Sam Ki Yoon

With the stricter emission regulations for internal combustion engines, electric vehicles, including electrically powered port tractors, have received increasing attention. However, currently, most of the filters used in electric vehicles are conventional membranes that only have the function of filtering particles and foreign objects. Therefore, in order to improve the above issues, the surface of commercial non-woven filter membranes was coated with Ag nanopowder nanofibers and AgNO₃ nanofibers via electrospinning. At present, the comparative research on the antibacterial ability of Ag nanopowder and AgNO₃ is still blank in the same research system, especially with the use of electrospun coating technology. The morphologies and structures of non-woven fabrics and electrospinning coated samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The characterization results indicate that both pure PVA and PVA composite fibers can be successfully coated on the surface of non-woven fabrics. The average diameter of all electrospun PVA composite fibers is distributed in the range of 470–700 nm. The PVA nanofibers with a low content of 1 wt% AgNO₃ have good antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with clearance clear zones of inhibition of 26.00 mm and 17.30 mm, respectively.

In this study, pure diesel fuel (E0), 5% bioethanol blended with 95% diesel fuel (E5), 10% bioethanol blended with 90% diesel fuel (E10) and 15% bioethanol blended with 85% diesel fuel (E15) were tested on a diesel engine. The 40, 60 and 80 Nm were the main experimental variables, while the engine speed was kept constant at 1500 rpm. The main results show that the addition of ethanol slightly reduced the maximum combustion pressure and delayed the combustion start, but increased the heat release rate (HRR) to varying degrees. Although the addition of ethanol was not very helpful for reducing hydrocarbon (HC), it could reduce carbon monoxide (CO) under appropriate load conditions (60 Nm and 80 Nm). Additionally, nitrogen oxides (NOx) and smoke emissions were reduced with the addition of ethanol under all test conditions.

The aim of this work is to investigate the effects of different diesel–bioethanol blended fuels on combustion, engine performance, and emission characteristics in a four-cylinder common rail direct injection (CRDI) diesel engine according to various engine loads. Combustion characteristics including in-cylinder pressure, maximum in-cylinder pressure, heat release rate (HRR), and maximum HRR; engine performance including brake specific fuel consumption (BSFC); and emission characteristics including carbon monoxide (CO), hydrocarbon (HC), nitrogen oxides (NOx), and smoke were compared and analyzed. The four test fuels were diesel (D100), 95% D100 blended with 5% ethanol by volume (D95E5), 90% D100 blended with 10% ethanol by volume (D90E10), and 85% D100 blended with 15% ethanol by volume (D85E15). The results indicated that the addition of ethanol had no great impact on the in-cylinder pressure and HRR, but it could significantly reduce CO, NOx, and smoke emissions. The only deficiency was that BSFC was increased to varying degrees with increase of ethanol due to its low heating value.

At present, the preparation cost of biodiesel is still higher than that of diesel. Thus, directly using vegetable oil before transesterification can greatly reduce the cost. This study investigated the application characteristics of the direct use of crude palm oil (CPO) in a common rail direct injection (CRDI) diesel engine. In this study, the combustion characteristics, engine performance, and emission characteristics of the CRDI diesel engine operated with CPO0 (neat diesel fuel), CPO10 (10% CPO blended with 90% diesel fuel by volume), CPO30 (30% CPO blended with 70% diesel fuel by volume), and CPO50 (50% CPO blended with 50% diesel fuel by volume) at three idling speeds (750 rpm, 1500 rpm, and 2250 rpm) were evaluated. The results obtained from the experiment elucidate that combustion starts earlier by increasing the idling speed. The addition of CPO to diesel fuel resulted in a decrease in the peak in-cylinder pressure at all idle speeds and a decrease in the maximum heat release rate (HRRmax) at 750 and 1500 rpm, but an increase in HRRmax at 2250 rpm. On the other hand, increasing idle speed is beneficial for reducing carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx), but it increases smoke emissions. In addition, adding 10% and 30% CPO to diesel fuel can reduce both HC, NOx, and smoke emissions simultaneously.

Vegetable oil as an alternative fuel for diesel engine has attracted much attention all over the world, and it is also expected to achieve the goal of global carbon neutrality in the future. Although the product after transesterification, biodiesel, can greatly reduce the viscosity compared with vegetable oil, the high production cost is one of the reasons for restricting its extensive development. In addition, based on the current research on biodiesel in diesel engines, it has been almost thoroughly investigated. Therefore, in this study, crude palm oil (CPO) was directly used as an alternative fuel to be blended with commercial diesel. The combustion, engine performance and emissions were investigated on a 4-cylinder, turbocharged, common rail direct injection (CRDI) diesel engine fueled with different diesel-CPO blends according to various engine loads. The results show that adding CPO to diesel reduces the maximum in-cylinder pressure and maximum heat release rate to 30 Nm and 60 Nm. The most noteworthy finding is that the blend fuels reduce the emissions of hydrocarbons (HC), nitrogen oxides (NOx) and smoke, simultaneously. On the whole, diesel fuel blended with 30% CPO by volume is the best mixing ratio based on engine performance and emission characteristics.

As an environmentally friendly water-soluble polymer, polyvinyl alcohol (PVA) has attracted extensive attention because of its non-toxic, degradable, low cost, and good biocompatibility. Electrospinning is a kind of nanotechnology, and the nanofiber membrane prepared by it has the advantages of large surface area-to-volume ratios, nano- to micron-sized fibers, etc. Herein, a simple and facile one-step green electrospinning method was developed to fabricate various environmentally friendly PVA nanofiber membranes. The lipophilic properties of PVA membranes were investigated and optimized according different PVA concentrations. The PVA electrospun fiber prepared from the solution at a concentration of 10 wt% had the highest adsorption capacity for the adsorption of new and waste engine oils, and the waste engine oil adsorption capacity (12.70 g/g) was higher than that of new engine oil (11.67 g/g). It also has a relatively large BET surface area (12.05 m²/g), a pore volume (0.04 cm³/g), and an appropriate pore diameter (13.69 nm) and fiber diameter (174.21 nm). All electrospun PVA membranes showed excellent lipophilic properties due to their oil contact angles of much less than 30°. Therefore, PVA electrospun fibrous membranes have great application potential in the field of purifying engine oil due to the excellent lipophilic properties and oil absorption capacity.

