Decreased Carbon Monoxide Research Articles

Tailpipe emissions and fuel consumption of a heavy-duty diesel vehicle using palm oil biodiesel blended fuels

Biodiesel application, such as using waste cooking oil biodiesel in Shanghai, China, is a sustainable solution that addresses the challenges posed by escalating air pollution, energy security, and climate change. Future efforts may involve blending biodiesel from alternative sources like crude palm oil with diesel in China. This study tested a China V heavy-duty diesel vehicle equipped with a selective catalytic reduction (SCR) system using various palm oil biodiesel blended fuels (i.e., B0, B5, B10, and B20). The findings indicated that using biodiesel blends led to reductions in carbon monoxide (CO), hydrocarbon (HC), and particle number (PN) emissions compared to B0, while nitrogen oxide (NOX) emissions remained similar. Higher biodiesel content significantly reduced petroleum diesel consumption, but no statistically significant differences were found in total carbon dioxide (CO2) emissions and fuel consumption. Various factors such as vehicle speed, payload, and cold starts influence tailpipe emissions and fuel consumption. Specifically, high-speed phases notably reduced CO, HC, and PN emissions with the use of biodiesel blends. Lower payloads were linked to decreased CO2 emissions and fuel consumption but increased NOX emissions. Cold starts increased HC and NOX emissions, especially with higher biodiesel blending ratios. These results can provide valuable empirical insights into palm oil biodiesel emissions.

Residues from the Oil Pressing Process as a Substrate for the Production of Alternative Biochar Materials

The purpose of this study was to evaluate the feasibility of using residues from cooking oil production to produce alternative biochar fuels along with optimizing the pyrolysis process. The work consisted of carrying out the pyrolysis process at varying temperatures and holding times at the final temperature, and then evaluating the energy potential of the materials studied. Taking into account aspects of environmental emissions, the content of selected oxides in the flue gases generated during the combustion of cakes and the biochar obtained from them was evaluated. Plant biomass derived from a variety of oilseeds, i.e., fennel flower (Nigella sativa L.), rapeseed (Brassica napus L. var. Napus), flax (Linum usitatissimum L.), evening primrose (Oenothera biennis L.), milk thistle (Silybum marianum L. Gaertn.) and hemp (Cannabis sativa L.), was used to produce biochar. The experimental data have shown that the obtained biochar can have a calorific value of nearly 27 MJ kg−1. The use of pyrolysis allowed for a maximum increase in the calorific value of nearly 41% compared to non-thermally processed cakes and a several-fold decrease in carbon monoxide, nitrogen oxides and sulfur dioxide emissions. According to these results, it can be concluded that the pyrolysis process can be an attractive method for using residues from the production of various cooking oils to produce alternative biofuels, developing the potential of the circular economy.

Environmental impacts of shifts in surface urban heat island, emissions, and nighttime light during the Russia-Ukraine war in Ukrainian cities.

As recent geopolitical conflicts and climate change escalate, the effects of war on the atmosphere remain uncertain, in particular in the context of the recent large-scale war between Russia and Ukraine. We use satellite remote sensing techniques to establish the effects that reduced human activities in urban centers of Ukraine (Kharkiv, Donetsk, and Mariupol) have on Land Surface Temperatures (LST), Urban Heat Islands (UHI), emissions, and nighttime light. A variety of climate indicators, such as hot spots, changes in the intensity and area of the UHI, and changes in LST thresholds during 2022, are differentiated with pre-war conditions as a reference period (i.e., 2012-2022). Findings show that nighttime hot spots in 2022 for all three cities cover a smaller area than during the reference period, with a maximum decrease of 3.9% recorded for Donetsk. The largest areal decrease of nighttime UHI is recorded for Kharkiv (- 12.86%). Our results for air quality changes show a significant decrease in carbon monoxide (- 2.7%, based on the average for the three cities investigated) and an increase in Absorbing Aerosol Index (27.2%, based on the average for the three cities investigated) during the war (2022), compared to the years before the war (2019-2021). The 27.2% reduction in nighttime urban light during the first year of the war, compared to the years before the war, provides another measure of conflict-impact in the socio-economic urban environment. This study demonstrates the innovative application of satellite remote sensing to provide unique insights into the local-scale atmospheric consequences of human-related disasters, such as war. The use of high-resolution satellite data allows for the detection of subtle changes in urban climates and air quality, which are crucial for understanding the broader environmental impacts of geopolitical conflicts. Our approach not only enhances the understanding of war-related impacts on urban environments but also underscores the importance of continuous monitoring and assessment to inform policy and mitigation strategies.

