Showing papers on "Four-stroke engine published in 2022"

Investigation of the effect of compression ratio on the energetic and exergetic performance of a CI engine operating with safflower oil methyl ester

Abstract: This study examines the energy and exergy analyses for a single-cylinder, four-stroke, direct-injection, compression-ignition (CI) engine when it was run on the safflower (Carthamus tinctorius L.) oil methyl ester (SOME) and traditional diesel (as reference fuel) at various engine loading conditions (from 25% to full load in 25% steps) at a fixed speed of 1500 rpm. In addition, the compression ratio (CR) was changed between 12:1 and 18:1 in order to monitor its effect on the engine characteristics. The experimental outcomes obtained from the above-stated analyses showed that the tested engine spent more alternating fuel because of its lower energy content than that of diesel fuel in an effort to ensure the output power to be the same for the test fuels. Furthermore, the results exhibited that the energetic and exergetic efficiency enhanced with the increase of load and CR. In this contest, at the CR of 18:1 and full load, the maximum energy efficiency values for SOME and diesel fuel were found to be 28.67% and 29.78%, respectively meanwhile the related exergetic efficiency values were calculated to be 26.41% and 27.94%, respectively. The minimum exergy destruction figures were revealed at the CR of 18:1 and a load of 100% for tested fuels with the findings of 56.59% for SOME and 55.22% for diesel fuel. In conclusion, the results of the conducted analyses for the tested diesel engine powered by SOME appeared to be fairly close to those of diesel fuel at various loads and CRs. SOME will eventually be classified as an alternate fuel to petroleum-based diesel fuel.

Theoretical and Experimental Analysis of Engine Performance and Emissions Fuelled with Jojoba Biodiesel

Abstract: Over many decades, isolated regions (e.g., islands, rural and remote areas) have heavily relied on diesel engine for producing power and energy. However, due to depleting fossil fuels and concerning emissions, biodiesels could be the substitute for diesel in power generation sectors. This study developed a single-zone thermodynamic model to predict the engine performances such as brake power (BP), torque, brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC) and ignition delay (ID) times for diesel and jojoba biodiesel. The experiments were conducted on a fully automated, 4-cylinder, 4-stroke, liquid-cooled direct injection 3.7-L diesel engine fueled with diesel (D100) and three jojoba blends (JB5, JB10, and JB20) to validate the model. The performance simulation results agreed with experimental data for all tested fuels at 1200 to 2400 rpm speed and 25%, 50%, 75%, and 100% loading operation. The minimum error (3.7%) was observed for BP for D100 at 2000 rpm and 100% load, and the maximum error (19.2%) was found for JB10 at 1200 rpm and 25% loading operation. As load increases from 25 to 100%, the BSFC and torque difference between diesel and JB20 decreases from 10 to 6.5 and 9 to 6%, respectively. A shorter ID time was observed in JB5 compared to JB10 and JB20. Furthermore, a significant reduction was observed in CO (7.55%) and HC (6.65%) emission for JB20 at 25% and 1200 rpm compared to diesel fuel; however, NOx emission was increased up to 10.25% under any given conditions.

Comparative Study of TiO2 Nanoparticles and Alcoholic Fuel Additives-Biodiesel-Diesel Blend for Combustion, Performance, and Emission Improvements

Abstract: In the current research, the engine performance, combustion, and emission parameters of biodiesel mixture 20% Tamarind oil methyl ester and 80% Diesel (B20) with the inclusion of titanium dioxide (TiO2) in different concentrations (25.50 and 75 ppm) and 10% v/v dimethyl carbonate (DMC) as fuel additive investigated using a single-cylinder, 4-stroke, direct injection (DI), compression ignition (CI) engine. The nano fuel blends were prepared through the ultrasonication process. The ratio of 1:4 TiO2: QPAN80 was produced higher stability and consistency out of five trials. TiO2 were characterized using FESEM, HR-TEM, Fourier Transform Infrared (FTIR), and X-Ray diffraction. Fuel properties were determined as per the ASTM standards. Engine tests were carried out to determine the engine performance under varied loads such as 25, 50, 75, and 100% while keeping a uniform speed of 1500 rpm. The maximum reduction in BSFC, CO, HC, and NOx were found to be 17.64%, 9.49%, 7.81%, and 6.53%, and the increased BTE was observed to be 6.13% for B20T50DMC10 compared to B20 blend at full load. Thus, the combined effect of TiO2 and DMC served excellent engine performance, combustion, and emission characteristics in CI engine operation.

