Smoke Opacity Research Articles

Enhancement of energy, exergy and soot characteristics with the utilization of MEK in diesel engine

This study investigated the effects of methyl ethyl ketone (MEK) on a diesel engine’s energy, exergy and emissions. The evaporation of a bi-component droplet of MEK and heptane was modeled. Furthermore, the soot morphology and nanostructure were quantified. Different blends were examined at other engine conditions. Running the engine under idle conditions and optimum speed considerably reduced engine emissions. MEK noticeably decreased the maximum reachable load of the diesel engine. Both specific fuel consumption and thermal efficiency increased with MEK. The exergetic efficiency increased while the fuel exergy decreased at the same work exergy. The effects of MEK on combustion characteristics were insignificant. However, a stronger premixed combustion phase was obtained where MEK evaporated first and caused a slightly longer droplet lifetime. Low percentages of MEK reduced CO emissions, while NOx emissions increased consistently with the MEK addition. The engine conditions noticeably influenced the unburned hydrocarbon emissions with MEK. Both smoke opacity and primary particle diameter decreased. The fringe analysis emphasized that MEK decreased fringe length, soot intensity, and alignment, increasing fringe tortuosity and spacing. Clearly, methyl ethyl ketone suppressed soot formation in a diesel engine and decreased its reactivity.Graphical abstract

Effect of injection timing on combustion, emission and performance characteristics of safflower methyl ester in CI engine

Biodiesel, as a renewable fuel, holds great promise, yet its high viscosity presents significant challenges when used in diesel engines. To address these challenges, this study delved into the effects of injection timing on the combustion, emissions, and performance of safflower methyl ester (SAME) in a compression ignition (CI) engine. The experimentation involved testing at three different injection timings: the standard 23° BTDC, advanced 27° BTDC, and retarded 19° BTDC. The results yielded valuable insights. Retarded injection timing notably extended ignition delay by 18 % and reduced the heat release rate by 5 % compared to the standard timing, leading to a substantial decrease in NOx emissions by up to 28 %, a 25 % reduction in CO emissions, and a 5 % decrease in smoke opacity. However, it came at the cost of a 10 % reduction in brake thermal efficiency. Conversely, advanced timing increased NOx emissions by 4 % but concurrently lowered smoke opacity by 3 %. This study underscores the critical importance of optimizing injection timing to balance emissions and performance, mainly when dealing with high-viscosity biodiesels like SAME in diesel engines. The results also highlight the potential of SAME as a viable alternative fuel source, provided that injection timing is judiciously managed to account for its unique viscosity and combustion characteristics. In the quest for sustainable energy solutions, such research is pivotal in harnessing the full potential of biodiesel and advancing its integration into the transportation sector.

Synergetic effect of hydrogen supplementation with waste cooking oil biodiesel – An assessment of the emission, combustion and performance parameters of a compression ignition engine

This investigation aims at examine the effects of hydrogen gas at different flow rates in combination with biodiesel made from used cooking oil on the combustion, emissions, and performance parameters of an engine. In order to improve the thermal performance and combustion characteristics of the stationary engine and lower its emissions, hydrogen is injected through the main manifold at varying flow rates ranging from 3 to 9 LPM, and waste cooking oil biodiesel (WCO B20) is injected through the injector as the main fuel. Both of these fuels are used in conjunction with each other. Results of combustion characteristics revealed that the cylinder pressure enhanced by about 7.32 % using 9 LPM hydrogen flow through the main manifold compared to diesel fuel. Similarly, the HRR from the engine using 9 LPM hydrogen flow enhanced by about 9.43 and 13.76 % compared to diesel and WCO B20, respectively. A comparison is made between diesel fuel and with the proposed modified fuel on the engine's performance, which is assessed in terms of BTE and BSFC. For a range of different engine loads, several emission parameters including HC, NOx, CO, CO2, and smoke opacity are monitored and analyzed for the fuel that has been produced. The results showed that the BTE of the engine is higher in the case of WCO B20 with hydrogen fuel in the flow rate of 9 LPM by about 35.38 % at various engine loads in comparison with the other flow rates of hydrogen fuel, WCO B20 blend, and diesel fuel. Similarly, there is a significant decrease in the SFC by about 17.85 % of the fuel using hydrogen fuel at higher flow rates. The CO emissions with WCO B20 biodiesel blend and diesel fuel are higher, whereas there is a substantial reduction in the CO emission about 22.58 % using a higher concentration of hydrogen fuel along with the WCO B20 biodiesel blends. Similarly, the other emissions such as CO2, smoke and HC decrease about 5.38 %, 10.41 % and 5.38 % whereas the NOx formation increases about 7.67 % at peak loads due to a higher rate of combustion.

