Split Injection Research Articles

Confirmation of Solid Phase Extracted Post‐Blast Explosives Residues Analyzed Using Pulsed Split Injection GC/MS

AbstractA pulsed split injection method was developed for the improved detection of explosives using gas chromatography with mass spectrometric detection (GC/MS) with negative chemical ionization for 12 organic explosives (nitramines, nitrate esters, nitroalkanes, nitroaromatics) and electron ionization with selected ion monitoring for triacetone triperoxide (TATP). An order of magnitude increase in signal (average factor of 13) was observed for all organic explosives with the utilization of the pulsed split injection for samples processed by solid phase extraction (SPE). The method was successfully applied to post‐blast explosives residue processed by SPE and syringe filtration as a confirmatory technique following gas chromatography with electron capture detection (GC/ECD) screening. Compared to current methodologies previously reported, a decrease in the false screen rate (the number of compounds that passed the screening criteria, but not confirmed present) was achieved when employing this method. Processing of post‐blast explosives samples using SPE decreased the false screen rate from 60% to 34%, while using syringe filtration decreased the false screen rate from 73% to 51%.

A-316 A quantitative gas chromatography tandem mass spectrometry method for metabolic profiling of urine organic acids and acylglycines

Abstract Background The analysis of urine organic acids (UOA) and acylglycines (UAG) are an essential investigation for the diagnosis inborn errors of metabolism (IEMs). The vast majority of methods for these analytes use gas chromatography mass spectrometry (GC-MS) and are only qualitative. Gas chromatography tandem mass spectrometry (GC-MS/MS) offers greater sensitivity and selectivity and enables the combination of qualitative screening with quantitative analysis. We describe the development and validation results of a quantitative GC-MS/MS method. Methods Urine creatinine concentrations were measured (CobasPro, Roche Diagnostics) and normalized to 1.25 mmol/L. After internal standard addition, each urine specimen, calibration standard and QC were incubated with a hydroxylamine solution followed by a liquid-liquid extraction. Further sample concentration permitted the isolated UOA and UAG to be derivatized using N,O-bis(trimethylsilyl)trifluoroacetamine (BSTFA) with 1% chlorotrimethylsilane (TMCS) prior to injection. GC-MS/MS analysis was performed using a GC-MS-TQ8050 triple quadrupole system (Shimadzu) with a 30 m DB-5MS (Agilent J&W) capillary column (0.25 mm, ID of 0.25 µm). Split injection mode was deployed with an initial column temperature of 70°C. The mass spectrometer was operated in electron ionization (EI) and multiple reaction monitoring (MRM) modes. Results The optimal temperature gradient for high-resolution UOA and UAG separations was derived and their respective retention times determined. MS/MS detection parameters were optimized to permit the identification of precursor and production ions for all (N=36) derivatized analytes. Total analysis time was 33.8 min per injection. This method permits the measurement of 11 samples in one batch and is highly linear for all analytes (R^2 >0.99 and average slope 1.04). The limit of quantification (LOQ) was established and ranged from <0.05 to 2.1 µmol/mmol creatinine. Intra- and inter-day imprecision (CV%) was determined using matrix-matched abnormal and normal QC. Intra-day imprecision (N=10) ranged from 1.3% (2-ketoglutaric acid) to 9.7% (3-hydroxybutyric acid). Inter-day imprecision (N=30 over 15 days) ranged from 2.2% (ethylmalonic acid and methylmalonic acid) to 20.5% (3-hydroxy-3-methylglutaric acid). The method had an average accuracy of 113±14% for analytes included in the ERNDiM quantitative organic acids (urine) external quality assurance program. For analytes not included in this proficiency testing, the method showed good agreement when compared to a national reference laboratory, with average Deming correlation coefficients and regression slopes being 0.9944 and 1.1, respectively. No interferences were detected when monitoring the analyte quantifier and qualifier ion ratios in patient urine. Conclusions The devised GC-MS/MS protocol permits the unbiased identification and quantification of UOA and UAG used to investigate IEMs. The method has acceptable sensitivity, specificity, precision and accuracy for clinical routine clinical testing.