Assessment of ammonia-diesel fuel blends on compression ignition engine performance and emissions using machine learning techniques

This study investigates the performance and emission characteristics of a multi-cylinder, naturally aspirated, compression ignition diesel engine using ammonia as a secondary fuel under full load conditions across various engine speeds. Ammonia dispersed with neat diesel at the concentration of 5, 10, and 15 liters per minutes via inlet manifold. Experimental tests assessed the impact of diesel-ammonia fuel mixtures at operating speeds of 1000 rpm to 3000 rpm. The performance metrics such as brake thermal efficiency, brake specific fuel consumption, exhaust gas temperature, and emissions characteristics were determined. Moreover, the study employed predictive models such a simple extraction, linear regression, and Long Short-Term Memory (LSTM) networks to analyze engine behaviour. The results demonstrated that increasing ammonia concentration improved brake thermal efficiency and reduced brake specific fuel consumption and exhaust gas temperature across all tested speeds. Specifically, ammonia additions led to significant decreases in carbon monoxide and carbon dioxide emissions due to reduced carbon content in the fuel mix, while nitrogen of oxides emissions presented a more complex pattern. Inclusion of the ammonia increases the NOx due to the inherent nitrogen content. Particulate matter emissions were also reduced, highlighting ammonia’s potential to mitigate particulate formation. Compared to difference prediction models, LSTM showed superior capability in capturing complex non-linear relationships and temporal dependencies in engine performance data, outperforming traditional linear models.

Impact of injection pressure on the performance, emissions, and combustion of a common rail direct injection engine fueled with quaternary blends

The scarcity and rising costs of fossil fuels, coupled with increasing pollution levels, have prompted the exploration of innovative biofuel blends. While binary and ternary fuels have been studied extensively in proportions of 5–20%, replacing up to 30–40% of fossil fuel dependency without significant engine modifications remains a challenge. One potential solution is to investigate an optimal quaternary blend (QB) through experimental methods. This study investigates the impact of increased injection pressure (IOP) and quaternary fuel blends on a common rail direct injection (CRDI) engine's performance and emissions. Different blends, including diesel fuel, vegetable oil, mahua methyl ester and normal-butanol, were tested to replace 30–40% of diesel and enhance combustion, reduce exhaust emissions and improve overall performance. Experiments used a 1-cylinder CRDI engine at high IOPs (400, 500, 600 and 700 bar). Results at 600 bar IOP showed that the optimal blend, QB3–QB4, increased brake thermal efficiency (BTE) by 9% and reduced brake-specific fuel consumption (BSFC) by approximately 11% compared to other blends. Emissions at 600 bar included a 16% reduction in hydrocarbons (HC) and a 24% decrease in carbon monoxide (CO) at full load. However, nitrogen oxide (NOx) emissions slightly increased with higher IOP. Significantly employing the QB3–QB4 blend at 600 bar improved control over HC, CO and smoke emissions. Overall, performance was enhanced and comparable to conventional diesel fuel, with only a minor increase in NOx emissions.

Impact of Using n-Octanol/Diesel Blends on the Performance and Emissions of a Direct-Injection Diesel Engine

This study evaluates the viability of n-octanol as an alternative fuel in a direct-injection diesel engine, aiming to enhance sustainability and efficiency. Experiments fueled by different blends of n-octanol with pure diesel were conducted to analyze their impacts on engine performance and emissions. The methodology involved testing each blend in a single-cylinder engine, measuring engine performance parameters such as brake torque and brake power under full-load conditions across a range of engine speeds. Comparative assessments of performance and emission characteristics at a constant engine speed were also conducted with varying loads. The results indicated that while n-octanol blends consistently improved brake thermal efficiency, they also increased brake-specific fuel consumption due to the lower energy content of n-octanol. Consequently, while all n-octanol blends reduced nitrogen oxide emissions compared to pure diesel, they also significantly decreased carbon monoxide, hydrocarbons, and smoke opacity, presenting a comprehensive reduction in harmful emissions. However, the benefits came with complex trade-offs: notably, higher concentrations of n-octanol led to a relative increase in nitrogen oxide emissions as the n-octanol ratio increased. The study concludes that n-octanol significantly improves engine efficiency and reduces diesel dependence, but optimizing the blend ratio is crucial to balance performance improvements with comprehensive emission reductions.

