Single-cylinder Engine Research Articles

Novel approaches of charging and compounding a single-cylinder diesel engine

Conventionally, charging the single-cylinder engine by turbocharging or supercharging has always been technically challenging. Turbocharging the single-cylinder engine reduces performance due to higher pumping losses and the phase lag between the intake and exhaust valves. Although employing a supercharger enhances the potential for extracting higher power output, the higher brake specific fuel consumption is a disadvantage due to the power consumed by the supercharger. Furthermore, the energy in the exhaust gases is inevitably discharged into the atmosphere. Hence, single-cylinder engines have been significantly underpowered and under-utilized for several decades. The work explores three novel approaches to charge and compound a commercial single-cylinder diesel engine. Firstly, a novel concept of turbocharging the single-cylinder engine using an exhaust plenum was studied. Then, a novel supercharging and turbo-compounding of the test engine is explored, followed by an impulse turbine compounding. All three novel approaches were simulated with a 1D model developed using the commercial 1D simulation software AVL BOOST. Experiments were carried out on the naturally aspirated, supercharged, and turbocharged single-cylinder engine, while simulated results were used on the impulse turbine. Results showed that with the first novel approach, the turbocharged single-cylinder engine delivered 33% higher brake power output with a 345 basis points (3.45% points) improvement in brake thermal efficiency compared to the base naturally aspirated (NA) engine. With the second approach, the supercharged and impulse turbine compounded engine generated 15 kW of power, 47% higher, with 700 basis points (7% points) of improved brake thermal efficiency compared to the base naturally aspirated (NA) engine. The third novel approach delivered 11% higher engine brake power output with 354 basis points improvement (3.54% points) in brake thermal efficiency compared to the base naturally aspirated (NA) engine. All three novel approaches also delivered reduced emissions levels except for oxides of nitrogen (NOx) emissions.

Strategic optimization of engine performance and emissions with bio-hydrogenated diesel and biodiesel: A RVEA-GRNNs framework

This study investigates the effects of blending bio-hydrogenated diesel and biodiesel on engine performance and emissions across various engine speeds (2000-3000 rpm) and loads (25-90%), addressing the growing demand for sustainable transportation fuels. Using a single-cylinder diesel engine from POLAWAT ENGINE Company Limited, we evaluated different bio-hydrogenated diesel and biodiesel blends, optimizing their composition through the Reference Vector Guided Evolutionary Algorithm with a surrogate objective function via Generalized Regression Neural Networks. Results indicate that engine performance is closely linked to combustion temperature, which significantly affects fuel consumption and thermal efficiency. Bio-hydrogenated diesel demonstrated superior performance compared to conventional diesel, with lower fuel consumption and higher thermal efficiency, attributed to its higher cetane index (78 vs. 56) and heating value (47.02 MJ/kg vs. 43.48 MJ/kg). However, increasing biodiesel content in blends tended to increase fuel consumption and decrease efficiency due to biodiesel's lower heating value (39.62 MJ/kg) and higher viscosity (5.16 cSt vs. 2.58 cSt for bio-hydrogenated diesel). Emission analysis revealed that bio-hydrogenated diesel generally produced lower hydrocarbon, carbon monoxide, and smoke emissions than conventional diesel, though nitrogen oxide emissions were slightly higher. Biodiesel blends often showed increased emissions, particularly at higher blend ratios, due to poor fuel atomization. The Generalized Regression Neural Networks model demonstrated high accuracy in predicting engine performance and emissions, with coefficient of determination (R2) values exceeding 0.98 and mean absolute percentage errors below 5%. Optimization results indicated that bio-hydrogenated diesel ratios centered around 90% provided the best balance of performance and emissions. This research bridges critical gaps in combined bio-hydrogenated diesel and biodiesel usage and artificial intelligence-driven biofuel optimization, providing valuable insights for practical implementation in Thailand's agricultural sector.

