Search Results (96)

Airport operations significantly contribute to air pollution in their vicinity through various sources, including aircraft activities—particularly taxiing and take-off—as well as ground support equipment, service vehicles, and maintenance work. Since emissions from aircraft engines represent the primary pollution source at airports, it is essential to reduce emissions at every phase of the LTO (landing and take-off) cycle to improve local air quality and promote environmental sustainability. Given the research gap in emission analysis, a comprehensive LCA framework for airport pushback and taxi operations is proposed, integrating tow truck propulsion, a taxiing strategy, and fleet management. Given the complexity of the issue, the authors first decided to investigate emissions from taxiing operations using tow trucks with different powertrains. The analyses performed were considered preliminary and a starting point for exploring emissions during taxiing operations at airports. Typically, aircraft are pushed back from the apron and then taxi under their own power using both engines at approximately 7% of maximum thrust. To substantially reduce exhaust emissions, external towing vehicles can be employed to move aircrafts from the apron to the runway. This study evaluates the potential for emission reductions in CO₂ and other harmful compounds such as CO, HC, NO_x, and PM by using electric towing vehicles (ETVs). It also compares emissions from different taxiing methods: full-engine taxiing, single-engine taxiing, ETV-assisted taxiing, and taxiing using diesel and petrol-powered tow vehicles. The analysis was conducted for Warsaw and Poznań airports. Three aircraft types—the most commonly operating at these airports—were selected to assess emissions under various taxiing scenarios. The results show that using electric towing vehicles can reduce CO and NO_x emissions to nearly zero compared to other methods. Interestingly, CO emissions from full-engine taxiing were lower than those from petrol-powered towing, although the Embraer 195 showed the highest CO emissions among the selected aircrafts. HC emissions were lowest for the A321neo and also relatively low for the diesel towing vehicle. The use of electric tow trucks significantly reduces CO₂ emissions: only 2.8–4.4 kg compared to 380–450 kg when taxiing with engines. This research highlights the critical role of sustainable ground operations in reducing harmful emissions and underscores the importance of integrating sustainability into airport taxiing practices. Full article

It is evident that a novel engineering solution is required in order to elevate a greater number of polluting cars into a higher category. There appears to be a paucity of direct interest in upgrading Euro 1, 2, 3, 4, and 5 vehicles to the highest possible level, primarily through software modifications of the parameters determining the performance of the internal combustion engine (ICE). The potential for advancement in this area is evidenced by the presence of systems that enhance environmental efficiency, even in Euro 2 vehicles. These include exhaust gas recirculation, catalytic converter, lambda sensor, electronic control fuel injection, and ignition timing. It is precisely these vehicles that are subject to optimization, a process which would allow the maximum service life of otherwise more reliable but older vehicles to be exploited. Full article

The aim of this study was to determine the influence of initial chain tension, feed force, and wood hardness on the variability of the cutter’s deflection angle during petrol chainsaw operation. Cutting wood with a chainsaw is a complex process that has not been fully elucidated to date. During operation, the position of cutters with respect to the workpiece may vary. The situation is additionally complicated by the fact that chainsaws are powered by one-cylinder gasoline engines characterized by highly variable instantaneous rotational speeds. The experiments involved two types of wood (pine and oak), two initial tension values (tight vs. slack chain), and two feed forces (20 N and 80 N). The cutting process was recorded with a high-speed camera at 12,000 fps to determine cutter deflection angles, instantaneous speeds, and accelerations for all the aforementioned cases. It was found that at the lower feed force the cutter deflection differed depending on the initial chain tension, and a greater cutter deflection angle was observed in pine wood processing. It was also found that speed and acceleration in the Y axis were much lower than in the X axis. Additionally, the rear part of the cutter revealed greater speed variation in the X axis. Full article

This study presents an innovative, eco-friendly approach for converting waste zeolite dust into efficient petroleum sorbents through an integrated agglomeration–deagglomeration process using high-pressure grinding rolls (HPGRs). This method generates secondary porosity without calcination, enhancing sorption while reducing greenhouse gas emissions and supporting sustainable development by valorizing industrial by-products for environmental remediation. The study aimed to assess the influence of binder and water content on petroleum sorption performance, textural properties, and mechanical strength of the produced sorbents, and to identify correlations between these parameters. Sorbents were characterized using mercury porosimetry (MIP), sorption measurements, mechanical resistance tests, scanning electron microscopy (SEM), and digital microscopy. Produced zeolite sorbents (0.5–1 mm) exceeded the 50 wt.% sorption threshold required for oil spill cleanup in Poland, outperforming diatomite sorbents by 15–50% for diesel and 40% for used engine oil. The most effective sample, 3/w/22.5, reached capacities of 0.4 g/g for petrol, 0.8 g/g for diesel, and 0.3 g/g for used oil. The sorption mechanism was governed by physical processes, mainly diffusion of nonpolar molecules into meso- and macropores via van der Waals forces. Sorbents with dominant pores (~4.8 µm) showed ~15% higher efficiency than those with smaller pores (~0.035 µm). The sorbents demonstrated amphiphilic behavior, enabling simultaneous uptake of polar (water) and nonpolar (petrochemical) substances. Full article

