Unburnt Hydrocarbon Emissions Research Articles

Influence of injection timing variation on combustion-emission-performance aspects of emulsified plastic oil-run compression ignition engine

Abstract This study investigates the influence of injection timing (IT) on combustion-emission-performance aspects of the compression ignition (CI) engine, running with emulsified plastic oil (EPO). The IT was advanced (250 bTDC) as well as retarded (210 bTDC) for EPO run engine, and the obtained results were compared with EPO and neat diesel run engine at standard IT (230 bTDC). At full load, the peak cylinder pressure increased to 64.7 bar when the IT was advanced to 250 bTDC. The corresponding peak heat release rate also increased to 40.29 J/CA due to the advancement of IT in comparison with the standard IT. The brake-specific fuel consumption (BSFC) also improved at all loading conditions. However, the advancement of IT increased the nitrogen oxides (NOx), and temperature of exhaust gas slightly. In addition, 250 bTDC for EPO also reduced the unburnt hydrocarbon (HC), carbon monoxide (CO), and smoke emissions w.r.t the standard IT. Largely, the advanced IT improved the majority of the engine characteristics for EPO except for the NOx, but that is also lower than diesel-run operation. Thus, 250 bTDC (for EPO) exhibits promising potential to be implemented in CI engines.

Enhancing the Efficiency of Rotary Thermal Propulsion Systems

Transport electrification is essential for reducing CO2 emissions, and technologies such as hybrid and range-extended electric vehicles will play a crucial transitional role. Such vehicles employ an internal combustion engine for on-board chemical energy conversion. The Wankel rotary engine should be an excellent candidate for this purpose, offering a high power-to-weight ratio, simplicity, compactness, perfect balance, and low cost. Until recently, however, it has not been in production in the automotive market, due, in part, to relatively low combustion efficiency and high fuel consumption and unburnt hydrocarbon emissions, which can be traced to constraints on flame speed, an elongated combustion chamber, and relatively low compression ratios. This work used large eddy simulations to study the in-chamber flow in a peripherally ported 225cc Wankel rotary engine, providing insight into these limitations. Flow structures created during the intake phase play a key role in turbulence production but the presence of the pinch point inherent to Wankel engine combustion chambers inhibits flame propagation. Two efficiency-enhancement technologies are introduced as disruptive solutions: (i) pre-chamber jet ignition and (ii) a two-stage rotary engine. These concepts overcome the traditional efficiency limitations and show that the Wankel rotary engine design can be further enhanced for its role as a range extender in electrified vehicles.

Evaluation of the Productivity and Potential Utilization of Artemisia dubia Plant Biomass for Energy Conversion.

Field studies with the large-stemmed plant Artemisia dubia (A. dubia) have been carried out at the Vėžaičiai Branch of LAMMC since 2018. According to three years of experimental results, annual dry matter (DM) yield varied from 7.94 to 10.14 t ha-1. Growing conditions, nitrogen application level, and harvesting time had statistically significant impacts on A. dubia productivity. The most important tasks of this article were to investigate and determine the factors influencing A. dubia plant biomass productivity and the evaluation of technological, power, and environmental parameters of plant biomass utilization for energy conversion and the production of high-quality solid biofuel pellets. For the experiments, six variants of A. dubia samples were used, which were grown in 2021. Plants were cut three times and two fertilization options were used: (1) no fertilization and (2) fertilization with 180 kg ha-1 of nitrogen fertilizer. These harvested plants were chopped, milled, and pressed into pellets. The physical-mechanical characteristics (moisture content, density, and strength) of the A. dubia pellets were investigated. During this study, it was found that the density in the dry mass (DM) of the pellets ranged from 1119.86 to 1192.44 kg m-3. The pellet moisture content ranged from 8.80 to 10.49%. After testing pellet strength, it was found that the pellets which were made from plant biomass PK-1-1 (first harvest without N fertilization) were the most resistant to compression, and they withstood 560.36 N of pressure. The dry fuel lower heating value (LHV) of the pellets was sufficiently high and was very close to that of the pine sawdust pellets; it varied from 17.46 ± 0.25 MJ kg-1 to 18.14 ± 0.28 MJ kg-1. The ash content of the burned pellets ranged from 3.62 ± 0.02% to 6.47 ± 0.09%. Emissions of harmful pollutants-CO2, CO, NOx, and unburnt hydrocarbons (CxHy)-did not exceed the maximum permissible levels. Summarizing the results for the investigated properties of the combustion and emissions of the A. dubia pellets, it can be concluded that this biofuel can be used for the production of pressed biofuel, and it is characterized by sufficiently high quality, efficient combustion, and permissible emissions to the environment.