Numerical and Optimization Studies on Reactivity Controlled Compression Ignition Engine with Hydrogen and Split Injections

Abstract Effective abatement of harmful tail-pipe emissions from fossil fuel run engines is achieved through low-temperature combustion strategies; Reactivity Controlled Compression Ignition mode of operation has been successful among such concepts. The present work deals with numerical work performed using ANSYS Forte software with n-heptane as a high-reactivity fuel and hydrogen in different proportions as a low-reactivity fuel, respectively. With total energy fixed, the amount of hydrogen is varied from 0-80% fuel injection is regulated accordingly. Pertinent engine in-cylinder parameters with patterns are extracted, emphasizing the combustion phenomena of RCCI operation with the lowest possible emissions targeted, with the combined effects of hydrogen induction, Start of Injection, and split injections. The contours of fuel vapour and emission parameters are obtained to relate the performance with emissions. It is noted that with a split injection strategy at 50/50 and 75/25 split strategy and 45-50% energy share from hydrogen, the NOx, Soot reductions and thermal efficiency penalty are in the range of about 5.5%, 24% and 7.5%, respectively, also, with 30% EGR, about 95% NOx reduction but with higher soot values. A 75/25 split and advanced injection timing of 25obTDC resulted in the RCCI mode of operation with reduced soot emissions, and the use of EGR has resulted in high levels of soot and poor fuel efficiency. Among the models of machine learning tested, Random Forest regressor emerged as the most suitable, with higher R2 values, indicating better predictive capability.

Experimental multiple parameters optimization of the injection strategies for a turbocharged direct injection hydrogen engine to achieve highly efficient and clean performance

Improving the brake thermal efficiency (BTE) and reducing NOx emissions are two main goals for hydrogen-powered internal combustion engines to achieve efficient and clean performance. This paper focuses on the multiple parameters optimization of injection and ignition both experimentally and numerically based on a 2.0L turbocharged direct injection hydrogen engine. Firstly, the effects of single and split injection on engine performance, in-cylinder mixing and combustion characteristics are investigated. Secondly, the single-factor effect of split injection parameters and spark timing on engine performance are obtained with different engine speeds. Significant interaction effects are detected between these factors. Thus, a multi-parameter optimization is conducted based on the response surface methodology method to analyze the co-relationship of factors (split injection control parameters and ignition) on responses (BTE, NOx emissions, and knock intensity) at high-load. Finally, a maximum BTE of 43.03% and a reduction in NOx emissions by 71.19% are achieved with the help of model prediction at 2500 rpm and a load of 1.40MPa. Further optimization of other engine speeds is conducted, and the boundary of high-efficiency region (BTE>40%) covers over 50% of the load map after optimization. These results can provide valuable support for the performance improvement of efficiency and clean hydrogen engines.

Development and Application of Integrated Injection System for Injection and Profile Control in Dagang Oilfield

Abstract Dagang Oilfield is a heterogeneous, multi-layered, and structurally complex fault block oil reservoir. During the production process, the contradictions between layers and within layers are becoming increasingly prominent. Split injection and profile control are two important development processes for ensuring production and increasing production in current oilfield development. However, during the construction process of split injection wells for profile control, there are often problems with plugging agents, which affect the effectiveness of split injection and the success rate of testing and adjustment, and even require well repair operations. This has become a key quality control production link that affects the efficiency of oil recovery construction and the improvement of quality, cost, and efficiency. The idea of developing a new type of integrated water distributor for injection and profile control has been proposed, which can achieve dual functions of layered water injection and profile control using a set of pipe columns. Through several years of technological breakthroughs, technological breakthroughs have been made in various aspects such as main structure design, anti backflow structure design, and water nozzle optimization design. Innovative proposals have been made and the integrated water distribution device structure design for injection and profile control has been successfully developed, fundamentally solving the pain points and difficulties of low measurement and adjustment rate after injection well profile control construction, significantly improving the qualification rate of measurement and adjustment, and significantly improving work efficiency and construction quality.

