Investigation of the Influence of Injection Rate Shaping on the Spray Characteristics in a Diesel Common Rail System Equipped with a Piston Amplifier

2005 ◽  
Vol 127 (6) ◽  
pp. 1102-1110 ◽  
Author(s):  
J. Benajes ◽  
R. Payri ◽  
S. Molina ◽  
V. Soare

The quality of the mixing process of fuel and air in a direct injection diesel engine relies heavily on the way the spray develops when injected into the combustion chamber. Among other factors, the spray development depends on the injection rate of the fuel delivered by the injector. The paper presents a study, at both a macroscopic and microscopic level, of a Diesel spray generated by a common-rail injection system featuring a piston pressure amplifier. By modifying the timing and the duration of the injector and amplifier piston actuation, it is possible to obtain high injection pressures up to 180MPa, and different shapes for the injection rate, which would not be achievable with a regular common rail injection system. The spray evolution produced by three different injection rate shapes (square, ramp, and boot) has been investigated in an injection test rig, by means of visualization and PDPA techniques, at different injection conditions. The main conclusions are the important effect on spray penetration of the initial injection rate evolution and the small influence of the maximum injection pressure attained at the end of the injection event. Smaller or even negligible effects have been found on the spray cone angle and on the droplet Sauter mean diameter.

Author(s):  
Wei Fu ◽  
Lanbo Song ◽  
Tao Liu ◽  
Qizhao Lin

The objective of this paper is to investigate the spray macroscopic characteristics of biodiesel, diethyl carbonate (DEC)-biodiesel blends and diesel fuel based on a common-rail injection system. The spray tip penetration, spray cone angle and the spray projected area were measured through a high-speed photography method. The experimental results reveal that injection pressure and ambient pressure have significant effects on the spray characteristics. Higher injection pressure makes the spray tip penetration increase, while higher back pressure inside the chamber leads to the enlargement of the spray cone angle. The addition of DEC causes the blends fuels to have a shorter penetration and larger spray projected area, which reveals the potential capacity to improve the atomization process compared with biodiesel. The estimation of spray droplet size indicates that DEC30 generates a smaller Sauter mean diameter (SMD) because of its lower surface tension and viscosity. Model predictions were illustrated and compared with current work.


Author(s):  
O. Chiavola ◽  
F. Palmieri ◽  
G. Chiatti

A model for the analysis of diesel engine common rail injection system has been developed and the influence that different fuels have on the injection performances has been investigated. Diesel fuel, biodiesel and kerosene have been used and the differences of injection flow rate, injection pressure time trace, nozzle flow features and break up mechanism have been highlighted. The coupling of two different codes has been used in the simulations: the former one, AMESim code, has been adopted to model the common rail system and to investigate the fuel flow rate and the injection pressure dependence on the fuel type. The latter computational tool, FIRE code, has been initialized by means of the results obtained from the injection system simulation and has been used to perform the 3D investigation of the internal nozzle flow and of the spray formation phenomena, aimed at evaluating the effect of physical fuel features on local flow characteristics and their influence on the system performances. Details of the adopted modeling strategy are described and results of each simulation step are presented.


Author(s):  
Bong Woo Ryu ◽  
Seung Hwan Bang ◽  
Hyun Kyu Suh ◽  
Chang Sik Lee

The purpose of this study is to investigate the effect of injection parameters on the injection and spray characteristics of dimethyl ether and diesel fuel. In order to analyze the injection and spray characteristics of dimethyl ether and diesel fuel with employing high-pressure common-rail injection system, the injection characteristics such as injection delay, injection duration, and injection rate, spray cone angle and spray tip penetration was investigated by using the injection rate measuring system and the spray visualization system. In this work, the experiments of injection rate and spray visualization are performed at various injection parameters. It was found that injection quantity was decreased with the increase of injection pressure at the same energizing duration and injection pressure In the case of injection characteristics, dimethyl ether showed shorter of injection delay, longer injection duration and lower injected mass flow rate than diesel fuel in accordance with various energizing durations and injection pressures. Also, spray development of dimethyl ether had larger spray cone angle than that of diesel fuel at various injection pressures. Spray tip penetration was almost same development and tendency regardless of injection angles.


2018 ◽  
Vol 7 (4) ◽  
pp. 2594
Author(s):  
Razieh Pourdarbani ◽  
Ramin Aminfar

In this research, we tried to investigate all the fuel injection systems of diesel engines in order to select the most suitable fuel injection system for the OM357 diesel engine to achieve the highest efficiency, maximize output torque and reduce emissions and even reduce fuel consumption. The prevailing strategy for this study was to investigate the effect of injection pressure changes, injection timing and multi-stage injection. By comparing the engines equipped with common rail injection system, the proposed injector for engine OM357 is solenoid, due to the cost of this type of injector, MAP and controller (ECU). It is clear that this will not be possible only with the optimization of the injection system, and so other systems that influence engine performance such as the engine's respiratory system and combustion chamber shape, etc. should also be optimized. 