Investigation of the Performance and Emission Characteristics of Diesel Engine Fueled with Biogas-Diesel Dual Fuel

Abstract: Due to the popularity of diesel engines, utilization of fossil fuel has increased. However, fossil fuel resources are depleting and their prices are increasing day by day. Additionally, the emissions from the burning of petroleum-derived fuel is harming the global environment. This work covers the performance and emission parameters of a biogas-diesel dual-fuel mode diesel engine and compared them to baseline diesel. The experiment was conducted on a single-cylinder and four-stroke DI diesel engine with a maximum power output of 2.2 kW by varying engine load at a constant speed of 1500 RPM. The diesel was injected as factory setup, whereas biogas mixes with air and then delivered to the combustion chamber through intake manifold at various flow rates of 2, 4, and 6 L/min. At 2 L/min flow rate of biogas, the results were found to have better performance and lower emission, than that of the other flow; with an average reduction in BTE, HC, and NOx by 11.19, 0.52, and 19.91%, respectively, and an average increment in BSFC, CO, and CO2 by 11.81, 1.05, and 12.8%, respectively, as compared to diesel. The diesel replacement ratio was varied from 19.56 to 7.61% at zero engine load and 80% engine load with biogas energy share of 39.6 and 16.59%, respectively.

A Numerical Study on Fuel Injection Optimization for a ME-GI Dual-Fuel Marine Engine Based on CFD Analysis

Abstract: A numerical study was carried out to investigate the effects of injector spray angle (SA) and injection position (IP) on the combustion and emission characteristics of a two-stroke ME-GI marine engine at full load. Three-dimensional (3D) simulations of the combustion process and emission formations inside the cylinder of the engine operating in the diesel and DF modes were performed using the ANSYS Fluent simulation software to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were compared and showed good agreement with the experimental results reported in the engine’s shop test technical data. The simulation results showed that the IP of 0.02 m with an SA of 40 degrees helps to enhance the engine performance; however, if the main target is reducing engine exhaust gas emissions, an IP of 0.01 m is highly recommended to be used. At this IP, the specific SA of 40, 45, or 50 degrees that should be used will depend on which emissions (NO, soot, CO2, etc.) need to be reduced. This study successfully investigated the effects of injector SA and IP on the combustion and emission characteristics of the researched engine and would be a good reference for engine design and operating engineers.

Assessment of Diesel Engine Performance, Combustion and Emission Characteristics with Supplementation of Neem Oil Methyl Ester Along With EGR

Abstract: Biodiesel generated from a variety of non-edible feedstocks has gained widespread acceptance as a limited diesel fuel alternative in compression ignition engines. For the reliable implementation of biodiesel in commercial sectors, its effect on engine combustion, emission, and performance needs to be examined experimentally. In this study, 10% (N10) and 20 % (N20) Neem oil methyl ester (NME) blends were tested in a direct injection 4-stroke single-cylinder diesel engine incorporated with 5% and 10% exhaust gas recirculation (EGR). At maximum load conditions, Brake thermal efficiency (BTE) was found highest for N20 by 7.2%, and also Brake specific energy consumption (BSEC) was reduced by 11.4% for N20 as compared to diesel. Meanwhile, the incorporation of EGR deteriorates the performance parameters for the N20 blend. The results of emission analysis showed that oxides of nitrogen (NOx) increased with the addition of biodiesel whereas the addition of EGR diminished the NOx value for both biodiesel blends at all loading conditions. Unburnt hydrocarbon (UHC), Carbon monoxide (CO), and smoke emissions decreased by 40.6%, 31.2%, and 29.6% for the N20 blend respectively at full load when compared to diesel. Interestingly, when EGR was provided, CO, UHC, and smoke density values are increased for both N10 and N20 blends at all loading conditions, however lower than diesel operation.

