Development of a Cycle-Resolved Mechanism for Carbon Monoxide Formation

Equilibrium Concentration ◽

Reaction Scheme ◽

Operating Conditions ◽

Concentration Data ◽

Lean Burn ◽

The Impact ◽

Stroke Cycle

This paper presents an investigation into CO formation in large-bore two-stroke cycle (2SC) lean-burn engines. On March 5, 2009, the Environmental Protection Agency (EPA) proposed a new rule to addressing National Emission Standards for Hazardous Air Pollutants (HAP) for existing stationary reciprocating internal combustion engines. Specifically, the 2009 Proposed Rule identifies carbon monoxide (CO) as a surrogate for HAP and requires reductions in CO for 2SC lean-burn engines. This future promulgation has created the need for a comprehensive kinetic CO formation model. The CO model itself integrates equilibrium concentration values of CO with the CO concentration created later in the cycle from the dissociation of equilibrium CO2. The previously developed variable-geometry multi-cylinder Turbocharged-Reciprocating Engine Compressor Simulation (T-RECS) has been modified with a mechanism to model cycle-resolved CO formation using a calibrated kinetic reaction scheme. The simplified chemical kinetic CO reaction scheme has been tuned and validated with exhaust concentration data collected on a Cooper GMVC large-bore two-stroke cycle engine, and directly relates the impact of engine operating conditions and in-cylinder geometry.

Comparative study on combustion characteristics of lean premixed CH4/air mixtures in RCM using spark ignition and turbulent jet ignition in terms of orifices angular position change

Combustion Engines ◽

10.19206/ce-2019-105 ◽

2019 ◽

Vol 176 (1) ◽

pp. 36-41 ◽

Cited By ~ 1

Author(s):

Wojciech BUESCHKE ◽

Maciej SKOWRON ◽

Krzysztof WISŁOCKI ◽

Filip SZWAJCA

Keyword(s):

Positive Impact ◽

Angular Position ◽

Turbulent Jet ◽

Combustion Stability ◽

Optical Observations ◽

Charge Movement ◽

Position Change ◽

Lean Burn ◽

The increase in ignitability consist a main aim of implementation of the turbulent jet ignition (TJI) in relation to the combustion of diluted charges. Such an ignition system has been introduced to the lean-burn CNG engine in the scope of GasOn-Project (Gas Only Internal Combustion Engines). In this study the impact of TJI application on the main combustion indexes has been investigated using RCM and analyzed on the bases of the indicating and optical observations data. The images have been recorded using LaVision HSS5 camera and post-processed with Davis software. Second part of the study based on indicating measurements consist the analysis of combustion regarding the variation in the geometry of pre-chamber nozzles. It has been noted, that combustion with TJI indicates signi- ficantly bigger flame luminescence and simultaneously – faster flame front development, than the combustion initiated with conventional SI. The positive impact of nozzles angular position on engine operational data has been found in the static charge movement conditions, regarding the combustion stability.

Effect of Fuel and Air Dilution on Syngas Combustion in an Optical SI Engine

Energies ◽

10.3390/en12081566 ◽

2019 ◽

Vol 12 (8) ◽

pp. 1566 ◽

Cited By ~ 2

Author(s):

S.D. Martinez-Boggio ◽

S.S. Merola ◽

P. Teixeira Lacava ◽

A. Irimescu ◽

P.L. Curto-Risso

Keyword(s):