Computational investigation of a methanol compression ignition engine assisted by a glow plug

This work explores the feasibility of pure methanol combustion in a light-duty diesel engine assisted by a glow plug (GP). The simulations represented a mild engine load with an indicated mean effective pressure of 7 bar. An extensive computational study was conducted, and the successful operation of the pure methanol compression ignition engine was demonstrated. The effects of the GP position, spray umbrella angle, the relative angle (RA) between the glow plug and jet trajectory, and the injection strategy on the engine performance were evaluated. The autoignition of methanol-air mixture was found to primarily occur at an equivalence ratio between 0.2 and 0.4. However, an even richer mixture accompanied the lower temperature due to intense heat absorption of evaporation, significantly prolonging the ignition delay. Therefore, to improve the ignition and combustion heat release processes, RA was optimized to adequately control the mixture distribution around the GP. At each position of the GP, the optimum RA differed due to the complex flow and air-fuel mixing within the combustion chamber, which became smaller (from 12.5° to 5°) when the GP was moved anticlockwise from the intake port to the exhaust port regions. Furthermore, a split injection strategy was proposed to ensure the successful ignition of the methanol jets. The engine performance exhibited a high sensitivity to the pilot and main injection timings. A small pilot mass fraction of no higher than 20% was recommended to mitigate fuel jet-GP interaction and fuel impingement in the squish region.

Investigation of low carbon emission and high thermal efficiency of diesel engine combined with high-pressure direct injection of hydrogen carrier: Ammonia

Ammonia, as a zero-carbon fuel, has the potential to serve as a medium for the production, transportation, and utilization of clean energy. The scaling up of green ammonia production also necessitates broader utilization channels for ammonia. Applying ammonia as a fuel in engines is an effective way to reduce carbon emissions. This paper employs dual direct injection technology of ammonia and diesel in a novel ammonia-fueled engine to implement various control strategies and investigates their effects on combustion and emission performance. The results indicate that when the ammonia injection timing is advanced from −40°CA ATDC to −60°CA ATDC, the flash boiling of liquid ammonia decreases the indicated thermal efficiency (ITE) below 39% and increases unburned gas emissions. Globally, injecting ammonia during the intake stroke could receive better performance. Split injection strategies of diesel significantly improve the ITE, especially under a higher pilot-injection ratio of 75%. Additionally, increasing the load benefits the ammonia combustion process. Raising the IMEP to 12 bar improves ammonia combustion efficiency to over 95%, with an ITE reaching 49%.

Enhancing energy and nitrogen removal efficiency through automatic split injection and innovative aeration device: A study of low C/N ratio environments

A new aeration device based on Bernoulli's principle, Jetventrumixer (JVM), was introduced into an aeration tank in denitrification process, which involved an automatic split injection system (ASIS) into two denitrification tanks every 10 minutes. Real-time monitoring of influent water allowed the calculation of the C/N ratio, enhancing the utilization efficiency of internal carbon sources while reducing the need for external carbon. The comparison of the JVM with the conventional air diffuser for 100 days operation showed that the removal efficiency for NH4+-N in both systems was approximately 98 %, but the nitrification efficiencies were 84 % and 80 %, respectively. This indicates that the JVM achieves an high enough removal efficiency and nitrification efficiency compared with conventional air diffuser system with dramatic reduction in energy consumption by 52.1 %. When the influent wastewater was split and injected into duplicate denitrification tanks at ratios of 3:7, 5:5, and 7:3, the total nitrogen (TN) removal efficiencies were 77 %, 73 %, and 72 %, respectively. In contrast, with the implementation of the ASIS, the TN removal efficiency increased up to 82 %. The increase in TN removal indicates that real-time monitoring could stably track changes chemical composition in wastewater influent over 24 h and introducing ASIS facilitate the efficient utilization of internal carbon sources, thereby enhancing denitrification efficiency and improving TN removal efficiency. Finally, the greenhouse gas (GHG) emissions from the JVM and air diffuser were 9.39401 and 19.60488 tCO2eq year-1, respectively, representing a 52% reduction. Therefore, JVM and ASIS successfully reduced energy consumption and enhanced both nitrification and denitrification efficiencies.

Enhancing the usability range of acetylene in CI engines through split injection of high-reactive fuel under RCCI operation: Optimized operability using an MCDM approach

Reactivity Controlled Compression Ignition (RCCI) has emerged as a promising solution to address the challenges of advanced combustion techniques in diesel engines, balancing combustion control and emission reduction. This study investigates the impact of split-injection high-reactivity fuel (HRF) dosing in RCCI to enhance charge homogeneity at lower injection timing advancements. It systematically explores progressive advancements in HRF injection timing, distinguishing between main and pilot injections. The main injection varied from 20° bTDC to 70° bTDC, while the pilot injection, relative to the main injection, spans 25°-40° CA ahead with a 5° progression. As an LRF, Port-injected Acetylene supplements the process with variable premixed ratios. Further, using a multi-criteria decision-making method (AHP), the study optimizes operating conditions, proposing a main injection at 20° bTDC, a pilot injection 40° CA ahead, and 70 % LRF participation. This optimized condition yields significant benefits such as 32.99 % higher brake thermal efficiency (BTE), 160 % longer premixed duration, 18.65 % lower maximum temperature, 89.41 % lower NO emissions, 91.83 % lower hydrocarbon (HC) emissions, 91.24 % lower CO emissions and 97.20 % lower smoke opacity compared to conventional diesel combustion (CDC) operation. The results highlight the advantages of multiple fuel injections in RCCI, improving blending characteristics at lower injection angles.

