Engine Emission Characteristics Research Articles

Optimizing engine performance and emission properties with Garcinia indica biodiesel: a holistic RSM-TLBO-DFA strategy

Garcinia indica (GI) feedstock poses high oil content (45.2%) and after transesterification resulted with 94.8% yield. The GI crude oil, biodiesel, and their blends were tested for fuel characteristics and run in a diesel engine. Response surface methodology based on central composite design experimental matrices was used to model and examine the input variables (engine load, injection timing, injection pressure, and blend type) on engine performance (brake thermal efficiency (BTE), brake specific fuel consumption (BSFC)) and emission characteristics (nitrogen oxide (NOx), unburnt hydrocarbon (UHC), carbon monoxide (CO)). All factors showed significant effects (except injection pressure and injection time for NOx) on all responses. The empirical equations predicted 27 experimental cases with 4.75% accuracy. Desirability function approach was applied to transform all output functions (maximize BTE and minimize BSFC, CO, NOx, and UHC) with different weight fractions (WF) to single composite desirability function for maximization. Teaching learning-based optimization (TLBO) determined optimal condition corresponding to case 4 (maximum WF to CO, minimum WF to BTE, BSFC, UHC, NOx) resulting in highest desirability function value (0.9432) with a percent deviation of 7.09%. The developed models assist novice users in predicting unknown parametric conditions and improving engine performance and emission characteristics without practical experiments.

Improvement of Engine Combustion and Emission Characteristics by Fuel Property Modulation

The sustainability of diesel engines has come to the forefront of research with the growing global interest in reducing greenhouse gas emissions and improving energy efficiency. The aim of this paper is to support the goal of sustainable development by improving the volatile properties of diesel fuel to promote cleaner combustion in engines. In order to study the effect of diesel fuel volatility on spraying, combustion, and emission, the tests were carried out with the help of the constant volume chamber (CVC) test rig and an engine test rig, respectively. CVC test: A high-speed video camera recorded the spray characteristics of different volatile fuels in a constant-volume combustion bomb. The effects of different rail pressures and ambient back pressures on the spray characteristics were investigated. Engine test: The combustion and emission characteristics of different volatile diesel fuels under different load conditions (25%, 50%, 75%) were investigated in a four-stroke direct-injection diesel engine with the engine speed fixed at 2000 rpm. The test results show that as the rail pressure increases and the ambient pressure decreases, the spray characteristics of the fuels tend to increase; for the more volatile fuels, although reducing the spray tip penetration, the spray projected area and spray cone angle increase, which is conducive to improving the homogeneity of the fuel and air mixing in the cylinder. The improvement of fuel volatility can form more and better-quality mixtures within the ignition delay time (ID), resulting in a 1–2% increase in peak cylinder pressure and a 2–4% increase in peak heat release. For different loads, pre-injection heat release is generated to redefine the ID and combustion duration (CD). Improved fuel volatility effectively reduces carbon monoxide (CO) emissions by about 8–10% and hydrocarbon (HC) emissions by about 13–16%, but it increases nitrogen oxide (NOx) emissions by about 8–11%. Analyzing from the perspective of particulate matter (PM), combined with the aromatic content of volatile fuels, it is recommended to use fuels with moderate volatility and aromatic content under low load conditions, and at medium to large loads, the volatility of the fuel has less weight on particulates and more weight on aromatics, so it is desirable to use the fuel with the lowest volatility and lowest aromatic content of the fuel selected.

