Exhaust NOx Research Articles

Applied Intelligent Grey Wolf Optimizer (IGWO) to Improve the Performance of CI Engine Running on Emulsion Diesel Fuel Blends

Water-in-diesel (W/D) emulsion fuel is a potential alternative fuel that can simultaneously lower NOx exhaust emissions and improves combustion efficiency. Additionally, there are no additional costs or engine modifications required when using W/D emulsion fuel. The proportion of water added and engine speed is crucial factors influencing engine behavior. This study aims to examine the impact of the W/D emulsion diesel fuel on engine performance and NOx pollutant emissions using a compression ignition (CI) engine. The emulsion fuel had water content ranging from 0 to 30% with a 5% increment, and 2% surfactant was employed. The tests were performed at speeds ranging from 1000 to 3000 rpm. All W/D emulsion fuel was compared to a standard of pure diesel in all tests. A four-cylinder, four-stroke, water-cooled, direct-injection diesel engine test bed was used for the experiments. The performance and exhaust emissions of the diesel engine were measured at full load and various engine speeds using a dynamometer and an exhaust gas analyzer, respectively. The second purpose of this study is to illustrate the application of two optimizers, grey wolf optimizer (GWO) and intelligent grey wolf optimizer (IGOW), along with using multivariate polynomial regression (MPR) to identify the optimum (W/D) emulsion blend percentage and engine speed to enhance the performance, reduce fuel consumption, and reduce NOX exhaust emissions of a diesel engine operating. The engine speed and proportion of water in the fuel mixture were the independent variables (inputs), while brake power (BP), brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), and NOx were the dependent variables (outcomes). It was experimentally observed that utilizing emulsified gasoline generally enhances engine performance and decreases emissions in general. Experimentally, at 5% water content and 2000 rpm, the BSFC has a minimal value of 0.258 kJ/kW·h. Under the same conditions, the maximum BP of 11.6 kW and BTE of 32.8% were achieved. According to the IGWO process findings, adding 9% water to diesel fuel and running the engine at a speed of 1998 rpm produced the highest BP (11.2 kW) and BTE (33.3%) and the lowest BSFC (0.259 kg/kW·h) and reduced NOx by 14.3% compared with the CI engine powered by pure diesel. The accuracy of the model is high, as indicated by a correlation coefficient R2 exceeding 0.97 and a mean absolute error (MAE) less than 0.04. In terms of the optimizer, the IGWO performs better than GWO in determining the optimal water addition and engine speed. This is attributed to the IGWO has excellent exploratory capability in the early stages of searching.

Combustion and emission characterization of upgraded biomass fast pyrolysis oil in a swirl burner

Fast pyrolysis oil (FPO, also called bio-oil) is a biofuel made from thermal decomposition of renewable or waste biomass. However, the physiochemical properties of FPO have limited its widespread use in combustion applications. In this study, the impacts of FPO upgrading with multi-stage condensation, catalytic pyrolysis with ZSM-5, and ethanol blending were studied through characterization of physiochemical properties and combustion in a swirl burner. A commercially available FPO sample (COMM) and diesel were used to benchmark the upgraded FPO samples. The non-catalytic FPO (NC) sample produced with multi-stage condensation had 9.0wt% less oxygen and an HHV 2.2 MJ/kg higher than COMM. The FPO produced using ZSM-5 catalyst (CAT) had 19.0wt% less oxygen, an HHV greater by 7.4 MJ/kg, and lower viscosity than COMM. The CAT sample also had fewer low-molecular-weight compounds, showing a peak mass loss rate 70 °C higher than NC. The NC and CAT samples were also blended with 10vol% ethanol, which had minor effects on the measured physiochemical properties aside from improving volatility. Combustion was evaluated by measuring unburned hydrocarbon, CO, NOx, and particulate matter exhaust concentrations from a swirl burner as well as through flame visualization. Combustion of neat NC was stable, although compared to COMM, CO was ∼2-times higher and NOx was ∼2-times lower. In contrast, the CAT flame was unstable, resulting in the highest CO concentrations overall. Blending NC and CAT with 10vol% ethanol resulted in lower CO concentrations (NC: 88% less, CAT: 96% less) and higher NOx (NC: 2-times, CAT: 1.4-times) compared to neat FPO. Although catalytic upgrading and multi-stage condensation improved HHV, oxygen content, and viscosity, changes to these properties did not improve combustion performance. Ethanol blending emphasized the outsize role of volatility in improving furnace combustion relative to other measured physiochemical properties as reflected by the improved flame stability and exhaust composition.

