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In this study, the nanostructure, surface functional groups, and oxidation activity of soot particulate along the exhaust after-treatment system of a heavy-duty diesel engine fueled with waste cooking oil (WCO) biodiesel blends are investigated by TEM, XPS, and TGA respectively. The main findings are as follows: Along the exhaust after-treatment system, fringe length of primary particles of soot particulate emitted from tested heavy-duty diesel engine fueled with B0, B10, B20, and B100, i.e., 0%, 10%, 20%, and 100% ratio of WCO biodiesel blended into petroleum diesel in volume respectively increases, while fringe tortuosity and separation distance of primary particles reduces. The fringe length of B10, B20, and B100 is smaller, but the fringe tortuosity and separation distance are larger than that of B0. The O/C ratio of soot particulate tends to increase firstly and then decrease as the exhaust passes through DOC+cDPF and SCR+ASC in sequence. The O/C ratio of B10, B20, and B100 are also higher than that of B0. Soot particulate at cDPF outlet contains carborundum and biuret is found at SCR+ASC outlet. The sp3/sp2 ratio decreases along the exhaust after-treatment system, and B10, B20, and B100 tend to get higher sp3/sp2 ratio than B0. The C–OH and C=O content of soot particulate from different WCO biodiesel blends show generally similar trends along the exhaust after-treatment system, while the activation energy of soot particulate keeps increasing along the exhaust after-treatment system, but decreases with the increasing of blend ratio. These findings can provide useful references for optimizing the after-treatment system for WCO biodiesel blends. [ABSTRACT FROM AUTHOR]

This review study was created from the various studies which were completed on the use of dimethyl ether (DME) in diesel engines as a fuel or fuel additive. The several methods are available for the decreasing of the harmful emissions in diesel engines. The first method for the reduction of harmful emissions is improved the combustion by modification of engine design and fuel injection system, but this process is expensive and time consuming. The second method is the using various exhaust gas devices like catalytic converter and diesel particulate filter. However, the use of such devices affects negatively diesel engine performance. The last method to reduce emissions and also improve diesel engine performance is the use of various alternative fuels or fuel additives. The major pollutants of diesel engines are oxides of nitrogen (NOx) and particulate matter (PM). It is very difficult to reduce NOx and PM simultaneously in practice. The most researches declare that the best way to reduce these emissions is the use of various alternative fuels i.e. natural gas, biogas, biodiesel or using some additives with the alternative fuels or conventional diesel fuel. Therefore, it is very important that the results of various studies on alternative fuels or fuel additives are evaluated together to practice applications. Especially, this study focuses on the usage of dimethyl ether in diesel engines as fuel or fuel additive. This review study investigates the effects of using dimethyl ether on particulate matter (PM) emissions. As a result of this review study; it was determined that when DME is used in pure form, it provides nearly zero PM emission due to its features such as high oxygen content, the absence of directly bonded carbon in its chemical structure, rapid evaporation, high cetane number and low ignition temperature. It was determined that pure DME was found to reduce the PM emissions by 13-228% compared to diesel fuel and 88.6-227.6% compared to biodiesel fuel. It was also determined that diesel-DME blends containing different ratios of DME reduced the PM emissions by 4.7-509% compared to diesel fuel, and biodiesel-DME blends containing different ratios of DME reduced the PM emissions by 38.2% compared to biodiesel fuel. On the other hand, it was determined that the LPG-DME blend decreased the PM emissions by 269-493% compared to diesel fuel, and the DME-NH3 blends containing different amounts of DME increased the PM emissions by 40.7-96.7% compared to pure DME. Moreover, it was determined that changing the exhaust gas recirculation (EGR) ratio between 10-50% increased PM emissions by 13.1-48.4%. [ABSTRACT FROM AUTHOR]

To evaluate the Influence of polyoxymethylene dimethyl ethers (PODE) on particulate matter (PM) chemical features, PM samples emitted from diesel fuel and PODE/diesel blends at volume ratios of 10 %, 20 %, and 30 % (P10, P20, and P30) were characterized using gas chromatography-mass spectrometry, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopic (FT-IR). Results showed that adding PODE in diesel fuel could increase the proportions of the lower carbon-atom-number components and the contents of oxygen-containing compounds in the soluble organic fractions extracted from PM samples. The ratio of oxygen to carbon (O/C), the functional groups, and the nanostructure of dry soot obtained from XPS showed that the O/C rose as the PODE volume ratio increased. The graphitization degree of dry soot decreased in the order: diesel fuel > P10 > P30 > P20. The relative content of hydroxyl functional groups exhibited the same trend, while the relative content of carbonyl functional groups exhibited an opposite trend with the graphitization degree. Moreover, according to FT-IR, both the branching degree and the relative content of hydrocarbon functional groups of aliphatics are influenced by the graphitization degree of dry soot. A turning point at P20 observed by analysis results above indicated that the chemical characteristics of PM could be affected not only by fuel properties but also by the process of fuel combustion and PM formation. [ABSTRACT FROM AUTHOR]

Different from vehicle engines, Diesel Particulate Filter (DPF) inactivation is an unavoidable issue for low-speed marine diesel engines fueled with Heavy Fuel Oil (HFO). This paper introduced a sulfur resisting material in Silicon Carbide (SiC)-DPF to improve DPF performance. The results of bench-scale experiments showed that the Balance Point Temperature of the modified DPF module was 300°C and DPF modules had a good filtration performance, with Particulate Matters (PMs) residual being less than 0.6 g per cycle. In pilot-scale tests, PMs emissions of unit power decreased with engine load going up, filtration efficiency of nucleation mode PMs being only 36% under 100% load, while DPF still had a good performance in accumulation mode PMs control, being 94.2% under the same load. DPF modules showed excellent regeneration durability in the 205h endurance test, with a regeneration period of 1.5-2h under 380°C. There was no obvious degeneration in the DPF module structure, with no cracks or breakage. Besides, the DPF module could also control gaseous emissions, total emissions decreased by 10.53% for NO and 57.19% for CO, respectively. The results suggested that introducing sulfur-resisting material in DPF could greatly improve the DPF performance of low-speed marine diesel engines fueled with HFO. [ABSTRACT FROM AUTHOR]

This review study was created from the various studies which were completed on the use of dimethyl ether (DME) in diesel engines as a fuel or fuel additive. The several methods are available for the decreasing of the harmful emissions in diesel engines. The first method for the reduction of harmful emissions is improved the combustion by modification of engine design and fuel injection system, but this process is expensive and time consuming. The second method is the using various exhaust gas devices like catalytic converter and diesel particulate filter. However, the use of such devices affects negatively diesel engine performance. The last method to reduce emissions and also improve diesel engine performance is the use of various alternative fuels or fuel additives. The major pollutants of diesel engines are oxides of nitrogen (NOx) and particulate matter (PM). It is very difficult to reduce NOx and PM simultaneously in practice. The most researches declare that the best way to reduce these emissions is the use of various alternative fuels i.e. natural gas, biogas, biodiesel or using some additives with the alternative fuels and conventional diesel fuel. Therefore, it is very important that the results of various studies on alternative fuels or fuel additives are evaluated together to practice applications. Among the various alternative fuels, oxygenated fuels draw a great attention. DME is very suitable fuel for diesel engines due to its oxygen content, high cetane number and other desired fuel properties. Therefore, the presented review study focuses on the usage of DME in diesel engines as a fuel or fuel additive. This review study investigates the effects of using DME on hydrocarbon (HC) emissions. [ABSTRACT FROM AUTHOR]

