Lower Hydrocarbon Emissions Research Articles

An Energy, and Emission Assessment of Diesel Engines Powered with Shorea Robusta Biodiesel and Blends

The present investigation examines the exergy, energy, and pollutants of a diesel-powered engine fuelled with a blend of Shorea Robusta Biodiesel (SRB) and normal diesel. The impact of engine power, speed, and fuel mix on emissions and operating characteristics are investigated. The use of blended fuels including SRB reduces a number of performance metrics, including BTE, exergy efficiency, and the sustainability index. Furthermore, CO (carbon monoxide), smoke, and HC (hydrocarbon) emissions are reduced when compared to utilising pure diesel fuel. SRB20 has the lowest HC emissions among the mixes SRB. At an engine speed of 1500 rpm and a power output of 5.5kW, SRB10, SRB20, and SRB30 blends lower HC emissions by 8.92%, 10.71%, and 7.14%, respectively. Similarly, when compared to conventional diesel fuel, SRB10, SRB20, and SRB30 blends reduce CO emissions by 1.25%, 5%, and 6.25%, respectively.

CFD analysis of combustion and emission characteristics of biodiesel under conventional and late-injection based premixed combustion conditions

The simultaneous reduction in NOx and smoke emissions can be achieved with biodiesel under a late-injection based low temperature combustion (LTC) strategy. However, this occurs at the expense of a substantial increase in unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. It is worthwhile to understand the reasons behind the formation of these emissions, emphasizing comparison with conventional combustion, which is known to result in significantly low HC and CO emission levels, particularly with oxygenated biodiesel fuel. The present investigation attempts to examine the same with 3D CFD simulation. Experimental data were obtained from a light-duty diesel engine using biodiesel from non-edible Karanja oil. The unmodified engine with OEM low-pressure mechanical fuel injection system was utilized for conventional combustion operation. It is replaced with a modified common rail injection system for a late-injection-based LTC mode of operation. By combining retarded high-pressure injection with EGR, sufficient premixing was sustained to enable late injection-based premixed combustion (LI LTC). The combustion simulation was performed using CONVERGE CFD tool, utilizing a two-component surrogate of methyl butanoate (MB) and n-dodecane to represent biodiesel. A reduced chemical kinetic mechanism, developed and validated in an earlier investigation on biodiesel combustion, was utilized in the current study. The mechanism was solved using the SAGE Detailed CHEMKIN solver in CONVERGE. Validation was conducted at two engine operating conditions defining low and high loads for both combustion modes. The cylinder pressure and heat release rates were predicted with a maximum error of 1.5 and 13%, respectively. The validated CFD tool was employed to compare and analyze the equivalence ratio, in-cylinder gas temperatures, and HC and CO contours between conventional and LI LTC modes. Under LTC mode, the cylinder pressure and heat release rates were predicted with a maximum error of 10 and 15%, respectively. The comparison revealed fuel-rich regions concentrated near the bowl in conventional combustion, while the fuel was spread throughout the combustion chamber in LI LTC mode with over-rich and over-lean regions near the cylinder wall. The cylinder temperature is significantly higher for conventional combustion than LI LTC mode. The O and OH radical concentrations are higher for conventional combustion, corroborating with lower CO emissions, as they aid in CO oxidation. Fuel-rich regions contribute to increased CO emissions, whereas over-lean regions at a low-temperature result in high HC emissions, exhibited by the emission contours. Possible countermeasures to reduce high HC and CO emissions in LI LTC mode include maintaining higher coolant temperatures to enable HC and CO oxidation in the near-wall regions and fuel injection system modification to alter the air–fuel mixing.

Parametric study of GNPs nano addition in water diesel emulsified fuel on diesel engine at variable injection timings