Experimental investigation on diesel engine operating with CuO nanoparticles dispersed Azadirachta indica biodiesel

This study aims to ascertain the operating parameters of a Copper oxide nanoparticle and Azadirachta indica biodiesel-powered diesel engine. Copper oxide nanoparticles were considered at 75 ppm, and three dispersants were added at the same ratio as nanoparticles. An ultrasonic bath sonicator was used to sonicate the nanoparticles, and later, the ultrasonicator was used to prepare the nanofuel. The experiment was conducted on a diesel engine with different injection timings, such as 21 °bTDC, 23 °bTDC, and 25 °bTDC at full load. The performance was slightly improved by mixing nanoparticles with B20, and it got even better by adding dispersants. The combustion parameters were also changed compared to diesel. Finally, the emissions of carbon monoxide, unburnt hydrocarbons, nitrogen oxides and smoke opacity were significantly reduced by the dispersion of nanoparticles. Increasing the injection timing also led to better results, and 25 °bTDC showed better results. The B20+CuO75+QPAN 75 has shown the most remarkable effects among other samples. At 25°bTDC, the brake thermal efficiency, brake specific fuel consumption, cylinder pressure, net heat release rate, were 35.03 %, 0.391 kg/kWh, 66.23 bar, and 89.39 J/°CA, respectively, while carbon monoxide, unburnt hydro carbons, smoke, and oxides of nitrogen were 0.089 %, 32 ppm, 19.351 %, and 1238 ppm.

Effects of fuel injection pressure and quantity on low octane gasoline sprays in a simulated high-pressure ambient environment of a gasoline compression ignition engine

Gasoline Compression Ignition technology using low-octane gasoline-like fuel can lead to very low NOx and Soot emissions and enhanced thermal efficiency than conventional diesel engines. The difference in test fuel properties is a significant reason for the difference in the fuel–air mixture formation in Gasoline Compression Ignition engines offering these advantages. In this study, microscopic and macroscopic spray characterisation of baseline diesel, 50 % v/v diesel blended with 50 % v/v gasoline (G50), and 20 % v/v diesel blended with 80 % v/v gasoline (G80) are conducted in a high-pressure ambient environment relevant to Gasoline Compression Ignition engines. The study was performed in a constant volume spray chamber in non-reacting conditions using Phase Doppler Interferometry and Diffused Backlit Illumination techniques. The test fuels were injected into a 30 bar ambient pressure environment at 400, 500, and 700-bar fuel injection pressures. The liquid spray penetration length of gasoline-diesel blends was slightly shorter than baseline diesel, but their spray cone angles and entrained air mass were significantly higher. The average axial droplet velocity was higher, and the Sauter Mean Diameter was lower for gasoline-diesel blends than baseline diesel 40 mm away from the injector nozzle exit, indicating superior mixture formation for the gasoline-diesel blends. The effect of droplet collision and injected fuel quantity on droplet size distribution was assessed in all test fuels. Droplet collisions increased the Sauter mean diameter of the spray at farther distances. Smaller fuel injection quantities decreased the Sauter mean diameter of the spray, increasing the probability of unburnt hydrocarbon emission producing ultra-lean regions in the engine combustion chamber.

