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1.
Heliyon ; 10(16): e35820, 2024 Aug 30.
Article in English | MEDLINE | ID: mdl-39220977

ABSTRACT

As the world moves away from fossil fuels and embraces sustainable energy sources, the need for sustainable fuels for transportation becomes paramount. This study investigates the effects of pyrolysis oil derived from cassava peel waste (CPO), hydrogen (H), and diesel (D) blends as a partial substitute for low-displacement compression ignition engines. We tested three blends - CPO25, CPO25H5, and CPO25H10 - against neat diesel operation at engine speeds of 3400 rpm, 3600 rpm, and 3800 rpm and torques of 4 Nm, 6 Nm, and 8 Nm. Our findings reveal that while energy efficiency decreased with CPO25 compared to D100 operation, adding H2 increased energy efficiency. The highest increase was 7.8 % for CPO25H5 and 16 % for CPO25H10 compared to CPO25. Exergy efficiency also decreased with CPO25 compared to D100, but adding H2 compensated for this reduction. The highest increase was 8.0 % for CPO25H5 and 17 % for CPO25H10 compared to D100. CPO25H10 showed an increase of 8.1 % in combustion pressure and 9.9 % in heat release rate compared to CPO25. Emissions analysis also revealed that CO emissions were considerably lower with CPO and H2 than with D100, with the highest decrease of 11 % with CPO25H10. CO2 and hydrocarbon emissions followed the same trend as CO. Although NOx emissions slightly increased, the benefits of using pyrolysis oil-H2-diesel blends as a partial substitution fuel for low-displacement compression ignition engines are evident.

2.
Ecotoxicol Environ Saf ; 284: 116997, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39260215

ABSTRACT

Due to the complexity of environmental exposure factors and the low levels of exposure in the general population, identifying the key environmental factors associated with diabetes and understanding their potential mechanisms present significant challenges. This study aimed to identify key polycyclic aromatic hydrocarbons (PAHs) contributing to increased fasting blood glucose (FBG) concentrations and to explore their potential metabolic mechanisms. We recruited a highly PAH-exposed diesel engine exhaust testing population and healthy controls. Our findings found a positive association between FBG concentrations and PAH metabolites, identifying 1-OHNa, 2-OHPh, and 9-OHPh as major contributors to the rise in FBG concentrations induced by PAH mixtures. Specifically, each 10 % increase in 1-OHNa, 2-OHPh, and 9-OHPh concentrations led to increases in FBG concentrations of 0.201 %, 0.261 %, and 0.268 %, respectively. Targeted metabolomics analysis revealed significant alterations in metabolic pathways among those exposed to high levels of PAHs, including sirtuin signaling, asparagine metabolism, and proline metabolism pathway. Toxic function analysis highlighted differential metabolites involved in various dysglycemia-related conditions, such as cardiac arrhythmia and renal damage. Mediation analysis revealed that 2-aminooctanoic acid mediated the FBG elevation induced by 2-OHPh, while 2-hydroxyphenylacetic acid and hypoxanthine acted as partial suppressors. Notably, 2-aminooctanoic acid was identified as a crucial intermediary metabolic biomarker, mediating significant portions of the associations between the multiple different structures of OH-PAHs and elevated FBG concentrations, accounting for 16.73 %, 10.84 %, 10.00 %, and 11.90 % of these effects for 1-OHPyr, 2-OHFlu, the sum concentrations of 2- and 9-OHPh, and the sum concentrations of total OH-PAHs, respectively. Overall, our study explored the potential metabolic mechanisms underlying the elevated FBG induced by PAHs and identified 2-aminooctanoic acid as a pivotal metabolic biomarker, presenting a potential target for intervention.

