Four-stroke Engine Research Articles

Analyzing the impact of injection timing variations on the performance of multi-cylinder CNG direct injection spark-ignition engine

Abstract Objective: This study investigates the impact of Compressed Natural Gas (CNG) injection timing on the performance of a retrofitted CNG Direct Injection (CNG-DI) engine. The aim is to understand how varying injection timing affects key performance metrics such as torque, power, thermal efficiency, and fuel consumption in CNG-DI engines, providing insights for system optimization.
Methods: A 1298 cc, four-cylinder, four-stroke spark ignition engine with a compression ratio of 9 was retrofitted for CNG-DI operation. Modifications included a redesigned cylinder head for high-pressure injectors, controlled by a programmable gas ECU. The engine was tested with three injection timings: Early Injection (EI) at 230° BTDC, Optimal Injection (OI) at 180° BTDC, and Late Injection (LI) at 130° BTDC. Performance, Emission and Combustion parameters were evaluated across engine speeds from 1000 to 3100 rpm.
Results: Late Injection (LI) timing improved torque, power, BMEP, thermal efficiency, and volumetric efficiency by 4-16% within the 1000-2200 rpm range, attributed to better combustion dynamics. Optimal Injection (OI) timing achieved 4-12% higher performance in the 2500-2800 rpm range due to improved mixture formation. Early Injection (EI) timing resulted in 3-8% improvements at speeds above 2800 rpm, driven by faster combustion and increased peak power.
Conclusion: This study highlights the crucial role of injection timing in optimizing CNG-DI engine performance: Late Injection improves fuel efficiency at lower speeds, Optimal Injection enhances thermal efficiency at mid-range RPMs, and Early Injection maximizes power at higher RPMs. However, the study is limited by its focus on a single engine configuration and does not consider emissions or Life Cycle Assessment (LCA). Future research should investigate the environmental impact of injection timing through LCA and assess the long-term durability of engine performance.

Improvement of Engine Combustion and Emission Characteristics by Fuel Property Modulation

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

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.

Optimization of bio-oil blends in gasoline engines for enhanced efficiency and emissions reduction: A response surface methodology approach

The escalating global demand for energy, coupled with growing environmental concerns, necessitates the exploration of cleaner fuel alternatives. Bio-oil, characterized by its renewability and potential to mitigate emissions, has emerged as a viable candidate. This study focuses on optimizing bio-oil concentrations in gasoline engines to enhance operational performance while reducing pollutant emissions. Employing Response Surface Methodology (RSM), the investigation evaluates the effects of varying bio-oil-gasoline blends on engine performance metrics, fuel consumption, and exhaust emissions. Experiments were conducted using a single-cylinder, four-stroke gasoline engine with bio-oil concentrations of 5 %, 10 %, and 15 %. The results identified an optimal bio-oil concentration of 9–10 % and an injection pressure range of 220–230 bar Under these conditions, the Brake Thermal Efficiency (BTE) increased by 31.1 %, and the Brake Specific Fuel Consumption (BSFC) was reduced to 274.4 g/kWh, indicating enhanced fuel efficiency. Emissions analysis demonstrated a 45 % reduction in carbon monoxide (CO) and a 50 % decrease in hydrocarbon (HC) emissions at a bio-oil concentration of 10 %, with nitrogen oxide (NOx) emissions controlled below 110 ppm at higher bio-oil levels. These findings suggest that the optimized bio-oil blend significantly improves engine efficiency while minimizing environmental impact, positioning bio-oil as a promising solution for cleaner and more sustainable energy production.