Combustion Process ◽

Visible Spectrum ◽

Propagation Speed ◽

Fuel Mixture ◽

Operating Conditions ◽

Inert Gases ◽

Pollutant Emissions ◽

Si Engine ◽

Lean Burn

To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved to have the potential of replacing fossil fuels in stationary internal combustion engines (ICEs). The processes associated with switching from traditional fuels to alternatives have always led to intense research efforts in order to have a broad understanding of the behavior of the engine in all operating conditions. In particular, attention needs to be focused on fuels containing relatively high concentrations of hydrogen, due to its faster propagation speed with respect to traditional fossil energy sources. Therefore, a combustion study was performed in a research optical SI engine, for a comparison between a well-established fuel such as methane (the main component of natural gas) and syngas. The main goal of this work is to study the effect of inert gases in the fuel mixture and that of air dilution during lean fuelling. Thus, two pure syngas blends (mixtures of CO and H2) and their respective diluted mixtures (CO and H2 with 50vol% of inert gases, CO2 and N2) were tested in several air-fuel ratios (stoichiometric to lean burn conditions). Initially, the combustion process was studied in detail by traditional thermodynamic analysis and then optical diagnostics were applied thanks to the optical access through the piston crown. Specifically, images were taken in the UV-visible spectrum of the entire cycle to follow the propagation of the flame front. The results show that hydrogen promotes flame propagation and reduces its distortion, as well as resulting in flames evolving closer to the spark plug. All syngas blends show a stable combustion process, even in conditions of high air and fuel dilution. In the leanest case, real syngas mixtures present a decrease in terms of performance due to significant reduction in volumetric efficiency. However, this condition strongly decreases pollutant emissions, with nitrogen oxide (NOx) concentrations almost negligible.

Effect of Trace Contaminants on PEM Fuel Cell Performance

MRS Proceedings ◽

10.1557/proc-0885-a01-05 ◽

2005 ◽

Vol 885 ◽

Cited By ~ 1

Author(s):

Tony Thampan ◽

Rick Rocheleau ◽

Keith Bethune ◽

Douglas Wheeler

Keyword(s):

Carbon Monoxide ◽

Fuel Cell ◽

Strong Dependence ◽

Pem Fuel Cells ◽

Gas Analysis ◽

Operating Conditions ◽

Test Facility ◽

Systematic Evaluation ◽

Fuel Cell Performance ◽

ABSTRACTAt the Hawaii Fuel Cell Test Facility a systematic evaluation of the impact of impurities in hydrogen is underway to evaluate the effects on the performance of PEM fuel cells. Initial tests are being conducted using carbon monoxide and hydrocarbon contaminants. The effects of carbon monoxide poisons at atmospheric and pressurized operating conditions have shown a strong dependence on concentration of the impurity over the range 6.7 µmole/mole to 29.3 µmole/mole. Additionally, benzene and toluene were tested at 20 µmole/mole. Although both benzene and toluene showed no evidence of fuel cell degradation, on-line gas analysis of the exit anode stream showed that toluene hydrogenation occurs in the anode resulting in 90% conversion of the toluene to methyl-cyclohexane.

A Specifically Designed Injector for Controlled Lube Oil Addition in View of Investigation of Pre-Ignition Phenomena in Dual–Fuel/Gas Engines

Frontiers in Mechanical Engineering ◽

10.3389/fmech.2021.623896 ◽

2021 ◽

Vol 7 ◽

Author(s):

Pascal Süess ◽

Bruno Schneider ◽

Dario Wüthrich ◽

Silas Wüthrich ◽

Kai Herrmann

Keyword(s):

Operating Conditions ◽

Test Facility ◽

Lubricating Oil ◽

Dual Fuel ◽

Ambient Conditions ◽

Lean Burn ◽

Fuel Gas ◽

Underlying Mechanisms ◽

Single Droplets

Internal combustion engines will continue to play a role during a transitional phase, especially in heavy-duty or marine applications. In this context, lean-burn gas/dual-fuel combustion is an attractive concept to reduce CO2, combined with considerably lower particulate and NOX pollution, and with efficiencies comparable to diesel combustion. However, ignition processes still pose considerable challenges, with pre-ignition in particular being a major issue. The underlying mechanisms are probably based on self-ignition of lube oil in hot zones. In order to investigate fundamentals of such phenomena in optically accessible test rigs, a novel injector was specifically developed to induce pre-ignitions artificially. The so-called “PieZo-Droplet-Injector” (PZDI) enables dosing of minor amounts of lubricating oil or even the injection of single droplets with diameters in the range of 100–200 µm. The working principle relies on a needle actuated with a piezo stack, which pushes a certain amount of lube oil in a bore so that (even single) droplets can be ejected through an adjustable nozzle. To confirm the PZDI functionality and to investigate droplet characteristics based on adjustable operating parameters, tests were performed under ambient conditions as well as in a constant volume combustion chamber under reasonable pressure and temperature conditions. Overall, the PZDI showed an excellent behavior in terms of capabilities to inject small amounts or even single droplets of lube oil. At last, this specially developed injector allows selective lube oil addition in an optically accessible engine test facility for upcoming examination of pre-ignition phenomena under real operating conditions.