Co-optimization and prediction of high-efficiency combustion and zero-carbon emission at part load in the hydrogen direct injection engine based on VVT, split injection and ANN

Hydrogen fuel holds great promise for accelerating the energy sector's decarbonization efforts. However, hydrogen's unique properties pose challenges for hydrogen direct injection (HDI) engines, such as differences in airflow exchange capabilities for very low density and reduced combustion rates due to lean burn conditions. This study investigates the impact of combined variable valve timing (VVT) and split injection strategies on HDI engine combustion, efficiency, and emissions. Using Artificial Neural Network (ANN) models and experimental data, predictive models for Brake Thermal Efficiency (BTE) and Nitrogen Oxide (NOx) emissions were developed. Adjusting intake and exhaust valve timings improved BTE by up to 2.5 % and 1.8 %, respectively, while reducing NOx emissions by 48.9 % and 31.1 % under specific conditions. Optimizing split injection alongside VVT further increased BTE by 1.2 % and 0.9 %, but increased NOx emissions by 29.9 % and 26.5 %. The flexible application of VVT and split injection strategies aims to balance efficiency gains with emissions control. The ANN-based models demonstrated high accuracy (R2 > 0.974), proving reliable substitutes for real-engine testing in certain conditions. In conclusion, this research highlights the potential of VVT and split injection strategies to enhance HDI engine performance while mitigating environmental impact, supporting the transition to sustainable energy solutions.

Effects of diesel injector nozzle angle and split diesel injection strategy on combustion and emission characteristics of an ammonia/diesel dual-fuel engine

Pre-injection can effectively improve combustion and thermal efficiency while reducing unburned ammonia (uNH3) and N2O emissions in ammonia/diesel dual-fuel engines. Nevertheless, the pre-injected diesel often impacts the cylinder liner or piston pinch area, adversely affecting combustion and emissions. In this study, various narrow injector nozzle angles (90°/60°) of diesel fuel are applied on investigating engine performance and emissions. Experiments are conducted at 1200 r/min, IMEP 1.2 MPa, and AEF (ammonia energy fraction) 50 %, consisting of varying INA (injector nozzle angle) of 145°/90°/60°, PIR (pre-injection ratio) from 20 %–80 %, PIT (pre-injection timing) from −70 °CA ATDC to −30 °CA ATDC, and sweeping MIT (main injection timing). Results show that larger INA prefer a lower PIR and delayed PIT to reduce the pre-injected fuel hitting the liner, and smaller INA prefer a higher PIR to reduce the main-injected fuel hitting the piston wall. ITE of INA145° peaks at a moderate PIR and delayed PIT while ITE of INA90° and INA60° peaks at a high PIR and early PIT. Decreasing INA combined with high PIR and early PIT helps to reduce uNH3, N2O, and GHG emissions, at the cost of a slight decrease in ITE.

Effect of injection strategy on the hydrogen mixture distribution and combustion of the hydrogen-fueled engine with passive pre-chamber ignition under lean burn condition

Turbulent jet ignition (TJI) effectively achieves lean and stable combustion in hydrogen engines. However, research on injection strategies for TJI hydrogen engines is still lacking. In this study, experimental methods investigated the effects of single and split injection strategies on the combustion and emissions of TJI hydrogen engines under medium loads. The numerical simulation reveals the operational characteristics of fuel distribution, ignition capability, and energy conversion in the pre-chamber at different injection times in a single injection strategy. This work is conducted at 1600 rpm with a manifold absolute pressure of 70 kPa. The experimental results indicate that the delay of the start of injection (SOI) can enhance the performance of the TJI hydrogen engine. However, as SOI approaches TDC, emissions worsen, and combustion stability decreases. When SOI is 90°CA BTDC, the brake mean effective pressure (BMEP) and brake thermal efficiency (BTE) can achieve 3.1 bar and 32.9 %, with the coefficient of variation of the IMEP (COVIMEP) of 1.6 % and lower emissions. For the split injection strategy, delaying the secondary end of injection (SEOI) can increase BMEP and BTE. As SEOI gradually delays the TDC, emissions deteriorate sharply. Under the split injection strategy, COVIMEP is higher, which is unfavorable for hydrogen engine applications.