Experimental investigation of Gyroid recuperator performance integrated with internal combustion engine

The recuperator has the potential to enhance engine performance, reduce fuel consumption, and lower pollutant emissions, making it a promising technology for promoting environmental sustainability. This study investigates the impact of a Gyroid recuperator on the performance of a four-stroke internal combustion engine. Experimental analyses compared engine performance at various set points of rotational speeds before and after recuperator installation. The results validate the effectiveness of the Gyroid recuperator in recovering waste heat, thereby leading to improvements in fuel efficiency. The optimal performance, characterized by an 832.31 J/s increase in recovered combustion heat energy, was observed at 7000 RPM. Additionally, the Gyroid recuperator achieved a maximum overall heat transfer coefficient of 7.9215 W/m2 K at 8000 RPM. The performance of the Gyroid recuperator was further analyzed using the log mean temperature difference method, which yielded a peak value of 114.4 °C at 7000 RPM. The effectiveness-number of transfer units’ method was also employed to assess its effectiveness. These results show that the recuperator can efficiently transmit and recover heat under certain working circumstances. The analysis suggests higher heat energy losses at lower speeds than high speeds, indicating a more efficient energy conversion process at higher engine speeds. The possibilities of the Gyroid recuperator to improve engine performance and its suitability for internal combustion engines are highlighted in this study. This technology offers a promising solution for improving vehicle efficiency and promoting environmental sustainability.

PERFORMANCE ANALYSIS OF ELECTROMAGNETIC VIBRATION ENERGY HARVESTING DUE TO DIFFERENT VIBRATION SOURCES

As industry requires more real-time monitoring and interconnected systems, the need for wireless sensors will increase. Vibration Energy Harvesting (VEH) has played an important role as an alternative energy source to provide power to wireless sensors. In this paper we report the analysis of an electromagnetic energy harvester driven by vibrating plate. An experimental method where energy sources originating from vibrating mechanical machines were used. Mechanical machines such as milling machines, dynamic rotors, and four-stroke engines were implemented to prove the performance of the device. where the output signal from the vibration source is measured using a CF-3600 FFT analyzer, while the output signal from the electromagnet is measured using an oscilloscope (Hantek 6022BE). This paper has discussed several sources of vibration originating from industrial equipment with a vibration source frequency of around 10 to 100 Hz. The findings show that the voltage produced by an electromagnetic energy harvester is 130 mV, 120 mV, and 30 mV on a milling machine, dynamic rotor, and four-stroke engine. Additionally, the results contribute to the optimization of vibration energy harvesting parameters, facilitating the maximization of energy extraction in diverse applications.

Analysis of the Principle and Applications of Four-stroke Engines in Transportation

Abstract. Four-stroke engines a type of internal combustion engine (IC engine) that can turn the heat provided from the fuel to work, and they are mainly classified as two groups, which are gasoline engines and diesel engines. Four-stroke engines can be applied to high power machines because of its high thermal efficiency. In four-stroke engines, the piston reaches the dead center four times in the cylinder to complete a cycle. This cycle includes the taking in of gas, the compression, the ignition, the expansion and the exhaustion of gas. In gasoline engine, this cycle is called the Otto cycle, and in diesel engine, this cycle is called the Diesel cycle. The greatest difference between these two engines is that they burn different types of fuel. In that way, the procedure of converting the heat to work is different. To help this cycle performs better economically and more efficiently, additional attachments such as hybrid engine and computer assistance are used. This research summarizes and analyses the application of four-stroke engines in land transportation, in aviation and in marine transportation, and this article gives a possible prediction to the future trend of the technology advancements of engines in transportation based on the analyses.

Investigating the potential of plastic pyrolysis oil-diesel blends in diesel engine: Performance, emissions, thermodynamics and sustainability analysis

The abrupt rise in demand for conventional fuels has become a major cause for concern despite their increasing depletion. That's why the pyrolysis process to make plastic pyrolysis oil (PPO), can be used to prepare fuel as an alternative fuel. The batch pyrolysis reactor was fabricated to produce plastic pyrolysis oil (PPO) from locally sourced grocery bags made of high-density polyethylene (HDPE). The purpose of this study was to thoroughly analyze the performance and emission characteristics of an engine running on up to 15 % PPO-diesel blended fuel. Then, the experimental data obtained from a single-cylinder, four-stroke engine with five distinct speeds ranging from 1000 to 3500 rpm were utilized to undertake energy, exergy, and sustainability assessments. The results showed that DPO5 had a maximum brake power of 1.92 kW at 2500 rpm. At 3500 rpm, the engine achieved a thermal efficiency of 47.44 % for diesel and 51.6 % for DPO5 blended fuel. Furthermore, DPO15 produced the least quantity of CO2 at all engine speeds. DPO5 has the highest sustainability index, 1.52 at 2500 rpm. As a result, our research found that a low-level PPO-diesel fuel blend may be effectively injected into diesel engines without requiring any modifications.