The problem of environmental pollution by the combustion of fossil fuels in diesel engines, to which NOx emission is a dominant culprit, has accelerated global environmental pollution and global and local health problems such as lung disease, cancer, and acid rain. Among various De-NOx technologies, SCR (Selective Catalytic Reduction) systems are known to be the most effective technology for actively responding to environmental regulations set by the IMO (International Maritime Organization) in marine diesel applications. The ammonia mixes with the exhaust gas and reacts with the NOx molecules on the catalyst surface to form harmless N2 and H2O. However, since the denitrification efficiency of NOx can be rapidly changed depending on the operating temperature from 250 °C to 350 °C at 0.1% sur contents of the catalyst used in the SCR, a device capable of controlling the exhaust gas temperature is essential for the normal operation of the catalyst. In addition, when the catalyst is exposed to SOx in a low exhaust gas temperature environment, the catalyst is unable to reduce the oxidation reaction of the catalyst, thereby remarkably lowering the De-NOx efficiency. However, if the exhaust gas temperature is set to a high temperature of 360–410 °C, the poisoned catalyst can be regenerated through a reduction process, so that a burner capable of producing a high temperature condition is essential. In this study, a plasma burner system was applied to control the exhaust gas temperature, improving the De-NOx efficiency from the engine and regenerating catalysts from PM (Particulate Matter), SOOT and ABS (ammonia bisulfate), i.e., catalyst poisoning. Through the burner system, the optimum De-NOx performance was experimentally investigated by controlling the temperature to the operating region of the catalyst, and it was shown that the regeneration efficiency in each high temperature (360/410 °C) environment was about 95% or more as compared with the initial performance. From the results of this study, it can be concluded that this technology can positively contribute to the enhancement of catalyst durability and De-NOx performance. [ABSTRACT FROM AUTHOR]

Harmful substances, such as particulate matter (PM), nitrogen oxides, and sulfur compounds in exhaust gas emitted from marine diesel engines have a great impact on the air environment. Among them, especially black carbon in PM has a negative effect on global warming. The exhaust gas from marine diesel engines using fuels containing heavy fuel oil has a high PM concentration and high temperature. Therefore, a commonly used diesel particulate filter is not suitable for collection because it tends to cause clogging and reduce efficiency. Furthermore, it is often the case that ships are at sea for more than one month, so it is difficult to replace the filter, that is, maintenance is difficult. On the other hand, an electrostatic precipitator (ESP) has the advantages of a simpler structure, lower pressure loss, and higher collection efficiency of high concentration particles. This suggests that the ESP is suitable for collecting harmful substances from the marine diesel exhaust gas. At high temperatures, corona discharge is unstable, and a flashover tends to occur at low applied voltage. Therefore, it is necessary to study the stable corona discharge generation range for the stable operation of the ESP. The purpose of this research is to analyze the optimal electrode structure and its corona discharge characteristics under the simulated exhaust gas of a diesel engine in the range of 100 °C – 400 °C using a negative dc power supply. [ABSTRACT FROM AUTHOR]

Aiming to investigate the impacts of n -octanol addition on the oxidation reactivity, morphology and graphitization of diesel exhaust particles, soot samples were collected from a four-cylinder turbocharged diesel engine fueled with D100 (neat diesel fuel), DO15 (85% diesel and 15% n -octanol, V/V) and DO30 (70% diesel and 30% n -octanol, V/V). All tests were conducted at two engine speeds of 1370 and 2150 r/min under a fixed torque of 125 N·m. The soot properties were characterized by thermogravimetric analyzer (TGA), transmission electron microscopy (TEM) and Raman spectroscopy (RS). The higher volatile organic fraction content, lower soot oxidation temperatures and lower activation energy from TGA results indicated that both the increasing n -octanol concentration and engine speed enhanced the soot oxidation reactivity. Additionally, quantitative analysis of TEM images showed that the soot derived from DO30 had the smallest primary particle diameters and fractal dimension, followed by those of soot produced by DO15 and D100. The RS results demonstrated that the n -octanol addition and higher engine speed led to a larger D1-FWHM (D1-full width at half maximum), A D1 /A T (area ratio of D1 band and the total spectral) and A D3 /A T (area ratio of D3 band and the total spectral) as well as a smaller L a (crystallite width), revealing a lower degree of graphitization. Furthermore, the correlations between characterization parameters of soot properties and reactivity were nonlinear. [Display omitted] [ABSTRACT FROM AUTHOR]

We studied ice-nucleating abilities of particulate emissions from a modern heavy-duty diesel engine using three different types of fuel. The polydisperse particle emissions were sampled during engine operation and introduced to a continuous-flow diffusion chamber (CFDC) instrument at a constant relative humidity RH water=110 %, while the temperature was ramped between -4 3 and -32 ∘ C (T scan). The tested fuels were EN 590 compliant low-sulfur fossil diesel, hydrotreated vegetable oil (HVO), and rapeseed methyl ester (RME); all were tested without blending. Sampling was carried out at different stages in the engine exhaust aftertreatment system, with and without simulated atmospheric processing using an oxidation flow reactor. In addition to ice nucleation experiments, we used supportive instrumentation to characterize the emitted particles for their physicochemical properties and presented six parameters. We found that the studied emissions contained no significant concentrations of ice-nucleating particles likely to be of atmospheric relevance. The substitution of fossil diesel with renewable fuels, using different emission aftertreatment systems such as a diesel oxidation catalyst, and photochemical aging of total exhaust had only minor effect on their ice-nucleating abilities. [ABSTRACT FROM AUTHOR]

Accurate measurement of diesel volume is important in both industrial and domestic applications. The accuracy of volume evaluation of diesel fuel is affected by the formation of bubbles in diesel. In this paper, the authors have studied the volume of bubbles generated in diesel in the process of transportation and the change in the volume of the bubbles with time. They measured the volume of diesel in the metal tank (1·107 mm3) and the metal tank volume (5·107 mm3) under different temperature conditions. The volume proportion of bubbles generated in diesel in the process of transportation is quantitatively analyzed. The results show that the bubble volume changes with time in accordance with an exponential function, and the convergence value of the bubble volume ratio is –3.16356·10–4. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of lubricating oil age on the generation of diesel particulate filters (DPF) by non-thermal plasma (NTP) technology and to characterize the physical properties of ash. The regeneration status was evaluated by the concentration of regeneration products and regeneration temperature. The compositional and morphological characteristics of ash were analyzed by energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Compared with DPF@L-fresh, the internal regeneration temperature was reduced in DPF@L-age. The unit removal time of carbon was 39.23 min/g for DPF@L-fresh but was reduced to 34.87 min/g for DPF@L-age, which indicated that the efficiency of NTP regeneration increased. Shorter regeneration time and lower airflow resistance caused by NTP technology aided the formation of a unique chain-type ash with the structure of a hollow column. Several fine particles that had formed by the condensation of volatiles were distributed on the ash surface of the aged lubricant, and the ash clusters were loosely combined. TEM images revealed that ash was mostly composed of a crystal structure, that the ash dimension of aged lubricant decreased, and that the adhesion between ash particulates was weak. [ABSTRACT FROM AUTHOR]

Experiments were conducted on a single-cylinder four-stroke diesel engine coupled to an eddy current dynamometer. In the first approach, baseline data generation for optimization of injection timing, injection pressure, number of holes, and combustion chamber types was done. Further, exhaust gas recycle (EGR) was added at the rate of 5%, 10%, 15%, and 20% to these optimized diesel engine operating parameters. Adopting diesel particulate filter (DPF) and diesel oxidation catalyst (DOC), NOx emission was measured. In the second approach, test runs were conducted on diesel engine by injecting 5%, 10%, 15%, and 20% diethyl ether (DEE). EGR, DPF, and DOC were adopted to reduce NOx. In the third approach, experiments were conducted by injecting DEE into inlet manifold at injection timings, viz., 5°BTDC, TDC, 5°ATDC, and 10°ATDC and with injection duration of 18°, 22.5°, 27°, 31.5°, and 36° CA. The 20% EGR, DPF, and DOC were fixed when manifold injection of DEE to observe the further reduction in NOx level. The first approach resulted in the highest brake thermal efficiency of the engine and was found to 31.25% and 27.36% without EGR and with 20% EGR. Lowest smoke and CO levels obtained were 11 ppm and 0.094% with both DPF and DOC. Reduction of NOx by 25% was achieved by combined mode of EGR, DPF, and DOC. The second approach resulted in a brake thermal efficiency of 29.25% and was obtained when the engine was powered with 20% DEE. With 20% EGR, HC and CO reduced by 40% and 8% adopting DPF and by 10% and 45% adopting DOC. NOx emission reduced by 10% adopting DPF and reduced by 6% using DOC. Finally, in the third approach, a Brake thermal efficiency of 30.84% was obtained with manifold injection of DEE and reduced to 29.3% when 20% EGR was adopted. DPF reduced smoke by 37 HSU and DOC by 1 HSU. Lowest NOx emission of 760 ppm was obtained for engine injecting DEE in manifold having 20% EGR, DPF, and DOC. Comparing results of all the test runs under three approaches, the optimum condition suggested to an existing diesel engine to be fueled with 20% DEE/diesel ratio having 80% load, operating with 20% exhaust gas recirculation rate adopting both DPF and DOC. The performance and emission values at this suggested condition are found to be as brake thermal efficiency of 27.5%, peak pressure 69 bar, ignition delay of 10.2 deg CA, combustion duration of 44 deg CA, smoke of 11 HSU, HC of 33 ppm, CO of 0.16%, and NOx of 680 ppm. [ABSTRACT FROM AUTHOR]

