Single Cylinder Diesel Engine Research Articles

Experimental Investigation on the Effect of Graphene Oxide in Higher Alcohol Blends and Optimization of Injection Timing Using an ANN Method.

The use of alternative fuels in diesel engines has become more widespread due to a number of factors, including dwindling petroleum supplies, increasing prices for conventional fossil fuels, and environmental worries about pollutants and greenhouse gas emissions from internal combustion engines. Efficiency and emissions need to be appropriately balanced. Alcohols act as oxygenated fuels similar to octanol, offering a number of benefits over traditional fuels and can boost efficiency, enhance combustion, and reduce air pollution. Therefore, the research aimed to enhance the performance and combustion characteristics of a diesel and octanol blend using graphene oxide (GO) nanoparticles as a fuel additive in a single-cylinder diesel engine while reducing emissions. Research findings will contribute significantly to improving the physical and chemical properties of diesel and octanol blends, thereby mitigating the challenges of limited petroleum reserves and environmental concerns. A range of different blends of diesel and octanol were prepared on a volume/volume basis in proportions of D70OCT30, D60OCT40, and D50OCT50, and then GO was added as a fuel additive to the abovementioned blends in varied proportions (40, 60, and 80 ppm) resulting in nine blends. These blends were analyzed in terms of various performance, combustion, and emission characteristics, and the obtained results helped to shed light on the impact of GO as a fuel additive. The results indicated that the fuel blend D70OCT30GO0.006 yielded the highest values. Furthermore, it is highly imperative that we develop a model that can be used to predict engine behavior and its stability without having to run an engine. For this, a data-driven artificial neural network (ANN) model was developed to predict the optimized injection timing for better combustion and reduced emission. The efficiency and prediction capabilities of the model were compared to the experimental data, which indicated that the ANN model had a better prediction score. The injection timing of the engine was optimized from 21 °CA to 21.5 °CA, which increased the efficiency by 1%. The research findings showed significantly improved physical and chemical properties of the blends, thereby mitigating the challenges of limited petroleum reserves and environmental concerns.

Numerical investigation of soot formation in diesel jet flame with KIVA-3V

Diesel engines emit a Large amount of pollutants essentially soot particles. This paper describes a 3D modeling on platform of a 3-D code for engine thermodynamic simulation Kiva-3V. A Hiroyasu model for soot formation was used originally, it’s a twostep Empirical model has been implanted in the code. This study was conducted to predict the emission of pollutants such soot more accurately and to enhance understanding of the pollutant formation process. The simulation was carried out by using a supercharged direct injected single cylinder diesel engine for heavy-duty applications.

Numerical Analysis to Investigate the Impact of Skirt Geometric Parameters on Secondary Piston Movement in a Single-cylinder Diesel Engine

Currently, modern internal combustion engines are receiving great attention due to their efficiency, particularly in response to the increasing limits imposed by environmental and emission legislation. Sound emissions of internal combustion engines are mainly caused by three sources of noise: combustion, mechanical and aerodynamic flow. The secondary motion of the piston plays a crucial role in the analysis of performance, noise, vibration and reliability of internal combustion engine (ICE). In the presented article, a mathematical simulation model has been developed by using of the GT-Suite software to study the rotational and lateral motion of the piston (called secondary motion) as well as the piston slap in ICE. This model takes into account the effect of variation in the major geometric parameters of the skirt design, such as the piston pin offset (P.P.O) and the length of the skirt. Furthermore, a combined model that accounts for the interplay between the secondary dynamics of the piston and the dynamic fluid lubrication has been developed. This model utilizes a mixed lubrication approach for the purpose of simulation. The results of this simulation have demonstrated that the variations in length of the skirt and the P.P.O have a considerable effect on piston secondary motion and tribological performances, and that the lateral motion of the piston is significantly influenced by the piston side force, which plays a crucial role in this behavior.

