scholarly journals The technologies of improving the process of air-fuel mixture combustion in spark ignition engines

2020 ◽  
pp. 51-57
Author(s):  
A. P. Shaikin ◽  
◽  
I. R. Galiev ◽  
D. A. Pavlov ◽  
M. V. Sazonov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Internal Combustion Engine ◽  
Flame Propagation ◽  
Turbulence Intensity ◽  
Propagation Velocity ◽  
Combustion Engine ◽  
Combustion Process ◽  
Fuel Mixture ◽  
Flame Propagation Velocity ◽  
Combustion Phase

The paper considers the turbulence intensity and the fuel chemical composition impact on the flame propagation velocity at the initial and main combustion phases when changing the air-fuel mixture composition. The relevance of the study is caused by the fact that currently, the improvement of conventional engine operation characteristics is mainly achieved through the improvement of the fuel mixture combustion process. However, there are no data on the influence of chemical and gas-dynamic factors on the peculiarities of flame propagation at the initial and main combustion phases. The gas reciprocating internal combustion engine was the object of the research, and the subject of the study was the fuel combustion process. Fuel chemical composition changed due to the promoting addition of hydrogen to the natural gas and variations of the excess-air coefficient. The experiments carried out on the UIT-85 power plant (i.e. under the simulated internal combustion engine conditions) show that the promoting addition of hydrogen stronger influences the flame velocity in the initial combustion phase compared to the second combustion phase, as a combustion source in the first phase is a laminar flame bent front and depends only on chemical and thermo-physical properties of the fuel-air mixture. The analysis of experimental data showed the dual impact of turbulence intensity on the flame propagation velocity. In particular, at the beginning of the combustion process, the fluctuating velocity scarcely influences the flame propagation velocity, as opposed to the main combustion phase, where the flame propagation velocity increases at the increase of turbulence intensity.

scholarly journals Effects of Flame Propagation Velocity and Turbulence Intensity on End-Gas Auto-Ignition in a Spark Ignition Gasoline Engine

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5039
Author(s):  
Lei Zhou ◽  
Xiaojun Zhang ◽  
Lijia Zhong ◽  
Jie Yu
Keyword(s):  
Flame Propagation ◽  
Turbulence Intensity ◽  
Propagation Velocity ◽  
Gasoline Engine ◽  
Pressure Oscillation ◽  
Spark Ignition ◽  
Flame Propagation Velocity ◽  
Eddy Simulation ◽  
Auto Ignition ◽  
Large Eddy

Knocking is a destructive and abnormal combustion phenomenon that hinders modern spark ignition (SI) engine technologies. However, the in-depth mechanism of a single-factor influence on knocking has not been well studied. Thus, the major aim of the present study is to study the effects of flame propagation velocity and turbulence intensity on end-gas auto-ignition through a large eddy simulation (LES) and a decoupling methodology in a downsized gasoline engine. The mechanisms of end-gas auto-ignition as well as strong pressure oscillation are qualitatively analyzed. It is observed that both flame propagation velocity and turbulence have a non-monotonic effect on knocking intensity. The competitive relationship between flame propagation velocity and ignition delay of the end gas is the primary reason responding to this phenomenon. A higher flame speed leads to an increase in the heat release rate in the cylinder, and consequently, quicker increases in the temperature and pressure of the unburned end-gas mixture are obtained, leading to end-gas auto-ignition. Further, the coupling of a pressure wave and an auto-ignition flame front results in super-knocking with a maximum peak of pressure of 31 MPa. Although the turbulence indirectly influences the end-gas auto-ignition by affecting the flame propagation velocity, it can accelerate the dissipation of radicals and heat in the end gas, which significantly influences knocking intensity. Moreover, it is found that the effect of turbulence is more pronounced than that of flame propagation velocity in inhibiting knocking. It can be concluded that the intensity of the pressure oscillation depends on the unburned mixture mass as well as the local thermodynamic state induced by flame propagation and turbulence, with mutual interactions. The present work is expected to provide valuable perspective for inhibiting super-knocking of an SI gasoline engine.