ENHANCING PERFORMANCE OF BIODIESEL-HYDROGEN BLENDS OPERATED DI DIESEL ENGINE USING VARIABLE INJECTION TIMING

The study aimed to investigate the effect of injection timing (IT) on the combustion, emission, and performance characteristics of a single-cylinder, four-stroke, direct injection (DI) diesel engine. The engine was run on different fuel blends, namely, pure diesel, diesel blended with 20% mahua oil methyl ester (B20) with three hydrogen flow rates of 20, 22.5, and 25 liters per minute (lpm). The experiment was carried out at a rated speed of 2000 rpm. Four different injection timings (ITs) were applied, namely, 19°, 23°, 27°, and 31° bottom top dead center (BTDC), relative to the standard IT of 23° BTDC. The results showed that the optimal IT was 27° BTDC for B20-hydrogen (22.5 lpm) dual-fuel mode operation. This condition delivered the highest brake thermal efficiency (BTE) between 24.4 and 34.3% , the lowest brake-specific fuel consumption (BSFC) between 0.25 and 0.41 kg/KWh, and the minimum unburnt hydrocarbon (HC) emissions between 8 and 32 ppm, and carbon-monoxide (CO) emissions ranging between 0.002 and 0.389% . However, the concentration of nitrogen-oxides (NOx) emissions was slightly increased, ranging between 24 and 53 ppm compared to B20. Further modifications in the IT resulted in decreased brake thermal efficiency ranging between 13 and 31% , increased hydrocarbon emissions between 25 and 28% , and increased CO emissions between 70 and 96% for both 4° BTDC advancements and retardations. Moreover, both modifications reduced NOx emissions by 8-19% . Hence, based on this study's findings, employing an IT of 27° BTDC for 22.5 Ipm of hydrogen with a B20 dual-fuel mode of operation for the DI diesel engine to achieve optimal performance, combustion, and emission characteristics is recommended.

Effect of graphene oxide nano-particles dispersed biodiesel on combustion, performance and emission characteristics of a diesel engine

Present study aims to investigate the impact of graphene oxide (GO) nano-particles as a fuel additive on the combustion, performance and emission characteristics of a compression ignition engine. The diesel and biodiesel fuels were blended with GO nano-particles at concentrations of 20, 40 and 60 ppm, resulting in the formation of fuel blends named B20GO20, B20GO40 and B20GO60, respectively. During the experiments, several parameters including cylinder pressure, heat release rate, brake-specific fuel consumption, brake thermal efficiency, carbon monoxide (CO), unburnt hydrocarbon, and nitrogen oxide (NOx) emissions were measured. The results showed that the addition of 40 ppm of GO led to a maximum reduction of 36.41% in CO emissions, 17.38% in HC emissions, and 12.56% in NOx emissions. Based on these findings, it can be concluded that biodiesel–diesel blends with GO nano-particles can be utilised as an alternative fuel in diesel engines without requiring significant engine modifications.

Optimization of CI Engine Performance and Emissions Using Alcohol–Biodiesel Blends: A Regression Analysis Approach

This research paper investigates the optimum engine operating parameters, namely engine load, palm biodiesel, and ethanol percentage, by using a regression analysis approach. The study was conducted on a single-cylinder, four-stroke diesel engine at varying engine loads and constant speed. A general full factorial design was established using Minitab software (Version 17) for three different input factors with their varying levels. The test results based on the regression model are used to optimize the engine load and percentages of palm biodiesel and ethanol in diesel–biodiesel–ethanol ternary blends. The analysis of variance (ANOVA) revealed a significant effect on performance and emission parameters for all three factors at a 95% confidence level. From the regression study, optimum brake thermal efficiency (BTE), nitrogen oxide (NOx), carbon monoxide (CO), and unburnt hydrocarbon (UHC) emissions were found to be 12.57%, 436.2 ppm, 0.03 vol.%, and 79.2 ppm, respectively, at 43.43% engine load, 11.06% palm biodiesel, and 5% ethanol share. The findings of this study can be used to optimize engine performance and emission characteristics. The regression analysis approach presented in this study can be used as a tool for future research on optimizing engine performance and emission parameters.

Performance and emission characteristics of a CI engine with post-treated plastic pyrolysis oil and diesel blend

Conversion of waste plastics into energy products is an effective waste management technique as they constitute a considerable portion of solid waste at present. In this study, distilled diesel fraction of Plastic Pyrolysis Oil (PPO) named Distilled Plastic Diesel (DPD) was hydrotreated named hydrotreated plastic diesel (HPD) and blended with commercial diesel fuel by 15:85 ratio (wt%), defined as HPD15, to experimentally investigate the performance and emission characteristics of a compression ignition (CI) engine. The experiment was done in 4-cylinder, 4-stroke diesel engine with an eddy current dynamometer testbed at full load (100 % engine load) and an engine speed of 1200–2400 rpm with 300 rpm intervals. The results are compared with neat diesel fuel data at the same operating conditions. This study found that HPD15 performed better or comparable with diesel fuel. Overall, the brake power (BP) and brake thermal efficiency (BTE) of HPD15 were higher than diesel fuel by a maximum of about 4.77 % and 3.77 %, respectively. Brake specific fuel consumption (BSFC) of HPD15 was lower at all operating speeds (by a maximum of about 4.66 %) and brake specific energy consumption (BSEC) was lower in most of the operating speeds (by a maximum of about 3.77 %). This study also revealed that CO2 at some operating speeds and NOx emission at all operating speeds for HPD15 are lower than diesel fuel. However, CO and unburnt hydrocarbon (UHC) emission are slightly higher for HPD15 than diesel at all speeds. Overall, HPD15 can be recommended as a suitable alternative for diesel fuel without any engine modification.

