Increase In Nitrogen Oxides Research Articles

Prenatal exposure to near-roadway air pollution and autism spectrum disorders in children

BACKGROUND AND AIM: Previous studies have reported associations between {in-utero} exposure to regional air pollution and autism spectrum disorders (ASD). {In-utero} nitrogen oxide (NOx) exposure has been linked to adverse neurodevelopment in animals and cardiovascular conditions in humans, but few studies have investigated pregnancy exposure to near-roadway air pollution (NRAP) and ASD risk. METHODS: This retrospective birth cohort included 311,617 mother-child pairs of singletons born between 2001-2014 at Kaiser Permanente Southern California (KPSC) hospitals. Maternal and child data were extracted from KPSC electronic medical records. Children were followed until: clinical diagnosis of ASD, non-KPSC membership, death, or December 31, 2019, whichever came first. Exposure to the complex NRAP mixture during pregnancy was estimated by monthly California line-source dispersion models (CALINE4) for both near-roadway (freeway; non-freeway) and total NOx, using maternal addresses during pregnancy. Cox proportional-hazard models were used to estimate hazard ratios (HR) of ASD associated with NRAP during pregnancy, adjusted for covariates. Nonfreeway NRAP was analyzed using quintile distribution due to nonlinear associations with ASD. RESULTS:A total of 6,291 children (5,114 boys, 1,177 girls) were diagnosed with ASD. Prenatal exposure to total NRAP was associated with ASD diagnosis [HR (95% CI): 1.03 (1.00,1.06) per 10 ppb increase in NOx]. Nonfreeway NRAP was associated with ASD diagnosis; however, freeway NRAP was not. The HR (95% CI) comparing the highest quintile of nonfreeway NRAP exposure (3.8 ppb NOx) to the lowest quintile (0.89 ppb) or to the lower 4 quintiles (≤3.8 ppb) were 1.20 (1.08, 1.33) and 1.20 (1.13, 1.27) respectively. The HR (95% CI) associated with high nonfreeway NOx (3.8 vs ≤3.8 ppb) were significant in boys [1.20 (1.10, 1.26)] and girls [1.23 (1.06,1.39)], and robust to adjustment for PM2.5. CONCLUSIONS:Prenatal exposure to near-roadway air pollution, particularly from nonfreeway sources, may be associated with ASD risk in boys and girls KEYWORDS: oxides of nitrogen, neurodevelopmental, children's environmental health

Effect of Injection System Parameters on Performance and Emission Characteristics of a Small Single Cylinder Diesel Engine

Limited fossil fuel reservoir capacity and pollution caused by them is the big problem in front of researchers. In the present paper, an attempt was made to find a solution to the same. The conventional fuel injection system was retrofitted with a simple version of the common rail direct injection system for the small diesel engine. Further, the effect of injection system parameters was observed on the performance and emission characteristics of the retrofitted common rail direct injection diesel engine. The parameters such as injection pressure, the start of pilot injection timing, the start of main injection timing and quantity of percentage fuel injection during the pilot and main injection period were considered for experimental investigation. It was observed that all the evaluated parameters were found vital for improving the engine’s performance and emission characteristics. The retrofitted common rail direct injection system shows an average 7% rise in brake thermal efficiency with economic, specific fuel consumption. At the same time, much more reduction in hydrocarbon, carbon monoxide and smoke opacity with a penalty of a slight increase in nitrogen oxides.

The effects of n-butanol/gasoline blends and 2.5% n-butanol/gasoline blend with 9% water injection into the intake air on the SIE engine performance and exhaust emissions