Enhanced atmospheric oxidation toward carbon neutrality reduces methane’s climate forcing

The hydroxyl radical (OH), as the central atmospheric oxidant, controls the removal rates of methane, a powerful greenhouse gas. It is being suggested that OH levels would decrease with reductions of nitrogen oxides and ozone levels by climate polices, but this remains unsettled. Here, we show that driven by the carbon neutrality pledge, the global-mean OH concentration, derived from multiple chemistry-climate model simulations, is projected to be significantly increasing with a trend of 0.071‒0.16% per year during 2015–2100. The leading cause of this OH enhancement is dramatic decreases in carbon monoxide and methane concentrations, which together reduce OH sinks. The OH increase shortens methane’s lifetime by 0.19‒1.1 years across models and subsequently diminishes methane’s radiative forcing. If following a largely unmitigated scenario, the global OH exhibits a significant decrease that would exacerbate methane’s radiative forcing. Thus, we highlight that targeted emission abatement strategies for sustained oxidation capacity can benefit climate change mitigation in the Anthropocene.

Effects of green synthesized copper oxide nanoparticle additive on diesel engine performance and emission characteristics

ABSTRACT The use of copper oxide nanoparticles (CuONPs) as an additive for diesel engines shows much promise in reducing emissions. Because copper is a transition metal, it helps reduce emissions by transferring heat from the engine to the exhaust. In this study, experimental research was carried out to find out the impact of copper oxide (CuO) made from Cherry laurel leaves (Prunus laurocerasus) extract on a diesel engine using a new green synthetic strategy. The existence of synthesized CuO was examined by UV, XRD, SEM, EDS, and FTIR. According to the green synthesis results, a CuO peak was obtained at 330 nm in the UV analysis. In addition, according to XRD, EDS, and SEM analyses, it was seen that CuO had a crystal and circular structure and consisted of 100% CuO. In engine experiments, CuONPs were mixed with diesel at different rates such as 10 ppm and 15 ppm. In the results, the D100 + 15 ppm CuO mix shows a notable decrease in carbon monoxide (CO) and hydrocarbon (HC) emissions 45.9% and 19.57%, compared to pure diesel at 2000W. Moreover, it was revealed that the brake specific fuel consumption (BSFC) of the D100 + 15 ppm CuO mixture at 3000 W decreased by 1.80% compared to diesel. However, both smoke and NOx increased with nanoparticles as compared to diesel.

Two- and 3-year outcomes in convalescent individuals with COVID-19: A prospective cohort study.

As the long-term consequences of coronavirus disease 2019 (COVID-19) have not been defined, it is necessary to explore persistent symptoms, long-term respiratory impairment, and impact on quality of life over time in COVID-19 survivors. In this prospective cohort study, convalescent individuals diagnosed with COVID-19 were followed-up 2 and 3 years after discharge from hospital. Participants completed an in-person interview to assess persistent symptoms and underwent blood tests, pulmonary function tests, chest high-resolution computed tomography, and the 6-min walking test. There were 762 patients at the 2-year follow-up and 613 patients at the 3-year follow-up. The mean age was 60 years and 415 (54.5%) were men. At 3 years, 39.80% of the participants had at least one symptom; most frequently, fatigue, difficulty sleeping, joint pain, shortness of breath, muscle aches, and cough. The participants experienced different degrees of pulmonary function impairment, with decreased carbon monoxide diffusion capacity being the main feature; results remained relatively stable over the 2-3 years. Multiple logistic regression analysis demonstrated that female sex and smoking were independently associated with impaired diffusion capacity. A subgroup analysis based on disease severity was performed, indicating that there was no difference in other parameters of lung function except forced vital capacity at 3-year follow-up. Persistent radiographic abnormalities, most commonly fibrotic-like changes, were observed at both timepoints. At 3 years, patients had a significantly improved Mental Component Score compared with that at 2 years, with a lower percentage with anxiety. Our study indicated that symptoms and pulmonary abnormalities persisted in COVID-19 survivors at 3 years. Further studies are warranted to explore the long-term effects of COVID-19 and develop appropriate rehabilitation strategies.

