Increase In Nitrogen Oxides Research Articles

Effects of aqueous carbon nanoparticles as a novel nanoadditive in water-emulsified diesel/biodiesel blends on performance and emissions parameters of a diesel engine

Biodiesel utilization is associated with reduced calorific value and increased nitrogen oxides emissions. Hence, various strategies are implemented to address these challenges such as water addition into diesel/biodiesel fuel blends. In line with that, this study was undertaken to explore the effect of water (3 wt.%) and aqueous carbon nanoparticles (38, 75, and 150 µM), as a novel fuel nanoadditive, on combustion and exhaust emissions of a diesel engine at a fixed engine speed of 1000 rev/min under four different engine loads ranging from 25% to 100% of full load conditions. Overall, the engine performance characteristics were improved by incorporating the aqueous carbon nanoparticles. In particular, the incorporation of carbon nanoparticles into water-emulsified biodiesel/diesel blends generally enhanced brake power and thermal efficiency while lowering specific fuel consumption. The most appealing performance features were observed for the emulsified fuel blend containing 38 µM carbon nanoparticles which increased brake power and brake thermal efficiency by 1.07 kW and 11.58% at full load operation, respectively, while it led to decreased brake specific fuel consumption by about 107.3 g/kWh. The addition of carbon nanoparticles to the water-emulsified fuel blends adversely affected unburned hydrocarbons and carbon monoxide emissions at full load conditions owing to an increase in carbon content of the fuel blends but it lowered nitrogen oxides emissions. The addition of water deteriorated the economic features of the fuel blend (i.e., the cost per kWh of power generated). However, carbon nanoparticles addition into the water-emulsified fuel blend partially neutralized the adverse economic effects of water due to its positive impacts on thermal efficiency. Overall, water-emulsified diesel/biodiesel containing 38 µM carbon nanoparticles could be regarded as the most promising emulsion fuel in terms of engine performance characteristics, nitrogen oxides emissions, as well as fuel economy.

Performance and emission properties of preheated and blended fennel vegetable oil in a coated diesel engine

The use of crude fennel seed oil in a diesel engine, whose combustion chamber was thermally insulated, with diesel fuel at specific rates was investigated in the present study. A single-cylinder air cooled diesel engine was used as the test engine. Plasma spray method (coated with Cr3C2 in a thickness of 300 µm) was used as the coating method. Since the atomisation and vaporisation of fennel oil are highly affected by the physical properties of the fuel, a preheating process of 100 °C was applied. Crude fennel oil mixed with diesel fuel at 30% and 50% by volume. It was shown that a preheating process of 100 °C provided a proper fuel flow and reduced the viscosity of the funnel oil and additionally, the coating process decreased carbon monoxide (CO), smoke, and hydrocarbon (HC) emissions but increased nitrogen oxides (NOx), thermal efficiency, and exhaust gas temperature (EGT).

Optimization and transesterification of sterculia oil: Assessment of engine performance, emission and combustion analysis

Biodiesel is considered as an alternative for petroleum fuels. Hence, identifying efficient biomass for biodiesel production is necessary to meet the demand. This study reports the optimum conditions of Sterculia foetida oil for biodiesel production and its engine performance, emission and combustion analysis. Gas Chromatography-Mass Spectrometry revealed the dominance of fatty acids in the order of sterculic acid (32%) > palmitic acid (15.88%) > oleic (10%) > linolenic (9.95%) > malvalic acid (9%) respectively. Oil extracted from the seeds of Sterculia foetida were purified by the degumming process to remove the unwanted impurities present in the oil. Box-Benhken design was used for optimizing transesterification process. A Maximum biodiesel yield of 90.2% was obtained at a temperature of 55 °C, catalyst concentration 1.5%, Oil to methanol ratio 1:12, agitation speed 900 rpm. ANN model was also utilized for the prediction of biodiesel yield using feed-forward backpropagation exhibited significant correlation (R2 - 0.9) with experimental results. Biodiesel blends and their properties were also analysed. Carbon monoxide and hydrocarbon emission were found to be low with the observation of increased nitrogen oxide emission. D90STB10 and D80STB20 was showing better performance and also lesser emission ompared to the conventional fuel.Combustion analysis of Sterculia foetida biodiesel (STB) and biodiesel blends (D90STB10, D80STB20, D70STB30, D60STB40 and STB100) for the various load at constant speed were analysed. Cylinder gas pressure, cumulative heat release rate, heat release rate, mass fraction burnt and mean gas temperature were discussed in the current paper.

