Pressure Release Rate Research Articles

Evaluating the effect of variable methanol injection timings in a novel co-axial fuel injection system equipped locomotive engine

Methanol has been identified as a potential substitute for conventional fuels (diesel, petrol) from scalability, sustainability, and an economic viewpoint. Economically, methanol could be cheaper than conventional fuels based on the price per MJ energy. This study evaluated the possibility of displacing the diesel (90% on an energy basis) by methanol in the locomotive engine using a novel co-axial injection concept while evaluating the different methanol injection timings. Pilot diesel injection (10% on an energy basis) ensured the combustion of injected methanol. A 1-D model of a 16-cylinder locomotive engine was developed for the parametric study to identify a suitable methanol injection strategy corresponding to co-axial injector configuration. Three different parameters were selected to investigate the effect of the new co-axial injection system on the engine performance, combustion, and emissions. These were (i) methanol injection timing, (ii) nozzle design parameters (hole diameters and the number of holes) for methanol injection, and (iii) nozzle design for diesel injection. Three different methanol injection strategies (ITM1, ITM2, ITM3) were evaluated at eight different notches of the locomotive engine for identical diesel injection timings of the validated base model. ITM1 emerged as the best strategy to inject methanol into the engine cylinder because of relatively higher in-cylinder pressure and comparable heat release rate (HRR). The maximum in-cylinder pressure (Pmax), the crank angle at maximum pressure (°CA Pmax), the start of combustion (SoC) duration, combustion duration (CD), and torque were comparable to the baseline diesel-only fuelling. For this strategy, co-axial injector design parameters [diesel's nozzle diameters (HDD) = 0.2 mm, number of nozzles for diesel (NHD) = 4, methanol nozzle diameters (HDM) = 0.35, number of nozzles for methanol (NHM) = 9)] exhibited promising results. Overall, the first injection strategy emerged as the best for direct methanol injection in the locomotive engine at all engine loads. The main finding of this study was that since methanol had a higher latent heat of vaporization, it should not be injected too late after the diesel pilot injection. This means that methanol must be injected in a sufficiently hot environment to easily vaporize it to ensure its participation in combustion without struggling for evaporation due to the colder in-cylinder environment. The methanol showed relatively lower environmental impact in all three strategies by significantly reducing the NOx emissions. NOx control is a major challenge for the surface transport industry. It could be resolved using methanol, which may expedite its use in internal combustion engines (ICEs), cleaning up the combustion engine based transportation. This simulation study demonstrated that petroleum usage and its negative environmental impact could be reduced by using cleaner/greener methanol.

Effect of cetane coupled injection parameters on diesel engine combustion and emissions

Experiments on the effects of different cetane coupled injection parameters on diesel engine combustion and emissions were conducted on a supercharged 4-cylinder direct injection diesel engine. The results showed that with the increase of cetane number (CN), the peak in-cylinder pressure and heat release rate of fuel decrease, the coupling injection pressure increase, CO and HC emissions decrease, NOx emissions increase, the number concentration and total mass of particulate matter (PM) decrease. As the CN increases, the peak in-cylinder pressure decreases, the coupling injection timing is delayed, the peak heat release rate increases, brake thermal efficiency (BTE) decrease, brake specific fuel consumption (BSFC) increases, CO and HC emissions increase, NOx emissions decrease, and the number concentration and total mass of PM increases. Fuel characteristics and injection timing significantly influence ignition delay time and combustion duration, where CN = 53.9 fuel has no pre-injection to release heat at different injection timing, which has a more substantial impact on in-cylinder pressure and heat release rate.