3.
Sci Rep ; 14(1): 19157, 2024 Aug 19.
Article in English | MEDLINE | ID: mdl-39160253

ABSTRACT

The reliability and safety of locomotives is crucial for efficient train operation. Repeated turbocharger failures in Israel Railways locomotive fleet have raised serious safety concerns. An investigation into the failures revealed that the uncontrolled acceleration and overspeed transients of the turbocharger shaft occurred before the failure. Early detection of potential turbocharger failures by predicting overspeed conditions is critical to the safety and reliability of locomotives. In this study, an enhanced novel algorithm for estimating the Instantaneous Angular Speed (IAS) of the turbocharger and diesel engines is presented to overcome the challenges of transient operating conditions of diesel engines. Using adaptive dephasing, the algorithm effectively isolates critical asynchronous vibration components that are crucial for the early detection of turbocharger failures. This algorithm is suitable for non-stationary speeds and is applicable to any range of rotational speed and rate of change. The algorithm requires the input of the basic parameters of the system, while all other parameters that control the process are determined automatically. The algorithm was developed specifically for the special operating conditions of diesel engines and improves predictive maintenance and operational reliability. The method is robust as it correlates between several characteristic frequencies of the rotating parts of the system. The algorithm was verified and validated with simulated and experimental data.

4.
Heliyon ; 10(15): e34959, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39166063

ABSTRACT

In a variety of industries, including transportation, agriculture, and manufacturing, diesel engines are often employed. Due of rising prices and environmental concerns, researchers examined whether biodiesels might replace diesel. The current study looks into American Saffron Oil's feasibility as a feedstock for biodiesel production. The transesterification technique is used to extract American saffron oil methyl este(ASOME), which is then examined for its physical and chemical properties in accordance with ASTM standards. Diesel fuel and American Saffron Oil methyl ester are mixed on a volume basis to create a variety of fuel blends, including B20, B40, and B60. The test results showed that the 20 % ASOME mix had better performance and reduced emissions. Also, utilizing DIESEL-RK simulation software, diesel engine tests are conducted for the B20, B40, and B60 under identical operating circumstances. Moreover, diesel engine testing for the B20, B40, and B60 are carried out using DIESEL-RK simulation software under comparable operating circumstances. Results of simulation software tests show improved engine performance and reduced pollutants. When experimental data is compared to DIESEL-RK modeling software, it is found that brake thermal efficiency increased by 5.7 % and emissions of hydrocarbon and carbon monoxide decreased by 2.5 % and 14.3 %, respectively.

5.
Heliyon ; 10(15): e35010, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39170269

ABSTRACT

The main objective of the paper is to reveal a few aspects related to combustion quality of a diesel engine fueled in diesel-gas mode with diesel fuel and compressed natural gas. The total amount of heat released per cycle will be higher when the engine is fueled in dual-fuel mode due to higher LHV and because of the gaseous state of CNG. For low and medium loads the total quality of heat released per cycle will increase with 10 % and for higher loads it will reach levels with 25 % higher. The heat release rate of the preformed mixture will double its value for low and medium loads and will reach thresholds up to 3.5 times higher (interval -15; -5°CA); admitting CNG into cylinder will help the preformed mixture to reach stoichiometric values and thus improving the fast combustion phase. Fueling the engine in dual fuel mode with diesel fuel and CNG will have a negative effect on the maximum heat release rate; there will be a 10 % drop in maximum HRR for low loads when the energetic substitution coefficient reaches 36 % and 14 % at high loads when the xc is 26 %. The gaseous state and a higher LHV of CNG will have a good impact on indicated mean effective pressure for all studied regimes when the engine is fueled in DG mode: for low and medium loads 30 % and for high loads 20 % increase will be recorded. Gaseous state of CNG will lead to a higher percentage of preformed mixture and thus the fast combustion phase will extend for longer periods for all studied regimes when the engine is fueled in DG mode (20 % longer for low and medium loads and 30 % for high loads). The diffusive combustion phase will become shorter due to a lower quantity of the main dose when CNG is injected into the intake manifold (10-15 % shorter for low loads and 7 % at high loads).

6.
Heliyon ; 10(15): e34216, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39170566

ABSTRACT

The primary focus of this study is the validation of composite additives with the help of additional optimization methods and the analysis of its effect on the combustion characteristics of compression ignition (CI) engines. Previous work on the identification of the correct multi additive combination by Taguchi and the TOPSIS optimization method has shown substantial improvements in the performance and emission characteristics of CI engines. The same work was extended using the GRA Optimization method with the Multi-Criteria Decision-Making (MCDM) optimization technique known as the Analytic Hierarchy Process (AHP) to validate the optimization results from the previous optimization work. Remarkably, all optimization methods yielded consistent results, pointing to the superiority of the composite additive sample 'D8EH6E4 hence supporting the outcome of previous work. Subsequent testing and comparison of this novel composite additive with baseline diesel fuel for combustion characteristics analysis demonstrated notable improvements in combustion parameters, including a 25 % reduction in the rate of pressure rise, an 18 % decrease in net heat release rate, and a 6 % decrease in mean gas temperature.