scholarly journals Analysis of Air Flow, Air and Fuel Induction for Internal Combustion Engine

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Mohd Fitri Arshad ◽  
◽  
Muhammad Faris Ahmad ◽  
Amir Khalid ◽  
Izuan Amin Ishak ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Flow Behavior ◽  
Combustion Process ◽  
Engine Performance ◽  
Fuel Mixture ◽  
Internal Combustion ◽  
Spark Ignition Engine ◽  
Rotating Flow

In an internal combustion engine, performance, efficiency and emission formation depends on the formation of air-fuel mixture inside the engine cylinder. The fluid flow dynamics plays an important role for air-fuel mixture preparation to obtain the better engine combustion, performance and efficiency. This review article discuss the rotating flow (swirl and tumble) in premixed spark-ignition engine and its effect on turbulence generation and flame propagation. Rotating flow can substantially increase turbulence intensity for the duration of the combustion period. This review paper discusses the in-cylinder swirl and tumble flow that affects air induction during the combustion process in internal combustion engine. Alternatively, this study using computer simulation (Computational Fluid Dynamic, CFD) which offer the opportunity to carry out repetitive parameter studies. An integration-type flowmeter (IFM) also has been used which consists of ultrasonic flowmeter, that integrates the flowrate during the intake process, gives accurate measurements regardless of sampling time and frequency. Research parameter in this study was swirl and tumble that represents the fluid flow behavior occurred inside combustion chamber. Fuel injection and air mass also were the important parameters that have been discussed about in air induction process. The results obtain from the numerical analysis can be employed to examine the homogeneity of air-fuel mixture structure for better combustion process and engine performance.

Analysis and Research of the Combustion Process of YN4100QB Diesel Engine

2013 ◽  
Vol 744 ◽  
pp. 35-39
Author(s):  
Lei Ming Shi ◽  
Guang Hui Jia ◽  
Zhi Fei Zhang ◽  
Zhong Ming Xu
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engine ◽  
Combustion Chamber ◽  
Optimization Design ◽  
Combustion Engine ◽  
Geometric Model ◽  
Combustion Process ◽  
Internal Combustion ◽  
Engine Combustion ◽  
Exhaust Noise

In order to obtain the foundation to the research on the Diesel Engine YN4100QB combustion process, exhaust, the optimal design of combustion chamber and the useful information for the design of exhaust muffler, the geometric model and mesh model of a type internal combustion engine are constructed by using FIRE software to analyze the working process of internal combustion engine. Exhaust noise is the main component of automobile noise in the study of controlling vehicle noise. It is primary to design a type of muffler which is good for agricultural automobile engine matching and noise reduction effect. The present car mufflers are all development means. So it is bound to cause the long cycle of product development and waste of resources. Even sometimes not only can it not reach the purpose of reducing the noise but also it leads to reduce the engine dynamic. The strength of the exhaust noise is closely related to engine combustion temperature and pressure. The calculation and initial parameters are applied to the software based on the combustion model and theory. According to the specific operation process of internal combustion engine. Five kinds of common operation condition was compiled. It is obtained for the detailed distribution parameters of combusted gas temperature pressure . It is also got for flow velocity of the fields in cylinder and given for the relation of the parameters and crankshaft angle for the further research. At the same time NOx emissions situation are got. The numerical results show that not only does it provide the 3D distribution data in different crank shaft angle inside the cylinder in the simulation of combustion process, but also it provides a basis for the engine combustion ,emission research, the optimization design of the combustion chamber and the useful information for the designs of muffler.