Performance, combustion and emission characteristics of the CI engine fueled with Botryococcus braunii microalgae with addition of TiO2 nanoparticle

Production of biofuels from the green synthesis considered to be the promising source of the energy to replace the conventional fuels. Further the usage of the biofuels in the optimized ratio will effectively reduce the environmental concerns and the reduce the greenhouse gas emission. In this study, the impact of the Botryococcus braunii microalgae along with the diesel was examined. From the previous work it is understood that, usage of the Botryococcus braunii in the diesel affects the combustion and performance characteristics. To avoid the shortcomings, the nanoparticles TiO2 (50 ppm) were dispersed in the biodiesel blends by sonication method. The test blends such as D100 (100% diesel), B100 (neat microalgae oil), B10 (20% microalgae + 80% diesel), B10T (20% microalgae + 80% diesel), B30 (30% microalgae + 70% diesel) and B30 (30% microalgae + 70% diesel) were tested at engine loads of 0%, 25%, 50%, 75% and 100%. Individual blends were tested for brake thermal efficiency, brake specific fuel consumption, indicated thermal efficient, cylinder pressure and emission of NO, HC, CO and CO2. Based on the findings, addition of the microalgae blends with the nanoparticles enhances the BTE by 5% and 3% for BT20 and BT30, respectively, compared to neat diesel. Further, the BSFC was precisely reduced for B30 compared to D100 and B20 due to the viscosity of the blends. The role of the mixed fuel addition along with nanoparticles increases the cylinder pressure and heat release rate. With regard to emission, the CO, HC and CO2 reported significant drop in the emissions. However, NOx emissions remain to be high despite the engine speed for the blends B30.

Evaluation of oxidation stability and engine behaviors operated by Prosopis juliflora biodiesel/diesel fuel blends with presence of synthetic antioxidant

This experimental study focuses on analyzing the oxidation stability, engine performance, and combustion characteristics of Prosopis juliflora biodiesel blended with synthetic antioxidants. In the first stage, four synthetic antioxidants such as Butylated Hydroxy Toluene, Propyl Gallate, Pyrogallol, Tert-Butyl-Hydroquinone (TBHQ) were selected to evaluate their oxidation stability. Resultantly, TBHQ was the best synthetic antioxidant with the highest induction period, corresponding to 10.19 h, among the above-mentioned synthetic antioxidants while it was added to the B20 blend (20% Prosopis juliflora biodiesel/80% diesel fuel). In the second stage, different concentrations of TBHQ (500, 1000, and 1500 ppm) were added to B20 sample for the test of performane, combustion, and emission characteristics of a 4-stroke diesel engine. Indeed, adding TBHQ to the B20 sample increased brake thermal efficiency and emissions of CO and HC, while it reduced brake-specific fuel consumption and emissions of NOx and CO2. Furthermore, it could be observed a decrease in peaks of in-cylinder pressure and heat release rate, and an increase in mass fraction burned as adding TBHQ. In general, the use of TBHQ antioxidant-included biodiesel for diesel engines could improve engine performance and emission, and enhance the fuel' oxidation stability.

Investigations of combustion, performance, and emission characteristics in a diesel engine fueled with Prunus domestica methyl ester and n‐butanol blends

AbstractThe chief objective of this study is to utilize non‐edible, carbon‐rich oil derived from Prunus domestica seeds as blended fuel. The combustion efficiency of derived blends shall further be enhanced by blending higher alcohol into biodiesel/diesel blends. This work details the impact of effectively utilizing waste and non‐edible oil to replace fossil fuels partially. In this study, the P. domestica is trans‐esterified to methyl ester and blended with diesel at 20%. Further to enhance the ignition nature, butanol, higher alcohol, is blended to P. domestica biodiesel/diesel blends at 5% and 10%. The ignition pattern of the modified fuels is extensively studied and compared with diesel in a stationary research diesel engine. This study involves four fuel samples, namely, neat P. domestica methyl ester and is termed PDME. 20% of PDME is blended with 80% diesel is referred to as PDME20. 20% of PDME with 5% n‐butanol and 75% diesel is termed PDME20Bu5D75, 20% of PDME with 10% n‐butanol and 70% diesel is termed as PDME20Bu10D70 and diesel. Addition of PDME and butanol at different blends found miscible with diesel. PDME and butanol provided a suitable time for reaction and mixing, complete combustion, higher O2 content, and rich fuel‐air mixture, resulting in lower emissions than diesel. Further, butanol aided better atomization, effective combustion and resulted in higher efficiency with lower fuel consumption. Adding butanol also lowered the viscosity and improved the mixing process, and produced better in‐cylinder pressure and heat release rate.