A sustainable Response Surface Methodology and Analytic Hierarchy Process - Weighted Aggregated Sum Product Assessment model to Evaluate Performance and Emissions Characteristics of Diesel engine using Clove Oil Biodiesel Blend

Abstract Replacing diesel with biodiesel generally results in a decrease in exhaust emissions like carbon monoxide, hydrocarbon, particulate matter, and carbon dioxide. However, nitrogen oxide emissions show increasing trends. On the other hand, a decrease in nitrogen oxide emissions has been found using various additives with diesel and biodiesel blends. In this work the experimentations are carried out on diesel, B30 (70% v/v diesel+30% v/v biodiesel), and the B30CL1000 (70% v/v diesel+30% v/v biodiesel+1000 ppm clove oil) to evaluate the performance and emissions of diesel engine. The Response Surface Methodology based approach has been applied to evaluate the effect of different engine operating parameters on engine performance and emission while fueled with the B30CL1000 fuel blend. Further, the Analytic Hierarchy Process - Weighted Aggregated Sum Product Assessment method has been applied to identify the optimal setting of the parameters and rank the optimal engine operating range for the B30CL1000 blend. From results, elicited that the accumulation of 1000 ppm of antioxidant (clove oil) additives in the B30 blend resulted in a reduction in the brake-specific fuel consumption by up to 11.5% at higher loads. Brake thermal efficiency increased by 16.3% at low load conditions for the B30CL1000 blend. After that the B30CL1000 blend showed a 2% drop in carbon monoxide emission at higher loads and the decreased nitrogen oxide emission for the B30CL1000 blend has been also reported as 12% at low loads and 2% at higher loads which follows a similar trend as exhaust gas temperature. The 5th experimental run having CR (17), EGR (0%) and Load (12kg) has been ranked as 1.

Numerical investigation and optimization of the ammonia/diesel dual fuel engine combustion under high ammonia substitution ratio

This study investigated the effects of initial temperature, equivalence ratio, and diesel injection timing on engine combustion and emission characteristics at high ammonia substitution ratios. Increased compression temperature and pressure significantly reduce ignition delay, enhance combustion speed and efficiency, and decrease N2O and unburned NH3 emissions. A strong correlation exists between the amount of N2O produced and the mass of unburned NH3 when ammonia combustion efficiency is high. The N2O distribution is concentrated near the cylinder walls and the bottom surface of the piston platform, in areas with high concentrations of unburned NH3. As the equivalence ratio increases from 0.6 to 0.75, flame propagation speed and indicated thermal efficiency (ITE) increase, while NOx, N2O, and unburned NH3 emissions decrease. The combustion performance and emissions were optimized by advancing the diesel injection timing and increasing the equivalence ratio to accelerate the combustion speed. This adjustment increases ITE to 47.6% at an 80% ammonia energy ratio. Post-optimization results show a reduction in unburned NH3 emissions from 51.7 g/kW·h to 5.9 g/kW·h and a decrease in N2O emissions from 0.930 g/kW·h to 0.370 g/kW·h, culminating in a 60.4% reduction in greenhouse gas (GHG) emissions.

Numerical Investigation of Combustion and Emission Characteristics of the Single-Cylinder Diesel Engine Fueled with Diesel-Ammonia Mixture

This study proposes a dual-fuel approach combining diesel and ammonia in a single-cylinder compression ignition engine to reduce harmful emissions from internal combustion. Diesel is directly injected into the combustion chamber, while ammonia is introduced through the intake manifold with intake air. In this study, injection timing and the percentage of ammonia energy fraction was varied. A computational fluid dynamics (CFD) model simulates the combustion and emission processes to assess the impact of varying diesel injection timings and ammonia energy contributions. Findings indicate that as ammonia content increases, the engine experiences reductions in peak in-cylinder pressure, temperature, heat release rate, as well as overall efficiency and power output. Emission results suggest that greater ammonia usage leads to a reduction in soot, carbon monoxide, carbon dioxide, and unburned hydrocarbons, though a slight increase in nitrogen oxides emissions is observed. This analysis supports ammonia’s potential as a low-emission alternative fuel in future compression ignition engines.