Biodiesel is a promising alternative fuel that represents a sustainable and environmentally friendly energy source. Due to its complete carbon cycle, it reduces dependence on fossil fuels and lowers greenhouse gas emissions. However, the use of biodiesel in diesel engines is associated with several challenges, including an increase in nitrogen oxide and particulate emissions, incompatibility with cold climates, and lower calorific value. By using nanoparticles as fuel additives, there is a potential to improve the properties of biodiesel and address its shortcomings. In this work, the characteristics of biodiesel derived from waste cooking oil have been enhanced using nanoparticle additives, which result in the usage of a higher percentage of the biodiesel in diesel engines. Nanoparticles of cerium oxide, silicon dioxide, and aluminum oxide have been investigated in different concentrations as biodiesel additives. Two mathematical models are introduced in this work and solved by LINGO optimization software (version 18); the first one seeks to predict the characteristics of biodiesel with nanoparticles in any blend of diesel–biodiesel–nanoparticles, while the second model aims to maximize the biodiesel ratio in a biodiesel–diesel–nanoparticles blend. The application of the combined two models aids in the selection of the optimal nanomaterial that improves the properties of biodiesel and permits an increase in the biodiesel mixing ratio in the fuel. The results show that the best nanoparticle type is cerium oxide at a concentration of 100 ppm, and the optimal mixing ratio of biodiesel blended with CeO₂ nanoparticles is 24.892%. An unmodified diesel engine is operated and evaluated with the optimum blend (24.892% biodiesel + 75.108% petrol diesel + 100 ppm CeO₂ nanoparticles). It is found that significant improvements in engine performance and emissions compared with the conventional diesel are achieved. The reductions in brake-specific fuel consumption (BSFC), smoke opacity, and carbon monoxide emissions are 24%, 52%, and 30%, respectively. Full article

The transition from traditional petrol-based combustion engines to hydrogen-powered systems represents a promising advancement in sustainable and clean energy solutions. This review paper explores the intricacies of converting a conventional internal combustion engine to operate on hydrogen gas. Key topics include the performance limitations of hydrogen engines, the role of water injection in combustion modulation, and the investigation of direct injection and port injection systems. This review also examines challenges associated with lean and rich mixtures, risks of backfire and pre-ignition, and the conversion’s overall impact on engine performance and longevity. Additionally, this paper discusses hydrogen lubrication to prevent mechanical wear and addresses emission-related considerations. Full article

Biofuels are the most essential types of alternative fuels, which currently have significant potential to reduce CO₂ emissions compared to fossil fuels. Methanol is a more efficient fuel than petrol due to its physicochemical properties, such as a higher latent heat of vaporization, research octane number, and heat of combustion of the fuel–air mixture. Also, biomethanol is cheaper than traditional petrol and diesel fuel for agricultural countries. The authors have proposed a new approach to improve the characteristics and efficiency of methanol diesel engines by using biomethanol mixed with hydrogen instead of pure biomethanol. Using a hydrogen–biomethanol mixture in modern engines is an effective method because hydrogen is a carbon-free, low-ignition, highest-flame-rate, high-octane fuel. A small quantity of hydrogen added to biomethanol and its combustion in an engine with a heat exchanger increases the combustion temperature and heat release, increases engine power, and reduces fuel consumption. This article presents experimental results of methanol combustion and a hydrogen-in-methanol mixture if hydrogen was retained due to the utilization of the heat of the exhaust gases. The tests were carried on a single-cylinder experimental engine with an injection of liquid methanol and gaseous hydrogen mixtures. The experiments showed that green hydrogen generated onboard the car due to the utilization of heat significantly reduced fuel costs of engines of vehicles and technological installations. It was established a hydrogen gaseous mixture addition of up to 5% by mass to methanol requires a corresponding change in the coefficient of excess air to λ = 1.25. Also, using an additional hydrogen mixture requires adjustment at the ignition moment in the direction of its decrease by 4–5 degrees of the engine crankshaft. Hydrogen gas mixture addition reduced methanol consumption, reaching a maximum reduction of 24%. The maximum increase in power was 30.5% based on experimental data. The reduction in the specified fuel consumption, obtained after experimental tests of the methanol research engine on the stand, can be implemented on the vehicle engines and technological installations equipped with an onboard heat recovery system. Such a system, due to the utilization of heat and the supply of additional hydrogen, can be implemented for engines that work on any alternative or traditional fuels. Full article