Exposure the role of hydrogen with algae spirogyra biodiesel and fuel-borne additive on a diesel engine: An experimental assessment on dual fuel combustion mode

This investigation is focused on the study of the overall performance of a single-cylinder diesel engine with the use of 99.99 % pure elemental hydrogen (H2), as a gaseous fuel and algae Spirogyra biodiesel 30 % (SBD30) with 1.5 % Di-tert Butyl Peroxide (1.5%DTBP) as cetane improver and 2 % Algae Residual Carbon Nanoparticle (2%ARCNP). During the investigation, the hydrogen flow rate was controlled by an electronic gas injector and varied in the range of 5–20 lpm in the increment of 5 lpm. Among the fuel blends SBD30 + 1.5%DTBP+2%ARCNP+15H2 acted as a good combination to reduce ID and CD; and to boost HRR, BTE, and EGT. Additionally, this resulted in a drastic decline in the emission components such as HC, CO, and smoke. However, a surge in NO was observed for all the fuel sampled by the induction of H2. For SBD30 + 1.5%DTBP+2%ARCNP+15H2 a shorter ID and CD were observed at 7.2°CA and 34.5 °CA than diesel respectively at full load. The MCP for SBD30 + 1.5%DTBP+2%ARCNP+15H2 was 81 bar which occurred at 9.2°CA, however, the HRR was 61.3 J/°CA which was 1.2 % lower than that of 20 LPM hydrogen flow rate, at full load respectively. By using hydrogen + DTBP + ARCNP, the BSFC was overall lower by about 22 % and the BTE was improved by about 36.1 %. The CO, HC, and smoke for SBD30 + 1.5%DTBP+2%ARCNP+15H2 was 64.8 %, 38.8 %, and 29.2 % lower than diesel however, the NO emission was 32.6 % higher than diesel at full load respectively.

A comparative study of diesel engine fueled by neem and ethanol biodiesel: performance, emissions, and sustainability assessment

Examining the emission characteristics of compression ignition (CI) engines using neem biodiesel in conjunction with ethanol and different percentages of exhaust gas recirculation (EGR) was the aim of the present research. In this experiment, a four-stroke, air-cooled, single-cylinder diesel engine with a rated power output of 5.2 kW was used to change the EGR percentage from 0% to 20%. Examining engine emission parameters and comparing them to diesel fuel was the aim of the research. The experiment indicates that as the EGR fraction in the fresh mixture rises, nitrogen oxide emissions fall. the most percentage of nitrogen oxide reduction as compared to diesel operating on its own. Using ethanol with varying EGR rates may lower emissions of hydrocarbons and carbon monoxide.

TURBOCHARGING UNIT OF THE FOUR-STROKE ENGINE OF THE FORMULA STUDENT RACING CAR

Justification. In any motorsport competitions, for safety reasons, any restrictions on engines are applied: in terms of power, volume, etc. One type of limiter is an air restrictor, which is a calibrated hole in the intake manifold. The most effective and permitted way to increase the power of an engine with a restrictor is to install a turbocharger unit. The purpose of the work is to conduct research on increasing the power of a single-cylinder, inline 4-stroke engine, with an air intake restrictor, by installing an air boost unit. Materials and methods. The study was performed by modeling the operation of a single-cylinder, inline 4-stroke engine, with an air intake restrictor, and a boost unit. To simplify the calculation, the restrictor was taken as a direct diffuser. The calculation was carried out in the Ricardo WAVE software package, which can perform complex calculations of various intake and exhaust systems, with for mathematical modeling of the operation of a single-cylinder four-stroke gasoline engine. With the help of the developed mathematical model, a simulation of the operation of an engine with a boost unit, with and without a restrictor in the main operating modes was carried out in order to obtain its optimal characteristics. The scientific novelty of the study lies in the selection and optimization of the length of the inlet pipe and the use of a restrictor to improve engine performance. Conclusion. The turbocharging unit system (with a restrictor) of the four-stroke engine of the Formula Student racing car has shown a significant advantage over the atmospheric version of the engine. For example, a turbocharged engine has 31 kW and a torque of 34 Nm, whereas a turbocharged engine shows characteristics of 40 kW and 54 Nm, which gives a significant increase in the dynamics of a racing car. Thus, the installation of a boost unit is able not only to solve the problems associated with the restrictor, but also to significantly improve the key performance of the engine. Keywords: engine turbocharging, restrictor, restrictive nozzle.