The aim of this paper was to investigate the effects of n-butanol/gasoline blends (nBGBs), 2.5% n-butanol/gasoline blend with 9% water injection into the intake air on the engine performance, fuel cost and exhaust emissions in an automobile spark-ignition engine. Experiments have been performed for three different nBGBs, nB2.5 (nB2.5 contains 2.5% n-butanol and 97.5% gasoline in volume basis), nB5 and nB7.5 for five different loads at 3000 and 5000 rpms. The test results showed that nBGBs generally decrease brake specific fuel consumption (bsfc) at all of the selected operating conditions. The maximum reductions of bsfc at 3000 and 5000 rpms have been attained at the levels of 7.22% and 9.99% for nB2.5, respectively. nBGBs decrease carbon monoxide (CO) and total hydrocarbon (THC) emissions at the selected operating conditions. However, nBGBs increase nitrogen oxides (NOx) at 3000 rpm. At 5000 rpm, nB2.5 and nB5 reduce NOx but nB7.5 increases NOx. The NOx could not be reduced as much as desired by applying nBGBs. For this reason, 9% water introduction into the intake air with nB2.5 (nB2.5-WI9) have been applied to decrease NOx. The test results showed that nB2.5-WI9 and nB2.5 decrease NOx approximately 58% and 9%, respectively at 5000 rpm. nB2.5-WI9 reduces CO more than nB2.5 at two engine speeds. However, nB2.5-WI9 increases THC and bsfc more than nB2.5. Total fuel cost for nB2.5 and nB2.5-WI9 become higher than neat gasoline. However, nB2.5-WI9 shows higher fuel cost as compared to nB2.5.

Extraction of bioethanol from waste pomegranate fruits as a potential feedstock and its blending effects on a performance of a single cylinder SI engine

Fossil fuel depletion and strict government regulations have necessitated the finding of alternatives to conventional fuel sources. The growing population and better transport are increasing the need for energy every day. The pollution and disposal of agriculture and food waste are still serious problems to be tackled. Bioethanol has proved an alternative to S.I. engine diesel and gasoline. 10% ethanol blending is widely used by passenger cars worldwide and countries such as India have announced the implementation of a 20% ethanol blending in petrol. As a result, demand for ethanol is growing and there is inadequate bioethanol supply to meet demand. This paper portrays the extraction of ethanol from the waste pomegranate fruits and effect of its different blends on the spark ignited engine performance. Ethanol was extracted using fermentation and steam distillation processes from waste pomegranate fruit. Four blends were prepared on volumetric basis and tested for various performance and emission parameters at a constant compression ratio of 10:1 and wide-open throttle at various engine speeds. Indicated power, volumetric efficiency, and mechanical efficiency were improved by ethanol enrichment. Enrichments of ethanol decrease emissions of HC, CO and CO2, however increase nitrogen oxide emissions. The engine performance was found optimal for WPFE15 among all fuel blend studied. This study recommends the use of waste pomegranate fruits as a source for production of second-generation ethanol if after treatments be performed to reduce NOx emissions. This study proposes the use of waste pomegranate fruits for second-generation ethanol processing, if NOx pollution after treatment is carried out.

Experimental investigation of a heavy-duty natural gas engine performance operated at stoichiometric and lean operations

There is a need for decarbonization in power generation and transportation. Natural gas can replace conventional petroleum fuels due to its low carbon-to-hydrogen ratio, especially in existing diesel engines. This paper was based on the hypothesis that “ideal” natural gas engines would operate both stoichiometric and lean, as needed. Therefore, the need to identify the effect of leaning the mixture on several parameters not usually shown in the literature. This paper compared the performance and emissions of a heavy-duty diesel engine converted to natural gas spark ignition operation under stoichiometric (equivalence ratio, ϕ = 1.0) and lean (ϕ = 0.8) operation. The original cylinder head and piston were maintained, and no exhaust gas recirculation was used. The results showed that lean operation decreased peak cylinder pressure and maximum pressure rise rate by 10–15% and 1 bar/°CA, respectively, and increased the volumetric efficiency from ~72% to ~74%. While it also increased the ignition lag, which translated in up to 5°CA delay in the location of peak pressure and crank angle associated with 50% of energy release at the same spark timing and a ~ 5°CA advance in the location of maximum indicated mean effective pressure, it had a negligible effect on the combustion duration due to distinguishing characteristics of gas and flame motion in the bowl-in-piston chamber. Lean operation increased unburned hydrocarbon and nitrogen oxides emissions by up to 15% and 300%, respectively, and carbon monoxide emissions were ~ 20× lower. Lean operation improved indicated thermal efficiency by two percentage points due to a 15% decrease in the heat losses but decreased the exhaust temperature by ~ 50 °C, which would affect the aftertreatment performance. Stoichiometric operation reduced the combustion fluctuations. However, the increased turbulence inside the “fast-burn” bowl-in-piston chamber compensated for the lower natural gas flame speed, with a variation of the indicated mean effective pressure below 2.5% even at ϕ = 0.8. Finally, important differences were observed compared to a traditional spark ignition engine. For example, diesel engine conversation increased nitrogen oxides emissions under lean burn but lowered unburned hydrocarbon and carbon oxide emissions when retarding spark timing from the optimum value. These findings suggest that more studies are needed to better understand the optimization of dedicated natural gas engines converted from diesel, under both lean and stoichiometric operations.