Investigating the Effects of Environmentally Friendly Additives on the Exhaust Gas Composition and Fuel Consumption of an Internal Combustion Engine

This article shows the effect of the addition of effective microorganisms and silver on the exhaust gas composition and fuel consumption. Exhaust emission standards are becoming increasingly stringent, which makes it difficult for engine manufacturers to meet them. For this reason, intensive work is underway to use alternative propulsion systems on ships, and for diesel engines, alternative fuels. Among other things, this applies to mixtures of petroleum-based fuels with vegetable oils and their esters. Unfortunately, their use, due to their physicochemical properties, can negatively affect the performance of the engine and the wear of its components. Therefore, the aim of this study was to see how additives of effective microorganisms in the form of ceramic liquid and tubes, and a silver solution and colloidal silver would affect some engine parameters, including the exhaust gas composition and fuel consumption. The authors are not aware of the results of previous research on this issue. The tests were carried out on a diesel engine for four types of green additives at concentrations of 2% and 5%, at different ranges of its load. The additives added to the diesel fuel were characterised, and the test stand was presented, along with the parameters of the tested fuel. The effect of additives on selected engine parameters, including fuel consumption, was presented. The characteristics of hourly fuel consumption and selected components of the exhaust gas, including nitrogen oxides, carbon monoxide and carbon dioxide as a function of the concentration of ecological additives are shown and analysed. It was found that the most beneficial additive that had a positive effect on the exhaust gas composition and fuel consumption was a silver solution in a 2% concentration. There was a decrease of up to 4% in the NOx content of the exhaust gas, a decrease in carbon monoxide of more than 28%, a decrease in carbon dioxide of 4.6% and a decrease in fuel consumption of around 3% was achieved under the tested conditions. The use of these additives is an innovative solution that has a positive impact on reducing the emissions of harmful compounds into the atmosphere. In further research, it will be necessary to study the effect of this additive on the combustion process in the engine and the wear of its components, as well as to confirm the results obtained in real operating conditions.

Investigation of the effects of single and double-walled carbon nanotube utilization on diesel engine combustion, emissions, and performance

In this study, single-walled carbon nanotubes (SWCNT) and double-walled carbon nanotubes (DWCNT) were separately added to diesel fuel to investigate their effects on the combustion, performance, and emission characteristics of a diesel engine. SWCNT and DWCNT were added to diesel fuel at concentrations of 100 mg/L with the assistance of ultrasonication, resulting in the creation of DFCNT-1 and DFCNT-2 fuels. Fuel samples were tested at 1500 rpm under varying load conditions. The results indicated significant increases in combustion parameters such as cylinder pressure (CP), Net Heat Release Rate (NHRR), Rate of Pressure Rise (ROPR), Cumulative Heat Release (CHR), and average gas temperature (MGT) for DFCNT-1 and DFCNT-2 fuels. Additionally, the use of DFCNT-1 and DFCNT-2 fuels led to a decrease in carbon monoxide and smoke emissions while nitrogen oxide and carbon dioxide emissions increased. The Brake Specific Fuel Consumption (BSFC) decreased by 7.59% and 4.29% with the use of DFCNT-1 and DFCNT-2, respectively. Moreover, a shorter ignition delay (ID) and combustion duration (CD) were observed with DFCNT-1 and DFCNT-2 fuels. Overall, it was concluded that the addition of SWCNT was more effective than DWCNT in terms of combustion efficiency, performance, and emissions.

Synergistic effects of nano-enhanced waste transformer oil and hydrogen premixing on CI engine performance and emissions

Waste materials possess untapped potential when harnessed effectively. One such resource is waste transformer oil, derived from electrical transformers, which can be converted into a valuable fuel source for compression-ignition (CI) engines using pyrolysis techniques. In this study, we explored the utilization of a 50 % blend of waste transformer oil with diesel, augmented with Titanium dioxide nanoparticles (referred to as “nano fuel of waste transformer oil”), in an unmodified CI engine. To further enhance the performance of this nano fuel, we introduced hydrogen (at flow rates of 2.5 LPM, 5.0 LPM, and 7.5 LPM) into the inlet section during the suction phase, promoting premixing within the cylinder. Hydrogen premixing significantly improved combustion dynamics. Notably, when 7.5 LPM of hydrogen was introduced alongside waste transformer oil-derived nano fuel, a remarkable 37.30 % increase in brake thermal efficiency was achieved. Moreover, this configuration exhibited a 15.33 % reduction in brake-specific fuel consumption (BSFC), a 27.09 % decrease in carbon monoxide (CO) emissions, a 37.50 % decrease in unburned hydrocarbon (UHC) emissions, and a 28.53 % reduction in smoke opacity compared to traditional diesel operation. These results highlight the potential for enhanced CI engine performance and reduced emissions through the strategic combination of waste transformer oil-based nano-fuel and hydrogen premixing. Consequently, we recommend further exploration of hydrogen premixing in conjunction with nano-enhanced waste transformer oil for superior CI engine performance.