Experimental study of combustion and emissions characteristics of low blend ratio of 2-methylfuran/ 2-methyltetrahyrofuran with gasoline in a DISI engine

The nearing depletion of fossil fuels and the possible consequences of its emissions on the global climate has prompted a worldwide probe for their alternatives. 2-methylfuran and 2-methyltetrahydrofuran are considered promising alternative fuels for spark ignition engines. In this study, the combustion and emission characteristics of low blending ratio MF20 (2-methylfuran 20 %, gasoline 80 % by volume) and MTHF20 (2-methyltetrahydrofuran 20 %, gasoline 80 % by volume) were first implemented and compared to neat gasoline in a single-cylinder direct injection spark ignition engine. The combustion performance of the test fuels was analyzed across a range of loads from 3.5 to 8.5 bar indicated mean effective pressure and fuel injection timings between 180 and 280 crank angle degrees before top dead center. Meanwhile, the compositions of the hydrocarbon emissions were experimentally investigated using the Fourier Transform Infrared Spectroscopy technique. Results show that MF20 exhibits advanced spark timing flexibility of 8 and 7 crank angle degrees before top dead center compared to the unleaded gasoline and MTHF20 respectively at the peak load. MTHF20 exhibits the highest maximum cylinder pressure at medium load compared to other fuels but drops sharply at peak load accompany with the audible knock. Additionally, MTHF20 exhibits specific fuel consumption advantage over MF20 across the entire load range. The unburned furan of the total hydrocarbon emissions was recorded to be 3 % of total hydrocarbon emissions. The concept of low blending ratio furan-based fuel proposed could provide a solution for the transition period of carbon neutrality.

Mixing-controlled compression ignition of ethanol using exhaust rebreathe at a low-load operating condition—Single cylinder experiments in a heavy-duty diesel engine

As pollutant emissions regulations in the heavy-duty sector become further stringent, the energy requirements in this sector continue to increase. Due to the high-power density and operating period requirements within this sector, full electrification is challenging. A viable solution to meet the stringent requirements for criteria pollutant and greenhouse gas (GHG) emissions is the use of low carbon renewable fuels. Low carbon renewable fuels are desirable due to their lower carbon content per unit energy compared to conventional fossil diesel fuel. However, implementing some low carbon renewable fuels in the heavy-duty sector poses challenges due to their low reactivity and the prevalent mixing-controlled compression ignition (MCCI) combustion strategy. Because of this, ignition assistance is needed to ignite low reactive renewable fuels in MCCI. This work investigates the use of a variable valve actuation (VVA) strategy, exhaust rebreathe, as an ignition assistance method to ignite pure fuel grade ethanol (E98) in MCCI. Exhaust rebreathe utilizes the hot combustion products from the previous cycle by reinducing the exhaust back into the cylinder during the intake stroke from a secondary exhaust valve event. The reinduction of exhaust into the cylinder increases the in-cylinder bulk gas temperature aiding in the ignitability of the low reactive fuel. The exhaust rebreathe strategy as an ignition assistance method is investigated in this work by conducting single cylinder engine experiments on a heavy-duty diesel engine fueled with E98. Exhaust pressure is varied for the exhaust rebreathe strategy to achieve combustion characteristics with E98 similar to diesel at a low-load, high engine speed operating condition. Additionally, an elevated intake air temperature strategy is implemented to compare to the exhaust rebreathe strategy as another form of ignition assistance with the objective to induce heat in-cylinder prior to combustion without the presence of diluent. Furthermore, zero-dimensional (0D) constant pressure chemical kinetic simulations are conducted to evaluate the most reactive conditions for ethanol to achieve ignition delay times similar to n-heptane. The experimental results demonstrate that at a high speed, low load condition—the elevated intake air temperature strategy with ethanol requires 120°C intake temperature to yield an ignition delay similar to diesel. When accounting for the energy required to heat the intake air, the brake thermal efficiency is 40% lower than the diesel baseline. On the contrary, the exhaust rebreathe strategy with an exhaust pressure of 1.5 bar-a, is able to achieve the same ignition delay with an MCCI combustion process but maintain a brake thermal efficiency within 5% of the baseline diesel engine.