Decarbonising transport is a crucial element of the UK’s strategy to achieve net-zero carbon emissions by 2050, as the transport sector is currently the largest contributor to the UK’s greenhouse gas emissions. Rural communities face distinct challenges in this effort due to their reliance on internal combustion engines (ICEs) across vehicles and machinery essential for daily life, including farming equipment and private transport. While the upcoming ban on new petrol and diesel vehicles paves the way for the adoption of Electric Vehicles (EVs), this solution may not fully address the unique needs of rural areas where infrastructure limitations and specific mobility requirements pose significant barriers. In this context, synthetic fuels, produced using renewable energy sources, offer a potential alternative. These fuels can be used directly in existing internal combustion engines without requiring major modifications and have the added benefit of reducing overall greenhouse gas emissions by capturing CO₂ during production. This entry explores the potential advantages of adopting synthetic fuels, particularly in rural areas, and examines how community-based buying cooperatives could support their wider use through bulk purchasing, cost reduction, and community empowerment. Full article

Thousands of particle number (PN) counters have been introduced to the European market, following the implementation of PN tests during the periodic technical inspection (PTI) of diesel vehicles equipped with particulate filters. Expanding the PN-PTI test to gasoline vehicles may face several challenges due to the different exhaust aerosol characteristics. In this study, two PN-PTI instruments, type-examined for diesel vehicles, measured fifteen petrol passenger cars with different test protocols: low and high idling, with or without additional load, and sharp accelerations. The instruments, one based on diffusion charging and the other on condensation particle counting, demonstrated good linearity compared to the reference instrumentation with R-squared values of 0.93 and 0.92, respectively. However, in a considerable number of tests, they registered higher particle concentrations due to the presence of high concentrations below their theoretical 23 nm cut-off size. The evaluation of the different test protocols showed that gasoline direct injection engine vehicles without particulate filters (GPFs) generally emitted an order of magnitude or higher PN compared to those with GPFs. However, high variations in concentration levels were observed for each vehicle. Port-fuel injection vehicles without GPFs mostly emitted PN concentrations near the lower detection limit of the PN-PTI instruments. Full article

As industrial production increases worldwide, so does the demand for fuels. The transport of fuels from the point of production to the end user poses a risk of environmental pollution, both during transport and during combustion in internal combustion engines. The soil is a part of the environment which is particularly sensitive to contamination by petroleum substances. For this reason, research has been carried out into the possibility of reducing the impact of petrol on the content of heavy metals in the soil using various materials, both mineral (bentonite, calcium oxide) and organic (compost). These played an important role in the in situ remediation of contaminated soils. Petrol contamination increased the content of some heavy metals (Pb, Cd, or Ni), while it decreased the content of other metals (Cr, Zn, Co, and Cu) in the soil. The materials used in this study significantly altered the levels of heavy metals in the soil. The strength of the effect varied and the direction of the effect depended on the element. Bentonite was the most effective, while calcium oxide and especially compost were less effective. The most beneficial (limiting) effect of calcium oxide was shown on the soil content of cadmium, cobalt, and chromium, while the bentonite effects were on the content of chromium. The application of the abovementioned materials seems to be effective in reducing low level soil contamination by petrol. Full article

The expansion of impervious areas in the context of climate change leads to an increase in stormwater runoff. Runoff from roads, petrol stations, and service stations is the most common form of unintentional release of petroleum hydrocarbons (PHs). Rain gardens are an important practice for removing PHs from stormwater runoff, but little data exist on the removal efficiency and behaviour of these substances within the system. The main objective of the study is to investigate the effectiveness of rain gardens in removing pollutants such as diesel fuel (DF) and used engine oil (UEO) in a laboratory setting, as well as to study the behaviours of these pollutants within the system. Eight experimental columns (7.164 dm³) were packed with soil (bulk density 1.48 kg/dm³), river sand (1.6 kg/dm³), and gravel. Plants of the Physocarpus opulifolia Diabolo species were planted in the topsoil to study their resistance to PHs. For 6 months, the columns were watered with model PHs followed by simulated rain events. The concentrations of PHs in the leachate and soil media of the columns were determined by reverse-phase high-performance liquid chromatography (RP-HPLC). The results of HPLC indicated the absence of UEO and DF components in the leachates of all experimental columns, which suggested 100% removal of these substances from stormwater. The chromatography results showed that 95% of the modelled PHs were retained in the surface layer of the soil medium due to the sorption process, which led to a change in hydraulic conductivity over time. Recommendations are proposed to increase the service life of rain gardens designed to filter PHs from stormwater. Full article