Measuring the size of the informal diesel market is important for determining tax revenue losses and identifying inefficiencies in tax policies. The conventional ways of assessing the informal sector entail either not allowing the measurement of the size of the informal sector across time or assuming a stable relationship between diesel consumption and a set of economic variables. This study assesses the informal sector of the Turkish diesel market by using the Kalman filter method. This method allows unobserved values to be estimated with observed variables. Using monthly interpolated GDP, official diesel consumption, and the number of diesel motor vehicles, Turkey's unobserved informal diesel fuel consumption between January 2005 and February 2020 is estimated. The results obtained with this estimation method reveal that the level of informal diesel consumption increased until 2012–2014; it then started to decline at the end of 2014 and started to increase again after 2018. These dates are associated with periods of economic recession, political developments, and the passing of anti-smuggling legislation. [ABSTRACT FROM AUTHOR]

• Oxygenated functional groups of soot particles increased with increasing OME 3 doping. • An increase in OME 3 blending enhanced soot aliphatic and aromatic C − H groups. • Blending OME 3 altered the spatial distribution of carbon-hybridised orbitals. • Incorporating OME 3 led to higher levels of O and H within the soot particles. Oxymethylene ether-3 (OME 3) is a promising synthetic e-fuel and alternative fuel for diesel engines. In contrast to diesel fuel, the use of OME 3 leads to a distinct combustion process in which soot particles are generated, which leads to changes in the chemical properties of these particles. These chemical properties are intricately connected to both the concentration and availability of potential radical sites, which, in turn, exert a substantial influence on soot oxidation during diesel particulate filter (DPF) regeneration. Hence, it is crucial to investigate the chemical features of soot samples. Nevertheless, a thorough investigation into the chemical features of n -heptane/OME 3 soot samples has not been fully understood. Here, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), elemental analyser, and thermogravimetric analysis (TGA) were used to examine the impact of blending OME 3 on chemical features of soot particles at various flame heights of an inverse n -heptane-OME 3 flame. XPS results from C1s and O1s peaks showed that OME 3 incorporation enhanced the concentrations of C = O, C–O, and O = C–O groups, especially C = O groups, with the percentage increase ranging from 11.93 % to 49.74 %. Similarly, the content of aliphatic C − H groups, along with O and H, increased with higher levels of OME 3 blending. Moreover, it was discovered that blending OME 3 altered the spatial distribution of hybridisation orbitals of carbon atoms, leading to a decrease in the sp2/sp3 ratio by as much as 40 % with the increase in the OME 3 blending ratio. The alteration in these chemical properties due to the addition of OME 3 enhanced the oxidative reactivity of soot particles, as manifested by up to a 15 % reduction in the measured activation energy. These findings are useful to optimise control strategies of DPF regeneration with the more widespread use of e-fuel. [ABSTRACT FROM AUTHOR]

Vehicular emissions deteriorate air quality in urban areas notably. The aim of this study was to conduct an in-depth characterization of gaseous and particle emissions, and their potential to form secondary aerosol emissions, of the cars meeting the most recent emission Euro 6d standards, and to investigate the impact of fuel as well as engine and aftertreatment technologies on pollutants at warm and cold ambient temperatures. Studied vehicles were a diesel car with a diesel particulate filter (DPF), two gasoline cars (with and without a gasoline particulate filter (GPF)), and a car using compressed natural gas (CNG). The impact of fuel aromatic content was examined for the diesel car and the gasoline car without the GPF. The results showed that the utilization of exhaust particulate filter was important both in diesel and gasoline cars. The gasoline car without the GPF emitted relatively high concentrations of particles compared to the other technologies but the implementation of the GPF decreased particle emissions, and the potential to form secondary aerosols in atmospheric processes. The diesel car equipped with the DPF emitted low particle number concentrations except during the DPF regeneration events. Aromatic-free gasoline and diesel fuel efficiently reduced exhaust particles. Since the renewal of vehicle fleet is a relatively slow process, changing the fuel composition can be seen as a faster way to affect traffic emissions. [Display omitted] • This study characterized gas and particle emissions from Euro 6d level cars. • Cars represented various engine and after-treatment techniques and fuels. • Exhaust particle filter diminish particle emissions both in diesel and gasoline car. • Aromatic-free gasoline and diesel fuel efficiently reduced exhaust particles. • Fresh exhaust was significantly contributed by 1.2–10 nm particles. [ABSTRACT FROM AUTHOR]

This study explores the combustion characteristics of a single cylinder four stroke variable compression ratio direct injection diesel engine run by Nahar biodiesel (BD) and its six different blends (B5, B10, B20, B30, B40, and B50). Combustion duration reduced up to B40 and slightly increased for B50 and significantly for B100. Peak cylinder pressure (PCP) increased with BD concentration in the blend. Maximum rate of pressure rise (MROPR), heat release rate, and ignition delay (ID) reduced with an increase in BD share in the blend. At full load, PCP for B100 is obtained as 70.91 bar, whereas for diesel it is 70.04 bar. The MROPR is observed to be 5.67 bar/°CA for diesel, whereas 5.31 bar/°CA for B100 at full load. Peak heat release rate is observed to be 64.7 J/°CA for diesel, whereas it is 54.41 J/°CA for B100. ID for the blends reduced by 1–2°CA compared to diesel fuel. Overall, it is recommended to use BD up to B40 blend in a DI diesel engine primarily employed in gen sets and agricultural units. Abbreviation: BD: Biodiesel; DF: Diesel fuel [ABSTRACT FROM AUTHOR]

Today, vehicles especially diesel engines emitted a large amount of NOx in the urban areas. So, it is required to find ways such as SCR catalysts to reduce this hazard pollutant emission. In this work, a 3D model of cordierite/Pt SCR catalyst has been developed by using AVL FIRE software to analyze the NOx conversion efficiency. The simulation was performed based on experimental tests conducted on a single-cylinder engine. The exhaust gas from the engine that appears at the inlet of the catalyst was measured for E20B50D30 (20% ethanol, 50% biodiesel, 30% diesel) D100, E10D90, E20D80, B25D75 and B50D50 fuel blends at the engine speeds of 1800, 2150 and 2500 rpm under full load. The results showed that an increase in the engine's rotational speed resulted in a reduction of NOx conversion, and the conversion rate reaches its minimum value at speed of 2500 RPM for all fuel mixtures. Moreover, increasing the ammonia mass flow rate resulted in higher NOx conversion for all fuel mixtures. However, the effect of increasing ammonia flow rate from 0.2 to 0.3 kg/h on the NOx conversion is lower than that when the ammonia mass flow changes from 0.1 to 0.2 kg/h. The maximum NOx conversion rate was observed for the mixture containing 20% ethanol and 80% diesel at the rotational speed of 1800 RPM while the lowest conversion rate is observed for pure diesel fuel. According to the results, it was seen that the SCR catalytic process for fuel blends contained ethanol have a better performance to reduce the NOx pollutant compared to the mixtures containing biodiesel at lower engine speeds; but at higher rotational speeds ethanol and biodiesel has not a positive effect on the NOx conversion. [ABSTRACT FROM AUTHOR]