Impact of nano cerium oxide addition with pyrolysis waste plastic oil on combustion, performance and emission characteristics of CRDI diesel engine

Abstract This investigation examined the effect of incorporating cerium oxide (CeO2) nanoparticle into diesel and waste plastic oil (WPO) blends on the combustion, performance and emission characteristics of the diesel engine. The WPO was extracted from low density polyethylene using plastic pyrolysis. The blending of diesel and WPO with combination of D70:WPO30 and D50:WPO50 was prepared to evaluate the engine operation. Additionally, the spherical sized CeO2 with 50 mg/L and 100 mg/L was added with this blend. The various blends named as Diesel, D-WPO30, D-WPO30+Ce50, D-WPO30+Ce100, D-WPO50, D-WPO50+Ce50 and D-WPO50+Ce100 were used in this investigation to operate the engine under various load conditions. The experiment was performed using water cooled common rail direct injection (CRDI) diesel engine with prepared D-WPO blend. Different characteristics such as In-cylinder pressure (CP), heat release rate (HRR), ignition delay time (IDT), brake thermal efficiency (BTE), brake specific fuel consumption (BSFC) and exhaust gas temperature (EGT), carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOx) and smoke opacity emission are studied with respect to the effect of different blends and applied load used. It was observed that increasing of CeO2 nanoparticles in blend improved the overall performance and emission of the engine. Form the results, D-WPO30+Ce100 blend showed enhanced brake thermal efficiency (BTE), brake specific fuel consumption (BSFC) and exhaust has temperature (EGT) are 28.2%, 3% and 465oC respectively. Similarly, reduced emission of CO, NOx, HC and smoke opacity was observed in the CeO2 added blends particularly at 100 mg/L. It was concluded that among all blends prepared, the D70:WPO30 with 100 mg/L of CeO2 showed improved combustion, performance and emission characteristics in proposed diesel engine.

Prediction of Efficiency, Performance, and Emissions Based on a Validated Simulation Model in Hydrogen–Gasoline Dual-Fuel Internal Combustion Engines

This study explores the performance and emissions characteristics of a dual-fuel internal combustion engine operating on a blend of hydrogen and gasoline. This research began with a baseline simulation of a conventional gasoline engine, which was subsequently validated through experimental testing on an AVL testbed. The simulation results closely matched the testbed data, confirming the accuracy of the model, with deviations within 5%. Building on this validated model, a hydrogen–gasoline dual-fuel engine simulation was developed. The predictive simulation revealed an approximately 5% increase in overall engine efficiency at the optimal operating point, primarily due to hydrogen’s combustion properties. Additionally, the injected gasoline mass and CO2 emissions were reduced by around 30% across the RPM range. However, the introduction of hydrogen also resulted in a slight reduction (~10%) in torque, attributed to the lower volumetric efficiency caused by hydrogen displacing intake air. While CO emissions were significantly reduced, NOx emissions nearly doubled due to the higher combustion temperatures associated with hydrogen. This research demonstrates the potential of hydrogen–gasoline dual-fuel systems in reducing carbon emissions, while highlighting the need for further optimization to balance performance with environmental impact.

Performance and Emission Analysis of a CI Engine Fueled with Preheated Neem Straight Vegetable Oil-Diesel Blend at Various Compression Ratios

The twin crisis, fast depletion of limited conventional fuel and environment degradation due to these fuels created a dire need to search for clean, green and sustainable alternatives to conventional fuels. Neem vegetable oil may be an alternative of conventional petroleum fuels due to its abundant availability in India and comparable physical and chemical properties. In the present study, performance and emission characteristics of VCR diesel Engine were observed using preheated and blended straight Neem oil. Initially experimentation was carried out to optimize the neem oil blend at engine optimize conditions which was given by manufacturer but this part is not considered in this research paper. Optimize Neem oil blend B30 (30% Neem oil and 70% Diesel) was used as fuel in the current study. Heat exchanger was design and developed to preheat the blended Neem oil up to 90 to 100 °C using engine exhaust gases. This temperature is sufficient to bring viscosity of blended Neem oil about viscosity of diesel. Performance emission characteristics of diesel engine were evaluated at compression ratios 18, 19, 20, 21 and 22. It was observed that at compression ratio 22, brake thermal efficiency of the engine was found optimum 34.99% using preheated optimum blend B30 which was higher than other compression ratios, diesel (1.64%) and unheated optimized same blend (5.07%). Less emission was observed for pre heated optimized blend B-30 as compared to other compression ratios, diesel and optimized same blend. Smoke opacity, CO, HC, NOx emissions at CR 22 for preheated NOB30 observed lowest 33%, 0.15%, 20 PPM and 340 PPM at full load condition.