Experimental Investigation of Compression Ignition Engine Combustion, Performance, and Emission Characteristics of Ternary Blends with Higher Alcohols (1-Heptanol and n-Octanol)

Concerns about the depletion of petroleum reserves and rising pollution led researchers to search for alternate and environmentally compatible fuels for compression ignition engines. As an excellent alternative fuel additive to biodiesel–diesel blends, higher alcohol exhibits outstanding fuel properties (such as high energy content and cetane number) and can operate in diesel engines without requiring engine changes. This study focuses on investigating the ternary blends comprising higher alcohols, namely 1-heptanol and n-octanol, in hybrid biodiesel (animal fat oil–rice bran oil–cottonseed oil) and diesel on compression ignition engine characteristics. The performance, combustion, and emissions of a diesel engine fuelled with mono (D100), binary (B20), and ternary fuel blends (B20H10, B20H20, B20O10, and B20O20) were analysed at a constant engine speed of 1500 rpm. The test fuels met the American Society for Testing and Materials standards for fuel properties and exhibited stable behaviour during testing. Experimental results showed that at 100% load, the least brake-specific fuel consumptions for diesel fuel, B20, B20H10, B20H20, B20O10, and B20O20 were 254.1 g/kWh, 302.14 g/kWh, 281.25 g/kWh, 310.94 g/kWh, 292.8 g/kWh, and 313.80 g/kWh, respectively. Meanwhile, the maximum brake thermal efficiency values were obtained as 38.65%, 37.01%, 37.76%, 36.84%, 37.12%, and 36.38%, respectively. At 100% load, the peak heat release rates for diesel, B20, B20H10, B20H20, B20O10, and B20O20 were found to be 64.65 J/deg, 59.07 J/deg, 62.34 J/deg, 56.12 J/deg, 57.95 J/deg, and 51.9 J/deg, respectively. The addition of 1-heptanol and n-octanol as oxygenated additives into the ternary blend resulted in decreased carbon monoxide and unburned hydrocarbon emissions while increasing carbon dioxide and nitrous oxide emissions compared to diesel fuel. Overall, the study concludes that ternary blends with 1-heptanol and n-octanol as additives improve performance and combustion behaviour and reduce exhaust emissions compared to binary blends.

Theoretical investigation of combustion and emissions of CI engines fueled by various blends of depolymerized low-density polythene and diesel with co-solvent additives

The depletion of fossil fuels and the accumulation of plastic waste are both serious issues facing the world today. This study investigated the potential use of plastic waste as an alternative fuel by utilizing diesel (D) to depolymerize low-density polyethylene (LDPE) in the presence of co-solvents. Several co-solvents were examined: a-pinene, toluene, and o-xylene, with ratios of 10% weight in the LDPE/diesel blend. The blends were theoretically tested in a diesel engine to investigate the impact on the combustion characteristics and emissions. According to tested data, the in-cylinder peak pressure and temperature decreased within the blend of D/LDPE in comparison to diesel at all engine loads. However, when co-solvents were added to the D/LDPE blend, in-cylinder pressures increased during the combustion at all loads, with improvements of 0.48%, 0.5%, 0.6%, and 0.4% for the blends of D/LDPE (10% toluene and 1 bar), D/LDPE (10% a-pinene and 1 bar), D/LDPE (10% xylene and 1 bar), and D/LDPE (10% xylene and 10 bar), respectively, in comparison with diesel at 100% load. Co-solvent additions such as a-pinene and o-xylene to the plastic/diesel blend resulted in a substantial and gradual increase in the heat release rate at high loads. In respect to emissions, carbon monoxide, unburnt hydrocarbon, and soot levels were raised by adding LDPE plastic to D and reduced by adding co-solvents. The most effective co-solvents for decreasing carbon monoxide, unburnt hydrocarbon, and soot emissions were pinene, followed by xylene.