Effects of dual injection operations on combustion performances and particulate matter emissions in a spark ignition engine fuelled with second-generation biogasoline

The automotive industry must mitigate climate change by reducing vehicle carbon emissions and promoting sustainable transportation through technical solutions and innovations. Biofuels are seen as a solution to reduce CO2 emissions, but they may affect fuel performance and emissions. Second-generation biogasoline mixed with ethanol has proven that it can be introduced as a drop-in fuel with the same performance and tailpipe emissions at the same level as fossil fuels. However, particulate matter (PM) emissions are significantly higher than fossil fuels. This study aims to experimentally investigate the effect of port and direct fuel injections on the PM emissions in a boosted spark ignition (SI) engine fuelled by Euro 6 standard biofuel with a 99 octane number blended with 20% ethanol compared to a fossil fuel baseline. The single-cylinder SI engine was equipped with two fuel injectors, a direct injector and a port fuel injector, and operated with externally boosted air. The split injection ratio was adjusted from 100% direct injection (DI) to 100% port fuel injection (PFI) to investigate the combustion characteristics and particulate emissions (PM) at different engine loads and speeds. The results indicate that by changing 100% DI to 80% PFI, PM emissions numbers between particle sizes of 23 and 1000 nm were dropped by 96.56% at a low load operation of 4.6 bar IMEP for the 99 RON E20 biogasoline and by 84% for the 95 RON E10 fossil fuel while maintaining the same indicated thermal efficiency and a similar level of other emissions. However, at a higher load above 10 bar IMEP, it was found that full DI operation reduced particulate numbers (PN) by 64% and 38% for 99 RON E20 biogasoline and 95 RON E10 fossil fuel at 20 bar IMEP, respectively, and enabled more stable operation at 3000 rpm with higher load operation regions.

Split injection timing optimization in ammonia/biodiesel powered by RCCI engine

Employing carbon-neutral (NH3) and low carbon footprint (biodiesel) fuels in Reactivity Controlled Compression Ignition (RCCI) engine mode is one possible method for minimizing carbon emissions in diesel engines. In this study, a Compression Ignition (CI) engine was customized to run in RCCI mode, employing High Reactive Fuel (HRF) as biodiesel and Low Reactive Fuel (LRF) as ammonia (NH3). Based on our earlier findings, the proportion of ammonia in premixing is fixed at 40 %. In the first phase, the primary injection timing of the algal biodiesel varied between 12 and 21°CA bTDC at a preset pre-injection timing of 46°CA bTDC. In the next phase, the pre-injection time varied between 46 and 54°CA bTDC, with the optimal main injection time being 18°CA. The result suggested that the optimal main and pre-injection at 18 and 58°CA bTDC increased the Cylinder Pressure (CP) by 30.1 %, and peak HRR and combustion phase angle were advanced. Brake Thermal Efficiency exhibited an 11 % enhancement, with Brake Specific Energy Consumption decreasing by 24.1 %. Nitrogen Oxide levels saw an increase of around 39.5 %. In contrast, reductions of 19.2 %, 23.5 %, 39.7 %, and 21.7 % were observed in Hydrocarbons, Carbon Monoxide, smoke emissions, and Exhaust Gas Temperature, respectively, compared to the single injection under full load conditions.

Effect of injection timings and injection pressure on knock mitigation with a compression stroke injection of hydrous ethanol in spark ignition