An investigation on gasoline compression ignition (GCI) combustion in a heavy-duty diesel engine using gasoline/hydrogenated catalytic biodiesel blends

A numerical and experimental investigation on gasoline compression ignition (GCI) combustion was performed in a heavy-duty diesel engine using gasoline/hydrogenated catalytic biodiesel (HCB) blends. The effects of HCB blended ratio, initial temperature at intake valve closing (TIVC) and start of injection (SOI) on performance of the GCI engine were studied in details. Additionally, the differences between GCI and reactivity controlled compression ignition (RCCI) were also explored. The results show that HCB with high reactivity initiates the combustion of gasoline with lower reactivity, and HCB blended ratio, TIVC and SOI have remarkable impacts on thermodynamic state of the fuel/air mixing and then engine performance. As HCB blended ratio increases, the engine noise, carbon monoxide (CO) and unburned hydrocarbon (HC) emissions can be effectively suppressed with the penalties of the increased nitrogen oxides (NOx) and soot emissions. Retarded SOI results in a stable combustion, lower CO emissions while higher NOx emissions. Overall, the optimized operation range of GCI combustion is mainly limited by the engine noise, which can be relieved by multiple injection. In addition, the RCCI produces much lower engine noise compared to the GCI. However, the RCCI is more sensitive to TIVC with worse fuel economy.

Performance and emission characteristics of a CI engine using graphene oxide (GO) nano-particles additives in biodiesel-diesel blends

In the present study, the effects of graphene oxide (GO) nano-particles on performance and emissions of a diesel engine fueled with Oenothera lamarckiana biodiesel was investigated. Biodiesel was used in the blend of B20. The GO nano-particles with concentrations of 30, 60, and 90 ppm were considered for each fuel blend. Experiments were performed at a constant speed of 2100 rpm at loads of 0%, 25%, 50%, 75%, and 100%. Various parameters, such as power, exhaust gas temperature (EGT), carbon monoxide (CO), carbon dioxide (CO2), unburned hydrocarbons (UHCs), and nitrogen oxides (NOx), were investigated. Results showed that by using GO, power and EGT significantly increase. Furthermore, by using GO nano-particles, significant reductions in CO (∼5%–22%) and UHCs (∼17%–26%) were observed. However, under similar conditions, a slight increase in CO2 (∼7%–11%) and NOx (∼4%–9%) emissions observed. Finally, it can be concluded that nano-graphene oxide can be introduced as a suitable alternative fuel additive for Oenothera lamarckiana biodiesel blends.

Essential oils, asthma, thunderstorms, and plant gases: a prospective study of respiratory response to ambient biogenic volatile organic compounds (BVOCs).

Purpose: Prevailing opinion is that wind-pollinated plants affect asthma negatively and that insect- pollinated ones do not. “Thunderstorm” asthma, too, is attributed to bursting grass pollens. Additional biogenic volatile organic compounds (BVOCs) are identified here. Essential oils’ BVOCs are inhaled from plants, oil diffusers, candles, room “fresheners”, perfumes, and hygiene products. Claims of BVOC “safety” for sensitive respiratory systems are questioned.Methods: Fourteen volunteers, of mixed-age and gender, with seasonal asthma recorded peak expiratory flow (PEF) and 11 symptom scores. BVOCs were collected on Tenax tubes from ambient air in autumn and spring, as were live flower emissions, before and after a thunderstorm. Gas chromatography–mass spectrometry analysis identified frequently occurring BVOCs. Air spora, meteorological, outdoor air pollution variables, and BVOCs predict respiratory symptoms in univariate linear regression models, seasonally.Results: Increased pinene, camphor, linalool, linalyl acetate, benzaldehyde, and benzoic acid predict respiratory symptoms, including reduced PEF, and increased nasal congestion; day length, atmospheric pressure and temperature predict symptoms in both seasons, differently; other variables predict a range of symptoms (0.0001≤p≤0.05). Thunder predicts different BVOC emissions in spring, compared to autumn (p≤0.05). An uncut Grevillea flower emitted linalool and hexenal before a storm; the latter is also emitted from cut grass. Increased nitrogen oxides and pinene in autumn may combine to form harmful oxidation products.Conclusion: This research supports BVOCs as contributors to seasonal asthma and allergic rhinitis, and “thunderstorm” asthma. Pinene emissions from Myrtaceae species (Eucalyptus, Melaleuca, Leptospermum, Callistemon), Brassicaceae (canola), and conifers, worldwide, may induce respiratory inflammation and maintain it, by inhibiting eosinophilic apoptosis. Widely used essential oil products containing BVOCs, like linalool, are associated here with respiratory symptoms. Lagged responses suggest that users’ cognitive associations between exposure and response are unlikely, increasing potential for impaired health for vulnerable children.

