Search

• Feasible direct injection strategies of liquid ammonia are applied. • The maximum ammonia energy ratio (AER) reaches 86 %. • Indicated thermal efficiency for 86 % AER increases to 35 % at low load. • 70 % reduction of ammonia emissions is achieved at low load. Ammonia (NH 3), as a potential zero-carbon fuel, has garnered significant attention for its application in compression ignition (CI) engines. Due to the low reactivity, ammonia is primarily used as dual fuel in CI engines. Therefore, the decarbonization potential is influenced by the ammonia energy ratio (AER). In this study, experimental research was conducted on expanding the AER at low load conditions in a direct-injection ammonia-diesel dual-fuel engine. The ammonia post-injection strategy was explored and significantly improved the suppression effect of high-concentration ammonia on diesel ignition, which could advance ignition timing and increase the peak heat release rate. As a result, coupled with intake heating, it expanded AER to 86 % at an indicated mean effective pressure (IMEP) of 4 bar. This strategy also increased the indicated thermal efficiency (ITE) by 8 % and significantly reduced unburned ammonia emissions. However, the combustion and emission performance was limited by the post-injection ammonia quantity and the injection timing of both diesel and ammonia, especially under high AER conditions. [ABSTRACT FROM AUTHOR]

• Injection pressure varied from 180 bar to 240 bar. • Two types of nanoparticles, Ce 2 O 3 and TiO 2 , were dispersed in 20 % biodiesel blends at a concentration of 50 ppm. • Increasing engine load and injection pressure improved BTE levels, with Ce 2 O 3 blend reporting the highest BTE. • Ce 2 O 3 nanoparticles were found to be more effective than TiO 2 in reducing emissions. The current study investigated the effect of varying injection pressure on a diesel engine fueled with waste animal fats oil. The injection pressure varied from 180 bar to 240 bar, and parameters such as engine performance, combustion, and emission characteristics were determined. In addition to the biodiesel blends, two types of nanoparticles, Ce 2 O 3 and TiO 2 , were studied. A series of tests were conducted on a single-cylinder diesel engine. Both nanoparticles were dispersed in the biodiesel blends at a concentration of 50 ppm. The results indicated that increasing the engine load and injection pressure improved the brake thermal efficiency levels. The use of Ce 2 O 3 along with the blend reported the highest BTE due to its oxygen content during combustion. Higher injection pressure improved spray characteristics and combustion stability, resulting in better combustion efficiency. However, excessive pressure rise can lead to combustion instability and higher emissions. Ce 2 O 3 nanoparticles were found to be more effective than TiO2 in reducing the emission of hydrocarbons, nitrogen oxides, carbon monoxide, and soot. Meanwhile, increasing injection pressure can help mitigate hydrocarbon formation and reduce nitrogen oxide emissions, while Ce 2 O 3 nanoparticles promote a more efficient combustion process. The blend with 20 % biodiesel and 50 ppm of Ce 2 O 3 at 240 bar reported the lowest emissions. On the other hand, 20 % biodiesel with 50 ppm of TiO 2 at 240 bar showed the lowest smoke opacity emissions. The study concludes that Ce 2 O 3 nanoparticles and increased injection pressure hold promise in reducing emissions and improving combustion efficiency. [ABSTRACT FROM AUTHOR]

• The combustion characteristics of ammonia-diesel engines have been tested. • The emission characteristics of ammonia-diesel engines have been tested. • Ammonia-diesel engines are more suitable for operation in high-altitude environments. Against the backdrop of carbon neutrality, ammonia emerges as a potent alternative fuel for internal combustion engines. In this study, a 3.0-liter, four-cylinder engine was analyzed, and an intake manifold ammonia injection system was developed in conjunction with a laboratory-designed dual-fuel Electronic Control Unit (ECU) for ammonia and diesel. This setup enabled precise control over ammonia and diesel injection using INCA software. Considering the engine's performance at varying altitudes, performance tests on the ammonia-diesel dual-fuel engine were conducted at altitudes of 0 m, 1000 m, and 2000 m. The study assessed the impact of ammonia-diesel dual-fuel combustion at different altitudes on parameters such as in-cylinder pressure, heat release rate, in-cylinder temperature, ignition delay, CA50, and burning duration, along with its effects on emissions including NO x , NH 3 , and CO 2. The findings revealed that with an increase in the ammonia substitution rate, emissions of NO x and CO 2 significantly decreased, while unburned NH 3 , Particulate Number (PN), Total Hydrocarbons (THC), and CO emissions increased. Importantly, the NO x emissions from ammonia engines at high altitudes were comparable to those at sea level, and unburned NH 3 emissions were reduced, suggesting that ammonia engines are more suited for operation in high-altitude environments. [ABSTRACT FROM AUTHOR]

• Intake airflow modulation is proposed to manage exhaust O 2 concentrations. • Studied DPF active regeneration efficiency across varying O 2 concentrations. • Evaluated fuel consumption and CO 2 emissions in DPF's active regeneration phase. This study proposes a method to control exhaust oxygen (O 2) concentration by adjusting the intake throttle valve, achieving intake throttling, and reducing intake airflow. The impact of exhaust O 2 concentration at the inlet of the diesel oxidation catalyst (DOC) the diesel particulate filter (DPF) performance during active regeneration in diesel engines is investigated. Experiments are conducted under methanol substitution rates (MSR) of 0% and 20% to investigate how different exhaust O 2 concentrations affect the performance of the DOC and DPF during active regeneration. A comparative analysis of fuel consumption and cumulative CO 2 emissions during DPF active regeneration under different exhaust O 2 concentrations is performed. Research results indicate that decreasing exhaust O 2 concentration reduces exhaust flow, raising DOC inlet temperature. This enhancement improves catalytic conversion efficiency, accelerating the rise in DPF inlet temperature. The average conversion efficiency of DOC to unburned methanol exceeds 98.07%. After initiating DPF active regeneration, O 2 concentration sharply drops, leading to elevated CO 2 emissions. As soot combustion advances, the required O 2 diminishes, resulting in a gradual rise and eventual stabilization of O 2 emissions. Economically and environmentally, irrespective of MSR (20% or 0%), there exists an optimal exhaust O 2 concentration that minimizes effective regeneration time during DPF active regeneration, achieving minimal fuel consumption and the lowest CO 2 mass emissions. This study offers theoretical support for optimizing energy-saving and emission-reduction processes during DPF active regeneration. [ABSTRACT FROM AUTHOR]

X-type rotary engines (XREs), using the high efficiency hybrid cycle, possess advantages of simple structure, high power-to-weight ratio, and high theoretical efficiency, making XREs as potential power sources in hybrid vehicles and small unmanned aerial vehicles. Typically, ignition timing has a promising potential to improve the combustion performance of spark ignition engines. In this work, the effects of ignition timing on flame propagation, combustion characteristics, and pollutants formation were studied adopting a three-dimensional simulation method. The results showed that at different engine speeds, significantly different flow forms and flow velocities in the larger chamber recess of the XRE were formed, resulting in large differences in flame propagation velocities at leading side and trailing side of the combustion chamber. Advancing ignition timing increased the flame propagation velocity at the given engine speed. Ignition timing had a more significant effect on peak pressure at medium-high speeds compared to low engine speeds. At 3000 RPM and 5000 RPM, the peak pressure was increased significantly with advancing ignition timing, but when ignition timing was advanced to -30 °CA, the increment in the in-housing pressure was minimal. As ignition timing was retarded, the ignition delay was slowly reduced. The effect of ignition timing on ignition delay was more significant for low speeds than for medium-high speeds. However, the influence of ignition timing on combustion duration showed the opposite trend. Delayed ignition showed a slight increase in indicated thermal efficiency and indicated mean effective pressure at low speeds, while the opposite was true at medium-high speeds. Nevertheless, the effect of ignition timing and engine speed on indicated specific fuel consumption is opposite to the trend of the above laws. With the increase of ignition timing, the NOx mass fraction first increased and then decreased at low speeds, with the maximum occurred at -30 °CA, but the NOx mass fraction continued to increase at high speeds. Soot and CO productions were slightly affected by ignition timing. To sum up, this XRE, setting the ignition timing of -30 °CA, achieved better flame propagation and engine performance at the price of a smaller increment of NOx emissions. • The three-dimensional CFD model of the XRE was established and validated. • Effect of ignition timing on combustion characteristics of an XRE was analyzed numerically. • Large differences in flame propagation velocities in the cylinder of the XRE were caused due to larger chamber recess. • Ignition timing had a more significant effect on the ignition delay at low speeds compared to medium-high speeds. • Retarding ignition timing increased ITE and IMEP at low engine speeds. [ABSTRACT FROM AUTHOR]

[Display omitted] • RDF in wood pellets increases density, durability and moisture resistance compared to pellets without additives. • Pellets with 10 wt% RDF had the lowest temperatures of thermal decomposition cessation. • Co-pelletization of pine sawdust, cardboard and plastic increased ignition delay times compared to samples without additives. • CO, CO 2 and NO x emissions from the combustion of pellets with RDF decreased compared to wood pellets. • RDF in wood pellets increased the efficiency indicator by 12% compared to pellets without additives. Experimental research findings are reported on the ignition and combustion behavior, as well as mechanical properties of pellets from wood biomass (pine sawdust) and additives of refuse-derived fuel (cardboard, plastic and their mixture). The addition of RDF was found to increase the vibration durability and moisture resistance of pellets by 3.7–45.6% % compared to samples without additives. Cardboard and its mixture with plastic contributed to 2.7–5.8% greater density of pellets % compared to wood pellets. The impact resistance coefficient of pellets with waste decreased by 0.3– 2.3% compared to samples without additives. An increase in the proportion of cardboard and plastic led to longer delay times of the gas-phase and heterogeneous ignition. The ignition delay times decreased by a factor of 1.3–2.2 as a result of mixing cardboard with plastic compared to pellets with only cardboard or plastic. On the environmental side, the use of cardboard in pellets reduced the concentrations of carbon dioxide and carbon monoxide by 10–24 % and 5–46%, respectively, compared to samples without additives. By contrast, the addition of plastic waste increased CO 2 and CO by 4–15% and 5–63%, respectively. The combustion of pellets with RDF was characterized by 22–78% lower concentrations of NO x. The results of a multi-criteria decision analysis revealed that the use of RDF in wood pellets increased the efficiency indicator by 1 to 12% compared to wood pellets. [ABSTRACT FROM AUTHOR]

