Understanding the Acoustic Oscillations Observed in the Injection Rate of a Common-Rail Direct Injection Diesel Injector

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Julien Manin ◽  
Alan Kastengren ◽  
Raul Payri
Keyword(s):  
Acoustic Analysis ◽  
Direct Injection ◽  
Injection Rate ◽  
Common Rail ◽  
Acoustic Oscillations ◽  
Acoustic Features ◽  
Injection Process ◽  
Engine Combustion ◽  
Common Rail Injector ◽  
Engine Development

Measuring the rate of injection of a common-rail injector is one of the first steps for diesel engine development. The injected quantity as a function of time is of prime interest for engine research and modeling activities, as it drives spray development and mixing, which, in current diesel engines, control combustion. On the other hand, the widely used long-tube method provides results that are neither straightforward nor fully understood. This study, performed on a 0.09-mm axially drilled single-hole nozzle, is part of the Engine Combustion Network (ECN) and aims at analyzing the acoustic oscillations observed in the rate of injection signal and measuring their impact on the real injection process and on the results recorded by the experimental devices. Several tests have been carried out for this study, including rate of injection and momentum, X-ray phase-contrast of the injector, and needle motion or injector displacement. The acoustic analysis revealed that these fluctuations found their origin in the sac of the injector and that they were the results of an interaction between the fluid in the chamber (generally gases) or in the nozzle sac and the liquid fuel to be injected. It has been observed that the relatively high oscillations recorded by the long-tube method were mainly caused by a displacement of the injector itself while injecting. In addition, the results showed that these acoustic features are also present in the spray, which means that the oscillations make it out of the injector, and that this temporal variation must be reflected in the actual rate of injection.

Understanding the Acoustic Oscillations Observed in the Injection Rate of a Common-Rail DI Diesel Injector

2012 ◽  
Author(s):  
Julien Manin ◽  
Alan Kastengren ◽  
Raul Payri
Keyword(s):  
Acoustic Analysis ◽  
Injection Rate ◽  
Point Of View ◽  
Common Rail ◽  
Acoustic Oscillations ◽  
Real Rate ◽  
The Real ◽  
Injection Process ◽  
Engine Combustion ◽  
Common Rail Injector

Measuring the rate of injection of a common-rail injector is one of the first steps for diesel engine development. At the same time, this information is of prime interest for engine research and modeling as it drives spray development and mixing. On the other hand, the widely used long-tube method provides results that are neither straightforward, nor fully understood. This study performed on a 0.09 mm axially drilled single-hole nozzle is part of the Engine Combustion Network (ECN) and aims at analyzing these features from an acoustic point of view to separate their impact on the real injection process and on the results recorded by the experimental devices. Several tests have been carried out for this study including rate of injection and momentum, X-ray phase-contrast of the injector and needle motion or injector displacement. The acoustic analysis revealed that these fluctuations found their origin in the sac of the injector and that they were the results of an interaction between the fluid in the chamber (generally gases) and the liquid fuel to be injected. It has been observed that the relatively high oscillations recorded by the long-tube method were mainly caused by a displacement of the injector itself while injecting. In addition, the results showed that these acoustic features also appear on the momentum flux of the spray which means that the real rate of injection should present such behavior.

scholarly journals Providing Boot-Type Injection Rate Shape by Electric Impulse Control of the Common Rail Injector

2020 ◽  
pp. 32-42
Author(s):  
A.Y. Dunin ◽  
M.G. Shatrov ◽  
L.N. Golubkov ◽  
A.L. Yakovenko
Keyword(s):  
Diesel Engines ◽  
Fuel Injection ◽  
Control Valve ◽  
Road Construction ◽  
Injection Rate ◽  
Common Rail ◽  
Oxide Content ◽  
Common Rail Injector ◽  
Electric Impulse ◽  
The Common

For effective reduction of noise level and nitrogen oxide content in exhaust fumes of diesel engines, multistage fuel injection is used in combination with control of the front edge shape of the main injection. At the Moscow Automobile and Road Construction State Technical University (MADI), a method of control of the injection rate shape using an electric impulse was proposed, which was applied to the electromagnet of the control valve of the injector of the common rail fuel system. A computational and experimental analysis of the possibility of boot-type injection rate shape was carried out. The studies involved three most used designs of the common rail injector (CRI): CRI 1 featuring a control valve with shut-off cone and piston; CRI 2 consisting of a flat-lock control valve and a needle, which does not overlap the drain when the needle is in the highest position; CRI 3 with an injector that partially overlaps the drain. It was established that friction in the control valve piston and the guide surface pair of CRI 1 complicated the implementation of the boot-type injection rate due to its smoothing. CRI 2 and CRI 3 provide boot-type injection rate at different pressures in the fuel accumulator. The CRI 3 example shows that the instability of fuel supply during boot-type injection rate is comparable with that of fuel pre-injection, which is widely used in the organization of the common rail diesel engines working process.