Influence of injection timing and exhaust gas recirculation (EGR) rate on lemon peel oil-fuelled CI engine.

In the current phase of world economy, the utilization of the petroleum-based fossil fuels has drastically surpassed the supply. This scenario supplements to the fact that there is an ever increasing necessity for industrialization, specifically in the transportation sector. This requirement and supply of the petroleum and diesel fuels have an astounding impact over the market economy and related commodities. Low viscous and low cetane number biofuels are getting more attention for their usage in engine applications without any further processing. In the present work, lemon peel oil is being fuelled in diesel engine at different timing of injection and exhaust gas recirculation rates. Operation of lemon peel oil (LPO) at standard operating conditions results in increased brake thermal efficiency by consuming less fuel when compared with diesel fuel. The LPO biofuel properties such as boiling point and viscosity being lower leads to better evaporation capacity and thereby results in complete combustion. The advancement in injection timing of 25° bTDC and 27° bTDC resulted in the efficiency increment of 2.17% and 6.19% respectively. Furthermore, the smoke, carbon monoxide and hydrocarbon emissions are decreased in consequence on increased nitrogen oxide (NOx) emissions. Hence, in order to decrease the content of nitrogen oxide emissions in the exhaust, exhaust gas recirculation (EGR) has been implemented in the present work. For EGR rate of 10% and 20%, the NOx emissions is reduced by 43% and 46% respectively for 27° bTDC injection timing. Thus, the advancement of injection timing with optimum EGR is a viable option for the lemon peel oil biofuel in diesel engine with superior performance and emission output.

Experimental Investigation of Diesel Engine Performance, Combustion and Emissions Using a Novel Series of Dioctyl Phthalate (DOP) Biofuels Derived from Microalgae

Physico-chemical properties of microalgae biodiesel depend on the microalgae species and oil extraction method. Dioctyl phthalate (DOP) is a clear, colourless and viscous liquid as a plasticizer. It is used in the processing of polyvinyl chloride (PVC) resin and polymers. A new potential biofuel, hydrothermally liquefied microalgae bio-oil can contain nearly 11% (by mass) of DOP. This study investigated the feasibility of using up to 20% DOP blended in 80% diesel fuel (v/v) in an existing diesel engine, and assessed the performance and exhaust emissions. Despite reasonable differences in density, viscosity, surface tension, and boiling point, blends of DOP and diesel fuel were found to be entirely miscible and no separation was observed at any stage during prolonged miscibility tests. The engine test study found a slight decrease in peak cylinder pressure, brake, and indicated mean effective pressure, indicated power, brake power, and indicated and brake thermal efficiency with DOP blended fuels, where the specific fuel consumption increased. This is due to the presence of 16.4% oxygen in neat DOP, responsible for the relatively lower heating value, compared to that of diesel. The emission tests revealed a slight increase in nitrogen oxides (NOx) and carbon monoxide (CO) emissions from DOP blended fuels. However, particulate matter (PM) emissions were lower from DOP blended fuels, although some inconsistency in particle number (PN) was present among different engine loads.

