Constant Engine Speed Research Articles

Investigating the Combined Impact of Water–Diesel Emulsion and Al2O3 Nanoparticles on the Performance and the Emissions from a Diesel Engine via the Design of Experiment

This study aims to assess the impact of the water ratio and nanoparticle concentration of neat diesel fuel on the performance characteristics of and exhaust gas emissions from diesel engines. The experimental tests were conducted in two stages. In the first stage, the effects of adding water to neat diesel fuel in ratios of 2.5% and 5% on engine performance and emissions characteristics were examined and compared to those of neat diesel at a constant engine speed of 3000 rpm under three different engine loads. A response surface methodology (RSM) based on a central composite design (CCD) was utilized to simulate the design of the experiment. According to the test results, adding water to neat diesel fuel increased the brake-specific fuel consumption and reduced the brake thermal efficiency compared to neat diesel fuel. In the examination of exhaust emissions, hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) in the tested fuel containing 2.5% of water were decreased in comparison to pure diesel fuel by 16.62%, 21.56%, and 60.18%, respectively, on average, through engine loading. In the second stage, due to the trade-off between emissions and performance, the emulsion fuel containing 2.5% of water is chosen as the best emulsion from the previous stage and mixed with aluminum oxide nanoparticles at two dose levels (50 and 100 ppm). With the same engine conditions, the emulsion fuel mixed with 50 ppm of aluminum oxide nanoparticles exhibited the best performance and the lowest emissions compared to the other evaluated fuels. The outcomes of the investigations showed that a low concentration of 50 ppm with a small amount of 11 nm of aluminum oxide nanoparticles combined with a water diesel emulsion is a successful method for improving diesel engine performance while lowering emissions. Additionally, it was found that the mathematical model could accurately predict engine performance parameters and pollution characteristics.

An experimental study of the performance of a CI engine using ethanol as a fuel stabilizer

Ethanol is a promising alternative fuel owing to its renewable bio-based origin and lower carbon content, as well as its ability to significantly reduce particle emissions in diesel engines. To evaluate the particulate matter emissions and performance of ethanol-diesel blends, researchers conducted experiments using mineral blends of 5% and 10% ethanol with 95% and 90% diesel fuel, respectively, as well as biodiesel blends with 25% biodiesel and 75% diesel fuel, and 100% diesel as a baseline. These blends were tested in a CI engine with a constant RPM of 1350 and variable loads from 0.0 to 1.6 at intervals of 0.2 kg-m. The study found that biodiesel blends reduced exhaust particulate emissions compared to diesel fuel, while the brake specific fuel consumption decreased with increasing brake power, and the brake thermal efficiency increased as brake power increased. The sound pressure level was measured from different locations of the engine, and the results indicated that increasing the percentage of biodiesel led to a decrease in the sound pressure level. Overall, the study concluded that ethanol-blend fuel improved both brake and engine thermal efficiency while reducing particulate matter emissions. The engine experiments evaluated engine brake torque, braking power, brake specific fuel consumption, brake thermal efficiency, and particulate matter emissions under a variable load and a constant engine speed.

An Assessment of the Development of a Mobile Agricultural Biogas Plant in the Context of a Cogeneration System

This article presents examples of cogeneration systems, which are standard equipment for biogas installations, based on the production of heat and electricity. It has been shown that in the case of microgeneration, ease of servicing and low installation costs are crucial. Characteristic aspects of developing concepts for mobile installations (small scale) that produce biogas, often with a simple container structure that is ready to be located in the economic infrastructure of the agricultural industry, were indicated. Recommendations for the operation of micro-biogas models are presented, which have the greatest impact on the advisability of using agricultural waste for energy purposes. A characteristic farm was selected, which has a substrate necessary for the process of methane fermentation of slurry from pig farming. The cogenerator, which constitutes a potential energy demand from the point of view of Polish agriculture in the context of renewable energy production, was analyzed. The research goal was to adapt the cogenerator to the conditions existing on a farm, which should meet the technical and technological expectations for the process of managing the produced methane with a value of 80% in agricultural biogas. The assessment of the impact of the amount of biogas on the level of CO, NO, NO2 and PM emissions was carried out at a constant engine speed for various load levels; the percentage of biogas was changed from 40 to approximately 70–80%, i.e., until significant knocking combustion was detected in the tested engines. As a result, the existing control and control system for the operation of the cogeneration unit prevents the most effective mode of operation of the research installation as a prosumer micro-installation. When the AG20P biogas unit operated in parallel with the grid with an active power of up to 11.7 kW, the electricity produced by the unit met the adopted assumptions and requirements. What is new in this article is the use of a cogeneration unit that has been adapted to its functionality, taking into account the assessment of the prospects for optimizing the cogeneration system in the context of the use of renewable energy sources as agricultural biogas. The best method was to attempt to determine the operating conditions of the cogenerator to develop the optimization of a biogas cogeneration unit producing electricity and heat in a micro-installation for the needs of an individual farm.