Upgrading Pyrolysis Bio-Oil through Esterification Process and Assessing the Performance and Emissions of Diesel-Biodiesel-Esterified Pyrolysis Bio-Oil Blends in Direct Injection Diesel Engines.

This research aimed to evaluate the performance and emissions of direct injection diesel engines using blends of diesel-biodiesel-esterified pyrolysis bio-oil (D-B-EPB). The pyrolysis process was employed to produce pyrolysis bio-oil (PBO) from solid biomass obtained from fresh palm fruits. Furthermore, a simple and effective esterification process was used to upgrade the PBO. The methyl ester (ME) purity of EPB production was studied to optimize three independent variables: methanol (14.8-65.2 wt %), sulfuric acid (1.6-18.4 wt %), and reaction time (16-84 min) using the response surface methodology. The actual experiment yielded a ME purity of 72.73 wt % under the recommended conditions of 40.3 wt % methanol, 13.0 wt % sulfuric acid, 50 min reaction time, 60 °C reaction temperature, and 300 rpm stirrer speed. Additionally, the stability and phase behaviors of D-B-EPB blends were analyzed by using a ternary phase diagram to determine the potential blending proportion. The results revealed that a fuel blend consisting of 30 wt % diesel, 60 wt % biodiesel, and 10 wt % EPB (D30B60EPB10) met the density and viscosity requirements of diesel standards. This D30B60EPB10 blend was subjected to performance and emission tests in diesel engines at various speeds ranging from 1100 to 2300 rpm and different engine loads of 25, 50, and 75%. In terms of performance analysis, the brake thermal efficiencies of biodiesel and D30B60EPB10 were 7.19 and 3.88% higher than that of diesel, respectively. However, the brake-specific fuel consumption of the D30B60EPB10 blend was 6.60% higher than that of diesel due to its higher density and viscosity and lower heating value compared with that of diesel. In the emission analysis, the D30B60EPB10 blend exhibited performance comparable to diesel while being more environmentally friendly, reducing carbon monoxide, carbon dioxide, nitrogen oxide, and smoke opacity by 8.73, 30.13, 37.55, and 59.75%, respectively. The results of this study suggest that the D-B-EPB blend has the potential to serve as a viable biofuel option, reducing the proportion of diesel in blended fuel and benefiting farmers and rural communities..

Study of the effects of bio-silica nanoparticle additives on the performance, combustion, and emission characteristics of biodiesel produced from waste fat

Numerous countries are investigating alternative fuel sources in response to the escalating issue of energy inadequacy. Using environmentally sustainable biodiesel as a potential alternative to fossil fuels, particularly from waste sources, is a developing prospect. This study aims to examine the feasibility of utilizing industry leather waste as a diesel fuel substitute. Traditional transesterification was used to obtain methyl ester out of leather waste. After processing, 81.93% of methyl ester was produced. Bio-silica (Bio-Si) is used as a fuel additive to enhance combustion and decrease emissions. This work utilized a leather industry waste fat biodiesel (LIWFB), LIWFB blend (B50), LIWFB blend with Bio-Si nanoparticles (B50Bio-Si50, B50Bio-Si75, and B50Bio-Si100 ppm) to analyze the engine outcome parameters at standard operating conditions. Experimental results revealed that adding Bio-Si in the biodiesel blend increased thermal brake efficiency (BTE) but was lower in diesel fuel. The biodiesel blends reduced NOx emissions more than Bio-Si nanoparticle blends. Furthermore, the smoke opacity was reduced by 31.87%, hydrocarbon (HC) emissions were reduced by 34.14%, carbon monoxide (CO) emissions were decreased by 43.97%, and oxides of nitrogen (NOx) emissions were slightly increased by 4.45% for B50Bio-Si100 blend compared to neat diesel. This investigation determined that all the emissions remained lower for all combinations than neat diesel, with a small increase in NOx emissions. Therefore, the LIWFB blend with Bio-Si nanoparticles was a viable diesel fuel alternative in diesel engines.

