UHC Emissions Research Articles

A Multi-Objective Optimization of Output Parameters of a Single Cylinder Diesel Engine Running Methyl Esters and Different Additives: Taguchi-Fuzzy Based Approach

The continuous dependency on fossil fuels for energy requirements, transportation and power generation sectors the research has increased considerably on alternative source of fuel. Recently, it can be seen that Madhuca Indica Methyl Ester is gaining popularity due to its economical nature, the similarity with diesel’s properties. The primary aim of this research is to implement blends of Machuca Indica biodiesel using two different additives, 2-EHN and triacetin in different ratios for investigating single cylinder direct injection diesel engine output. In the current analysis, a Taguchi optimisation technique based on fuzzy logic is used to find the optimal combination of emission and performance parameters in order to make prediction of optimal input blends. It shows that the cylinder pressure of the blends is always higher than diesel. Among all blends, BL2 possesses the highest cylinder pressure under various load conditions. In terms of brake thermal efficiency, Among the blends, BL2 and BL3 possess BTE 12%, and 11% more than plain diesel in full load respectively. At maximum load, BSFC of Blend 2, 3 and 6 are (25, 22.5, 20)% less than plain diesel. BL5, BL6 and BL7 produced 3%, 1% and 0.3% less NOx than diesel. It is seen that BL2, BL3 and BL5 had lowermost UHC emission of 34%, 27% and 26% than pure diesel at maximum load. This multi-objective optimization technique shows that the blend BL6 have optimal MPCI value of 0.75.

Evaluation of animal fat based biodiesel blends and effects of exhaust gas recirculation on the suitable blend in single cylinder four stroke diesel engine

ABSTRACT An experimental study is carried out to evaluate the effects of animal fat biodiesel blends with diesel and exhaust gas recirculation (EGR) for the suitable biodiesel blend selected on performance, emission, and combustion characteristics in single cylinder four-stroke diesel engine. Animal fat biodiesel (AFB100) is prepared through the transesterification process. Diesel fuel is mixed with animal fat biodiesel and the animal fat-based biodiesel blends are prepared such as AFBB20, AFBB40, and AFBB60. Few important properties for the prepared blends are found and tabulated in table 1. In this investigation, AFBB20 yields better performance and emission characteristics compared to other tested biodiesel blends. Increasing NOx emissions is not good for the environment and creates health issues. To reduce the NOx emission for the selected blend AFBB20, the EGR technique is applied by 0%, 10%, 20%, and 30%, and investigates in the same engine. In the EGR investigation, lower brake specific fuel consumption and higher BTE are found in 10% EGR. Lowered CO and UHC emissions are found in EGR 10%. Compared to 0% EGR, drastic reduction in NOx emission is found by 16.5% and 17.5% reduced smoke emission is found in 10% EGR rate compared to AFBB20. Abbreviations: BSFC: Brake specific fuel consumption; BTE: Brake thermal efficiency; CO: carbon monoxide; UHC: unburned hydrocarbons; NOx: nitrogen oxides; EGT: Exhaust gas temperature; CP: Cylinder Pressure; HRR: Heat release rate; bTDC: Before top dead center; aTDC: after top dead center; ppm: parts per million; IC: internal combustion engine; CI: compression ignition; EGR: exhaust gas recirculation; DAQ: data acquisition system; PD 100: Petro diesel; AFBB: Animal fat biodiesel blends; AFB100: animal fat biodiesel; AFBB20 (PD 80% + AFB 20% by volume),; AFBB40 (PD 60% + AFB 40% by volume) AFBB60 (PD 40% + AFB 60% by volume)

Water-containing i-propanol-n-butanol-ethanol (IBE) as a next-generation biofuel of n-butanol for diesel engine

