scholarly journals Fundamental Study on Hydrogen Low-NOx Combustion Using Exhaust Gas Self-Recirculation

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 130
Author(s):  
Kenta Kikuchi ◽  
Tsukasa Hori ◽  
Fumiteru Akamatsu
Keyword(s):  
Flame Temperature ◽  
Reduction Rate ◽  
Exhaust Gas ◽  
Fundamental Study ◽  
Recirculation Flow ◽  
City Gas ◽  
Low Nox Combustion ◽  
Hydrocarbon Gas ◽  
Gas Recirculation ◽  
The Relationship

Hydrogen is expected to be a next-generation energy source that does not emit carbon dioxide, but when used as a fuel, the issue is the increase in the amount of NOx that is caused by the increase in flame temperature. In this study, we experimentally investigated NOx emissions rate when hydrogen was burned in a hydrocarbon gas burner, which is used in a wide temperature range. As a result of the experiments, the amount of NOx when burning hydrogen in a nozzle mixed burner was twice as high as when burning city gas. However, by increasing the flow velocity of the combustion air, the amount of NOx could be reduced. In addition, by reducing the number of combustion air nozzles rather than decreasing the diameter of the air nozzles, a larger recirculation flow could be formed into the furnace, and the amount of NOx could be reduced by up to 51%. Furthermore, the amount of exhaust gas recirculation was estimated from the reduction rate of NOx, and the validity was confirmed by the relationship between adiabatic flame temperature and NOx calculated from the equilibrium calculation by chemical kinetics simulator software.

Technical Note: Investigation on emission characteristics of a compression ignition engine with oxygenated fuels and exhaust gas recirculation

2000 ◽  
Vol 214 (5) ◽  
pp. 503-508 ◽  
Author(s):  
H. W. Wang ◽  
Z. H. Huang ◽  
L. B. Zhou ◽  
D. M. Jiang ◽  
Z. L. Yang
Keyword(s):  
Linear Relationship ◽  
Reduction Rate ◽  
Exhaust Gas Recirculation ◽  
Emission Characteristics ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Mass Percentage ◽  
Compression Ignition Engine ◽  
Brake Mean Effective Pressure ◽  
Gas Recirculation

Investigations of emission characteristics were carried out on a compression ignition, dimethyl ether engine (DME) with exhaust gas recirculation (EGR) and on a diesel engine with a dimethyl carbonate (DMC) additive. The experimental results show that the DME engine with EGR can simultaneously reduce smoke and NOx emissions. The NOx can be reduced by about 20 per cent for every 10 per cent of EGR introduction, while smoke remains at zero. The diesel equivalent brake specific fuel consumption (b.s.f.c.) shows a slight decrease when DMC is added, while the effective thermal efficiency shows a slight improvement. It is found that the smoke reduction rate and smoke show a linear relationship with DMC percentage or oxygen mass percentage in the diesel fuel. For the specific brake mean effective pressure (b.m.e.p.), smoke will be reduced by 20 per cent for every 10 per cent DMC added and by 40 per cent when the oxygen mass percentage in the fuel reaches 10 per cent. The CO decreases when DMC is added, while NOx shows an increase. This difference is pronounced at a high b.m.e.p. For the specific b.m.e.p., CO and NOx show a linear relationship with DMC mass percentage in the fuel; CO will be reduced by 20 per cent while NOx will be increased by 20 per cent for every 10 per cent DMC added.

Control-Oriented Physics-Based NOX Emission Model for a Diesel Engine With Exhaust Gas Recirculation

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Saravanan Duraiarasan ◽  
Rasoul Salehi ◽  
Anna Stefanopoulou ◽  
Siddharth Mahesh ◽  
Marc Allain
Keyword(s):  
Diesel Engine ◽  
Test Procedure ◽  
Flame Temperature ◽  
Exhaust Gas Recirculation ◽  
Nox Emission ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Engine Control ◽  
Gas Recirculation ◽  
The Impact

Abstract Stringent NOX emission norm for heavy duty vehicles motivates the use of predictive models to reduce emissions of diesel engines by coordinating engine parameters and aftertreatment. In this paper, a physics-based control-oriented NOX model is presented to estimate the feedgas NOX for a diesel engine. This cycle-averaged NOX model is able to capture the impact of all major diesel engine control variables including the fuel injection timing, injection pressure, and injection rate, as well as the effect of cylinder charge dilution and intake pressure on the emissions. The impact of the cylinder charge dilution controlled by the engine exhaust gas recirculation (EGR) in the highly diluted diesel engine of this work is modeled using an adiabatic flame temperature predictor. The model structure is developed such that it can be embedded in an engine control unit without any need for an in-cylinder pressure sensor. In addition, details of this physics-based NOX model are presented along with a step-by-step model parameter identification procedure and experimental validation at both steady-state and transient conditions. Over a complete federal test procedure (FTP) cycle, on a cumulative basis the model prediction was more than 93% accurate.