Environment‐friendly fuel Cymbopogon flexuosus: Analysis of fuel properties, performance, and emission parameters of a Direct Injection Compression Ignition research engine

AbstractThe novelty of this study discusses on the influence of neat lemongrass oil (LGO) on fuel analysis, performance and emission analysis, naturally aspirated diesel engine. The critical parameters include iodine value, flash point, kinematic viscosity, saponification and cetane numbers, calorific value, Fourier transform infrared spectroscopy (FT‐IR), and gas chromatography–mass spectroscopy (GC‐MS) studies were investigated. The oxygenated elements, such as naphthalene, caryophyllene, pentadecanoic acid, dihydropyridine, d‐limonene are observed using GC‐MS analysis. The higher hydrocarbon (HC) chain length indicates a rise in energy density and boiling point with a reduction of volatility. Using FT‐IR analysis, C–H stretching vibrations are found at a frequency of 1672 cm−1. The C≐C stretching vibrations at 1740 cm−1 reveals the availability of the alkenes/fingerprint phase. Experiments were conducted at four different volumetric blend ratios of LGO‐diesel blends at typical injection parameters under different loading conditions. Brake thermal efficiency (BTE) decreased for all the test combinations of LGO than diesel. BTE is observed as 30.79% at diesel, 30.06% at LGO25, 28.71% at LGO50, 27.77% at LGO75%, and 27.23% at LGO100. The cylinder pressure and heat release rate increased proportionately with the LGO fuel mixture. Carbon monoxide, HC, and smoke emissions are reduced by LGO mixtures than diesel at the full load of the engine. It was noted that greater blends of LGO and diesel resulted in increased nitrogen oxide (NOx) emissions and engine tribological characteristics. The NOx is increased by 21.2% at LGO25, 24.3% at LGO50, 26.5% at LGO75 and 30.8% at LGO100 when compared with diesel. Without any chemical processing, Cymbopogon flexuosus oil can be blended directly with diesel fuel.

Effect of multi-walled carbon nanotubes on pre-vaporized palm oil biodiesel/air premixed flames

In regard to the current state of global energy, the high demand for traditional fossil fuels and their negative environmental impact have led to an increase of interest in the development of renewable clean fuels. Recently, nano-additives such as carbon nanotubes (CNTs) have been considered as a potential additive to increase fuel combustion performance. Thus, we experimentally studied the combustion characteristics of multi-walled carbon nanotubes (MWCNTs) blended palm-oil biodiesel/air mixtures at a wide range of equivalence ratios, 0.7–1.6. Experiments were conducted at atmospheric pressure and a temperature of 550 K to ensure full vaporization of the liquid biodiesel fuel. Concentrations of the MWCNTs in the mixture were varied from 25 to 200 ppm for two different groups of nanotubes having outer diameter ranges of 10–20 nm and 30–50 nm. The results showed that both laminar burning velocity and blowoff velocity were increased with the additions of MWCNTs. Besides, the flammability limits of MWCNTs blended biodiesel/air premixed flames were also extended at both fuel-lean and fuel-rich conditions. It was also observed that the MWCNTs of 10–20 nm experienced more noticeable improvements in the combustion characteristics compared to the MWCNTs of 30–50 nm. After reaching the highest enhancement, a further increase in the concentration of MWCNTs generally caused less improvement in the laminar burning velocities of the premixed flames. Besides, the addition of MWCNTs increased nitrogen oxides and decreased carbon monoxide concentrations in the combustion products.