Effect of NOx and Mechanical Efficiency in Single Cylinder Diesel Engine using Multiple Injection of Biodiesel- An Experimental Investigation

Effect of NOx and Mechanical Efficiency in Single Cylinder Diesel Engine using Multiple Injection of Biodiesel- An Experimental Investigation

ENGINE PERFORMANCE TEST EVALUATION OF BIODIESEL BLENDS FROM CASTOR SEED OIL AT VARYING MIXTURE RATIOS AND ENGINE SPEED

The growing global demand for energy with expected fossil fuel shortages stresses the search for alternative energy sources. Moreover, the high fossil energy consumption with its adverse impact on environment and climate changes calls for cleaner fuels. One of the most alternative fuel sources is the extraction of biofuels from Castor oil by acid-based catalysed trans- esterification process. In this study, experimental analysis was carried out to produce biodiesel from castor oil using trans- esterification process. The trans- esterification process occurs between castor oil and methanol in the presence of potassium hydroxide (KOH) as a catalyst. The biodiesel fuel produced was varied at different mixture ratios with diesel. The high viscosity and acid value of the castor oil was further reduced by two-three stage trans-esterification process to within the American Society for Testing and Materials (ASTM) D6751 – 0.2 limits for biodiesel. The biodiesel was tested in a single cylinder diesel engine and results of gas emission, load analysis, fuel consumption rate and engine efficiency were all obtained which are close to those of diesel fuel thus confirming that it can be used as alternative fuel for diesel engines. The Brake thermal efficiency was 96% at B-20 biodiesel blend which is close to the conventional diesel engine efficiency of 95.5%.

Prediction modeling using artificial neural network (ANN) for the performance and emission characteristics of catalytic co-pyrolytic fuel blended with diesel in a CI engine.

In the present research work, artificial neural network (ANN) is used to model the performance and emission parameters in a four-stroke, single-cylinder diesel engine combusting a blended fuel of diesel and catalytic co-pyrolysis oil produced from seeds of Pongamia pinnata, waste LDPE, and calcium oxide catalyst. The optimum yield of oil obtained was 92.5% at 500 °C temperature. Physical properties of the obtained oil, such as calorific value (44.85 MJ/kg) and density (797 kg/m3), level it by that of diesel while the flash point and fire point were found to be lower than that of pure diesel. An ANN model was then generated for the prediction of performance characteristics (BTE and BSFC) and emission characteristics (NOx and smoke) under varying loads, braking power, brake mean effective pressure, and torque as inputs using the Levenberg-Marquardt back-propagation training technique. The regression coefficients (R2) for BTE, BSFC, smoke, and NOx predictions were determined to be close to unity at 0.99859, 0.99814, 0.96129, and 0.92505, respectively (all values being close to unity). It has been discovered that ANN makes an effective simulation and prediction tool for blended fuels in CI engines. It is also suggested to predict the mechanical efficiency, volumetric efficiency, and CO, CO2, HC emissions using ANN in its future work.

Multi-objective parameter optimization for four-stroke single-cylinder diesel engine with soyabean oil blends using NSGA-II

Due to the continuous scarcity of petroleum and related products, there is a greater need for alternative product to petroleum derivatives. The current work investigates the factors influencing the output characteristics of a single-cylinder four-stroke compression ignition engine by utilizing different combinations of blends of soybean biodiesel and fossil diesel, by weight/weight. The experiments have been conducted using the Response Surface Method based on full factorial CCRD and NSGA-II. Mathematical models for BSFC (brake-specific fuel consumption), BTE (brake thermal efficiency), and emission (CO, NOx, and unburned HC) have been proposed using regression equations for optimizing the combustion characteristics (brake-specific fuel consumption), performance characteristics (brake thermal efficiency), and emission parameters (CO, NOx, HC) in NSGA II. A multi-objective optimization problem is created since this investigation aims to minimize BSFC, CO, NOx, and HC and maximize BTE. This research evaluated five optimum combinations of BSFC, BTE, NOx, CO, and HC at variable input factors’ blending ratio and load, and their conformity was checked. It is observed that at a blending ratio of 25.03, the engine performance and emission give better results. At a blending ratio of 25.03% w/w and load 2.08 kW, the brake thermal efficiency is 24.96%, and emission parameters are NOx 52.56 ppm, CO 0.08%, and hydrocarbon 18.11 ppm.