7.
Ann Work Expo Health ; 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-39102900

ABSTRACT

Diesel engine exhaust (DEE) is carcinogenic and potentially hazardous for those working in close proximity to diesel-powered machines. This study characterizes workplace exposure to DEE and its associated particulate matter (PM) during outdoor construction activities. We sampled at 4 construction sites in the Copenhagen metropolitan area. We used portable constant-flow pumps and quartz-fiber filters to quantify personal exposure to elemental carbon (EC), and used real-time instruments to collect activity-based information about particle number and size distribution, as well as black carbon (BC) concentration. Full-shift measurements of EC concentration ranged from < 0.3 to 6.4 µg/m3. Geometric mean (GM) EC exposure was highest for ground workers (3.4 µg/m3 EC; geometric standard deviation, GSD = 1.3), followed by drilling rig operators (2.6 µg/m3 EC; GSD = 1.4). Exposure for non-drilling-rig machine operators (1.2 µg/m3 EC; GSD = 2.9) did not differ significantly from background (0.9 µg/m3 EC; GSD = 1.7). The maximum 15-min moving average concentration of BC was 17 µg/m3, and the highest recorded peak concentration was 44 µg/m3. In numbers, the particle size distributions were dominated by ultrafine particles ascribed to DEE and occasional welding activities at the sites. The average total particle number concentrations (PNCs) measured in near-field and far-field positions across all worksites were 10,600 (GSD = 3.0) and 6,000 (GSD = 2.8)/cm3, respectively. Sites with active drilling rigs saw significantly higher average total PNCs at their near-field stations (13,600, 32,000, and 9,700/cm3; GSD = 2.4, 3.4, and 2.4) than sites without (4,700/cm3; GSD = 1.6). Overall, the DEE exposures at these outdoor construction sites were below current occupational exposure limits for EC (10 µg/m3 in Denmark; 50 µg/m3 in the European Union), but extended durations of exposure to the observed DEE levels may still be a health risk.

8.
Reprod Toxicol ; 129: 108682, 2024 Oct.
Article in English | MEDLINE | ID: mdl-39117124

ABSTRACT

The possible vulnerability of the male reproductive system to environmental pollutants such as air pollution necessitates a thorough investigation of the underlying mechanisms involved in the dysregulation of male reproductive function. The present study was designed to investigate the influence of the filtered fraction of diesel exhaust (predominantly comprising gases) on male reproductive function in Wistar rat model. Adult male rats were randomly assigned into three groups (n=8/group): Control (unexposed) group (CG-A), the Clean air group in WBE chamber (CAG-A), and Filtered diesel exhaust group in WBE chamber (FDG-A). The exposure protocol for CAG-A and FDG-A was 6 h/day x 5d/week x 6 weeks,evaluation of sperm parameters, testicular histopathology, quantification of hormones (testosterone, LH, FSH, 17ß-Estradiol, and prolactin), and GST levels were performed. Results showed that WBE to FDE leads to a significant decline in sperm concentration (p=0.008, CG-A vs FDG-A; p=0.014, CAG-A vs FDG-A), motility (p=0.008, CG-A vs FDG-A; p=0.029, CAG-A vs FDG-A), serum testosterone (p=0.024, CG-A vs FDG-A; p=0.007, CAG-A vs FDG-A), testicular testosterone (p=0.008, CG-A vs FDG-A; p=0.028, CAG-A vs FDG-A), 17ß-Estradiol (p=0.007, CG-A vs FDG-A), and GST levels (p=0.0002, CG-A vs FDG-A; p=0.0019, CAG-A vs FDG-A). These findings demonstrate the disruption of testosterone-estradiol balance in the intratesticular milieu without significant alterations in other principal pituitary hormones in adult rats exposed to FDE. The predominant presence of gaseous components in FDE can cause testicular damage due to oxidative imbalance. This underscores the causality of FDE exposure and impaired male reproductive outcomes.