Performance, combustion and emission parameters of Scenedesmus obliquus methyl ester in single-cylinder CI engine: an experimental study

Performance, combustion and emission parameters of Scenedesmus obliquus methyl ester in single-cylinder CI engine: an experimental study

Modeling of Hydrogen Combustion from a 0D/1D Analysis to Complete 3D-CFD Engine Simulations

Hydrogen and its unique properties pose major challenges to the development of innovative combustion engines, while it represents a viable alternative when it is based on renewable energy sources. The present paper deals with the holistic approach of hydrogen combustion modeling from a 0D/1D reactor evaluation with Cantera up to complete engine simulations in the 3D-CFD tool QuickSim. The obtained results are referenced to the current literature and calibrated with experimental data. In particular, the engine simulations are validated against measurements of a single-cylinder research engine, which was specifically adapted for lean hydrogen operation and equipped with port fuel injection and a passive pre-chamber system. Special attention is hereby given to the influence of different engine loads and varying lambda operation. The focus of this work is the complementary numerical investigation of the hydrogen flame speed and its self-ignition resistance under the consideration of various reaction mechanisms. A detailed transfer from laminar propagation under laboratory conditions to turbulent flame development within the single-cylinder engine is hereby carried out. It is found that the relatively simple reaction kinetics of hydrogen can lead to acceptable results for all mechanisms, but there are particular effects with regard to the engine behavior. The laminar flame speed and induction time vary greatly with the inner cylinder conditions and significantly affect the entire engine’s operation. The 3D-CFD environment offers the opportunity to analyze the interactions between mixture formation and combustion progress, which are indispensable to evaluate advanced operating strategies and optimize the performance and efficiency, as well as the reliability, of the engine.

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

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

Evaluation of Fuel Consumption and Exhaust Emissions in a Single Cylinder Four-Stroke Diesel Engine Using Biodiesel Derived from Chicken Waste with Additives

Biodiesel is a renewable, locally generated fuel made from vegetable oils, trans fats, or recycled restaurant grease for use in diesel automobiles and other diesel-powered equipment. The physical qualities of biodiesel are comparable to those of petroleum diesel. Biodiesel is used in compression-ignition engines in the same way as petroleum diesel. Biofuel can be made from biomass, but according to the Indian National Policy on Biofuels, biofuel extraction from edible oils is not permitted because it would result in a massive increase in consumer goods prices and perhaps lead to product scarcity. Hence, there is a need to search for alternative biofuel so that it does not affect our nation's national policy. Recently there has been a drastic increase in the consumption of chicken grown in farms. There is a huge problem in disposing of their waste. One major difficulty in waste treatment is poultry manure, often known as slaughter waste. This waste is sometimes dumped on wastelands, roadsides, and the banks of rivers, lakes, and ponds. This creates more sanitary problems for society. According to polls, poultry feces begin to decompose in around three hours. The odor of butcher's waste causes a lot of pollution in the air, as well as an increase in the density of bacteria in the atmosphere. Measures have been taken by the government for the safe disposal of these wastes. One of the major ways of disposal is to recycle this chicken slaughter waste in a useful manner so that it can serve society in a positive way. This could be done by converting this waste into fuel through various processes such as rendering, hydrolysis, extraction, acid esterification, alkaline transesterification, and finally by the extraction process. This produced fuel could be blended with existing diesel in varying concentrations and used in diesel engine-powered vehicles. In this work, the fuel is extracted from the chicken waste and blended with pure diesel and an Al2O3 additive in various proportions. These combinations are then tested on a single-cylinder diesel engine for fuel consumption and emission analysis. The results exhibited an overall better performance when compared to pure diesel.

Evaluation of Impact of Additive-Blended Biofuels (ABFs) on Single-Cylinder Motorcycle Engines

The elimination of subsidies for conventional gasoline (E0) in Nigeria has led to a surge in fuel prices, prompting researchers to explore alternative automotive biofuels. Among the promising options are additive-blended biofuels, which can be used in spark ignition engines (S.I.E.). However, biofuels have limitations, such as lower energy density, compatibility issues, and potential infrastructure degradation. Additive-blended biofuels (ABFs) represent an advanced technology that can address these shortcomings and enhance the performance of blended biofuels in automotive engines. In this study, additives were prepared and added to ethanol-gasoline blends, which are referred to as additive-blended biofuels (ABFs). E0 and ABFs were then tested in a single-cylinder motorcycle engine on a chassis dynamometer to evaluate the performance and emission characteristics of ABFs at partial and full load respectively. It was found that ABFs exhibited an increase in engine torque (T), brake power (BP) and brake mean effective pressure (BMEP) by 42.3%, 25.2% and 48.3%, respectively over E0. In addition, ABFs showed a 40% reduction in brake specific fuel consumption (BSFC) compared to E0. On the other hand, the emission measurements showed that NOX and HC emissions were reduced by 76 % and 35.3 % respectively for ABFs compared to E0.