Effects of using a novel fuel vaporizer on partially premixed charge compression ignition (PPCCI) engine emissions, performance, and combustion characteristics

Environmental concerns of toxic emissions and depleting of fossil fuel supplies due to their excessive usage as the main source of energy have raised interests in the creation of novel combustion modes that result in reduction of combustion temperatures and produce low emissions. In comparison to conventional diesel engines, the partially pre-mixed charged compression ignition (PPCCI) combustion strategy has demonstrated its ability to significantly reduce emissions carbon monoxide (CO), unburned hydrocarbon (HC), oxides of nitrogen (NOX), carbon dioxide (CO2) and smoke opacity. In order to compare the results with those of conventional engines, the current experimental work’s objective is to investigate the combustion, performance, and exhaust emissions characteristics of PPCCI engines. A single-cylinder, air-cooled, 4-stroke, direct-injection diesel engine that had been modified to run in PPCCI mode was used for the experiments. An external mixture formation technique with a fuel vaporizer is added to create the homogeneous mixture for PPCCI combustion. After being heated to the point of vaporization, liquid diesel fuel vapor was mixed with some fresh air and then the mixture directed to the intake manifold, where it was mixed with the remaining fresh air to create an external homogenous mixture that filled the combustion chamber. The tests were conducted at different premixed ratios of diesel fuel proportions of 15%, 20%, and 30% in the intake port. However, the fuel vaporizer chamber was kept at fixed temperature of 100 °C, 105 °C, 110 °C, 115 °C, and 120 °C. The PPCCI engine results were compared with the conventional engine data. Results from the PCCI technique at various premixed ratios indicate a certain decrement for HC, CO, NOX, and smoke emissions, rising in BTE “brake thermal efficiency”. At 30% premixed ratio of the fuel vapour inducted at 110 °C in PCCI mode give the best results as the brake thermal efficiency raised from 28.8% for CDC mode to 34.2% for PCCI mode at full load. Additionally, NOX emissions decreased from 615 PPM to 550 PPM, HC emission decreased to 30 PPM, CO emission decreased from 0.09% to 0.06% and a decrease in smoke opacity from 38% to 19.3%.

Performance and emission characteristics of a diesel engine fuelled by biodiesel from black soldier fly larvae: Effects of synthesizing catalysts with citric acid

Biodiesel has several environmental benefits, such as biodegradability, renewability and lower soot emissions. However, biodiesel has undesirable properties such as higher viscosity and density and low calorific value compared to petroleum diesel, resulting in high Brake Specific Fuel Consumption (BSFC), reduced Brake Power (BP) and increased NOX emissions creating an environmental concerns in biodiesel development. This study investigated the effects of synthesizing transesterification catalysts (CaO and NaOH) with Citric Acid (CA) on the quality of biodiesel and biodiesel blends produced from Black Soldier Fly Larvae (BSFL) (Hermetia Illucens). The quality of biodiesel and blends was determined based on fuel properties, engine performance and emission composition characteristics. The tests were performed on a single-cylinder, four-stroke, Compression Ignition (CI) diesel engine at five loads at a constant speed of 1500 rpm. The results showed that synthesizing the catalysts with CA significantly affected the fatty acid profile of the biodiesel compared to physical fuel properties. B100 (pure BSFL biodiesel) exhibited higher BSFC by 10.57–13.97 % and lower BP by 4.21–7.83 % than diesel fuel. However, the Brake Thermal Efficiency (BTE) of biodiesel was higher than that of diesel fuel by 0.82–4.34 % at maximum load. Synthesizing catalysts with CA improved the viscosity of biodiesel by 0.93–2.81 % and effectively reduced NOX, HC and Smoke opacity by 2.23–3.16 %, 4.95–5.83 % and 20.51–41.15 %, respectively.