Experimental Assessment of a Refrigeration System Powered by a Gasoline Engine Utilizing GasolineBioethanol Mixture

Dependable refrigeration is essential for vaccine preservation, especially in distant and resourcelimited areas with unstable electrical supply. Gasoline-powered refrigeration systems present a viable option to electric-powered units; however, their efficacy and environmental consequences necessitate comprehensive assessment. This study investigated the experimental evaluation of a gasoline-powered refrigeration system featuring a micro-cooling compartment specifically intended for vaccine storage. Gasoline-bioethanol blends (E0, E5, E10, and E15) were evaluated in a fourstroke spark-ignition engine to enhance fuel economy and environmental sustainability. The physicochemical characteristics of these blends, such as pour point, octane number, cetane number, viscosity, density, carbon residue, and heating values, were examined to ascertain the optimal fuel composition. The system's effectiveness was estimated using COP. The findings reveal that the E10 gasolinebioethanol blend exhibited significant performance attributes, featuring appropriate octane ratings, viscosity, and density, alongside less carbon residue of 74% and an improved heating value of 410 MJ/kg and COP value of 12%. The employment of the E10 blend significantly reduced CO₂ emissions and enhanced engine performance, rendering it a viable fuel option for gasolinepowered refrigeration systems in this context. This study emphasizes the promise of E10 as a more environmentally friendly and efficient fuel option for gasoline-powered refrigeration systems, enhancing engine performance and aiding in the reduction of carbon emissions. This research provides significant insights into sustainable refrigeration options for vaccine preservation in environments where conventional refrigeration is impractical, hence enhancing public health in neglected communities.

Сучасні тенденції розвитку двигунів безпілотних літальних апаратів

The subject of this study is the current state and prospects for the development of the market for unmanned aerial vehicles (UAVs) and power plants. The purpose of this work was to identify trends in the development of UAV engines of various classes. Task: collection, systematization, and analysis of information on the most common engines of reconnaissance and strike UAVs of the operational-tactical level, as well as UAVs of the "barrage ammunition" class. This article provides a brief description of various types of UAV power plants, and their main advantages and disadvantages are given, which are often decisive when choosing the type of power plant for a specific UAV. It was found that a power plant with an internal combustion engine (ICE) is best suited for use in medium- and long-range UAVs.This study demonstrated that four-stroke internal combustion engines are most commonly used in reconnaissance-strike UAVs at both operational and tactical levels. The features of the design and characteristics of four-stroke internal combustion engines, which have become the most widely used UAVs, are described. It was determined that the introduction of turbocharging or increasing the pressure is the main means of forcing four-stroke internal combustion engines, which makes it possible to simultaneously achieve high specific power and high brake efficiency of the engine over a wide range of altitudes during its operation. It is shown that one of the most important tasks for a long-range UAV engine is to reduce the specific brake fuel consumption. Thus, there is a tendency to promote the use of high-powered aviation diesels in long-range UAVs. It was determined that the main requirements for UAV engines of the "barrage ammunition" class are high specific power, low cost and adaptability to mass production. This study shows that gasoline two-stroke internal combustion engines with crank-chamber scavenging are extremely widespread in UAVs of the "barrage ammunition" class. The design features and characteristics of UAV two-stroke internal combustion engines are described. The main means of ensuring high specific power of such two-stroke internal combustion engines are increasing the engine RPM, optimizing gas exchange processes, and reducing the weight of the construction by using new materials. Conclusion. The results show that depending on the UAV type, the set of engine requirements can vary significantly. Modern trends in the development of UAV engines of various classes have been determined. Potentially promising directions for increasing the efficiency of engines and for comprehensive improvement of their indicators and characteristics have been determined.