• Higher ammonia concentrations lead to a notable increase in in-cylinder pressure, enhancing combustion efficiency. • Use of ammonia enhances the engine smoothness across various load conditions. • Direct correlation between increased ammonia concentration and HRR is noted. • Highest BTE was observed mainly due to increased ammonia concentration. • Increase in ammonia content also leads to higher NOx emissions. This study investigates the potential of ammonia as a secondary fuel in diesel engines, amidst the rising interest in alternative fuels and the growth of electric vehicles. Unlike hydrogen, with its higher flammability and safety concerns, ammonia offers a viable, sustainable fuel source. A single-cylinder diesel engine was utilized to assess engine performance and combustion characteristics using ammonia gaseous blends. Ammonia was combined with biogas to mitigate its corrosive effects and compensate for its lower heating value. Th entire best conducted with constant ammonia flow rate of 30 LPM. Diesel was mixed with biogas in compositions of 10 LPM, 20 LPM and 30 LPM, and tested under engine loads of 25%, 50%, 75%, and 100%. The blend with the highest ammonia concentration (B30B3) exhibited the largest heat release rate, highlighting a strong correlation between ammonia content and heat release levels. This is attributed to the premixed combustion phase and the accelerated flame speed associated with ammonia. An increase in ammonia content resulted in higher brake thermal efficiency and reduced brake specific fuel consumption. All ammonia-inclusive blends showed a decrease in hydrocarbon and carbon monoxide emissions, with the lowest emissions observed in the B30B3 blend. However, the high flammability of biogas in the B30B3 blend, compared to diesel, and enhanced fuel atomization, led to increased nitrogen Oxides formation. The results clearly indicate that combination of ammonia along with the biogas enhances the combustion and reduces greenhouse gas emissions. Findings of this study provides valuable insights into the use of ammonia as a sustainable alternative in diesel engines, offering a improved balance between combustion efficiency and environmental impact. [ABSTRACT FROM AUTHOR]

• Nanoparticles in the blends contribute to enhanced thermal efficiency. • WC20 exhibits reduced carbon monoxide emissions, and the addition of ammonia and hydrogen further enhances this reduction. • Biodiesel blends show promise in reducing hydrocarbon and smoke emissions. • Notable change in NOx emissions due to hydrogen fraction was noted. Waste cooking oil-based biodiesel gained profound attention owing to its high calorific value and energy content. Recycling the waste cooking helps the circular economy in the perspective of sustainable energy production. Production of the energy from the waste materials can help to reduce the environmental burden. A single cylinder diesel engine used to determine the effect of the waste cooking oil on the diesel engine when they are blended with the energy fraction of hydrogen and ammonia. The flow rate of hydrogen and ammonia maintained constant throughout the entire study. The fuel scheme was 20% biodiesel tested along with 10 LPM of hydrogen and 10 LPM of ammonia. The influence of waste cooking oil blends on brake thermal efficiency (BTE), Brake specific fuel consumption (BSFC), and emissions were examined for wide range of engine loads. The incorporation of a 20% waste cooking oil blend reveals a consistent decrease in brake thermal efficiency across all engine loads due to high latent heat of evaporation. Conversely, blends with waste cooking oil, ammonia, and hydrogen exhibit increased BTE, emphasizing positive contributions to the combustion process. The introduction of TiO 2 nanoparticles yields two different outcomes based on the engine loading conditions. BSFC analysis reveals challenges in fuel efficiency with WC20, while the addition of ammonia, hydrogen, and nanoparticles reduces the overall BSFC. Emission assessments showcase reductions in CO, HC, and smoke emissions, with notable challenges in mitigating NOx emissions. Ammonia helps to reduce the carbon content in the fuel which resulted in lower CO and HC formation during combustion. [ABSTRACT FROM AUTHOR]

• Addition of RuO 2 nanoparticles increases BTE in biodiesel blends, with the highest improvement in B20R100. • Nanoparticles lowered BSFC, indicating enhanced fuel efficiency and better combustion. • An increase in oxygen concentration in biodiesel blends led to reduced emissions. • Addition of RuO 2 resulted in higher NOx emissions. In this study, the impact of RuO 2 nanoparticles and ammonia additives on the performance and emissions of biodiesel blends in diesel engines was investigated. A single-cylinder, water-cooled, internal combustion engine with a vertical stroke was utilized to evaluate the blends over a wide range of engine loads. The addition of nanoparticles had a distinct positive effect on brake thermal efficiency, with B20R100 biodiesel exhibiting the highest brake thermal efficiency values, closely followed by B20R50. Specifically, the incorporation of nanoparticles in B20R50 and B20R100 resulted in remarkable increases in brake thermal efficiency, with improvements of 12.5 % and 18.75 %, respectively. This enhancement was coupled with reduced brake specific fuel consumption, demonstrating improved fuel efficiency. The nanoparticles acted as catalysts in the combustion process, increasing cylinder pressure and decreasing ignition delay. Furthermore, the introduction of ammonia fuel in B20R50 and B20R100 blends led to additional reductions in BSFC, primarily due to more efficient and complete fuel combustion. The incorporation of RuO 2 nanoparticles and ammonia into biodiesel blends has demonstrated significant impacts on exhaust emissions. These additives have proven effective in reducing carbon monoxide and hydrocarbon emissions, contributing to reach carbon free fuel. The nanoparticles improved fuel atomization, resulting in lower CO and HC emissions, while the ammonia provided additional oxygen molecules that helped mitigate HC emissions. Smoke emissions were also reduced as the oxygen concentration in biodiesel blends increased since RuO 2 nanoparticles played a role in this reduction by modifying fuel properties. However, it's worth noting that the addition of RuO 2 nanoparticles led to increased nitrogen oxide emissions. This rise in NOx emissions was primarily attributed to the higher engine cylinder temperature induced by the nanoparticles by modifying the thermal conductivity of the fuel blend. [ABSTRACT FROM AUTHOR]

• Addition of 50 ppm and 100 ppm nanoparticles improved brake thermal efficiency, notably recording a 10.1 % increase at maximum load. • EGT increase upon nanoparticles inclusion, indicating a connection between nanoparticle concentration and combustion temperature. • Biodiesel blends exhibited a significant drop in CO emissions. • NOx levels showed no reduction across all engine loads. Ammonia is one of the promising alternatives towards the carbon free economy and highly known for its potential NOx reduction and efficiency improvement. This study investigated various performance and emissions characteristics of engines using different fuel blends such as C20, C20N50, C20N100, C20N50A, C20N100A. The blends are mixed with nanoparticles at the two different fashions of 50 ppm and 100 ppm. Added to above, the ammonia gas effects on the blends were also analyzed. In the entire study the flow rate of the ammonia maintained constant at the rate of 10 LPM. Test were conducted in the all blends across the wide range of engine loads varying at the intervals of 25 %. Inclusion of the nanoparticles enhances the brake thermal efficiency (BTE) by stimulating the combustion process. Increasing the nanoparticle concentration led to higher brake specific fuel consumption. C20 reported the highest BSFC value at 0.39 kg/kWh. C20N100 had the highest BTE values due to an increase in nanoparticle concentration, resulting in enhanced thermal efficiency. The addition of 50 ppm and 100 ppm nanoparticles to C20 biodiesel led to increase in BTE across varies engine load. Inclusion of the nanoparticles increased the exhaust gas temperature due to the enhanced combustion process. Regarding the emission, there is a massive reduction in the carbon monoxide, hydrocarbon emission, smoke opacity and nitrogen of oxides. Biodiesel increased the emission of NOx at wide range of engine loads. However, there is a slight reduction upon use of the nanoparticles. [ABSTRACT FROM AUTHOR]

• The temperature distribution of SCR carrier was tested by 9 sensors. • The effects of different post injection strategies on NO x emission and NO x conversion efficiency were studied. • The SCR temperature management strategy under WHTC transient conditions was proposed. Selective catalytic reduction technology is the main technology to reduce NO x emissions from diesel engines. In order to meet the increasingly stringent requirements of pollutant emission regulations and further reduce the low-temperature NO x emissions in the transient conditions of diesel engines, it is necessary to perform exhaust thermal management on diesel engines. Taking a diesel engine equipped with DOC + DPF + SCR + ASC aftertreatment system as the research object, the internal temperature of the SCR carrier was tested by arranging nine thermocouple temperature sensors inside the SCR carrier. The effects of different post-injection strategies (without post-injection, post-injection2, post-injection1, and post-injection2 + post-injection1) on the SCR temperature characteristics and NO x emissions were studied under WHTC condition. The results show that the center temperature was high and the edge temperature was low inside the SCR carrier. In terms of SCR average temperature, the post-injection strategies from highest to lowest were post-injection2 + post-injection1, post-injection1, post-injection2, and without post-injection. For the comparison of NO x conversion efficiency, results show that post-injection1 > post-injection2 > post-injection2 + post-injection1. Under WHTC conditions, the use of post-injection2 + post-injection1 for the first 700 s and post-injection1 for the last 700 s was the best choice for reducing NO x emissions. [ABSTRACT FROM AUTHOR]