Analysis of the effects of lubricating oil viscosity and engine speed on piston-cylinder liner frictions in a single cylinder HCCI engine by GT-SUITE program

Abstract: Engines with homogenous charge compression ignition (HCCI) are the low-temperature combustion models in which automatic oxidation reactions occur with the effect of in-cylinder pressure and heat at the end of preparation of homogenous air-fuel mixture and compression stroke within the cylinder by means of port injection or early direct injection. In-cylinder gas temperatures of such engines during the cycle are lower than conventional internal combustion engines. Therefore, they cause zero NOx and soot emissions. Moreover, the occurrence of combustion in very small crankshaft angles results in a decrease in heat losses observed in cylinder walls and an increase in thermal efficiency. Reducing mechanical friction is highly significant for increasing the effective productivity of HCCI engines. In internal combustion engines, 10% of total energy obtained from the fuel is spent on the heat emerging due to mechanical frictions. 20% of mechanical friction results from the friction occurring between piston ring and liners. In this article, frictional characteristics of compression ring (TOP) and piston skirt area have been examined for two different engine speeds and lubricants, by using technical properties of single-cylinder HCCI engine and in-cylinder pressure and temperature data obtained under full load by means of GT-SUITE software. As the increase in pressure, occurring inside the cylinder at the end of the exhaust stroke and at the beginning of intake stroke, increases ring pressure load in HCCI engines, higher level of piston ring frictions has been observed when compared to internal combustion engines with the same technical properties. Piston ring contact pressure force is a more effective parameter in terms of piston frictions, when compared to hydrodynamic pressure force. The use of lubricants with higher viscosity (SAE 10W-40) has enabled the piston to move more laterally. According to the analysis results, a maximum piston speed of 3.92 m/s for 800 rpm engine speed and 7.85 m/s for 1600 rpm engine speed has been obtained. Maximum friction power losses have been found as 63.84 W at 800 rpm engine speed and 85.91 W at 1600 rpm engine speed. Oil film thickness has obtained in the middle of the piston stroke in the intake, compression, power and exhaust strokes, respectively, 1.809, 1.674, 1.547 and 1.792 µm at 800 rpm engine speed and 1.101, 1.018, 0.932 and 1.119 µm at 1600 rpm engine speed.

Exergy analysis of a single-cylinder four-stroke gasoline engine

Abstract: In developing countries, the four-stroke single-cylinder gasoline engine finds wide use. Motorcycles, tricycles and household machines like vegetable grinding machines are but a few of the machinery which run on this engine. Researchers have found that this engine is inefficient and consumes a lot of fuel, in light of sustainability and energy efficiency, this study aimed to perform an exergy analysis of a single-cylinder 4-stroke gasoline engine to determine how best its efficiency can be improved. Parameters such as brake thermal power, exergy efficiency, the quantity of exergy destruction and the component of the engine which is the most influential on its efficiency were determined while varying the engine’s torque. A G200K1 Honda engine was used as the study material. At the lowest tested torque of 9.4Nm, a corresponding brake power output of 2.4609kW and efficiency of 17.07% was measured, while at a higher torque 9.70Nm, a corresponding brake power output of 2.5395kW and efficiency of 17.62% was measured. It was also found that for every 1.06% rise in torque there is a corresponding 1.80% rise in brake power and exergy efficiency. It was concluded from the findings that the bulk of energy waste in the system comes from the high-temperature gas released from the engine’s exhaust. For the overall efficiency of four-stroke single-cylinder gasoline engines to be improved, the exergy destruction due to combustion should be minimised by optimizing the combustion temperature and reducing heat loss from the combustion chamber.

A single-zone thermodynamic model cycle simulation and optimization of combustion and performance characteristics of a diesel engine

Abstract: A one-cylinder compression ignition engine was investigated for the prediction of engine combustion and performance characteristics such as in-cylinder pressure (CP), rate of pressure rise (ROPR), heat release rate (HRR), ignition delay (ID), and engine performance characteristics such as indicated power (IP), brake power & torque (BP & BT), ISFC, BSFC, and BTE. The thermodynamic model was developed by coding the script in MATLAB software due to its simplicity and less computational time. The speed of the engine varying from 900 to 2400 rpm, compression ratio from 12 to 24, injection timing from 24° CA bTDC to 18° aTDC, and exhaust gas recirculation (EGR) from 10% to 90% were chosen as engine’s variables against which the combustion and performance parameters were evaluated. The optimization of the performance parameters was done using response surface methodology (RSM) based on BMEP, BTE, and BT. The best results were obtained while the engine was running at 1278 rpm, with a compression ratio of 12 and EGR of 80%, with an injection timing of −24° bTDC.