Impact of regional Northern Hemisphere mid-latitude anthropogenic sulfur dioxide emissions on local and remote tropospheric oxidants

Abstract. The unintended consequences of reductions in regional anthropogenic sulfur dioxide (SO2) emissions implemented to protect human health are poorly understood. SO2 decreases began in the 1970s in the US and Europe and are expected to continue into the future, while recent emissions decreases in China are also projected to continue. In addition to the well-documented climate effects (warming) from reducing aerosols, tropospheric oxidation is impacted via aerosol modification of photolysis rates and radical sinks. Impacts on the hydroxyl radical and other trace constituents directly affect climate and air quality metrics such as surface ozone levels. We use the Geophysical Fluid Dynamics Laboratory Atmospheric Model version 3 nudged towards National Centers for Environmental Prediction (NCEP) reanalysis wind velocities to estimate the impact of SO2 emissions from the US, Europe, and China by differencing a control simulation with an otherwise identical simulation in which 2015 anthropogenic SO2 emissions are set to zero over one of the regions. Springtime sulfate aerosol changes occur both locally to the emission region and also throughout the Northern Hemispheric troposphere, including remote oceanic regions and the Arctic. Hydroperoxy (HO2) radicals are directly removed via heterogeneous chemistry on aerosol surfaces, including sulfate, in the model, and we find that sulfate aerosol produced by SO2 emissions from the three individual northern mid-latitude regions strongly reduces both HO2 and hydroxyl (OH) by up to 10 % year-round throughout most of the troposphere north of 30∘ N latitude. Regional SO2 emissions significantly increase nitrogen oxides (NOx) by about 5 %–8 % throughout most of the free troposphere in the Northern Hemisphere by increasing the NOx lifetime as the heterogeneous sink of HO2 on sulfate aerosol declines. Despite the NOx increases, tropospheric ozone decreases at northern mid-latitudes by 1 %–4 % zonally averaged and by up to 5 ppbv in summertime surface air over China, where the decreases in HO2 and OH suppress O3 production. Since 2015 anthropogenic SO2 emissions in China exceed those in the US or Europe, the oxidative response is greatest for the China perturbation simulation. Chemical effects of aerosols on oxidation (reactive uptake) dominate over radiative effects (photolysis rates), the latter of which are only statistically significant locally for the large perturbation over China. We find that the SO2 emissions decrease in China, which has yet to be fully realized, will have the largest impact on oxidants and related species in the Northern Hemisphere free troposphere compared to future decreases in Europe or the US. Our results bolster previous calls for a multipollutant strategy for air pollution mitigation to avoid the unintended consequence of aerosol removal leading to surface ozone increases that offset or mask surface ozone gains achieved by regulation of other pollutants, especially in countries where current usage of high-sulfur emitting fuels may be phased out in the future.

Effect of rubber seed oil biodiesel on engine performance and emission analysis

Application of biodiesel prepared from rubber seed oil using calcined eggshells in a diesel engine is the main novelty of present work. In this study, the performance and emission analysis of biodiesel prepared at optimum process conditions of 12:1 methanol: oil molar ratio, 4 (wt. %) of catalyst concentration and 3 h of reaction time is tested in a diesel engine for three different blends namely B10, B20 and B30 respectively. A gradual increase in brake thermal efficiency and a slight decrease in brake specific fuel consumption with increase in brake mean effective pressure for all blends was observed. The minimum brake specific fuel consumption is observed as 0.3895 (kg/kWh) for B10 blend which is almost near to the value obtained from conventional diesel 0.38 (kg/kWh). The maximum brake thermal efficiency was observed as 73.26 (%) for B10 blend when compared with conventional diesel of value 75.8 (%). A decrease in carbon monoxide (0.0275% for B30 blend) as well as hydrocarbons (36 ppm for B10 blend) and a gradual increase in nitrogen oxide (275 ppm for B30 blend), as well as carbon-di-oxide (1.9% for B30 blend) were also observed with increase in brake mean effective pressure of every blend. From the observed results it is justified that the synthesized biodiesel (prepared from rubber seed oil) is a feasible substitute to conventional diesel.