Effect of intake port design modifications on diesel engine characteristics fuelled by pine oil-diesel blends

ABSTRACT The effect of the modified intake port with various inclined nozzle angles such as 30°, 60°, and 90° on the diesel engine characteristics when operated with pine oil-diesel blends is investigated. Prior to the engine experimental study, a computational analysis was performed to investigate the impact produced on the flow field parameters of an engine due to modified intake port design. The numerical study revealed increased swirl velocity and turbulence for intake port with a 60° single-pass configuration compared to other design configurations. With evidence of improved swirl velocity and the proposed modified intake port design from the numerical study, an experimental investigation was performed using pine oil blends in the diesel engine with modified intake port configurations. The preliminary engine test findings with standard intake port design indicated that P50 (50% pine oil + 50% diesel) has higher peak engine cylinder pressure and heat release rates than P10 (10% pine oil + 90% diesel). Additionally, the 60° single-pass configuration showed further increase in peak pressure and peak heat release followed by standard and other intake port design configurations. At high load, the P50 blend showed a 12.3% increase in BTE for 60° intake port design configuration in comparison to the standard design configuration. While for the same blend, the engine out emissions like hydrocarbon (HC) and smoke were reduced by about 6.6% and 17.6%, respectively, and nitrogen oxide (NOX) emission was increased by 29% for the 60° single-pass configuration when compared to the standard design configuration. Overall, the intended intake port design modification strategy increased the swirl velocity and turbulence, which improved the air/fuel mixing and combustion. This study identifies 60° single-pass configuration as an optimum design on account of the aforementioned improved engine combustion, performance, and emissions.

Towards improved performance and lower exhaust emissions using exhaust gas recirculation coupled compression ignition engine fuelled with nanofuel blends

ABSTRACT Emission standards are becoming increasingly stringent. When it comes to diesel engine exhaust emissions, nitrogen oxides (NOx) and soot emissions need effective control as these emissions have a trade-off connection, making it difficult to achieve the emission regulation. To effectively manage NOx emissions from diesel engines, external exhaust gas recirculation has been implemented. The effects of EGR on the engine characteristics of a single-cylinder diesel engine running on pongamia methyl ester mixed with aluminum oxide nanoparticles are detailed in this work. The pongamia methyl ester was mixed with mineral diesel (25 vol. %). The nanofuel blend was made by mixing aluminum oxide nanoparticles with B25 fuel at a dosage of 100 ppm (B25A100). Experiments with diesel, B25, and B25A100 with various EGR rates were conducted in a compression ignition engine (10–30%). The combined impact of nanoparticles blended B25 with 20% EGR yielded a substantial reduction in NOx by 4.95% compared to B25. In addition, the unburnt hydrocarbon, carbon monoxide, and smoke emissions were found to increase as compared with B25. Arise in brake thermal efficiency of 4.6% was noticed for B25A100 + 20% EGR than that of B25. The brake specific fuel consumption was reduced by 4.23% for B25 blend. With 20% EGR, the in-cylinder pressure and instantaneous heat release rate were reduced. As a result, combining pongamia methyl ester with aluminum oxide nanoparticles and 20% EGR enhances engine performance while reducing emissions.