The high emission level of diesel engines has been an issue of global concern and the sophisticated means of controlling the emissions were not cost-effective. In this work, effects of water addition in a bio-derived fuel to mitigate engine emissions and enhances the brake thermal efficiency have been investigated. Four test samples including IBE10, IBE30, IBE29.5W0.5 and IBE29W1 have been prepared and tested in a diesel engine. The engine combustion characteristics, performance and emissions have been observed. It has been established that the water containing blends improve the BTE, BSFC and further reduces emissions at varying loads. In comparison with IBE30, IBE29W1 (29 vol. % IBE, 1 vol. % water and 90 vol. % diesel) has shown decreasing peak in-cylinder pressure and increases ignition delay and combustion duration by 0.13% – 4.8 %, 0.5% – 12.4 % and 0.26% – 3.8 % respectively. As for the engine performance, BTE has been increased by 2.6 % – 14.1% and BSFC decreased by 0.1% – 15 %, respectively, and the emissions of UHC, smoke, CO and NOx emissions was decreased by 21% – 42.6%, 0% – 21.7%, 5.4% –11%, and 0.64% – 9%, at varying loading conditions respectively.

Novel environmentally friendly fuel: The effect of adding graphene quantum dot (GQD) nanoparticles with ethanol-biodiesel blends on the performance and emission characteristics of a diesel engine

Biodiesel fuel has some disadvantages including increase in NOx, poor atomization and incomplete combustion. Additives and catalysts can be used to reduce the negative effects of biodiesel fuel. In addition, the use of metal oxide and metal nanoparticles causes environmental hazards. However, using biodegradable nanoparticles can significantly reduce such concerns. The present study investigated the effect of adding GQD + E to B10 fuel on the emission and performance characteristics of a diesel engine. B10 was blended with GQD (90 ppm) and bioethanol (E2, E4, E6 and E8% vol). Performance and emission characteristics, including power, torque, SFC, CO, CO2, UHC and NOx emissions were measured at the speeds of 1800, 2100 and 2400 rpm and full load mode. According to the results, the addition of GQD + E to B10 improved torque and power and decreased SFC, CO, UHC and NOx. Finally, the B10 + E6 + GQD90 fuel was the best fuel regarding improved engine performance and reduced exhaust emission. The average of changes in power and torque, SFC, CO, UHC and NOx compared to D100 for B10 + E6 + GQD90 were + 15.69%, +15.39%, −17.58%, −30.30%, −38.91% and −1.54%, respectively.

Determination and utilization of optimal diesel/n-butanol/biogas derivation for small utility dual fuel diesel engine

Aggregating pollution along with exhausting fossil fuels throughout the world has enforced the inventors to explore for an alternative fuel that can be utilized in diesel engines. Presently, investigators and professionals have originated that biodiesel in association with higher alcohols and gaseous fuel can be an alternative for the current circumstances. Anterior examinations have rendered that biodiesel and higher alcohol along with gaseous fuels can support in upgrading the performance and denigrating detrimental exhaust emanations in a diesel engine. This research aimed to investigate the impacts of engine load, n-butanol concentration, and biogas quantity on emissions and performance characteristics of a small utility compression ignition engine. The different engine load (20–100% of brake power), n-butanol concentration (0–20%) and biogas flow rate (0.5–2 kg/h) were used as input variables. The multi-criteria decision analysis based on response surface method techniques was employed to find the optimal values of engine working conditions fuelled with diesel/n-butanol/biogas fuel blends. In the optimization process, five objective functions (BTE, NOX, CO, UHC, and soot) were considered to be optimized based on the defined criteria. The addition of n-butanol in diesel has shown a favourable impact on biogas operated dual-fuel engine in terms of performance and emissions characteristics. The approach of desirability was applied to obtain the best operating conditions of the engine. The optimum value of engine load, n-butanol concentration, and biogas flow rate were found as 78.89%, 20%, and 1.37 kg/h, respectively. At this condition, the optimal value of BTE, UHC, CO, NOX, and smoke emissions were found to be 19.19%, 0.36g/kWh, 0.04%, 14.51g/kWh, and 22.32%, respectively. A high desirability value of 0.77 was obtained for the suggested condition, showing the efficiency of the derived models for response parameters.

