A comparative study of the effect of compression ratio on the efficiency and flame development angle in a Cooperative Fuel Research engine fueled with binary gasoline–alcohol blends

2019 ◽  
pp. 146808741985910 ◽  
Author(s):  
Guillermo Rubio-Gómez ◽  
Lis Corral-Gómez ◽  
David Rodriguez-Rosa ◽  
Fausto A Sánchez-Cruz ◽  
Simón Martínez-Martínez

In the last few years, increasing concern about the harmful effects of the use of fossil fuels in internal combustion engines has been observed. In addition, the limited availability of crude oil has driven the interest in alternative fuels, especially biofuels. In the context of spark ignition engines, bioalcohols are of great interest owing to their similarities and blend capacities with gasoline. Methanol and ethanol have been widely used, mainly due to their knocking resistance. Another alcohol of great interest is butanol, thanks to its potential of being produced as biofuel and its heat value closer to gasoline. In this study, a comparative study of gasoline–alcohol blend combustion, with up to 20% volume, with neat gasoline has been carried out. A single-cylinder, variable compression ratio, Cooperative Fuel Research-type spark ignition engine has been employed. The comparison is made in terms of fuel conversion efficiency and flame development angle. Relevant information related to the impact in the combustion process of the use of the three main alcohols used in blends with gasoline has been obtained.

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Sachin Kumar Gupta ◽  
Mayank Mittal

Abstract Biogas, which is a renewable alternative fuel, has high antiknocking properties with the potential to substitute fossil fuels in internal combustion engines. In this study, performance characteristics of a spark-ignition (SI) engine operated under methane (baseline case) and biogas are compared at the compression ratio (CR) of 8.5:1. Subsequently, the effect of CR on operational limits, performance, combustion, and emission characteristics of the engine fueled with biogas is evaluated. A variable compression ratio, spark-ignition engine was operated at various CRs of 8.5:1, 10:1, 11:1, 13:1, and 15:1 over a wide range of operating loads at 1500 rpm. Results showed that the operating range of the engine at 8.5:1 CR reduced when biogas was utilized in the engine instead of methane. However, the operating range of the engine for biogas extended with an increase in CR—an increase from 9.6 N-m-16.5 N-m to 2.8 N-m-15.1 N-m was observed when CR was increased from 8.5:1 to 15:1. The brake thermal efficiency improved from 13.7% to 16.3%, and the coefficient of variation (COV) of indicated mean effective pressure (IMEP) reduced from 12.7% to 1.52% when CR was increased from 8.5:1 to 15:1 at 8 N-m load. The emission level of carbon dioxide was decreased with an increase in CR due to an improvement in the thermal efficiency and the combustion process.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7037
Author(s):  
Donatas Kriaučiūnas ◽  
Tadas Žvirblis ◽  
Kristina Kilikevičienė ◽  
Artūras Kilikevičius ◽  
Jonas Matijošius ◽  
...  

Biogas has increasingly been used as an alternative to fossil fuels in the world due to a number of factors, including the availability of raw materials, extensive resources, relatively cheap production and sufficient energy efficiency in internal combustion engines. Tightening environmental and renewable energy requirements create excellent prospects for biogas (BG) as a fuel. A study was conducted on a 1.6-L spark ignition (SI) engine (HR16DE), testing simulated biogas with different methane and carbon dioxide contents (100CH4, 80CH4_20CO2, 60CH4_40CO2, and 50CH4_50CO2) as fuel. The rate of heat release (ROHR) was calculated for each fuel. Vibration acceleration time, sound pressure and spectrum characteristics were also analyzed. The results of the study revealed which vibration of the engine correlates with combustion intensity, which is directly related to the main measure of engine energy efficiency—break thermal efficiency (BTE). Increasing vibrations have a negative correlation with carbon monoxide (CO) and hydrocarbon (HC) emissions, but a positive correlation with nitrogen oxide (NOx) emissions. Sound pressure also relates to the combustion process, but, in contrast to vibration, had a negative correlation with BTE and NOx, and a positive correlation with emissions of incomplete combustion products (CO, HC).


2020 ◽  
Vol 180 ◽  
pp. 01010
Author(s):  
Cristian Sandu ◽  
Constantin Pană ◽  
Niculae Negurescu ◽  
Alexandru Cernat ◽  
Cristian Nuţu ◽  
...  