Effects of different injection strategies on mixing, combustion and emission behavior of gasoline compression ignition (GCI) engines

Gasoline compression ignition (GCI) engines have the advantages of high thermal efficiency and low emissions, but show poor combustion stability under low-load conditions. Adjusting the injection strategy can improve the fuel–air mixing process, which is an effective way to solve the fluctuation of GCI combustion. In this paper, the effects of single injection and pre-main injection strategy on the combustion performance and emission characteristics of GCI engines were investigated using a combination of experiment and simulation. The results showed that advancing the injection timing of the single injection could significantly increase the thermal efficiency and reduce the emissions of carbon monoxide (CO), total hydrocarbons (THC), and soot, but also increase the nitrogen oxide (NOX) emissions due to the rise of peak temperature. Compared with the single-injection strategy, the pre-injection strategy could reduce the overall inhomogeneity in the cylinder and increase the OH radicals before the main injection, thus increasing the in-cylinder pressure and heat release rate, and advancing the combustion phase. Moreover, advancing the main-injection timing (MIT) and increasing the pre-injection ratio (PIR) could increase the flame propagation rate and help reduce combustion instability. Under all pre-injection timing (PIT) conditions, when the PIT = 100CAD BTDC, the inhomogeneity of the mixture was the lowest, thereby reducing the generation of soot precursor A4 and lowering the soot nucleation rate. Meanwhile, higher combustion temperature increased the soot oxidation rate, thus reducing the final soot production. By selecting appropriate PIT, advancing the MIT, and increasing the PIR, the GCI engine can obtain the comprehensive benefits of high thermal efficiency, high combustion stability, and low emissions.

Combined effect of intake angle and chamber structure on flow field and combustion process in a small-scaled rotary engine

This work aims to reveal combined effect of intake angle and chamber structure on flow field, flame propagation, combustion characteristics and pollutants formation of a small-scaled rotary engine by using numerical simulation. For this reason, a three-dimensional dynamic simulation model was established by using a reasonable turbulent model and choosing a reduced reaction kinetic mechanism and was also validated by the experimental data. Simulation results showed that intake angle is more significant to the influence of flame propagation, in-cylinder pressure and heat release rate (HRR) in the front baffle combustion chamber (FBCC) and the rear baffle combustion chamber (RBCC) compared to that in the middle baffle combustion chamber (MBCC), but is an opposite trend for effect of flow field. The differences in the in-cylinder velocity field and turbulent kinetic energy magnitude were the intrinsic mechanism of combined influence of intake angle and chamber structure. Under larger intake angle, for the MBCC and the RBCC, higher pressure, HRR and power output were obtained, meanwhile the decreased HC and CO formations were obtained, while showed a contrary tend for the FBCC. And the amount of HC formation for these three combustion chambers at 15°intake angle is relatively small. To sum up, considering combustion characteristics, engine cooling and pollutants formation, it can be concluded that the combination of 15°intake angle and combustion chamber with a middle baffle was the optimum configuration for a small-scaled RE in engineering application. • The recess shape of rotor and intake angle are optimized. • Intake angle is more significant to the influence of combustion in FBCC and RBCC. • Recess shape plays a more significant role in effect of flow field and combustion. • Larger flow velocity and TKE near the spark plugs improve initial flame development. • The optimal scheme is the combination of 15° intake angle and MBCC or RBCC.

The effects of compression ratio and combustion initiation location on knock emergence by using multiple pressure sensing devices

Knock research is an essential study because knock limits spark-ignition (SI) engine power output, durability, noise, fuel consumption, and emission performance. The thermal efficiency of an engine can be improved by increasing the compression ratio, but at the same time it leads to the possibility of end gas autoignition inside the chamber. The objective of this work was to show the effect of three different compression ratios (CRs) 8.5, 9.5, and 10.5 on the mechanism of knock. In order to achieve this four equispaced spark plugs were fitted around the circumference of a special metal liner to initiate flame fronts from those plugs by firing with different spark approaches (e.g. spark timing, number, and location). In addition, six pressure sensors were installed at various locations to precisely record the autoignition event by monitoring pressure oscillations, combustion characteristics, and knock intensity. In-cylinder pressure and heat release rate (HRR) analyses were applied to distinguish the knocking combustion for the three different CRs. The results showed that a greater number of spark plugs produced more stable combustion even for a delayed spark timing (ST) than a single spark plug, but also increased pressure oscillations, HRR and knock propensity with higher CRs due to an increase in pressure and temperature inside the cylinder. The maximum amplitude of pressure oscillation (MAPO) method was used to determine the knock intensity, and it was observed that at the lowest CR of 8.5 three spark plugs gave higher MAPO values compared to four spark plugs for the same operating conditions. However, four spark plugs instigated higher MAPO values than three spark plugs for the higher CRs of 9.5 and 10.5 because, with the increase of CR and spark plug numbers, the pressure and temperature were increased during the combustion event, which was coupled with the compression effect on the unburned end gas mixture. Additionally, Fast Fourier transform (FFT) and wavelet methods were implemented to observe the frequencies induced during knock. It was found that sparking four plugs provoked various vibration modes in different amplitude ranges with the different CRs.