RSM Hybrid Modeling of a BSFC for a Single Cylinder Four Stroke CI Engine Fueled with Nano-additives Added to Diesel-biodiesel Fuel Blends

Introduction: The expanding need for fossil fuels emphasizes the necessity to comprehend renewable energy sources. Methods: This study examined the performance of a single-cylinder diesel engine using Jatropha biodiesel and aluminum dioxide—the research aimed to evaluate engine reactivity to compression ratio and load variations. The experiment employed with varitaion compression ratios. Results: This study used the Response Surface Methodology to find the best Brake Specific Fuel Consumption performance indicator location. The researchers used a Central Composite Design setup for analysis. A regression model employing the response surface approach was then created to predict fuel phase-out likelihood. Conclusion: This study examines multiple factors' effects. According to studies, Jatropha biodiesel and its blends may improve engine efficiency and lower brake-specific fuel consumption compared to diesel fuel. Minor input parameter modifications are needed to gain these benefits.

Investigations on animal fat biodiesel selected blend by varying the fuel injection pressures and timings in the four-stroke single cylinder compression ignition engine

In the earlier investigations on the animal fat biodiesel, the authors have found that blend 20 was suitable to run the engine. In the CI engines, operating input parameters, FIPs and FITs, are the significant parameters to improve the engine performance and emission characteristics. Biodiesel was prepared by the transesterification process and blended with 20% diesel fuel to get AFB20 blend and to carried out the experiments by varying the FIPs by 180, 200, 220 and 240 bars and FITs by 19°, 21°, 23°, 25° and 27° bTDCs. The experiments were investigated in the single-cylinder 4S CI engine. In the evaluation, it was found that the FIP of 200 bar and 180 bar consumes 0.96% lower BSFC compared to 240 & 220 bars and exhibits a higher BTE of 2.6%. 1.62% lower EGT was found in 240 bar compared to 180 bar. 0.86% lower UBHC and 24.67% lower smoke emissions were observed in 200 and 240 bars. Lower BSFC was found in the 23° IT and higher BTE was found in 19° IT. Lower EGT and UBHC emissions were found in 19° IT. Lower EGT and CO emissions were found in 19° CA and higher CO emission was found in 23° IT at full load.

A Study of Heat Recovery and Hydrogen Generation Systems for Methanol Engines

Biofuels are the most essential types of alternative fuels, which currently have significant potential to reduce CO2 emissions compared to fossil fuels. Methanol is a more efficient fuel than petrol due to its physicochemical properties, such as a higher latent heat of vaporization, research octane number, and heat of combustion of the fuel–air mixture. Also, biomethanol is cheaper than traditional petrol and diesel fuel for agricultural countries. The authors have proposed a new approach to improve the characteristics and efficiency of methanol diesel engines by using biomethanol mixed with hydrogen instead of pure biomethanol. Using a hydrogen–biomethanol mixture in modern engines is an effective method because hydrogen is a carbon-free, low-ignition, highest-flame-rate, high-octane fuel. A small quantity of hydrogen added to biomethanol and its combustion in an engine with a heat exchanger increases the combustion temperature and heat release, increases engine power, and reduces fuel consumption. This article presents experimental results of methanol combustion and a hydrogen-in-methanol mixture if hydrogen was retained due to the utilization of the heat of the exhaust gases. The tests were carried on a single-cylinder experimental engine with an injection of liquid methanol and gaseous hydrogen mixtures. The experiments showed that green hydrogen generated onboard the car due to the utilization of heat significantly reduced fuel costs of engines of vehicles and technological installations. It was established a hydrogen gaseous mixture addition of up to 5% by mass to methanol requires a corresponding change in the coefficient of excess air to λ = 1.25. Also, using an additional hydrogen mixture requires adjustment at the ignition moment in the direction of its decrease by 4–5 degrees of the engine crankshaft. Hydrogen gas mixture addition reduced methanol consumption, reaching a maximum reduction of 24%. The maximum increase in power was 30.5% based on experimental data. The reduction in the specified fuel consumption, obtained after experimental tests of the methanol research engine on the stand, can be implemented on the vehicle engines and technological installations equipped with an onboard heat recovery system. Such a system, due to the utilization of heat and the supply of additional hydrogen, can be implemented for engines that work on any alternative or traditional fuels.