Research on the Performance Parameters of a Compression-Ignition Engine Fueled by Blends of Diesel Fuel, Rapeseed Methyl Ester and Hydrotreated Vegetable Oil

This research compares the air pollution (CO, CO2, HC, NOx, smoke), energy (brake-specific fuel consumption, thermal efficiency) and noise indicators of a compression ignition engine fueled by first-generation biodiesel (rapeseed methyl ester (RME)) and second-generation biodiesel (hydrogenated vegetable oils (HVO)), or conventional (fossil) diesel fuel blends. The concentration of first- and second-generation biodiesel in two-component blends with diesel fuel was up to 15% and 30% (RME15, RME30, HVO15, and HVO30); for comparison, the three-component blend of diesel fuel, HVO and RME (RME15–HVO15) was considered. The fuels’ physical and chemical properties were tested in a specialized laboratory, and the engine load conditions were ensured by the engine brake stand. Referring to ship power plants with constant-speed engines, detailed research was carried out in one speed mode (n = 2000 rpm). Studies have shown that two-component fuel blends with HVO are superior to conventional diesel fuel and two-component blends with RME in almost all cases. The HVO in fuel blends reduced fuel consumption up to 1.8%, while the thermal efficiency was close to that of fossil diesel fuel. In addition, a reduction in pollutants was observed: CO by ~12.5–25.0%; HC by ~5.0–12.0%; NOx by ~6.5%; smokiness by ~11–18% (two-component blend) and up to ~29% (three-component blend). The CO2 and noise characteristics were close to those of fossil diesel fuel; however, the trend of reduced smoke emission was clearly seen. A fundamental obstacle to the wide use of HVO can be seen, however, which is the price, which is 25–90% (depending on the EU country) higher than the price of conventional (fossil) diesel fuel.

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.

Comparative analysis of waste tire pyrolysis oil and gasoline as low reactivity fuel in RCCI engine

ABSTRACT The utilization of alternative fuels in internal combustion engines has gained significant attention due to concerns about energy security and environmental sustainability. Waste tire pyrolysis oil (WTPO) is a potential alternative fuel that can be produced from waste vehicle tires through a pyrolysis process. In this study, the possible use of WTPO in a diesel engine operating under Reactivity Controlled Compression Ignition (RCCI) mode was investigated. In the study, the use of WTPO as a low-reactivity fuel in RCCI engines is examined, highlighting the importance of innovative approaches to alternative fuels with varying reactivity levels for effective combustion control and emission reduction. In the experimental work, WTPO was tested at different energy rates of 15%, 30%, and 45% into the intake port using the PFI system, while conventional diesel fuel was injected directly into the cylinder by the CRDI system. The tests were carried out under different engine load conditions while maintaining a constant engine speed of 2400 rpm. The performance, combustion, and emission characteristics of the engine were analyzed and compared between WTPO and conventional gasoline fuel as LRF. The study results show that using WTPO in RCCI operation with sustainable ringing intensity leads to significant increases in Brake Thermal Efficiency (BTE) compared to gasoline usage, with BTE increments of up to 5%, 3.3%, and 6.3% observed with increasing engine load. Furthermore, WTPO usage in RCCI engines effectively reduced hydrocarbon (HC) emissions, addressing a significant issue, and maintaining the known benefits of reactivity-controlled combustion. These findings suggest that WTPO can be utilized as a viable low-reactivity fuel in RCCI engines with acceptable performance, combustion, and emission characteristics.

