scholarly journals Knock Suppression of a Spark-Ignition Aviation Piston Engine Fuelled with Kerosene

Author(s):  
Enhua Wang ◽  
Chenyao Wang ◽  
Fujun Zhang ◽  
Huasheng Cui ◽  
Chuncun Yu ◽  
...  

Spark-ignition (SI) engine has a high power density, making it suitable for unmanned aerial vehicles. Normally, gasoline fuel with a high octane number (ON) is used for a spark-ignition engine. However, gasoline fuel is easy to be evaporated and has a low flash point which is unsafe for aviation engines. Kerosene with a high flash point is safer than gasoline. In this chapter, the combustion characteristics of kerosene for a spark-ignition aviation piston engine are analyzed. A three-dimensional (3D) model is setup, and the combustion process of the engine fuelled with kerosene is simulated. Later, the knock limit extension by water injection is evaluated experimentally. The results indicate that water injection can suppress the knock of SI engine with kerosene in some extent and the output power can be improved significantly.

2013 ◽  
Vol 17 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Jovan Doric ◽  
Ivan Klinar

A zero dimensional model has been used to investigate the combustion performance of a four cylinder petrol engine with unconventional piston motion. The main feature of this new spark ignition (SI) engine concept is the realization of quasi-constant volume (QCV) during combustion process. Presented mechanism is designed to obtain a specific motion law which provides better fuel consumption of internal combustion (IC) engines. These advantages over standard engine are achieved through synthesis of unconventional piston mechanism. The numerical calculation was performed for several cases of different piston mechanism parameters, compression ratio and engine speed. Calculated efficiency and power diagrams are plotted and compared with performance of ordinary SI engine. The results show that combustion during quasi-constant volume has significant impact on improvement of efficiency. The main aim of this paper is to find a proper kinematics parameter of unconventional piston mechanism for most efficient heat addition in SI engines.


Author(s):  
C D Rakopoulos ◽  
C N Michos ◽  
E G Giakoumis

Although a first-law analysis can show the improvement that hydrogen addition impacts on the performance of a biogas-fuelled spark-ignition (SI) engine, additional benefits can be revealed when the second law of thermodynamics is brought into perspective. It is theoretically expected that hydrogen enrichment in biogas can increase the second-law efficiency of engine operation by reducing the combustion-generated irreversibilities, because of the fundamental differences in the mechanism of entropy generation between hydrogen and traditional hydrocarbon combustion. In this study, an experimentally validated closed-cycle simulation code, incorporating a quasi-dimensional multi-zone combustion model that is based on the combination of turbulent entrainment theory and flame stretch concepts for the prediction of burning rates, is further extended to include second-law analysis for the purpose of quantifying the respective improvements. The analysis is applied for a single-cylinder homogeneous charge SI engine, fuelled with biogas—hydrogen blends, with up to 15 vol% hydrogen in the fuel mixture, when operated at 1500r/min, wide-open throttle, fuel-to-air equivalence ratio of 0.9, and ignition timing of 20° crank angle before top dead centre. Among the major findings derived from the second-law balance during the closed part of the engine cycle is the increase in the second-law efficiency from 40.85 per cent to 42.41 per cent with hydrogen addition, accompanied by a simultaneous decrease in the combustion irreversibilities from 18.25 per cent to 17.18 per cent of the total availability of the charge at inlet valve closing. It is also illustrated how both the increase in the combustion temperatures and the decrease in the combustion duration with increasing hydrogen content result in a reduction in the combustion irreversibilities. The degree of thermodynamic perfection of the combustion process from the second-law point of view is quantified by using two (differently defined) combustion exergetic efficiencies, whose maximum values during the combustion process increase with hydrogen enrichment from 49.70 per cent to 53.45 per cent and from 86.01 per cent to 87.33 per cent, respectively.


2011 ◽  
Vol 110-116 ◽  
pp. 3016-3024
Author(s):  
Moslem Yousefi ◽  
F. Ommi ◽  
Mehdi Farajpour

In this paper a three dimensional model of a spark ignition engine is presented using KIVA-3V code to investigate the combustion process of engine and gain a better understanding of what happens during this stage. The Whole engine cycle is simulated and the validity of the model is examined by experimental result of in-cylinder bulk pressure. the effect of ignition timing, spark plug location on the engine performance and pollutants of this engine has been investigated .The numerical results show that Relocating the spark plug near to the exhaust valves in order of taking advantage of higher temperature does not have the desired results. Using lean excessive air results in decreasing advancing the ignition results in an increase in the maximum bulk pressure and power of engine. Due to increase in maximum temperature of the combustion chamber the amount of NOx rises, too.


Energy ◽  
2019 ◽  
Vol 174 ◽  
pp. 1121-1132 ◽  
Author(s):  
Jair Leopoldo Loaiza Bernal ◽  
Janito Vaqueiro Ferreira

2021 ◽  
Vol 11 (4) ◽  
pp. 1441
Author(s):  
Farhad Salek ◽  
Meisam Babaie ◽  
Amin Shakeri ◽  
Seyed Vahid Hosseini ◽  
Timothy Bodisco ◽  
...  

This study aims to investigate the effect of the port injection of ammonia on performance, knock and NOx emission across a range of engine speeds in a gasoline/ethanol dual-fuel engine. An experimentally validated numerical model of a naturally aspirated spark-ignition (SI) engine was developed in AVL BOOST for the purpose of this investigation. The vibe two zone combustion model, which is widely used for the mathematical modeling of spark-ignition engines is employed for the numerical analysis of the combustion process. A significant reduction of ~50% in NOx emissions was observed across the engine speed range. However, the port injection of ammonia imposed some negative impacts on engine equivalent BSFC, CO and HC emissions, increasing these parameters by 3%, 30% and 21%, respectively, at the 10% ammonia injection ratio. Additionally, the minimum octane number of primary fuel required to prevent knock was reduced by up to 3.6% by adding ammonia between 5 and 10%. All in all, the injection of ammonia inside a bio-fueled engine could make it robust and produce less NOx, while having some undesirable effects on BSFC, CO and HC emissions.


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).


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.


2018 ◽  
Vol 244 ◽  
pp. 03001
Author(s):  
Donatas Kriaučiūnas ◽  
Saugirdas Pukalskas ◽  
Alfredas Rimkus

Numerical simulations of Nissan Qashqai HR16DE engine with increased compression ratio from 10,7:1 to 13,5:1 was carried out using AVL BOOST software. Modelled engine work cycles while engine works with biogas (BG) and hydrogen (H2) mixtures. For biogas used mixture of 35 % carbon dioxide (CO2) and 65 % methane (CH4). Three mixtures of biogas with added 5 %, 10 % and 15 % H2 was made. The simulation of engine work cycles was performed at fully opened throttle and changing engine crankshaft rotation speeds: ne1 = 1500, ne2 = 3000, ne3 = 4500, ne4 = 6000 rpm. Simulation results demonstrated what adding hydrogen to biogas increase in-cylinder temperature and nitrogen oxides (NOx) concentration because of higher mixtures lower heating values (LHV) and better combustion process. Other emissions of carbon monoxide (CO) and hydrocarbons (HC) decreased while adding hydrogen due to the fact that hydrogen is carbon-free fuel.


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