Virtual Development of a Single-Cylinder Hydrogen Opposed Piston Engine

A significant challenge in utilizing hydrogen in conventional internal combustion engines is achieving a balance between NOx emissions and brake power output. A lean premixed charge (Lambda ≈ 2.5) allows for efficient and stable combustion with minimal NOx emissions. However, this comes at the cost of reduced power density due to the higher air requirements of the thermodynamic process. While supercharging can mitigate this drawback, it introduces increased complexity, cost, and size. An intriguing alternative is the 2-stroke cycle, particularly in an opposed piston (OP) configuration. This study presents the virtual development of a single-cylinder 2-stroke OP engine with a total displacement of 0.95 L, designed to deliver 25 kW at 3000 rpm. Thanks to its compact size, high thermal efficiency, robustness, modularity, and low manufacturing cost, this engine is intended for use either as an industrial power unit or in combination with electric motors in hybrid vehicles. The overarching goal of this project is to demonstrate that internal combustion engines can offer a practical and cost-effective alternative to hydrogen fuel cells without significant penalties in terms of efficiency and pollutant emissions. The design of this novel engine started from scratch, and both 1D and 3D CFD simulations were employed, with particular focus on optimizing the cylinder’s geometry and developing an efficient low-pressure injection system. The numerical methodology was based on state-of-the-art commercial codes, in line with established engineering practices. The numerical results indicated that the optimized engine configuration slightly surpasses the target performance, achieving 29 kW at 3000 rpm, while maintaining near-zero NOx emissions (<20 ppm) and high brake thermal efficiency (~40%) over a wide power range. Additionally, the cost of this engine is projected to be lower than an equivalent 4-stroke engine, due to fewer components (e.g., no cylinder head, poppet valves, or camshafts) and a lighter construction.

Enhancing biodiesel engine performance and emission reduction using Fe and Zn coated zeolite catalytic converters

ABSTRACT This study evaluates the performance and emission characteristics of diesel, fish biodiesel (comprising 20% fish oil and 80% diesel), and fish biodiesel using Fe and Zn-coated zeolite catalytic converters. The research aims to mitigate environmental challenges associated with diesel engines by exploring the efficacy of metal-doped zeolite catalysts in reducing harmful emissions. Fish biodiesel was derived from fish waste via transesterification and tested in a single-cylinder diesel engine. Key performance metrics, including Brake Specific Fuel Consumption, Brake Thermal Efficiency, Exhaust Gas Temperature, cylinder pressure, Heat Release Rate, and ignition delay, were measured. Emission characteristics such as carbon monoxide, hydrocarbon, nitrogen oxide, and smoke opacity were also analyzed. Results showed diesel had the lowest Specific fuel consumption, ranging from 730 g/kWh at 25% load to 320 g/kWh at full load. Fish biodiesel exhibited higher Specific fuel consumption, from 770 g/kWh to 350 g/kWh. Regarding emissions, the NOx of the biodiesel increased significantly compared to diesel; the use of a catalytic converter has reduced the NOx emission to a maximum extent of 37.5% at full load for a Fe-coated converter. The Zn-coated converter also improved emissions by up to 33% for NO but was slightly less effective than the Fe-coated converter. The study concludes that Fe-coated zeolite catalytic converters significantly enhance biodiesel-fueled diesel engines’ performance and emission characteristics. Both catalytic converters reduced the smoke emission significantly. These findings highlight the potential for developing more efficient and eco-friendly emission control technologies and promoting using renewable transportation fuels.