Analysis of the ion current in misfiring and firing cycles during the cold starting of a compression ignition engine

Compression ignition engines will continue to power heavy-duty, long-haul vehicles, and heavy machinery in the future, while batteries become more prevalent in powering light-duty vehicles. However, compression ignition engines face problems when started under severe cold conditions. These problems include combustion instability, misfiring, and higher emissions of unburnt hydrocarbons. Feedback of an engine’s performance to its control unit can be used to improve the fuel injection strategy in real time and mitigate these problems. The ion current signal, being reflective of the combustion and emissions characteristics, has already been proven as a reliable feedback signal under warmed-up conditions. This paper investigates the ion current signal as potential feedback during the cold starting and the warm-up period. Cold starting experiments were conducted in a VW’s 2.0-L, direct injection, four-cylinder compression ignition engine at ambient temperatures of −10°C, 0°C, 10°C, and 20°C. The engine experienced misfiring cycles at the ambient temperatures of −10°C and 0°C. In some misfiring cycles, the ion current was detected even though the pressure trace did not show a distinct combustion event, indicating that the autoignition occurred but the combustion failed to sustain. This means the ion current can identify un-sustained combustion events in misfiring cycles. In firing cycles, an ion current characteristic could well predict the combustion phasing at ambient temperatures of 10°C and 20°C. The real-time feedback of (1) un-sustained combustion events in misfiring cycles and (2) combustion phasing in firing cycles at various ambient temperatures can be utilized to mitigate cold starting problems in compression ignition engines.

A comprehensive review into the effects of different parameters on the hydrogen‐added HCCI diesel engine

AbstractThe current study presents research investigations and developments related to the homogeneous charge compression ignition (HCCI) engine. Research investigations and recent advances, including the role of various operating conditions on HCCI engine combustion phenomena, emissions, and performance, are discussed. There is growing research interest in investigating HCCI engines with diesel fuel to study combustion, emissions, and performance characteristics due to their association with low NOx emissions. In the published literature, research investigations are also conducted with different fuels ranging from biomass to diesel to gasoline in the HCCI engine showing its capability for utilizing various fuels in coming years. The challenges associated with HCCI combustion are reviewed, and the details of excessive carbon monoxide and unburnt hydrocarbon emissions are discussed. The major parameters affecting the hydrogen addition in HCCI diesel engines are also discussed. Overall, adding hydrogen to a diesel‐fueled HCCI engine improves combustion phasing and can potentially increase thermal efficiency while lowering emissions. In addition, the strength, weaknesses, opportunities, and threat analysis is provided and discussed thoroughly.

Experimental characterization of ammonia, methane, and gasoline fuel mixtures in small scale spark ignited engines

In this study, gaseous anhydrous ammonia is blended with fuels like gasoline and methane and tested in an instrumented, low-technology single cylinder carbureted engine. In-cylinder pressure and emissions are monitored with the various mixtures and their performance is then compared with pure gasoline. With the addition of ammonia, the stability of combustion inside the combustion chamber was affected. But with the addition of a combustion modifier, the overall variability was reduced. At higher substitutions of ammonia, Initial results show an increase in indicated thermal efficiency of the engine. There is also a substantial decrease in the heat release rate (HRR) of the engine when substituting gasoline with ammonia. With the addition of methane, the change in the fuel reactivity helped improve HRR. Increasing ammonia substitution also resulted in an increase in indicated efficiency when compared to pure gasoline by approximately 12% with 50% substitution of ammonia in gasoline. Adding ammonia to the fuel mixtures also showed an initial reduction in unburnt hydrocarbon emission, followed by a sudden increase with further increasing concentration, suggesting incomplete combustion of the fuel mixture. The addition of methane with gasoline also showed a reduction in overall NOx emissions. Furthermore, methane was also tested as the main fuel with ammonia substitution of up to 50%. This ammonia and methane blend also showed comparable results to the gasoline, ammonia, and methane blends tested. From the emissions data, the catalyzing effects of ammonia were also seen with some cases showing varying trends with increasing ammonia substitution. Results from this study can be used to design small-scale engine based power generation systems that need very little modifications to accept ammonia based mixed fuels. Furthermore, this study lays the groundwork for using fuels blends with methane sourced using carbon neutral technologies and ammonia to power engine based systems.