• Brake power of biodiesel blended fuels was lower compared to diesel fuel due to their higher density, viscosity, and lower heating value. • 10% blend exhibited the highest brake power and 30% blend showed highest thermal efficiency. • Reduced carbon monoxide and hydrocarbon emissions compared to diesel fuel. • Higher levels of nitrogen oxide emissions were observed for Scenedesmus obliquus microalgae-based blends. The fossil fuel deficiency and the negative impacts of petroleum fuel use on the environment are better can be tackled and reduced with the use of biodiesel. Biodiesel is derived from mainly the debris of plants and animals gained profound attention in recent days to meet the circular economy. This research paper explores the potential of biodiesel from Scenedesmus obliquus microalgae and its performance and emission characteristics in a four-stroke, single-cylinder, naturally aspirated, water-cooled diesel engine were examined. Testing fuel quality is much more important in terms of its main functional parameters such as brake power, brake specific fuel consumption, brake thermal efficiency, and emission of carbon monoxide, carbon dioxide, hydrocarbon, and nitrogen oxides. The emission of the above said harmful gases is the result of incomplete combustion that can be resolved with the use of non-carbon nature biodiesel. The Scenedesmus obliquus biodiesel was extracted and produced by using the transesterification method. The produced Scenedesmus obliquus biodiesel blends were tested in a conventional single cylinder diesel engine. The experimental tests were conducted at 1000–3000 rpm with 500 rpm intervals at full load conditions. The SOB30% increased the brake power and torque and it was nearly equal to the results produced by pure diesel. The utilization of biodiesel leads to a reduction in brake power due to its lower calorific value and suboptimal cetane number. The viscosity of microalgae blends is higher, resulting in elevated levels of brake-specific fuel consumption. Among the different blends, the highest brake thermal efficiency is reported for the 30 % biodiesel blend. Additionally, there is a significant decrease in carbon monoxide emissions attributed to the thorough combustion process. From the results, it is evident that Scenedesmus obliquus biodiesel satisfied the requirements to be an effective alternative to petroleum fuels. [ABSTRACT FROM AUTHOR]

[Display omitted] • On Board hydrogen reformation and other production methods are discussed. • Smaller quenching distance and low density are the problems with hydrogen properties. • Ammonia and hydrogen fuels are comparitively assesed. • Direct injection, port and carburetor methods are highlighted. • A direct injection may avoid power loss but result in a higher particle formation. • Hydrogen performance and combustion in CI and SI engines are evaluated. • Ignition delay on hydrogen combustion is discussed. Hydrogen-enriched fuel has emerged as an important energy source for internal-combustion engines due to its cleanliness, continuous regeneration and efficient combustion. This review provides a synopsis of current developments in the field of hydrogen-enriched fueling for internal combustion engines. The purpose of this review article is to collect information on hydrogen enhancement in internal combustion engines and to provide a systematic viewpoint on their emissions and performance in various SI and CI engines. Firstly, the fundamentals of hydrogen enrichment followed by a full explanation of hydrogen production technologies as well as the characteristics of Hydrogen enriched mixtures of well-established IC engine fuels. In addition to this, the types of hydrogen injection systems are explained and the merits and demerits of each injection system are compared. Performance, emission and combustion characteristics of IC engines enriched with hydrogen are analyzed. Future research on hydrogen-enriched internal combustion engines has also been briefly outlined. [ABSTRACT FROM AUTHOR]

• The study examines the potential of ammonia as fuel for diesel engines in dual fuel mode, and compares it to biodiesel and nanoparticle blend. • Use of ammonia as fuel is acceptable due to its higher brake thermal efficiency and lower carbon emissions. • Consumption of fuel increased due to lower energy density and higher viscosity of biodiesel blends. • Optimizing combustion delay and avoiding premixed combustion, ammonia can be a potential substitute for diesel engine. Ammonia has emerged as a promising gaseous fuel for replacing conventional fossil fuels and achieving carbon neutrality. This research explores the viability of using ammonia as a fuel in compression ignition diesel engines operating in dual-fuel mode. The study investigates the performance and emission characteristics of diesel engines fueled with ammonia, microalgae-based biodiesel, and their combinations, with the addition of Fe 2 O 3 nanoparticles to enhance combustion efficiency. A series of experiments were conducted using various blends of ammonia, biodiesel, and nanoparticles in a single-cylinder engine. The objective was to assess the impact of ammonia and biodiesel on thermal efficiency and carbon-based emissions. Comparative analysis revealed that ammonia-based fuels exhibited higher brake thermal efficiency and lower carbon emissions compared to traditional diesel fuel. The combination of ammonia, biodiesel, and nanoparticles resulted in an 8.5% increase in thermal efficiency compared to diesel fuel. However, the fuel consumption increased by 18% due to the lower energy density and higher viscosity of the biodiesel blends. Furthermore, the study examined the emissions profile of the tested fuels. The use of ammonia and nanoparticles led to significant reductions in carbon monoxide, hydrocarbon, and smoke emissions. However, there was a slight increase in nitrogen oxides and carbon dioxide emissions, regardless of engine loading conditions. It was observed that the emission of NOx was influenced by combustion delay and autoignition temperature. To mitigate NOx emissions, optimizing the combustion delay and avoiding premixed combustion phases are crucial. Based on the findings, the study concludes that ammonia has the potential to serve as a viable substitute for diesel fuel in engines. Ammonia-based fuels exhibit higher brake thermal efficiency and lower carbon emissions. Future research should focus on optimizing combustion parameters to minimize NOx emissions, thereby facilitating the widespread adoption of ammonia in diesel engines and contributing to the decarbonization of the transportation sector. [ABSTRACT FROM AUTHOR]

• Coordinated effects of CNG injection strategy and ignition timing were studied. • CNG/gasoline combustion yielded shorter CA0-10 and less CoV IMEP , but longer CA10-90. • Both nucleation and accumulation mode particles were inhibited by dual fuel combustion. • The slow LFS of CNG can be compensated by mid CNG injection strategy. • The engine BMEP was recovered using optimal injection strategy and ignition timing. CNG was a low-carbon alternative fuel for engines, which also had the advantages of higher engine knock resistance and better fuel/air mixing. The CNG injection and ignition timing was of significant importance for the performance of Dual Fuel Spark Ignition (DFSI) engines. In this paper, the coordinated effects of CNG injection strategy and ignition timing on the combustion and emission characteristics of CNG/gasoline DFSI engines were investigated. The results showed that the CNG/gasoline engine can achieve a comparable level of BMEP to that of a pure gasoline engine by using the CNGDI plus GPI injection approach with an optimal combination of injection and igniting timing. The cyclic variations of CNG/gasoline engines were increased with the advancing of ignition timing, and these variations can be ceased by using proper CNG injection strategies (early or mild). The gaseous emissions (HC, CO, and NOx) of CNG/gasoline engines were equivalent to those of pure gasoline engines; but the PN emissions were lower than that of gasoline engines. The particle size distribution of CNG/gasoline DFSI engines followed a single peak nucleation pattern and most of the particles were in nucleation mode (d ≤ 50 nm) peaking at around 15 nm. This study would be beneficial for the application of CNG in gasoline engines, which was promising to alleviate the strong dependence of engines on petroleum energy and to reduce their greenhouse gas emission. [ABSTRACT FROM AUTHOR]

• Maximum BTE of 44.9% was achieved in a small bore spark-ignition passenger car engine. • Methanol direct injection extends lean burn flammability by only about 0.1. • Methanol direct injection and high CR increase CO and HC emissions at high dilution rate. • The main barrier to greater BTE for spark ignition MDI engine with high CR are extended combustion duration and increased incomplete combustion. The high octane number and high latent heat of vaporization of methanol are beneficial to suppress knock and consequently increase compression ratio (CR) of spark ignition engines, and thus improve the thermal efficiency. Few preious research on methanol engine combuston and performances have been conducted based on spark-ignition passenger car engines with a CR greater than 14. In this study, a 1.5-liter spark ignition passenger car engine with miller cycle was used to explore the potentials of high CR and methanol direct injection (MDI) on improving engine performances. First, the engine was tested under stoichiometric combustion using methanol and gasoline at BMEPs of 1.1 MPa and 1.5 MPa with CR11.5, CR13.8, and CR15.3. Then, the performances of the CR11.5 case with gasoline and the CR15.3 case with methanol were compared under lean burn combustion. The results show that for gasoline, increasing CR from 11.5 to 15.3 results in decreased fuel economy under stoichiometric combustion, whereas the exact opposite tendency is shown for methanol. Integrating a high CR of 15.3 and MDI improves brake thermal efficiency (BTE) to 43.3 % at an excess air/fuel ratio (λ) of 1.0, when compared with 37.4 % of gasoline at CR11.5. Applying lean burn can further improve the BTE of methanol at CR15.3 to 44.9 %. The main causes of the improvement of BTE by high CR and MDI are the reduced exhaust heat loss resulted from earlier combustion phasing. However, high CR and MDI also extend combustion durations at all specified λs, and emit more THC and CO emissions than low CR with gasoline at high λs because of higher surface/volume ratio and flame quenching. The extended combustion duration and the incomplete combustion are the main barriers to greater BTE for MDI sprak ignition engine with high CR. [ABSTRACT FROM AUTHOR]

• A Wankel engine simulation model at various altitudes was established and validated. • Combustion duration in the working chamber of the Wankel engine is extended at higher altitudes. • The Wankel engine performance decreases, and the emissions deteriorate when the altitude increases. This study investigates the effects of altitude on the combustion, emissions, and performance of a Wankel engine for unmanned aerial vehicles (UAVs). The main motivation behind the presented study is to contribute to the Wankel engine designs used as a power source in UAVs by revealing the operating conditions at various altitudes. For these purposes, a gasoline fueled Wankel engine was simulated at sea level conditions for different equivalence ratios and results were validated with their experimental counterparts. Then, CFD simulations were carried out at various altitudes (6000 ft, 10,000 ft, and 15,000 ft). The simulation results show that decreasing ambient air temperature, and pressure at higher altitudes reduces the fresh charge density, hence combustion efficiency and heat release rate (HRR). As a result, the performance characteristics such as the indicated mean effective pressure (IMEP), the indicated torque, and indicated power decrease and exhaust emissions increase. For 6000 rpm, IMEP decreases by 39.11%, 53.79%, and 69.22%, and the indicated power reduces by 35.51%, 52.47%, and 65.05% at the altitudes of 6000 ft, 10,000 ft, and 15,000 ft, respectively, compared to those obtained at the sea level conditions. As for exhaust emissions, CO and CO 2 are lowest at sea level conditions and increase with altitude. [ABSTRACT FROM AUTHOR]