Subject(s)
Air Pollutants , Glutathione Transferase , Rats, Wistar , Spermatozoa , Testis , Vehicle Emissions , Animals , Male , Vehicle Emissions/toxicity , Testis/drug effects , Testis/pathology , Testis/metabolism , Glutathione Transferase/metabolism , Spermatozoa/drug effects , Air Pollutants/toxicity , Sperm Motility/drug effects , Testosterone/blood , Sperm Count , Estradiol/blood , Rats , Follicle Stimulating Hormone/blood , Luteinizing Hormone/blood
9.
Sci Total Environ ; 951: 175469, 2024 Nov 15.
Article in English | MEDLINE | ID: mdl-39153615

ABSTRACT

Exposure to traffic-related air pollution and ultrafine particles (<100 nm; UFP) is linked with neurodegeneration. However, the impact of the aromatic content in fuels and the contribution of different fractions of UFP, i.e., solid UFP vs SVOC UFP, on neuronal function is unknown. We therefore studied effects on neuronal activity and viability in rat primary cortical cells exposed for up to 120 h to copper oxide particles (CuO) or UFP (solid and SVOC) emitted from a heavy-duty diesel engine fueled with petroleum diesel (A20; 20 % aromatics) or Hydrotreated Vegetable Oil-type fuel (A0; 0.1 % aromatics), or solid UFP emitted from a non-road Kubota engine fueled with A20. Moreover, effects of UFP and CuO upon simulated inhalation exposure were studied by exposing an lung model (Calu-3 and THP-1 cells) for 48 h and subsequently exposing the cortical cells to the medium collected from the basal compartment of the lung model. Additionally, cell viability, cytotoxicity, barrier function, inflammation, and oxidative and cell stress were studied in the lung model after 48 h exposure to UFP and CuO. Compared to control, direct exposure to CuO and SVOC UFP decreased neuronal activity, which was partly associated with cytotoxicity. Effects on neuronal activity upon direct exposure to solid UFP were limited. A20-derived UFP (solid and SVOC) were more potent in altering neuronal function and viability than A0 counterparts. Effects on neuronal activity from simulated inhalation exposure were minor compared to direct exposures. In the lung model, CuO and A20-derived UFP increased cytokine release compared to control, whereas CuO and SVOC A20 altered gene expression indicative for oxidative stress. Our data indicate that SVOC UFP exhibit higher (neuro)toxic potency for altering neuronal activity in rat primary cortical cells than the solid fraction. Moreover, our data suggest that reducing the aromatic content in fuel decreases the (neuro)toxic potency of emitted UFP.


Subject(s)
Air Pollutants , Inhalation Exposure , Particulate Matter , Vehicle Emissions , Vehicle Emissions/toxicity , Vehicle Emissions/analysis , Particulate Matter/toxicity , Rats , Animals , Air Pollutants/toxicity , Air Pollutants/analysis , Neurons/drug effects , Particle Size , Copper/toxicity , Cell Survival/drug effects
10.
Article in English | MEDLINE | ID: mdl-39088172