Effect of hydrogen on compression-ignition (CI) engine fueled with vegetable oil/biodiesel from various feedstocks: A review

Compression ignition (CI) engines used in the transportation sector operates on fossil diesel and is one of the biggest causes of air pollution. Numerous studies were carried out over last two decades to substitute the fossil diesel with biofuels so that the net carbon dioxide (CO2) emission can be minimized. However, the engine performance with these fuel was sub-standard and there were many long-term issues. Therefore, many researchers inducted hydrogen along with the biofuels. The present study gives an outlook on the effect of hydrogen addition with biodiesel/vegetable oil from various sources in CI engine. Engine parameters (brake thermal efficiency, brake specific fuel consumption), combustion parameters (in-cylinder pressure and heat release rate) and emission parameters (unburned hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NOx) and smoke emissions) were evaluated in detail. The results show that hydrogen induction in general improves the engine performance as compared to biodiesel/vegetable oil but it is similar/lower than diesel. Except NOx emissions all other emissions showed a decreasing trend with hydrogen addition. To counter this effect numerous after-treatment systems like selective catalytic reduction (SCR), exhaust gas recirculation (EGR), selective non-catalytic reduction system (SNCR) and non-selective catalytic reduction system (NSCR) were proposed by researchers which were also studied in this review.

Performance of Waste Insulating Mineral Oil-Based Biodiesel in a Direct-Injection CI Engine

Mineral oil has been used as an insulating fluid in the power industry. However, surplus waste oil poses serious environmental threats because of disposal concerns. Waste to biofuel is an excellent way to deal with waste material from various sources. In this study, the trans-esterification method was utilised to convert the waste-insulating mineral oil into a quality bio-fuel. Waste-insulating transformer oil was converted to biodiesel, and it was tested according to ASTM standards. Four different blends of waste-insulating biodiesel with diesel in 25 per cent (WIOBD25), 50 per cent (WIOBD50), 75 per cent (WIOBD75), and 100 per cent fractions (WIOBD100), were used for performance testing in a direct injection compression ignition (DICI) engine. The combustion parameters such as BSFC, EGT, and BTE were evaluated with varying crank angles and constant engine speed. The waste-insulating biodiesel performance results are then compared with diesel fuel. BSFC increased as the biofuel mixture in diesel was raised, and the brake thermal efficiency (BTE) was significantly reduced compared to diesel for all WIOBD diesel mixtures. Due to the combustion process, a high pressure and heat release rate (HRR) were noticed inside the cylinder with the waste-insulating oil-derived biodiesel samples. WIOBD biodiesel blends produced lower levels of hydrocarbon, carbon monoxide, and smoke emissions than diesel fuel, but greater levels of nitrogen oxides (NOx) were produced than diesel fuel. In addition to lower emissions combined with improved engine performance, the WIOBD25 fuel blend has been found to be experimentally optimal for practical application. As a result, the test findings indicated that WIOBD biodiesel might be used as a substitute for conventional diesel fuel.

Combustion, performance, and emission characteristics of diesel engine using oxyhydrogen gas as a fuel additive.