Multi-objective optimization of diesel engine performances and exhaust emissions characteristics of Hermetia illucens larvae oil-diesel fuel blends using response surface methodology

ABSTRACT This paper investigates the utilization of response surface methodology (RSM) to optimize the engine performance and exhaust emission parameters of a compression ignition (CI) engine which operate using neat Hermetia illucens larvae oil (HILO) blends of 25, 50, 75, and 100% named as B25, B50, B75, and B100. The engine testing experiments were operated at different engine loads for each fuel blends and at 25 different experimental conditions. The brake power and brake mean effective pressure (BMEP) of HILO-diesel fuel blends were almost similar with diesel fuel while the brake specific fuel consumption (BSFC) was slightly increased. Furthermore, NOx emissions decreased with HILO addition. However CO, CO2, and UHC emissions increased. Optimization of independent variables was achieved via the RSM desirability approach with the aim of maximizing performance and minimizing emissions parameters. Therefore, the engine performance and emissions parameters for various HILO-diesel fuel blends were observed nearly similar to diesel fuel. An engine load of 92.72% and a blend of 6.43% of HILO with 93.57% diesel fuel were observed to be an optimum input point. The finding of this investigation exposed that at optimum input point, the values of the brake power, BMEP, BSFC, BTE, CO, CO2, UHC, and NOx were found to be 3.21 kW, 399.70 kPa, 0.071 mg/J, 27.26, 0.024, 5.30%, 0.62 ppm, and 537.93 ppm, respectively.

On the Turbulence-Chemistry Interaction of an HCCI Combustion Engine

A numerical study was carried out to evaluate the influence of engine combustion chamber geometry and operating conditions on the performance and emissions of a homogeneous charge compression ignition (HCCI) engine. Combustion in an HCCI engine is a very complex phenomenon that is influenced by several factors that need to be controlled, such as gas temperature, heat transfer, turbulence and auto-ignition of the gas mixture. An eddy dissipation concept (EDC) combustion model was used to take into account the interaction between turbulence and chemistry. The model assumed that reactions occur in small turbulent structures called fine-scales, whose characteristic lengths and times depend mainly on the turbulence level. The model parameters were slightly modified with respect to the standard model proposed by Magnussen, to correctly simulate the characteristics of the HCCI combustion process. A reduced iso-octane chemical mechanism with 186 species and 914 chemical reactions was employed together with a sub-mechanism for NOx. The model was validated by comparing the results with available experimental data in terms of pressure and instantaneous heat release rate. Two engine chamber geometries with and without a cavity in the piston were considered, respectively. The two engines provided significant differences in terms of fluid-dynamic patterns and turbulence intensity levels in the combustion chamber. The results show that combustion started earlier and proceeded faster for the flat piston, leading to an increase in both the peak pressure and gross indicated mean effective pressure, as well as a reduction of CO and UHC emissions. An additional analysis was performed by considering a case without swirl for the flat-piston case. Such an analysis shows that the swirl motion reduces the time duration of combustion and slightly increases the gross indicated work per cycle.

Diesel/ biodiesel /silver thiocyanate nanoparticles/hydrogen peroxide blends as new fuel for enhancement of performance, combustion, and Emission characteristics of a diesel engine

In the present study, sunflower and soybean oil commixture with 50:50 V/V % had been used to produce biodiesel by using a homogeneously catalyzed transesterification. The influence of biodiesel blend, nano blended fuel, and nanoemulsion fuel blends on the combustion, performance, as well as emissions of DI diesel engine, had been examined in the laboratory at various engine loads and a steady speed of 1400 rpm. Volumetric proportions of fuel mixtures: D50B50N000 (50% diesel-50% biodiesel), D50B50N200 (D50B50 + 200 ppm silver thiocyanate AgSCN (SCP1∖), D50B50N200 + 2% hydrogen peroxide (H2O2), and D50B50N200 + 4%H2O2 were arranged to fuelling a one-cylinder engine. The exhaust emissions of the engine were compared at pure diesel fuel and biodiesel blend D50B50N000, which indicated a reduction in CO, UHC, and NOx emissions upon adding a 200-ppm of silver thiocyanate SCP1∖ as a nano additive. This reduction increased upon adding and increasing the volumetric percentage of H2O2 where the D50B50N200 + 4% H2O2 fuel blend has lower emission values. The results show that CO2 emissions for the investigated fuel blends were elevated than diesel fuel. The presence of nanosized AgSCN and H2O2 enhanced the combustion process because of elevated nanoparticle surface/volume ratio and the occurrence of micro-explosion phenomena of the sprayed fuel particles, which increased the in-cylinder pressure and heat release rate (HRR). A noticeable decrease in brake specific fuel consumption (BSFC) was observed owing to the positive effect of using nano biodiesel blend and nanoemulsion fuels. A consequent increment in brake thermal efficiency (BTE) was indicated for nano biodiesel blend and nanoemulsion biodiesel blend fuels, where D50B50N200 + 4%H2O2 has the highest BTE of 27.16% compared to all tested fuels. Exhaust gas temperature (EGT) values were evaluated and analyzed for all tested fuels.