Thermal efficiency enhancement using a ceramic coating on the cylinder liner and the piston head of the IC engine

In general, only 40% of the power produced in the engine is converted into useful work other than that 30% of heat escape through exhaust and 30% of heat is which cannot be converted into useful work is removed as waste heat with the help of the cooling system. To convert this waste heat into useful work, the cylinder liners and piston head are coated with ceramic coating. This will lead to a reduction in heat transfer through the engine, involving an increased efficiency. The higher gas temperature should reduce the concentration of incomplete combustion products at the expense of an increase in nitrogen oxides (NOx). However, a decrease in carbon monoxide (CO) and unburned hydrocarbons (HC) is observed. Here we are going to analyse the uncoated cylinder with coated one using ANSYS and in the experimental method using a thermal image camera. The result depicted that the ceramic coated cylinder is more efficient than the uncoated one.

Effect of antioxidant additives on performance and emission behavior of biodiesel fueled DI diesel engine

ABSTRACTMany recent studies show that 20% proportion of biodiesel–diesel blend (A20) can substantially reduce the hydrocarbon, carbon monoxide, and smoke emissions. However, there is a slight increase in oxides of nitrogen (NOx) emission for A20 than that of diesel and it is barrier to market expansion. The addition of antioxidant additives is the most effective method for mitigating the NOx emission. Hence, this present work aims to investigate the effect of antioxidant additives on NOx emission in an Annona biodiesel-operated diesel engine. The antioxidant additives such as p-phenylenediamine (PPDA), A-tocopheryl acetate, and L-ascorbic acid are used in the present investigation. It is evidently proved from the experimental investigation that use of antioxidant additive is effectively controlling the NOx emission in diesel engine. Result shows that 250 mg concentration of PPDA additive with A20 is optimum for NOx mitigation up to 25.7% when compared to that of diesel without any major modifications.

Investigation of diesel engine performance and exhaust emissions of microalgae fuel components in a turbocharged diesel engine

Microalgae are a promising feedstock for alternative fuel for compression ignition engines due to their positive contribution to reducing greenhouse gas emissions. Microalgae are gaining significant interest as they can produce more oil than any oilseed plants. Unlike some other plant oils, the use of microalgae as an alternative to fossil fuels, can overcome food versus fuel conflict. In the current investigation, five different chemical components of microalgae hydrothermal liquefaction (HTL) biocrude paraffin, xylene, cyclo-pentanone, dioctyl-phthalate and butanol were mixed in equal volumes. Commercial diesel fuel was used as a reference fuel. The first blend consisted of 5 vol% of each of the 5 components was mixed with 75 vol% diesel. The blend is called as B1. The second blend consisted of 10 vol% of each of the 5 components was mixed with 50 vol% of diesel. This blend is called B2. The neat diesel (100% pure diesel) is called as 100D. The engine used in this study was a six-cylinder high-pressure common rail direct injection diesel engine fitted with a turbocharger. This study deals with engine performance, combustion and exhaust emission characteristics comparing diesel, B1 and B2 blends. The experimental results indicated a general reduction in both particle mass (PM) and total particle number (PN) emissions with both blends compared to those of diesel. Increase in nitrogen oxides (NOx) emissions at all four engine loads were found with both B1 and B2 blends. It was realised that the drop or rise of emissions was mainly a function of fuel-bound oxygen.

A comprehensive study on emission and performance characteristics of a diesel engine fueled with nanoparticle-blended biodiesel.