A lot of research is being carried out to reduce the environmental pollution resulting from compression ignition engines. For this, various gaseous fuels are being explored as fuel additives in compression ignition engines. The purpose of this research work is to investigate rarely explored Brown's gas (oxyhydrogen gas) in CI engines to reduce environmental pollution. Brown's gas was produced by electrolysis of distilled water with potassium hydroxide as a catalyst. A common rail direct injection CI engine was used for the present investigation. Detail combustion, performance, and emission analyses were carried out, which is scarcely reported in oxyhydrogen gas fuel investigations in compression ignition engines. Oxyhydrogen was injected at varying flow rates of 200 ml/min, 400 ml/min, 600 ml/min, and 800 ml/min in the intake manifold of the CI engine equipped with an electronically controlled common rail direct injector. The peak pressure and maximum heat release rate increased with the increasing concentration of oxyhydrogen gas. The comparison was made between conventional diesel combustion and oxyhydrogen gas addition of 800 ml/min at 75% load. The reduction in CO and HC emissions was about 37.5% and 17.94% respectively. CO2 and NOx emissions increased by 9.37% and 7.41% respectively. Very low smoke emission of 0.01 to 0.02% was recorded at 800 ml/min oxyhydrogen gas flow rate. Thus, it can be concluded that oxyhydrogen gas provides promising benefits in terms of better combustion and low emissions. However, it is recommended to carry out further research to incorporate the use of this additive in actual automobile applications.

Improved delayed detached eddy simulation of supersonic combustion fueled by liquid kerosene

The purpose of this study is to quantitatively investigate the influence of diffusion characteristics and equivalence ratios (ERs) of gaseous/liquid kerosene on transient combustions in a three-dimensional cavity-based scramjet combustor using Improved Delayed Detached Eddy Simulation (IDDES) with a 19 species and 54 reactions kerosene/air mechanism. Additionally, the similarities and differences between gaseous and liquid kerosene supersonic combustion are identified based on the pressure, mixture fraction, temperature, and heat release rate distributions. The findings indicated that the injection velocity of liquid kerosene is an order of magnitude lower than that of gaseous kerosene; however, the residence time of liquid kerosene in the cavity was amplified by two orders of magnitude. The results also highlighted the substantial differences in the reaction heat release position between gaseous and liquid kerosene combustion. For a combustion process of liquid kerosene at an ER of 0.215, there is no obvious boundary layer separation in the isolator. The combustion process is controlled by the mixing efficiency of the shear layer, and the mode of combustion is cavity shear-layer stabilized combustion. When the ERs are 0.27 and 0.43, the flame propagates upstream of the cavity and forms boundary layer separation and oblique shock waves. Then, the combustion process is controlled by the fuel transportation in the cavity recirculation zone, and the mode of combustion is the cavity recirculation-zone stabilized combustion.

Coupling a Lagrangian–Eulerian Spark-Ignition (LESI) model with LES combustion models for engine simulations

In the United States transportation sector, Light-Duty Vehicles (LDVs) are the largest energy consumers and CO2 emitters. Electrification of LDVs is posed as a potential solution, but SI engines can still contribute to decarbonization. Car manufacturers have turned to unconventional engine operation to increase the efficiency of Spark-Ignition (SI) engines and reduce the carbon emissions of their fleets. Dilute, lean, and stratified-charge engine operation has the potential for engine efficiency improvements at the expense of increased cyclic variability and combustion instability. At such demanding engine conditions, the spark ignition event is key for flame initiation and propagation and for enhanced combustion stability. Reliable and accurate spark ignition models can help design ignition systems that reduce cyclic variability. Multiple computational spark-ignition models exist that perform well under conventional conditions, but the underlying physics needs to be expanded, for unconventional engine operation. In this paper, a hybrid Lagrangian–Eulerian Spark-Ignition (LESI) model is coupled with different turbulent flame propagation models for engine simulations. LESI relies on Lagrangian arc tracking and Eulerian energy deposition. The LESI model is coupled with the Well-Stirred Reactor (WSR), Thickened Flame Model (TFM), and g-equation model and used to simulate several cycles of a Direct-Injection Spark-Ignition (DISI) engine using a commercial Computational Fluid Dynamics (CFD) engine solver. The results showcase the successful coupling of LESI with the combustion models. Global engine metrics, such as pressure and Apparent Heat Release Rate (AHRR), for each simulation setup are compared to experimental engine results, for validation. In addition, results highlight the successful prediction of spark channel movement by comparing simulation images to experimental optical engine images. Finally, the successful coupling of LESI to combustion models, making it a usable model in the engine modeling community, is emphasized and future development details are discussed.