Experimental and numerical study on direct injection of liquid ammonia and its injection timing in an ammonia-biodiesel dual injection engine

Ammonia is an alternative carbon-free fuel that can be easily stored in a liquid phase, unlike hydrogen, and then directly utilized in diesel engines. Hence, a single-cylinder diesel engine was retrofitted for direct injection of liquid ammonia with pilot ignition of biodiesel in dual fuel combustion mode. The effects of the liquid phase of ammonia and ammonia energy share (AES) on combustion, emissions, and engine performance were investigated and compared with pure biodiesel operation. Moreover, various ammonia injection timings were studied to improve ammonia/biodiesel combustion and reduce emissions. A CFD model was developed and validated with experimental data to study ammonia/biodiesel sprays, combustion characteristics, and emissions formation. The results showed higher AES significantly reduced the local cylinder temperature due to the strong cooling effects of ammonia, therefore, a maximum AES of 50% was achieved. Increasing AES to 50% decreased combustion duration and combustion phasing by 26.2 and 4.4 CAD, respectively. However, it deteriorated the indicated thermal efficiency (ITE) by 1.3 percent point compared to pure biodiesel. Furthermore, retarding ammonia injection from −25 to −10 CAD significantly reduced NOx, CO, and ammonia emissions by 31.4%, 39.6%, and 31.3%, respectively. Ultimately, the optimal operating condition was suggested when ammonia was injected at −10 CAD and biodiesel at −16 CAD with AES of 50%.

Performance analysis of Single-Cylinder CI Engine with Turmeric Leaf Oil Biodiesel at Different Operating Conditions

Biodiesel, made from vegetable oils, non-edible oils, and animal fats, is a promising diesel alternative. The performance of a single-cylinder diesel engine using turmeric leaf oil biodiesel is examined in this study. Three biodiesel blends—B10, B20, and B30—were tested against diesel fuel. The highest brake thermal efficiency (BTE) of 24.84% and the lowest brake-specific fuel consumption (BSFC) of 0.28 kg/kWh were achieved using diesel fuel at 600 bar injection pressure, 18 compression ratio, and full engine load. With the same operating conditions, biodiesel blends B10 (23.84% and 0.29 kg/kWh), B20 (23.38% and 0.32 kg/kWh), and B30 (23.22% and 0.34 kg/kWh) had BTE and BSFC values.

Ozone-assisted combustion and emission control in RCCI engines: A comprehensive study

This paper presents an investigation into the combustion and emission characteristics of reactivity-controlled compression ignition (RCCI) engines using ozone seeding, which is known as one of the most highly oxidizing chemical species. The study aims to address challenges pertaining to combustion control and emissions deterioration. Therefore, the current work investigates the RCCI mode of operation in a single-cylinder diesel engine with intake air that has been seeded with ozone by introducing conventional diesel fuel as a high-reactivity fuel using a high-pressure direct injection method and iso-octane as a low reactivity fuel using a low-pressure port injection method. In the experimental study, different ozone concentrations up to 300 ppm and three different energy-based premixed ratios of low reactivity fuel from 0% to 45% with a 15% rise rate were examined under various engine loads and constant engine speed. The methodology used in this research provided for simultaneous decreases in unburned hydrocarbon (HC) emissions and smoke opacity for RCCI engines. According to the experimental findings, simultaneous utilization of RCCI mode and ozone seeding led to a decrease of up to 36% in HC emissions and a reduction of up to 98.7% in smoke opacity. Moreover, nitrogen oxides (NOx) emissions were reduced by up to 39.5% at 20% engine load, whereas carbon monoxide (CO) emissions exhibited a decrease of up to 46% at 60% load. The RCCI mode also yields significant reductions in pollutant emissions and notable increases in brake thermal efficiency (BTE) when compared to the conventional diesel mode (CDM). In conclusion, this experimental study presents a promising solution for addressing emissions deterioration in RCCI engines while simultaneously achieving reductions in pollutant emissions.

Analysis of Sound Emission Using Ternary Blend Fuel in Compression Ignition Engine

Alternative fuel is considered to be suitable oils in diesel engines, which are well known for their ability to diminish lubricant oil debris and noise emissions. A minute research has been done to examine the long-term effects of using blend fuel. In this study, two blend fuels: diesel and waste cooking oil (DF95WCO5), and diesel, waste cooking oil and n-pentanol (DF65WCO20Pe15) were chosen and compared with diesel fuel (DF) to investigate the impact of these blends on noise emission in diesel engine. In order to evaluate the kinematic viscosity and density and determine the effect on sound pressure levels, lubrication oil samples were taken throughout the test at intervals of 20 hours. A literature review was done for the current work's analysis of the literature on the noise emissions from diesel-waste cooking and n-pentanol fuel blends. When the engine was fueled with DF65WCO20Pe15 blend, the engine lubricating oil analysis revealed an extreme wear issue, decreased viscosity, and increased density values. The conclusion is that single cylinder diesel engines can use binary blend DF95WCO5 and ternary blend DF65WCO20Pe15 without any adjustments. DF65WCO20Pe15, in contrast to the reference fuel, achieved some superior outcomes.