Experimental Assessment of the Performance and Fine Particulate Matter Emissions of a LPG-Diesel Dual-Fuel Compression Ignition Engine

The present work is focused on the assessment of the performance and fine particulate matter emissions (PM2.5) of a turbocharged four-cylinder direct injection diesel engine operating under dual-fuel mode with Liquefied Petroleum Gas (LPG). For load levels of 30%, 60% and 100%, measurements were taken, keeping the engine speed constant at 2200, 2500 and 3200 rpm, while the engine knock detonation was detected through a non-invasive internal system. According to experimental measurements, the abnormal knock combustion occurred at full load operation with a maximum LPG energy fraction of ~60%. The brake fuel conversion efficiency increased by 2.6% with an LPG energy fraction of 10%, where a fuel saving of 11.9% was achieved with respect to the diesel-only operation. The reduction of diesel consumption was around 50% with respect to 100% diesel operation at full load operations, where the highest brake fuel conversion efficiency was achieved. The brake fuel conversion efficiency decreased as LPG addition increased for all the engine loads. Regarding emissions, PM2.5 decreased with the addition of LPG. However, HC and CO emissions increased as LPG injection was higher. NOx emissions and exhaust gas temperatures were reduced for operation with higher LPG fractions, except for full load levels at 2200 and 2500 rpm.

Storage-reduction strategy for NOx reduction from gas turbine exhaust with W–Ti-CeOx catalyst in natural gas power plants

Traditional vanadium-based selective catalytic reduction (SCR) deNOx catalyst can hardly adapt to the gas conditions (much high NO2/NOx ratio at lower temperature) of the start-up and low loading periods for a gas turbine. Therefore, a W–Ti-CeOx catalyst with NOx storage and reduction (NSR) function was developed in this work for gas turbine exhaust NOx elimination. The experimental results reveal that W–Ti-CeOx catalyst exhibits high NO2 adsorption capacity at relatively low temperature while that is quite low for V–W/TiO2. The abundant surface Ce3+ species can be mainly responsible for its high adsorption ability owing to the reaction between NO2 and Ce3+ to form nitrate/nitrite species and NO. Meanwhile, the adsorption capacity of W–Ti-CeOx can easily regenerate at medium–high temperature and NH3-SCR reaction. Furthermore, W–Ti-CeOx also shows good NH3-SCR activity, which can fulfill the deNOx process at high temperature. The addition of W and Ti into ceria can enhance the surface acidity and redox ability, thereby increasing the SCR activity. This work proposes a novel storage-reduction strategy for NOx elimination throughout the operation of gas turbines.

Characteristics of Premixed Flames of Hot and Diluted Mixtures

ABSTRACT Internal recirculation of product gases and mixing with fresh reactants, to form a hot and diluted combustible mixture, has been demonstrated to result in lower pollutant emissions. With sufficient amount of product gas recirculation, the mixture can reach above its auto-ignition temperature with low oxygen mass fractions (<4 wt%), resulting in distributed reactions instead of a flame. Some of the technologies with this feature are Moderate or Intense Low oxygen Dilution (MILD) combustion, FLameless OXidation (FLOX) and Colorless Distributed Combustion (CDC). However, if the amount of product gas recirculation is not enough and the auto ignition condition is not reached, premixed reactants of the hot and diluted mixture can be established. In this study, characteristics of such hot and diluted mixtures is studied which include the ignition delay time and the flame attributes such as laminar flame speed, S L and thermal flame thickness, . A perfectly stirred reactor (PSR) using the hot and diluted mixture as the inlet was further examined to simulate the main combustor and combustion efficiency η, and CO and NOx emissions were obtained. The investigations are performed at different product gas recirculation amounts , equivalence ratios ϕ and operating pressures P, using chemical kinetic simulations. The thermo-chemical state of the recirculated product gases was obtained using a PSR with varying residence times (τ) to simulate different “burntness” levels (smaller τ simulates lower “burntness” level). The hot and diluted mixture temperature is higher, while oxygen and fuel mole fraction are lower for higher ξ, ϕ, P, and τ. Radical species’ mole fraction is higher for higher ξ, ϕ, and lower P, τ. Lower is observed for higher ξ, ϕ, P and smaller τ. Higher S L is observed for higher ξ, ϕ and lower P. Lower is observed for higher ξ, ϕ and P. S L and are found to be higher or lower with variation in τ, depending on ξ, ϕ and P, owing to variation in temperature and radicals’ concentration. Higher η is observed for higher ξ, P, lower ϕ, τ, and higher residence time of gases (τ reac ) inside the main combustor. Lower CO is observed with increase in ξ, P and decrease in τ, while exhaust NOx increases with ϕ and mostly remains unchanged with increase in ξ, while inconsistent trends are observed with change in P and τ.