Biomass pyrolysis oil/diesel blends for a small agricultural engine

The present study reports on an investigation of teak sawdust pyrolysis oil blended with commercial diesel in a small four-stroke compression ignited engine. The engine performance and emissions were evaluated. The teak sawdust pyrolysis oil was obtained from a single-stage fixed bed pyrolysis reactor at 600 °C. Its physicochemical properties were characterized and found to be acceptable for the engine. Teak sawdust pyrolysis oil blends with diesel at the ratios of 10%, 25%, and 50% by mass were utilized. The small engine was tested at constant speeds from 800 to 2600 r/min. 25% teak sawdust pyrolysis oil blend at 2000 r/min was found to have better brake thermal efficiency with lower brake-specific fuel consumption compared to the other teak sawdust pyrolysis oil blends. Meanwhile, the highest engine load was obtained at 50% teak sawdust pyrolysis oil blend and 2600 r/min to be 8 kW. Furthermore, the emissions of CO, CO2, and hydrocarbon at 50% teak sawdust pyrolysis oil and 2000 r/min were slightly lower than other teak sawdust pyrolysis oil blends, no NOx detection in tested fuels, moreover, at 2600 speed, the smoke opacities of the fuels show lower than those the others. It was noted that a blend of 25% teak sawdust pyrolysis oil with diesel was suitable for the small engine (at 2000 r/min) in terms of performance and CO, CO2, and NOX emission for sustainability in agriculture and rural areas.

Effect of nanoparticles (Al2O3 and CeO2) blended with biodiesel on combustion, performance, and emissions of a diesel engine

The increase in the utilization of fossil fuels in almost all the energy production sector badly impacts the environment because of incomplete combustion. The incomplete combustion of fuels releases soot, unburned hydrocarbon, and greenhouse gas emissions, contributing significantly to climate change. In the current experimental work, the evaluation of the effect of the addition of aluminium oxide (Al2O3) and cerium oxide (CeO2) nanoparticles in Jatropha biodiesel (B20) has been performed on the combustion, performance, and emission characteristics of compression ignition engine. These nanoparticles have been added because they have a large surface area-to-volume ratio. The air-fuel mixture and the evaporation rate are enhanced, leading to improved burning. The increase in brake thermal efficiency has been observed with nanoparticles blended fuel, i.e. (B20 + 30 ppm Al2O3 + 30 ppm CeO2) by 9.354%. In contrast, drop-in oxides of nitrogen, carbon monoxide, HC, and smoke opacity emissions were observed by 24.67%, 33.33%, 23.08%, and 34.01%, respectively, compared with pure biodiesel. Using nanoparticles in Jatropha methyl ester reduces ignition delay, increases combustion duration, and starts earlier combustion, reducing heat release rate, cylinder pressure, and pressure rise rate by 10.53, 1.994, and 3.687%, respectively, as compared to the B20 blend.

Experimental Evaluation of CNG Substitution Ratio on Exhaust Gas Emissions of Diesel/CNG Dual Fuel Combustion

The addition of Compressed natural gas as a complement to diesel in compression ignition engines in dual-fuel combustion mode is a viable technology for increasing efficiency and lowering emissions. This work investigates the impact of a dual-fuel operating mode on the engine exhaust pollutant emissions of a diesel engine using compressed natural gas as the principal fuel and neat diesel as the pilot fuel. Compressed natural gas was injected into an intake manifold of a single-cylinder diesel test engine under different engine operating parameters, and up to 80% substitution was attained. And diesel fuel was injected after the compressed natural gas air mixture was compressed. The tests were carried out at five different compression ratios ranging from 13:1 to 15:1 in steps of 0.5:1. The experiment study revealed that injecting CNG into diesel engines via dual fuel combustion significantly impacted exhaust gas emissions compared to pure diesel combustion. The Carbon monoxide (CO) and hydrocarbon (HC) emissions were increased, while carbon dioxide (CO2), nitrogen oxide (NOX) and smoke opacity were decreased in dual fuel combustion compared to single diesel fuel.