ABSTRACT The current investigation is to determine the influence of graphene nanoplatelets (GNPs) in Water Diesel Emulsified Fuel (WDEF) of a compression ignition (CI) engine by changing injection timing (IT). The WDEF includes 94% diesel, 5% water, and 1% QPAN-80 and is referred to as D94W5Q1. For better stability, GNPs are added to D94W5Q1 at different doses (30, 60, and 90 ppm) utilizing ultrasonication, and the samples are referred to D94W5Q1-GNPs30, D94W5Q1-GNPs60, and D94W5Q1-GNPs90. The samples were run on a diesel engine at a uniform speed, fixed compression ratio (CR), and IT of 1500 rpm, 18:1, and 23°bTDC. The lower emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxide (NOx), and smoke were observed to be 61.72, 51.16, 48.45, and 25.51%, respectively, and enhanced Brake thermal efficiency (BTE) of 1.95% resulted for D94W5Q1-GNPs60, which is determined as an optimum blend. This optimum blend was evaluated further at various ITs of 19, 21, 23, and 25°bTDC, and the experimental values demonstrated higher BTE, in-cylinder pressure (CP), and heat release rate (HRR) of 3.49, 9.13, and 4.64% respectively, and reduced Brake Specific Fuel Consumption (BSFC) of 3.08%. Furthermore, the emissions were decreased for HC, CO, and smoke by 5.84, 22, and 8.91%, respectively, but the NOx value was raised by 3.01% at 25°bTDC. Finally, the D94W5Q1-GNPs60 blend at advanced IT enhances the overall engine performance.

Effect of injecting mixed-biodiesel upon performance and emission characteristics of a direct injection single fuelled diesel engine

The continued expansion in use of the transportation fuels, rising pollutants via cars, and higher costs of carbon fuels have prompted investigation into sustainable energy. Numerous renewable resources have indeed been investigated as well as experimented into internal combustion engines, including biodiesel, bio oil, biogas, and fisher trospch fuel. The morphological attributes of biofuel derived from mahua oil and jojoba oil have been investigated in this study. The resulting mixture biofuel has been combined with gasoline in various quantities and assessed for performance and exhaust emissions inside a single cylinder 4-stroke water cooled DI engine. Results depicted mixed biodiesel blend of 20% i.e. PBD20 has improved BTE (brake thermal efficiency) of 1.46% while BSFC (brake specific fuel consumption) was on higher side which increased by 6.25% when compared to diesel. Considering emission analysis, PBD20 depicts 7.72% lower hydrocarbon emission with slight increment in oxides of nitrogen by 3.05% higher than diesel at peak loading condition. The acquired findings are compared to conventional fuel and provided in this research. Jojoba oil and mahua oil have dynamic performances that are nearly identical to gasoline.

Effects of split diesel injection strategies on combustion, knocking, cyclic variations and emissions of a natural gas-diesel dual fuel medium speed engine

Accelerated by the harms and depletion risk of fossil fuels, transition to low-carbon or renewable fuels have become an urgent need for combustion engines to decarbonize transport sectors. Natural gas-diesel dual-fuel combustion is a promising method to achieve these goals by allowing the usage of natural gas in diesel engines. However, this concept has drawbacks of low combustion efficiency, high unburned hydrocarbon (HC) emissions and high cyclic variations at low engine loads. These drawbacks hinder the benefits of dual-fuel such as low NOx and soot emissions. To find solutions to these drawbacks, split diesel injections with variable injection timings and mass split ratios (ratio of first injection diesel mass to total diesel mass) were investigated experimentally and numerically on a medium speed marine engine at low load using constant natural gas and diesel amounts.Experimental results of the split injection were compared to single injection dual-fuel and conventional diesel operation. Single injection case resulted in slightly lower HC emissions and cyclic variations and higher NOx emissions than split cases in a narrow injection timing interval. Apart from that, split injections increased combustion efficiency and decreased cyclic variations in a broader timing interval. For split cases, early first injection timing prevented high premixed heat release peak, suppressed NOx emissions and knocking. Especially, using 70% split ratio with retarded second injections increased combustion efficiency, decreased knocking level and provided simultaneous reduction of HC and NOx emissions compared to lower split ratio cases. In short, despite not giving the minimum values at all conditions, split injection showed potential to find a remedy to high HC emissions and cyclic variations issues by keeping robust operation in a wider injection timing interval.The numerical results support the experiments in which better combustion and decreased HC emissions are attained using sufficiently early diesel injections. Simulations show that, compared to late single injection, early single injection dual-fuel case enables more homogeneous temperature distribution and better oxidization of methane near the cylinder wall and central region above the piston crown. Besides, split injection shows improved methane oxidation near the cylinder wall and inside top-land crevice volume.