Investigation of conversion of a diesel engine to homogeneous charge compression ignition engine using n-heptane: A zero-dimensional modeling

Numerical methods are commonly used for analyzing combustion characteristics. Besides, they provide an opportunity to predict emissions of an engine. In this paper, the conversion of a single-cylinder diesel engine to HCCI combustion model is investigated with AVL Boost v2021R2. The model was used to simulate the power, emission, bsfc value. In-cylinder pressure results also are obtained from the model. Verification of the model is conducted with experimental data from the literature. The differentiation between the numerical and experimental results remained below 8.9% for the power, below 6.62% for bsfc. In addition to this, the model gave maximum pressure values with an accuracy of ± 1%, and maximum HRR values with an accuracy of ± 2%. Maximum HRR values and in-cylinder pressure curves for 1200-2400 rpm were obtained with acceptable accuracy. Besides, the operating range of an HCCI engine fueled with n-heptane was investigated using a zero-dimensional single-zone model with reduced fuel chemistry. The compression ratio and inlet air temperature effect on HCCI combustion were analyzed. The increasing the air inlet temperature to 40oC from 20oC, increases the lowest air-fuel ratio about 6.6% which the engine can operate without entering the knock zone, at 17.5 CR at 1200rpm.

Development of artificial neural network and response surface methodology model to optimize the engine parameters of rubber seed oil – Hydrogen on PCCI operation

Identifying the suitable alternative fuel and optimum blend concentration for diesel engine combustion is critical as most biodiesel emits excess smoke and has a lower thermal efficiency due to its high viscosity and carbon residue. In the previous work, rubber seed oil was tested in a single-cylinder diesel engine, and its performance and emission results were compared with those of pure diesel, an RSO-diesel (70:30 by volume) blend, RSO-methyl ester, RSO-diethyl ether, RSO-ethanol, and RSO-hydrogen in a dual fuel operation. The testing was performed at a constant speed of 1500 rpm, with the engine loads varying at 25% step intervals. Results showed that smoke and nitrogen oxides were significantly reduced for RSO, and engine performance was enhanced when RSO was operated with hydrogen and diethyl ether in dual fuel mode. In this study, the experimental results were employed to develop an artificial neural network and response surface methodology model. Brake thermal efficiency, rate of pressure rise, carbon monoxide, hydrocarbon, oxides of nitrogen, and smoke were predicted using response surface methodology and artificial neural network. Though artificial neural network produced the best R2 values (0.87264–0.99929), mean absolute percentage error was relatively lesser in response surface methodology. Thus, the authors conclude that response surface methodology is the best suitable artificial intelligence tool to optimize the engine for accomplishing desired responses.

Mechanism of the reduction in afterburning and thermal efficiency improvement with highly oxygenated fuels in diesel combustion

Highly oxygenated fuels can effectively reduce afterburning in diesel diffusion combustion and improve the degree of constant volume heat release in spite of increases in injection duration due to smaller heating values. The mechanism of afterburning reduction and the structural differences in the diesel fuel spray with changing the oxygen content in the fuel were investigated in a constant volume vessel and analyzed with 3D CFD simulation. The result showed that the equibalance ratio inside the spray decreased with increases in the oxygen content due to lower theoretical air-fuel ratios, promoting the spray combustion after the end of injection. Further, the combustion characteristics and the exhaust gas emissions of the oxygenated fuels were investigated in an experimental single cylinder diesel engine with modern specifications. With increasing oxygen contents, the degree of constant volume heat release increased with reductions in the afterburning, resulting in higher indicated thermal efficiencies. However, the indicated thermal efficiency showed a maximum at around 27 mass% of the oxygen in fuel and further increases in the oxygen contents resulted in lower indicated thermal efficiencies due to larger cooling losses.

