Keyword(s):  
Fuel Economy ◽  
Fossil Fuels ◽  
Review Paper ◽  
Engine Performance ◽  
Exhaust Emissions ◽  
Spark Ignition Engine ◽  
Si Engine ◽  
New Approach ◽  
Performance And Emission ◽  
Performance And Emissions

Bio-additive is biodegradable and produces less air pollution thus significant for replacing the limited fossil fuels and reducing threats to the environment from exhaust emissions and global warming. Instead, the bio-additives can remarkably improve the fuel economy SI engine while operating on all kinds of fuel. Some of the bio-additive has the ability to reduce the total CO2 emission from internal petrol engine. This review paper focuses to determine a new approach in potential of bio-additives blends operating with bio-petrol on performance and emissions of spark ignition engine. It is shown that the variant in bio-additives blending ratio and engine operational condition are reduced engine-out emissions and increased efficiency. It seems that the bio-additives can increase the maximum cylinder combustion pressure, improve exhaust emissions and largely reduce the friction coefficient. The review concludes that the additives usage in bio-petrol is inseparable for the better engine performance and emission control and further research is needed to develop bio-petrol specific additives.

scholarly journals Ignition systems of combustion piston engine and possibility of its optimization

2021 ◽  
Author(s):  
Marek Vorlíček ◽  
◽  
Jozef Čerňan
Keyword(s):  
Engine Performance ◽  
Basic Definition ◽  
Ignition Timing ◽  
Piston Engine ◽  
Ignition System ◽  
System Components ◽  
Definition Of ◽  
Engine Power

This paper explains the basic definition of ignition, combustion and description of the ignition system functionality. The ignition systems are divided according to established criteriums into the most used types and descriptions of each ignition system components. It focuses on ignition timing and circumstances that affect it and how they influence the observed parameters. I am using ignition timing as an instrument for the observation and optimization of ignition. These practices are tested on piston engine in the practical part of this paper. It describes the modification of the timing curve, measuring of engine power and comparison between each curve. It is an analysis of engine performance under different conditions. The most efficient timing curve is chosen and further evaluated. The used engine for this paper was a rebuild from a car engine used in Trabant 601, VEB Automobilwerke automobile.

scholarly journals Torque and Power Characteristics of Single Piston LPG-Fueled Engines on Variations of Ignition Timing

2019 ◽  
Vol 2 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Bagiyo Condro Purnomo ◽  
Noto Widodo
Keyword(s):  
Engine Performance ◽  
Alternative Fuel ◽  
Spark Ignition ◽  
Liquefied Petroleum Gas ◽  
Ignition Timing ◽  
Si Engine ◽  
Optimum Performance ◽  
Power Characteristics

Liquefied Petroleum Gas (LPG) is an alternative fuel that has all key properties for the Spark Ignition (SI) engine. However, because of its properties, ignition timing on an LPG SI engine needs to be advanced from the reference angle to get the optimum performance. Therefore, this article presents the torque and power characteristics of a single piston LPG engine on variations of ignition timing. Evaluation of engine performance is carried out at the ignition timing of 15O, 17O, and 19O BTDC. The results showed the highest torque for LPG fuel was 10.64 Nm which was achieved at 3500 rpm with ignition timing of 19O BTDC, while the highest power for LPG fuel was 6.9 hp which was achieved at 5936 rpm with ignition timing of 19O BTDC.

Numerical Investigation of NOx Emissions Characteristics of a Natural Gas Premixed Burner Based on Chemical Reactor Network Model

2019 ◽  
Author(s):  
Bin Mu ◽  
Fulin Lei ◽  
Weiwei Shao ◽  
Xunwei Liu ◽  
Zhedian Zhang ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Chemical Reactor ◽  
Nox Emission ◽  
Recirculation Region ◽  
Nox Emissions ◽  
Nox Formation ◽  
Chemical Reactor Network ◽  
Thermal Nox ◽  
Reactor Network