Enhancing performance characteristics of biodiesel-alcohol/diesel blends with hydrogen and graphene nanoplatelets in a diesel engine

The pursuit of ecologically friendly and sustainable energy solutions is currently at the forefront of scientific study and technological advancements. The replacement of fossil fuels is a serious challenge in diesel engines. Furthermore, several researchers are concerned about lower-rate hydrogen enrichment and NOx emissions. In the current study, 50 mg/l of graphene nanoplatelets (G) and 10% of n-Butanol are used as additives in sterculia foetida biodiesel-diesel blends, along with H2 supply (at a flow rate of 3 and 6 lpm) as a secondary fuel, to improve the overall performance and reduce emissions of a single-cylinder, four-stroke, compression ignition engine. The combination of 20% biodiesel is blended in 80% diesel (B20), 50 mg/l of G included B20 (B20G50), 10 vol % of n-Butanol (on a volume basis) added in B20G50 blend (B20G50+n-Bu10) are used as piloted fuel. Besides, hydrogen enriched with air as a secondary fuel and B20G50+n-Bu10 fuel blend supplied as piloted fuel (B20G50+n-Bu10+3H2, and B20G50+n-Bu10%+6H2) are fueled to determine the performance, combustion, and emission characteristics of a CI engine. The addition of G and n-butanol in a B20 blend with a higher flow rate of H2 enrichment improved performance (Brake thermal efficiency increased by 7.54%, and Brake specific fuel consumption decreased by 20.75%). In contrast, the combustion parameters such as cylinder pressure and Heat release rate are improved by 9.8 and 6.23% at 100% load for the same blend. In contrast, emission characteristics of Carbon monoxide, Hydrocarbons, and smoke opacity are lowered by 19.75, 24.86, 9.58, and 8.8%, respectively, at higher loads as compared to the B20 blend. The higher heating value, improved atomization characteristics, superior flame velocity of H2, greater thermal diffusivity, the catalytic effect of nanoplatelets, and higher oxygen level of n-butanol improved engine performance, combustion, and decreased emission characteristics on diesel engines with no engine modifications. The outcomes of this research may be beneficial to run stationary engines used in various industrial sectors.

The combined effect of hydrogen enrichment and exhaust gas recirculation on the combustion stability, performance and emissions of CI engine energized by algae biodiesel

The scarcity of fossil fuels, the rising cost of liquid fuels, and the wide pollution footprint of conventional fuels all motivate scientists to seek out new approaches. This experimental study aims to explore the performance and emissions of compression ignition (CI) engines by introducing hydrogen into a biodiesel blend derived from algae. According to this study, the superior thermal properties of hydrogen associated with algal biodiesel have a significant impact on the performance and emissions of dual-fuel engines. The effect of hydrogen substitution rates of 10.4, 21.6, 32.4, 43.2, and 54 g per hour (g/h) on pure algae biodiesel was investigated. In comparison to diesel, the algae biodiesel reduces unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions by 4.1% and 8.82%, respectively, while nitrogen oxide (NOx) emissions increase by 18%. Diesel was found to have increased brake thermal efficiency (BTE) and decreased brake specific energy consumption (BSEC) compared to biodiesel. With the addition of pure biodiesel, the 43.2 g/h H2 substitution rate produces a maximum thermal efficiency of 1.92% and a 9.5% decrease in brake-specific energy consumption compared to diesel at maximum load. Compared to diesel, the emission attributes of UHC, CO, and smoke opacity decreased by about 45%, 48%, and 41%, respectively. However, NOx emissions increase by about 36% compared to diesel due to the higher flame temperature and carbon-free fuel of hydrogen and oxygenated biodiesel. The induction of 15% exhaust gas with B100 + 43.2 g/h H2 reduces NOx by about 31% in comparison to B100 + 43.2 g/h H2 without exhaust gas recirculation (EGR). This is primarily attributable to the high oxygen dilution and specific heat capacity of burned gases, which result in a decrease in peak cycle temperature. Compared to diesel, B100 + 43.2 g/h H2 increased the cylinder pressure and heat release rate by about 1.86 and 4.29%, respectively. As a result of its high energy density, hydrogen improves overall energy utilization and engine performance. Hydrogen's rapid flame speed and wide flammability range contribute to the efficient and complete combustion of the algae fueling the CI engine. As well as showing outstanding performance, dual fuel CI engines have the potential to significantly contribute to lowering emissions. Finally, it was determined that using algae biodiesel and exhaust gas recirculation with hydrogen substitution in diesel engines can significantly reduce emissions while increasing efficiency.