Experimental investigation of the impact ethanol-biodiesel-diesel blended fuels on combustion, emission, and performance of compression ignition diesel engine

This research was directed to reduce the global diesel engine emissions and dependency on finite fossil fuel reserves. The ethanol was blended by weight ratio with commercial “B20” fuel (20% palm oil’s biodiesel and 80% diesel) as B20E5 (95% B20 with 5% ethanol), B20E10 (90% B20 with 10% ethanol) and B20E20 (80% B20 with 20% ethanol). The results of the engine’s performance, combustion, emission, and agglomerate particles size using blended fuels were compared with the results of based commercial B20 fuel. All fuel samples were tested on a four-cylinder direct injection diesel engine at a constant load of 140Nm with engine speeds of 1000RPM, 1500RPM and 2000RPM. When the engine speed increased, the brake-specific fuel consumption decreased, and the brake thermal efficiency increased. The B20E20 shows the highest brake-specific fuel consumption because of the low energy content of the fuel blend and the highest thermal efficiency because of a better combustion process. The ethanol-blended fuels show higher peaks of in-cylinder pressure and heat release rate than the base B20 fuel, with B20E20 as the highest. Ethanol blended fuels have significant advantages in particulate matters reduction, especially in idle engine speed. The blended fuels decreased soot and CO2 emissions and increased NOx emission. The agglomerate particles size distribution was analysed with 100 samples for each fuel by using Scanning Electron Microscopy (SEM) and Image J tools. The average agglomerate particle size of B20, B20E5, B20E10 and B20E20 are 0.253 µm, 0.245 µm, 0.225 µm and 0.187 µm, respectively. As conclusion, adding ethanol to diesel fuel provide strong advantages on soot reduction and higher engine efficiency due to the enrich of fuel oxygen.

Comparative assessment of performance, emissions and combustion characteristics of tire pyrolysis oil-diesel and biodiesel-diesel blends in a common-rail direct injection engine

Alternative fuels have gained attention in diesel engines due to the depletion of fossil fuels, climate change, economic issues, population growth, and energy demand. So, the experimental study was conducted by using the tire pyrolysis oil (TPO), biodiesel and diesel blended fuel to compare the combustion, performance, and emission characteristics in the multi-cylinder high-pressure common-rail diesel engine. The results show that the cylinder pressure and heat release rate of all the tested fuels are comparable, especially at 3500 rpm. The torque, brake power, and brake thermal efficiency of P10 is greater than the B10 and diesel fuel due to its high calorific value and oxygen share. At 3000 rpm, the P10 shows the maximum brake thermal efficiency (BTE) of 27.9%, which is 2.2% and 3.3% higher than the B10 and diesel fuel, respectively. P10 indicates the 4% and 5.64% reduction in brake specific nitrogen oxides (BSNOx) emission at 3500 rpm relative to diesel and B10 fuel, respectively. Meanwhile, the highest reduction of 20.2% in smoke opacity was found using P10 compared to diesel fuel at the engine speed of 2000 rpm. Finally, it is concluded that the P10 is suitable as an alternative fuel for multi-cylinder diesel engine without any modification and in fact most of its combustion, performance and emission characteristics are outperformed the B10 fuel.