• Chlorella Vulgaris microalgae were used as the test fuels, with the biodiesel mixed with pure fossil fuel in volumetric ratios ranging from 10% to 30%. • Transesterification was used to prepare the biodiesel. • The findings suggest that microalgae biodiesel is a more economical and effective replacement for fossil fuels in powering micro gas turbine engines. • NOx emission was slightly higher compared to plain biofuel, indicating a need for further research to optimize performance and reduce emissions. The significant benefits of microalgae biofuel have made it a preferred choice in various industries, including aviation. Microgas turbine engines can be promising choice for highway vehicles. This research paper investigates the process of producing fuel from microalgae, as well as its performance and emission characteristics in the micro gas turbine engine operating at sea level conditions for highway vehicle applications. A two-step extraction and transesterification process were employed to convert the biofuel, using a batch stirrer reactor for esterification. The preparation of biofuel blends followed the volume fraction method at the concentration of 10% and 30%. Additionally, nanoparticles were incorporated into the blends at a 50 ppm concentration to enhance overall characteristics of the engine. Titanium dioxide nanoparticles, known for their high surface-to-volume ratio, were used for this purpose. Experimental tests were conducted on a 30 kW micro gas turbine engine to evaluate the fuel's quality in terms of performance and emissions. Various parameters were measured at different engine speed, including 30,000 rpm, 40,000 rpm, 50,000 rpm, 60,000 rpm, and 70,000 rpm. The results obtained clearly demonstrate that the optimal blending of biofuel with neat Jet-A fuel improves performance by generating the required thrust while significantly reducing harmful gas emissions. Furthermore, the addition of nanoparticles acted as a catalyst and enhanced the quality of the fuel blends, making them an efficient alternative for aircraft engines as well. Added to above, there is an significant reduction in the emission of the CO has been noted across wide range of speed. From the results it is evident that microgas turbine engine can be an ideal choice for the highway vehicles to meet reduced carbon emissions. [ABSTRACT FROM AUTHOR]

• DFT application on arsenic behavior in coal-fired power plants. • Mechanisms of arsenic behavior in a typical pulverized coal combustion system and related equipment. • Current gaseous arsenic capture technologies using sorbents. • An outlook on DFT application on arsenic behavior in power units. Arsenic is one of the World Health Organization's 10 chemicals of major public concern. Coal-fired power is the major anthropogenic source for arsenic emission, and will remains a major contributor to energy production worldwide in the foreseeable future. In combination with experiments, quantum chemistry offers a profound overview of arsenic behavior and possess a predicted effect for arsenic emission. This work summarizes the application of density functional theory (DFT) on arsenic behavior in coal-fired power plants, and is divided into two parts: (1) Mechanisms of arsenic behavior in a typical pulverized coal combustion system and related equipment, with the aim of enhancing cooperative control of arsenic emission from existing equipment in power units. Given that trapping gaseous arsenic species on large particles using sorbent is an effective method to suppress the arsenic emission, part (2) introduces the current gaseous arsenic capture technologies using sorbents, and summarizes information on arsenic adsorption for typical sorbents including Ca, Fe and Al-based materials. Finally, the paper provides an outlook on DFT application on arsenic behavior in power units to guide the development of new cost-effective approaches for reducing the arsenic emission. [ABSTRACT FROM AUTHOR]

• 3E analysis of Mesua Ferrea seed oil biodiesel run diesel engine. • Retarded IT improves BTE of Mesua Ferrea seed oil biodiesel run diesel engine. • Retarded IT reduces exergy destruction for Mesua Ferrea seed oil biodiesel run diesel engine. • CO and HC emissions reduce on retarding the injection timing. Biofuels can be used in diesel engine for power generation to address the twin problems: fossil fuel depletion and the rise of pollution. In this regard, the present work explores the possibility of enhancement of performance of Mesua Ferrea seed oil biodiesel run diesel Engine through operation at different injection timings and load settings. The investigation is carried out through energy, exergy, and emission (3E) analysis. For experimentation, a research test engine of 3.5 kW is considered. Four injection timings (20° bTDC, 23° bTDC, 25° bTDC, 28° bTDC) and five load settings (20%, 40%, 60%, 80%, 100%) were taken for the test. The results indicate that the retarded injection timing of 20° bTDC results in an improvement of fuel conversion efficiency, as well as a lowering of both exergy destruction and emissions for Mesua Ferrea seed oil biodiesel, run a diesel engine. At injection timing of 20° bTDC for 100% load, the maximum brake thermal efficiencies and maximum exergetic efficiency were found to be 26.11% and 30.32%, respectively under biodiesel mode as compared to 27.76% and 30.74%, respectively for diesel mode. For the same injection timing, the average drop in CO, CO 2, and HC emissions were found to be 46.22%, 1.62%, and 39.67%, respectively whereas the average increase of NO X emission was found to be 8.08% in comparison to diesel mode. [ABSTRACT FROM AUTHOR]

The combustion processes of biomass occurring in furnaces run with an emission of exhaust gas consisting of groups of chemicals which occur both in gaseous and particulate-bound form. The purpose of the work presented in this paper was to investigate the impact of wood combustion processes occurring in domestic heating units (DHUs) on the emission of particulate matter (PM) and other exhaust components. The process of combustion was divided into three steps: A. firing, B. combustion, and C. post-combustion. During fuel burning, the weighting platform was used to measure variations in the mass of fuel and a gaseous analyzer was used to measure gaseous exhaust components such as CO 2 , CO, O 2 and SO 2. A dust sampler equipped with a dilution tunnel, a filter holder and a pump were installed in the stack. The samples of PM were collected on quartz fiber filters with a diameter of 47 mm. The PM was then analyzed for the presence of inorganic and organic components. The results obtained in the studies confirmed the influence of using the accumulation layer on the emitted exhausts. Application of accumulation layer led to decrease the emission of gaseous fumes (NO, NO x and SO 2), although, the CO and PM emission were higher. One also observed the impact of combustion phase on the chemical composition of collected PM. The highest measured concentrations of analyzed PAH compounds were determined for acenaphthene (Ace) and benzo(a)pyrene (BaP). In all analyzed events BaP mostly contributed to the budget of PAHs in the final phase of burning: during the post-combustion process, when the temperature in the combustion chamber decreased. The application of the accumulation layer enabled to decrease the BaP concentration in the ignition phase of burning. The highest concentration of Ace was observed for the combustion phase using the Stove 1, while in the Stove 2, both with and without an accumulation layer, the Ace concentration was higher in the initial phase of burning. [ABSTRACT FROM AUTHOR]

• The coupled response of coal oxidation and sodium reactions is studied. • Sodium species are scrutinized in both one- and two-dimensional flames. • Na, NaOH and NaCl drive the sodium chemical paths in coal flames. • HCl has a much stronger ability to react with sodium species than SO 2. Sodium emissions during pulverized-coal combustion (PCC) are known to result in severe ash-related operating issues of coal furnaces, e.g., fouling, slagging and corrosion. To relieve these issues and advance the clean utilization technologies of coal, a better understanding of the fundamental mechanisms driving the formation and transformation of the sodium species is required. In the present study, sodium emissions have been simulated in both one-dimensional (1D) premixed/diffusion flames of the coal volatile and an early-stage two-dimensional (2D) pulverized-coal flame. The properties of Loy Yang brown coal are used. The DRM22 skeletal mechanism is employed for volatile-gas combustion, and the reaction of sodium species is modeled by a detailed mechanism encompassing the elements Na, C, H, O, S and Cl. The compositions of the volatile fuels are obtained from the chemical percolation devolatilization (CPD) model, including CH 4 , C 2 H 2 , CO, H 2 , CO 2 and H 2 O. The initial species of Na, Cl and S in the volatile gas is set to be NaOH, HCl and SO 2 , respectively. The transformation characteristics of 12 sodium species are investigated in both the 1D volatile flames and the 2D pulverized-coal flame. The response of the sodium chemistry to volatile-gas combustion is analyzed under fuel-lean, stoichiometric and fuel-rich conditions. Na, NaOH and NaCl are found to be the major sodium species during the combustion. Parametric studies with HCl, SO 2 or both species removed from the volatile are then performed to investigate their effects on the sodium transformation characteristics in both the 1D and 2D flames. The results show that HCl has a much stronger ability to react with sodium species than SO 2. [ABSTRACT FROM AUTHOR]

Highlights • Emissions of dual fuel (diesel – natural gas) technology are effectively predicted by the data-driven model. • Uncertainties of prediction are mostly in the range of 2.7%−10.1%. • Our model can be integrated in existing LCA tools such as OPGEE. • This is an innovative application of data-driven model to analyze dual fuel technology for the purpose of LCA. Abstract Life cycle assessment (LCA) is a powerful tool and schematic model to evaluate an emerging technology in the oil and gas industry. In the oilfield operations such as drilling and hydraulic fracturing, dual fuel (DF) diesel engines utilize natural gas and diesel fuel simultaneously, thereby reducing diesel fuel consumption and offering certain emissions reductions. Emissions from DF engines can vary greatly depending on fuel consumption and how the engine is operated. In this study, linear regression and cross validation are applied to analyze field testing data of dual fuel engines. This study enables rapidly prediction of emissions and filling of data gaps for fuel efficiency, substitution ratio and other parameters to optimize DF engine operations. Greenhouse Gas (GHG) emissions are predicted by linear regression with uncertainty of 2.7% based on power, methane loss, natural gas and diesel consumption. Exhaust after-treatment system (ATS) adds complexity and will significantly increase prediction uncertainty for carbon monoxide (CO) and non-methane hydrocarbon plus oxides of nitrogen (NMHC + NOx). This model could potentially be integrated into an engineering-based LCA tool – such as the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) to predict environmental impacts for a range of energy consumptions. This is an innovative application of multiple linear regression and cross-validation to analyze dual fuel technology for the purpose of LCA. [ABSTRACT FROM AUTHOR]