The Influence of the Intake Geometry on the Performance of a Four-Stroke SI Engine for Aeronautical Applications

In this work, the influence of plenum and port geometry on the performance of the intake process in a four-stroke spark ignition engine for ultralight aircraft applications is analyzed. Three intake systems are considered: the so-called “standard plenum”, with a relatively small plenum volume, the “V1 plenum”, with a larger plenum volume, and the “standard plenum” equipped with a large curvature manifold called the “G2 port”. Both measurements and 3D CFD simulations, by using Ansys® Academic Fluent, Release 20.2, are performed to characterize and analyze the steady-flow field in the intake system for selected valve lifts. The experimental data and the numerical results are in excellent agreement with each other. The results show that at the maximum valve lift, i.e., 12 mm, the V1 plenum allows an increase in the air mass flow rate of 9.1% and 9.4% compared to the standard plenum and the standard plenum with the “G2 port”, respectively. In addition, the volumetric efficiency has been estimated under unsteady-flow conditions for all geometries at relatively high engine rpms. The difference between numerical results and measurements is less than 1% for the standard plenum, thus proving the accuracy of the model, which is then used to study the other configurations. The V1 plenum shows a fairly constant volumetric efficiency as the engine speed increases, although such an efficiency is lower than that of the other two geometries considered in this work. Specifically, the use of the “G2 port” leads to an increase of 1.5% in terms of volumetric efficiency with respect to the configuration with the original manifold. Furthermore, for the “G2 port” configuration, higher turbulent kinetic energy and higher swirl and tumble ratios are observed. This is expected to result in an improvement of air–fuel mixing and flame propagation.

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.

Equivalent Simulation Study of Delta-Rotor Engine

The mechanical structure, movement mode, and combustion process of a triangular rotor engine differ from those of a conventional engine with a crank connecting rod mechanism as the core. This makes it impossible to directly use existing simulation software to simulate the performance of the entire engine, rendering it difficult to conduct structural evaluation and performance prediction during the engine development stage. Therefore, using existing performance simulation software to establish a performance-equivalent model for a triangular rotor engine is crucial. To solve the above problems, this study proposes a performance-equivalent simulation modelling method for a triangular rotor engine based on a three-dimensional simulation model and the operating principles of the triangular rotor and four-stroke engines. Compared to various performance indicators obtained from the three-dimensional simulation model, the results show that the equivalent model established in this study has sufficient accuracy for key indicators such as the cylinder pressure, cylinder temperature, and in-cylinder quality under various working conditions. This can satisfy the requirements of the complete machine-performance simulation of a triangular rotor engine.

Experimental Investigation on Performance Characteristics o f Diesel Engine Using Various Blended Biodiesels

Objectives: To evaluate the performance characteristics of diesel engines through experimental research with various biodiesel blends. Method: Three types of oils were chosen for this study: waste cooking oil, waste chicken oil, and palm oil. The methyl esters were produced from waste chicken oil (COME), waste cooking oil (WCOME), and palm oil (POME). The test runs were done on a 4.5 kW direct injection, air-cooled, four-stroke, single-cylinder, and constant-speed diesel engine using varied fuel at maximum load. Findings: This study finds performance analysis for a variety of methyl esters and diesel. The Brake Thermal Efficiency (BTE) was found to be: for Diesel (33.36%), POME (30.53%), WCOME (27.5%), COME (25.0%) at rated power (4.5) K.W. The brake thermal efficiency for palm oil methyl esters is similar to the diesel compared to the other methyl esters. Novelty: This research study provides a comparison between the diesel and methyl esters of break thermal efficiency for diesel engines. Keywords: Diesel Engine, Trans esterification, Biodiesels, Performance characteristics