Effect of reformed biogas as a low reactivity fuel on performance and emissions of a RCCI engine with reformed biogas/diesel dual-fuel combustion

Biogas can be used as a less expensive continuance renewable fuel in internal combustion engines. However, variety in raw materials and process of biogas production results in different components and percentages of various elements, including methane. These differences make it difficult to control the combustion, effectively, in internal combustion engines. In this research, under cleaning and reforming process, biogas components were fixed. Then the effect of reformed biogas (R.BG) was investigated, numerically, on the combustion behavior, performance and emissions characteristics of a RCCI engine. A 3D-computational modeling has been performed to validate a single-cylinder compression ignition engine in conventional diesel and dual-fuel operations at 9 bar IMEP, 1300 rpm. Then, the combustion model of the RCCI engine was simulated by replacing diesel fuel with 20%, 40% and 60% of R.BG as a low reactivity fuel while remaining constant input total fuel energy per cycle. The results demonstrated that when the R.BG substitution ratio increases with a constant equivalence ratio of 0.43, the mean combustion temperature decreases to 1354 K, 1312 K, 1292 K which are about 3.5%, 6.6%, 7.9% lower than the conventional diesel combustion, respectively. The maximum in-cylinder pressure increases up to 22.63%. Instead, it results in 2.3%, 7.9%, and 14.5% engine power output losses, respectively. Also, the NOx emission, against CO, is decreased by 50%. Soot and UHC emissions were found to be slightly decreased while was used R.BG more than 40%.

Effect of piston bowl geometry and compression ratio on in-cylinder combustion and engine performance in a gasoline direct-injection compression ignition engine under different injection conditions

Low temperature combustion (LTC) of high-octane number fuels in compression ignition engines offers an opportunity to simultaneously achieve high engine thermal efficiency and low emissions of NOx and particulate matter without using expensive after-treatment technologies. LTC engines are known to be sensitive to the operation conditions and combustor geometry. It is important to understand the fundamental flow and combustion physics in order to develop the technology further for commercial application. A joint numerical and experimental investigation was conducted in a heavy-duty compression ignition engine using a primary reference fuel with an octane number of 81 to investigate the effects of injection timing, piston geometry, and compression ratio (CR) on the fuel/air mixing and combustion covering different regimes of LTC engines, homogeneous charge compression ignition (HCCI), partially premixed combustion (PPC), and the transition regime from HCCI to PPC. The results show that with the same combustion timing, a higher CR leads to a lower NOx, but a higher emission of UHC and CO. The piston geometry shows a significant impact on the combustion and emission process in the transition regime while it has minor influence in the HCCI and PPC regimes. It is found that high engine efficiency and low emissions of NOx, CO and UHC can be achieved in the earlier PPC regime and later transition regime. The fundamental reason behind this is the stratification of the mixture in composition, temperature and reactivity, which is dictated by the interaction between the spray and the cylinder/piston walls.

EGR rate 변화에 따른 바이오디젤 정적 연소 특성에 관한 수치해석 연구

This paper was conducted to investigate the effect of EGR on the combustion characteristics, NO<SUB>X</SUB> and CO formation characteristics of constant volume combustion of the biodiesel fuel. To achieve this, methyl decanoate, methyl 9 decenoate, and n-heptane species were applied for the simulation of the biodiesel and diesel chemical reactions during the constant volume combustion process. The analysis of biodiesel-EGR combustion was performed by simultaneously considering the mole fraction which was composed of the N₂, H₂O, CO₂, and O₂ species according to the EGR rate (10~60%). As a result of the combustion characteristics, the maximum OH radical was reduced as the EGR rate increase, and the ignition delay was increased at the same time. Most of NO<SUB>X</SUB> emission was generated by the thermal NO<SUB>X</SUB> reaction, and it was not emitted after the EGR rate of 30% conditions due to the decrease of combustion temperature and oxygen concentration. The reactivity of CO generation was showed the high absolute rate of production in the reaction path related to the reactions of HCO radical, and it has a trade-off relationship with the tendency of NO<SUB>X</SUB> emissions. In addition, it was indicated that the UHC emission increased rapidly since the chemical reactions related to the fuel oxidation did not occur actively when the ambient temperature was 800~1,000 K and the EGR rate was 60% conditions.