Determination of the optimum biogas energy ratio in dual-fuel biodiesel used in cooking oil-biogas operation

ABSTRACT This study aims to examine the effects of biogas input ratio on the engine performance, combustion characteristics, and emissions of dual-fuel mode diesel engines fueled by waste cooking oil biodiesel combined with biogas. The engine test was carried out in dual-fuel mode biodiesel-biogas operation with variations in the methane content of the biogas and biogas energy ratio in excess of 90%. The methane gas content was varied from 40%, 60%, 80%, and 100% with different applied loads. A constant engine speed of 2400 rpm is used for all tests. It has been shown that increasing the methane content of the biogas can improve the brake thermal efficiency, particularly at high loads. A maximum brake thermal efficiency of 29.3% can be achieved on dual fuel with 100% methane gas content. This value has increased by 7.51% compared to biodiesel fuel under the same load conditions. Biogas with 100% methane gas also reaches cylinder pressures of 8.07 MPa and rate of heat release of 35.8 J/deg-1 at high load operation. This study confirmed that the use of biogas with more than 90% biogas energy ratio can be operated in a dual fuel mode. At low and medium loads, nitrous oxide emissions are drastically reduced at biogas energy ratios of up to 90%, 82.8%, and 65.1%, respectively. The study also identified the optimum biogas energy ratio operating range of 60–90% for maximum thermal efficiency and low emissions.

Study on using nano magnesium oxide (MNMgO) nanoparticles as fuel additives in terebinth oil biodiesel blends in a research diesel engine

ABSTRACT In this study, the effect of adding metal nano magnesium oxide (MNMgO) to a diesel-biodiesel blend on combustion and emissions was investigated. Firstly, Gas Chromatography-Mass Spectrometry (GC-MS) was used to determine that the unsaturated fatty acid content of Terebinth oil (TO) was 76.4%. Then, the free fatty acid value (%FFA) of TO was calculated to be 5.8%, indicating that the biodiesel production needed to be carried out in two stages. The conversion of triglycerides to methyl esters was confirmed using Fourier Transform Infrared Spectroscopy (FT-IR) at a wavelength of 1438.8 cm-1. The produced biodiesel and MnMgO were mixed with diesel fuel in certain proportions to prepare experimental fuels. The fuels were tested under variable loads and at a constant engine speed of 1500 rpm. The results obtained show that MNMgO reduced carbon monoxide (CO) emissions by an average of 10.23% and hydrocarbon (HC) emissions by 17.18%, but increased nitrogen oxide (NOx) emissions by 2.21%. Additionally, there was a 1.67% increase in cylinder pressure (%CP) and a 7.82% increase in the net heat release rate (%NHRR), while the mean gas temperature (MGT) value decreased by 0.52%.

THE INFLUENCE OF INTAKE VALVE CLOSE TIMING ON THE ENVIRONMENTAL PERFORMANCE OF A SPARK IGNITION ENGINE USING GASOLINE AND NATURAL GAS

The tightening of environmental requirements has forced car manufacturers to look for various ways to reduce exhaust gas emissions. The existing structural solutions of internal combustion engines allow this type of pollution to be reduced by adjusting the intake valve timing. This is especially relevant when it comes to reducing spark ignition engine emissions when using natural gas as fuel. In this study, a wide range of intake valve timing adjustments from 24° to 54° every six crank angle degrees was taken at a constant engine speed (n = 2500 rpm) and different loads and fixed excess air ratios (λ = 1). The changes in oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), nitrous oxide (NOx), methane (CH4), and propane (C3H8) gas emissions were observed in the aforementioned intake valve timing range.