Experimental probe into an automative engine run on waste cooking oil biodiesel blend at varying engine speeds

The present work attempts to evaluate the performance of an automotive diesel engine run on waste cooking oil biodiesel (WCO) blend at variable engine speeds. The composition of the blend (B40) used in the study is 40% WCO and 60% diesel by volume and the engine used for the experimentation is a naturally aspirated, water-cooled and direct injection type having a compression ratio of 18:1. The engine settings used in the study are an injection timing (IT) of 150bTDC and a fuel injection pressure (IP) of 500 bar. The performance and emissions characteristics of the automotive engine are studied at various loads of 20%, 40%, 60%, 80% and 100% and at different engine speeds of 1500, 1800 and 2400 rpm. The first two rotational speeds are chosen to study the stationary power generation capabilities of the blend, while the feasibility of blend for automotive applications has been evaluated at 2400 rpm. Experiments have also been conducted on the engine run on mineral diesel fuel in order to make a comparative analysis. At full load, the maximum brake thermal efficiency (BTE) is found to be 21.51%, 25.48% and 23.56% for the blend at 1500, 1800 and 2400 rpm, respectively. At 2400 rpm and at 20% and 40% loads, the blend shows an absolute improvement in BTE of 0.17% and 0.03%, respectively over diesel fuel. On an average, there is a decrease of carbon monoxide (CO) emissions by 87.5%, 22.22% and 14.28% at 1500, 1800 and 2400 rpm as compared to diesel fuel. At 1500 and 2400 rpm, there is an average absolute increase in hydrocarbon (HC) emissions by 1.6 ppm and 9.6 ppm, respectively; while at 1800 rpm, an average decrease in HC emissions by 4 ppm is observed vis-a-vis diesel fuel. While emissions of oxides of nitrogen (NOx) as compared to diesel fuel increased on an average by 19.43%, 26.09% and 1.01% at 1500, 1800 and 2400 rpm, respectively.

Effect of Inlet Air Temperature on HCCI Engine Fuelled with Diesel- Eucalyptus Fuel Blends

Abstract: In this study, port injection single-cylinder HCCI engines were used to conduct an experimental investigation into the impact of diesel-Eucalyptus fuel blends on HCCI engine performance and exhaust pollutants. In the tests, eucalyptus and diesel were blended in a variety of volume ratios as test fuels, including 20% eucalyptus to 80% diesel (Eu20/D80), 40% eucalyptus to 60% diesel (Eu40/D60), 60% eucalyptus to 40% diesel (Eu60/D40), and 100% diesel. The tests were performed at a 1500 rpm engine speed with a 19-compression ratio at inlet air temperatures between 70° and 130°C. This study observed at the variations in brake thermal efficiency, exhaust gas temperature, and carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) emissions. According to test results, HCCI with diesel-Eucalyptus fuel blends increases brake thermal efficiency, exhaust gas temperature, decreases carbon monoxide, unburned hydrocarbons at inlet temperatures of 130°C, and decreases nitrogen oxides at inlet temperatures of 70°C. It was subsequently found that diesel-Eucalyptus fuel mixtures significantly affected the output and exhaust emissions of HCCI engines.

Investigation on combustion characteristics and gas emissions of a high-pressure direct-injection natural gas engine at different combustion modes

In the present study, the potential of natural gas pre-injection, mixing-limited combustion, and slightly premixed combustion modes were evaluated to achieve high thermal efficiency and low nitrogen oxides and carbon monoxide emissions. To this end, a dual direct injection model was established to perform numerical simulations. The obtained results revealed that in the natural gas pre-injection mode, the optimized natural gas pre-injection proportion and injection interval between the end of natural gas pre-injection and the start of diesel injection can significantly reduce carbon monoxide emissions and improve indicated thermal efficiency with a slight increase in nitrogen oxides. In the mixing-limited combustion mode, combustion phasing and indicated thermal efficiency are not sensitive to the variations of the injection interval between diesel and natural gas. Moreover, a larger injection interval between diesel and natural gas is beneficial to reduce carbon monoxide. In the slightly premixed combustion mode, as the injection interval between diesel and natural gas decreases, combustion phasing delays, carbon monoxide emissions reduce, and nitrogen oxides emissions increase first and then decrease. Advancing the start of natural gas injection increases maximum pressure rise rate and nitrogen oxides in both natural gas mixing-limited combustion and slightly premixed combustion modes but decreases carbon monoxide dramatically. The natural gas mixing-limited combustion mode has more potential to meet carbon monoxide limits imposed by the Euro VII standard with no need for extra after-treatment devices while improving thermal efficiency.