Experimental Study on the Effect of Ammonia on Combustion and Emission Characteristics of a Spark Ignition Engine Fueled with Hydrogen.

Using hydrogen and its compounds as fuel is one of the key ways to achieve zero carbon emissions in internal combustion engines. Due to the difference in fuel properties of hydrogen and ammonia, mixing the two can make up for each other's shortcomings in combustion performance. Therefore, this paper studies the effects of ammonia addition on the combustion and emission characteristics of a SI commercial hydrogen engine, and studies the differences in these effects under different excess air ratios. The results indicate that increasing the ammonia mass ratio lengthens both flame development and combustion duration, causing a delay in the combustion center. Under stoichiometric conditions, combustion instability increases, peak cylinder pressure and heat release rate decrease significantly, and exhaust temperatures rise. With a higher ammonia mass ratio, brake-specific fuel consumption first decreases and then increases, reaching a minimum at a 0.4-0.6 ammonia mass ratio. Unburned ammonia and N2O emissions gradually increase, while NO X emissions initially rise and then fall, peaking at a low ammonia mass ratio. From the perspective of balancing emissions and fuel economy, for hydrogen-ammonia mixed combustion engines, a 0.6 ammonia mass ratio is recommended under stoichiometric conditions, while lean burn conditions allow for a higher ammonia mass ratio.

Multi‐aspect assessment and multi‐objective optimization of preheated tallow biodiesel‐diesel blend as alternate fuel in CI engine

AbstractThis study meticulously examined the impact of preheated tallow biodiesel on the performance and emission characteristics of a diesel engine. Employing a single‐cylinder, water‐cooled diesel engine configured with exhaust gas recirculation in this investigation, exhaust gas temperature (EGT) could be used to preheat the biodiesel, reducing its viscosity and density. This improvement in viscosity and density could enhance the injection process, which is often hindered by the higher density and viscosity of biodiesel compared with diesel fuel. The investigation achieved a peak preheat temperature of 70°C for the biodiesel, leading to notable improvements in brake thermal efficiency and brake power, particularly under high‐load conditions. A significant reduction in emissions was observed, with hydrocarbon and carbon monoxide levels decreasing by 46.87% and 50%, respectively, when using preheated biodiesel. To refine the engine's performance further, this study utilized response surface methodology (RSM) for the optimization of operational parameters, including injection timing, engine load, and biodiesel preheat temperatures. Optimal conditions were identified at an injection timing of 21° before top dead centre, a preheat temperature of 64°C, and an engine load of 45.45% for which output response was 18.68% brake thermal efficiency, 307°C EGT, 0.0247% vol. CO, 15.32 ppm hydrocarbons, and 131.37 ppm nitrogen oxides (NOx). The successful implementation of preheated tallow biodiesel signifies a crucial step forward in the pursuit of a more sustainable and efficient transportation industry. This advancement holds the promise of reducing reliance on traditional fossil fuels, thereby contributing to the global efforts towards achieving a more environmentally friendly energy landscape.