RCCI as low temperature combustion is one of the common methods for reducing nitrogen oxides and soot pollutants. In this study, the effect of exhaust gas recirculation on combustion and emission of an RCCI engine, fueled with diesel and CNG was investigated. The investigated engine is a single-cylinder engine with diesel direct injection to the combustion chamber as high-reactivity fuel and a port fuel injection of CNG fuel as low-reactivity fuel. The start of injection, the injection shape, and the injection duration of both injectors are controlled by the developed ECU. Since the engine tested has good stability in the premix ratio of 60% and is capable of operating with high EGR percentage, it was selected for investigation. The results of this study show that with an increase of the exhaust gas recirculation rate from 0 to 34%, the amount of IMEP and thermal efficiency decrease by about 18%. As the EGR increases, the start, middle, and end of the combustion are delayed due to the decrease in oxygen content inside the combustion chamber. With the increase of EGR, the temperature of the combustion chamber decreased so that increasing CO and UHC production, showing an increase of 86 and 300%, respectively, while NOx decreases by 350%. [ABSTRACT FROM AUTHOR]

Depletion of fossil fuels and stringent emission norms focus attention to discover an evitable source of alternative fuel in order to attribute a significant compensation on conventional fuels. Besides, waste management policies encourage the valorization of different wastes for the production of alternative fuels in order to reduce the challenges of waste management. In this context, pyrolysis has become an emerging trend to convert different wastes into alternate fuel and suitable to be used as a substitute fuel for CI engines. The current investigation provides a sustainable and feasible solution for waste plastic management by widening the gap between global plastic production and plastic waste generation. It investigates the performance and emission of a single cylinder DI four stroke diesel engine using waste plastic oil (WPO) derived from pyrolysis of waste plastics using Zeolite-A as catalyst. Engine load tests have been conducted taking waste plastic oil and subsequently a blend of waste plastic oil by 10%, 20%, and 30% in volume proportions with diesel as fuel. The performance of the test engine in terms of brake thermal efficiency is found marginally higher and brake specific fuel consumption comparatively lowest for 20% WPO-diesel blend than pure diesel. The NOx and HC emission is found lower under low load condition and became higher by increasing the load as compared to diesel. Fuel exergy was significantly increasing after blending of WPO with pure diesel, but exergetic efficiency of the blended fuels followed the reverse trend. However, increase in load of the engine improved the exergetic efficiency. The 20% WPO–diesel blended fuel is found suitable to be used as an alternative fuel for diesel engine. • Study reports the possibility of utilisation of waste plastic oil in CI engine. • Energy and exergy analysis is the major aspect of the work. • It also reports the emission quality in the utilisation of plastic oil in diesel engine. [ABSTRACT FROM AUTHOR]

The paper presents experimental studies of a dual-fuel diesel engine which was fueled by diesel fuel in to the cylinder and hydrogen to the intake manifold. The effect of co-combustion of hydrogen and diesel fuel on the stability, performance and exhaust gas emission of the test engine was studied. The energy share of hydrogen co-combusted with diesel was changed in the range from 0 (D100) to 30% (DH30). Increasing the hydrogen energy share to 30% in a compression-ignition engine operating at full load resulted in an increase in the maximum combustion pressure (by 13%), the rate of heat release (by 46%) and the rate of pressure rise (by 35%). The addition of hydrogen, due to the increase of the combustion rate and shortening of the total duration of this process, caused an increase in efficiency, by a maximum of 17% for DH14 and DH25. For DH30 there was a significant decrease in engine stability, confirmed mainly by the determined value of the coefficient of covariance in the indicated mean effective pressure. The addition of hydrogen to a compression-ignition engine, up to 25%, resulted in a significant, almost 85% reduction in soot emissions, an almost 57% reduction in carbon monoxide, and an almost 27% reduction in carbon dioxide. The disadvantage of using hydrogen as a fuel for a compression-ignition engine was increase in HC emissions and a significant increase in NO emissions (by over 80% for DH30). • Diesel engine with hydrogen addition. • The effect of hydrogen on stability, performance and emissions in co-combustion with diesel fuel is investigated. • The addition of hydrogen in the diesel engine increases thermal efficiency. • Reduction of soot, CO and CO 2 emissions by hydrogen addition to the CI engine. [ABSTRACT FROM AUTHOR]

In this experimental study, the effects of biodiesel on emissions, performance and combustion characteristics on the passenger car, which provides EURO-5 emission standards with 1.5 liters of diesel engine, were investigated by performing tests on chassis dynamometer. 4 different blends of diesel and biodiesel and pure diesel were used at the experiments. Biodiesel used in the experiments were derive from canola oil. The exhaust emissions, engine sensors' data via the on-board error monitoring port, the in-cylinder pressure and injector current signal of the second cylinder of the engine were continuously measured during the experiments. In order to investigate the effects of biodiesel on the combustion characteristics, the heat release rate, average in-cylinder temperature, start of combustion, ignition delay and combustion duration were calculated by using the indicator diagram. According to the obtained results, biodiesel-added fuel ignites under lower temperature and pressure in-cylinder condition compared to pure diesel. Therefore, addition of biodiesel to diesel reduced the ignition delay duration 2 crank angle and injected fuel burned faster than diesel fuel. Besides, addition of 10% biodiesel additive has improved HC, CO and soot emissions 15%, however fuel consumption increased 2% due to biodiesel's lower calorific values than diesel. Moreover, up to 4% rise in NOx emission were observed with increasing biodiesel blend ratio. In addition, it is found that the fuel used in the regulation tests in the European Union contains 4% more biodiesel compared to the diesel used in Turkiye, and it is found that the light commercial passenger vehicles used in Turkiye emit 10% more emissions compared to the declared CO, HC and soot emissions. [ABSTRACT FROM AUTHOR]

The objective of the present study is to scrutinize the influence of a binary blend of diesel–safflower oil biodiesel and ternary blends of diesel–biodiesel–pentanol on performance, emission and combustion characteristics of a diesel power generator. The test fuels were prepared on volume basis by splash blending and named as follows: B20, B20P5, B20P10, B20P15, and B20P20. The tests were carried out on a single-cylinder, four-stroke, naturally aspirated, and direct-injection diesel engine at four engine loads with a constant engine speed of 3000 rpm. According to the results, ternary blends vaguely reduced BTE while increased BSFC up to 13.90% as compared to diesel. In addition, an increase in pentanol concentration has a considerable effect on the decrease in NOX emissions. It is noted that the addition of pentanol to diesel–biodiesel blend caused to lower emissions (CO, HC, and smoke), whereas CO2 emission increased noticeably thanks to the more complete combustion due to the excess oxygen content. Reviewing combustion analysis results, pentanol addition led to decrease heat release rate and lower ignition delay up to 15% blend ratio compared to diesel. Based on the present study, pentanol can be evaluated as a promising type of higher alcohol for the compression ignition engines in the near future. [ABSTRACT FROM AUTHOR]