Expanding swirl combustor operability on methane-ammonia-air mixtures using a distributed fuel injection technique and inlet air preheating

The necessity to reduce greenhouse gas emissions has prompted the search for carbon-free fuel alternatives. One such carbon-free fuel source that can be used for power generation in a gas turbine-based system is ammonia. Ammonia combustion poses challenges due to reduced flame speed and reactivity, which can be alleviated by addition of methane or natural gas. However, NOx emissions continue to be an issue, which needs resolution before practical consideration of ammonia as a fuel source. One of the potential solutions that has been proposed is a two-stage, rich-lean combustion process to minimize NOx while ensuring complete reactant consumption. This work evaluates the use of two strategies to widen stability limits for swirl combustors operating on premixed methane-ammonia-air mixtures, which would facilitate the two-stage combustion approach. The first strategy involves the use of a distributed fuel injection approach utilizing a novel micro fuel injection swirler to facilitate homogeneous mixing in a highly compact manner while preventing flashback concerns. The second strategy involves use of inlet air preheating to increase flame stability and delay blow-off. The effectiveness of these strategies in expanding combustor operability limits is studied using experiments conducted in a model swirl-combustor setup designed to measure blow-off limits and evaluate exhaust NOx emissions. Complementary numerical simulations, particularly aimed at understanding NOx production pathways, are carried out using a reactor network model, wherein key inputs pertaining to recirculation volume and mass fraction are generated through detailed reacting flow simulations. The influence of the proposed strategies on NOx emissions are studied and underlying reaction pathways leading to NOx production are analyzed. Results of the study indicate that a distributed fuel injection strategy is able to significantly expand stability limits of a swirl combustor operating on methane-ammonia-air mixtures. Inlet air preheating provides additional expansion of stability limits, ≈ 7% for rich and lean blow-off, however, this is accompanied by increased NOx production, up to 14%, which is undesirable from an emissions standpoint. NOx is found to be significantly lower for rich fuel-air mixtures primarily through the effect of NHi reaction pathways responsible for NO consumption facilitated by the presence of excess NH3.

Experimental study on combustion and emission characteristics of diesel engine with high supercharged condition

The effect of diesel engine continuous strengthening on combustion and emission remains to be clarified. This study tested combustion and emission processes at different intake pressures on a single-cylinder diesel engine. The results show that the combustion of diesel engine after continuous strengthening is concentrated in diffusion and post-combustion periods, the overall heat release slows down, and the power increment decreases gradually. When the intake pressure increases to 0.25MPa, the premixed heat release peak almost disappears, while the value of diffusion combustion period increases significantly. Meanwhile, the gravity center of combustion moves backward and the cumulative heat release rate decreases. The power increases by 95% as the intake pressure increases from 0.15MPa to 0.25MPa, but only 44% as it further increases to 0.36MPa. Meanwhile, the exhaust temperature increases after high supercharging. The above effects are more prominent at high excess air coefficient and low speed. Moreover, with the decrease of excess air coefficient, the proportion of heat release in the post-combustion stage to the whole combustion increases and the power increment is limited. However, the thermal efficiency decreases approximately linearly and the fuel consumption rate increases sharply. In addition, as the excess air coefficient decreases, the exhaust temperature increases, PM increases and NOx decreases. The above effects are more pronounced at higher boost ratio.