The results of diagnostic tests under steady-state speed conditions of an unloaded engine do not fully reflect the emissivity of vehicles adapted to run on natural gas. Therefore, it is reasonable to pay attention to the emissions performance of these vehicles under dynamic conditions. In this regard, the tests were carried out on a chassis dynamometer with the engine fueled by gasoline and natural gas. Due to the area of operation of natural gas vehicles being usually limited to urban areas, the urban phases of the NEDC (New European Driving Cycle) and WLTC (Worldwide harmonized Light-duty vehicles Test Cycle) were adapted. While CO₂ emissions are lower when fueled by natural gas, CH₄ emissions can be high, which is related to momentary changes in the composition of the combustible mixture. Although CH₄ emissions are higher when the engine runs on natural gas, the CO_2eq value is, depending on the driving cycle, about 15–25% lower than when running on petrol. Additionally, studies have shown that in engines adapted to run on CNG (compressed natural gas), it is advisable to consider the use of catalytic converters optimized to run on natural gas, as is the case with vehicles which are factory–adapted to run on CNG. Full article

Although technical improvements to engines and aftertreatment systems have the greatest impact on pollutant emissions, there is also potential for reducing emissions through driver behavior. This potential can be realized in the very short term, while better emission-control technologies only take effect once they have penetrated the market. In addition to a change in driving style, the vehicle owner’s choice of vehicle technology and size class will also have an impact on the future emissions of the vehicle fleet. The effects of different driving styles, the tire choice, the vehicle size class, and propulsion technologies on energy consumption and tailpipe and non-exhaust emissions are analyzed in this paper for different traffic situations and start temperatures for cars with petrol and diesel combustion engines and for battery electric vehicles. The analysis is completed with the corresponding upstream emissions from fuel and electricity production. The analysis is based on a vehicle simulation using the Passenger car and Heavy-duty Emission Model (PHEM), which is based on a large database of vehicles created using measurements of real driving conditions. For the assessment of the driving style, a novel method was developed in an H2020 project, which reproduces a measured trip with a virtual eco-driver. Carbon dioxide equivalent emissions (CO_2eq) increase with increasing vehicle size, but can be reduced by around 20% for conventional vehicles and 17% for battery electric vehicles (BEVs) through an environmentally conscious driving style. On average, BEVs have around 50% lower CO_2eq emissions than conventional vehicles, if the emissions from vehicle production are also taken into account. On an average journey of 35 km, the cold start of modern diesel vehicles accounts for around half of the total NO_x emissions, while the proportion of cold starts for petrol vehicles is around 25%. Tire and brake wear together generate a similar amount of PN23 emissions as the exhaust gases from new cars. Full article

This study investigates the performance of a 4-MIX engine utilizing hydrogen combustion in pure oxygen, water injection, and the application of the early-intake valve closure (EIVC) Miller cycle. Transitioning from a standard petrol–oil mix to hydrogen fuel with pure oxygen combustion aims to reduce emissions. Performance comparisons between baseline and oxyhydrogen engines showed proportional growth in the energy input rate with increasing rotational speed. The oxyhydrogen engine exhibited smoother reductions in brake torque and thermal efficiency as rotational speed increased compared to the baseline, attributed to hydrogen’s higher heating value. Water injection targeted cylinder and exhaust temperature reduction while maintaining a consistent injected mass. The results indicated a threshold of around 2.5 kg/h for the optimal water injection rate, beyond which positive effects on engine performance emerged. Investigation into the EIVC Miller cycle revealed improvements in brake torque, thermal efficiency, and brake specific fuel consumption as early-intake valve closure increased. Overall, the EIVC model exhibited superior energy efficiency, torque output, and thermal efficiency compared to alternative models, effectively addressing emissions and cylinder temperature concerns. Full article

Due to the large quantities of carbon emissions generated by the transportation sector, cleaner automotive technologies are needed aiming at a green energy transition. In this scenario, hydrogen is pointed out as a promising fuel that can be employed as the fuel of either a fuel cell or an internal combustion engine vehicle. Therefore, in this work, we propose the design and modeling of a fuel cell versus an internal combustion engine passenger car for a driving cycle. The simulation was carried out using the quasistatic simulation toolbox tool in Simulink considering the main powertrain components for each vehicle. Furthermore, a brief analysis of the carbon emissions associated with the hydrogen production method is addressed to assess the clean potential of hydrogen-powered vehicles compared to conventional fossil fuel-fueled cars. The resulting analysis has shown that the hydrogen fuel cell vehicle is almost twice as efficient compared to internal combustion engines, resulting in a lower fuel consumption of 1.05 kg-H₂/100 km in the WLTP driving cycle for the fuel cell vehicle, while the combustion vehicle consumed about 1.79 kg-H₂/100 km. Regarding using different hydrogen colors to fuel the vehicle, hydrogen-powered vehicles fueled with blue and grey hydrogen presented higher carbon emissions compared to petrol-powered vehicles reaching up to 2–3 times higher in the case of grey hydrogen. Thus, green hydrogen is needed as fuel to keep carbon emissions lower than conventional petrol-powered vehicles. Full article