Characterization of the distribution-nozzle operation for mixture homogenization by a late-diesel-injection strategy

2011 ◽  
Vol 226 (4) ◽  
pp. 529-546 ◽  
Author(s):  
M Weclas ◽  
J Cypris
Keyword(s):  
Combustion Process ◽  
Injection Pressure ◽  
Ignition Timing ◽  
Mixture Formation ◽  
Penetration Length ◽  
Injection Strategy ◽  
Fuel Distribution ◽  
Diesel Injection ◽  
Fuel Vaporization ◽  
Homogeneous Combustion

In order to realize a homogeneous combustion process it is necessary to decouple this combustion process from fuel injection. This homogeneous combustion process requires the charge to be homogeneous prior to simultaneous volumetric ignition. This kind of ignition is a self-ignition process requiring control of the ignition timing. A late-injection strategy as used in a conventional diesel engine permits control of the ignition timing; however, the time available for mixture formation and the homogenization process is very limited. The present paper deals with a distribution-nozzle concept which combines both strategies: a late-injection strategy for controlling the ignition timing with significantly accelerated fuel distribution in space and corresponding mixture homogenization. The distribution-nozzle concept combines a conventional diesel nozzle with a porous element (ring) positioned in proximity to the nozzle outlet. Because of multi-jet splitting as a result of the diesel-jet interaction with a porous structure, the fuel leaving the porous ring spreads widely in space. Additionally, a very effective fuel vaporization process occurs within the porous structure, supporting quick mixture formation. The paper describes both the fuel distribution in space and its vaporization for different configurations of the distribution elements, the injection pressure, and the porous ring temperature. In comparison with a free diesel injection, the distribution nozzle results in a significantly increased fuel surface area, a reduced jet penetration length, a reduced jet velocity, and very quick fuel vaporization. This process is three dimensional in nature. Depending on the distribution-element structure, the geometry, and its temperature, as well as the injection pressure, the contributions of multi-jet splitting, and fuel vaporization, are different with respect to the surface area, penetration length, and exit velocity, as well as intensity distribution. Generally, at higher injection pressures these parameters are less temperature dependent, except for the fact that the intensity distribution is a function of the fuel vapour’s concentration.

Review of the Investigation of Fuel-Air Premixing and Combustion Process Using Rapid Compression Machine and Direct Visualization System

2013 ◽  
Vol 465-466 ◽  
pp. 265-269 ◽  
Author(s):  
Mohamad Jaat ◽  
Amir Khalid ◽  
Bukhari Manshoor ◽  
Siti Mariam Basharie ◽  
Him Ramsy
Keyword(s):  
High Speed ◽  
Combustion Engine ◽  
Early Stage ◽  
Combustion Process ◽  
Injection Pressure ◽  
Rapid Compression Machine ◽  
Mixture Formation ◽  
Visualization System ◽  
Optical Visualization ◽  
Rapid Compression

s :This paper reviews of some applications of optical visualization system to compute the fuel-air mixing process during early stage of mixture formation and late injection in Diesel Combustion Engine. This review has shown that the mixture formation is controlled by the characteristics of the injection systems, the nature of the air swirl and turbulence in thecylinder, and spray characteristics. Few experimental works have been investigated and found that the effects of injection pressure and swirl ratio have a great effect on the mixture formation then affects to the flame development and combustion characteristics.This paper presents the significance of spray and combustion study with optical techniques access rapid compression machine that have been reported by previous researchers. Experimental results are presentedin order to provide in depth knowledge as assistance to readers interested in this research area. Analysis of flame motion and flame intensity in the combustion chamber was performed using high speed direct photographs and image analysis technique. The application of these methods to the investigation of diesel sprays highlights mechanisms which provide a better understanding of spray and combustion characteristics.