Hydrogen-fueled PFI SI engine investigation for near-zero NOx emissions in de-throttled and supercharged ultra-lean burn conditions

This study investigates the efficiency and combustion characteristics of a hydrogen port fuel injection (PFI) spark ignition (SI) engine under various load levels, excess air ratios and intake pressures. Experiments were conducted on a single-cylinder research engine to evaluate the effects of throttle opening and supercharging on pumping work and combustion parameters. The key findings indicate that abnormal combustion events are more closely related to the relative air-fuel ratio (λ) than to load, further limiting load increases during de-throttled operation. Additionally, combustion variability compromised mixture enleanment in both naturally aspirated and supercharged conditions. The gross indicated efficiency was approximately 40.7% across the range of 2.2 < λ < 3.5 with minimal variation. Efficiency gains were linked to reduced heat transfer losses in lean conditions, as validated by computational heat transfer, thermodynamic and fluid dynamic models on Gamma Technologies GT-ISE software. Moreover, nitrogen oxides (NOx) emissions were nearly zero for all test conditions when λ was above 2.2. These findings provide crucial insights into optimizing hydrogen engine performance under various intake pressures, highlighting the potential for achieving high efficiency and low emissions.

Optimization methodology combining Taguchi design and response surface method to maximize a compression ignition engine efficiency fueled with oxygenated synthetic fuel

This research examines the potential of a synthetic e-diesel and oxymethylene dimethyl ether blend in a heavy-duty single-cylinder engine. The main purpose is to find the optimal engine settings that maximize engine efficiency and minimize emissions. As the first step, a methodology was developed and applied to simplify the engine’s map into five characteristic points to be representative of the World Harmonized Transient Cycle, assigning weights to each load region. This simplification reported low error estimations for fuel consumption and NOx emissions over the cycle. After obtaining the five points, a drop-in analysis was assessed, where the fuel was evaluated with the same settings as diesel, revealing more advanced and shorter combustion with great reductions in soot emissions. Then, a group of three air management and three injection parameters was selected for optimization. A novel methodology combining Taguchi Design and Response Surface Methodology is developed and applied to find the best engine settings. By integrating these two methods, the research reduced the number of required experiments if only one method were used and maintained the goal of achieving higher thermal efficiencies with the new fuel blend compared to the diesel baseline. Significant statistical results were obtained in the Taguchi design, revealing the air management factors that most affected the responses; meanwhile, second-order models with high accuracy helped in finding the best injection parameters. Subsequently, the best settings were experimentally evaluated, and optimal conditions determined by the two methods were validated, confirming the effectiveness of the methodology. Optimization results revealed an improvement of around 2% higher efficiencies for the five tested points while achieving important average reductions of 28% less in NOx with additional decreases in CO, HC, and soot levels, all outperforming traditional diesel benchmarks. Finally, a well-to-wheel analysis using the simplified cycle confirmed a substantial reduction in carbon impact when replacing diesel with this alternative fuel. The successful application of this methodology to recalibrate an engine with an alternative fuel blend shows the potential of using these fuels in existing engines and offers a novel methodology that can be escalated and applied under the engine calibration context.

A novel valve strategy for particulate matter reduction in a gasoline direct injection engine operated at cold conditions

In this study, we proposed a novel intake strategy to reduce Particulate matter (PM) emissions from gasoline direct-injection (GDI) engines during cold-start conditions emissions. This strategy is characterized by generating strong intake turbulence and low in-cylinder pressure during fuel injection through delayed intake valve opening, which theoretically promotes fuel atomization and fuel-air mixture, thereby suppressing PM formation during combustion. Experiments were conducted on a single-cylinder GDI research engine, operating at 1500 rpm, 3, 6, and 8 bar IMEP, and stoichiometric air-fuel ratio conditions with low coolant and lubricant temperatures to experimentally demonstrate the effectiveness of the proposed valve strategy in reducing PM emissions. Benchmark tests were performed using an intake camshaft with intake valve opening (IVO) at −13 °aTDC and intake valve closing (IVC) at 227 °aTDC. The novel strategy uses an intake camshaft with very late IVO at 66 °aTDC and IVC at 226 °aTDC. Two injection pressures (Pinj = 100/200 bar) were used to evaluate the pressure requirement for achieving low PM emissions with both strategies. Start of injection was swept and optimized to match the valve strategy. The results showed that the novel valve strategy leads to a 50%–90% reduction in particle number and mass emissions in cold-start conditions, and a lower injection pressure requirement to achieve comparable particle number and mass emissions compared with the normal one. For the novel valve strategy, the fuel impingement with early injection timings is largely mitigated, and thus an early injection timing shortly before the IVO is recommended.