Effect of diesel injection pressure for enhancing combustion and reducing mechanical vibration and noise emissions in a non-road diesel engine

In this study, the combustion, performance, emissions, noise, and vibration characteristics of a single-cylinder, four-stroke, air-cooled diesel engine used for non-road purposes were investigated by controlling different injection pressures with a common rail fuel injection system. The aim of this study is to enhance the combustion performance and improve the existing noise and vibration levels of this commonly used non-road diesel engine in fields such as agriculture, wetlands, and the construction sector by optimizing the injection pressure. The experiments were conducted under low and medium load conditions and at a constant engine speed. The single-cylinder, non-road engine's fuel injection system was controlled using a common rail fuel delivery system, and four different diesel injection pressures (250, 300, 350, and 400 bar) were utilized. The experimental results have shown that the combustion performance, emissions, noise, and vibration values of the non-road diesel engine improved with an increase in diesel injection pressure (DIP). Increasing DIP led to higher maximum combustion pressures and resulted in reductions of HC, CO, and smoke emissions by up to 25%, 48%, and 59%, respectively. Vibration values also decreased by up to 25%.

Experimental Investigation of Compression Ignition Engine Combustion, Performance, and Emission Characteristics of Ternary Blends with Higher Alcohols (1-Heptanol and n-Octanol)

Concerns about the depletion of petroleum reserves and rising pollution led researchers to search for alternate and environmentally compatible fuels for compression ignition engines. As an excellent alternative fuel additive to biodiesel–diesel blends, higher alcohol exhibits outstanding fuel properties (such as high energy content and cetane number) and can operate in diesel engines without requiring engine changes. This study focuses on investigating the ternary blends comprising higher alcohols, namely 1-heptanol and n-octanol, in hybrid biodiesel (animal fat oil–rice bran oil–cottonseed oil) and diesel on compression ignition engine characteristics. The performance, combustion, and emissions of a diesel engine fuelled with mono (D100), binary (B20), and ternary fuel blends (B20H10, B20H20, B20O10, and B20O20) were analysed at a constant engine speed of 1500 rpm. The test fuels met the American Society for Testing and Materials standards for fuel properties and exhibited stable behaviour during testing. Experimental results showed that at 100% load, the least brake-specific fuel consumptions for diesel fuel, B20, B20H10, B20H20, B20O10, and B20O20 were 254.1 g/kWh, 302.14 g/kWh, 281.25 g/kWh, 310.94 g/kWh, 292.8 g/kWh, and 313.80 g/kWh, respectively. Meanwhile, the maximum brake thermal efficiency values were obtained as 38.65%, 37.01%, 37.76%, 36.84%, 37.12%, and 36.38%, respectively. At 100% load, the peak heat release rates for diesel, B20, B20H10, B20H20, B20O10, and B20O20 were found to be 64.65 J/deg, 59.07 J/deg, 62.34 J/deg, 56.12 J/deg, 57.95 J/deg, and 51.9 J/deg, respectively. The addition of 1-heptanol and n-octanol as oxygenated additives into the ternary blend resulted in decreased carbon monoxide and unburned hydrocarbon emissions while increasing carbon dioxide and nitrous oxide emissions compared to diesel fuel. Overall, the study concludes that ternary blends with 1-heptanol and n-octanol as additives improve performance and combustion behaviour and reduce exhaust emissions compared to binary blends.

Development and analysis of the loading characteristic of accumulate fuel injection system Common Rail of the engine 50 RT-flex

The object of research are hydrodynamical processes in fuel delivery system of marine diesel engine of type RT-flex with accumulate fuel injection system of type Common Rail. The problem, being solved, is maintenance of an effective operation of the specified diesel engines due to perfection work of their fuel equipment. The results of simulation modeling of the injection process by accumulator fuel delivery system Common Rail of the 50RT-flex engine are presented. On the basis of the functional diagram of system, a calculation model has been compiled that provides a description of the operation of the systems main blocks. The load characteristic of the fuel equipment is built in the traditional version – the dependence of the fuel delivery parameters from the engine load at a constant speed. For the system under consideration, the control element is the valve assembly connecting the injection control unit (ICU) with injectors. The parameters of the load characteristic in this study are modes with a constant engine speed n=124 rpm and a change in the opening angle of the control valve in the range – jv=6.6–14.4 °CA. The parameters of the devices that largely determine the characteristics of the fuel delivery and the quality of the working processes of a diesel engine are considered in more details. Such an element of the system is ICU, the working body of which is the dosing piston. The main parameters of its operation when delivering fuel are the magnitude and speed of the stroke. For the load characteristics in the accepted range of the valve control valve opening angle jv from 6.6 to 14.4 °CA (2.18 times), the piston stroke was hp=4.29–8.61 mm (2.0 more). In this case, the dependence of hp on jv is linear. Area of use of the data received during research, ship crews and the shore services providing operation of vessels are. A material is applied in process of high school and is already used in various educational forms. The given researches are useful to developers and builders of marine diesel engines of a considered class.