Analysis of Fuel Injection Parameter on Biodiesel and Diesel Spray Characteristics Using Common Rail System

2014 ◽  
Vol 974 ◽  
pp. 362-366 ◽  
Author(s):  
Amir Khalid ◽  
Azwan Sapit ◽  
M.N. Anuar ◽  
Him Ramsy ◽  
Bukhari Manshoor ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Common Rail ◽  
Spray Angle ◽  
Injection System ◽  
Injection Timing ◽  
Ignition Process ◽  
Mixture Formation ◽  
Spray Characteristics ◽  
Penetration Length

Precise control of fuel injection is essential in modern diesel engines especially in controlling the precise injection quantity, flexible injection timing, flexible rate of injection with multiple injections and high injection pressures. It was known that the fuel-air mixing is mainly influenced by the fuel injection system and injector nozzle characteristics. Thus, mixture formation during ignition process associated with the exhaust emissions. The purpose of this study is to investigate the influence of spray characteristics on the mixture formation. In this study, common rail injector systems with different model of injector were used to simulate the actual mixture formation inside the engine chamber. The optical visualization system was constructed with a digital video camera in order to investigate the detailed behavior of mixture formation. This method can capture spray penetration length, spray angle, spray evaporation and mixture formation process clearly. The spray characteristic such as the penetration length, spray angle and spray area are increasing when the injection pressure increased. The mixture formation can be improved effectively by increasing the injection pressure.

Pressure Injection Influence on the Combustion Process

2014 ◽  
Vol 659 ◽  
pp. 450-455 ◽  
Author(s):  
Adrian Sabau
Keyword(s):  
Chemical Reaction ◽  
Arrhenius Equation ◽  
Computational Simulation ◽  
Combustion Process ◽  
Injection Pressure ◽  
Combustible Mixture ◽  
Experimental Result ◽  
Mixture Formation ◽  
Pressure Injection ◽  
Di Diesel Engine

Computational simulation for the combustion process in a DI diesel engine was performed through a code made by the author [1]. Two conditions of different injection pressure were examined in the simulation. The injection pressures are 150 MPa and 500 MPa. The combustion phenomenon was modeled as a combined process of formation of a combustible mixture and a chemical reaction. The rate of mixture formation was assumed to be dependent on the turbulence characteristics and the concentration of species in each computational cell. The rate of chemical reaction is described as an Arrhenius equation. The result agrees with the experimental result qualitatively, and the effect of injection pressure on the combustion process is well predicted.

Effect of injection strategy on the mixture formation and combustion process in a gasoline direct injection rotary engine

Fuel ◽  
2021 ◽  
Vol 304 ◽  
pp. 121428
Author(s):  
Changwei Ji ◽  
Ke Chang ◽  
Shuofeng Wang ◽  
Jinxin Yang ◽  
Du Wang ◽  
...  
Keyword(s):  
Direct Injection ◽  
Combustion Process ◽  
Gasoline Direct Injection ◽  
Mixture Formation ◽  
Injection Strategy ◽  
Rotary Engine

scholarly journals Detailed Injection Strategy Analysis of a Heavy-Duty Diesel Engine Running on Rape Methyl Ester

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Nikita Zuev ◽  
Andrey Kozlov ◽  
Alexey Terenchenko ◽  
Kirill Karpukhin ◽  
Ulugbek Azimov
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Pressure Rise ◽  
Base Case ◽  
Biodiesel Fuel ◽  
Pilot Injection ◽  
Post Injection ◽  
Heavy Duty ◽  
Injection Strategy ◽  
Fuel Mass

Using biodiesel fuel in diesel engines for heavy-duty transport is important to meet the stringent emission regulations. Biodiesel is an oxygenated fuel and its physical and chemical properties are close to diesel fuel, yet there is still a need to analyze and tune the fuel injection parameters to optimize the combustion process and emissions. A four-injections strategy was used: two pilots, one main and one post injection. A highly advanced SOI decreases the NOx and the compression work but makes the combustion process less efficient. The pilot injection fuel mass influences the combustion only at injection close to the top dead center during the compression stroke. The post injection has no influence on the compression work, only on the emissions and the indicated work. An optimal injection strategy was found to be: pilot SOI 19.2 CAD BTDC, pilot injection fuel mass 25.4%; main SOI 3.7 CAD BTDC, main injection fuel mass 67.3% mg; post SOI 2 CAD ATDC, post injection fuel mass 7.3% (the injection fuel mass is given as a percentage of the total fuel mass injected). This allows the indicated work near the base case level to be maintained, the pressure rise rate to decrease by 20% and NOx emissions to decrease by 10%, but leads to a 5% increase in PM emissions.

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