Potential Improvement in PM-NOX Trade-Off in a Compression Ignition Engine by n-Octanol Addition and Injection Pressure

n-Octanol, as an oxygenated fuel, is considered as one of the most promising alternative fuels, owing to advantages such as its low hygroscopic nature, high cetane number, and high energy content. However, the introduction of n-octanol leads to a higher viscosity and latent heat of evaporation (LHOE), affecting the combustion and emission performances of compression ignition (CI) engines. This study sheds light on the effect of injection pressures (IPs, ranging from 60 to 160 MPa) on the combustion and emission performances of a turbocharged CI engine, in conjunction with n-octanol/diesel blends. According to the proportion of oxygen content, the test fuels contain pure diesel (N0), N2.5 (2.5% oxygen content in the blending fuels), and N5 (5% oxygen content in the blending fuels). The results indicate that the blending fuels have little influence on the in-cylinder pressure, ignition delay (ID), and CA50, but they improve the brake thermal efficiency (BTE). In terms of emissions, with the use of blending fuels, the levels of carbon monoxide (CO), soot, and nitrogen oxides (NOX) decrease, whereas emissions of hydrocarbons (HC) slightly increase. With increasing IP, the ID, brake specific fuel consumption (BSFC), HC, CO, and soot decrease significantly, and the BTE and NOX increase. In addition, the combination of n-octanol and IP improves the trade-off between NOX and soot and reduces the CO emissions.

Enhancement of idling characteristics using multi-objective approach in light-duty diesel Vehicle fuelled with orange peel biofuel

Along with an increasing demand for an alternate source of fossil fuel, rapid urbanization has increased the motor vehicle pollutant spews in a metropolis, especially in traffic congestion or cold start condition. In reference to these situations; this research is aimed at utilizing orange peel oil (OPO) as blend fuel to mineral diesel in light-duty diesel engine and asses the output characteristics for optimizing engine fuel map under idling condition. A four-factor central composite design (CCD) approach-based response surface methodology (RSM) analysis is applied to statistically relate the effect of important input variables on key engine characteristics to achieve minimum emissions without a major compromise on the power output. From the desirability report, for orange Peel Oil (20%) blended with diesel fuel (80%) (OPO20) fuel, the optimum pilot injection timing is 210 before top dead centre (bTDC), pilot mass of 24% and apt fuel injection pressure is 500 bar while maintaining 1100 rpm as idle engine speed. While tuning the OPO20 operated engine fuel map under this optimum operating condition, a notable reduction of 34% in carbon monoxide and 36.84% reduction in smoke is observed in comparison to diesel. However, the increased mean gas temperature in-turn translated into 37.65% increase in oxides of nitrogen. As a trade-off to the reduced emissions, a 15.47% decrease in the brake thermal efficiency is observed while the specific fuel consumption also increased by 29.98% in comparison to diesel operation.