Direct injection fuel systems provide precise control over the amount of fuel injected and can enable higher compression ratio operation and earlier combustion phasing under knock-limited operation, particularly for fuels with a high cooling potential like hydrous ethanol, a blend of 92% ethanol and 8% water. Moving a portion of the total fuel mass from an intake stroke injection to a compression stroke injection can provide a knock suppression benefit, which can enable more efficient operation. In this work, the influence of injection pressure on this split injection spark ignition strategy is examined. The effect of injection pressure on two intake stroke injections were characterized, with an injection pressure of 200 bar improving combustion efficiency by ∼3 percentage points and advancing knock-limited CA50 by 1 crank angle degree over an injection pressure of 30 bar. Then, a compression stroke injection was introduced and swept into the compression stroke while maintaining the two intake stroke injections. Direct injections at an injection pressure of 30 bar enabled a small knock intensity reduction of ∼20%, whereas an injection pressure of 200 bar enabled a larger reduction of ∼90% in knock intensity. The spark timing advance permitted by the reduction in knock intensity with a compression stroke injection timing of −80 degrees after top dead center was 0.3 and 2.0 degrees at an injection pressure of 30 and 200 bar, respectively. Then, the second intake stroke injection was varied at 200 bar to evaluate how the stratification profile prior to the compression stroke injection impacted its ability to reduce knock intensity. It was found that compression stroke injections with an early second intake stroke injection was effective at reducing knock intensity throughout the compression stroke. As the second intake stroke injection was retarded, the early compression stroke injections became less effective at suppressing knock.

Experiments and modeling of the thermal spray-chasing phenomenon during split injection processes

Spray chasing is a specific manifestation of the interaction between split injections, where the mass and heat transfer between the pilot and main sprays significantly influence fuel mixing and ignition processes. In this study, a spray-chasing model is developed and validated based on optical diagnostic results, aiming to theoretically support the development of injection strategies that are more environmentally adaptive and offer improved performance. A series of optical diagnoses of diesel split injection is performed in a constant volume combustion chamber using diffused back-illumination imaging and high-speed schlieren imaging. The extent of the spray-chasing phenomenon is modulated by regulating the injection dwell time (DT) and ambient temperature. For inert sprays, when the background temperature exceeds 790 K, the liquid spray-chasing phenomenon can be disregarded owing to the premature evaporation of the pilot spray. Although shortening the DT can promote the development and mixing of the main spray, the lack of evaporation in the pilot fuel pocket leads to a higher local fuel concentration in the interaction zone after spray chasing, which will hinder the subsequent ignition of the main spray. For reactive sprays, the variations in spray chasing patterns under different operating parameters are determined and their impact on the ignition process is evaluated by combining optical test results with theoretical models. Under cold start conditions, the ignition delay and ignition location of the main spray exhibit a non-monotonic trend with increasing injection dwell time. Optical diagnosis observes that compared to DT of 200 us and 1500 μs, the main spray exhibits both valley in ignition delay time and ignition location at DT = 900 μs. The spray-chasing model identifies approximately 1020 μs as the optimal theoretical DT, expected to best facilitate ignition of the main spray. However, under hot-start conditions, even though the spray-chasing mode varies with different injection dwell times, the ignition characteristics remain essentially unchanged due to the limited promotion effect of split injection on ignition.

Investigation of Split Diesel Injections in Methanol/Diesel Dual-Fuel Combustion in an Optical Engine

Methanol is a promising alternative fuel due to its wide availability of raw materials, mature production processes, and low production cost. However, because of the low cetane number, methanol must include a more reactive fuel to assist with combustion when used in compression ignition (CI) engines. In this study, based on the optical CI engine platform, methanol is injected into the intake port, and diesel is directly injected into the cylinder to achieve dual-fuel combustion. The effects of the methanol energy ratios and diesel split injection strategies on combustion are investigated. The results show that the premixed blue flame was mainly concentrated in the near wall region, whereas the yellow flame produced by diesel combustion tended to concentrate in the central region as the methanol energy ratio increased. When the methanol energy ratio exceeded 50%, the ignition delay was significantly prolonged, while the flame area was greatly reduced. Meanwhile, the peak values for the cylinder pressure and heat release rate decreased significantly, indicating a significant deterioration in combustion. At the earlier diesel pre-injection timing at −58°, the overall dual-fuel combustion at each main injection timing exhibited low-temperature premixed combustion characteristics, with a lower peak exothermic rate and flame brightness. At the later pre-injection timing at −33°, the spray flame at all main injection timings could be observed, with higher peak heat release rates and indications of thermal efficiency. Combustion at later main injection timings was characterized by diffusion combustion, and the main injection timing could effectively regulate the combustion process through phase adjustment.