МОДЕЛИРОВАНИЕ ПУСКА ДВС АВТОМОБИЛЯ С БЕССТУПЕНЧАТОЙ КОРОБКОЙ ПЕРЕДАЧ

The aim of the work is to build a computer dynamic model of moving internal combustion engine parts and a continu-ously variable transmission to determine the starting characteristics of the internal combustion engine. The paper objective is to define the characteristics of moving parts of the internal combustion engine and continuously variable transmission when starting the internal combustion engine with an electric starter. The research method is computer modelling of moving internal combustion engine and transmission parts when starting with an electric starter. The novelty of the work lies in building a computer model of moving parts of an internal combustion engine and a contin-uously variable transmission, connected by a torsional vibration damper, considering changes in friction parameters. The results are in developing a computer model to determine the starting characteristics of a four-cylinder in-line four-stroke internal combustion engine with spark ignition and a continuously variable multitronic® 01J transmis-sion. To check the computer model adequacy, the author uses the values of the average friction pressure in accord-ance with GOST R 54120-2010 and empirical data on the unevenness of the angular velocity of the crankshaft. Simu-lating a four-stage start of an internal combustion engine shows that opening the cylinder valves at the 1st stage in-creases the angular velocity of the crankshaft by 4%. Temporary switching on the reverse clutch for 1.4 s reduces the amplitude of angular oscillations of the solar shaft by 2.22 times, eliminates the beating of the contacting gearbox teeth, but slows down the crankshaft speed by 7.6%. After the reverse clutch is turned off, periodic changes in the an-gular velocity of gearbox parts occur.

Evaluating Engine Performance, Emissions, Noise, and Vibration: A Comparative Study of Diesel and Biodiesel Fuel Mixture

This study investigates the performance, emissions, noise, and vibration characteristics of a single-cylinder, air-cooled, four-stroke diesel engine running on pure diesel (D100) and biodiesel blends (B10: 90% diesel, 10% biodiesel; B20: 80% diesel, 20% biodiesel) at 1800 rpm, where the engine delivers maximum torque. Key metrics such as torque, power, brake specific fuel consumption (BSFC), exhaust gas temperature, noise, vibration, and emissions (CO, CO2, HC, O2, NOx, and smoke opacity) were analyzed. The findings indicate that B10 enhances torque, power output, and overall fuel efficiency, especially at low to medium loads, with a significant 17.54% reduction in BSFC compared to D100 at 40% engine load. Vibration levels generally increased with biodiesel addition, while B10 and B20 both reduced smoke opacity, with B20 having a more substantial effect. HC emissions decreased at idle with B10 but increased at higher loads, suggesting more complete combustion with potential thermal stress on engine components. Noise and vibration results were mixed; B20 reduced noise at higher loads but increased vibration. At 100% load, B20 decreased noise by 1.42% compared to D100. Despite benefits such as improved torque and reduced particulate emissions, biodiesel blends, particularly B20, led to increased NOx and CO2 emissions, emphasizing the need for further op-timization of blend formulations and emission control strategies. This study provides valuable insights into the tradeoffs and potential of biodiesel blends as sustainable diesel alternatives.

Comparative analysis of spark ignition engine performance using RON 95 and RON 100 gasoline fuels

Most of the vehicles used by Malaysians have engines that only require petrol RON 95 to power the engine. However, many people claimed that utilising RON 100 instead of RON 95 for their vehicles will improve engine performance. Furthermore, many people speculate that using oil with a low octane level in an engine with low performance will affect the engine's performance. The goal of this research is to analyse and compare the engine performance and emissions on a spark ignition engine using gasoline RON 95 and RON 100. In this study, a single-cylinder four-stroke engine running with RON 95 and RON 100 has been tested on an engine dynamometer to evaluate the brake power, torque, specific fuel consumption, and exhaust emissions. The emissions from the engines have been determined using a gas emissions analyser. The outcomes of the experiment have been analysed based on engine torque, braking power, and exhaust emissions. Based on the analysis, torque, brake power, and emissions data obtained from the dynamometer engine, RON 100 has a higher and smoother performance than RON 95.