Wastes to energy: Improving the poor properties of waste tire pyrolysis oil with waste cooking oil methyl ester and waste fusel alcohol – A detailed assessment on the combustion, emission, and performance characteristics of a CI engine

The core objective of this study is to pull back the worsened combustion, emission, and performance characteristics of a CI engine fuelled with waste tire pyrolysis oil - diesel fuel blends. Four fuels are tested in the experiments. These are (1) 100% diesel fuel, (2) 20% waste tire pyrolysis oil + 80% diesel fuel, (3) 10% pyrolysis oil and 80% diesel fuel containing 10% waste biodiesel, and finally, (4) 10% waste tire pyrolysis oil and 80% diesel fuel containing 10% waste fusel oil. The tests are performed at a constant engine speed of 2400 rpm, and varying engine loads from 3 to 12 Nm with intervals of 3 Nm. In the results, it is noticed that using of waste tire pyrolysis oil - diesel fuel blend is reducing the brake thermal efficiency down to 9.13% for waste tire pyrolysis oil - diesel fuel blends, however, this reduction is being pulled back by 7.51%, and 3.82% with the addition of waste biodiesel, and fusel oil, respectively as compared to that of diesel fuel. On the other hand, waste tire pyrolysis oil - diesel fuel blend increased the brake specific fuel consumption by 21.78%, however, this increase is being pulled back by 8.89%, and 12.57% for waste biodiesel, and fusel oil, respectively. The increase in carbon monoxide for waste tire pyrolysis oil-diesel fuel is 7.09% in comparison with that of diesel fuel. However, with the addition of biofuels, carbon monoxide is being dropped by 7.69% for waste biodiesel, and 19.23% for fusel oil due to the high oxygen contents of waste biofuels. Moreover, waste tire pyrolysis oil-diesel fuel blend is increasing nitrogen oxide by 7.09%, but this increase by 4.64% with the addition of waste biodiesel. On the other hand, the addition of fusel oil is converting the increasing trend of nitrogen oxide into a reduction of 3.09% owing to fusel oil’s water content. As a consequence, this research is proving that the waste biofuels are able to improve poor combustion, emission, and performance characteristics of binary waste tire pyrolysis oil – diesel blend with the doping of waste biofuels, and suggesting ternary blends rather than waste tire pyrolysis oil alone for diesel engines. Moreover, it is noticed that burning waste products is a very effective tool for both waste management and alternate to fossil fuels.

Important contributions of non-fossil fuel nitrogen oxides emissions

Since the industrial revolution, it has been assumed that fossil-fuel combustions dominate increasing nitrogen oxide (NOx) emissions. However, it remains uncertain to the actual contribution of the non-fossil fuel NOx to total NOx emissions. Natural N isotopes of NO3− in precipitation (δ15Nw-NO3−) have been widely employed for tracing atmospheric NOx sources. Here, we compiled global δ15Nw-NO3− observations to evaluate the relative importance of fossil and non-fossil fuel NOx emissions. We found that regional differences in human activities directly influenced spatial-temporal patterns of δ15Nw-NO3− variations. Further, isotope mass-balance and bottom-up calculations suggest that the non-fossil fuel NOx accounts for 55 ± 7% of total NOx emissions, reaching up to 21.6 ± 16.6Mt yr−1 in East Asia, 7.4 ± 5.5Mt yr−1 in Europe, and 21.8 ± 18.5Mt yr−1 in North America, respectively. These results reveal the importance of non-fossil fuel NOx emissions and provide direct evidence for making strategies on mitigating atmospheric NOx pollution.

Use of bio additives in diesel engine fuels

The use of fuel additives in various engines improves their performance. In particular, biodiesel is considered to be a good additive in diesel fuel. It is one of the alternative fuels used in diesel engines. The use of this type of fuel is also of strategic importance in the development of the economy of the countries. The main problem is to find the optimal ratio between biofuel and conventional diesel fuel in the mixtures injected into the engine cylinders. One of the advantages of biofuel is that it significantly reduces the amount of harmful emissions from engines - especially CO and HC. Along with this advantage, there is an increase in nitrogen oxides, which are released during the combustion of the mixture of the bio-additive and ordinary diesel fuel. Many of the challenges facing the use of biofuels are related to the reduction of NOx. Exhaust Gas Recirculation (EGR) is also used to reduce them.