Effect of Engine Operating Parameters on Combustion and Emission Characteristics

1992 ◽  
Author(s):  
Jiang Lu ◽  
Ashwani K. Gupta ◽  
Eugene L. Keating
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Internal Combustion ◽  
Operating Parameters ◽  
Emission Characteristics ◽  
Pollutants Emission

Abstract Numerical simulation of flow, combustion, heat release rate and pollutants emission characteristics have been obtained using a single cylinder internal combustion engine operating with propane as the fuel. The data are compared with experimental results and show excellent agreement for peak pressure and the rate of pressure rise as a function of crank angle. The results obtained for NO and CO are also found to be in good agreement and are similar to those reported in the literature for the chosen combustion chamber geometry. The results have shown that both the combustion chamber geometry and engine operating parameters affects the flame growth within the combustion chamber which subsequently affects the pollutants emission levels. The code employed the time marching procedure and solves the governing partial differential equations of multi-component chemically reacting fluid flow by finite difference method. The numerical results provide a cost effective means of developing advanced internal combustion engine chamber geometry design that provides high efficiency and low pollution levels. It is expected that increased computational tools will be used in the future for enhancing our understanding of the detailed combustion process in internal combustion engines and all other energy conversion systems. Such detailed information is critical for the development of advanced methods for energy conservation and environmental pollution control.

scholarly journals Assessment of thermodynamic cycle of internal combustion engine in terms of rightsizing

2019 ◽  
Vol 178 (3) ◽  
pp. 182-186
Author(s):  
Zbigniew SROKA ◽  
Maciej DWORACZYŃSKI
Keyword(s):  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Internal Combustion ◽  
Research Problem ◽  
Combustion Engines ◽  
Operating Characteristics ◽  
Swept Volume

The modification of the downsizing trend of internal combustion engines towards rightsizing is a new challenge for constructors. The change in the displacement volume of internal combustion engines accompanying the rightsizing idea may in fact mean a reduction or increase of the defining swept volume change factors and thus may affect the change in the operating characteristics as a result of changes in combustion process parameters - a research problem described in this publication. Incidents of changes in the displacement volume were considered along with the change of the compression space and at the change of the geometric degree of compression. The new form of the mathematical dependence describing the efficiency of the thermodynamic cycle makes it possible to evaluate the opera-tion indicators of the internal combustion engine along with the implementation of the rightsizing idea. The work demonstrated the in-variance of cycle efficiency with different forms of rightsizing.

Optical and Numerical Investigations of Flame Propagation in a Heavy Duty Spark Ignited Natural Gas Engine

2021 ◽  
Author(s):  
Jinlong Liu ◽  
Christopher Ulishney ◽  
Cosmin E. Dumitrescu
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Turbulence Intensity ◽  
Laminar Flame ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Heavy Duty ◽  
Piston Chamber

Abstract Increasing the natural gas (NG) use in heavy-duty engines is beneficial for reducing greenhouse-gas emissions from power generation and transportation. However, converting compression ignition (CI) engines to NG spark ignition operation can increase methane emissions without expensive aftertreatment, thereby defeating the purpose of utilizing a low carbon fuel. The widely accepted explanation for the low combustion efficiency in such retrofitted engines is the lower laminar flame speed of natural gas. In addition, diesel engine’s larger bowl size compared to the traditional gasoline engines increases the flame travel length inside the chamber and extends the combustion duration. However, optical measurements performed in this study suggested that a fast-propagating flame was developed inside the cylinder even at extremely lean operation. This was supported by a three-dimensional numerical simulation, which indicated that the squish region of the bowl-in-piston chamber generated a high turbulence intensity inside the bowl. However, the flame propagation experienced a sudden 2.25x reduction in speed when transiting from the bowl to the squish region. Such a phenomenon was caused by the large decrease in the turbulence intensity inside the squish region during the combustion process. Moreover, the squish volume trapped an important fuel fraction, and it is this fraction that experienced a slow and inefficient burning process during the expansion stroke. This resulted in increased methane emissions and reduced combustion efficiency. Overall, it was the specifics of the combustion process inside a bowl-in-piston chamber not the methane’s slow laminar flame speed that contributed to the low methane combustion efficiency for the retrofitted engine. The results suggest that optimizing the chamber shape is paramount to boost engine efficiency and decrease its emissions.

Sign in / Sign up

Export Citation Format

Share Document