In order to make a reasonable control strategy of Reactivity Controlled Compression Ignition (RCCI) combustion mode and to explore the influence of different combustion boundary conditions on the combustion and emission characteristics of RCCI, in this paper, a six-cylinder heavy-duty diesel engine was used to test the RCCI of gasoline / diesel dual fuel under the condition of constant engine speed and gasoline energy Premixing Ratio (PR). The effects and its degree of Start of Injection (SOI) and Inlet Pressure (IP) on gasoline/diesel RCCI combustion and emission characteristics were studied under different Cycle Energy (CE) operating conditions with a fixed gasoline energy PR of 65%. The results indicated that the effects of SOI and IP on all combustion characteristic parameters hardly changed with the increase of CE. For example, the ignition delay increased with the advancement of SOI under different CE. The effects degree of SOI and IP on some combustion characteristic parameters changed with the increase of CE. For example, with the same advancement of SOI (23 °CA), the maximum of cumulative heat release was average increased by about 150 J when CE was 885 J, while the maximum of cumulative heat release was average increased by about 250 J when CE was 1 700 J, the effects degree of SOI on maximum of cumulative heat release became greater with the increase of CE. What’s more, the adjustment range of IP on the peak average temperature in the cylinder was decreased by about 130 K, when CE increased from 885 to 1 700 J, the effects degree of IP on the peak average temperature in the cylinder became greater with the increase of CE, which indicated that the adjustment capacity of IP on the in-cylinder temperature became stronger. However, the effects degree of SOI and IP on some combustion parameters did not change with the increase of CE, such as the effects degree of SOI and IP on the ignition delay, the increase of the ignition delay was almost the same (about 10 °CA) with the advancement of SOI (23 °CA) under different CE. What’s more, the change of thermal efficiency was almost the same (about 5%) with the advancement of SOI (23 °CA) under different CE. Besides, the effects of SOI and IP on the gas emissions, except the CO emission, almost unchanged with the increase of CE. In fact, when CE increased from 885 to 1 700 J, the CO emission decreased continuously. However, the increase of CE changed the effects degree of SOI and IP on some gas emissions, for example, with the same increase of IP by 15 kPa, the HC emission was average increased by about 13.65 g/(kW·h) when CE was 885 J, it remained almost the same with the CE was 1 700 J, that was, the effects degree of IP on the HC emission was greatly reduced with the increase of CE, which indicated that the adjustment capacity of IP on the HC emission became weaker. What’s more, with the same increase of IP from 110 to 125 kPa, the NOx emission was average decreased by about 1 g/(kW·h) when CE was 885 J, while the NOx emission was average decreased by about 4 g/(kW·h) when CE was 1 700 J, that was, the effects degree of IP on the NOx emission was slightly increased with the increase of CE, which indicated that the adjustment capacity of IP on the NOx emission was slightly enhanced. In addition, the increase of CE changed the effects or its degree on some parameters of particles emission. For example, the effects degree of SOI and IP on the average particle size and number concentration of nuclear particles were both decreased with the increase of CE, which indicated that the adjustment capacity of SOI and IP on the nuclear particles became weaker. On the contrary, the effects or its degree of some parameters of particles emission did not change with the increase of CE. For instance, the impact of SOI on the total mass concentration of particles was almost the same under different CE. The research results can provide data support for making a reasonable control strategy of RCCI combustion mode. [ABSTRACT FROM AUTHOR]

In this study, detailed experiments were conducted on the combustion and exhaust characteristics of ethanol–diesel blended fuels. The four-stroke four-cylinder common-rail direct injection diesel engine was used. The experiment was carried out at 750 rpm at a low speed idle, and a 40 Nm engine load was applied to simulate the operation of the accessories during the low idle operation of the actual vehicles. The test fuels were four types of ethanol-blended fuel. The ethanol blending ratios were 0% (DE_0) for pure diesel, and 3% (DE_3), 5% (DE_5) and 10% (DE_10) for 3%, 5% and 10% ethanol mixtures (by vol.%). Blending ethanol with diesel fuel increased the maximum combustion pressure by up to 4.1% compared with that of pure diesel fuel, and the maximum heat release rate increased by 13.5%. The brake specific fuel consumption (BSFC) increased, up to 5.9%, as the ethanol blending ratio increased, while the brake thermal efficiency (BTE) for diesel-ethanol blended fuels remained low, and was maintained at 23.8%. The coefficient of variation (COV) of the indicated mean effective pressure (IMEP) was consistently lower than 1% when ethanol was blended. The blending of ethanol increased the ignition delay from a 12.0 degree crank angle (°CA) at DE_0 to 13.7 °CA at DE_10, and the combustion duration was reduced from 21.5 °CA at DE_0 to 20.8 °CA at DE_10. When ethanol blending was applied, nitrogen oxides (NOx) reduced to 93.5% of the level of pure diesel fuel, the soot opacity decreased from 5.3% to 3% at DE_0, and carbon monoxide increased (CO) by 27.4% at DE_10 compared with DE_0. The presence of hydrocarbon (HC) decreased to 50% of the level of pure diesel fuel, but increased with a further increase in the ethanol blending ratio. The mean size of the soot particulates was reduced by 26.7%, from 33.9 nm for pure diesel fuel, DE_0, to 24.8 nm for DE_10. [ABSTRACT FROM AUTHOR]

This experimental investigation deals with running the IC engine with waste plastic oil (WPO) blends in diesel and LHR. The properties of the oil derived from waste plastics were analyzed and it was found that it has properties similar to the diesel, low heat rejection technique is also employed to improve the performance of the engine by coating the piston, cylinder head with PSZ coating at different thickness. Waste Plastic Oil (WPO) blends in diesel with LHR was tested as a fuel in a D.I. diesel engine and its performance characteristics were analyzed and compared with diesel fuel (DF) operation. It is observed that the engine could operate with waste plastic oil blends in diesel with low heat rejection such as used as fuel in diesel engines. Oxides of nitrogen (NOx) were higher by about 20% and carbon monoxide (CO) reduced by waste plastic oil blends in diesel with LHR operation compared to diesel fuel (DF) operation. Hydrocarbon was reduced by 15% and smoke also reduced by 20% at full load for plastic oil blends in diesel with LHR compared to DF. Engine fueled waste Plastic oil blends in diesel with LHR exhibits higher thermal efficiency up to 80% of full load and exhaust gas temperature was higher at all loads compared to DF and WPO blends with LHR operation. [ABSTRACT FROM AUTHOR]

This research focused on utilizing the waste plastic oil (WPO) effectively in a light-duty direct injection (DI) diesel engine that is predominantly used in the Indian agricultural sector. This approach is critical from the environmental perspective as it provides a solution to two major issues: (1) waste plastic management, which is a challenge for municipalities across the world and (2) reduction of diesel dependency using fuel derived from waste plastic as an alternative fuel for diesel engines. For this purpose, WPO was extracted from mixed waste plastic via catalytic pyrolysis in a lab-scale extraction unit. Later, the effects of oxygenated, renewable n-hexanol addition with baseline diesel and WPO were investigated. Three ternary blends were prepared by splash blending n-hexanol with WPO and diesel: (1) D50-W40-H10, (2) D50-W30-H20, and (3) D50-W20-H30. The performance and tailpipe emission characteristics of DI diesel engine when fueled with these ternary blends were then analyzed in comparison with both neat WPO and diesel operation. Results indicated that D50-W20-H30 presented lower NOx and smoke emissions with 1.5 and 22.8% against diesel and 7.22 and 76.88% against neat WPO, respectively. Brake thermal efficiency (BTE) was found to deteriorate with increasing n-hexanol fraction to the blend. D50-W20-H30 presented the lowest BTE among the blends, but it showed 7.6% increased BTE when compared to WPO and suffered 6% loss in performance against diesel. Reformulation of WPO with n-hexanol derived from lignocellulosic biomass feedstock presents an attractive opportunity to utilize both a recycled and a renewable fuel in diesel engines. [ABSTRACT FROM AUTHOR]