NOx Emissions Modeling and Uncertainty From Exhaust-Gas-Diluted Flames

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Antonio C. A. Lipardi ◽  
Jeffrey M. Bergthorson ◽  
Gilles Bourque
Keyword(s):  
Nox Reduction ◽  
Flame Temperature ◽  
No Production ◽  
Exhaust Gas ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Kinetic And Thermodynamic Parameters ◽  
Emissions Modeling ◽  
Combustion Processes ◽  
Gas Recirculation

Oxides of nitrogen (NOx) are pollutants emitted by combustion processes during power generation and transportation that are subject to increasingly stringent regulations due to their impact on human health and the environment. One NOx reduction technology being investigated for gas-turbine engines is exhaust-gas recirculation (EGR), either through external exhaust-gas recycling or staged combustion. In this study, the effects of different percentages of EGR on NOx production will be investigated for methane–air and propane–air flames at a selected adiabatic flame temperature of 1800 K. The variability and uncertainty of the results obtained by the gri-mech 3.0 (GRI), San-Diego 2005 (SD), and the CSE thermochemical mechanisms are assessed. It was found that key parameters associated with postflame NO emissions can vary up to 192% for peak CH values, 35% for thermal NO production rate, and 81% for flame speed, depending on the mechanism used for the simulation. A linear uncertainty analysis, including both kinetic and thermodynamic parameters, demonstrates that simulated postflame nitric oxide levels have uncertainties on the order of ±50–60%. The high variability of model predictions, and their relatively high associated uncertainties, motivates future experiments of NOx formation in exhaust-gas-diluted flames under engine-relevant conditions to improve and validate combustion and NOx design tools.

Effect of Exhaust Gas Recirculation on Emissions of a Diesel Engine Fuelled with Castor Seed Biodiesel

2015 ◽  
Vol 813-814 ◽  
pp. 819-823 ◽  
Author(s):  
Pavan Bharadwaja Bhaskar ◽  
S. Srihari
Keyword(s):  
Diesel Engine ◽  
Fossil Fuels ◽  
Flame Temperature ◽  
Exhaust Gas Recirculation ◽  
Treatment Technique ◽  
Exhaust Gas ◽  
Complete Combustion ◽  
Performance And Emission ◽  
Hc Emissions ◽  
Gas Recirculation

In this study the effect on exhaust gases of a diesel engine fuelled by biodiesel and coupling Exhaust Gas Recirculation (EGR) has been done. EGR is a pre-treatment technique to trim down NOx from diesel engines as it is expected to reduce the flame temperature and the oxygen concentration in the combustion chamber. Fossil fuels so-called biodiesel is picked as the blending fuel. Existence of oxygen in Biodiesel aids complete combustion and anticipated to reduce CO and HC emissions. Exhaust Gas Recirculation technique can capably reduce the amount of NOx. EGR may tend to increase the CO and HC emissions, biodiesel which has higher oxygen content is blended to diesel so that it may compensate CO and HC emissions. The performance and emission characteristics of EGR along with biodiesel in a diesel engine are discussed.

Characterization of temporal variations and feedback timescales of exhaust gas recirculation gas properties using high-speed diode laser absorption spectroscopy for next-cycle control of cyclic variability

2018 ◽  
Vol 20 (8-9) ◽  
pp. 945-952
Author(s):  
Gurneesh S Jatana ◽  
Brian C Kaul
Keyword(s):  
High Speed ◽  
Control Strategies ◽  
Direct Injection ◽  
Exhaust Gas Recirculation ◽  
Gasoline Direct Injection ◽  
Exhaust Gas ◽  
Recirculation Flow ◽  
Cyclic Variability ◽  
Laser Absorption ◽  
Gas Recirculation