Abstract Numerical optimization of nitrogen oxides (NOx) formation is an essential factor during developing low pollution combustor of gas turbine. The Computational Fluid Dynamics-Chemical Reactor Network (CFD-CRN) hybrid method has a great advantage in fast and accurate prediction of combustor NOx emissions. In this work, a hybrid CFD-CRN approach is established to predict pollutant emissions of a lean premixed model burner for gas turbine applications. Several criteria are compared for separating the combustor into chemically and physically homogeneous zones, and the crucial parameters such as residence time and flue gas recirculation ratio are calculated. The CRN model is preliminarily verified with experimental data. The effects of pressure and fuel-air unmixedness on NOx formation are subsequently investigated. In addition, the effects of changes in fuel/air flow distribution and crucial parameters of CRN model on NOx emissions are also estimated under different pressures and fuel-air unmixedness. The combustor is divided into several zones including reaction preheating region, flame front region, flame transition region, post flame region, main recirculation region and corner recirculation region based on CFD results of fuel-air mixing characteristics, velocity field, temperature field, distribution of OH mass fraction and Damkohler number. The complex CRN model has the advantage of predicting NOx emission characteristics under higher Tad conditions compared with the simple model, and its prediction of NOx emission shows good agreement with experimental data under various equivalence ratio conditions. The structure and distribution of several regions of CRN model are analogous but not significant when Reynolds number exceeds 105 under high pressure. The pathway analysis shows that the NOx emission gradually decreases through N2O and NNH mechanisms, resulted from the decreasing concentration of O radical under low Tad and high pressure. However, the pressure could significantly promote thermal NOx formation resulting form increase of temperature. The fuel-air unmixedness results in the increase of maximum flame temperature, which has significant effect on change of the CRN regions-separating. The fuel-air unmixedness causes the significant increasing of thermal NOx formation.

Investigations of DI CI engine using algal particles contained coconut biodiesel

2019 ◽  
pp. 52-61
Author(s):  
Katam Ganesh Babu ◽  
A. Veeresh Babu ◽  
K. Madhu Murthy
Keyword(s):  
Engine Performance ◽  
Calorific Value ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Third Generation ◽  
Brake Thermal Efficiency ◽  
Performance And Emission ◽  
Greenhouse Emissions ◽  
Engine Combustion ◽  
Ci Engine

Day to day increasing vehicles usage for human activities is caused to accumulate greenhouse emissions into the environment. The biodiesel is a best alternative fuel to run diesel engines. But its lower Calorific value and higher NOx emissions makes the consumer should compromise with engine performance and emission characteristics. As we know, that the use of additives to improve engine Combustion and emissions are caused to increase the fuel cost due to the higher cost of additives. The biodiesel conversion process of third generation biodiesel is costlier and required technological advancements for qualitative fuel. In the present work, the author used mixed culture micro algal particles in Coconut biodiesel (CCNME+AP) to improve engine characteristics. The Brake Thermal Efficiency (BTE) was enhanced, and the NOx emissions were less due to the absorption of heat in the Combustion chamber, it led to cool combustion phenomena with the Algal particles contained Coconut Biodiesel (CCNME+AP).

Investigation of Engine Performance and Emission Characteristics of Si Engine Fuelled with Ethanol Blends by Numerical Simulation

2014 ◽  
Vol 1016 ◽  
pp. 597-601
Author(s):  
Ceyla Ozgur ◽  
Erdi Tosun ◽  
Tayfun Ozgur ◽  
Gökhan Tuccar ◽  
Kadi̇r Aydin
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Spark Ignition Engine ◽  
Emission Characteristics ◽  
Si Engine ◽  
Performance And Emission ◽  
Performance And Emissions ◽  
Ethanol Addition ◽  
Ethanol Blends ◽  
Engine Performance And Emissions

In this study the influences of ethanol addition to gasoline on an spark ignition engine performance and emissions were explored. AVL BOOST software was used to simulate the performance and emission characteristics of different ethanol-gasoline blends. The blended fuels contain 5%, 10% and 15% of ethanol by volume, and indicated as B95E5, B90E10, and B85E15, respectively. The results showed that ethanol addition to gasoline fuel improve combustion process, decrease CO emissions and reduce BSFC of the SI engine.