Abstract Depletion of fossil fuel resources and continuous release of greenhouse gasses to the environment forces the researchers to develop alternative fuel technologies that are environmentally more acceptable. Trans-esterified vegetable oil derivatives also called 'biodiesel' appear to be the most convenient method of utilizing bio-origin vegetable oils as replacement fuels in diesel engines. In the present study, biodiesel was prepared from non-edible rapeseed oil through the trans -esterification process and the property of biodiesel was compared with standard diesel fuel. The methyl esters of vegetable oils cope well with the existing engine hardware and do not require noticeable modification. Experiments were carried out to analyse the performance, combustion and emission characteristics of a four stroke, single cylinder 5.95 kW, direct injection diesel engine fuelled with diesel, rapeseed oil biodiesel and diesel–biodiesel blends at a constant injection pressure of 200 bar. The performance parameters such as brake thermal efficiency, brake specific energy consumption, exhaust gas temperature and combustion characteristics such as in-cylinder pressure, heat release and ignition delay of the engine were evaluated. Unburned hydrocarbon, carbon monoxide, oxides of nitrogen and smoke emission of the engine were also measured for all the test fuels. The results of the experimental investigation with biodiesel blends were compared with that of baseline diesel. The test results revealed that B25 blend can be used in the diesel without making any modification in the engine with acceptable thermal efficiency and improved exhaust emissions. [ABSTRACT FROM AUTHOR]

Abstract In this research, a comparative study of combustion characteristics, performance and emissions of a turbocharged diesel engine fueled with diesel and methanol-Fischer-Tropsch (F-T) diesel-biodiesel-diesel blends at various simulated altitudes (0 m, 3500 m and 5500 m) were conducted. The blends were composed of diesel, methanol, F-T diesel and biodiesel at volume fractions of 65%, 15.2%, 15.6% and 4.2%, respectively. Diesel was used as the baseline fuel, methanol, F-T diesel and biodiesel were used to improve the atomization characteristics, cetane number and stability of the blends, respectively. The results indicated that the cylinder pressure, pressure rise rate and heat release rate of the engine fueled with the blends were lower than those of the diesel at an altitude of 0 m, but higher at an altitude of 5500 m. Peak torque values for the test fuels both appeared at 1400 rpm near the sea level and the speeds corresponding to the peak torque values increased with altitudes. The use of the blends improved the engine power and economic performance at low-speed ranges at an altitude of 3500 m but a dramatically reduce was observed at 5500 m. Compared with the diesel, the particulate matter (2.5 (PM 2.5)) for the blends was markedly lower, while a slightly higher in NOx at various altitudes. [ABSTRACT FROM AUTHOR]

Highlights • Combustion and emission characteristics of biodiesel and biodiesel binary blends are evaluated with experiments and modeling. • Altered the composition of karanja by blending with coconut biodiesel and hydrogenation. • Maximum model prediction error is 7% and 18% for NO and soot emissions. • Hydrogenation along with similar injection timing of diesel significantly reduces the NO emission. Abstract Recent research works show that the biodiesel is one of the most promising renewable and sustainable fuels for diesel engines because it is biodegradable, oxygenated, sulphur free and renewable in nature. The major issue in using the biodiesel fuel is the increase in oxides of nitrogen emission compared to that of fossil diesel which is coined as Biodiesel-NOx penalty. Hence, it is attractive to focus on the parameters that mitigate the NOx emission for enhancing the usage of sustainable biodiesel fuels. Therefore, this paper presents comprehensive experimental investigation and multi-zone phenomenological model for analyzing the combustion and emission characteristics of biodiesel fuels. The test fuels include the baseline diesel, karanja, coconut biodiesel, binary blends of karanja, coconut and hydrogenated karanja samples. The model results are validated with the experimental results at a wide range of speed and load conditions. The model predictions are observed to be matching well with the measured data with a maximum prediction error of 7% and 18% for NO and soot emissions respectively. The parametric investigations in terms of experiments and validated model to study the effect of start of injection, fuel formulation and blends of biodiesel fuels on the emission characteristics of biodiesel fuels demonstrate that biodiesel-NOx penalty could be alleviated by restoring the start of injection of biodiesel fuel to that of diesel and through fuel formulation technique. While, the binary blends of karanja and coconut does not significantly alter the emission characteristics at lower speed, it shows a beneficial effect on NO emission at higher speeds. [ABSTRACT FROM AUTHOR]

• Karanja and safflower blends were tested in the DI engine at 20% and 40%. • Copper oxide nanoparticles of 50 ppm were incorporated in biodiesel blends. • Nanoparticles enriched fuel reported reduced BSFC than other test blends. • Combustion Noise, performance and emission characteristics of diesel engine were assessed. Studies have demonstrated that biodiesel may be used as a suitable replacement for conventional diesel fuel due to its many advantages. Negative effects, such as low energy generation, increased fuel use, and NOx emissions, must be addressed, however. As a result, biodiesel with enhanced quality, performance, and emission characteristics can be achieved by the use of environmentally friendly nano-additives. Karanja and Safflower oil mixes were used in this study to determine the engine's performance and emissions. Engine speed ranging from 1200 rpm to 2400 rpm was employed on 20% and 40% fraction ratio of biodiesel along with nanoparticles to assess emission and performance metrics. Copper oxide nanoparticles of 50 ppm were blended with different biodiesel fractions through ultrasonication. At 2100 rpm, the brake power, NOx emissions, and smoke capacity were all found to be optimal. All blends' BTE and BSFC had not shown a significant difference from diesel. When the copper oxide nanoparticle was added to the engine, it improved the engine's combustion and performance characteristics, regardless of the engine speed. Karanja outperformed safflower biodiesel blends in terms of performance and emissions. There was no discernible difference between the two blends in terms of combustion noise. The use of nanoadditives decreases the combustion noise marginally as compared with biodiesel fuel. Researchers' findings demonstrate that the antioxidant properties of karanja and safflower improve performance in biodiesel blends. [ABSTRACT FROM AUTHOR]

• Use of hydrogen as a fuel in aircraft gas turbine engines and its impact on operating parameters were reviewed. • Green routes for hydrogen production and storage towards sustainable methods were proposed. • Modifications to the engine system are necessary for implementing hydrogen as a fuel in aircraft gas turbine engines. • Modifying the engine system is necessary to accommodate hydrogen as a gaseous fuel. • Soring the hydrogen in the aircrafts were challenging due to its low density. Hydrogen is being recognized as a versatile energy carrier that can aid in the transition towards a decarbonized energy future due to its high specific energy density. Gas turbine engines are primary source of energy for the modern aircraft. To make the air transportation economical it is essential to achieve higher thermal efficiencies and the capability to operate on carbon–neutral fuels such as hydrogen. The current review article examines the effect of hydrogen in the gas turbine engines. Furthermore, the green routes for the hydrogen production and storage were discussed in detail. Additionally, the implementation of the conceptual design for the onboard hydrogen utilization in the long-range endurance aircrafts was considered. The utilization of hydrogen as a fuel in gas turbines is subject to the influence of different factors, including the functioning of the turbine components, ambient conditions, combustion stability, flame characteristics and operating parameters. This study explores the use of hydrogen as a fuel in aircraft gas turbine engines, which has the potential to reduce NOx emissions, improve fuel efficiency, and increase range while significantly decreasing pollutants such as carbon monoxide. However, modifications to the engine system are necessary, and careful consideration of factors such as fuel storage, combustion, and emissions is essential. While there are significant challenges to storing hydrogen for use as a fuel in aircraft, finding an optimized solution is crucial for reducing carbon emissions and moving towards a more sustainable future. Overall, hydrogen has the potential to be a viable alternative to conventional fuels in aircraft engines. [ABSTRACT FROM AUTHOR]

[Display omitted] • Use of Calophyllum inophyllum oil as an alternate fuel. • Induction of Hydrogen reduces BSFC. • Reduction in emission characteristics with hydrogen. • Improvement in brake thermal efficiency for P20 is around 5.34 %. Hydrogen gas is largely used as a significant supplementary fuel for CI engine due to its clean combustion, high energy content, and abundance. In this research, the engine was made to operate in dual fuel mode with Calophyllum Inophyllum Oil (CIO) diesel blend and hydrogen gas. CIO was directly injected into the combustion chamber through direct injector and hydrogen gas in the intake manifold. The engine was subjected to operate at different loads ranging from 0 to 100 % with the interval of 25 %. The CIO was blended with diesel in two proportions with 20 % and 40 %. The hydrogen gas was supplied at three different flow rates of 10, 20 & 30 L per minute. The maximum energy share of hydrogen induction was limited to 14.38%, 13.05%, and 11.28%, respectively, at full load for diesel, P20, and P40 respectively. Brake thermal efficiency for P20 and P40 at maximum energy share is increased by around 5.34% and 2.01% compared to diesel at full load conditions and also, hydrogen induction with CIO blends shows a promising reduction of pollutants such as CO by 14.89%, HC by 90.1%, and smoke by 32.65% compare with neat diesel. A prolonged ID ignition delay was also observed by the inclusion of pilot fuel and hydrogen due to pre-ignition of the fresh charge. Moreover, this investigation found that the blend of P20 with 13.05% hydrogen sharing at full load significantly improved performance, combustion, and emissions characteristics. [ABSTRACT FROM AUTHOR]

