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Abstract: Biodiesels are promoted as alternative fuels and their applications in diesel engines have been investigated by many researchers. However, the particle size distribution emitted from heavy-duty diesel engines fueled with palm-biodiesel blended with premium diesel fuel and paraffinic fuel blended with palm-biodiesel has seldom been addressed. Thus, five test fuels were used in this work to study the particle size distribution: D100 (premium diesel fuel), B100 (100% palm-biodiesel), B20 (20vol% palm-biodiesel+80vol% D100), BP9505 (95vol% paraffinic fuel+5vol% palm-biodiesel) and BP8020 (80vol% paraffinic fuel+20vol% palm-biodiesel). A Micro-Orifice Uniform Deposit Impactor (MOUDI) equipped with aluminum filters was used to collect size-resolved samples. Experimental results indicated that palm-biodiesel blends and paraffinic fuel blends could improve combustion efficiency in diesel engines, but pure palm-biodiesel could cause incomplete combustion. Adding palm-biodiesel to diesel fuel would slightly increase particles with diameter <0.31μm but paraffinic fuel blends could decrease particles with diameter <1μm. The mass median diameter of overall particles (MMDo) and σ g,o are 0.439μm and 3.88 for D100; 0.380μm and 3.24 for B20; 0.465μm and 4.22 for B100; 1.40μm and 4.92 for BP9505; 1.46μm and 2.25 for BP8020. There are more particles with low aerodynamic diameters (diameter <0.31μm) in the exhaust of D100, B20 and B100 fuels. On the other hand, a greater fraction of particulate matter of BP9505 and BP8020 existed in coarse particles (diameter: 2.5–10μm). Energy efficiency also increases significantly by 12.3–15.1% with the introduction of paraffinic fuel blends into the engine. Nevertheless, paraffinic fuel blends also reduce the emission of particulate matters by 36.0–38.4%. Carbon monoxide was decreased by 36.8–48.5%. Total hydrocarbon is 39.6–41.7% less than diesel fuel combustion. Nitrogen oxides emission is about 5% lower for paraffinic fuel. These results show that paraffinic fuel can be very competitive and replaced diesel fuels in the future. [Copyright &y& Elsevier]

Abstract Efficient energy usage and energy saving is one of the nowadays necessity for all scientists of IC engine. This is because of the current environmental challenges that have tremendously increased concerning air pollution, particularly pollutant emissions from vehicles. Yet, industries and governments alike have disregarded this phenomenon which has been considerably contributing to climate change. It is against this background that, the research works carried out in this present study is predominantly focusing on improving energy efficiency and reducing emission levels from diesel engines. This can be achieved with the help of atmospheric-plasma system which can offer a noble solution to the above-mentioned challenges due to its potential to improve combustion efficiency which leads to energy efficiency, while reducing emission levels from diesel engines. In this study, the performance and emissions of a diesel generator supplemented with an atmospheric-plasma system was examined. The diesel engine was used to examine the effects of fuel composition, or brake specific fuel consumption, thermal efficiency and pollutant emissions at different plasma system voltages. To this end, we equally examined the effects of atmospheric-plasma system on energy efficiency improvement and emissions reduction from diesel engine as the main purpose of this study. We do so by testing the diesel-fueled engine generator under the atmospheric-plasma system. The tests were carried out at a constant state condition with the engine running at 2200 rpm with torque and power outputs of 10.4 Nm (75% of the max load) and 2.1 kW, separately, for the tested fuels and this was used to increase the output voltage of the plasma system during this study. The plasma system ionized the intake air and improved the formation of free radicals upon combustion. During this study, the output voltage of the plasma was set within the range of 0–7 kV. The experimental results have indicated that formaldehyde, acetaldehyde and acrolein account for more than 75% of total carbonyl compounds emissions. Simultaneously, it was also observed from the results that higher plasma system voltage reduces pollutants emissions levels. Hence, such reduction is predominantly evident for nitrogen oxides, particulate matters and carbon monoxide. However, the marginal improvements of engine performance and emissions reduction become insignificant when the plasma system voltage reaches 6 kV. On the other hand, increasing the amount of plasma system voltages in diesel engine continues to significantly reduce pollutant emissions. Graphical abstract Image 1 Highlights • Atmospheric plasma system saves energy and reducing emission levels. • Formaldehyde, acetaldehyde and acrolein accounts for 75% of carbonyl compounds. • Higher plasma system voltage lowers pollutants emissions levels. • Improve engine performance as plasma system voltage reaches 6 kV. • PM concentration has been reduced considerably by higher plasma voltage. [ABSTRACT FROM AUTHOR]

Abstract: This work investigated the effects of induction of hydrogen and oxygen mixture (H2/O2) to a heavy-duty diesel engine (HDDE) on the thermal performance, fuel consumption and emission characteristics. The HDDE was tested at one low load steady-state condition, 24.5% of the max load (40km/h), using neat diesel and seven H2/O2 mixtures: 10–70L/min, interval 10L/min. The results show that brake thermal efficiency is increased from 31.1% for neat diesel to 39.9% for 70L/min of H2/O2 mixture. For 10–40L/min of H2/O2 mixture addition, the brake specific fuel consumption (BSFC) was higher than that of neat diesel. However, for 50, 60 and 70L/min of H2/O2 mixture addition, the BSFC was lower than that of neat diesel by about 3.2%, 9.9% and 10.5%, respectively. Due to improved combustion efficiency, the emission concentrations of hydrocarbon, carbon dioxide and carbon monoxide were all lowered, while those of the nitrogen oxides were increased. [Copyright &y& Elsevier]

Abstract: Biodiesels have received increasing attention as alternative fuels for diesel engines and generators. This study investigates the emissions of particulate matter (PM), total carbon (TC), e.g., organic/elemental carbons, and polycyclic aromatic hydrocarbons (PAHs) from a diesel generator fuelled with soy-biodiesel blends. Among the tested diesel blends (B0, B10 (10vol% soy-biodiesel), B20, and B50), B20 exhibited the lowest PM emission concentration despite the loads (except the 5kW case), whereas B10 displayed lower PM emission factors when operating at 0 and 10kW than the other fuel blends. The emission concentrations or factors of EC, OC, and TC were the lowest when B10 or B20 was used regardless of the loading. Under all tested loads, the average concentrations of total-PAHs emitted from the generator using the B10 and B20 were lower (by 38% and 28%, respectively) than those using pure petroleum diesel fuel (B0), while the emission factors of total-PAHs decreased with an increasing ratio of biodiesel to premium diesel. With an increasing loading, although the brake specific fuel consumption decreased, the energy efficiency increased despite the bio/petroleum diesel ratio. Therefore, soy-biodiesel is promising for use as an alternative fuel for diesel generators to increase energy efficiency and reduce the PM, carbon, and PAH emissions. [Copyright &y& Elsevier]