Combustion Process of the Compound Supply CNG Engine

Objective: In order to study the lean combustion process of a natural gas engine by separating the combustor, a spark ignition natural gas engine with separated combustors was retrofitted from a S195 single-cylinder diesel engine. Methods: The electronic control system controlled the gas supply and the spark plug ignition. A low pressure injection valve was set in the inlet pipe to form a lean mixture while a high pressure injection valve was placed in the subsidiary chamber to create a rich mixture, which was then ignited and injected into the main combustor, where the lean mixture was subsequently ignited again to achieve stratified combustion. Results: The test results showed that steady ignition is feasible in the system and verified the impact of the shape of the main combustor on HC, the impact of channel diameter on NOX production, and the impact of the ratios of high-pressure gas and low-pressure gas on HC and NOX. The combustion conditions of high-pressure gas and low-pressure gas in the engine combustor vary greatly. Our results signify that the shape of the main combustor has a great impact on the performance of the engine, that is, a shorter propagation distance can reduce the generation of HC. Conclusion: The best ignition advance angle under different conditions was determined using a spark ignition natural gas engine. The ratios of high-pressure gas and low-pressure gas greatly impact the performance and emission of the engine. The reduced diameter of the channels between the main and subsidiary combustors can enhance the stratification and facilitate the secondary ignition.

Performance-emission effect of n-butanol in Reactivity Controlled Compression Ignition regimes of biodiesel combustion

ABSTRACT A comprehensive investigation has been undertaken to explore the effect of split injection phasing under simultaneous port fuel-injected butanol-induced reactivity phasing on the standard biodiesel combustion regimes in an existing single-cylinder diesel engine. Experiments were conducted on a four-stroke single-cylinder CI engine coupled with a manifold intake system at a constant speed of 1500 rpm. Butanol injected (0 ms, 2 ms, 3 ms, 4 ms) through the PFI system was varied along with the split injection timing (55° PISA −23° MISA CA bTDC, 45° PISA −15° MISA CA bTDC, 35° PISA −5° MISA CA bTDC) and pilot injection quantity (25%, 50%, 75%) of Mahua biodiesel. Analysis revealed that the minimum brake-specific energy consumption and the highest exergy efficiency registered were respectively 28.86% lower and 110.29% higher than baseline biodiesel operation. The emission parameters of NOX, Soot, CO, and unburnt hydrocarbons under the induced RCCI regimes also registered a drastic 58.56%, 82.48%, 83.48%, and 97% lower footprint than baseline diesel operation at full load.

Influence of alumina nanoparticles additives into biofuel (water hyacinth)‐diesel mixture on diesel engine performance and emissions

AbstractThe using diesel and biodiesel blends as a fuel has been a recent field of study especially with nanoparticles additives. The addition of alumina nanoparticles to biodiesel was verified to reduce emissions, while engine performance was not given great attention to evaluate the effect of blending alumina nanoparticles with the diesel and biodiesel mixture on the performance characteristics of the diesel engine. Then performance and emission tests were carried out by using different fuel samples in a single cylinder diesel engine. The brake thermal efficiency for the alumina nanoparticles (50 ppm, 100 ppm) and biodiesel blends were lower than that of biofuel (D80B20) blends, it was decreased by 2.5 %, 6.05 % respectively as compared to the blend (D80B20). The rate of carbon monoxide emissions for the two biodiesel and alumina blends were lower than that of the biodiesel blend (D80B20) and the best reduction was for the blend (D80B20N50) and was 76.3 % as compared with the biodiesel blend (D80B20). Also, the nitrogen oxides emissions for all the blends with nanoparticles were lower than that of the blend D80B20 due to shortened ignition delay and less fuel was added during the combustion which lead to reduction in nitrogen oxides emissions.

The effects of metallic fuel addition into canola oil biodiesel on combustion, engine performance and exhaust emissions

In the current study, canola oil biodiesel was produced with transesterification method. Biodiesel was added to the neat diesel at the rate of 20% (B20). 50 ppm, 100 ppm and 150 ppm nanoparticles (Quantum Dots) were added to B20. The influences of fuels on combustion, performance and emissions were researched in a single-cylinder diesel engine. Engine experiments were performed at 2200 rpm and engine loads including 4.12, 9.61, 15.10 and 20.60 Nm. It was found that the difference in cylinder pressure between diesel and blended fuels decreased with the increase of engine load. Igntion delay (ID) was shortened with the addition of metallic fuel. Specific fuel consumption (SFC) decreased by 3.08%, 8.70% and 17.69% using D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to D80TCB20 at 15.10 Nm. Thermal efficiency increased by 83.74%, 89.09% and 89.30% using D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to D80TCB20 at 15.10 Nm. The lowest maximum pressure rise rate and ringing intensity were determined with neat diesel. HC reduced by about 1.75%, 5.26% and 7.01% D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to neat diesel at 20.60 Nm. Remarkable reduction was also observed on soot emissions. Soot emissions reduced 83.11%, 85.45% and 86.36% 1.75%, 5.26% and 7.01% D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to neat diesel at 20.60 Nm. On the other hand, NOx and CO emissions increased with the addition of nanoparticle.