Adaptive Wiebe Function Parameters for a Port-Fuel Injected Hydrogen-Fueled Engine

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2019-10031 ◽

2019 ◽

Cited By ~ 1

Author(s):

Shah Saud Alam ◽

Christopher Depcik

Keyword(s):

Experimental Data ◽

Mass Fraction ◽

Operating Conditions ◽

High Mass ◽

Parameter Determination ◽

Complete Combustion ◽

Burn Rate ◽

The Impact ◽

Wiebe Function

Abstract Current unmanned aerial vehicle (UAV) propulsion technologies includes hydrogen fuel cells, battery systems, and internal combustion engines (ICE). However, relying on a single propulsion technology might result in a limited operational range. This can be mitigated by utilizing a hybrid configuration involving a battery pack and an ICE or a fuel cell for charging. Due to its significant weight advantage and high mass-specific energy content, hydrogen (H2) is an ideal fuel for both power plant options. However, use of H2 with an ICE requires precise operational control through combustion process simulation with the predictive approximation of the mass fraction burned profile. In this area, the relatively simple single-Wiebe function is widely deployed for a variety of different fuels, as well as combustion regimes. In general, the description of the single-Wiebe function includes the extent of complete combustion (a), magnitude of the maximum burn rate (m), and combustion duration (θd). However, the literature often provides values for these parameters without necessarily relating them to operational characteristics that can influence ICE power. As a result, it is critical to correlate the burn rate of the fuel to ICE operating parameters, such as the engine compression ratio, inlet pressure, mean piston speed, exhaust gas recirculation level, equivalence ratio, and spark timing. Therefore, in an attempt to physically define these parameters, this effort performs a sensitivity analysis using linear regression (least squares method) to assess the impact of engine operating conditions on the Wiebe function in comparison to experimental data for port-fuel injected hydrogen ICEs. The result is a model that can estimate the values of a, m, and θd in combination with a relatively high coefficient of determination (R2) when compared to the experimental mass fraction burned profiles. Finally, others can expand this methodology to any experimental data for engine and fuel-specific Wiebe parameter determination.

Numerical and Experimental Investigation on an Effusion-Cooled Lean Burn Aeronautical Combustor: Aerothermal Field and Emissions

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4041676 ◽

2018 ◽

Vol 141 (4) ◽

Author(s):

L. Mazzei ◽

S. Puggelli ◽

D. Bertini ◽

A. Andreini ◽

B. Facchini ◽

...

Keyword(s):

Temperature Distribution ◽

Combustion Process ◽

Operating Conditions ◽

Pollutant Emissions ◽

Flame Spray ◽

Distribution Factor ◽

Lean Burn ◽

Radial Temperature ◽

Flamelet Generated Manifold ◽

Lean burn combustion is increasing its popularity in the aeronautical framework due to its potential in reducing drastically pollutant emissions (NOx and soot in particular). Its implementation, however, involves significant issues related to the increased amount of air dedicated to the combustion process, demanding the redesign of injection and cooling systems. Also, the conditions at the combustor exit are a concern, as high turbulence, residual swirl, and the impossibility to adjust the temperature profile with dilution holes determine a harsher environment for nozzle guide vanes. This work describes the final stages of the design of an aeronautical effusion-cooled lean burn combustor. Full annular tests were carried out to measure temperature profiles and emissions (CO and NOx) at the combustor exit. Different operating conditions of the ICAO cycle were tested, considering Idle, Cruise, Approach, and Take-off. Scale-adaptive simulations with the flamelet generated manifold (FGM) combustion model were performed to extend the validation of the employed computational fluid dynamics (CFD) methodology and to reproduce the experimental data in terms of radial temperature distribution factor (RTDF)/overall temperature distribution factor (OTDF) profiles as well as emission indexes (EIs). The satisfactory agreement paved the way to an exploitation of the methodology to provide a deeper understanding of the flow physics within the combustion chamber, highlighting the impact of the different operating conditions on flame, spray evolution, and pollutant formation.