Exhaust emission reduction of a SI engine using acetone–gasoline fuel blends: Modeling, prediction, and whale optimization algorithm

Acetone–gasoline fuel is one potential favorable alternative option to regular gasoline fuel. This work attempts to mitigate pollution while simultaneously improving SI engine performance with acetone (AC) proportion in fuel mixture and varying engine speed. Acetone–gasoline alternative fuel was experimentally prepared by mixing 5–10 vol.% of acetone into ordinary gasoline. The experiments were performed in a spark ignition (SI) single-cylinder, four-stroke at variable engine speed. The engine performance was measured by an eddy current dynamometer (ECD), while the exhaust engine was measured by a gas analyzer connected to the gasoline engine. The proposed strategy, the integrated combined polynomial regression with whale optimization algorithm (WOA), was implemented. The results showed that the acetone blending of 10 % with gasoline (AC10: 10 vol. % acetone + 90 vol. % gasoline) decreases carbon monoxide (CO), unburned hydrocarbon (UHC), and nitrogen oxides (NOx), emissions by 26.3%, 30.3%, and 6.6%, respectively. Furthermore, the AC10 exhibited better engine brake power (BP) than pure gasoline, with an improvement of 4.39%. According to the optimization results, the BP was enhanced by AC10 to record 2.426 kW at 2887 rpm. In addition, engine emissions reduced to the lowest levels of 142.849 ppm, 0.426%, and 1088.178 ppm, in terms of UHC, CO, and NOx, respectively. The experiment results show that the WOA optimizer can accurately predict the optimal point in SI engine performance and emissions.

Recent advancement in the application of metal based nanoadditive in diesel/biodiesel fueled compression ignition engine: A comprehensive review on nanofluid preparation and stability, fuel property, combustion, performance, and emission characteristics

AbstractBiodiesel has emerged as a promising renewable fuel, which can help reduce dependency on fossil fuel and has potentiality to replace petrodiesel partially. Usage of biodiesel results in decreased carbon monoxide, hydrocarbon, and particulate matter emission. However, it has some drawbacks such as increased nitrogen oxides (NOx) emission, lower calorific value, and poor engine performance, which restrict wide usage of biodiesel as a potential substitute in compression ignition engine. There is a scope to overcome these problems by applying metal based nanoparticles (NPs) as fuel additive. This article reviews the preparation and stability of nanofluid and the effect of metal based NPs on fuel properties, combustion, performance, and emission characteristics. It has been concluded that inclusion of nanoadditives increases cetane number and calorific value of blended fuel. According to the most authors, metal based NP doped biodiesel blend enhances ignition characteristics, improves engine performance, and reduces emissions including NOx compared to biodiesel blend without additive. However, some concerns and challenges identified in this article need to be addressed to make this technology feasible for commercial application in near future.

Influences of Iron Oxide Nanomaterial and Hydrogen Addition into Sunflower Biodiesel/Diesel Powered Diesel Engine Performance and Emissions

AbstractIn this study, effects of iron oxide (Fe3O4) and hydrogen (H2) additions into 20% sunflower biodiesel + 80% diesel (B20) operated compression ignition engine performance and emissions are evaluated. Diesel fuel (D) is selected as a reference fuel for comparison purpose. Reduced performance level with B20 can be recovered with use of nanoparticle and hydrogen due to their superior combustion characteristics. In comparison to diesel, B20 mixture has caused to reduction on power by 6.44% while addition of nanoparticle and hydrogen (H_B20_Fe) have increased power by 5.76%. B20 mixture led to decrease carbon monoxide (CO) emission by 7.92% whereas nanoparticle and hydrogen addition have caused further decrement by 12.35% compared to diesel. Diesel shows best nitrogen oxides (NOx) emission characteristics of all. Increment levels are 7.24% and 12.94 for B20 and H_B20_Fe, respectively.