Research on the Emission Characteristics of a Passenger Car Powered by Ethanol, Methanol, and Liquefied Petroleum Gas Under Real-World Running Conditions

Abstract Alternative fuels have gained considerable attention because of their excellent sustainable energy conservation and emission reduction characteristics. In this study, emission characteristics and fuel economy of three alternative fuels were compared for a passenger car under real-world running conditions. Specifically, the portable emission measurement system (PEMS) was used to evaluate the emission performance of 10 vol% ethanol in gasoline (E10), 15 vol% methanol in gasoline (M15), and liquefied petroleum gas (LPG). The results showed considerable variation in both gaseous and particulate emissions under different running conditions. Carbon monoxide (CO) and hydrocarbon (HC) emissions were higher on main roads, whereas particle number (PN) and particulate matter (PM) emissions were higher on expressways. Regulated emissions from the vehicle powered by three alternative fuels were lower than those of the vehicle powered by pure gasoline (G100). That is, the PN emissions of the three alternative fuels were 1–2 orders of magnitude less than those of G100, with a concomitant reduction in PM. Moreover, the proportion of nuclear-mode particles was reduced, with a maximum difference of more than 10% on expressways. LPG resulted in the cleanest gaseous and particulate emissions. M15 produced lower HC emissions than E10 because of its higher oxygen content, but led to higher carbon dioxide (CO2) and nitrogen oxides (NOx) emissions.

Performance of SI Engine under the Effect of Magnetic Field by using CNG, Petrol and Ethanol

Abstract: The invention resides within the field of treatment of hydrocarbon fuels in liquid or gaseous form, to extend the fuelburning efficiency, by exposing the fuel in containment vessels or conduits to a shaped uniform field of force with a relentless directional flux. Hydrocarbon fuels have long branched geometric chains of carbon atoms which tend to fold over onto themselves and on adjoining molecules because of inter molecular electromagnetic attraction existing between like molecules or atoms. It is vital to grasp that in a very fluid that's subjected to an external field the electron excitation (magnetic moment) occurring, affects molecular orientation. because the axis of the electrons become aligned with the external magnetic flux, the momentum of the molecule not averages intent on zero, as within the normal case in molecules not possessing permanent dipole moments. This accommodation is attributed to the very fact that on the molecular level, a spinning electron subjected to an accurate amount of electromagnetic energy will captivate that energy and "spinflip" into an aligned state. When a magnetism is applied, the instant as seen by the electron excitation, causes the molecule to tend to align with the direction of the field of force. The momentum of the molecule not averages dead set zero because the axis of the electrons aligns with the external magnetic flux, because it does in molecules without permanent dipole moments. The fluctuating dipole moments under the influence of the external flux acquire a net attraction, which produces a stronger bonding with an oxygen ion. As a result of the complex fuel, molecules tend to uncluster, straighten and produce higher combustion efficiencies. the rise in combustion efficiency is because of the unfolding of the hydrocarbon molecules which produce an increased extent for more complete oxidation of the fuel. The unfolding of the fuel molecules is that the major effect of the dipole being off from its neutral state by the applied field of force. Increased combustion yields increased fuel efficiency, with lower hydrocarbon emissions from hydrocarbon-based fuelburning apparatus. However, certain problems remain to be overcome, like whether to focus the force field con or directional alignment, determine flux strength, select appropriate magnetic materials and determine mounting arrangements for the best efficiency. The effect is to stop scaling from occurring on the inner walls of the conduit from the liquid flowing there through by forcing the molecules which might attach themselves to the inner walls of the conduit toward the middle of the conduit. Keywords: The magnetic effect, Combustion, Emissions, paramagnetic, diamagnetic, aligns & orientation, efficiency

The effect of tri-fuel blends on engine characteristics of a direct injection diesel engine with exhaust gas recirculation