Effect of Cylinder-by-Cylinder Variation on Performance and Gaseous Emissions of a PFI Spark Ignition Engine: Experimental and 1D Numerical Study

Applied Sciences ◽

10.3390/app11136035 ◽

2021 ◽

Vol 11 (13) ◽

pp. 6035

Author(s):

Luigi Teodosio ◽

Luca Marchitto ◽

Cinzia Tornatore ◽

Fabio Bozza ◽

Gerardo Valentino

Keyword(s):

Numerical Study ◽

Spark Ignition ◽

Operating Conditions ◽

Spark Ignition Engine ◽

Combustion Stability ◽

Pollutant Emissions ◽

Gaseous Emissions ◽

Performance And Emissions ◽

Combustion stability, engine efficiency and emissions in a multi-cylinder spark-ignition internal combustion engines can be improved through the advanced control and optimization of individual cylinder operation. In this work, experimental and numerical analyses were carried out on a twin-cylinder turbocharged port fuel injection (PFI) spark-ignition engine to evaluate the influence of cylinder-by-cylinder variation on performance and pollutant emissions. In a first stage, experimental tests are performed on the engine at different speed/load points and exhaust gas recirculation (EGR) rates, covering operating conditions typical of Worldwide harmonized Light-duty vehicles Test Cycle (WLTC). Measurements highlighted relevant differences in combustion evolution between cylinders, mainly due to non-uniform effective in-cylinder air/fuel ratio. Experimental data are utilized to validate a one-dimensional (1D) engine model, enhanced with user-defined sub-models of turbulence, combustion, heat transfer and noxious emissions. The model shows a satisfactory accuracy in reproducing the combustion evolution in each cylinder and the temperature of exhaust gases at turbine inlet. The pollutant species (HC, CO and NOx) predicted by the model show a good agreement with the ones measured at engine exhaust. Furthermore, the impact of cylinder-by-cylinder variation on gaseous emissions is also satisfactorily reproduced. The novel contribution of present work mainly consists in the extended numerical/experimental analysis on the effects of cylinder-by-cylinder variation on performance and emissions of spark-ignition engines. The proposed numerical methodology represents a valuable tool to support the engine design and calibration, with the aim to improve both performance and emissions.

ASME 2005 Internal Combustion Engine Division Fall Technical Conference (ICEF2005) ◽

An Approach for Investigating Adaptive Control Strategies to Improve Combustion Stability Under Dilute Operating Conditions

10.1115/icef2005-1283 ◽

2005 ◽

Cited By ~ 2

Author(s):

K. Dean Edwards ◽

Robert M. Wagner ◽

Timothy J. Theiss ◽

C. Stuart Daw

Keyword(s):

Adaptive Control ◽

Emission Reduction ◽

Control Strategies ◽

Fuel Efficiency ◽

Operating Conditions ◽

Combustion Stability ◽

Combustion Model ◽

Combustion Instabilities ◽

Dilute operation of internal combustion engines through lean fueling and/or high levels of exhaust gas recirculation (EGR) is frequently employed to increase fuel efficiency, reduce NOx emissions, and promote enhanced combustion modes such as HCCI. The maximum level of dilution is limited by the development of combustion instabilities that produce unacceptable levels of cycle-to-cycle combustion variability. These combustion instabilities are frequently stimulated by the nonlinear feedback associated with the residual and recirculated exhaust gases exchanged between successive cycles. However, with the application of adaptive control, it is possible to limit the severity of the combustion variability and regain efficiency and emission reduction benefits that would otherwise be lost. In order to better characterize the benefits of adaptive control, we have employed a two-zone phenomenological combustion model to simulate the onset of combustion instabilities under dilute operating conditions and illustrate the impact of these instabilities on emissions and fuel efficiency. The two-zone in-cylinder combustion model is coupled to a WAVE engine-simulation code, allowing rapid simulation of several hundred successive engine cycles with many external engine parametric effects included. By applying adaptive feedback control to the WAVE model, we demonstrate how mitigation of the extreme combustion events can result in improved efficiency and reduced emissions levels. We expect that this approach can be used to estimate the potential benefits of implementing adaptive control strategies on specific engine platforms to achieve further efficiency and emission-reduction gains.