scholarly journals Numerical Analysis of GDI Flash Boiling Sprays Using Different Fuels

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5925
Author(s):  
Raul Payri ◽  
Pedro Marti-Aldaravi ◽  
Rami Abboud ◽  
Abian Bautista
Keyword(s):  
Alternative Fuels ◽  
Fuel Injection ◽  
Ambient Pressure ◽  
Direct Injection ◽  
Saturation Pressure ◽  
Combustion Process ◽  
Gasoline Direct Injection ◽  
Injection Process ◽  
Engine Combustion ◽  
Flash Boiling

Modeling the fuel injection process in modern gasoline direct injection engines plays a principal role in characterizing the in–cylinder mixture formation and subsequent combustion process. Flash boiling, which usually occurs when the fuel is injected into an ambient pressure below the saturation pressure of the liquid, is characterized by fast breakup and evaporation rates but could lead to undesired behaviors such as spray collapse, which significantly effects the mixture preparation. Four mono–component fuels have been used in this study with the aim of achieving various flashing behaviors utilizing the Spray G injector from the Engine Combustion Network (ECN). The numerical framework was based on a Lagrangian approach and was first validated for the baseline G1 condition. The model was compared with experimental vapor and liquid penetrations, axial gas velocity, droplet sizes and spray morphology and was then extended to the flash boiling condition for iso–octane, n–heptane, n–hexane, and n–pentane. A good agreement was achieved for most of the fuels in terms of spray development and shape, although the computed spray morphology of pentane was not able to capture the spray collapse. Overall, the adopted methodology is promising and can be used for engine combustion modeling with conventional and alternative fuels.

scholarly journals INFLUENCE OF PRESSURE OSCILLATIONS IN COMMON RAIL INJECTOR ON FUEL INJECTION RATE

2020 ◽  
pp. 579
Author(s):  
Mikhail G. Shatrov ◽  
Andrey U. Dunin ◽  
Pavel V. Dushkin ◽  
Andrey L. Yakovenko ◽  
Leonid N. Golubkov ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Injection Rate ◽  
Common Rail ◽  
Needle Valve ◽  
Rail Pressure ◽  
Pressure Oscillations ◽  
Multiple Injections ◽  
Double Injection ◽  
Common Rail Injector

Fuel injection causes considerable oscillations of fuel pressure at the injector inlet. One of the reasons is hydraulic impact when the needle valve closes. For multiple injections, the previous injections affect the following. As both the fuel pressure in rail pac and the injection rate grow, the oscillations increase. The pressure oscillation range at the common rail injector inlet at pac=1500 bar is up to 350 bar, and at the rail pressure pac=500 bar, the amplitude decreases to 80 bar. Physical properties of the fuel are also important. As the viscosity of the fuel increases, its hydraulic friction grows which results in a rapid damping of pressure oscillations. The data for an injector operating on sunflower oil is presented. As compared with diesel fuel, the oscillations range decreases from 400 to 250 bar at the same operating mode. The influence of the interval between the impulses of a double injection on the injection rate of the second fuel portion was investigated. Superposition of two waves during multiple injections may result in amplification and damping of the oscillations. Simulation was performed to estimate the influence of fuel type and time interval Δτ between control impulses of a double injection on the injection quantity of the second portion at pressures of 2000-3000 bar. When the rail pressure pac grows, the oscillations and their impact on the injection process increase. For diesel fuel at pressure of pac=2000 bar, the variation in injection rates of the second portion is 2.36-4.62 mg, and at pac=3000 bar – 1.58-6.63 mg.

Combustion and Emission Characteristics of Biodiesel Fuels in a Common-Rail Diesel Engine

2005 ◽  
Author(s):  
Seung Hyun Yoon ◽  
Sung Wook Park ◽  
Dae Sik Kim ◽  
Sang Il Kwon ◽  
Chang Sik Lee
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Cetane Number ◽  
Injection Pressure ◽  
Injection Rate ◽  
Common Rail ◽  
Injection System ◽  
Emission Characteristics ◽  
Mixing Ratio ◽  
Biodiesel Fuels

A single cylinder DI (direct injection) diesel engine equipped with common-rail injection system was used to investigate the combustion and emission characteristics of biodiesel fuels. Tested fuels were conventional diesel and biodiesels obtained from unpolished rice oil and soybean oil. The volumetric blending ratios of biodiesel with diesel fuel are set at 0, 10, 20 and 40%. Experimental results show that the peak injection rate is reduced as the mixing ratio increased. The effect of the mixing ratio on the injection delay of biodiesel is not significant at the equal injection pressure. The peak combustion pressure was increased with the increase of the mixing ratio at an injection pressure of 100MPa. The ignition delay became shorter with the increase of the mixing ratio due to a higher cetane number of the biodiesel. HC and CO emissions are decreased at a high injection pressure. However, NOx emissions are increased at higher mixing ratios.

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