ABSTRACT Biofuels are the most promising alternative to petro-diesel. In this work, the combined effect of mahua biodiesel and 1-Hexanol is studied on the engine characteristics. The concentration of both 1-Hexanol and mahua biodiesel is varied, 10%, 20%, and 30% each with diesel fuel. Common rail direct injection diesel engine is used in this study. Engine load is varied from 20% to 80% in step of 20%, the speed of the engine is constant throughout the experiment. Biofuel blends showed improved cylinder pressure and mean gas temperature at a higher engine load. At 60% load, 10H10M80D (10% 1-Hexanol/10% mahua biodiesel/80% diesel) showed 3.45% lower thermal efficiency and 6.11% higher fuel consumption compared to diesel. At 60% load, all the biofuel blends showed 50% lower carbon monoxide emission. At 60% load, 10H10M80D showed 33.33% lower hydrocarbon emission and 0.96% higher nitrogen oxide emission compared to baseline readings. The biofuel blends are less sensitive to exhaust gas recirculation (EGR) due to the oxygenated nature of biofuels. With 20% EGR, at 60% load, 10H10M80D showed 39.48% lower nitrogen oxide compared to no EGR. The results of 10H10M80D showed the best performance at all loads.

CFD-guided optimization of the injector and injection parameters for light-duty GCI engine

In this study, computational fluid dynamics (CFD) and machine learning (ML) were used to investigate the effects of and optimize the injector design parameters for light-duty gasoline compression ignition (GCI) engine. This study was performed at part- (6 bar) and high-load (22 bar) indicated mean effective pressure (IMEP) conditions. The effects of number of nozzles (nNoz), spray angle (SA) and plume angle (PA) while maintaining total nozzle area (TNA) and start of injection (SOI) were first investigated. The increased nNoz and PA enhanced fuel/air mixing, especially in the bowl region, by even spray distribution at part-load condition, but the effects are negligible at high-load mixing-driven combustion due to high in-cylinder temperature and pressure at the time of main injection. On the other hand, SA had significant effect on the air utilization and hence engine performance and emissions at both part- and high-load conditions. The best design from this manual parametric study produced a balanced air utilization between piston bowl and squish region resulting from the fuel spray targeting the upper lip of the bowl. The second phase of this study focused on the optimization of the injector and injection parameters including nNoz, SA, nozzle hole diameters (dNoz) and SOI using design of experiment (DoE) approach. 32 DoE cases were generated and best design was selected at each load point. It was found that the SA and SOI are the most influential injection parameters. Specifically, two optimum SOI regimes at part-load conditions have been identified. These are a) early injection resulting in retarded combustion and low pressure rise rate and b) late injection yielding high combustion efficiency and low hydrocarbon emission. At high-load condition, SOI right before top dead center (TDC) is most preferable and early injection should be avoided to minimize pressure rise rate. The narrow SA (90 degrees (deg) in this study) as well as wide SA were found to produce optimum performance. Subsequently, ML algorithm was used to further optimize the injector and injection parameters. As a result of this optimization study, 10.7% reduction of fuel consumption at part-load and 7.5% reduction at high-load were achieved.

Experimental investigation on single cylinder four-stroke diesel engine with copper oxide nano-additives using tomato seed oil

The purpose of this project was to do research on a single-cylinder, four-stroke diesel engine that ran on biodiesel mixtures with nano additives. The diesel–biodiesel mixes are treated with varying concentrations of nano copper oxide (CuO). The flash point, fire point, and calorific value are all properties of the material. This fuel was discovered to boost the performance and lower emissions of a single-cylinder, four-stroke diesel engine. In this work, copper oxide (CuO) is used as a nano additive in the form of copper oxide, with tomato seed oil as the base oil (biodiesel) (CuO). The copper oxide (CuO) nano additives with a diameter of 50 nm were manufactured using a variety of tomato seed oil methyl esters and then blended in varied amounts with pure diesel fuel. Throughout the study, a modified single-cylinder 4-stroke diesel engine was evaluated to determine whether it could lower its specific fuel consumption, brake thermal efficiency (BTE), air–fuel ratio (AFR), exhaust gas temperature (EGT), NOx emissions, and hydrocarbons (HC) emissions, carbon monoxide (CO). When compared to normal diesel fuel, researchers discovered lower fuel consumption, improved performance, and lower emissions of hydrocarbons (HC) and carbon monoxide (CO), but greater emissions of nitrogen oxides (NOx).