Aqueous phase recycling in catalytic hydrothermal liquefaction for algal biomass and the effect on elemental accumulation and energy efficiency

Abstract Generating green-based liquid fuels using hydrothermal liquefaction is a promising method for fossil fuel replacement. This study investigates the impact of recycling the aqueous phase in hydrothermal liquefaction processing on fuel yield, quality and energy efficiency using algae as the feedstock. Recycling the aqueous phase in algal hydrothermal liquefaction increased biocrude production yield by 18.9% at 350 °C, although a 12.2% increase in the biocrude nitrogen content was observed. In the second recycling, the nitrogen content increased to 17.6%, which is not environmentally favourable for direct usage in diesel engines due to the possible increase in Nitrogen Oxides (NOx) emissions. Recycling the aqueous phase in Spirulina Platensis feedstock liquefaction led to a 19–30% increase in yields for different recycling numbers, which was influenced by increasing the temperature and by applying catalysts. The heterogeneous catalyst showed a considerable increase (17.8%) in yield, a decrease (9.5%) in nitrogen content, and an improved energy consumption recovery by 30.8% after single recycling. However, a slight increase (2.7%) in nitrogen content was observed after recycling twice. It is vital to reduce the amount of energy used in the hydrothermal liquefaction process to be comparable with conventional fuels. Recycling the aqueous phase reduced the energy usage considerably. Applying the homogeneous catalyst and recycling the aqueous phase twice had the highest energy efficiency (36.8%) and production yield (51.4%) for the hydrothermal liquefaction process. The generated aqueous phase in single and double recycling experiments had up to 77% and 166% more phosphate, which may be of interest for agricultural applications.

The study of cyclic variability at a n-butanol spark ignition engine fueled

Alcohols such as ethanol, methanol and butanol have gained more attraction in recent years in the use of alternative fuels at the internal combustion engines (ICE) because of their good combustion properties. The use of the butanol-gasoline blends can lead to a decrease in greenhouse gases (CO2) and pollutants such as unburnt hydrocarbons (HC), carbon monoxide (CO) but may increase nitrogen oxides (NOx). An experimental study carried out on a spark ignition engine fueled with a n-butanol-gasoline blend (10% vol. butanol - 90% vol. gasoline) at an engine load χ=55%, speed of n=2500 rpm and different air excess ratios (λ). The objective of this paper is to determine the effects of n-butanol on combustion, specifically on the cyclic variability. So, the COV values for maximum pressure, indicated mean effective pressure and angles of mass fraction burned -10%, 50% and 90%- are presented The engine fueling with butanol-gasoline blend engine leads to the decrease of the cyclic variability and the COV values don’t exceed the recommended value. A great advantage of n-butanol use is the increase of the thermal efficiency due to the stable engine operation and at lean mixtures.

Study of performance, combustion, and emissions parameters of DI-diesel engine fueled with algae biodiesel/diesel/n-pentane blends

Biodiesel extracted from Scenedesmus obliquus algae through transesterification was used in the current study. Due to the disadvantages of using pure biodiesel in engines, it was used as B50 (a blend of 50% diesel and 50% biodiesel). To enhance engine performance, n-pentane was used in different extents of 5, 10, and 15 ml per liter as an enhancer additive. Through performance tests, it was found that 15 ml of n-pentane per liter was the best addition as it caused an increase in the brake thermal efficiency of 7.1% and a decrease in brake specific fuel consumption of 6.4% compared to the elegant B50. Whereas for exhaust gases, there was an increase in nitrogen oxides, which was associated with the significant increase in exhaust temperature and the high oxygen content present in B50. In comparison, hydrocarbons emission decreased by 7.2% compared to B50 in contrast to carbon dioxide which increased by 22.3% over B50. The carbon monoxide and oxygen concentrations of the exhaust gases also decreased by 17.35% and 9.5%, respectively compared to B50. The results obtained indicated that there are a significant improvements in pressure evolution and heat release data, which depend on the role of the mixed fuel addition of n-pentane.