This experiment investigates the combustion and emissions characteristics of a common rail direct injection (CRDI) diesel engine using various blends of pure diesel fuel and palm biodiesel. Fuel injection pressures of 45 and 65 MPa were investigated under engine loads of 50 and 100 Nm. The fuels studied herein were pure diesel fuel 100 vol.% with 0 vol.% of palm biodiesel (PBD0), pure diesel fuel 80 vol.% blended with 20 vol.% of palm biodiesel (PBD20), and pure diesel fuel 50 vol.% blended with 50 vol.% of palm biodiesel (PBD50). As the fuel injection pressure increased from 45 to 65 MPa under all engine loads, the combustion pressure and heat release rate also increased. The indicated mean effective pressure (IMEP) increased with an increase of the fuel injection pressure. In addition, for 50 Nm of the engine load, an increase to the fuel injection pressure resulted in a reduction of the brake specific fuel consumption (BSFC) by an average of 2.43%. In comparison, for an engine load of 100 Nm, an increase in the fuel injection pressure decreased BSFC by an average of 0.8%. Hydrocarbon (HC) and particulate matter (PM) decreased as fuel pressure increased, independent of the engine load. Increasing fuel injection pressure for 50 Nm engine load using PBD0, PBD20 and PBD50 decreased carbon monoxide (CO) emissions. When the fuel injection pressure was increased from 45 MPa to 65 MPa, oxides of nitrogen (NOx) emissions were increased for both engine loads. For a given fuel injection pressure, NOx emissions increased slightly as the biodiesel content in the fuel blend increased.

Air pollutants such as volatile organic compounds (VOCs), nitrogen oxides (NOx), and sulfur dioxide (SO₂), as well as water pollutants (e.g., heavy metals phosphorous, fluoride, boron, phenolic compounds, and dyes), are harmful to humans and the environment. Effective control and reduction of their pollution is therefore an important topic for today’s scientists. Fly ash (FA) is a type of industrial waste that can cause multiple environmental problems if discharged into the air. On the other hand, because of its high porosity, large specific surface area, and other unique characteristics, FA can also be used as a low-cost and high efficient adsorbent for treatment of environment pollutants. This paper reviews the effects of FA on treatment of the air and water pollution, including to the current status of global FA utilization, physicochemical properties, principle of adsorption, and the application direction of FA in the future. Since most researchers only studied the adsorption capacity of pure FA or zeolite (synthesized from FA), the research on the fabrication of nanofiber membranes using FA is still lacking, especially the adsorption of VOCs from air and heavy metals from wastewater using FA nanofiber membranes. Therefore, in this paper, we focus on reviewing and summarizing that FA can be spun into a fiber membrane via electrospinning with the ability to adsorb VOCs and heavy metals from air and wastewater. Moreover, we also evaluate the future application value of FA nanofiber membranes in the field of environmental pollution control. Utilization of nanofiber technology to fabricate multi-functional FA emerging composite materials to mitigate air and water pollution has great potential in the future, especially the use of pollutant materials to control other pollutants.

Due to the rapid development of the global economy, fossil oil is widely used, leading to its depletion and gradual deterioration of the global environment, including global warming, the greenhouse effect, fog, and haze. Therefore, many researchers have been interested in studying alternative fuels in an attempt to develop an eco-friendly fuel to replace traditional fuel and solve the above environmental problems. Biodiesel is a renewable and eco-friendly fuel that is the most promising alternative fuel for diesel engines, and a significant amount of research and development has focused on biodiesel. Canola oil biodiesel (COB) is one type of biodiesel, and it has an advantage in oil production per unit area compared with other biodiesels. This paper summarizes and reviews studies related to the use of COB in different diesel engines under a variety of operating conditions. We focus on evaluating the combustion and emission characteristics of COB based on a large number of papers (including our previous studies). In addition, this paper serves as a valuable reference for in-depth studies of COB use in diesel engines, as it covers the topic from the production of COB to its use in diesel engines.

In this study, the application effects of canola oil biodiesel/diesel blends in a common rail diesel engine was experimentally investigated. The test fuels were denoted as ULSD (ultra low sulfur diesel), BD20 (20% canola oil blended with 80% ULSD by volume), and PCO (pure canola oil), respectively. These three fuels were tested under an engine speed of 1500 rpm with various brake mean effective pressures (BMEPs). The results indicated that PCO can be used well in the diesel engine without engine modification, and that BD20 can be used as a good alternative fuel to reduce the exhaust pollution. In addition, at low engine loads (0.13 MPa and 0.26 MPa), the combustion pressure of PCO is the smallest, compared with BD20 and ULSD, because the lower calorific value of PCO is lower than that of ULSD. However, at high engine loads (0.39 MPa and 0.52 MPa), the rate of heat release (ROHR) of BD20 is the highest because the canola oil biodiesel is an oxygenated fuel that promotes combustion, shortening the ignition delay period. For exhaust emissions, by using canola oil biodiesel, the particulate matter (PM) and carbon monoxide (CO) emissions were considerably reduced with increased BMEP. The nitrogen oxide (NOx) emissions increased only slightly due to the inherent presence of oxygen in biodiesel.