KINERJA DAN EMISI MESIN DIESEL 1 SILINDER BERBAHAN BAKAR CAMPURAN BIODIESEL NYAMPLUNG DAN ETANOL

Research has been carried out on the effect of biodiesel and ethanol fuel mixtures on diesel engine performance and emissions. Ethanol (C2H5OH) is a type of alcohol that can improve the characteristics of biodiesel. The effect of ethanol on engine performance was investigated by adding B30 (a mixture of 30% nyamplung biodiesel (calophyllum inophyllum) and 70% petrodiesel). The concentration of ethanol added to B30 is 10% v/v which is called the B30E10 mixture. The composition of the fuel mixture is B0 (petrodiesel), B30, B30E10 and Pertadex. The research was conducted on a single cylinder four stroke diesel engine with a natural air system and coupled to a generator that functions as a dynamometer. Three times the test was carried out for each load applied to the engine varying from 0, 200, 400, and 600 W at a constant rotation speed of 1700 rpm. The research results that the constant engine speed method and variations in lamp load produce torque values (Nm) and effective power (kW) which tend to be the same between fuels, this happens because it is influenced by the governor mechanism. The highest fuel consumption occurred at the addition of 10% ethanol (B30E10). The lowest thermal efficiency occurs in B30E10. Exhaust emissions of carbon monoxide decreased with the addition of 10% ethanol.

Evaluation of detailed combustion, energy and exergy analysis on ethanol-gasoline and methanol-gasoline blends of a spark ignition engine

This study discusses the combustion behaviour of an SI engine and evaluates the engine's thermodynamic performance through energy and exergy analysis. The test results compared the fuels obtained by adding small amounts of ethanol (and equal amounts of methanol) to gasoline with each other and with gasoline as the reference fuel. The study was conducted at a constant engine speed and five different engine loads (2, 2.5, 3, 3.5, and 4 Nm). Upon examining the study results, it was observed that the addition of ethanol and methanol to gasoline increased the maximum in-cylinder pressure. While the gasoline-alcohol mixtures relatively reduced the average in-cylinder gas temperature, the pressure increase rates significantly increased. It was observed that the volumetric addition of ethanol/methanol to gasoline had a relatively decreasing effect on thermal and exergetic efficiency values.

Synthesis of spirulina microalgae biodiesel, and experimental research of its effects on compression ignition engine responses with iron II-III oxide (Fe3O4) nanoparticle supplementation

The raw material from which biodiesel is produced, the pioneer of alternative fuels in compression ignition engines, has increased importance in recent years. Third-generation biodiesels, which do not harm the food chain and environment, have become popular in recent years. In this study, fuel mixtures were obtained by mixing biodiesel produced from spirulina microalgae, the third-generation biodiesel type, with diesel and iron II-III oxide (Fe3O4) at different concentrations. Microalgae biodiesel (MAB) was mixed with diesel at two different percentages (10% and 20%), and three diverse quantities of Fe3O4 (25, 50, and 75 ppm) were added to 20MAB80D. Since the effects of the fuel mixture containing 20% MAB on the engine response are more optimistic, nanoparticles were added to the fuel containing 20% MAB. These fuel blends were evaluated under various engine loads (from 25% to 100%) at a constant engine speed (1500 rpm), and a compression ratio (15.5:1). Brake thermal efficiency (BTHE) and brake mean effective pressure (BMEP) improved with the addition of both MAB and Fe3O4. Compared to diesel (D100), the highest increases were achieved with 20MAB80D75IO fuel, with an average of 28.64% and 13.18%, respectively. With the 20MAB80D, these increases averaged 12.85% and 3.85%, respectively. On the other hand, brake-specific fuel consumption (BSFC) response increased with MAB and decreased with Fe3O4. With 20MAB80D75IO fuel, it showed an average decrease of 19.02% compared to BSFC diesel. With the 20MAB80D, there was an average increase of 11.31%. MAB and Fe3O4 contributed to reducing carbon monoxide (CO) and hydrocarbon (HC) emissions, which are products of incomplete combustion. With 20MAB80D75IO fuel, an average of 24.21% and 57.36% reductions were achieved, respectively, compared to D100. With the 20MAB80D, there was an average of 20.14% and 22.62% reductions, respectively. Conversely, NOx produced by 20MAB80D75IO was 11.63% higher than D100, while NOx produced by 20MAB80D was 3.83% higher. In conclusion, the experimental data obtained using Fe3O4 nanoparticles added to improve engine responses by improving the properties of MAB produced as third-generation biofuels revealed that MAB would be an excellent alternative fuel and Fe3O4 was a suitable additive.