Effects of isopropanol-butanol-ethanol on the performance, combustion and emission characteristics of a diesel-methanol dual-fuel engine

Both diesel-methanol dual-fuel (DMDF) combustion and the addition of isopropanol-butanol-methanol (IBE) into diesel are capable of reducing the fossil fuel usage and soot emissions of diesel engines, but few of studies focused on combining the advantages of these two methods. Thereby, diesel containing 10 %, 20 % and 30 % of IBE by volume were utilized as pilot fuel in this study to investigate how the addition of IBE into diesel affects the performance, combustion and emissions of the DMDF engine. Experiments were performed at the engine load of 20 %, 40 % and 60 % with the engine speed fixed at 1400r/min. The results show that at most test conditions, the brake thermal efficiency of the DMDF engine only suffers a slightly drop while the soot emissions greatly reduce when IBE is blended into the pilot fuel diesel. Moreover, the deterioration of CO, HC and NOx emissions of DMDF engine can be significantly improved by blending no more than 20 % vol. IBE into the pilot fuel diesel. Additionally, with the volume ratio of IBE into the pilot fuel diesel increases to 30 %, the soot emissions of the DMDF engine can be further reduced at the costs of engine performance deteriorates and CO, HC, NOx emissions increase. Although the deterioration of the engine performance caused by the addition of IBE into the pilot fuel diesel can be mitigated by increasing the methanol flow rate, NOx emissions increase significantly.

Assessing the performance, and emissions characteristics of a diesel engine fueled with soya seed biodiesel blended with Oxy-hydrogen

The primary objective of this study is to assess the emission and performance characteristics of a soya seed oil biodiesel-hydrogen blend. Biodiesel was synthesized from soya seed oil via the transesterification process. The two biodiesel blends of S20 and S40, containing 20% and 40% biodiesel blended with neat diesel fuel were tested under different load conditions (25%, 50%, 75%, and 100%), with the engine operating at a constant speed in an unmodified conventional diesel engine. The biodiesel blends resulted in a decrease in brake thermal efficiency compared to pure diesel. However, adding hydrogen to the blends led to an improvement in BTE. Moreover, hydrogen addition significantly reduced the brake-specific fuel consumption for biodiesel blends. Due to hydrogen's higher flammability compared to diesel and biodiesel, the blends showed improved BTE without a corresponding increase in fuel consumption. The addition of biodiesel (20-40%) to diesel showed a reduction in emissions of carbon dioxide, carbon monoxide, and hydrocarbons than the neat diesel. However, no reduction in nitrogen of oxides (NOx) emissions was observed, largely due to the increased cylinder temperature attributed to the chemical composition of biodiesel. However, the introduction of hydrogen had a positive impact on emission characteristics, particularly reducing NOx emissions by 7.3%. Overall, the integration of hydrogen with biodiesel proves to be a promising strategy for enhancing combustion performance and reducing reliance on fossil fuels, while also improving emissions performance.

Effect of fuel characteristics coupled with injection parameters on oil–gas mixing and combustion processes in diesel engines

The physicochemical properties of fuels are critical determinants of the in-cylinder processes, overall performance, and emission characteristics of internal combustion engines. The distinctive characteristics of various fuels during atomization, evaporation, oil–gas mixing, ignition, and combustion phases play a decisive role in determining the combustion efficiency, thermal efficiency, and formation of pollutants. This study conducts a comprehensive comparative analysis of the physical and chemical properties of five distinct fuels, focusing on their interactions with the injection parameters. This investigation delineates the influence of these properties on the spray breakup dynamics and subsequent combustion processes. Results demonstrate that while the fuels exhibit varying sensitivities to injection parameters, optimal combustion performance is consistently achieved when the injection timing is set at 22° Before the Top Dead Center(BTDC), the nozzle orifice diameter is 0.32 mm, and the beam angle is maintained at 160°. This analysis provides novel insights into the complex coupling effects of fuel properties and injection strategies on in-cylinder processes, thereby contributing to the design and development of high-efficiency, low-emission internal combustion engines.