ABSTRACT

The introduction of hydrogen into the engine could enhance its combustion efficiency and emission characteristics. The current study examines the attributes of compression ignition (CI) engines by introducing hydrogen into a biodiesel blend derived from algae. The improved thermal properties of hydrogen, when combined with algae biodiesel, significantly affect the performance, combustion, and emissions of dual-fuel engines. A study was conducted to evaluate the impact of hydrogen enrichment levels of 5%, 10%, 15%, and 20% of the nozzle volume on a biodiesel blend fuel. In comparison to diesel, algal biodiesel reduces emissions of unburned hydrocarbons (HC), carbon monoxide (CO), and oxygen (O2) by 5.19%, 3.61%, and 2.83%, respectively, while increasing nitrogen oxide (NO) emissions by 4.73%. In contrast to biodiesel, diesel demonstrated superior brake thermal efficiency (BTE) and lower specific energy consumption (SEC). Injecting hydrogen into A20 blend fuel at volumes of 5%, 10%, 15%, and 20% results in a respective increase in brake thermal efficiency of 2.65%, 2.97%, 3.50%, and 4.15%. The addition of hydrogen gas to biodiesel blends further enhances their combustion qualities, leading to elevated peak cylinder pressure, temperature, and heat release rate. The results indicate that A20H5, A20H10, A20H15, and A20H20 fuel reduced CO emissions by 3.75%, 8.75%, 12.5%, and 16.25%, respectively, compared to the A20 blend. In the same vein, HC emissions decreased by 5.76%, 10.29%, 15.52%, and 18.98%, respectively, as compared to A20 fuel. However, NO emissions rose by 5.36%, 10.20%, 15.28%, and 23.23%, respectively, for A20H5, A20H10, A20H15, and A20H20 test fuels. Ultimately, the utilization of algal biodiesel and hydrogen enrichment in diesel engines was proven to substantially reduce pollutants while increasing efficiency. This study contributes valuable insights into the intersection of renewable fuels, hydrogen enrichment, and engine technology, with the potential to drive significant advancements in sustainable transportation and environmental conservation.

11.
Environ Sci Pollut Res Int ; 31(32): 45105-45116, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38958858

ABSTRACT

Diesel soot is a significant contributor to air pollution. Soot particles present in diesel engine exhaust have a negative impact on the environment and human health. Diesel oxidation catalysts (DOCs) and diesel particulate filters (DPFs) currently use noble metal-based catalysts for soot oxidation. Due to the use of noble metals in the catalyst, the cost of diesel after-treatment systems is steadily rising. As a result, diesel vehicles have become commercially less viable than gasoline vehicles and electronic vehicles. The study focuses on an alternative diesel oxidation catalyst with efficiency similar to that of a noble metal catalyst but with a much lower cost. CeO2-Al2O3 catalysts are known for their oxygen storage capacity and high redox activity, making them suitable for soot oxidation. Adding Zr to these catalysts has been shown to influence their structural and chemical properties, significantly affecting their catalytic behavior. Therefore, the current study is focused on using Zr/CeO2-Al2O3 as a substitute for noble metal-based catalysts to enhance its performance for diesel soot oxidation in automotive exhaust. Evaporation-induced self-assembly (EISA) was used to prepare 1, 3, and 5 weight (wt) % Zr supported mesoporous CeO2-Al2O3 catalysts. Morphological, structural, and physicochemical properties of the synthesized catalysts were examined using Brunauer-Emmett-Teller (BET) absolute isotherm, Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Temperature programmed reduction (TPR), and Temperature-programmed desorption of ammonia (NH3-TPD). XRD, BET, and SEM data confirmed that the catalysts were mesoporous and low-crystalline with a high surface area. The soot oxidation activity of the catalysts was evaluated using a thermogravimetric analysis (TGA) technique. The loose contacts soot oxidation activity test suggested that 50% oxidation of soot occurred at 390 °C in the absence of a catalyst. T50 of CeO2-Al2O3 catalyzed soot oxidation was 296 °C. Adding Zr to the catalyst significantly improved catalytic activity for diesel soot oxidation. We observed a further drastic change in T50 of soot over 1, 3, and 5% Zr/CeO2-Al2O3, which were 220 °C, 210 °C, and 193 °C, respectively. According to these results, incorporating Zr into the CeO2-Al2O3 catalyst significantly improved the oxidation process of soot.


Subject(s)
Aluminum Oxide , Oxidation-Reduction , Soot , Vehicle Emissions , Zirconium , Catalysis , Zirconium/chemistry , Aluminum Oxide/chemistry , Soot/chemistry , Cerium/chemistry , Gasoline
12.
Sci Rep ; 14(1): 16228, 2024 Jul 14.
Article in English | MEDLINE | ID: mdl-39004667