• Automative Compression Ignition Engine Powered by Cerium Oxide Nanoparticles Doped Water Diesel Emulsion Fuel. • To explore the performance of internal combustion engines by combining diesel, biodiesel, water, and nanoparticles. • Water emulsion blended fuel with nanoparticles addition in diesel engine. • Diesel engine was studied using the produced blended fuel. • The NOx discharge sizes for diesel, E 15 , E 15 CeO 240 , E 15 CeO 260 , and E 15 CeO 280 , respectively. The rising consumption of oil and air pollution in developing countries compelled us to seek suitable alternative fuels for the existing compression ignition engines used in power generation, transportation, and industrial sectors, all of which play a strong role in the development of the nation's economy. Moreover, rising demand and consumption also causes a huge impact on our economy as we are dependent on other nations to cater to our needs as domestic production fails to fulfill the present requirement and leads to huge import bills that affect the ordinary man. A water/diesel (W/D) emulsified formulation helps to diminish the engine exhaust discharge without compromising the engine's performance. The current task experimentally evaluates the execution and discharge characteristics of cerium oxide nano-particles doped water diesel emulsion fuel viz E 15 , E 15 CeO 2 (40), E 15 CeO 2 (60), and E 15 CeO 2 (80) on multi-cylinder automotive compression ignition engine at steady 1650 rpm, under variable test load situation. Mechanical stirring was used to make E 15 water diesel emulsion fuel, whereas ultrasonicator and mechanical stirrer were used to make E 15 CeO 2 (40), E 15 CeO 2 (60), and E 15 CeO 2 (80) blends. Surfactants span 80 and tween 80 were used. The concentrations of cerium oxide nanoparticles in emulsion fuel samples were 40, 60, and 80 ppm, respectively. The characteristics like thickness, flash point, and heating value of test fuels were evaluated and reported within the range as specified by governing standards. The execution and discharge characteristics of various emulsion fuel samples were compared to standard diesel. At maximum load, cerium oxide doped fuels greatly improve engine performance while lowering environmentally harmful engine pollutants such smoke opacity, NOx, carbon monoxide, and hydrocarbon emissions by 40.27%, 33.60%, 30%, and 18.75%, respectively. [ABSTRACT FROM AUTHOR]

• The VNT had the same ability to enhance the intake air flow at different altitudes. • The effect of altitude on diesel engine performance was similar to that of the VNT. • The combustion process could be improved by regulating the VNT at high altitudes. • The VNT has more influence on CO, HC, and soot emissions in plateau areas. With social and economic developments, more light-duty vehicles are operating at high altitudes, but the reduced intake air flow in plateau areas, leads to poorer engine combustion and greater emissions. An effective means of improving plateau adaptability are light-duty diesel engines employing variable nozzle turbochargers (VNTs), but the research to date on how VNTs influence the combustion and emissions of diesel engines at high altitudes has lacked both depth and a systematic approach. Therefore, in the present research, experiments were conducted to investigate the influences of a VNT on the combustion and emissions of a light-duty diesel engine at different altitudes (0 m, 1000 m, and 2000 m) by using a plateau-environment simulation device. Also, the influences of altitude and VNT nozzle opening on the in-cylinder working process and pollutant generation were studied by means of three-dimensional numerical simulations. The results show that the VNT had almost the same ability to enhance the intake air flow at different altitudes within the same range of VNT nozzle opening, and the effect of increasing altitude on diesel engine performance was similar to that of increasing VNT nozzle opening. With increasing altitude or VNT nozzle opening, the spray penetration length increased, the in-cylinder equivalence-ratio distribution became less even, the start of combustion was delayed slightly, the combustion duration was extended, and the in-cylinder mean temperature increased. With increasing altitude or VNT nozzle opening, the emission of NO x decreased gradually, while those of CO, HC, and soot increased. Compared with the case at sea level, the influence of VNT nozzle opening on CO, HC, and soot emissions was more significant in plateau areas. [ABSTRACT FROM AUTHOR]

• A dual-fuel combustion engine powered with biodiesel/diesel pilot and producer gas. • An MLP-ANN model using a 3–10-6 topology of three layers was successfully developed. • Combustion-emission characteristics were model-predicted and optimized. • A considerable reduction in exhaust emissions was discovered. • In a lab-based test, the model's errors were determined to be less than 5% Diesel engines have been blamed for harming the environment owing to toxic emissions that raise glasshouse gas (GHG) levels. This study intends to model-forecast and improve the emission and combustion parameters of a dual-fuel combustion engine fueled by biodiesel/diesel pilot and producer gas (PG), which burn cleaner than fossil diesel. To assure a high part of locally producible green fuel, biodiesel was made from waste cooking oil, and PG was made from Babool waste wood. Experiment data were obtained at varied engine loads, fuel injection timings, and pilot fuel mix ratios. Using the experimental data, a multi-layer perceptron architecture was used to create an Artificial Neural Network (ANN) based prediction framework to predict outcomes such as brake thermal efficiency, brake-specific energy consumption, oxides of nitrogen, carbon monoxide, unburnt hydrocarbons, and peak in-cylinder pressure. Statistical measures for the predictive model viz., R (0.964 – 0.998) and R2 (0.9292 – 0.996), and root mean square error (0.008 – 2.185) prove the model's robustness. Using the desirability technique, the trade-off analysis between efficiency and emission showed that 74.37% engine load, injection timing of 27 degrees crank angle before top dead center (°CA bTDC), and a 20% biodiesel/diesel blend were the ideal operating conditions. An experimental investigation confirmed the prediction errors were fewer than 5%. Using this reliable hybrid approach of predicting and optimizing the performance of a dual-fuel engine, a considerable reduction in exhaust emissions with an acceptable level of engine performance was discovered, which would reduce the negative impact on the environment. [ABSTRACT FROM AUTHOR]

Biodiesel with small modification in its constituent has been often subjected to experimental analyses in diesel engine in order to substitute it as fuel for diesel engine. Environmental friendly aspects like biodegradability, renewability, easy and safety handling characteristics of biodiesel has been desired by all. But, the biodiesel has the negative side apart from its meritorious side. The performance and emission parameters of biodiesel like BSFC, BTE, smoke emission and NO x emission has not meet out the emission norms prescribed by statutory bodies. Nano additives are found to be helpful in improving the fuel quality of improved performance and emission characteristics. In this study copper oxide (CuO) nano particles are mixed with pongamia biodiesel and subjected performance and emission analysis of engine operating characteristics in diesel engine. The experimental results provides a constructive result of 4.01% increase in BTE, a reduction of around 1.0% in BSFC and a reduction of around 12.8% in smoke emission and 9.8% reduction in NO x emission for the blend B20CuO100. [ABSTRACT FROM AUTHOR]

Both concentration stratification and reactivity stratification are beneficial for reducing the combustion rate and controlling the combustion phasing in HCCI (homogeneous charge compression ignition) operation. However, the different effects on combustion and emissions of concentration and reactivity stratification have not been fully explored and the interaction between the two stratification modes also needs to be clarified. Therefore, the effects of concentration stratification and reactivity stratification on combustion and emission characteristics were investigated in a single-cylinder diesel engine. The different concentration stratifications were designed by five port injection ratios to study the influence of concentration stratification. Cases with and without reactivity stratification were compared at the same overall reactivity and the same concentration stratification in the cylinder to roughly separate the impact of reactivity stratification. Results show that with the decrease of the premixed ratio, the peak heat release rate decreases, combustion phasing delays, and the thermal efficiency show the tendency of first decreasing and then increasing. For cases with same concentration stratification, the introduction of iso-octane/n-heptane reactivity stratification decreases combustion efficiency but increases indicated thermal efficiency, NOx (nitrogen oxides) emissions can be improved while CO (carbon monoxide) and HC (hydrocarbon) emissions are increased. The introduction of n-heptane/iso-octane reactivity stratification presents a positive effect on both thermal efficiency and combustion efficiency and contributes to the improvement in NOx, CO and HC emissions. [ABSTRACT FROM AUTHOR]

The inevitable rise in the usage of plastic poses a serious threat to the environment owing to their non-biodegradable nature. The lack of proper infrastructure for treating and recycling plastic wastes give rise to the disposal problem. However, the oil synthesized from these waste plastics can be used as an alternative fuel for C.I engines which not only helps to tackle the disposal problem but also aids in recovering precious energy from these wastes. This experimental investigation aims to study the effects of plastic-diesel blend(P30) fuel on the performance, emission and combustion characteristics of a twin cylinder CRDI engine operating at different EGR rates (0%, 10% & 20%). The experimental results showed a slight drop in the engine performance while operating with plastic blend, mainly overall due to its higher viscosity and lower heating value. The vast upsurge of NO X emissions with plastic blend was mitigated by the aid of EGR methodology. Marginal increase in the discharge of regulated emissions like HC, CO and soot were noticed for both plastic blend as well as EGR operations. The experiments were carried out for five different loading conditions varying from 0% to 80% in steps of 20% each and found out that waste plastic-diesel blend can be successfully used as an alternative fuel in diesel vehicles without any prior modifications in the engine. [ABSTRACT FROM AUTHOR]

An experimental investigation has been conducted to explore the effects of direct-injection (DI) fuel properties in dual-fuel reactivity-controlled compression ignition (RCCI) combustion on a single-cylinder, heavy-duty diesel engine. The combustion and emission characteristics of four DI fuels with cetane number (CN) ranging from 34 to 100 were compared under different combustion boundary conditions. The results showed that a higher CN DI fuel allows more advanced SOI timing, more EGR, and higher premixed ratio. However, although the operable DISOI timing and EGR regions can be extended, the operable Rp region is narrowed for higher CN fuels. In addition, there is a competing relationship between DI fuel CN and EGR/premixed ratio (Rp) in controlling CA50, PPRR, and HC/CO emissions. With late injection strategy, enlarging the reactivity gradient through increasing CN of DI fuel shows more promising effects on combustion rate and pressure rise rate reduction, which is desirable for high load extension. Comparing the highest indicated thermal efficiency (ITE) cases of different CN fuels, it’s illustrated that the approach of lower EGR (<45%) with high Rp (∼80%) is suitable for low CN fuel (i.e. CN34) with early injection strategy to obtain a lower PPRR and a better ITE simultaneously. However, at late injection condition, more EGR with lower Rp (<80%) is required to control NOx/soot emissions. For high CN fuel (CN ≥ 56), the approach of higher Rp (>80%) with high EGR (∼45%) is suitable with either early or late injection strategy to simultaneously improve the PPRR, ITE and NOx/soot emissions. [ABSTRACT FROM AUTHOR]