Theoretical investigation of combustion and emissions of CI engines fueled by various blends of depolymerized low-density polythene and diesel with co-solvent additives

The depletion of fossil fuels and the accumulation of plastic waste are both serious issues facing the world today. This study investigated the potential use of plastic waste as an alternative fuel by utilizing diesel (D) to depolymerize low-density polyethylene (LDPE) in the presence of co-solvents. Several co-solvents were examined: a-pinene, toluene, and o-xylene, with ratios of 10% weight in the LDPE/diesel blend. The blends were theoretically tested in a diesel engine to investigate the impact on the combustion characteristics and emissions. According to tested data, the in-cylinder peak pressure and temperature decreased within the blend of D/LDPE in comparison to diesel at all engine loads. However, when co-solvents were added to the D/LDPE blend, in-cylinder pressures increased during the combustion at all loads, with improvements of 0.48%, 0.5%, 0.6%, and 0.4% for the blends of D/LDPE (10% toluene and 1 bar), D/LDPE (10% a-pinene and 1 bar), D/LDPE (10% xylene and 1 bar), and D/LDPE (10% xylene and 10 bar), respectively, in comparison with diesel at 100% load. Co-solvent additions such as a-pinene and o-xylene to the plastic/diesel blend resulted in a substantial and gradual increase in the heat release rate at high loads. In respect to emissions, carbon monoxide, unburnt hydrocarbon, and soot levels were raised by adding LDPE plastic to D and reduced by adding co-solvents. The most effective co-solvents for decreasing carbon monoxide, unburnt hydrocarbon, and soot emissions were pinene, followed by xylene.

Emission Reduction and Performance Enhancement of CI Engine Propelled by Neem Biodiesel-Neem Oil-Decanol-Diesel Blends at High Injection Pressure

Diesel emissions have resulted in air pollution, which is harmful to the sustaining of life. The concerns of energy security and poor air quality have propelled researchers to seek alternate and environment-friendly fuels for the transport sector, keeping diesel engines at the core. Thus, a quaternary blend (diesel-biodiesel-vegetable oil-alcohol) proves to be a promising key to address the above problems. This experimental work focuses aims on investigating the performance and emissions of a diesel engine powered with quaternary blends by changing the fuel injection pressure. The quaternary blend comprised of diesel, neem biodiesel, pure neem oil, and decanol was used to prepare quaternary blends of varied volumetric proportions. This study involves the testing of quaternary blends at varied fuel injection pressure (IP) ranging from 400–500 bar. The engine load varied from 10 Nm to 20 Nm, and the shaft speed was constant at 2000 rpm. It was evident from the outcomes that the least DBODec45 resulted in minimum carbon monoxide (CO) and un-burnt hydrocarbon (UHC) emissions, which were obtained to be 83.33% and 54.5% less than diesel at 500 bar and at a load of 10 Nm and 20 Nm, respectively. Moreover, the blend containing 45% of decanol led to the lowest NOx and smoke concentrations. The lowest brake-specific fuel consumption (BSFC) was achieved at 500 bar and 20 Nm for the same blend and was found to be 3.22% higher than diesel. Moreover, at the same IP and load, DBODec45 led to highest BTE, which was 3.26% lower than pure diesel.