Enhancing Jatropha oil biodiesel by using Citrus Limetta peels as a biocatalyst: A sustainable way to reduce emissions and enhance the efficiency of CI engine

Biodiesel has become one of the promising alternative fuel resources for petro-diesel. Biodiesel is obtained by mixing oil and alcohol through transesterification reaction. A catalyst (base or acid) is typically added to accelerate the transesterification reaction and yield the maximum biodiesel production. The use of the traditional catalyst has problems like catalyst separation, soap formation, high reaction time, more energy consumption and environmental pollution. Literature shows that the addition of a catalyst from organic sources can overcome these problems. Biocatalysts were produced from different bio-waste like animal bones, plant leaves, fruit and vegetable peels, but there is no work found on the effects of Citrus Limetta peel waste for the biodiesel production. In this work, the feasibility of using Citrus Limetta peel ashes as an eco-friendly biocatalyst was investigated for the biodiesel production from Jatropha oil. The biocatalyst was obtained from Citrus Limetta peel waste after drying, pulverizing and calcination. XRD, SEM and EDX were used for the characterization of the biocatalyst. The biodiesel was tested for conformance with Euro standards. Then, three biodiesel blends (JT90, JT80 and JT70 with 10, 20 and 30 % biodiesel) were tested for determining the engine performance and emission characteristics in a Kirloskar 4-stroke CI diesel engine. SEM and EDX indicated a substantial concentration of potassium (26.8 %) and calcium (71.59 %) in the biocatalyst. The maximum biodiesel yield was achieved with 2 wt% biocatalyst, 15:1 Jatropha-to-methanol molar ratio, 60 °C reaction temperature and 1 h reaction time. Engine performance study showed that the JT80 blend demonstrated a BTE improvement of 1.2 % with a significant BSFC reduction of 11 % when subjected to full load conditions, surpassing that of pure diesel. Emissions study revealed that the JT80 blend demonstrated a substantial decrease in emissions compared to pure diesel. Specifically, there was a noteworthy 10.3 % reduction of carbon monoxide (CO), 14 % of carbon dioxide (CO2), 11 % of unburnt hydrocarbon (HC) and 3 % of nitrogen oxides (NOX), but with an increase of 2 % in smoke emissions.

Experimental investigation on diesel engine performance and emission characteristics using waste cooking oil blended with diesel as biodiesel fuel

Biodiesel production from waste cooking oil is a potential feedstock to alternative fuel sources. Produced alternative fuel sources were to have a strong emphasis on energy efficiency to substitute the declining world supply of fossil fuels while also improving emission characteristics in diesel engine applications. The development of industrialization and mechanization causes increased fossil fuel consumption and its usage. This study aimed at an experimental investigation of biodiesel blended fuel combustion efficiency for single-cylinder diesel engines under varying engine loads at constant engine speed 1500 rpm. The transesterification process was used to produce biodiesel from waste cooking oil using NaOH as catalysts. Biodiesel reaction takes place with oil to methanol ratio of 6:1 at 60 °C reaction temperature for 90 min with 600 rpm stirring speed while 90% yield gained. Eight sample biodiesel blends were prepared with percentage value B5%, B10%, B15%, B20%, B25%, B30%, B35%, B40% v/v and B100% to investigate the effect of biodiesels on engine performances. The experimental result reveals that the mixed biodiesel blends have lower average value in terms of brake torque, brake power, and brake thermal efficiency than diesel fuels as a percentage of 16.79%, 4.08%, and 27.9% respectively. In addition, the average BSFC of biodiesel blends was increased by 4.8% than baseline diesel fuel. Related to exhaust gases emission test results were shows that the average CO and HC emissions decreased by 52.2% and 60% with increasing loads and blends and the increment of CO2 and NOx by 28.1% and 45.4% respectively than baseline fuel with increasing blends and loads. Biodiesel derived from waste cooking oil was less costly and environmentally friendly and viable to substitute petro-diesel.