The present work is aimed to analyze the performance and emission characteristics of mahua biodiesel-fueled diesel engine with copper oxide nanoparticle at various particle sizes (10 and 20nm) and the results compared with conventional diesel fuel (BD). Experiments were conducted in a four-stroke, single-cylinder, constant speed, and naturally aspirated research diesel engine with an eddy current dynamometer. Conventional transesterification process is carried out to convert the raw mahua oil into mahua oil biodiesel (BD100). Copper oxide (CuO) was chosen as a nanoparticle; the mass fraction of 100ppm and the particle sizes of 10 and 20nm were blended with mahua oil methyl ester using an ultrasonicator, and the physicochemical properties were measured. The physicochemical properties of BD100 and nanoparticle-included BD100 are at par with EN14214 limits. Brake-specific fuel consumption (BSFC) of BD100 is higher than that of diesel, and brake thermal efficiency (BTE) is lower than that of diesel (D100). The inclusion of 10-nm particle size of CuO nanoparticle in BD100 improves the BSFC and BTE by 1.3 and 0.7%, respectively, when compared with BD100. The CuO nanoparticle inclusion at 20-nm nanoparticle in biodiesel further improves the performance parameters than those at 10-nm nanoparticle. Further, the BD100 promotes a lower level of smoke emissions, carbon monoxide (CO), and hydrocarbon (HC) and with a prominent increase in oxides of nitrogen (NOx) emissions. The inclusion of 10-nm particle size of CuO nanoparticle in BD100 reduces the NOx, HC, CO, and smoke emission by 3.9, 5.6, 4.9, and 2.8%, respectively, at peak load condition when compared with BD100. The addition of CuO nanoparticle at 20-nm nanoparticle in biodiesel further reduces the NOx, HC, CO, and smoke emissions.

Numerical simulation on combustion process of a hydrogen direct-injection stratified gasoline Wankel engine by synchronous and asynchronous ignition modes

A Wankel engine with hydrogen direct-injection enrichment is recognized as an attractive method to enhance combustion efficiency. In this paper, on the basis of the chemical kinetic mechanisms, a three-dimensional simulation model was established and validated by the measured results. The ignition and combustion processes in a gasoline Wankel engine with hydrogen direct-injection enrichment were implemented for numerical simulation. The influence of twin-spark timing was firstly analyzed by synchronous ignition. Further investigation was then conducted to simulate how to effect the combustion by asynchronous ignition based on the favorable synchronous ignition timing. Results showed that, the average flow velocities were 18.8, 20.7, 23.6, and 25.4 m/s for the spark timings (ST) of 45, 35, 25, and 15°CA BTDC respectively. With retarded ST, the rich equivalence ratio approached to twin-spark plug continually. For synchronous ignition, at a larger advance of ST, the duration between the timing of the vortex dissipation and ST was longer, and the ignition delay was more prolonged. As the ST advanced, the combustion rate was enhanced with the increment in chamber temperature, the reactants (C8H18, C7H16, and H2) consumption and intermediates (H2O2, OH, and CH2O) generation were accelerated, the maximum H2O2 and CH2O decreased whereas the maximum OH increased, and nitrogen oxides (NOx) and carbon monoxide (CO) increased sequentially. For asynchronous ignition, the accelerated flame front was in accordance with the rotating direction of the rotor while the opposite direction was inhibited during the combustion process. An earlier ignition of leading-spark plug (L-plug) or trailing-spark plug (T-plug) provided the higher flame speed and faster H2 consumption, which contributed to the higher in-cylinder pressure, combustion temperature, and NOx and CO production. The preferable ignition and combustion characteristics was realized when the L-plug angle was 25°CA BTDC, and the T-plug angle was 35°CA BTDC. Compared with the favorable synchronous ignition timing, the flame propagation and H2 consumption were expedited, the peak pressure increased by 2.8%, the corresponding crank position advanced by 3°CA and there was no increase in NOx and CO generation. Therefore, it was recommended in engineering applications that the ST of T-plug advanced appropriately while the ST of L-plug remained constant.

Comparative analysis of combustion, performance and emission phenomenon of a CI engine fuelled with algal and cotton seed biodiesel

ABSTRACT The present study compares the effect of algal and cotton seed biodiesel in a single cylinder compression ignition engine. Bio-oil extraction was achieved through grinding operation and soxhlet lipid extraction from cotton seed and Stoechospermum marginatum marco-algae respectively which was followed by single stage transesterification process. Gas-chromatography mass-spectrometry analysis revealed the presence of linoleic acid in prominent proportion for algal biodiesel. The physio-chemical properties of cotton seed and algal biodiesel were comparative and found to be within ASTM D6751 standards. At rated load, neat algal biodiesel showed elevated in-cylinder pressure, rate of pressure rise and rate of heat release. Higher ignition delay with neat biodiesel resulted in prolonged combustion duration. Algal biodiesel produced higher brake thermal efficiency than cotton seed biodiesel along with 16.67% of lower BSFC at full load. Furthermore, lower unburned hydrocarbon, smoke and carbon monoxide was evidenced especially at full load with a significant increase in oxides of nitrogen.