With continuing improvements in the efficiencies of the flue gas pollution control devices, a greater proportion of mercury emitted from coal fired power plants is in the recovered byproducts, such as fly ash and desulfurization gypsum. The leaching ability and bioavailability of mercury are related with its speciation and finally determine the total emission of mercury from power plants. Therefore, it is important to understand the speciation of mercury in the byproducts. In this study, mercury in the gypsum samples from eleven power plants in Hebei Province, China was determined in five sequential extracts representing fractionation of mercury species, namely water soluble fraction (WS, F1), ion-exchangeable fraction (IE, F2), acid soluble fraction (AS, F3), elemental fraction (EF, F4) and sulfide fraction (SF, F5). The leaching ability and the distribution of mercury in the various fractions from different power plants were examined. The results showed that mercury was dominantly in elemental fraction, and the leaching ability as well as the fraction distribution of mercury varied with samples from different power plants. The rapid release and releasable mercury in gypsum which shouldn’t be overlooked were taken into account for the estimation of mercury emission from coal fired power plants. Three models, including Mass Balance model (MB), Emission modification factors model (EMF) and Flue calculation model (FC), were also employed to estimate the possible mercury emission from flue gas in these studied power plants. A comparison of the results from the different models indicated variability among the different models. The mercury re-emission from gypsum to the environment is needed to address the important issue of further improvement of these models for estimation of mercury emission. [ABSTRACT FROM AUTHOR]

The continues and tireless researches on the development of biodiesel is still going on because of the demand and the expectation of the biodiesel is not meet out to replace the environmental hazardous fossil fuel. India the country with rich flora and fauna and great geographical topology for growing all types of plants and with 80% of the population practicing agriculture for their livelihood has not satisfactorily meet out the requirements of biodiesel production. The researches were repeatedly carried out in limited biodiesel feedstock and new feedstocks are neither tried nor tried in a reluctant manner. If studies of biodiesel with all available plant oils were carried out extensively and exclusively, the rural employability and the production would have been boomed up and if found suitable for replacing diesel the demand to supply gap will be filled. In this experimental study the biodiesel was prepared from Cleome viscosa plant oil a new feedstock for biodiesel production which is a seasonal plant growing almost in all parts of India. The biodiesel produced from Cleome viscosa methyl ester (CVME) was subjected to various testing in conventional direct injection CI engine using different blends B100, B80, B60, B40, B20 and diesel for performance, combustion and emission analysis to prove its suitability for substituting diesel. It has been observed that a reduction in green house gases like CO and HC to an extent of 30% and 20% respectively, but the BSFC was increased by 5.4% and a reduction in BTE of 4.7% was noted. The biodegradability with the environmental sustainable nature of Cleome viscosa will prefers it as a suitable biodiesel to substitute diesel. [ABSTRACT FROM AUTHOR]

Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) method was used to comprehensively evaluate performance and emission characteristic of DI diesel engine with fumigation gasoline under different engine operating conditions. Diesel and B20 fuel were considered as baseline fuels and gasoline was inducted as fumigation in intake manifold at two different ratio, so that at each operation point, six cases of fuel were tested. The experimental results showed that gasoline fumigation method for both baseline fuels of diesel and B20 results in a significant increase in UHC and CO emissions, and decrease in exhaust gas temperature, smoke opacity and NO and CO 2 emissions. Also, gasoline fumigation increased the brake thermal efficiency at medium and higher loads to about 5% for diesel baseline fuel, while the brake thermal efficiency decreased slightly in case of the B20 baseline fuel with gasoline fumigation. Moreover, the using B20 as an alternative fuel to diesel fuel in modes of with fumigation gasoline reduced the UHC and CO emissions, smoke opacity, exhaust gas temperature respectively to about 20.5%, 16.4%, 9% and 1.1% on average throughout engine loading. While, NO emission of B20 was up to 5% higher than diesel at modes with fumigation gasoline. Finally, all criteria of performance and emission were considered and the evaluation process done to obtain final ranking and choosing the best alternative or the best combination of fuel. From the analytical results it was determined that case of B20 with fumigation gasoline results in desirable performance and minimum emissions at some operation points. [ABSTRACT FROM AUTHOR]

Alcohol fuels offer opportunities to reduce the use of fossil fuels in CI engines and to increase percentage of biofuels in the transport and energy sectors, where combustion engines are often used. This study presents experimental examinations of a stationary single-cylinder compression ignition dual-fuel engine based on co-combustion of diesel fuel with alcohols. The study evaluated the effect of addition of methanol, ethanol, 2-propanol and 1-butanol to diesel fuel on the combustion process, performance and emissions from a research engine. Percentage of the energy supplied in the alcohol fuel was 15, 30, 45, 55 and 70% of total energy supplied with fuel to the engine. The results of the examinations were compared to the examinations for the engine fuelled with pure diesel fuel as a reference. Addition of alcohol to diesel fuel had a positive effect on the level of mean indicated pressure, thermal efficiency and stability of the research engine. The increase in energy percentage of each alcohol to 55% during co-combustion with diesel fuel led to the mean increase in indicated mean effective pressure (IMEP) by 22%, mean increase of indicated thermal efficiency (ITE) by almost 13% and reduction in coefficient of variation COV IMEP by 52%. Of the alcohols analysed in the study, methanol was the most beneficial in terms of high indicated pressure and high efficiency, with maximal values of IMEP = 0.86 MPa and ITE = 35.3% at DM55. Addition and increase in percentage of each alcohol to 55% led to the increase in emissions of nitrogen oxides (by 139% on average), decline of carbon oxide emissions (by 45% on average) and increase in carbon dioxide emissions (by 17% on average). However, it did not lead to significant changes in emissions of hydrocarbons. The highest content of NO x , CO and CO 2 in engine exhaust were found for co-combustion of diesel fuel with addition of methanol. [ABSTRACT FROM AUTHOR]

Numerical study of energetic and emission characteristics of HCCI engine operating on iso-octane based fuel blends comprising hydrogen or syngas as additives is conducted on the basis of 2D CFD simulation for two values of fuel-to-air equivalence ratio ϕ = 0.4 and 0.2. The features of combustion are analyzed for the case when the maximal mass-average temperature ( T ev ) max during the combustion of different fuels is realized at an identical crank angle, which can be implemented at adequate intake temperature for every fuel blend. It is shown that the addition of H 2 or syngas retards the ignition and decreases the combustion duration. This effect is more pronounced for leaner mixture with ϕ = 0.2. The admixture of H 2 to iso-octane leads to the increase of the specific indicated work both for ϕ = 0.2 and ϕ = 0.4. The opposite tendency is detected when syngas H 2 /CO = 2/1 is added to iso-octane. The total emission index EINO x  + EICO is determined mostly by the emission of NO x at ϕ = 0.4 and by the emission of CO at ϕ = 0.2. At ϕ = 0.4, the replacement of iso-octane by iso-octane/hydrogen(syngas) blend increases the NO x emission index (by 86% for iso-C 8 H 18 /H 2  = 20/80 blend), which occurs due to the growth of maximal temperature in the cylinder. At ϕ = 0.2, the addition of H 2 or syngas decreases the emission indices of CO, unburned hydrocarbons, and organics. The higher is the H 2 amount in the blend, the more significant is the effect. The emission indices of NO 2 and N 2 O, in this case, are essentially higher than that of NO. As N 2 O is a very harmful gas, its emission should be taken into consideration when evaluating the total emission of the engine at low load regimes. [ABSTRACT FROM AUTHOR]

A study was conducted to compare gasoline with the addition of 5% by volume of biodiesel (GB05) to 100% neat diesel using the multiple injection strategies in a gasoline compression ignition (GCI) engine. The engine was tested at 1200 rpm using 70 MPa of injection pressure and multiple injections, which consisted of a pilot injection at the 350-degree crank angle before top dead center (°C A BTDC) for approximately 1140 μs, followed by the main injection at 40 °C A BTDC for around 350 μs. The results show that low-temperature combustion can be achieved for GB05 with multiple injections at an in-cylinder temperature of approximately 1800 K. The heat release rates (HRR) for multiple injections of GB05 were lower than that for a single injection of 100% diesel. However, it is higher than those of multiple injections of 100% diesel and a single injection of GB05. Using multiple injections and increasing the temperatures of the intake, oil and engine coolant could result in improved combustion and engine efficiency. Multiple injections of GB05 showed decreased carbon monoxide (CO) emissions, which could be due to the pilot injection of GB05. The biodiesel content and using gasoline as a highly volatile fuel in GB05 showed the significant effect of lowering total hydrocarbon (THC) and CO emissions. However, nitrogen oxide (NOx) emissions from GB05 for both the multiple and single-injection modes seem to be higher than those of multiple injections of 100% diesel and even higher than those of a single injection of 100% diesel, which is due to the oxygen content in the GB05 fuel. [ABSTRACT FROM AUTHOR]