Twin injector biogas diesel RCCI mode-an effective means to reduce NOx emissions without penalty in fuel consumption

The RCCI (Reactivity Controlled Charge Compression Ignition) mode of operation of an IC engine using biogas and diesel as fuels has the potential to offer high efficiencies and low NOx and soot emissions. One of the drawbacks while converting conventional diesel engines to run in this mode is the wall wetting of the diesel that has to be injected early in the compression stroke. This leads to high THC emissions and lubricating oil dilution. In this work a twin cylinder turbocharged, common rail diesel engine was modified to accommodate a newly developed Narrow angle Injector (NI) for early injection of diesel without wall wetting, along with the existing Wide angle Injector (WI). Biogas was also injected into the intake manifold and the engine was run in the RCCI mode. The effectiveness of this novel twin injector dual fuel RCCI concept has been experimentally assessed at different biogas energy shares under a BMEP of 3 bar and at a constant engine speed of 1500 rpm. The different biogas – diesel modes considered were the conventional dual fuel mode (CDF), RCCI with the WI alone, RCCI with the NI alone and finally RCCI with the combined NI-WI. In the biogas diesel RCCI mode the use of only the WI resulted in low efficiency, high THC and smoke emissions due to cylinder wall wetting of diesel. Though the use of only NI in this mode could eliminate cylinder wall wetting, the diesel directly hitting the piston bowl resulted in poor performance. However, the combination of NI and WI resulted in high BTE and extremely low levels of NOx emissions and lower THC as compared to the CDF mode. The range of injection timings for the NI was 90° to 45° bTDC while for the WI it was 42° to 4° bTDC when the energy share of biogas was changed. Thus the use of two injectors with wide and narrow injection spray angles for diesel gave enhanced flexibility in operating at widely different injection timings as required in biogas diesel RCCI operation.

Numerical Investigation of a Reactivity-Controlled Compression Ignition Engine Fueled with N-Heptane and Iso-Octane

In this numerical study, the effects of the premixed ratio, intake manifold pressure and intake air temperature on a four-cylinder, four-stroke, direct injection, low-compression-ratio gasoline engine, operated in reactivity-controlled compression ignition (RCCI) combustion mode at a constant engine speed of 1000 rpm, were investigated using Converge CFD software. The results of numerical analyses showed that the maximum in-cylinder pressure and heat release rate (HRR) increased and the combustion phase advanced depending on the rise in both intake manifold pressure and intake air temperature. The CA50 shifted by 18.5 °CA with an increment in the intake air temperature from 60 °C to 100 °C. It was observed that the combustion duration dropped from 44 °CA to 38 °CA upon boosting the intake manifold pressure from 103 kPa to 140 kPa. Moreover, a delay in the combustion phase occurred at a constant intake air temperature with an increasing premixed ratio. The maximum value of in-cylinder pressure was recorded as 36.15 bar (at 11 °CA aTDC) with the use of PRF20. Additionally, as the content of iso-octane in the fuel mixture was increased, combustion delay occurred, and the maximum value of in-cylinder temperature obtained was 11 °CA aTDC using PRF20 fuel at the earliest point. While HC and CO emissions reached the highest values at a 60 °C intake air temperature, NOx and soot emission values were detected at quite low levels at this temperature. The values of all these emissions increased with rising intake manifold pressure and reached their highest values at 140 kPa. In addition, while the highest HC and CO emission values were observed with the use of PRF60 fuel, the results revealed that the control of the combustion phase in the RCCI strategy is notably affected by the premixed ratio, intake manifold pressure and intake air temperature.