Ursolic acid prevents doxorubicin-induced cardiac toxicity in mice through eNOS activation and inhibition of eNOS uncoupling.

In addition to the known antitumour effects of ursolic acid (UA), increasing evidence indicates that this molecule plays a role in cardiac protection. In this study, the effects of ursolic acid on the heart in mice treated with doxorubicin (DOX) were assessed. The results showed that ursolic acid improved left ventrical fractional shortening (LVFS) and left ventrical ejection fraction (LVEF) of the heart, increased nitrogen oxide (NO) levels, inhibited reactive oxygen species (ROS) production and decreased cardiac apoptosis in mice treated with doxorubicin. Mechanistically, ursolic acid increased AKT and endothelial nitric‐oxide synthase (eNOS) phosphorylation levels, and enhanced eNOS expression, while inhibiting doxorubicin induced eNOS uncoupling through NADPH oxidase 4 (NOX4) down‐regulation. These effects of ursolic acid resulted in heart protection from doxorubicin‐induced injury. Therefore, ursolic acid may be considered a potential therapeutic agent for doxorubicin‐associated cardiac toxicity in clinical practice.

Performance and emission analysis of methyl ester of Azolla algae with TiO2 Nano additive for diesel engine

ABSTRACT The present work investigates the effect of using TiO2 Nanoparticles at a different proportion of Azolla algae methyl ester, in a four-stroke single cylinder diesel engine. Biodiesel can be obtained from Azolla algae due to the presence of high oil content. The oil was extracted from Azolla algae by means of the Soxhlet extraction method which was compared to be more effective than the oil obtained by means of hydraulic pressing machine. The obtained oil was converted to biodiesel by means of transesterification process. The fuel properties of the prepared Azolla methyl ester found to confirm with the ASTM standards. TiO2 Nanoparticles were synthesized by means of ball milling process and characterized by means of Scanning Electron Microscope (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR) and X-Ray Diffraction (XRD) techniques. In the present study, the performance and emission characteristics of diesel engine were analyzed with the addition of TiO2 Nanoparticles to Azolla oil methyl ester (25,50,75 and100 ppm) and compared with that of diesel. The % decrease in Brake Specific Fuel Consumption (BSFC) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 7.81, 12.05, 19.71, and 23.53, respectively, when compared to B20. The % increase in Brake Thermal Efficiency (BTE) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 2.60, 8.49, 8.79 and 13.38, respectively, when compared to B20. The % decrease in Carbon monoxide (CO) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 21.15, 51.92, 54.80, and 57.30, respectively, when compared to B20. The % decrease in Hydro Carbon (HC) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 7.53,8.36,10.04 and 12.97, respectively, when compared to B20. The % increase in Oxides of Nitrogen (NOx) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 5.44, 7.85, 8.67, and 9.16, respectively, when compared to B20. The % decrease in smoke for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 18.02, 30.18, 31.98 and 36.04, respectively, when compared to B20. Addition of TiO2 Nanoparticles with the Azolla biodiesel is found to be an effective approach to improve the performance and emission characteristics of a diesel engine without any modification.

Experimental Examination of Performance, Exhaust Emission and Combustion Behaviours of A Ci Engine Fuelled With Biodiesel/Diesel Fuel Blends

The main objective of this study is to evaluate the effect on diesel engine performance, exhaust emission and combustion characteristics of canola oil biodiesel. The biodiesel was blended with petroleum-based diesel fuel (DF) by 10% (B10), 20% (B20) and 50% (B50) volumetrically. Engine tests were carried out on a direct injection, single-cylinder, compression ignition engine at different engine loads and the results were compared with the reference DF. The results showed that the maximum cylinder pressure and heat release rate values of DF were higher than those of the biodiesel blends at all engine loads. The addition of biodiesel to DF increased the brake specific fuel consumption (BSFC) and decreased the brake thermal efficiency (BTE) at all engine loads. In addition, biodiesel blends caused a slight increase in nitrogen oxide (NOx) emissions while causing a decrease in smoke opacity and carbon monoxide (CO) emissions.