Performance enhancement and emissions reduction in a diesel engine using oleander and croton biodiesel doped with graphene nanoparticles

Biodiesel is considered a suitable substitute for petroleum diesel because it is renewable, environment-friendly, and has a low carbon footprint. However, its high density, high viscosity and low heating value prevents it from replacing petroleum diesel completely. This study investigates the performance and emission characteristics of a compression ignition engine operating on oleander and croton biodiesel doped with graphene nanoparticles. Five fuel samples are used, including diesel (D100), diesel - 80% blended with oleander and croton biodiesel - 20% (OCB20) and OCB20 dosed with graphene nanoparticles at mass fractions of 50 ppm (mg/L), 75 ppm (mg/L) and 100 ppm (mg/L), respectively. The chemical composition of biodiesel and graphene nanoparticles is analyzed using Fourier Transform Infrared (FTIR) spectroscopy while the morphology of the nanoparticles is analyzed using Scanning Electron Microscope (SEM). Engine tests reveal a significant improvement in brake thermal efficiency, especially at 75 ppm concentration which is 2.76% and 18.93% higher than diesel and OCB20, respectively, and a reduction in brake specific fuel consumption by 2.44% and 16.67% compared to diesel and OCB20, respectively. Carbon monoxide (CO) and unburnt hydrocarbon emissions (UHC) decreases for the 50 ppm sample, recording 8.58% and 21.65% reduction in CO and 52.2% and 50% in UHC compared to the diesel and OCB20, respectively. However, Oxides of Nitrogen (NOx) emissions increase. The results indicate that graphene nanoparticle-enhanced biodiesel can adequately substitute petroleum diesel, albeit with NOx reduction techniques.

Feasibility Study of Biofuel Incorporated Nanoparticles as Sustainable IC Engine Fuel: Opportunities and Challenges - An overview

The advent of biofuel as a fossil petroleum substitute has been a revolutionary concept in the realm of combustion, but it lacks some qualities that, if addressed, could improve physio-chemical properties and promote energy sustainability. Recently, introducing nanoparticles (NPs) as an additive in fuel for combustion engines has become an effective practice particularly in the automobile industry, to optimize combustion efficiency and minimize emissions. Previous researchers discovered that adding NPs into biodiesel fuel improved overall engine operation performance. Thus, the objective of the research is to summarize existing research findings on nanoparticles effects on fuel properties and engine performance. The paper investigates biofuels, bio-fuel generation classifications, nano-fuel stability, performance, and limitations, as well as current research on the influence of NPs on combustion fuel properties and engine efficiency. Prior to this, researchers have discovered that employing NPs with appropriate additives and concentrations with optimal solubility significantly reduced emissions. In comparison to basic biofuel, adding CeO2 NPs to biofuel boosted brake thermal efficiency (BTE) for low and high operation by 4.1 and 12.02%, respectively. Carbon II Oxide and unburnt hydrocarbon emissions were reduced by 16.13 and 17.59%, respectively, in comparison to pure biofuel under C20-D80 + CeO2 20 ppm. However, due to the biofuel's oxygen concentration, CO2 and NOx emission reductions were not as significant. The findings indicate that utilizing a single bio-fuel generates minimal effective power, yet by incorporating nanoparticles optimizes the operation. Furthermore, future direction of the related work will be discussed particularly on the potential benefits of incorporating NPs in fuel.

Performance of a compression ignition engine fuelled with diesel-palm biodiesel-gasoline mixtures: CFD and multi parameter optimisation studies

In this research, 3D CFD simulations are conducted for a compression ignition engine fuelled with D100 (diesel), D80|BD20 (80%diesel|20%biodiesel), D75|BD20|G5 (75%diesel|20%biodiesel|5%gasoline), D70|BD20|G10 and D65|BD20|G15 mixtures. The effects of blending ratio, exhaust gas recirculation (EGR) and start of injection (SOI) on the combustion, emissions, engine output and fuel efficiency are analysed. In brief, D65|BD20|G15 produced the least nitrogen oxides (NOx) and soot emissions of 6.5E-2 and 5.46E-3 g/kWh, respectively, which were lower than the Euro VI limit. The least carbon monoxide (CO) and unburnt hydrocarbons (UHCs) emissions were achieved for D75|BD20|G5 for 1.62 and 5.8 g/kWh, respectively. D75|BD20|G15 improved the indicated mean effective pressure (IMEP), combustion efficiency and indicated specific fuel consumption (ISFC) up to 13.9%, 12.7% and 13.9% compared to D80|BD20, respectively. Also, applying 20% EGR led to 50% reduction in NOx and soot for D65|BD20|G15, while UHCs and CO were increased up to 27% and 54%, respectively and ISFC and combustion efficiency slightly declined. Additionally, advancing SOI timing to −24 Crank Angle (°CA) decreased the CO and UHCs emissions of D65|BD20|G15 up to 20% and 15% compared to −20°CA, respectively. A multi-parameter optimisation is also performed to ascertain the best operating condition, under which the emissions are mostly supressed and engine performance and fuel efficiency are enhanced.