Multi-objective optimization of performance and emissions characteristics of a variable compression ratio diesel engine running with biogas-diesel fuel using response surface techniques

ABSTRACT Rapidly intensifying necessitates of energy and depletion of accessible fossil resources has made a remarkable interest in investigation of the alternative fuels. The current investigational work was performed to examine the use of multi-objective optimization (MOP) based on response surface methodology (RSM) to investigate the impact of compression ratio (CR), biogas flow rate and engine load on the performance of dual-fuel engine. An engine load of 80%, compression ratio of 18, and biogas flow rate of 2.8 kg/h were observed to be optimal condition. According to these optimized parameters, the value of BTE, NOX, UHC, CO and smoke opacity were found to be 18.51(%), 13.5 (g/kW.hr), 0.49 (g/kW.hr), CO (0.08% vol.) and 23.6 (%), respectively. Compared with conventional diesel fuel, dual-fuel operational mode can improve brake specific energy consumption and reduce NOX as well as Smoke opacity, while producing higher emissions of CO and UHC.

Experimental Study on Performance and Emission Characteristic of Diesel Engine using Sunflower oil Biodiesel Blends

Biodiesel fuel is a liquid biofuel produced by chemical process form new and used phytogenic oils, animal fats. Biodiesel fuels can be utilization alone or mixing with the pure diesel at different proportion. In the present work a diesel engine type (FIAT) , four cylinder, variable speed, direct injection was operated by sunflower oil methyl ester , biodiesel at different blend ratio . five different ratio of biodiesel blends 10%, 20%, 30%, 40%, and 50% by volume is used in this study and compared with using of pure diesel at variable loads and variable engine speed. The effect of biodiesel additive to pure diesel on the performance and emission characteristics. Adjust the engine speed at 1100 rpm by means of the engine tachometer and digital tachometer, and reduce the load gradually until the engine speed increased to 1900 rpm automatically by increments of 200 rpm. The BSFC for B20 It seems less than the other ratio of biodiesel blends, and the BTE of biodiesel blends is lower than the pure diesel but the B20 having high BTE in comparison with the other biodiesel- diesel mixtures. the UHC and CO emission for B20 is less than the biodiesel blends and pure diesel, but the NOX emission for B20 is lower than the other biodiesel blends and higher than pure diesel. The present work shows the B20 relatively is a better performance and combustion characteristic than that biodiesel blends ratio.

Numerical comparison of combustion characteristics and cost between hydrogen, oxygen and their combinations addition on natural gas fueled HCCI engine

Hydrogen, oxygen, and their combinations as effective species in the production of radical OH, which plays an effective role in the HCCI combustion enhancement, are considered to study their effect on combustion characteristics and resolving the challenges facing natural gas HCCI engines numerically. There are five items were considered for adding oxygen, hydrogen and their compounds, including 1%, 2%,3%, 4% and 5% of the fuel mixture for hydrogen, 10%, 20%, 30%, 40% and 50% for the extra oxygen in oxidizer and add up half of each respectively, including 0.5% H2 + 5%O2, 1% H2 + 10%O2, 1.5% H2 + 15%O2, 2% H2 + 20%O2, and 2.5% H2 + 25%O2. Adding hydrogen to some extent improves the engine efficiency, lowers combustion duration, and brings the engine cycle closer to the ideal Otto cycle and reduces CO and UHC emissions, but it can only increase engine operating range by as much as 4.2% at low load, increases NO emission, and increases the combustion noise. Hydrogen addition results in faster methane combustion, shortens the fuel combustion duration and increases the OH radical concentration. Up to 30%, added oxygen can extend the engine working range up to 48% at low loads, making the engine run smoother and shortening the combustion duration, although IMEP and efficiency decrease, CO and UHC emissions increase. By using hydrogen and oxygen compounds obtained their both benefits simultaneously, the engine operating range expands by 40.19% at low loads, the emissions would be less than the Euro 6 standard limitation and the maximum difference in efficiency is only 2.38% less than hydrogen addition. By adding these additives, ignition delay decreases and SOC advances. Using hydrogen and oxygen to improve engine performance at low loads is an appropriate and affordable solution, which does not cost much.