Ozone-assisted combustion and emission control in RCCI engines: A comprehensive study

This paper presents an investigation into the combustion and emission characteristics of reactivity-controlled compression ignition (RCCI) engines using ozone seeding, which is known as one of the most highly oxidizing chemical species. The study aims to address challenges pertaining to combustion control and emissions deterioration. Therefore, the current work investigates the RCCI mode of operation in a single-cylinder diesel engine with intake air that has been seeded with ozone by introducing conventional diesel fuel as a high-reactivity fuel using a high-pressure direct injection method and iso-octane as a low reactivity fuel using a low-pressure port injection method. In the experimental study, different ozone concentrations up to 300 ppm and three different energy-based premixed ratios of low reactivity fuel from 0% to 45% with a 15% rise rate were examined under various engine loads and constant engine speed. The methodology used in this research provided for simultaneous decreases in unburned hydrocarbon (HC) emissions and smoke opacity for RCCI engines. According to the experimental findings, simultaneous utilization of RCCI mode and ozone seeding led to a decrease of up to 36% in HC emissions and a reduction of up to 98.7% in smoke opacity. Moreover, nitrogen oxides (NOx) emissions were reduced by up to 39.5% at 20% engine load, whereas carbon monoxide (CO) emissions exhibited a decrease of up to 46% at 60% load. The RCCI mode also yields significant reductions in pollutant emissions and notable increases in brake thermal efficiency (BTE) when compared to the conventional diesel mode (CDM). In conclusion, this experimental study presents a promising solution for addressing emissions deterioration in RCCI engines while simultaneously achieving reductions in pollutant emissions.

Investigation of the effect of adding carbon nanotubes, lower and higher level alcohol additives, in Yellow oleander methyl ester-diesel blend on diesel engine performance

ABSTRACT The current study is to determine the overall performance of a compression ignition engine (CI) employing a B30 (30% Yellow Oleander Methyl Ester (YOME) and 70% diesel) sample including nano and alcohol additives. Initially, the surface-modified carbon nanotubes (CNTs) (at a dosage of 60 mg/L) are sonicated in the B30 blend for 30 mins at 40 kHz and termed B30CNTs60. It was found to be quite stable as evidenced by characterization. The B30CNTs60 blend is then blended with a fixed volume (10%) of n-Butanol, iso-Butanol, and Dimethyl Carbonate (DMC), and referred to as B30CNTs60+n-Butanol10%, B30CNTs60+iso-Butanol10%, and B30CNTs60+DMC 10%. The physicochemical properties of all fuel samples met ASTM criteria and samples were experimented on a 1-cylinder, 4-stroke diesel engine under varying loads. The results revealed that the B30CNTs60+DMC 10% blend enhanced heat release rate (HRR), cylinder pressure (CP), and brake thermal efficiency (BTE) by 11.2%, 8.64%, and 11.92%, respectively. Furthermore, with B30CNTs60+DMC 10% blend, the combustion duration, brake specific fuel consumption (BSFC), carbon monoxide (CO), hydrocarbons (HC), carbon dioxide (CO2), nitrogen oxide (NOx), and smoke opacity were reduced by 10.9%, 15.62%, 18.24%, 18.78%, 8.12%, 6.75%, and 10.92% respectively. Finally, the B30CNTs60+DMC 10% blend was suggested to use in CI engines.