ABSTRACT

Environmental constraints associated with fossil fuels have driven researchers to find a novel, potential and environmentally benign alternative fuel. Biodiesel, vegetable oil, and alcohol have gained rapid momentum thanks to their renewable nature and comparable energy contents in recent years. Accordingly, a Ternary fuel blend is prepared comprising three fuels namely diesel, biodiesel, and pentanol. Waste cooking oil was identified as the source for biodiesel and Pentanol was chosen among various alcohol alternatives due to improved energy density, reduced toxicity. These are endorsed to the enhancement in surface area-volume ratio of nano additives which boosts the catalytic combustion activity and also causing lesser fuel to take part in combustion for maintaining a constant engine speed. The experimentation is done with ternaryfuel blends with varying pentanol and biodiesel concentrations of diesel, biodiesel and pentanol). Upon experimentation, it was observed that, ternary fuel blend 'TF' comprising 70% diesel, 20% biodiesel and 10% pentanol, yielded best performance and was used for doping of Alumina oxide (Al2O3) nano additives. The Al2O3 nanoparticles were doped with ternary blends at fractions of 10 ppm, 20 ppm, and 30 ppm. It was observed that 20 ppm Al2O3 nanoparticle blended TF blend improved BTE and lowered BSFC by about 12.01% and 22.57% respectively. The performance tremendously along with lowered the CO emission by 49.21%, HC emission by 18.91% and smoke opacity by 9.02%.

13.
Materials (Basel) ; 17(13)2024 Jun 22.
Article in English | MEDLINE | ID: mdl-38998159

ABSTRACT

Diesel engines in heavy-duty vehicles are predicted to maintain a stable presence in the future due to the difficulty of electrifying heavy trucks, mine equipment, and railway cars. This trend encourages the effort to develop new aluminum alloy systems with improved performance at diesel engine conditions of elevated temperature and stress combinations to reduce vehicle weight and, consequently, CO2 emissions. Aluminum alloys need to provide adequate creep resistance at ~300 °C and room-temperature tensile properties better than the current commercial aluminum alloys used for powertrain applications. The studies for improving creep resistance for aluminum casting alloys indicate that their high-temperature stability depends on the formation of high-density uniform dispersoids with low solid solubility and low diffusivity in aluminum. This review summarizes three generations of diesel engine aluminum alloys and focuses on recent work on the third-generation dispersoid-strengthened alloys. Additionally, new trends in developing creep resistance through the development of alloy systems other than Al-Si-based alloys, the optimization of manufacturing processes, and the use of thermal barrier coatings and composites are discussed. New progress on concepts regarding the thermal stability of rapidly solidified and nano-structured alloys and on creep-resistant alloy design via machine learning-based algorithms is also presented.

14.
Article in English | MEDLINE | ID: mdl-39052111

ABSTRACT

Glycine max oil biofuel (GMOB) is a product of the transesterification of soybean oil. It contains a substantial amount of thermal energy. In this study, the result of varying fuel injection timings on the performance, ignition, and exhaust parameters of a research engine with single-cylinder, four-stroke with direct injection (DI) diesel was experimentally investigated and optimised using artificial neural networks (ANN). The results demonstrated that a 20% fuel blend with 24.5° before top dead centre (b TDC) decreased brake thermal efficiency (BTE), NOx emissions, and exhaust cylinder temperature but improved fuel consumption, carbon dioxide emissions (CDE), and smoke emissions. With 26.5° b TDC, the BTE was found to be approximately 5.0% higher while the fuel consumption was approximately 2.0% lower than with the original injection timing of 24.5° b TDC. At 26.5° b TDC, the NOx emission was approximately 8.6% higher, and the smoke emission was approximately 4.07% lower than at the original injection timing (24.5° b TDC).