Enhancing Combustion Efficiency: Utilizing Graphene Oxide Nanofluids as Fuel Additives with Tomato Oil Methyl Ester in CI Engines

The research aims to conduct a thorough examination of the combustion, injection, performance, and emission characteristics of a diesel engine below different engine loads, as well as the synthesis of graphene oxide (GO) nano fuels and their utilization in combination with Tomato Oil methyl ester (TOME) and diesel fuel blend. The graphene oxide, plays a vital role in the pre-mixed combustion phase of diesel engines. Addition of graphene oxide nano fuels enhances the high-pressure combustion stage, resulting in increased maximum pressure and heat release rate. TOME (B20GO75) and TOME (B20GO100) exhibit comparable heat release rate to diesel due to improved fuel characteristics and quicker ignition delay duration. While TOME (B20) shows a slight decrease in (BTE) compared to diesel, the addition of graphene oxide improves BTE, with TOME (B20GO50) displaying the highest BTE at full load, indicating enhanced combustion efficiency. Moreover, graphene oxide addition leads to a reduction in carbon monoxide (CO) and hydrocarbon (HC) emissions, with emissions decreasing as the concentration of graphene oxide increases. However, NoX emissions initially decrease with TOME (B20) compared to diesel but increase with higher graphene oxide concentration. Smoke emissions increase with TOME (B20) but decrease with higher graphene oxide dosages. Overall, the incorporation of graphene oxide nano fuels into Tomato Oil methyl ester blends demonstrates potential for improving engine performance and reducing emissions.

Investigation into the impact of acetylene on performance and emission characteristics of a compression ignition engine using a blended biodiesel of ethanol and tamanu oil.

Due to the significant increase in transportation, traditional fossil fuels utilised in internal combustion engines will only be accessible for a limited duration. Additionally, the harmful pollutants produced by these fuels, including CO, NOx, unburned hydrocarbons, smoke, and a small amount of particulate matter, have a severe negative impact on the environment. Although biodiesel proves efficient without necessitating engine modifications, its performance is hindered by its higher viscosity. Consequently, this research aims to enhance performance by introducing acetylene alongside tamanu methyl ester (biodiesel); however, this approach results in elevated NOx levels. To mitigate NOx emissions, a combination of ethanol and biodiesel is employed. This study investigates the performance and emission attributes of Acetylene + TME90E10 as the fuel. The combustion pressure and heat release rate of TME90E10 with 6 lpm, improved by 5.41% and 9.1% than diesel. When compared to regular diesel fuel, the introduction of 6l per minute of acetylene with TME90E10 yields a substantial 24.4% decrease in hydrocarbon (HC) emissions. Furthermore, employing TME90E10 at the same acetylene flow rate demonstrates the lowest carbon monoxide (CO) emissions, registering at 0.07%, in contrast to the 0.13% emissions observed throughout the exhaust cycle when using pure diesel fuel.

Experimental study of ammonia energy ratio on combustion and emissions from ammonia-gasoline dual-fuel engine at various load conditions

Achieving carbon neutrality necessitates the adoption of zero-carbon fuels in engine applications, with ammonia emerging as an up-and-coming candidate due to its favorable safety profile and advantages in storage and transportation. This study experimentally investigated the feasibility of an ammonia-gasoline dual-fuel (AGDF) engine to achieve comparable power output and satisfactory carbon reduction without changing the main structural parameters of the engine. A four-cylinder, naturally aspirated, spark ignition engine was used to investigate the impact of ammonia energy ratio (AER), engine base torque and engine speed on the engine performance, combustion evolution and emission characteristics. The findings reveal that the brake thermal efficiency (BTE) in AGDF mode is lower than in gasoline-only mode, primarily due to the reduced combustion activity. However, this efficiency decline becomes noticeable only when the AER exceeds 15 %. Additionally, at high AERs and high engine base torques, the delayed effect of ammonia fuel on the main combustion period results in a double-peak pattern, which limits the energy output but presents opportunities for phase optimization. The study also examined three incomplete combustion emissions, each exhibiting distinct behaviors. Except for ammonia slip, adding ammonia fuel does not significantly affect carbon monoxide (CO) and unburned hydrocarbons (UHC) emissions, particularly at AERs below 25 %. Nevertheless, nitrogen oxide (NOx) emissions under AGDF combustion are significantly higher than under gasoline alone in most instances. Crucially, the study demonstrates the carbon reduction potential of ammonia fuel across different engine loads, with a maximum carbon dioxide (CO2) reduction of 46.8 % at a 35 % AER. It is anticipated that further optimization of the combustion phase will improve the capability for carbon reduction.