For conventional internal combustion engines alternative fuels such alcohols (ethanol, methanol and butanol) have attracted more attention. This aspect is due to the fact that alcohols have good combustion properties and high oxygen content. Butanol is a viable fuel for blending with conventional fuels such as gasoline or diesel because of its high miscibility with these conventional fuels. The high combustion speed of butanol compared to that of gasoline ensures a shorter burning process thus the engine thermal efficiency can potentially be improved. Moreover, the additional oxygen content of the alcohol n-butanol can potentially improve the combustion process and can lead to a reduction of carbon monoxide and unburnt hydrocarbons emissions level. Utilizing butanol-gasoline blends can provide a good solution for the reduction of greenhouse gases level (CO2) and pollutants level (CO, HC, and NOx). An experimental study was carried out in a spark ignition engine which was fueled with a blend of n-butanol-gasoline at different volume percentages. The objective of this paper is to determine the effects of butanol on the engine energetic performances and on the emissions (HC, CO and NOx). At first the engine fueled with pure gasoline to set up a reference at the engine load χ=55%, engine speed of n=2500 min-1 and different excess air coefficients (λ). After setting the reference the engine was fueled with butanol-gasoline blend (10% vol. butanol 90% vol. gasoline) with the same engine adjustments. At butanol use the CO, HC and CO2 emissions level decreased, but the NOx emission level increased. The butanol can be considered a good alternative fuel for the spark ignition engines without modifications.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.


2019 ◽  
Vol 26 (3) ◽  
pp. 31-38
Author(s):  
Wojciech Gis ◽  
Maciej Gis ◽  
Piotr Wiśniowski ◽  
Mateusz Bednarski

Abstract Limiting emissions of harmful substances is a key task for vehicle manufacturers. Excessive emissions have a negative impact not only on the environment, but also on human life. A significant problem is the emission of nitrogen oxides as well as solid particles, in particular those up to a diameter of 2.5 microns. Carbon dioxide emissions are also a problem. Therefore, work is underway on the use of alternative fuels to power the vehicle engines. The importance of alternative fuels applies to spark ignition engines. The authors of the article have done simulation tests of the Renault K4M 1.6 16v traction engine for emissions for fuels with a volumetric concentration of bioethanol from 10 to 85 percent. The analysis was carried out for mixtures as substitute fuels – without doing any structural changes in the engine's crankshafts. Emission of carbon monoxide, carbon dioxide, hydrocarbons, oxygen at full throttle for selected rotational speeds as well as selected engine performance parameters such as maximum power, torque, hourly and unit fuel consumption were determined. On the basis of the simulation tests performed, the reasonableness of using the tested alternative fuels was determined on the example of the drive unit without affecting its constructions, in terms of e.g. issue. Maximum power, torque, and fuel consumption have also been examined and compared. Thus, the impact of alternative fuels will be determined not only in terms of emissions, but also in terms of impact on the parameters of the power unit.


Author(s):  
Nicolas Iafrate ◽  
Anthony Robert ◽  
Jean-Baptiste Michel ◽  
Olivier Colin ◽  
Benedicte Cuenot ◽  
...  

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.


1999 ◽  
Author(s):  
Toshio Shudo ◽  
Yasuo Nakajima ◽  
Takayuki Futakuchi

Abstract Hydrogen has higher flame velocity and smaller quenching distance than hydrocarbon fuels, and is supposed to have special characteristics in combustion process of internal combustion engines. In this research, contributors to thermal efficiency in a hydrogen premixed spark ignition engine were analyzed and compared with methane combustion. Results showed hydrogen combustion had higher cooling loss to combustion chamber wall, and thermal efficiency of hydrogen combustion was mainly dominated by both cooling loss to combustion chamber wall and degree of constant volume combustion.


2021 ◽  
Vol 11 (13) ◽  
pp. 6035
Author(s):  
Luigi Teodosio ◽  
Luca Marchitto ◽  
Cinzia Tornatore ◽  
Fabio Bozza ◽  
Gerardo Valentino

Combustion stability, engine efficiency and emissions in a multi-cylinder spark-ignition internal combustion engines can be improved through the advanced control and optimization of individual cylinder operation. In this work, experimental and numerical analyses were carried out on a twin-cylinder turbocharged port fuel injection (PFI) spark-ignition engine to evaluate the influence of cylinder-by-cylinder variation on performance and pollutant emissions. In a first stage, experimental tests are performed on the engine at different speed/load points and exhaust gas recirculation (EGR) rates, covering operating conditions typical of Worldwide harmonized Light-duty vehicles Test Cycle (WLTC). Measurements highlighted relevant differences in combustion evolution between cylinders, mainly due to non-uniform effective in-cylinder air/fuel ratio. Experimental data are utilized to validate a one-dimensional (1D) engine model, enhanced with user-defined sub-models of turbulence, combustion, heat transfer and noxious emissions. The model shows a satisfactory accuracy in reproducing the combustion evolution in each cylinder and the temperature of exhaust gases at turbine inlet. The pollutant species (HC, CO and NOx) predicted by the model show a good agreement with the ones measured at engine exhaust. Furthermore, the impact of cylinder-by-cylinder variation on gaseous emissions is also satisfactorily reproduced. The novel contribution of present work mainly consists in the extended numerical/experimental analysis on the effects of cylinder-by-cylinder variation on performance and emissions of spark-ignition engines. The proposed numerical methodology represents a valuable tool to support the engine design and calibration, with the aim to improve both performance and emissions.


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