Impact of binary blends of biodiesels on fuel quality, engine performance and emission characteristics

AbstractThe incessant pressure of energy requirements by the growing global populace has led to the exploration of unconventional methods to produce renewable and sustainable fuels. Among these, biodiesel is most suited to the present needs of eco-friendly standards to keep the atmosphere free from residual emissions. Various fuel-modification methods were developed over a couple of decades to make biodiesel suitable for diesel engines. In the present research, Jatropha curcas biodiesel and waste-cooking-oil (WCO) biodiesel were used to craft a unique binary blend to obtain desirable fuel properties and operational suitability for the diesel engine. The blend with 80% WCO biodiesel and 20% J. curcas biodiesel, which had the most suitable fuel properties, was tested on a four-stroke single-cylinder vertical diesel engine. The emissions and operational parameters were analysed and compared with diesel. The results of the study indicated that engine emissions for binary blend, carbon monoxide and unburnt hydrocarbon emissions were highly reduced, and carbon dioxide and nitrogen oxide (NOx) emissions increased relative to diesel. At full load, NOx emission was found to be 51.32% higher than that from diesel and 3.8% lower than that from WCO biodiesel. Engine performance showed that for the binary blend, at full load, the brake-specific fuel consumption was 396.82 g/kWh, which was 15.26% higher, and the brake thermal efficiency was 22.7%, which was 2.74% lower than regular diesel fuel. The present study suggests that the binary blend of J. curcas biodiesel and WCO biodiesel can be a promising approach towards advancements in the fuel properties of biodiesels.

Investigations on reduction of pollutants in spark ignition engine

With a great vulnerability to oil embargoes and shortage of fossil fuels, attention is focussed on development of alternative fuel sources. Therefore alternative fuels like alcohol are preferred due to their comparable properties with gasoline. Reduction of exhaust emissions from engines has been focused and given importance in the development of new engines. The aim of the investigations is to determine and control of pollutants of the variable speed engine with piston surface, coated with copper and also inner side of the cylinder head as well as liner fuelled with gasohol [80% of gasoline blended with 20% of ethanol] by varying timing of spark ignition coupled with catalytic converter using catalyst of sponge iron incorporating air injection in catalytic chamber. The operating conditions of the investigations were configuration of the engine and ignition timing, with and without the provision of catalytic chamber. The exhaust emissions of carbon mono oxide (CO), un-burnt hydro carbons (UBHC) and nitrogen oxide (NOx) levels were determined at various values of brake mean effective pressure (BMEP) of the engine. CO emissions, UBHC emissions and NOx levels were evaluated with sophisticated analyzer at various values of BMEP of the engine. Copper coated engine with gasohol at its optimum ignition timing reduced pollution levels. Catalytic converter reduced pollution levels by 40% and further reduction of emissions were pronounced with the injection of air. The ignition timing which was found to be optimum with CE was 280bTDC (before top dead centre), while it was 270b TDC with copper coated engine (CCE).

Effect of Kariba Weed Biodiesel Blended with n-Pentane on the Chosen Parameters of a Ceramic-Coated Thermal Barrier Direct Injection Diesel Engine.

In this experimental investigation, Kariba weed biodiesel (KSB) blended with n-pentane has been tested in conventional and ceramic-coated thermal barrier engines, and the results have been compiled and presented. A single-cylinder, four-stroke, direct injection diesel engine has been used as the test engine with eddy current dynamometer loading as used in the experimental setup. The tests were repeated in various ambient conditions to get an optimal value. Ceramic coating has been done with partially stabilized zirconia by the plasma arc spraying process. Among the quantum of tests conducted, 90% KSB blended with 10% n-pentane showed appreciable results when it was compared with the test fuel (neat diesel). The brake thermal efficiency and brake-specific fuel consumption were found to be better when compared with neat diesel. At increasing load, unburnt hydrocarbon, carbon monoxide, and smoke opacity emissions were appreciably reduced.