Particulate Matter and NOx Exhaust After Treatment Systems

It is today undoubted that humans have to reduce their impact on the environment. Internal combustion engines, being the major power source in the transportation sector as well as in individual transport, play an important role in the man-made emissions. While the mobility in the world is growing, it is important to reduce the emissions that result from transportation. The diesel engine provides a high efficiency and hence it can help to reduce CO2 emissions, which are believed to be the main cause of global warming. Diesel exhaust also contains toxic gases, mainly nitrogen oxides (NOX) and soot particles. These emissions are therefore limited by the authorities in most countries.

Performance, combustion and emission characteristics of a diesel engine using composite biodiesel from waste cooking oil - Hibiscus Cannabinus oil

The energy utilization from waste is a prime requirement due to the surge in consumption, environmental emission, and pricing of automobile fuel. Biodiesel is a significant source of renewable energy, not only because of its ability to satisfy energy demand but also its ability to mitigate greenhouse gas emissions. Biodiesel was produced in this study by combining waste cooking oil (WCO) with Ambadi Seed Oil (Hibiscus Cannabinus) (AO) and WCO. The oil samples of WCO, composite oil W50A50 (50% WCO and 50% AO), and W75A25 (75% WCO and 25% AO) were converted into biodiesel employing the homogenous catalyst based transesterification technique. The critical physio-chemical properties of biodiesel samples were measured. The combustion, performance, and emissions characteristics of biodiesel samples were determined. W50A50DB20 shows maximum peak cylinder pressure and peak heat release rate of 6.37% and 13.81% higher waste cooking biodiesel blends. Brake Thermal Efficiency (BTHE) of composite biodiesel blend W50A50DB20 is 3.49% higher compared to WCDB20. BSFE of W50A50DB20 and W50A50DB30 were 4.16% and 11.51% higher compared to diesel fuel. The exhaust NOx was maximum for WCDB30 and minimum for W50A50DB20 at 100% load. The least greenhouse gas emission has resulted in W50A50DB20 among tested fuels.

Raw Jojoba Oil as a Sustainable Fuel to Diesel Engines and Comparison with Diesel Fuel

Raw Jojoba oil was used in a direct-injection diesel engine without any engine modifications and compared with both diesel fuel and 50/50 raw Jojoba/diesel. The measured parameters included the rheological properties measured in the range of shear rate from 100 to 500 1/s. Distillation data were presented for raw Jojoba oil compared to diesel. The parameters included exhaust gas analysis, block vibration, sound noise, and the combustion pressure and its rise rate. Averaged pressure-crank angle, vibration, and its frequency spectrum and sound level were presented. Data also included brake power, specific fuel consumption, and exhaust temperatures for all fuels used. For Jojoba oil, the engine did not exhibit low power output or specific fuel consumption. Exhaust temperatures, smoke opacity, and NOx emissions were lower than diesel case. Noise for Jojoba was higher than diesel case. The engine block vibration was concentrated towards the low frequency range.

Research on the Effect of the Addition of Trembesi Leaf Extract on Motorcycle Exhaust Emissions

One of the reasons for the air pollution that occurs at this time is the emission of the motorcycle exhaust. According to some sources, the trembesi leaves can absorb the level of exhaust emissions. By making extracts from trembesi leaves and added to the exhaust part of the motorcycle. Because the exhaust part is the last place of discharge of combustion waste from the combustion process that occurs on motorcycles and the result is that when the motorcycle has not been added trembesi leaf extract can produce a level of emission of Nitrogen Oxide (Nox) exhaust gases of 0.21 ppm. While the results are different when already added trembesi leaf extract can produce a level of emission of Nitrogen Oxide (NOx) exhaust gases of 0.16 ppm So it can be concluded that trembesi leaf extract can absorb or reduce the level of emission of Nitrogen Oxides (NOx), and meet the requirements of nitrogen oxide (NOx) exhaust emission levels applied in Indonesia, which is 0.17 for speeds below 1300 rpm.