Performance analysis of dual-fuel engines using acetylene and microalgae biodiesel: The role of fuel injection timing

This study evaluates the impact of varying fuel injection timing (FIT) and dual-fuel modes on the performance and emissions of a compression ignition (CI) engine under different load conditions. The biodiesel used was derived from Chlorella protothecoides microalgae through a two-step transesterification process, and its elemental composition was characterized using gas chromatography-mass spectrometry (GC-MS). Acetylene gas was introduced into the engine intake manifold at a rate of 3 L per minute (LPM), while a blend of 20 % methyl ester from Chlorella protothecoides (B20 MEOA) served as the primary injected fuel. To predict engine performance and emission characteristics, advanced machine learning models were employed and evaluated using four statistical criteria, including R-squared, mean absolute error (MAE), and mean squared error (MSE). Experimental results indicated that the optimal configuration involved a dual-fuel mode combining B20 MEOA with acetylene gas and an advanced FIT of 25° before top dead center (bTDC). Performance analysis revealed that under all load conditions, the specific fuel consumption (SFC) decreased by 7.3 %, while brake thermal efficiency (BTE) increased by 1.6 % compared to conventional diesel. Emission testing showed a 7.6 % rise in nitrogen oxide emissions, alongside significant reductions in unburned hydrocarbons (12.5 %), carbon monoxide (25.6 %), and smoke intensity (7.5 %) relative to standard diesel operation. Optimization of the engine parameters ensured that key metrics, such as brake power (BP) and brake-specific fuel consumption (BSFC), remained within acceptable limits. The random forest model outperformed other machine learning models, demonstrating superior accuracy in predicting performance and emissions across all statistical measures. This study underscores the potential of combining advanced biodiesel blends with optimized FIT strategies to improve engine efficiency and emissions control, offering a promising approach for sustainable dual-fuel engine operations.

Effect of hybrid nanoparticles dispersed ternary fuel blend on diesel engine performance and emissions: Experimental and Taguchi-Grey relation study

The present study deals with the influence of hybrid nanoparticles dispersed in ternary fuel mixtures on the evaluation of the performance and emission characteristics of a single cylinder diesel engine. The fuel blend consists of 70 % diesel, 20 % Madhuca longifolia biodiesel, and 10 % ethanol (by volume). The hybrid nanoparticles of ferric chloride (FeCl3) and graphene nanoparticles were then added to this ternary fuel mixture in different proportions, namely 50 mg/L and 75 mg/L, together with the surfactant and the dispersant in a ratio of 1:1. Moreover, the experiments were conducted on a diesel engine to evaluate the performance and emission parameters by varying different fuel samples, different loads (3, 6, 9, and 12 kgf) and injection pressures (i.e. 200, 225,and 250 bar). In addition, the Taguchi-Grey relation analysis was used for optimization, and the input parameters are fuel samples, loads and injection pressures. Experimental performance metrics, including brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE), were improved when hybrid nanoparticles were added to the ternary fuel blend compared to diesel. At the same time, smoke opacity, nitrogen oxides (NOx), unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions were reduced. Increasing the injection pressure also led to positive results, apart from NOx. Both performance and emissions were better for hybrid nanofuel based on surfactants and dispersants than for the base fuel, and it performed better of all dispersant-added nanofuels. The better results were obtained with D70B20E10NPs75QPAN75 mg/L than with the other fuel samples. The maximum BTE and lowest BSFC are 33.26 % and 0.206 kg/kWh, while the minimized CO, UHC, NOx and smoke values at full load are 0.019 %, 21 ppm, 833 ppm and 36.25 %, respectively, at full load and injection pressure of 250 bar By combining experimental investigations with the Taguchi -Grey method, a comprehensive and rapid assessment of the effects on the performance and emission characteristics of diesel engines was achieved.