Dilute combustion offers efficiency gains in boosted gasoline direct injection engines both through knock-limit extension and thermodynamic advantages (i.e. the effect of γ on cycle efficiency), but is limited by cyclic variability at high dilution levels. Past studies have shown that the cycle-to-cycle dynamics are a combination of deterministic and stochastic effects. The deterministic causes of cyclic variations, which arise from feedback due to exhaust gas recirculation, imply the possibility of using active control strategies for dilution limit extension. While internal exhaust gas recirculation will largely provide a next-cycle effect (short-timescale feedback), the feedback of external exhaust gas recirculation will have an effect after a delay of several cycles (long timescale). Therefore, control strategies aiming to improve engine stability at dilution limit may have to account for both short- and long-timescale feedback pathways. This study shows the results of a study examining the extent to which variations in exhaust gas recirculation composition are preserved along the exhaust gas recirculation flow path and thus the relative importance and information content of the long-timescale feedback pathway. To characterize the filtering or retention of cycle-resolved feedback information, high-speed (1–5 kHz) CO2 concentration measurements were performed simultaneously at three different locations along the low-pressure external exhaust gas recirculation loop of a four-cylinder General Motors gasoline direct injection engine using a multiplexed two-color diode laser absorption spectroscopy sensor system during steady-state and transient engine operation at various exhaust gas recirculation levels. It was determined that cycle-resolved feedback propagates through internal residual gases but is filtered out by the low-pressure exhaust gas recirculation flow system and do not reach the intake manifold. Intermediate variations driven by flow rate and compositional changes are also distinguished and identified.

Combustion Characteristics of Lean Burn and Stoichiometric With Exhaust Gas Recirculation Spark-Ignited Natural Gas Engines

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Hui Xu ◽  
Leon A. LaPointe
Keyword(s):  
Natural Gas ◽  
Output Power ◽  
Flame Temperature ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Lean Burn ◽  
Brake Mean Effective Pressure ◽  
Combustion Duration ◽  
Combustion Properties ◽  
Gas Recirculation

Natural gas (NG) has been widely used in reciprocating engines for various applications such as automobile, electricity generation, and gas compression. It is in the public interest to burn fuels more efficiently and at lower exhaust emissions. NG is very suitable to serve this purpose due to its clean combustion, small carbon footprint, and, with recent breakthroughs in drilling technologies, increased availability and low cost. NG can be used in lean burn spark-ignited (LBSI) or stoichiometric EGR spark-ignited (SESI) engines. Selection of either LBSI or SESI requires accommodation of requirements such as power output/density, engine efficiency, emissions, knock margin, and cost. The work described in this paper investigated the feasibility of operating an engine originally built as an LBSI under SESI conditions. Analytical tools and workflow developed by Cummins, Inc., are used in this study. The tools require fundamental combustion properties as inputs, including laminar flame speed (LFS), adiabatic flame temperature (AFT), and auto-ignition interval (AI). These parameters provide critical information about combustion duration, engine out NOx, and relative knock propensity. An existing LBSI engine operating at its as released lambda was selected as baseline. The amount of exhaust gas recirculation (EGR) for the SESI configuration was selected so that it would have the same combustion duration as that of the LBSI at its reference lambda. One-dimensional (1D) cycle simulations were conducted under both SESI and LBSI conditions assuming constant output power, compression ratio, volumetric efficiency, heat release centroid, and brake mean effective pressure (BMEP). The 1D cycle simulations provide peak cylinder pressure (PCP) and peak unburned zone temperature (PUZT) under LBSI and SESI conditions. The results show that the SESI configuration has lower PCP but higher PUZT than that of the LBSI for the same output power. Also, for the same combustion duration, SESI has higher AFT than that of LBSI, resulting in higher engine out NOx emissions. The SESI configuration has shorter AI than that of LBSI engine, or smaller relative knock margin. Reduction of output power and emissions aftertreatment in the form of a three-way catalyst (TWC) is required to operate under SESI engine conditions.

scholarly journals Short-term and long-term adaptation algorithm for low-pressure exhaust gas recirculation estimation in spark-ignition engines

2018 ◽  
Vol 20 (4) ◽  
pp. 424-440 ◽  
Author(s):  
Konstantinos Siokos ◽  
Rohit Koli ◽  
Robert Prucka
Keyword(s):  
Exhaust Gas Recirculation ◽  
Spark Ignition ◽  
Exhaust Gas ◽  
Spark Ignition Engines ◽  
Short Term ◽  
Adaptation Algorithm ◽  
Recirculation Flow ◽  
Gas Recirculation ◽  
Estimation Models