Effects of Exhaust Gas Recirculation Constituents on Methyl Decanoate Auto-Ignition: A Kinetic Study

Biodiesel engines are found to have improved soot, hydrocarbon (HC), and carbon monoxide (CO) emissions, with modestly increased nitrogen oxides (NOx) emissions. Exhaust gas recirculation (EGR) could be used for the NOx emissions control, especially in the fuel-kinetics-dominated engine combustion concepts. A detailed chemical kinetic model of methyl decanoate (MD), a biodiesel surrogate fuel, was used here to simulate the two-stage auto-ignition process of biodiesel with EGR addition. The effects of EGR constituents, including carbon dioxide (CO2), water vapor (H2O), CO and H2, were identified in a constant-pressure ignition process and in a variable pressure, variable volume process. Firstly, numerical methods were used to isolate the dilution, thermal, and chemical effects of CO2 and H2O at a constant pressure. It was found that in the biodiesel auto-ignition processes, the dilution effects of CO2 and H2O always played the primary role. Their thermal and chemical effects mainly influenced the second-stage ignition, and the chemical effect of H2O was more significant than CO2. The triple effects of CO and H2 were also analyzed at the same temperature and pressure conditions. Additionally, the sensitivity analysis and reaction pathway analysis were conducted to elucidate the chemical effects of CO and H2 on the ignition processes at different temperatures. Finally, based on a variable pressure, variable volume model simulating the engine compression stroke, the effects of CO2, H2O, CO and H2 addition under the engine operational conditions were studied and compared to those under the constant pressure conditions.

Potential impacts of emissions associated with unconventional hydrocarbon extraction on UK air quality and human health

Here, we report the first results of model sensitivity simulations to assess the potential impacts of emissions related to future activities linked to unconventional hydrocarbon extraction (fracking) in the UK on air pollution and human health. These simulations were performed with the Met Office Air Quality in the Unified Model, a new air quality-forecasting model, and included a wide range of extra emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) to reflect emissions from the full life cycle of fracking-related activities and simulate the impacts of these compounds on levels of nitrogen dioxide (NO2) and ozone (O3). These model simulations highlight that increases in NOx and VOC emissions associated with unconventional hydrocarbon extraction could lead to large local increases in the monthly means of daily 1-h maximum NO2 of up to + 30 ppb and decreases in the maximum daily 8-h mean O3 up to − 6 ppb in the summertime. Broadly speaking, our simulations indicate increases in both of these compounds across the UK air shed throughout the year. Changes in the 1-h maximum of NO2 and 8-h mean of O3 are particularly important for their human health impacts. These respective changes in NO2 and O3 would contribute to approximately 110 (range 50–530) extra premature-deaths a year across the UK based on the use of recently reported concentration response functions for changes in annual average NO2 and O3 exposure. As such, we conclude that the release of emissions of VOCs and NOx be highly controlled to prevent deleterious health impacts.

The Effect of Biodiesel Derived from Waste Oil on Engine Performance and Emission Characteristics

To produce biodiesel from waste oil and use it as an alternative fuel in compression ignition (CI) engines is an efficient way to eliminate this harmful compound. In this experimental study, the effects of biodiesel derived from waste oil on emission and performance characteristics of CI engine were investigated. The production of biodiesel was realized at the condition: 9wt% acid catalyst amount, 9:1 molar ratio, 60oC reaction temperature and 120min reaction time. Biodiesel and diesel were mixed with different volumetric ratios and the properties of each blend were analyzed. Each blend was tested with a direct injection CI engine to see the effect of biodiesel on performance and emission characteristics. In conclusion, blends showed similar results in terms of performance comparing to diesel. The use of biodiesel derived from waste oil led to decrease in hydrocarbon (HC), carbon monoxide (CO) emissions and smoke opacity up to 81.25%, 55.02% and 40.48% respectively while led to slight increase in nitrogen oxides (NOx) emissions in general.