The effect of fusel oil as a reductant over the multi-metallic catalyst for selective catalytic reduction of NOx in diesel exhaust at low-temperature conditions

In this paper, the NOx conversion efficiency of Mo-Cu-Ag/TiO2/Cordierite catalyst at low temperatures was investigated by using fusel oil as a reductant. The properties of Mo-Cu-Ag/TiO2/Cordierite catalyst prepared by the impregnation method were analyzed by Brunauer-Emmett-Teller, scanning electron microscopy with energy dispersive spectroscopy, Fourier-transform infrared spectroscopy analyses, and X-ray diffraction. The SCR performance tests were performed under real diesel exhaust gas conditions in a temperature range from 200 °C to 290 °C with a rise of 10 °C, five different engine loads, and three different space velocities. The minimum and maximum NOx conversion rates were determined as 78,99% at 5 kW and 85.94% at 1 kW engine load, respectively.

Artificial neural network prediction of performance and emissions of a diesel engine fueled with palm biodiesel

Increasing of energy consumption, depletion of petroleum fuels and harmful emissions have triggered the interest to find substitute fuels for diesel engines. Palm ethyl ester was synthesized from palm oil through transesterification process. The physicochemical properties of palm biodiesel have been measured and confirmed in accordance with ASTM standards. The aim of the paper is to show the effect of different diesel-palm biodiesel blends on performance, combustion and emissions in diesel engine at engine load variation. Artificial Neural Network was used for the prediction of engine performance, exhaust emission and combustion characteristics parameters. Palm ethyl ester and diesel oil were blended in 5, 10, 15 and 20 by volume percentage. The maximum decreases in thermal efficiency, fuel–air equivalence ratio for B20 were 1.5, 3.5, 6 and 8% but the maximum increases in BSFC, exhaust gas temperature and NOx emission for B20 at full load about diesel fuel were 9, 8 and 10%, respectively. The highest decreases in CO, HC and smoke emissions of B20 about diesel oil at full load were 2, 35 and 18.5% at full load, respectively. Biodiesel blend B20 achieved the maximum declines in peak HRR, cylinder temperature and combustion duration about diesel fuel. The results of ANN were compared with experimental results and showed that ANN is effective modeling method with high accuracy. Palm biodiesel blends up to 20% showed the highest enhancements in engine performance, combustion and emission reductions compared to diesel fuel.

Investigation of the effect of JP-8 fuel and biodiesel fuel mixture on engine performance and emissions by experimental and statistical methods

In this study, the effects of JP-8 military aviation fuel and biodiesel sunflower oil on the performance and emissions of the internal combustion engine were investigated by creating a mixture of fuel in different concentrations. Experimental and statistical methods were used in the study process. All of the experiments were carried out on an experimental setup with a single-cylinder compression-ignition engine at 7.5, 12.5 and 17.5 Nm engine load conditions. A total of 5 different fuels were used, including pure JP-8 fuel, 3 different blended fuels and pure biodiesel fuel. The design of the Response Surface Method, which is used as a statistical method, was carried out with Central Composite Design in the Design Exper 11 program environment. After the created design, 13 different experiments were carried out. With the tests performed, the values of IMEP, BSFC, COVimep, ignition delay, equivalence ratio, exhaust gas temperature, CO, and NOx emission response parameters were determined. Quadratic models were created by performing variance analysis for the response parameters obtained. After the optimization, it was concluded that the engine load should be 14.49 Nm and the JP-8 fuel biodiesel ratio should be 2.47%. In case the internal combustion engine is operated with optimum input parameters, IMEP value is 3.71 bar, BSFC value is 193.46 g/kWh, COVimep value is 5.99 bar, CO value is 724 ppm and NOx value is 168.62 ppm.

Emission and Performance Evaluation of a Diesel Engine Using Addition of Ethanol to Diesel/Biodiesel Fuel Blend