Microscopic spray characteristics of diethyl ether–diesel blends under single and split injection strategies

The phase doppler interferometry technique was used to thoroughly investigate microscopic spray characteristics of single and split injection strategies. The diethyl ether blending with diesel resulted in smaller and uniform droplet formation. Diethyl ether–diesel blend spray exhibited a lower droplet axial velocity distribution than baseline diesel, which can be improved by split injection strategies. At atmospheric pressure, the maximum axial velocity for diesel and diethyl ether–diesel blends was almost identical under single and split injection strategies. However, split injection improved the spray droplet's axial velocity at higher ambient pressures compared to single injection. The chances of coalescence and having coarse droplets were higher at elevated ambient pressure, especially for lower fuel injection pressures. Therefore, increasing the fuel injection pressure is more suitable to avoid droplet coalescence. Unlike the split ratio, dwell time strongly influenced fuel spray atomization. The droplet diameter distribution exhibited a higher probability of finer droplets for a longer dwell time of 0.45 ms than a shorter dwell time of 0.15 ms. A major finding of this study is that diethyl ether–diesel blend spray with a longer dwell time exhibited superior spray characteristics.

Enhancing Combustion Stability in Biodiesel Engines: The Plausibility of n-Butanol Injection Phasing and Reactivity-Controlled Compression Ignition–An Experimental Endeavour

This study explores the synergistic effect of injection phasing on reactivity-controlled compression ignition strategies upon the combustion and stability indices of biodiesel-fuelled single-cylinder four-stroke diesel engines. Mahua Biodiesel was used as the primary fuel, and n-butanol was injected into the manifold to achieve that strategy. The tests were conducted with varying the start of pilot-main injection timing, energy share of biodiesel in split injection and energy share of butanol. This work also entails the various combustion characteristics and the corresponding consequences on the engine’s performance-emission. Ignition delay is shortened with retarded injection timing. At the same time, combustion duration is reduced with higher butanol share and advanced injection timing of biodiesel. The butanol injection and advanced pilot biodiesel injection timing revealed the advancement of combustion phasing. In conjunction with n-butanol port fuel injection, the current study demonstrates the noteworthy and potential superiority of n-butanol as the less reactive constituent. Shortened ignition delay exhibited improved performance and UHC-CO footprint. This study highlights the maximum reduction in regulated emissions compared to operations solely relying on 100% biodiesel. The occurrence of CA50 at 5°–7° CA revealed a maximum decrease in NOX-UHC-CO-CO2 emissions compared to the B100 fuelled strategy. The reduction percentages observed were 53.4%, 97%, 81.1%, and 53.2%, respectively.

Using CRITIC-TOPSIS and python to examine the effect of 1-Hepatnol on the performance and emission characteristics of CRDI CI engine with split injection

Recently, biofuels with higher alcohol content have become a promising alternative to diesel fuel. These fuels are appealing because they are sustainable, renewable, and possess attractive fuel properties. This study uses a split injection strategy to analyze the performance and emissions of a CRDI diesel engine fueled by 1-heptanol. The work involved testing different fuel blends, ranging from 10 % to 30 %, while maintaining a constant engine speed of 1500 rpm and varying the operating load between 0 kg and 12 kg in 4 kg increments. During the second stage, the CRITIC-TOPSIS method determines the objective weights and rankings of various criteria and alternatives. A Python approach based on machine learning was used to ensure the CRITIC-TOPSIS results were accurate. Seven criteria were evaluated to maximize BTE while minimizing BSFC, NOx, smoke opacity, HC, CO, and CO2. The experimental results showed a slight drop of 2.98 % in BTE and an increase of about 13.33 % in BSFC. NOx and smoke opacity were reduced by 7.13%–4.53 %, while there was a 12.12 % increase in HC, 6.45 % higher CO, and a 5.5 % increase in CO2 at full load. Adding 1-heptanol to diesel and using a split injection strategy significantly reduced NOx and smoke opacity. The final ranking and best blend are determined using CRITIC-TOPSIS and Python algorithms to estimate performance and emissions criteria. At a load of 4 kg, D100 ranks first with a relative closeness value of 0.642, while at a pack of 8 kg, the blend HP20D80 ranks first with a relative closeness value of 0.633. According to the rankings, the HP20D80 blend is the best option for achieving optimal performance and reduced emissions in CRDI diesel engines. A research paper has presented a unique approach to multiple criteria decision-making (MCDM) validated using a Python algorithm. This method can assist decision-makers in making better-informed choices when faced with MCDM problems that involve various criteria and alternatives.