Ever-tightening particulate emissions regulation and the need of extending diesel particulate filter (DPF) manual cleaning period require an in-depth investigation into exhaust-borne ash components that may potentially deposit in DPF using a variety of methods to accelerate loading. Currently, the most common method used is blending a certain volume of lubricant oil into diesel. Predictably, the addition of lubricant oil will alter the nature of particles emitted from engines, creating an artifact between "accelerated" and real ash and therefore biasing the functionality of this method. However, such impacts haven't been carefully evaluated. In this paper, the mass, number, size-resolved distribution, morphology, and elemental analysis of the particles from a Euro-5 compliant, 2.5 L diesel engine consuming conventional diesel, diesel+2v% lubricant oil, and diesel+4v%lubricant oil were measured and compared 24. The results indicate that with the addition of lubricant oil into diesel, both the particulate mass and number emission increased dramatically, a proportional increase in particle numbers of all size stages was seen with 2% lubricant oil blending, while 4% blending only increased the number concentrations of nuclei-mode and relatively large particles. Adding lubricant oil into diesel tended to complicate the microstructure of particles. Particle-bound phosphorus and zinc were only identified when lubricant oil was dosed. An increased oxygen mass fraction with the presence of lubricant oil also suggests heavier volatile materials emissions. Lastly, although burning diesel/lubricant oil mixtures enables an accelerated ash loading process in a DPF, excessive blending ratio could alter the nature of engine-out particles and increase uncertainty. It is recommended to achieve fast ash accumulation at a high engine load with diesel+2v%lubricant oil. • The impacts of adding lubricant oil into diesel on particle nature were studied. • PM, PN and, particle-bound O, S, P, Ca, Mg, Zn all increased with oil addition. • Particles became smaller but more aggregated once lubricant oil was added. • 2% oil addition is recommended for ash loading acceleration. [ABSTRACT FROM AUTHOR]

In this study, engine operating conditions which given the best result in terms of performance, exhaust emission and combustion characteristics in a thermal barrier coated (TBC) diesel engine, which was covered with ceramic on combustion chamber elements, were determined by multi-criteria decision-making (MCDM) method. It was also included in the optimization of the data obtained from the uncoated (standard) engine (STD) in order to better evaluate the TBC engine. In the experimental study, diesel, pure biodiesel derived from cotton oil frying waste and biodiesel/diesel blend fuels (5, 20 and 50% by volume) were used as fuel. In optimization, operational competitiveness rating (OCRA) was preferred as a MCDM. The experimental data, which included a total of six hundred data, in TBC and STD engines fueled biodiesel and its blends were used in optimization. According to the optimization result, the best results in terms of engine performance, exhaust emission and combustion characteristics were generally obtained from the TBC engine. According to the optimization sequence, the ranking obtained from the TBC engine were observed to be ahead of the STD engine at all engine speeds. It was also found that the best results were concentrated at engine speeds of 1800 rpm and 2100 rpm. The best result was achieved by using B20 (20% biodiesel + 80% diesel) in TBC engine at 1800 rpm. The performance, emission and combustion characteristics obtained under these optimum operating parameters (OOP) were also compared with those of the STD engine fueled with B0 and B100. • The forehead surfaces of pistons and valves were covered with ceramic. • Biodiesel and its mixtures were used as fuel in the engine. • The tests were applied at varied engine speeds and full load. • The optimum operating conditions were determined by OCRA method. [ABSTRACT FROM AUTHOR]

The main purpose of the study is to characterise the effects of diesel, biodiesel blends B5M10 and B10M10 and emulsion fuels B5M10E3 and B10M10E3 as fuels for the impact on particulate matter emission. Engine tests have been performed to obtain results of engine performance, gas emission and particulate matter with various cycles. Excel analysis methods were used to analyse the data obtained. The B5M10E3 produces lower ...... emission results than B10M10E3 as biodiesel fuel increases the combustion temperature. In conclusion, biodiesel blends able to reduce emissions of particulate matter and gas emissions compared to diesel but increase ...... emissions. Therefore, emulsion fuels B5M10E3 and B10M10E3 can be the best alternative fuel for the future. [ABSTRACT FROM AUTHOR]

This research investigates the behavior of ethanol and biodiesel, blended with diesel fuel in a multiple injection engine. Numerical study and engine simulation were carried out using ESE Diesel environment of AVL Fire. The simulations were conducted for 10 and 20% biofuel blends and also, 20 and 30% pilot injection and for two different injection timings. Heat release rate and pressure were compared to the studies in the literature. Agreement between pressure charts was very good while it was acceptable for the heat release rate. For the first case, the injection started at 695 CA while for the second one, it started at 700 CA. The duration of injection for both injection stages lasted 10 CA degree with a dwell angle of 15 CA. According to the results, unlike biodiesel combustion, ethanol combustion resulted in lower chamber temperature and lower NOx emission subsequently. The effect of pilot injection percentage on emissions and heat release rate significantly depends on the injection timing. And finally, as injection start changed from 695 to 700, a noticeable reduction was observed in engine performance and emissions. • Ethanol blends result in lower NOx and soot emission due to lower combustion Temp. • As bio-ethanol blend percentage increases, NOx emission decreases. • Injection timing is the most important parameter influencing engine parameters. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of castor biodiesel and its blends on the emission characteristics of a compression ignition engine. The research work was carried out on a single cylinder, four-stroke, water cooled, direct injection diesel engine by using biodiesel made from castor oil, compared with conventional diesel. The fuels used in the analyses are B5, B10, B15, B20, B25, B50, B100 and convectional diesel. The compression ignition engine was operated by varying the loading conditions (0 - 6 kW) in a step of 1 kW. Based on the parameters measured, detailed analyses were carried out on five regulated exhaust emissions i.e. NOX, CO, CO2, O2, and HC. The results clearly indicated that the engine running with biodiesel and their blends were reduced in CO, CO2 and HC emission by up to 20%. However, further reductions in emissions (CO, CO2, and HC) were observed as biodiesel concentration increases in the blends. Also, for biodiesel and its blends, the NOX (10.6% - 37.7%) emissions increased with increase in the load and, directly proportional to biodiesel concentration while O2 reduces as the load increases and increases as biodiesel concentration increased. The results from the experiments suggested castor biodiesel oil with the engine exhaust gases could be a good substitute fuel for existing diesel engine. [ABSTRACT FROM AUTHOR]

The research aimed at analysing the influence of the diesel oil temperature on the NOx emission level. The tests were carried out on a test stand equipped with a 9.5 kW multi-fuel compression-ignition engine. The setup constitutes an experimental cogeneration unit discharging the produced energy into the power grid. The measurements were carried out under the D1 test procedure provided by ISO 8178-4 for testing engines operating at a constant speed. As a result of statistical analysis of the results obtained, significant differences were found in the u specific values of the nitrogen oxides emission gained for particular phases of D1 tests, when the engine was fed with diesel fuel of different temperatures. The results obtained confirmed the possibility of limiting the specific emission of NOx only when the engine is running at 75% of its nominal torque. An increase in the NOx emissions was recorded for the remaining loads. [ABSTRACT FROM AUTHOR]

Four kinds of tested fuels were prepared by adding Fe fuel-borne catalyst (Fe-FBC) to diesel at mass concentrations of 0, 100, 200 and 300 mg/kg, named as Diesel, Fe100, Fe200 and Fe300, respectively. Effects of discharge voltage on particle charge characteristic of diesel exhaust were carried out on a bipolar charge agglomeration test bench. Engine exhaust particle sizer and Zeta potential analyser were used to study the particle number concentration and surface electrical charge. The results show that the particle diameter of the peak number concentration becomes smaller with the increase of Fe-FBC content. Based on electrical charge agglomeration, particle coagulation efficiency increases with the increase of discharge voltage and Fe-FBC content, and particle number concentration of Fe300 has the greatest reduction. Besides, both Zeta potential and particle-surface charge increase with the increment of discharge voltage, and particles of Fe300 have the best charging performance among all tested fuels. [ABSTRACT FROM AUTHOR]

This article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in pmax. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the pmax. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NOx level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level. [ABSTRACT FROM AUTHOR]