Emission profiling of a common rail direct injection diesel engine fueled with hydrocarbon fuel extracted from waste high density polyethylene as a partial replacement for diesel with some modifications

A hydrocarbon fuel extracted from waste high-density polyethylene (WHDPE) by catalytic pyrolysis in a batch scale reactor is blended with diesel by 30% vol. (called as D70H30) is tested in a variable compression ratio engine equipped with a common rail system. Experiments were conducted at three compression ratios (16:1, 17.5:1, and 19:1) and exhaust gas re-circulation (EGR) rates (0%, 10%, and 20%) at the engine’s rated power to evaluate its combustion, performance and emission characteristics. The results revealed that, increasing the compression ratio resulted in higher peak cylinder pressure (PCP) and heat release rates (HRR). Introduction of EGR diminished both PCP and HRR peaks. The brake thermal efficiency of D70H30 blend was 4% lower than diesel at same operating conditions which got better at higher compression ratio without EGR. NOx emission was highest when injected at compression ratio 19:1 and at 0% EGR rate which was 6% and 3% higher than diesel and D70H30 blend operated at engine stock settings. In comparison with baseline diesel smoke opacity remained lower at all operating conditions, where lowest smoke emission was recorded at CR19 and at 0% EGR rate. UHC and CO emission followed the similar trend of smoke opacity. Whereas CO2 emission increased with compression ratio and reduced with induction of EGR. It can be concluded from the study that at higher compression ratio and low EGR rates D70H30 blend can be effectively utilized in a CRDi engine.

Influence of molecular structure of oleoresin-derived compounds on flame properties and emissions from laminar flames.

The search for renewable fuels or components which may improve or replace fossil fuels is an important step towards a sustainable future. In particular, the pine oleoresin produced by conifer trees, which is composed by turpentine oil and non-volatile rosin, may be transformed into alternative fuels. In this work, combustion of six molecules which can be obtained from oleoresin either by distillation (i.e., α- and β-pinene) or by further oxyfunctionalization (nopol, terpineol, myrtenol, and borneol) was studied to assess the potential of pine oleoresin as raw material for biofuels. Emission indices of the main pollutants (carbon monoxide-CO, unburned hydrocarbons-UHC, and nitrogen oxides-NOx) were obtained in non-premixed co-flow laminar flames of the oleoresin-derived molecules blended with n-heptane. The main characteristics of the flames (i.e., temperature and height) were also determined. Significant increase in flame temperature and reduction in CO and UHC emissions with respect to n-heptane were observed with nopol, terpineol, and myrtenol, along an increase in NOx emissions, suggesting an improvement in combustion performance. In addition, differences in emission indices, evidenced for these molecules (even between α- and β-pinene), suggest the importance of the molecular structure in the combustion reaction.

Prediction of Pollutants Emissions in a CFM56-3 Combustor, Using Large Eddy Simulation

In the present work a CFD simulation was performed using a CFM56-3 combustor. It was intended to simulate the combustion and emission of pollutants (CO2, CO, UHC and NOx) from the different jet fuels ( Jet A, Jet B and TS-1), when burning these through ICAO’s LTO cycle. Being this a continuity study, the CAD model of CFM56-3 made by Oliveira [5] was used. The mesh was constructed with HELYX-OS software and the numerical study was made using the commercial software ANSYS Fluent16.2. It can be concluded, amongst all the fuels simulated that increasing the power produces higher NOx. There was also an erratic behaviour in the emissions of UHC and CO results, because an empiric model was used and not a detailed chemical model.&#x0D; Keywords: Jet Fuels, ANSYS Fluent, Pollutants emissions, ICAO’s LTO cycle, CFM56-3

Application of composite TNA nanoparticle with bio-ethanol blend on gasoline fueled SI engine at different lambda ratios