Low-pressure exhaust gas recirculation systems are capable of increasing fuel efficiency of spark-ignition engines; however, they introduce control challenges. The low available pressure differential that drives exhaust gas recirculation flow, along with the significant pressure pulsations in the exhaust environment of a turbocharged engine hamper the accuracy of feed-forward estimation models. For that reason, feedback measurements are required in an effort to increase prediction accuracy. Additionally, the accumulation of deposits in the exhaust gas recirculation system and the aging of the valve, change the flow characteristics over time. Under these considerations, an adaptation algorithm is developed which handles both short-term (operating-point-dependent errors) and long-term (system aging) corrections for exhaust gas recirculation flow estimation. The algorithm is based on an extended Kalman filter for joint state and parameter estimation and uses the output of an intake oxygen sensor to adjust the feed-forward prediction by creating an online adaptation map. Two different exhaust gas recirculation estimation models are developed and coupled with the adaptation algorithm. The performance of the algorithm for both estimation models is evaluated in real-time through transient experiments with a turbocharged spark-ignition engine. It is demonstrated that this methodology is capable of creating an adaptation map which captures system aging, while also reduces the estimation bias by more than four times resulting in a prediction error of less than 1%. Finally, this approach proves to be a valuable tool that can significantly reduce offline calibration efforts for such models.

scholarly journals Fundamental Study of Dual Fuel on Exhaust Gas Recirculation (EGR) Operating with a Diesel Engine

2015 ◽  
Vol 773-774 ◽  
pp. 415-419 ◽  
Author(s):  
Mohd Hafizil Mat Yasin ◽  
Perowansa Paruka ◽  
Rizalman Mamat ◽  
Mohd Hafiz Ali
Keyword(s):  
Diesel Engine ◽  
Exhaust Gas Recirculation ◽  
Standard Test ◽  
Exhaust Gas ◽  
Liquefied Petroleum Gas ◽  
Gas Temperature ◽  
Fundamental Study ◽  
Operating Modes ◽  
Onboard System ◽  
Gas Recirculation

In this paper, an experimental study evaluating the effect of exhaust gas recirculation (EGR) and liquefied petroleum gas (LPG) onboard systems attached to a single cylinder DI diesel engine running with diesel is presented. Tests were performed at the minimum (1400 rpm) and maximum engine speeds (4100 rpm). The engine were tested under four different operating modes mainly; (a) standard test condition, (b) engine with EGR system, (c) engine with LPG system and (d) the engine with EGR and LPG onboard systems. Parameters that been measured during the tests are percentage of oxygen (O2) content, carbon monoxide (CO) emissions, carbon dioxide (CO2) and unburned hydrocarbon (UHC) emissions. Results show for the exhaust emissions, the engine with LPG onboard system emits higher CO and UHC emissions for both engine speeds. According to the experimental results it can be concluded that the use of EGR system increased the exhaust gas temperature and CO2emissions. While the engine with EGR and LPG onboard systems have influenced much on the increase in CO and UHC emissions for both engine speeds.

NOx Emissions Modeling and Uncertainty for Exhaust-Gas-Diluted Flames

2015 ◽  
Author(s):  
Antonio C. A. Lipardi ◽  
Jeffrey M. Bergthorson ◽  
Gilles Bourque
Keyword(s):  
Nox Reduction ◽  
Flame Temperature ◽  
No Production ◽  
Exhaust Gas ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Kinetic And Thermodynamic Parameters ◽  
Emissions Modeling ◽  
Combustion Processes ◽  
Gas Recirculation

Oxides of nitrogen (NOx) are pollutants emitted by combustion processes during power generation and transportation that are subject to increasingly-stringent regulations due to their impact on human health and the environment. One NOx reduction technology being investigated for gas-turbine engines is exhaust gas recirculation (EGR), either through external exhaust-gas recycling or staged combustion. In this study, the effects of different percentages of EGR on NOx production will be investigated for methane-air and propane-air flames at a selected adiabatic flame temperature of 1800K. The variability and uncertainty of the results obtained by the Gri-Mech 3.0, San-Diego 2005, and the CSE thermochemical mechanisms are assessed. It was found that that key parameters associated with postflame NO emissions can vary up to 192% for peak CH values, 35% for thermal NO production rate, and 81% for flame speed, depending on the mechanism used for the simulation. A linear uncertainty analysis, including both kinetic and thermodynamic parameters, demonstrates that simulated post-flame nitric oxide levels have uncertainties on the order of ±50–60%. The high variability of model predictions, and their relatively-high associated uncertainties, motivates future experiments of NOx formation in exhaust-gas-diluted flames under engine-relevant conditions to improve and validate combustion and NOx design tools.

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