Ever growing population and increased vehicles have resulted in higher atmospheric concentration of the greenhouse gases, such as carbon dioxide and methane, thus increasing our planet's average temperature leading to irreversible climate changes, which has led to increasingly demanding and stricter legislations on pollutant emission and CO2, as well as fuel economy targets for the automotive industry. As a result, a great deal of efforts and resources has been spent on the research and development of high efficiency and low emission engines for automotive applications in the attempt to reduce greenhouse gas emissions and levels of nitrogen oxides and soot emissions, which affect the air quality. This research has developed strategies to investigate the combustion characteristics, engine performance and exhaust emission of diesel–gasoline dual-fuel operation in a Ricardo Hydra single-cylinder optical engine running at 1200 r/min, equipped with a high-pressure common rail injection system for diesel fuel delivery, and a port fuel injection system, designed and manufactured by the author, for gasoline fuel delivery, in order to allow for dual-fuel operations. In-cylinder pressure measurement is used for calculating all engine parameters, heat release rate and efficiency. In addition to the thermodynamic analysis of the combustion parameters, high-speed imaging of spray and combustion chemiluminescence was used for the optical analysis of the effect of the above-mentioned parameters on auto-ignition and combustion processes. Effects of different substitution ratios and diesel injection strategies at low engine loads were studied when the total fuel energy was kept constant. The three main substitution ratios used in this study include 45%, 60% and 75%, which also indicates the amount of fuel energy from port-injected gasoline, where the rest is provided by the direct injection of diesel. Depending on the testing conditions, such as injection strategy and intake conditions, some dual-fuel operations were able to deliver high efficiency and improved emissions compared to that of a pure diesel engine operation, with the diesel–gasoline operation offering more consistency in improved thermal efficiency. The optical analysis of the combustion illustrates the main difference in the flame propagation, distribution and quality for each substitution percentage, as well as the condition under examination. It was observed that combustions with higher concentration of diesel fuel having more diffusion-like combustion, especially with diesel injection timings closer to the top dead centre, where there is less time for the two fuel and air to properly mix before combustion occurs, resulted in higher temperature and levels of NOx due to the pockets of high diesel concentrations within the combustion chamber, whereas higher concentration of gasoline, especially at earlier diesel injection timings, resulted in more homogeneous fuel mixture and thus lower combustion temperatures. In other words, when the gasoline substitution ratio is lower, optimised start of injection is advanced further, so that richer diesel mixture needs longer ignition delay to have proper combustion timing, and combustion is milder and peak heat release rate is slightly lower due to less local diesel rich mixture area by means of earlier injection timing, and in terms of emissions, lower gasoline substitution ratio, decreases NOx with more homogeneous diesel mixture, and same can be said for total hydrocarbon. Performing the thermodynamics testing with an all metal piston alongside the optical testing allowed for the confirmation of these outcomes. This study not only delivers an insight to the benefits of dual-fuel engine operation, it also represents the benefits of optical engines in providing better understanding of engine operation and ways of improving it. [ABSTRACT FROM AUTHOR]

Biodiesel is an alternative sustainable energy source and can be utilized in the compression ignition engine without any changes in the engine design. This research work focuses on the preparation of Calophyllum inophyllum methyl ester through two steps of transesterification process and its implementation in common rail direct injection diesel engines under various fuel injection strategies. At the initial stage of the current research work, two biodiesel blends of 10 vol% and 20 vol% with remaining quantity as diesel have been used as fuel in a diesel engine at a fuel injection pressure of 600 bar at 5%, 10% and 15% pilot injection variations. In the second stage, the study has been extended for the same strategies of injecting the fuel at the rates of 10% and 20% exhaust gas recirculation. All the experimental results are compared with diesel fuel at an injection pressure of 600 bar with 10% pilot injection. The experimental results revealed that an increase in the blend ratio of biodiesel enhances the combustion, performance characteristics and proliferation of pilot injection from 5 to 15% facilitates spontaneous and complete combustion. It is observed that 15% pilot injection quantity of 20 vol% Calophyllum inophyllum methyl ester blend has shown the best performance among the test samples with other injection strategies. The results also showed that the implementation of exhaust gas recirculation at 10% and 20% rates during diesel engine operation is evident in lower performance characteristics with a significant impact on oxides of nitrogen and carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

This study was compiled from the results of various researches performed on using diethyl ether as a fuel or fuel additive in diesel engines. Three different techniques are used, the reduction of the harmful exhaust emissions of diesel engines. The first technique for the reduction of harmful emissions has improved the combustion by modification of engine design and fuel injection system, but this process is expensive and time-consuming. The second technique is the use of various exhaust gas devices like catalytic converter and diesel particulate filter. However, the use of these devices affects negatively diesel engine performance. The final technique to reduce emissions and also improve diesel engine performance is the use of various alternative fuels or fuel additives. The major pollutants of diesel engines are nitrogen oxides and particulate matter. It is very difficult to reduce nitrogen oxides and particulate matter emissions simultaneously in practice. Most researches declare that the best way to reduce these emissions is the use of various alternative fuels i.e. natural gas, biogas, biodiesel, or the use of fuel additives with these alternative fuels or conventional diesel fuel. Therefore, it is very important that the results of various studies on alternative fuels or fuel additives are evaluated together for practice applications. Especially, this study focuses on the use of diethyl ether in diesel engines as fuel or fuel additive in various diesel engine fuels. This review study investigates the effects of diethyl ether on the fuel properties, injection, and combustion characteristics. [ABSTRACT FROM AUTHOR]

The present investigation highlights the effect of variable compression ratio (VCR) on the performance and exhaust emission characteristics of a single cylinder, direct injection diesel engine fueled with undi‐diesel blends. 10%, 20%, 30%, 40%, and 50% undi fuel have been added to diesel in volumetric proportions and tested by varying compression ratio (CR) from 16:1 to 20:1. Undi addition to diesel fuel significantly improves the brake thermal efficiency (BTE) and brake specific energy consumption (BSEC) of the engine. In addition, higher CR facilitates to improve unburned hydrocarbon (UHC), carbon monoxide (CO) and smoke opacity of the diesel engine with the penalties of higher oxides of nitrogen (NOX) emissions. In perspective of the engine experimental outputs, a Taguchi assisted Fuzzy based trade off study has been conducted to screen and locate the optimal diesel engine operating conditions, namely, CR, undi share, and load. The optimum process parameter has been found to be A2B6C2 with a multi performance characteristics index (MPCI) value of 0.683 indicating the optimum operating conditions of 17:1 CR, 50% (by volume) undi share at 50% load. [ABSTRACT FROM AUTHOR]

The study to improve the characteristics in terms of performance, emission and combustion aspects without any modification to a direct injection compression ignition engine using pine oil blend and additive addition was executed. Biofuels known for their reduction in emission also degrades the engine's performance value. To overcome this, pine oil mixture was used with an additive (1,4-dioxane). Pine oil taken at two different concentrations (P20, P40) and the additive at two varying proportions (5 ml, 10 ml) were utilized. In total, six pine oil mixtures were prepared and analyzed for the emission, performance and combustion aspects of the test engine and compared with diesel values. The result evidenced the rise of 3.88% and 5.57% for brake thermal efficiency and fuel consumption, respectively, for P20-10 ml blend compared with diesel. Contemplating the emission aspects, considerable decrease in pollutants (22.41% CO, 29.19% HC and 22.80% smoke) excluding NOx and CO2 at peak load conditions was depicted. NOx and CO2 increase about 7.23% and 25.41%, respectively. Combustion parameters like heat release rate and peak pressure of pine oil mixture exhibited inferior values compared with diesel. Only P20 blend with 10 ml additive exhibited values very close (a drop of 2.8% HRR and 2.4% CP) to that of diesel value. To conclude, out of half-dozen blends when compared with diesel, P20 with 10 ml additive proves as the best blend, providing much capable outcomes. [ABSTRACT FROM AUTHOR]

Users of fossil fuels are facing a range of challenges such as long-term rising demand, climate concerns due to emission of greenhouse gases, ecological pollution, finite reserves and price uctuations. Diesel fuel is similarly affected, though with its own subset of issues. Studies suggest that diesel fuel character- istics are affected by addition of nanoparticles. In this research, carbon nanotubes (CNTs) were blended with pure diesel as an additive at concentrations of 30, 60, and 90 ppm to assess the emission and performance characteristics of a single-cylinder compression combustion engine. The considered emission con- tents included CO, CO2, HC, and NO produced by an engine at 50% and 100% loads, at 1800, 2300, and 2800 rpm. Addi- tion of CNTs to the diesel fuel considerably reduced the emis- sion of CO, CO2, HC, and NO compared to additive-free diesel fuel. Furthermore, with the addition of carbon nanotubes, the Exhaust Gas Temperature (EGT) and the Brake Specific Fuel Consumption (BSFC) decreased, while the power and Brake Thermal Efficiency (BTE) increased at all loads and speeds of the engine. [ABSTRACT FROM AUTHOR]