Biyoyakıt-dizel karışımı ile çalışan stasyoner dizel motorunun performans ve emisyonlarını iyileştirmek için titanyum dioksit nanopartiküllerinin kullanılması

In this research, the potential effects of titanium dioxide (TiO2) nanoparticles on improving a stationary diesel engine characteristic fuelled with a biofuel mixture-diesel blend (B25: 25% vol. biofuel mixture containing biodiesel, waste cooking oil and ethanol + 75% vol. diesel) are experimentally investigated. TiO2 nanoparticles are dispersed in B25 fuel at 50, 100, and 150 ppm concentrations. Subsequently, they are tested in a stationary research diesel engine at a rotational speed of 1500 rpm and specific loads. Nanoparticles enhance combustion, offering increased cylinder gas pressure, net heat release rate, and reduced ignition delay period and combustion duration. The engine performance is enhanced more with increasing nanoparticle concentration. TiO2 nanoparticles with a 150 ppm rate reduce brake-specific fuel consumption by 3.21% and increase the brake effective efficiency by 3.67%, on average, compared to B25 fuel without nanoparticles. CO emission and smoke opacity are reduced by up to 31.89% and 24.56% with TiO2 nanoparticles. However, under the same operating conditions, NO emission increases to 30.58% compared to sole B25. Nevertheless, the NO emission of nanofuels is still less than that of diesel fuel. This study's results indicate that using TiO2 nanoparticles as a nano fuel additive can enhance the stationary engine's operation fueled with the biofuel mixture-diesel blend. Keywords: Biofuel, Diesel engine, Fuel additive, Nanoparticles

Impact of water content in fuel for smoke opacity

The development of internal combustion engines is focused at solving problems like: fulfillment with increasingly stringent requirements regarding exhaust emissions and elimination of threats to the natural environment. The subject of this thesis is to assessment the impact of supplying a compression-ignition engine with hydrocarbon mixtures and to examine the impact of water on external parameters of the engine, such as smoke opacity. The tests were carried out using a innovative mixture of hydrated fusel oils, ethyl alcohol and ionic and/or non-ionic emulsifiers, from which was made of microemulsions with a water content in diesel oil of 5, 10, 15, 20 and 25%. The main tests were carried out on a 4-cylinder VW 1.9 TDI internal combustion engine at a constant engine crankshaft speed of 3000 rpm and variable load of 0, 30, 60, 90, 120, 150 and 180 Nm. The tests carried out showed a beneficial effect of the water content in the diesel oil on the reduction of the average value of smoke opacity, which systematically decreases with the increase in the percentage of water in the diesel oil.

Experimental study on fuel consumption and smoke opacity of defective coffee-bean-based biodiesel fuel engines

This experimental study aims to analyse the performance of sorted coffee beans-based biodiesel. This study is carried out in three main stages; (a) the preparation process of coffee beans raw material, (b) the biodiesel formation process, and (c) biodiesel performance analysis. In manufacturing process, the coffee bean powder is added with two chemical treatments sequentially; extraction-distillation and esterification/transesterification. Parameters of analysis in this study are the characteristics of the biodiesel and the performance of the biodiesel-diesel mixture in terms of fuel consumption efficiency and engine smoke opacity. Measurements of Engine Running Time (ERT) and smoke opacity were carried out on a single-piston diesel engine. There were five biodiesel-diesel mixture specimens; B0, B5, B10, B15, and B20 (20% biodiesel fraction). The experimental results show that mixing biodiesel with diesel fuel provides two main advantages; extending engine running time which means fuel consumption efficiency, and lowering the smoke opacity level. Therefore, it is more environmentally friendly. The efficiency of fuel consumption and smoke opacity depends on the biodiesel fraction in the fuel mixture. The results and methodology of this research are expected to be an additional reference in the development of biodiesel as an alternative fuel.