Many countries have adopted the addition of biodiesel to diesel as a way of inserting renewable content into mineral fuel and making a contribution to the environment. The addition of ethanol to the diesel/biodiesel blend to increase the renewable content of the added fuel blend and reduce the percentage of biodiesel could be a strategysince the demand for biodiesel production is high, and this fuel has a high production cost when compared to ethanol. Thus, this study evaluated the performance and the content of NOx, CO and CO2 exhaust gases from a diesel engine fueled with blends of diesel/biodiesel/ethanol: pure B7, B7E3 (B7 with 3% ethanol) and B7E10 (B7 with 10% ethanol). Emissions of fuel blends were evaluated using the engine speed variation and tested at a speed of 1500 rpm under constant load (185 Nm). Assays were performed at engine speeds of 1000, 1100, 1250, 1500 and 1750 rpm and with loads of 10, 25, 50, 75 and 100% of the maximum torque. Through the performance curves, the specific consumption and thermal efficiency were evaluated. The increase in speed and ethanol content in the diesel/biodiesel mixture increased approximately 5 to 7 and 1.4 times, respectively, in terms of the emission of exhaust gases. There was a 6% decrease in the maximum torque and power available at each speed with increasing ethanol content in the blend. However, in a vehicular application, this decrease would be perceived only at some points of the part-load regime, causing considerable reductions in thermal efficiency.

Pengujian Eksperimental Perbandingan Konsumsi Bahan Bakar dan Emisi Gas Buang Dengan Beberapa Jenis Bahan Bakar Pada Sepeda Motor

Air pollution is caused by the activities of motorized vehicles that emit exhaust gas emissions, including CO, CO2, HC, NOX, SOX, and particulates. The purpose of this study was to determine how the effect of fuel variations on the time of fuel consumption and exhaust emissions on motorcycles and to find out how the composition of mixing premium fuel with ethanol affects the time of fuel consumption and exhaust emissions. This study uses 4 types of fuel, namely premium, pertalite, E-5, and E-10 and tested using 3 variations of throttle openings. From the test results, it is found that the most fuel consumption is found in the wide throttle opening on premium fuel = 0.77 L/h. For the results of the lowest CO and HC exhaust emissions found in the wide throttle opening on the E-10 fuel where the emission value of CO = 1.98% and HC = 1425 ppm. So it can be concluded that in comparison with the time of fuel consumption, the higher the throttle opening, the faster the fuel consumption will be and for exhaust gas emissions, the higher the throttle opening, the lower the CO and HC emission values. Mixing premium fuel with ethanol can make the fuel consumption time slower than pure premium and can also reduce the content of CO and HC exhaust emissions.Key words: Fuel, Exhaust emissions, Fuel consumption

High-efficiency absorption of low NOX concentration in metallurgical flue gas using a three dimensional printed large-flow microstructured reactor

In the process of nitric acid dissolving precious metals, a large amount of NOx exhaust gas will be produced. This research aims at the development of a new method for the removal of low-concentration nitrogen oxides from metallurgical flue gas. In this process, a printed three-dimensional large-flow microstructure reactor and urea solution are used for the removal of NOx, which facilitates the greater efficiency of denitrification(≥94%). Urea plays an important role in the redox of NO 2 , such as NO 2 is reduced to N 2 in solution. Both the gas and the liquid phase simultaneously react in the microchannels of the microfluidic reactor. The channels allow the proper mixing of urea and NaClO 2 during the flow which efficiently removes NO x at low concentrations. The optimum condition for high denitration efficiency is outlined: the urea solution with 3%,temperature of the mixed solution is 293.15 K, gas–liquid flow mass ratio is 1:1, pH value (8.0–10.0), C NaClO2 = 0.02 mol/L. This work successfully describes the use of a microfluidic reactor to enhance and maintain the denitration efficiency. This work describes how to successfully enhance and maintain the denitration efficiency while using a printed three-dimensional large-flow microstructure reactor.

Experimental evaluation of the impacts of diesel-nanoparticles-waste tire pyrolysis oil ternary blends on the combustion, performance, and emission characteristics of a diesel engine