Biomass acquires better ability to replace crude petroleum products in most of all the forms. Cardanol oil extracted from cashew nut shell liquid by pyrolysis process represents a growing abundant energy source. In this work, cardanol oil was extracted by pyrolysis process and chemical composition was studied by using gas chromatography–mass spectroscopy. Experimental investigations were conducted in a single cylinder direct injection diesel engine with different blends of cardanol oil–diesel fuel such as neat diesel, B20, B40, B60, B80, and B100. From the pragmatic results, it was observed that at full load operating condition and at B40, without any modifications in engine, brake thermal efficiency was increased by 1.82% and specific fuel consumption was reduced by 1.8%. On the other hand, carbon monoxide emission was same as that of diesel for all the blends at maximum load conditions. Unburned hydrocarbon for B40 was lower than all blends and was slightly higher than diesel fuel at full load. Formation of nitrogen oxide was slightly higher than diesel fuel for all blends in proportion with increase in load. Smoke opacity gradually reduces with increase in load for all blends and B40 shows much reduced level than diesel at full load. Overall, B40 shows better performance and much comparable emission level with diesel fuel. [ABSTRACT FROM AUTHOR]

In this paper, the numerical simulation of the diesel and gasoline fuels injection in a constant volume chamber and in a cylinder under the operating conditions of a compression ignition (CI) engine is conducted. The simulation results are compared with the experimental data which derived from fast imaging techniques. In order to check out the possibility of using gasoline instead of diesel to increase the volumetric efficiency of the CI engine, the spray characteristics of the gasoline and diesel with injection pressures of 40 and 80 MPa, as well as temperatures of 243, 273 and 313 K, under cold start condition is investigated. The results show that under the same conditions, the vapor penetration length for the two fuels is approximately equal and due to the lower volatility of the diesel fuel, its liquid penetration length in 40 and 80 MPa injection pressures was found to be 7 and 9 mm higher than gasoline, respectively. In addition, the reduction in fuel temperature from 313 K to 243 K leads an increase in the penetration of gasoline and diesel liquids by 12 and 10 mm, respectively. Finally, the decrease in the evaporation rate causes a non-homogeneous mixture and results an increase in the unburned hydrocarbons and emissions. [ABSTRACT FROM AUTHOR]

Stable neat oil emulsions were prepared and tested in a multi-cylinder engine to assess the exhaust emission and performance characteristics. The heating value of the biofuel-diesel blend emulsion was 16.8% higher than neat rapeseed oil and 6.7% lower than neat diesel fuels. The density of the biofuel emulsions were increased by up to 11% as compared to neat fossil diesel. The engine produced similar power output when emulsified fuels were used instead of fossil diesel. At full load, the thermal efficiency of neat biofuel emulsion was 12% higher than that of fossil diesel. At higher loads, the bsfc of the biofuel blend emulsion was very close to that of fossil diesel. Compared to fossil diesel, emulsified fuels gave slightly higher CO 2 emissions. Biofuel and biofuel-diesel blend emulsions produced up to 15% lower NOx emissions. At 100% load, the smoke intensity of biofuel blend emulsion was about 29% lower than neat fossil diesel operation. Emulsified fuels combusted well, and at higher loads produced similar exhaust gas temperatures to those in neat fossil diesel operation. The study concluded that neat oil - diesel - water emulsion fuel could be used in an unmodified diesel engine for increased thermal efficiency and decreased emissions. • Stable single phase biofuel-diesel blend emulsions were prepared. • Thermal efficiency of the emulsion was increased by up to 12% than for diesel. • At high loads, bsfc of the biofuel blend emulsion was very close to that of diesel. • Biofuel emulsion operation gave up to 15% NOx gas reduction than diesel. • Smoke intensity of the emulsion was about 29% lower than diesel operation. [ABSTRACT FROM AUTHOR]

This study investigates the emission behavior of diesel fuel by adding TiO2 nanoparticles in four-stroke, single-cylinder, compression-ignition (CI) engine. This work is aimed at reducing the harmful tailpipe emissions from compression ignition engine when fueled with neat diesel. 50 and 100 ppm of TiO2 nano additive were mixed with diesel using ultrasonicator. Addition of TiO2 nano additive was aimed to enhance the burning properties of diesel and lower its tailpipe emissions. Experimental work concluded that the test fuels used in this study does not require any modification in engines. In addition, the combustion of fuels was smooth and there was no physical and visible damage in the engine components when fueled with base and modified fuels. It was found that by adding 50 and 100 PPM of TiO2 nanoparticles to diesel, significant reduction in CO, HC, NOx, and Smoke emissions were observed. [ABSTRACT FROM AUTHOR]

The article considers the problem of the negative impact of the exhaust gases of diesel internal combustion engines on the environment and human health. The types of organization of the ignition process and the process of fuel combustion in a diesel engine are considered. The reasons for the occurrence of increased particulate matter in internal combustion engines in exhaust gases are also described. The main factors affecting the delay of ignition are given. The main stages of soot formation in diesel internal combustion engines are described. The influence of temperature distribution in the jets of injected fuel and the dependence of emissions on the coefficient of excess air are considered. As a result, the main conclusions are given on ensuring the reduction of solid particles in the exhaust gases of diesel engines by optimizing the combustion process. [ABSTRACT FROM AUTHOR]

The idea of using water-in-Diesel (W/D) emulsion in recent studies as fuel for diesel engines is to reduce the emissions. The introduction of water into a diesel engine using W/D emulsion has a number of potential benefits and can be used as an alternative fuel. One of important factors to use this fuel was the distribution of water droplets in emulsion and emulsifier stability. In the present work, the effect of emulsifier dosage (water in diesel ratio) and heating of W/D emulsion on the stability period with using optical technique was investigated. Five samples of W/D emulsion at different emulsifier dosages (5%, 10%, 15%, 20%, and 25%) water content were studied, whereas the heating of emulsions was carried out for 40oC, 60oC, and 80oC. The results obtained from the current work manifested that an increase in water dosage to W/D emulsion had bad effects on the stability period, also, the increase in heating temperature for W/D emulsion revealed a negative effect on the emulsion stability. [ABSTRACT FROM AUTHOR]

Usage of oxygenated fuels either as replacement to fossil fuels or as additives to fossil fuels and alternative fuels is given much interest. Diethyl Carbonate (DEC) is an oxygenated additive which is non-toxic in nature and biodegradable as well. The objective of this study is to replace utilization of diesel fuel on diesel engine by 50 vol% with Waste Plastic Oil (WPO). This study also analyses the effect of addition of DEC in proportions of 5, 10 and 15 vol% to WPO on performance and emission of a diesel engine. Test fuels D50WPO50 (50% diesel + 50% WPO), D50WPO45DEC5 (50% diesel + 45% WPO + 5% DEC), D50WPO40DEC10 (50% diesel + 40% WPO + 10% DEC) and D50WPO35DEC15 (50% diesel + 35% WPO + 15% DEC) were prepared. Tests were conducted on a single cylinder diesel engine at 20%, 40%, 60%, 80% and 100% load. The results of performance and emission characteristics of test fuels were compared with diesel fuel. Test results show that the spray effect of DEC has increased brake thermal efficiency and reduced brake specific fuel consumption. Addition of DEC to WPO-diesel blends not only optimize the burning process but also minimize engine exhaust emissions. The problems of fuel energy crisis and plastic waste management can be addressed simultaneously with production and utilization of fuel produced from plastic wastes. [ABSTRACT FROM AUTHOR]