Impact of VOCs and NOx on Ozone Formation in Moscow

Volatile organic compounds (VOCs), ozone (O3), nitrogen oxides (NOx), carbon monoxide (CO), meteorological parameters, and total non-methane hydrocarbons (NMHC) were analyzed from simultaneous measurements at the MSU-IAP (Moscow State University—Institute of Atmospheric Physics) observational site in Moscow from 2011–2013. Seasonal and diurnal variability of the compounds was studied. The highest O3 concentration in Moscow was observed in the summer daytime periods in anticyclonic meteorological conditions under poor ventilation of the atmospheric boundary layer and high temperatures (up to 105 ppbv or 210 μg/m3). In contrast, NOx, CO, and benzene decreased from 8 a.m. to 5–6 p.m. local time (LT). The high positive correlation of daytime O3 with secondary VOCs affirmed an important role of photochemical O3 production in Moscow during the summers of 2011–2013. The summertime average concentrations of the biogenic VOCs isoprene and monoterpenes were observed to be 0.73 ppbv and 0.53 ppbv, respectively. The principal source of anthropogenic VOCs in Moscow was established to be local vehicle emissions. Yet, only about 5% of the observed isoprene was safely attributed to anthropogenic sources, suggesting significant contribution of biogenic sources into the total levels of ozone precursors. The non-linear O3–NOx dependence shows a decrease in ground-level O3 with an increase in NOx during the summers of 2011–2013, which is typical for the VOC-sensitive photochemical regime of O3 formation. Nevertheless, during the elevated ozone episodes in July 2011, the photochemical regime of ozone production was either transitional or NOx-sensitive. Contribution of various anthropogenic and biogenic VOCs into the measured ozone values was evaluated. The ozone-forming potential (OFP) of total VOCs was 31–67 μg/m3 on average and exceeded 100 μg/m3 in the top 10% of high ozone events, reaching 136 μg/m3. Acetaldehyde, 1.3-butadiene, and isoprene have the highest ozone production potential in Moscow compared to that of other measured VOCs.

Performance and Emission Characteristics of C.I Engine using Jatropha and Pongamia Mixed Biodiesel

In the present study, experiments were conducted on compression ignition engine and the performance and emission characteristics of a diesel engine using jatropha and pongamia mixed biodiesel were observed. The mixed biodiesel was mixed with diesel in different combination of MB25 (25% mixed biodiesel and 75% diesel), MB50 (50% mixed biodiesel and 50% diesel), MB75 (75% mixed biodiesel and 25% diesel), and MB100 (100% mixed biodiesel) and the results were compared with diesel. From the results, it was found that the brake thermal efficiency is increased when increasing diesel amount to mixed biodiesel and it was lower for MB100. The reduction in brake specific fuel consumption has been found for MB25, MB50, MB75 when compared to MB100. The reduction of HC (hydrocarbon), CO (carbon monoxide), smoke emissions, and increase of NOx (nitrogen oxides) for different loads were observed and compared with diesel.

Experimental Study on Performance, Emissions and Combustion Characteristics of PFI Spark Ignition Engine Fueled with E30 Equivalent Binary and Ternary GEM Blends

This work presents the concept of ternary blends of gasoline, ethanol and methanol (GEM) in which stoichiometric air to fuel ratio is controlled to 13.2, same as that of conventional binary E30 (Gasoline 70% + Ethanol 30% (v/v)) fuel blend. The formulated E30 equivalent ternary blends have approximately the same energy density, lower heating value and octane number as target binary E30 blend such that they can be a drop-in alternative to it. The experimental work was performed to investigate the performance, emission and combustion characteristics of PFI SI engine using E30 equivalent GEM blends. The engine tests were conducted at constant load while varying the engine speed from 1700 to 3300 rpm by varying the throttle position. The performance, emission and combustion results were measured and compared with pure gasoline. The results show that formulated GEM blends have similar brake thermal efficiency, in-cylinder pressure and net heat release as binary E30 blend and are improved when compared to pure gasoline. It is also noted that exhaust emissions such as Carbon monoxide (CO), unburned hydrocarbons (HC) show decreased values and increase in Nitrogen Oxide (NOx) for blended fuels compared to pure gasoline due to oxygenated nature of alcohol fuels.