In this research, a novel composite nanomaterial is synthesized and blended with gasoline and gasoline-bioethanol in different operational conditions of the engine. The investigated engine is EF7 spark-ignited (SI) that is operated in 25%, 50%, 75%, and 100% under λ = 0.7 and λ = 1.0 at 1400 rpm and 2800 engine speeds. The Ag/Nb co-doped TiO2 (TNA) is emulsified and homogenized with base gasoline and 80% gasoline-20% bioethanol. The results of emission and engine performance are compared with baseline gasoline. The results allow comparing the effect of composite nanoparticle on customary gasoline and blended gasoline-bioethanol at ideal stoichiometric and rich combustion condition. The results indicate that the gasoline-nano application is economic at lower loads (26.76% reduction in BSFC), whereas the gasoline-bioethanol-nano blend at 100% load is the best choice with up to 32.87% save in fuel consumption. Further, the proposed fuel structure with nano addition can decrease the emissions of CO, UHC, NOx, and CO2, while this decrease is more noticeable when the engine is not working ideally at λ = 0.7.

Performance and emission characteristics of a diesel engine fueled with functionalized multi-wall carbon nanotubes (MWCNTs-OH) and diesel–biodiesel–bioethanol blends

Biodiesel is one of the renewable fuels which is similar to diesel fuel. Biodiesel fuel has more oxygen than diesel fuel and this leads to better combustion and thereby, decreases PM, CO, and UHC emissions. On the other hand, biodiesel has a higher viscosity and density than diesel fuel which increases the BSFC, NOx and smoke emissions. One of the ways to solve this problem is using catalysts in the fuel which decreases the viscosity and density of the blend and as a result reduces the smoke and NOx emissions compared to the diesel fuels. Carbon nanotubes are one of the nanoparticles which due to their unique properties such as aspect ratio (length-to-diameter​ ratio), mechanical strength and high thermal and electrical conductivity are considered as a topic of interest by researchers. Due to their hydrophobic surface, carbon nanotubes tend to accumulate. For better dispersion in solution, their surface is amended with different functional groups. In this study, the diesel–biodiesel fuel was prepared with 5% biodiesel and 95% diesel. The MWCNTs-OH with concentrations of 30, 60, and 90 ppm were mixed with bio-ethanol-based solution at concentrations of E4 and E8. The performance and emissions were recorded at the engine speeds of 1800, 2100, and 2400 rpm and full load. The results showed that, addition of the additive to diesel+biodiesel+ethanol blends (B5+E4 and B5+E8) improved the torque and power and decreased the BSFC. The emissions of UHC and CO also decreased but NOx emission increased.

A novel fuel based on biocompatible nanoparticles and ethanol-biodiesel blends to improve diesel engines performance and reduce exhaust emissions

Biodiesel fuel is one of the most important alternative sources that can replace fossil fuels. Biodiesel has many advantages such as high stability, non-toxicity, renewability, high flash point and excellent performance. However, it has disadvantages such as increased NOx emissions, oxidation in air, and incomplete combustion. One of the ways to reduce the negative effects of biodiesel fuel is to use additives such as nanoparticles and catalysts. However, the use of metal oxide and metal nanoparticles poses many environmental hazards. Graphene Quantum Dot (GQD) is one of the newest types of quantum dots that have extraordinary features such as biocompatibility, high thermal conductivity, excellent solubility, low production cost and non-toxicity. Given the potential toxicity of metallic nanoparticles to living organisms, biological nanoparticles such as GQD can be used to solve this problem. In the present study, the performance parameters and emissions of a diesel engine by adding GQD to bioethanol (with 2, 4 and 6%, vol) and biodiesel fuel (B10) at different engine speeds (1800, 2100 and 2400 rpm) was evaluated. The results showed that B10 + E4 + GQD60 was selected as the optimum fuel at all engine speeds since it increased engine power and torque and reduced CO and UHC emissions. In comparison with the pure diesel fuel (D100), the optimal fuel (B10 + E4 + GQD60) increased the engine power and torque for 24.59% and 20.02%. The optimum fuel also decreased CO and UHC emissions by 35.60% and 42.05% compared to the pure diesel fuel (D100).