15.
Sci Total Environ ; 946: 174096, 2024 Oct 10.
Article in English | MEDLINE | ID: mdl-38906287

ABSTRACT

Due to environmental pollution and energy crises, zero­carbon fuel ammonia (NH3) has attracted extensive attention as an alternative fuel for engines. In this paper, the effects of ammonia energy ratio (AER) and injection strategy on particulate emission characteristics of an ammonia diesel dual-fuel engine were examined by merging experimental and simulation results; additionally, soot formation and oxidation mechanism were investigated. Results showed that the reduction in particulate emission was substantially higher than the increase in AER. When AER increased to 60 %, the reduction in particulate mass concentration reached 97.5 %. The initial soot formation area gradually moved to the bottom of the piston bowl with increasing AER. When the piston reached the top dead center, the high-soot-concentration area was shifted to the center of the piston bowl as AER increased. The contents of acetylene (C2H2) and methyl (CH3) reduced considerably, which restricted the formation of soot precursors. With AER increasing, the contents of nitric oxides (NOx) and other nitrogen-containing species increased and reacted with CH3 and other carbon-containing species, which effectively reduced the number of C in soot formation pathway, thereby lowering particulate emissions. As AER increased, hydroxyl (OH) involved in soot formation gradually decreased, and only 14 % of OH was involved in the oxidation of n-heptane at 60 % AER, which was favorable for reducing the soot formation rate. Furthermore, OH is a substantial species in soot oxidation. The introduction of ammonia caused an increase in OH, which facilitated the removal of soot. The decrease in hydrogenium (H) hindered the hydrogen-abstraction-acetylene-addition (HACA) reaction, further limiting the soot surface growth. By optimizing the injection timing and AER, particulate emission was lowered to 4.31 × 10-5 µg/cm3, and particle size was reduced by 64.2 % when AER was 60 %, injection timing was -20° CA ATDC, and injection pressure was 60 MPa.

16.
Ecotoxicol Environ Saf ; 278: 116403, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38710145

ABSTRACT

RATIONALE: Diesel engine exhaust (DEE) is associated with the development and exacerbation of asthma. Studies have shown that DEE can aggravate allergen-induced eosinophilic inflammation in lung. However, it remains not clear that whether DEE alone could initiate non-allergic eosinophilic inflammation and airway hyperresponsiveness (AHR) through innate lymphoid cells (ILCs) pathway. OBJECTIVE: This study aims to investigate the airway inflammation and hyperresponsiveness and its relationship with ILC after DEE exposure. METHOD: Non-sensitized BALB/c mice were exposed in the chamber of diesel exhaust or filtered air for 2, 4, and 6 weeks (4 h/day, 6 days/week). Anti-CD4 mAb or anti-Thy1.2 mAb was administered by intraperitoneal injection to inhibit CD4+T or ILCs respectively. AHR、airway inflammation and ILCs were assessed. RESULT: DEE exposure induced significantly elevated level of neutrophils, eosinophils, collagen content at 4, 6 weeks. Importantly, the airway AHR was only significant in the 4weeks-DEE exposure group. No difference of the functional proportions of Th2 cells was found between exposure group and control group. The proportions of IL-5+ILC2, IL-17+ILC significantly increased in 2, 4weeks-DEE exposure group. After depletion of CD4+T cells, both the proportion of IL-5+ILC2 and IL-17A ILCs was higher in the 4weeks-DEE exposure group which induced AHR, neutrophilic and eosinophilic inflammation accompanied by the IL-5, IL-17A levels. CONCLUSION: Diesel engine exhaust alone can imitate asthmatic characteristics in mice model. Lung-resident ILCs are one of the major effectors cells responsible for a mixed Th2/Th17 response and AHR.


Subject(s)
Air Pollutants , Lymphocytes , Mice, Inbred BALB C , Vehicle Emissions , Animals , Vehicle Emissions/toxicity , Mice , Lymphocytes/drug effects , Lymphocytes/immunology , Air Pollutants/toxicity , Inflammation/chemically induced , Eosinophils/immunology , Eosinophils/drug effects , Respiratory Hypersensitivity/immunology , Respiratory Hypersensitivity/chemically induced , Female , Bronchoalveolar Lavage Fluid/cytology , Bronchoalveolar Lavage Fluid/immunology , Male
17.
Sensors (Basel) ; 24(9)2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38732814