NOx emissions in direct injection diesel engines: Part 2: model performance for conventional, prolonged ignition delay, and premixed charge compression ignition operating conditions

2017 ◽  
Vol 19 (5) ◽  
pp. 528-541 ◽  
Author(s):  
Clemens Brückner ◽  
Panagiotis Kyrtatos ◽  
Konstantinos Boulouchos
Keyword(s):  
Diesel Engines ◽  
Ignition Delay ◽  
Direct Injection ◽  
Operating Conditions ◽  
Premixed Combustion ◽  
Nox Emission ◽  
Nox Emissions ◽  
Nox Formation ◽  
Parameter Variations ◽  
And Diffusion

Investigations from recent years have shown that at operating conditions characterized by long ignition delays and resulting large proportions of premixed combustion, the NOx emission trend does not correspond to the (usually) postulated correlation with an appropriately defined (adiabatic) burnt flame temperature. This correlation, however, is the cornerstone of most published NOx models for direct injection diesel engines. In this light, a new phenomenological NOx model has been developed in Brückner et al. (Part 1), which considers NOx formation from products of premixed and diffusion combustion and accounts for compression heating of post-flame gases, and describes NOx formation by thermal chemistry. In this study (Part 2), the model is applied to predict NOx emissions from two medium-speed direct injection diesel engines of different size and at various operating conditions. Single parameter variations comprising sweeps of injection pressure, start of injection, load, exhaust gas recirculation rate, number of injections, and end-of-compression temperature are studied on a single-cylinder engine. In addition, different engine configurations (valve timing, turbocharger setup) and injection parameters of a marine diesel engine are investigated. For both engines and all parameter variations, the model prediction shows good agreement. Most notably, the model captures the turning point of the NOx emission trend with increasing ignition delay (first decreasing, then increasing NOx) for both engines. The differentiation in the physical treatment of the products of premixed and diffusion with increasing ignition delay showed to be essential for the model to capture the trend-reversal. Specifically, the model predicted that peak NOx formation rates in diffusion zones decrease with increasing ignition delay, whereas for the same change in ignition delay, peak formation rates in premixed zones increase. This is caused by the high energy release in short time, causing a strong compression of existing premixed combustion product zones that mix at a slower rate and have less time to mix, significantly increasing their temperature. In contrast, the model under-predicts NOx emissions for very low oxygen concentrations, in particular below 15 vol.%, which is attributed to the simple thermal NOx kinetic mechanism used. It is concluded that the new model is able to predict NOx emissions for conventional diesel combustion and for long ignition delay operating conditions, where a substantial amount of heat is released in premixed mode.

Engine Performance and Emission of Emulsified Biodiesel

2014 ◽  
Vol 607 ◽  
pp. 588-593 ◽  
Author(s):  
Amir Aziz ◽  
Ahmad Fitri Yusof ◽  
Rizalman Mamat ◽  
W.N. Azeem
Keyword(s):  
Diesel Engine ◽  
Water Content ◽  
Experimental Work ◽  
Diesel Fuel ◽  
Engine Performance ◽  
Emission Characteristics ◽  
Nox Formation ◽  
Performance And Emission ◽  
Set Up ◽  
Emulsified Biodiesel

An emulsion of biodiesel and water is one of the possible approaches that have been used to overcome diesel engine pollution. In this work, the performance and emission characteristics of a 4-cylinder diesel engine using pure diesel, biodiesel B20 and emulsified biodiesel were investigated. Emulsified biodiesel containing 5 % and 10 % water were utilize for the engine tests. During the experimental work, the engine was set-up at 2500 rpm and 20 % to 60 % loads. The result shows the reduction in NOx formation when the water content in emulsified biodiesel increased from 5 % to 10%. For the performance, there were no significant differences between the engine break powers measured for emulsified biodiesel containing 5% water and diesel fuel.

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