Investigation and Optimization of Diesel Engine Outputs under Undi Biodiesel-Diesel Strategies

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4051377 ◽

2021 ◽

pp. 1-23

Author(s):

Pravin Ashok Madane ◽

Subrata Bhowmik ◽

Rajsekhar Panua ◽

P. Sandeep Varma ◽

Abhishek Paul

Keyword(s):

Carbon Monoxide ◽

Particulate Matter ◽

Diesel Engine ◽

Thermal Efficiency ◽

Operating Conditions ◽

Oxides Of Nitrogen ◽

Brake Thermal Efficiency ◽

Trade Off ◽

Unburned Hydrocarbon ◽

Abstract The present investigation accentuates the impact of Undi biodiesel blended Diesel on combustion, performance, and exhaust fume profiles of a single-cylinder, four-stroke Diesel engine. Five Undi biodiesel-Diesel blends were prepared and tested at four variable loads over a constant speed of 1500 (±10) rpm. The Undi biodiesel incorporation to Diesel notably improves the in-cylinder pressure and heat release rate of the engine. The higher amount of Undi biodiesel addition enhances the brake thermal efficiency and brake specific energy consumption of the engine. In addition, the Undi biodiesel facilitates to reduce the major pollutants, such as brake specific unburned hydrocarbon, brake specific carbon monoxide, and brake specific particulate matter emissions with slightly higher brake specific oxides of nitrogen emissions of the engine. To this end, a trade-off study was introduced to locate the favorable Diesel engine operating conditions under Undi biodiesel-Diesel strategies. The optimal Diesel engine outputs were found to be 32.65% of brake thermal efficiency, 1.21 g/kWh of brake specific cumulated oxides of nitrogen and unburned hydrocarbon, 0.94 g/kWh of brake specific carbon monoxide, and 0.32 g/kWh of brake specific particulate matter for 50% (by volume) Undi biodiesel share blend at 5.6 bar brake mean effective pressure with a relative closeness value of 0.978, which brings up the pertinence of the trade-off study in Diesel engine platforms.

Numerical and Experimental Investigation on an Effusion-Cooled Lean Burn Aeronautical Combustor: Aerothermal Field and Emissions

Volume 4B: Combustion, Fuels, and Emissions ◽

10.1115/gt2018-76765 ◽

2018 ◽

Author(s):

L. Mazzei ◽

S. Puggelli ◽

D. Bertini ◽

A. Andreini ◽

B. Facchini ◽

...

Keyword(s):

Combustion Process ◽

Operating Conditions ◽

Pollutant Emissions ◽

Combustion Model ◽

Flame Spray ◽

Lean Burn ◽

Flamelet Generated Manifold ◽

Nozzle Guide ◽

Nozzle Guide Vanes ◽

Lean burn combustion is increasing its popularity in the aeronautical framework due to its potential in reducing drastically pollutant emissions (NOx and soot in particular). Its implementation however involves significant issues related to the increased amount of air dedicated to the combustion process, demanding the redesign of injection and cooling systems. Also the conditions at the combustor exit are a concern, as high turbulence, residual swirl and the impossibility to adjust the temperature profile with dilution holes determine a harsher environment for nozzle guide vanes. This work describes the final stages of the design of an aeronautical effusion-cooled lean burn combustor. Full annular tests were carried out to measure temperature profiles and emissions (CO and NOx) at the combustor exit. Different operating conditions of the ICAO cycle were tested, considering Idle, Cruise, Approach and Take-Off. Scale-adaptive simulations with the Flamelet Generated Manifold combustion model were performed to extend the validation of the employed CFD methodology and to reproduce the experimental data in terms of RTDF/OTDF profiles as well as emission indexes. The satisfactory agreement paved the way to an exploitation of the methodology to provide a deeper understanding of the flow physics within the combustion chamber, highlighting the impact of the different operating conditions on flame, spray evolution and pollutant formation.