Performance evaluation of Nannochloropsis oculate–carbon nanoparticle blend as fuel in compression ignition engine

AbstractIn this study, multiwalled carbon nanotubes (MWCNTs) were used as a property improvers for fuel obtained from Nannochloropsis oculate for application in a compression ignition engine. The engine's performance was monitored in accordance with its newly induced characteristics. The fixed biodiesel ratio was blended with different proportions of MWCNTs. The nanotubes were ultrasonicated with the biodiesel in different doses of 50,75, 100 and 150 ppm, respectively, and the resulting fuels were subjected to performance tests as compared with conventional diesel‐fuel in a Yanmar Model‐TF120M diesel engine. It was observed that cylinder pressure and heat release rates were higher under full load condition as compared with those obtained for the diesel fuel. Furthermore, the results compared favorably for both fuels in terms of combustion, emissions and engine performance. The brake thermal efficiency of the blended fuel improved by 2.72, 2.81, 3.07 and 2.24% for BC‐50, BC‐75, BC‐100 and BC‐150 as compared with that of diesel fuel. The release of CO2, NO x , hydrocarbons and carbon monoxide decreased in favor of the blends. From the analysis, a dosing level of 100 ppm MWCNTs in the biofuel is recommended for best engine performance and combustion, with optimal emission reduction. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Effect of low CeO2 nanoparticles dosage in biodiesel-blends on combustion parameters and toxic pollutants from common-rail diesel engine

The effect of toxic pollutants and combustion parameters from six-cylinder turbocharged common-rail diesel engine fueled with low CeO2 nanoparticles dosage in biodiesel blends were investigated. Experiments were examined with four different test fuels under 50% engine load at a constant speed of 1800 rpm. The results indicated that the B15C15 significantly improves the in-cylinder pressure and heat release rate compared to other test fuels. In comparison with B0, the result showed a significant reduction in CO and HC emissions for biodiesel-CeO2 blend fuels, along with a slight increase in NOx ranges between 2.78% and 19.01%. This reduction in unburned hydrocarbon inhibits the peak changes from nucleation mode to accumulation mode. In the meantime, accumulation mode particles decrease and the peak moves to the small particle size. Besides, B15C15 had a positive impact on organic compounds, which resulted in a 64.7% reduction of PAH emissions compared to B0. Whereas the emission factors of n-alkane such as dodecane, tetradecane and hexadecane, showed a negligible amount. However, the significant reduction of the respective concentration of OC and EC suggests that these compounds are either not formed as readily in combustion, or they are reduced effectively with biodiesel-CeO2 blend fuels.

Experimental investigation on combustion and (regulated and unregulated) emissions performance of a common-rail diesel engine using partially hydrogenated biodiesel-ethanol-diesel ternary blend

Partial hydrogenation can augment the oxidation stability for biodiesel, while its low temperature performance worsens and cetane number excessively increases. Blending ethanol can effectively reconcile it. Therewith partially hydrogenated biodiesel (PHB)-ethanol-diesel ternary blend was established in this study. The performances of combustion, regulated emissions and unregulated emissions of PHB-ethanol-diesel ternary blends and PHB-diesel binary blends were investigated on a turbocharged, 4-cylinder common rail diesel engine operated at various loads of 1800 rpm. It was revealed that no obvious variations on equivalent specific fuel consumptions (ESFCs) occurred between binary blends and ternary blends. Compared to diesel, binary blends possessed lower maximums of cylinder pressure (CP) and heat release rate (HRR) in the main combustion stage, whereas ternary blends exhibited the opposite phenomenon. For the regulated emissions, ternary blends generated higher hydrocarbon (HC) and carbon monoxide (CO) emissions but lower smoke emissions, compared to binary blends. For the unregulated emissions, the higher sulfur dioxide (SO2), formaldehyde (HCHO) and carbon dioxide (CO2) emissions, and lower ethylene (C2H4) and ammonia (NH3) emissions were exhausted from ternary blends in comparison to binary blends. Additionally, the law of nitrogen oxides (NOx) and aromatic hydrocarbon (AHC) emissions between ternary blends and binary blends depended on engine load.