Effect of Diethyl Ether on the Performance and Emission Characteristics of a Diesel Engine Fueled with a Light Fraction of Waste Cooking Oil

In this study, a diesel engine was used to operate with blends of light fraction waste cooking oil (LFWCO) with diethyl ether (DEE). DEE was blended as an additive in the 5% to 20% ratio in steps of 5% each. The test indicates that LFWCO+15-DEE produced optimum results regarding performance and emission. The BSFC for LFWCO+15-DEE was found to be higher by about 28.9%, and the BTE was lower by about 7.6%, in contrast to diesel, at 100% operating load, respectively. For LFWCO+15-DEE the EGT was lower by about 11.9%, in contrast to neat diesel, at 100% operating load. The various emissions such as carbon monoxide (CO), nitrous oxide (NO), and smoke opacity for LFWCO+15-DEE were found to be lower by about 32.9%, 25%, and 29.4%, but the NO release was more than other blends and it was about 36%, in contrast to diesel at 100% operating load, respectively.

Ultra-low soot/ particulate emissions from a dimethyl ether-fueled agricultural tractor engine

This study eveluates using dimethyl ether (DME) fuelled engine for marching towards zero soot and particulate matter (PM) emissions in the agricultural sector. Comparative emissions and particulate characteristics were analysed for a customised DME-fuelled engine and an unmodified baseline diesel engine. The experimental investigations were performed on a multi-cylinder tractor engine using a dedicated DME fuel injection equipment (FIE) and an unmodified diesel FIE. Regulated emissions, namely carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx), smoke opacity, and particulates were measured at three engine speeds (1200, 1600 and 2000 rpm) and five loads (1.29, 2.59, 3.88, 5.18, and 6.47 bar BMEP). The static fuel injection timing for both test fuels was maintained constant; however, the actual injection timing could be slightly different for both test fuels because of their different physicochemical properties. DME-fuelled engine exhibited relatively higher HC and CO emissions than diesel at low loads; however, both test fuels exhibited nearly identical emissions at higher loads. NOx emissions were lower for DME-fuelled engine than baseline diesel, and its smoke opacity was also negligible at all engine loads and speeds. The particulate number concentration for DME-fuelled engines was much lower than baseline diesel at all test conditions, except 1.29 bar BMEP. Particulate emissions from DME-fuelled engine were mainly in the form of nanoparticles and nucleation mode particles, with negligible numbers of accumulation mode particles. This experimental study demonstrated that DME-fuelling of the tractor engine reduced emissions and it can be used as a sustainable and greener fuel to develop cleaner engines for agriculture/ transport sectors.

Investigation on Ammonia-Biodiesel Fueled RCCI Combustion Engine Using a Split Injection Strategy.

Advanced combustion concepts in compression ignition are emerging as one of the most promising solutions to reduce nitrogen oxides (NOx) and particle emissions without sacrificing fuel efficiency. Among many advanced combustion concepts, reactive controlled compression ignition (RCCI) can achieve a wider working range. In this study, to implement RCCI operation, ammonia gas is introduced through the manifold as a low-reactive fuel, and biodiesel is injected directly as a high-reactivity fuel with a 40:60 energy ratio. The effect of biodiesel split ratio in a split injection strategy (pre- and main injections) is examined under varied load conditions, and the results are compared with ammonia/biodiesel single injection. Results indicate that the use of the 45% biodiesel split ratio at full load boosts the peak in-cylinder pressure and heat release rate and shifts the peak occurrence toward the top dead center (TDC). An increase in brake thermal efficiency (BTE) to 36.22% and reduced brake specific energy consumption (BSEC) to 8.75 MJ/kWh are 12.33% higher and 19.31% lower than ammonia/biodiesel single injection. Emissions of HC, CO, and smoke opacity were reduced to 50 ppm, 0.098% vol, and 15.6%, which are 34.21, 39.13, and 33.89% lower, while the emission of NOx was increased to 615 ppm, which is 36.06% higher than the single-injection ammonia/biodiesel RCCI combustion.