Experimental investigation of emissions from a single-cylinder diesel engine using methanol–diesel blends

This study examines the effects of methanol–diesel blends on the emissions of a diesel engine, concentrating on carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), hydrocarbons (HCs), and particulate matter (PM). Using a single-cylinder four-stroke diesel engine at varying torque settings (2 N m–6 N m), significant reductions in CO, CO2, HC, and PM emissions were observed with increasing methanol content. CO emissions reduced by up to 81.8%, CO2 by up to 64.2%, HC by up to 80.4%, and PM by up to 23.5% with the MD11 blend. NOx emissions initially increased but decreased by up to 20% at higher torques with the same blend. These results highlight the environmental benefits of methanol–diesel blends and the need for effective NOx reduction strategies.

Numerical Analysis of the Effect of Ethanol-Gasoline Blends on a Single-Cylinder Spark-Ignition Engine Performance and Emissions

— With the rapid increase in the number of vehicles fueled by gasoline plying on the roads, there has been a rising need in the search for alternative fuels, which are more environmental friendly in order to reduce the amount of vehicular exhaust emissions. This can be achieved by using blended mixtures of gasoline with alcoholic fuels among which, ethanol is found to be most suitable due to its easy availability, low costs, safety and low impact on the engine performance. This study aims to investigate the performance of a single-cylinder, four-stroke spark-ignition engine using different ethanol-gasoline blends, namely E0, E10, E20 and E30. The engine's torque, brake power, brake thermal efficiency, brake-specific fuel consumption, and exhaust emissions were analysed using numerical simulation. Results revealed that raising the proportion of ethanol in the fuel mixture resulted in reduced brake power and torque upto 16% as a result of decrease in calorific value of the mixture. The engine's brake thermal efficiency decreased by upto 3% while the brake-specific fuel consumption increased upto 12% with increase in ethanol concentration. Exhaust emissions, including NOx and HC, were found to be influenced by engine speed, with NOx emissions increasing and HC emissions decreasing as speed increased. The study also revealed that increasing ethanol concentration in the fuel resulted in reduced engine exhaust emissions by upto 47% and 10% for NOX and HC emissions respectively. The study concluded that among all the blends used, optimum performance was obtained for E30 blend with reduction in exhaust emissions but at the expense of slight reduction in engine performance.

Applied AMT machine learning and multi-objective optimization for enhanced performance and reduced environmental impact of sunflower oil biodiesel in compression ignition engine

Biodiesel has emerged as a compelling substitute for conventional diesel fuel, providing a sustainable and eco-friendly choice for fueling compression ignition engines. This comprehensive study investigates the influence of biodiesel, specifically derived from sunflower oil, through the esterification method, on crucial engine performance parameters and environmental effects. The study examines the impact of varying engine torque on the performance of a single-cylinder, four-stroke compression ignition engine, encompassing parameters such as brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC), as well as exhaust emissions, including unburned hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). Four distinct biodiesel blends (B10, B20, B30, B40) with varying sunflower oil content are systematically compared to pure diesel (B0). The engine operates at a consistent speed of 1700 rpm, while the torque undergoes controlled adjustments from 0 to 10 Nm. Subsequently, this study explores the application of an alternating model tree (AMT) machine learning algorithm to establish relationships between independent factors, specifically torque and biodiesel volume (%vol), and dependent variables, including BTE, BSFC, CO, and NOx in a combustion engine. Additionally, the study employs a multi-objective ameliorative whale optimization algorithm (AWOA) to optimize the model's output. The objective is to identify optimal values for torque and%vol that maximize engine performance (BTE) while minimizing engine emissions (CO and NOx) and reducing fuel consumption (BSFC). The optimization process yields noteworthy results, with AWOA achieving peak BTE at 29.714 %, BSFC at 0.262 kg.kWh-1, and NOx emissions at 992 ppm at torque 7.3 N.m and 13% vol. In contrast, particle swarm optimization (PSO) secured the minimum CO level at 0.123 %, with torque set at 7.6 N.m and 26% vol. The AMT models demonstrate high prediction accuracy, with coefficient of determination (R2) values exceeding 0.98.