EFFECT OF MAGNETIZATION OF BIODIESEL ON ITS CHEMICAL PROPERTIES AND PERFORMANCE AND EMISSION PARAMETERS OF DIESEL ENGINE

Utilization of biodiesel results in lower emissions of hydrocarbons, carbon mono oxide, and smoke. But with the use of biodiesel as fuel emission of Oxides of nitrogen increases along with this some performance parameters also deteriorated. In the present investigation, the fact has been used that, the magnetization of fuels containing hydrocarbon changes the chemical properties as well as orientation and arrangement of molecules of fuel. In this experimental investigation density and calorific values of biodiesel have been determined. In another setup of experimentation on a single-cylinder four-stroke diesel engine, observations are taken with diesel, biodiesel blend containing 20% biodiesel (BD20), and magnetized biodiesel (BD20+MF) as fuel. Results of this investigation show that, the magnetization of biodiesel is not only helpful in increasing performance parameters like brake specific fuel consumption and brake thermal efficiency but also it helps to control the emissions of carbon mono oxide, oxides of nitrogen, hydrocarbons, and smoke. Maintaining the magnetic field just before the entry of the combustion chamber on the fuel line is a little hard, due to the regular increase in temperature of the spot where magnets are kept. It is possible that, if the strength of the magnetic field is increased then, there may be further improvement in performance and engine parameters, as in this investigation only 4000 Gauss Magnetic field has been used.

Performance and emissions of natural gas/diesel dual-fuel engine at low load conditions: Effect of natural gas split injection strategy

The combination of diesel and natural gas fuels has superior performance in terms of nitrogen oxides (NOx) and particulate matter (PM) emissions when compared to conventional diesel engine. However, this advantage does not hold at low load operating conditions as indicated thermal efficiency (ITE), carbon monoxides (CO), and unburned hydrocarbon (HC) emissions deteriorate. Most published studies tried to resolve this drawback using diesel split injection. However, the present study evaluates natural gas split injection strategy as an alternative to improve the performance and emissions of diesel/natural gas dual-fuel engines at low load conditions. The results show that natural gas split injection with proportional split injection ratio (ISR) and small dwelling timing improves NOx, CO, and HC emissions. Moreover, split injection of natural gas with proportional ISR after intake valve closing (IVC) is found to improve SFC, ITE, and power. Conversely, natural gas split injection strategy with proportional ISR after intake valve opening (IVO) yields poor engine performance. Overall, split injection of natural gas with low ISR yields the greatest engine performance at long dwelling time, whereas it worsens emissions compared to single injection of natural gas at 560°CA ATDC, which serves as the baseline condition. However, very low CO and HC emissions of natural gas split injection is achieved at low ISR and short dwelling time. Finally, this study reveals also that stratification of air/natural gas mixture due to natural gas split injection strategy can significantly improve the performance and emissions of dual-fuel diesel/natural gas engine at low load conditions.

Theoretical verification of photonic crystals sensor for biodiesel detection and sensing

Among the two past decades, the biodiesel fuels received a significant attention due to its lower hydrocarbon emissions and low sulfur diesel. However, the incomplete transesterification represents the main problem for the possibility of wider use. Thus, we present in this research a new method for detecting and measuring of methyl ester biodiesel fuel based on its optical characteristics. The proposed sensor is designed using the well-known one dimensional photonic crystals. The cornerstone of our idea is mainly based on two sides. First, the inclusion of methyl ester as a defect layer inside the one dimensional photonic crystals gives rise to the formation of a resonant peak within the photonic band gap. Second, the concentration of the converted methyl ester due to the transesterification reaction of soybean oil is closely related to its refractive index. Therefore, the sensing and detection procedure is essentially based on the dependence of the characteristics of the resonant peak on the concentration of the biodiesel fuel. The parameters that refer to the performance of our sensor such as, the sensitivity, figure of merit and the detection limit are investigated. Moreover, the effect of the defect layer thickness and the angle of incidence on the performance of our sensor is demonstrated. The numerical results show that our design could provide high sensitivity of 136 nm RIU−1 and figure of merit 2240 RIU–1. In addition to that, it could differentiate between the different biodiesel fuels despite the very limited difference between their indices of refraction.