ABSTRACT

Fault diagnosis can improve the safety and reliability of diesel engines. An end-to-end method based on a multi-attention convolutional neural network (MACNN) is proposed for accurate and efficient diesel engine fault diagnosis. By optimizing the arrangement and kernel size of the channel and spatial attention modules, the feature extraction capability is improved, and an improved convolutional block attention module (ICBAM) is obtained. Vibration signal features are acquired using a feature extraction model alternating between the convolutional neural network (CNN) and ICBAM. The feature map is recombined to reconstruct the sequence order information. Next, the self-attention mechanism (SAM) is applied to learn the recombined sequence features directly. A Swish activation function is introduced to solve "Dead ReLU" and improve the accuracy. A dynamic learning rate curve is designed to improve the convergence ability of the model. The diesel engine fault simulation experiment is carried out to simulate three kinds of fault types (abnormal valve clearance, abnormal rail pressure, and insufficient fuel supply), and each kind of fault varies in different degrees. The comparison results show that the accuracy of MACNN on the eight-class fault dataset at different speeds is more than 97%. The testing time of the MACNN is much less than the machine running time (for one work cycle). Therefore, the proposed end-to-end fault diagnosis method has a good application prospect.

18.
Sensors (Basel) ; 24(8)2024 Apr 11.
Article in English | MEDLINE | ID: mdl-38676076

ABSTRACT

Due to a rising importance of the reduction of pollutant, produced by conventional energy technologies, the knowledge of pollutant forming processes during a combustion is of great interest. In this study the in-cylinder temperature, of a near series diesel engine, is examined with a minimal invasive emission spectroscopy sensor. The soot, nearly a black body radiator, emits light, which is spectrally detected and evaluated with a modified function of Planck's law. The results show a good correlation between the determined temperatures and the NOx concentration, measured in the exhaust gas of the engine, during a variety of engine operating points. A standard deviation between 25 K and 49 K was obtained for the in-cylinder temperature measurements.

19.
Environ Sci Pollut Res Int ; 31(22): 32449-32463, 2024 May.
Article in English | MEDLINE | ID: mdl-38652187

ABSTRACT

This article presents the outcomes of a research study focused on optimizing the performance of soybean biofuel blends derived from soybean seeds specifically for urban medium-duty commercial vehicles. The study took into consideration elements such as production capacity, economics and assumed engine characteristics. For the purpose of predicting performance, combustion and emission characteristics, an artificial intelligence approach that has been trained using experimental data is used. At full load, the brake thermal efficiency (BTE) dropped as engine speed increased for biofuel and diesel fuel mixes, but brake-specific fuel consumption (BSFC) increased. The BSFC increased by 11.9% when diesel compared to using biofuel with diesel blends. The mixes cut both maximum cylinder pressure and NO x emissions. The biofuel-diesel fuel proved more successful, with maximum reduction of 9.8% and 22.2 at rpm, respectively. The biofuel and diesel blend significantly improved carbon dioxide ( CO 2 ) and smoke emissions. The biofuel blends offer significant advantages by decreeing exhaust pollutants and enhancing engine performance.


Subject(s)
Artificial Intelligence , Biofuels , Glycine max , Vehicle Emissions , Vehicle Emissions/analysis , India , Gasoline
20.
Sci Total Environ ; 927: 172136, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38569946

ABSTRACT

To achieve the collaborative elimination of N2O and carbon of potent greenhouse pollutants from automotive mobile sources, a chemical kinetic model is developed to accurately track the heterogeneous process of carbon-catalyzed N2O reduction based on density functional theory, with experimental data used to validate the model's reliability. The influence of carbon structure, site density, and surface chemical properties on N2O catalytic reduction can be analyzed within this system. Results reveal that the free-edge site of carbon accurately describes the catalytic reduction process of N2O. Adsorption of N2O to carbon edges in O-down, N-down, or parallel orientations exhibits an exothermic process with energy barriers. The N2O with O-down reduction pathway predominates due to the limitations imposed by the unitary carbon site. As the number of active carbon atoms at carbon edges increases, the N2O reaction mode tends towards parallel and N-down pathways, resulting in a significant enhancement of N2O conversion rates and a reduction in catalytic temperatures, with the lowest achievable temperature being 300 K. Furthermore, the triplet carbon structure exhibits higher efficiency in N2O catalytic reduction compared to the singlet carbon structure, achieving a remarkable N2O conversion rate of 93.8 % within the typical temperature exhaust window of diesel engines. This study supplies a breakthrough for carbon materials as catalysts for achieving high N2O conversion rates at low cost, which is important for the collaborative catalytic elimination of N2O and carbon black pollutants.

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