In this research, experimental investigation was undertaken to find the effects of air swirling on pollutant emissions in a cylindrical combustion chamber fuelled with diesel-biodiesel-ethanol blends. At the first, a burner system with various radial air swirl generator (the vane angles were 15°, 25°, 35°, 45°, 60° and 90°) attached to the combustion chamber of 400 mm inside diameter and 2000 mm length. Fuel blends were D100, D85B10E5 (85% diesel, 10% biodiesel and 5% Ethanol on a volume basis), D80B10E10, D75B20E5, and D70B25E5. CO, HC, CO 2 and NOx as the emission characteristics were determined in this research. Moreover gas temperature in a cylindrical combustion chamber was reported. According to the results, the minimum CO and HC emissions belong to fuel blend D70B25E5 and air swirl generator with the vane angles of 15° and the maximum CO and HC emission occurs for net diesel (D100) and swirl air vane angle of 90°. Moreover, D80B10E10 has the maximum CO 2 emission. It shows that ethanol can more effective to increase in CO 2 values than that of biodiesel. Besides, the minimum CO 2 emission obtained for fuel blend D100. The minimum value of NOx emission occurs for D100 and swirl air vane angle of 45°. In addition, air swirling condition with higher vane angles of 45° leads to higher premixed combustion and temperature and causes an increase in NOx emission. Moreover, the maximum value of NOx emission will be for D70B25E5 because of higher biodiesel content as an oxygenated fuel. The results indicated that the mean temperature of combustion gas increases when biodiesel content of fuel mixture increases. On the other hand, the mean temperature of combustion gas decreases by the addition of ethanol in fuel mixture. [ABSTRACT FROM AUTHOR]

The objective of this study is to apply neat biomass fuel to a DI diesel engine and investigate the effect of in-cylinder gas flow and combustion on the deposit formation and the fuel dilution in lubricating oil. The study focuses on the low load combustion and emissions considering that low load exhaust contain much unburned fuels and the unburned fuels are the source of the deposit formation and the fuel dilution. Piston configuration and swirl velocity were altered in the engine test. The engine was fueled by neat rapeseed oil. The test was carried out through the four hours continuous engine operation with keeping low load. After the operation, state of deposit formation and fuel dilution in lubricating oil were investigated. Results indicate that Re-entrant piston which creates strong reverse squish and high swirl forms the deposit annular on the piston top. Toroidal piston easily produces deposit on the undersurface of cylinder head. The deposit in the cavity accumulates where initial rapeseed oil spray impinges regardless of piston types. The carbonization of the deposit is promoted on the wall surface where the burned gas with high temperature and high velocity comes into contact. It is important to avoid extremely strong reverse squish to the cylinder liner in order to control the fuel dilution. The deep-bowl chamber changes the direction of reverse squish from the cylinder liner direction to the cylinder head direction. The low velocity outflow from the piston cavity reduces the adhesion of unburned fuel on the cylinder liner, resulting in the smaller amount of unburned fuel scraped off by a piston ring. [ABSTRACT FROM AUTHOR]

Petroleum-based fuels have been one of the most in demand energy source for various purposes and application. However, rigorous emissions from petroleum-based fuels have forced many governments to introduce stringent regulations and concerns over energy security. Alternative fuel such as short-chain alcohol (methanol and ethanol) had been used as an oxygenated element to increase oxygen content in diesel fuel (DF). However, short-chain alcohol-diesel blends have disadvantages such as low cetane number, low heating value, increase of hydrocarbons (HC) and low miscibility with DF. Recently, researchers have shown interest on long-chain alcohols which have better physicochemical properties than short-chain alcohol. In this experiment, 5%, 10% and 20% of 2-ethyl 1-hexanol (2-EH) was added into DF to produce long-chain alcohol-diesel fuel blends. The fuel blends were prepared by using Hielscher UP400S ultrasonic emulsifier machine at 20% Hz stirring speed. The discussion will focus on combustion characteristics, engine performance and exhaust emissions of single cylinder diesel engine YANMAR TF120M at constant engine speed of 1800 rpm under various loads (0%, 25%, 50%, 75%, and 100%). The results show that HE5 has the preeminent properties among fuel blends in terms of calorific value (45.87 MJ/kg), density (806.1 kg/m 3 ) and viscosity (3.02 mPa·s). Performance analysis shows BTE had increased by 91.72%, while BSFC had decreased by 45.22% for 5% 2-EH (HE5). [ABSTRACT FROM AUTHOR]

Commercialization and effective use of biodiesel is still unattained due to its poor cold storage property. Biodiesel produced from waste cooking oil (WCO) using methanol was blended with 0%, 80% and 90% petroleum-based diesel (PBD) fuel and 20 ppm, 30 ppm, 40 ppm and 50 ppm of magnesium oxide (MgO) nanoparticles. The test fuels quality was found to be within limits of the ASTM standards. 30 ppm concentration of MgO nanoparticles showed improvement in cloud point (CP), cold filter plugging point (CFPP) and pour point (PP) of the test fuels. The results showed that the brake specific fuel consumption (BSFC) of B100W30A, B20W30A and B10W30A fuels were 28.2%, 9.48%, and 2.45% higher than the B100, B20 and B10 fuel respectively. PBD showed lower BSFC but higher brake power (BP) and brake thermal efficiency (BTE) when compared to the other test fuels. The BTE and BP of the B100W30A, B20W30A and B10W30A fuels were 4.57% and 1.17% on an average higher than those of B100, B20 and B10 respectively. In general, MgO nanoparticles blended fuel released relatively lesser emissions than B100, B20, B10 and PBD. Combustion analysis of nanoparticles blended fuel was better than other test fuels and comparable with PBD. [ABSTRACT FROM AUTHOR]

Influence of biodiesel-diesel fuel blends with acetylferrocene and palladium based additives on diesel engine performance and emissions were studied experimentally. The additives were dosed into the blend fuels as 25 ppm. Bis-[ N , N -dimethyl- N ′-2-chlorobenzoylthioureato] palladium (II), PdL 2 was prepared as palladium based additive. The engine tests were carried out in a single cylinder direct injection diesel engine at 4, 8, 12 and 16 Nm loads. The result of engine test revealed that the blend fuels with additives did not show the considerable effect on variation of cylinder pressure values. Also, specific fuel consumption (SFC) values with Ferrocene based additive showed comparatively better results than those of palladium based additives. Furthermore, CO and PM emissions decreased significantly up to 60.07% and 51.33%, respectively. Besides, at higher loads, NO x emissions values of the blend fuels increased, but decreased at lower loads. Moreover, Sound Pressure Level (SPL) and vibration acceleration values with the blend fuels decreased by 2.76% and 18.26%, respectively. As results, using of the metal based additives with dosage of 25 ppm contributed to improvement of SFC, emissions and vibration values for the diesel engines. [ABSTRACT FROM AUTHOR]

In this study, the combustion and emission characteristics of a turbocharged GDI engine under cold start NEDC were investigated based on chassis dynamometer test. The operating states, combustion and emission performance of GDI engine were measured continuously during vehicle driving cycles. Then, the combustion and emission characteristics of GDI engine under cold start NEDC were obtained and the influence factors were revealed by synchronous analysis of various operating parameters. The results show that, the combustion duration from start of combustion (SOC) to 50% combustion location changes a little under cold start NEDC. At most time, the 10–90% combustion duration usually changes in the range of 20–40 °CA, which turns longer under idling conditions but shorter under acceleration conditions. Since the sparking timing is severely retarded in the beginning stages of NEDC, the effect of cold start on hydrocarbon (HC) emission is very limited. HC emission increases sharply under deceleration conditions, due to the decrease of engine indicated mean effective pressure (IMEP). Carbon monoxide (CO) emission does not seem to have relevance to the cold start condition, and it is very sensitive to excess air coefficient while the effects of other parameters are very little. Nitrogen oxide (NOx) emission increases under acceleration conditions but decreases under deceleration conditions, which is mainly influenced by the IMEP, then followed by engine speed. All those not only demonstrated the change rules of combustion and emission characteristics of turbocharged GDI engine under cold start NEDC, but also provided the guidance for improving the vehicle emission performance. [ABSTRACT FROM AUTHOR]

Coal-fired power plant is considered to be main anthropogenic emitter for emission of hazardous trace elements (HTEs), which can cause great damage on environment and human health. Emission characteristic of nine HTEs, namely Hg, Zn, Sb, Pb, Cd, As, Cr, Mn and Ba was carried out on a 320 MW coal-fired power plant equipped with SCR, ESP and WFGD. US EPA method 29 was used for flue gas HTEs sampling at inlet or outlet of each APCD simultaneously. Solid or liquid samples like feed coal, ESP ash, bottom ash, fresh slurry, waste water, gypsum were collected at the same time. Scanning electron microscope, energy dispersive spectrometer and X-ray power diffraction spectrometry were adopted to characterize the physical and chemical structure characteristic of some solid samples. Results show that mass balance rate of the HTEs for each device and the system is in acceptable range. Mass amount of HTEs distributed in bottom ash and ESP ash accounts for large proportion, while little of them escapes into atmosphere (<0.05%). The mass amount of Mn and Ba in bottom ash is higher than that of other HTEs. Particulate HTEs are the main form in flue gas before ESP. ESP + WFGD has high removal efficiency for the HTEs in flue gas (99.96–99.99%), in which ESP makes a great contribution. During coal combustion, Mn and Ba enrich in bottom and fly ash equally while As, Cd, Sb, Zn, Pb and Cr will be prone to enrich in fly ash. Concentration of the HTEs in flue gas emitted to atmosphere is relatively low (3.5 × 10 −3 –4.30 μg/m 3 ) with emission factor of 0.001–1.473 g/10 12 J. Finally, transformation mechanism of the studied HTEs during coal combustion is discussed. [ABSTRACT FROM AUTHOR]

Predicted scarcity of conventional fuels and their increasing cost have given rise to interest in alternative fuels like biofuels, ethyl alcohol, methyl alcohol, hydrogen, producer gas, acetylene etc. in order to meet the energy requirement. Gaseous fuels are good for clean burning, but are costly. In the present study, a single cylinder, four strokes, direct injection, vertical, water cooled, variable compression ratio, multi fuel engine was used to operate in dual fuel mode. In this experiment acetylene was inducted at a flow rate of 7 lpm at various compression ratios of 18:1, 18.5:1, 19:1 and 19.5:1. Results were evaluated and compared on the basis of combustion, performance and emission parameters. Peak cylinder pressure and brake thermal efficiency are found to increase whereas exhaust gas temperature decreases with increase in compression ratio. The brake thermal efficiency was found to be maximum (21.18%) at 19.5:1 compression ratio. [ABSTRACT FROM AUTHOR]