A lab scale waste to energy conversion study for pyrolysis of plastic with and without catalyst: Engine emissions testing study

Plastics in many forms have been regarded as one of the most polluting material in the modern world. Therefore, a study has been conducted to check the effectiveness of catalyst-fly ash and zeolite on the production of biofuel from plastics as an attempt to contribute in the reduction of plastic waste pollution to the environment. A lab scale plastic pyrolysis plant has been constructed and feed particle size of 3 ± 1.5 cm2 were used as raw materials. The samples were tested in the pyrolysis plant at about 500 ± 30 °C with and without the presence of catalyst. The catalyst loading ratio of 1:10 catalyst to feed is applied. The result shows that plastic pyrolysis (bottle) without any catalysts have the highest liquid fraction yield with an average yield of 24% while those with catalyst has lower yield (16–22%). Carry bags with zeolite catalyst yield liquid fraction of 22% at a conversion rate of 47%. The inclusion of catalyst has lowered the yield but has produce oil yield of superior quality compared with the samples without catalyst. Engine characteristics study showed that blend fuel D80PO20 (80:20 diesel: plastic pyrolytic oil) have shown similar cylinder pressure during combustion with diesel. Higher brake thermal efficiency and lower brake specific energy consumption were also observed from the engine testing using the blend fuel. The blend fuel has lower hydrocarbon emissions while oxides of nitrogen reduces by 19% and 26% compared to pure diesel and PPO respectively.

Clariant's new ReforMax 330 LDP Plus catalyst increases significantly energy and production efficiency at OCI's ammonia plant

Plastics in many forms have been regarded as one of the most polluting material in the modern world. Therefore, a study has been conducted to check the effectiveness of catalyst-fly ash and zeolite on the production of biofuel from plastics as an attempt to contribute in the reduction of plastic waste pollution to the environment. A lab scale plastic pyrolysis plant has been constructed and feed particle size of 3 ± 1.5 cm2 were used as raw materials. The samples were tested in the pyrolysis plant at about 500 ± 30 °C with and without the presence of catalyst. The catalyst loading ratio of 1:10 catalyst to feed is applied. The result shows that plastic pyrolysis (bottle) without any catalysts have the highest liquid fraction yield with an average yield of 24% while those with catalyst has lower yield (16–22%). Carry bags with zeolite catalyst yield liquid fraction of 22% at a conversion rate of 47%. The inclusion of catalyst has lowered the yield but has produce oil yield of superior quality compared with the samples without catalyst. Engine characteristics study showed that blend fuel D80PO20 (80:20 diesel: plastic pyrolytic oil) have shown similar cylinder pressure during combustion with diesel. Higher brake thermal efficiency and lower brake specific energy consumption were also observed from the engine testing using the blend fuel. The blend fuel has lower hydrocarbon emissions while oxides of nitrogen reduces by 19% and 26% compared to pure diesel and PPO respectively.

Influence of Diesel Engine Intake Throttle and Late Post Injection Process on the Rise of Temperature in the Diesel Oxidation Catalyst

In order to effectively implement DPF (Diesel Particulate Filters) regeneration control, thermal management of exhaust products before and inside Diesel Oxidation Catalyst (DOC) is necessary. In the present study, the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests. The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC; in particular, with intake throttle valve opening at 20%, temperature before DOC can be increased by about 170°C with respect to the full opening. An increase in the late post injection quantity can produce a significant rise of the temperature inside DOC, however its impact on the exhaust temperature before DOC is relatively limited. As the late post injection quantity increases, Hydrocarbon (HC) emissions also grow; in the present work it is shown that with a proper injection quantity, a considerable temperature increase inside the DOC can be obtained with relatively low HC emission. More specifically, with the intake throttle valve at 30% and DOC reaching ignition temperature as the late post injection quantity is increased, the exhaust temperature after DOC can be made larger than 550°C, adequate for DPF active regeneration.

Numerical investigation of catalytic combustion in a honeycomb monolith with lean methane and air premixtures over the platinum catalyst

The stringent regulation requires low hydrocarbon emissions in combustion engines with high priority to environmental protection. For low emission technologies, catalytic combustor is an attracting option for the stable combustion process, which operates at lower temperatures than conventional engines. In this work, numerical analysis of the catalytic combustion with lean premixed methane and air is performed employing a cylindrically shaped honeycomb monolith combustor coated with the platinum catalyst. Detailed diagnostic investigations of complete catalytic combustor have been carried out using honeycomb monolith reactor in order to examine the comprehensive gaseous and catalytic surface reactions. The surface chemistry introduced by Chou on the monolith reactor consisting of numerous channels engaged along the cross-section is employed to examine the monolith temperatures and methane conversions during surface ignition. The species and surface site fractions are predicted with adsorbed species as the function of the monolith. The parameters such as the inlet temperature, fuel/air ratio, and velocity serve to govern the behavior of the catalytic combustion monolith. The reasonable requirement of catalytic combustor length for the complete combustion of the lean methane-air mixture is also determined by the numerical simulation over the platinum-coated honeycomb monolith.