Physical properties, engine performance, and exhaust emissions of waste fish oil biodiesel/bioethanol/diesel fuel blends

In the current study, the physicochemical, engine performance, and exhaust emission of different ternary fuel blends containing waste fish oil (WFO) biodiesel, bioethanol, and petro-diesel have been investigated. WFO Biodiesel was prepared from waste fish oil via transesterification method. Different physiochemical properties including the kinematic viscosity, density, flash point, pour point, cloud point, and heat value have been measured for different fuel blends and compared with the neat petro-diesel. The performance and exhaust emission of engine have been also studied using different fuel blends using a single-cylinder diesel engine in full load condition at 1800 rpm. It was found that the engine torque, engine power, and thermal efficiency of the ternary fuel blends was reduced by 2.45%, 9.25%, 2.35% averagely in comparison with the neat petro-diesel, respectively. The average break specific fuel consumption was also increased by 10.44% compared to the neat petro-diesel. The emission of carbon monoxide (CO), carbon dioxide (CO2), unburned hydrocarbons (UHC), and nitrogen oxides (NOx) was also measured. It was also found that the utilization of ternary fuel blends results in a considerable reduction in CO and UHC emission by 50.55% and 43.87% on average compared to the neat petro-diesel, respectively. The emission of NOx was also increased by 28.25% on average compared to the neat petro-diesel. It was also found that the NOx emission can be adjusted by tuning the WFO biodiesel and bioethanol contents of the ternary fuel blends.

Environmental and energy valuation of waste-derived Cymbopogon Martinii Methyl Ester combined with multi-walled carbon (MWCNTs) additives in hydrogen-enriched dual fuel engine

This study uses a Capparis Spinosa Methyl Ester or Cymbopogon Martinii Methyl Ester (CMME25) and hydrogen dual fuel engine using multi-walled multi-additive nanotubes (MWCNT). In this experiment, a single-cylinder diesel engine was used. Through the intake manifold, hydrogen is introduced at predetermined flow rates of 5 and 10 lpm. The enriched hydrogen MWCNT of 50 and 100 ppm is combined with the CMME25 fuel. Results from the first round of experiments showed that combustion characteristics and performance were improved by hydrogen enrichment. The addition of hydrogen in the CMME25 fuel blend exhibited better performance (BTE (2.52% higher at 5 lpm and 4.52% higher at 10 lpm), BSFC (1.8% lower at 5 lpm and 2.2% lower at 10 lpm), and increased combustion parameters with lower ignition delay and combustion duration and lower emission gases (CO (8.3% at 5 lpm and 13.4% at 10 lpm), HC (7.2% at 5 lpm and 13.1% at 10 lpm), smoke (4.27% at 5 lpm and 9.06% at 10 lpm)) except NOx emission (4.82% at 5 lpm and 8.16% at 10 lpm) when compared with CMME25 without hydrogen addition. The second phase discussed the effect of multi-walled nanotubes (MWCNTs) blended with CMME25 fuel enriched with hydrogen of 10 lpm. The addition of multi-walled nanotubes in the CMME25 fuel blend revealed that higher BTE and lower BSFC were observed. MWCNT nanoparticles operate as catalysts to accelerate combustion. Minimising ignition delay and HRR advances peak HRR. Hydrogen increased the hydrogen-carbon ratio, improved air/fuel mixing, and shortened combustion, reducing CO emissions. MWCNTs decreased HC emissions by catalysing fuel oxidation and combustion. NOx emission was 6.3 and 12.8% lower for MWCNT 50 and 100 ppm, respectively. Smoke emissions decreased by 8.1 and 14.22% for MWCNT 50 and 100 ppm. Nanoparticles improved fuel droplet evaporation, thermal conductivity, and smoke emission.