In the present research, pyrolytic oil is obtained from the waste tire chips, and then acid washing process, clay and calcium oxide process, distillation process, and oxidative sulfur removal processes are used to improve its properties. Then it is blended into conventional diesel fuel with/without Al2O3 nanoparticles, and the performance, combustion, and emission characteristics of a single-cylinder, air cooled, and naturally aspired diesel engine are discussed in this study. Tests were performed at varying engine loads from 3 to 12 Nm with the gaps of 3 Nm under a constant engine speed of 2400 rpm. In this study, three types of fuels were tested, namely D100 (100% diesel fuel), P10 (90% diesel fuel and 10% pyrolytic oil), and P10 + 1 g Al2O3 (obtained by adding 1 g of Al2O3 nanoparticles to P10 fuel). The addition of Al2O3 nanoparticles increased the brake thermal efficiency while reducing the maximum in-cylinder pressure, heat release rate, specific fuel consumption, exhaust gas temperature, hydrocarbon emissions, NOx emissions, and CO emissions compared to other test fuels. Namely, with the addition of Al2O3 nanoparticles, BTE was improved by 4.51% and 1.59% compared to P10 and pure diesel fuel, respectively. According to this, the BSFC value increased by 4.29% for P10 test fuel and then is reduced by 2% for P10 + 1 g Al2O3 test fuel as compared with conventional diesel fuel. Compared to diesel fuel, the CO, NOx, and HC emission values deteriorated by 17.5%, 5.69%, and 18.6%, respectively, with the addition of pyrolysis oil, and these deteriorated properties were improved by 10%, 6.82%, and 13.95%, respectively, with the addition of Al2O3 nanoparticles. In the light of this study, it was observed that while waste tire pyrolysis oil worsened engine performance, emission, and combustion characteristics, these deteriorations could be improved with nano Al2O3 supplementation.

A study on effect of engine operating parameters on NOx emissions and exhaust temperatures of a heavy-duty diesel engine during idling

Though NOx emissions from on-road heavy duty vehicles (HDVs) have reduced drastically over the past three decades, upcoming North American regulations may call for further reductions. Lowering NOx emissions below current levels is challenging, especially at lower operating loads such as idling and/or colder climates when the exhaust gas temperature is insufficient for high NOx conversion in the HDV’s exhaust after treatment (EAT) system. This paper investigates the impact of various engine operating parameters on the three-way trade-off between NOx emissions, exhaust temperature, and fuel consumption using a single-cylinder, heavy-duty diesel engine outfitted with a conventional EAT system and diesel exhaust fluid (DEF) injection. The engine parameters investigated include exhaust gas recirculation (EGR) ratio, intake pressure, intake temperature, injection pressure, multiple injections, and engine fluid temperatures. In order to simulate cold climate operation, the baseline intake air, coolant, and lubricating oil temperatures are maintained at 10°C, 40°C, and 50°C, respectively. Results show that using a moderate level of EGR has the dual benefit of reducing the engine-out NOx and increasing the intake charge temperature. Increasing the intake or injection pressure does not result in significant benefit in improving the three-way trade-off. However, using double injection with the second injection at the start of the expansion stroke can help reduce NOx emissions and increase exhaust temperature with marginal impact on fuel efficiency. Based on the parametric study, three particular engine operating conditions are chosen for further investigation with the EAT online. At an identical DEF dosing rate, the rates of NOx reduction in the SCR are similar for the three conditions (∼96%), and the lowest tail-pipe NOx observed for this study is 0.032 g/kWh.

Prediction of dispersion behavior of typical exhaust pollutants from hydraulic support transporters based on numerical simulation.

We investigated the impact of exhaust emissions from hydraulic support transporters on the air quality in roadways in mines. The dispersion distribution of diesel exhaust pollutants emitted by hydraulic support transporters was simulated with a dynamic mesh and computational fluid dynamics (CFD) simulations. More specifically, the dispersion and distribution of the main exhaust pollutants CO, HC, and NOx emitted by vehicles under the influence of the roadway wind flow were simulated with CFD simulations; in addition, the dispersion characteristics of exhaust pollutants from hydraulic support transporters during multiple driving phases in an alleyway (from transporting material, being unloaded at idle speed, to driving off without load) were predicted. The simulation results show that exhaust pollutants emitted by moving hydraulic support transporters can pollute the air in roadways and negatively affect the performance of gas monitoring devices in the roadway. Therefore, coal mining companies should optimize the ventilation design scheme to improve the air quality in roadways: they should increase the ventilation volume to dilute the emitted pollutants; in addition, the positions of underground gas monitoring devices should be adjusted to prevent interference from exhaust pollutants emitted by vehicles. This paper provides the theoretical basis and results of a preliminary investigation of the dispersion and transportation characteristics of exhaust pollutants emitted by vehicles in roadways. The results in this paper can serve as guidance for reducing the risk of occupational diseases.