Simulation analysis of cycle skipping strategy in SI engine fueled with ethanol gasoline mixture

Researches are carried out with different methods to reduce the emissions emitted by conventional fuel engines. In addition to using alternative fuels, especially ethanol, in gasoline engines, fuel injection, and combustion controls are applied in various strategies. In this study, the effects of various cycle skipping strategies on emissions were analyzed through a numerical model of a single-cylinder naturally aspirated spark ignition (SI) engine. The validated model was fueled with an ethanol gasoline blend with 30% ethanol content. The model engine was operated at partial load and 1500 rpm constant engine speed under Normal (N), 1N1S, 2N1S and 3N1S cycle skip strategies. NOx emission increased with all strategies due to increased in-cylinder temperature with more fuel depletion in ignition cycles. The BSFC decreased by 9.93%, 13.67% and 5.93% in the 1N1S, 2N1S and 3N1S cycle skipping strategies, respectively. CO and HC emissions decreased with all cycle skipping strategies compared to the normal cycle.

Effects of Thermal Barrier Coated Piston on Performance and Combustion Characteristics in Dual-Fuel Common-Rail Diesel Engine

In this study, performance and combustion characteristics of biogas and biogas+hydrogen mixtures were experimentally analysed and compared with baseline diesel fuel in a common-rail diesel engine with and without thermal barrier coated piston. Tests were conducted at three different loads (50 Nm, 75 Nm, and 100 Nm) and a constant speed of 1750 min-1. Engine pistons were coated with Yttria Stabilized Zirconia by atmospheric plasma spray method. Results showed that by replacing the standard pistons with the coated pistons, an increase for diesel, biogas, and hydrogen enriched biogas was respectively defined by 8.1%, 6%, and 23% in cylinder pressure, and 19.8%, 12.6%, and 25% in HRR at medium load. Similarly, there was an increase in range of 1.05-12.8% in gas temperature and 20.5-117.2% in knock intensity by the piston coating. CA10-90 was prolonged between 1-15 oCA with gaseous fuel modes and increased with the engine load. Volumetric efficiency was reduced by 0.1-4% with the gaseous fuel operations, while it was increased by using the coated piston for all fuels. Exhaust gas temperature increased with the gaseous fuels whereas showed discrepancies with the coated piston engine. Dual-fuel mode and coated pis-ton application caused brake specific energy consumption to increase significantly.

The combined effect of EGR and hydrogen addition on a Syzygium cumini (jamun) liquid biofuel engine

Rapid depletion of fossil fuels required the development of alternate and sustainable fuel sources that could replace conventional fuel while having no negative environmental impact. Combining hydrogen induction with biodiesel ensures strict emission standards and lowers energy consumption compared to conventional fuels. In this study, the performance, emissions, and combustion of a CI engine for Syzygiumcumini (B20) were assessed and compared to diesel fuel while using a fixed amount of hydrogen flow rate (6L/m). Throughout the experiment, an exhaust gas recirculation (EGR) technology of 10% and 20% and a constant engine speed of 1500 rpm at varying engine load circumstances were used. When hydrogen is added to B20, it decrease the emissions of carbon monoxide (CO), unburned hydrocarbons (UHC), brake thermal efficiency (BTE), and brake specific energy consumption (BSEC). At maximum load, the use of the EGR system decreased the exhaust gas temperature (EGT) by 13.4% and nitrogen oxide (NOX) emission by 25%, but it had a negative impact on BTE, BSEC, as well as other emission parameters including CO and UHC. Therefore, using hydrogen in dual fuel mode in a CI engine enhances performance and lowers exhaust emissions, while using the EGR approach reduces NOX emissions.