The effect of diethyl ether addition on performance and emission of a reactivity controlled compression ignition engine fueled with ethanol and diesel

Reactivity controlled compression ignition has been introduced to implement controllable, clean, and high thermal efficiency without undermining the advantages of premixed combustion. However, simultaneous auto-ignition introduced by reactivity controlled combustion challenges the combustion under higher load operations. This experimental study incorporates a dual phase heat release concept with the purpose of improving the performance of reactivity controlled compression ignition engine. Different ratios of ethanol/diethyl-ether blends (from 0% to 40% diethyl ether and 70% premixed ratio) were applied to a light duty diesel engine at various combustion timings and engine loads. The diesel fuel was directly injected into the combustion chamber while ethanol/diethyl-ether blends were injected in the intake port. Engine performance and exhaust emissions were compared between the baseline operation and high blend ratios. An addition of 40% diethyl ether in the ethanol approximately resulted in 14% increase of the indicated mean effective pressure and 33% reduction in maximum pressure rise rate. The high reactivity of diethyl ether enhanced the oxidation of the hydrocarbons and resulted in lower hydrocarbon emissions. The higher volatility and better overall fuel-air mixing improved the combustion and reduced particle emission. Stable combustion was expanded at high load operating conditions due to double-stage heat release enhancement.

Intake air strategy for low HC and CO emissions in dual-fuel (CNG-diesel) premixed charge compression ignition engine

Single fueled advanced combustion technologies, such as homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI), and low temperature diesel combustion (LTC), could make it possible to escape nitrogen oxides (NOx) and particulate matter (PM) generation. However, single fueled advanced combustion technologies have several challenges to overcome in order to be commercialized, such as combustion phase control, low combustion stability, narrow operating ranges, high level of maximum pressure rise rate (MPRR), and high amounts of unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. Dual-fuel premixed charge compression ignition (DF-PCCI) combustion concepts have suggested many solutions to overcome the drawbacks of single-fueled advanced combustion technologies, such as combustion phase control, combustion stability, and limited operating range. However, high amounts of unburned HC and CO emissions are still regarded as the main hurdles of DF-PCCI combustion. In this study, the effects of global equivalence ratio (ϕglobal) and initial charge temperature, which were controlled by means of intake throttling, charge heating, and exhaust gas recirculation (EGR) strategies, were investigated to overcome the bulk quenching phenomenon under low load conditions of DF-PCCI operation in a heavy-duty (HD) single cylinder engine. The optimized intake charge strategy which used the throttle and hot-EGR, showed the possibility of simultaneous HC and CO reduction, combustion efficiency (ηc) improvement, and combustion stability enhancement while satisfying NOx and PM emissions under EU-VI regulations. The results suggest that controlling the charge air quantity and charge temperature is an effective way to mitigate the bulk quenching phenomenon under low load conditions on DF-PCCI.

Experimental and computational fluid dynamics-based numerical simulation of using natural gas in a dual-fueled diesel engine

ABSTRACTIn this paper, investigations were performed on a dual-fueled constant-speed engine. Initially, the emissions and performance of a diesel engine were investigated, and after moving to the dual-fuel engine, experimental tests were carried out under different loads (10, 25, 50, 75, and 100% of the full load) and pilot to gaseous fuel (PGF) ratios (30, 40, and 50%). The results showed that under different loads and PGF ratios, the emissions of nitrous oxides and particle materials in the dual mode were lower than those for the diesel engine, and that the difference was significant. The emission of carbon dioxide in the dual-fueled mode varied little compared to that of the diesel mode, although it was lower than that for the diesel engine. In loads lower than 75% of the full load, the emission of carbon monoxide in the diesel engine was lower than that for the dual-fueled engine. However, in full load, this result was reversed and had significant difference. The dual mode had lower hydrocarbon emission compared to that of the diesel mode in all PGF ratios and loads. A computational fluid dynamics-based numerical simulation was performed by KIVA3V, and its results showed good agreements with the experimental results under cylinder pressure.