2001 ◽  
Author(s):  
M. Borghi ◽  
M. Milani ◽  
M. Piraccini

Abstract The paper is aimed at studying the overall dynamic behavior of the Common Rail Injection System actually used on a 4 cylinder industrial Diesel engine. Firstly, the paper introduces the main characteristics of a lumped and distributed parameters model of the high pressure branch of an actual Common Rail System, and the main hypotheses assumed to model it using a multi-port approach code for the analysis of the dynamic response of hydraulic systems submitted to fast transients. The model of the Common Rail System is then used to study its dynamic behavior when involved in the handling of the engine injection cycle for medium values of the crankshaft regime and for different pressure levels in the Rail. The analysis is performed applying to the injectors, to the pressure control valve and to the high-pressure pump the control strategies imposed by the Electronic Central Unit (ECU), as actually implemented into an industrial ECU for Diesel engine management. The model reliability and accuracy are evidenced through a numerical vs. experimental data comparison, mainly in term of rail pressure dynamic behavior. The analysis successively outlined in the paper allows to state how the hydraulic behavior of the Common Rail System interact with the electro-hydraulic injectors dynamics, and to determine the influence of this interaction on the total injected mass per cycle.


2014 ◽  
Vol 3 (2) ◽  
pp. 230
Author(s):  
N. Senguttuvan ◽  
S Raja ◽  
R. Sasidharan

Common rail direct fuel injection is a modern variant of direct fuel injection system for petrol and diesel engines. The common rail system prototype was developed in the late 1960s by Robert Huber of Switzerland and the technology further developed by Dr. Marco. In petrol engine MPFI technology was developed and implemented in earlier days. Basically common rail tube was fabricated by steel for petrol engines. In the current study Steel, Brass, Aluminum alloy a356 and ABS materials were analyzed separately and aluminum is found the best material among the steel, brass and ABS material for common rail injection tube. Keywords: Common Rail Injection System, Alternate Material.


2020 ◽  
pp. 146808742093649
Author(s):  
Zhixia He ◽  
Han Zhou ◽  
Lian Duan ◽  
Min Xu ◽  
Zhou Chen ◽  
...  

The cavitating flow in diesel injector nozzles plays a vital role in spray atomization and formation of fuel–air mixture, since vortex-induced string cavitation has recently been found a much more influence on spray compared to the ordinary geometry-induced film cavitation. In this study, in order to investigating string cavitation and its’ enhancement on spray, the visualization experimental platform for the real-size optical tapered-hole nozzle was built based on the high-pressure common rail fuel injection system. Groups of optical nozzles with different geometries were designed for exploring the couple effects of several nozzle geometric parameters, including nozzle sac chamber depth, nozzle-hole position height and needle lift, on the three-dimension vortex flow structure and then on the string cavitation and spray characteristics. Results indicated that the string cavitation characteristics are tightly associated with couple characteristics of the parameters. The stable and strong string cavitation during the whole injection process can be obtained in the Min-sac nozzle with the high hole position under the low needle lift. The string cavitation extends to the nozzle-hole outlet, and subsequently induces the special hollow cone spray with air in the spray center location and corresponding a larger spray cone angle even under not so high injection pressure.


Author(s):  
Junxing Hou ◽  
Huayang Zhang ◽  
Xiaodong An ◽  
Guoqiang Tian ◽  
Xuewei Yan

The dynamic injection behaviors of pure biodiesel, high-proportioned biodiesel blends, and low-proportioned biodiesel blends in a common-rail injection system are researched. The effects of biodiesel ratio in the blended fuel and injection condition on the injection rate, cycle injection quantity, and fuel line pressure at the injector inlet are determined. The findings show that the injection duration is extended with the decrease in biodiesel ratio in the blended fuel, and fluctuation amplitude of injection rate in the stable injection stage increases. The first four pressure peaks for pure biodiesel decrease rapidly, while for blends, they decrease slowly, which results in an increasing difference of four pressure peaks between pure biodiesel and blends. With the decrease in biodiesel ratio, the mean volume injection quantity for three fuels gradually increases in the same injection condition. The coefficient of variation of the cycle injection quantity value for biodiesel and its blends with 30 cycles increases. The coefficient of variation value for biodiesel is between 0.4% and 0.7%. Compared with pure biodiesel, the mean volume injection quantity for BD70 increases by about 20–32%, and the coefficient of variation value is between 0.7% and 1.7% for high-proportioned biodiesel blends. The mean volume injection quantity increases by about 36–43% for low-proportioned biodiesel blends and the coefficient of variation value is between 1.1% and 2.1%.


2000 ◽  
Vol 123 (2) ◽  
pp. 419-427 ◽  
Author(s):  
G. M. Bianchi ◽  
P. Pelloni ◽  
F. E. Corcione ◽  
L. Allocca ◽  
F. Luppino

This paper deals with a numerical and experimental characterization of a high-pressure diesel spray injected by a common-rail injection system. The experiments considered a free non-evaporating spray and they were performed in a vessel reproducing the practical density that characterizes a D.I. diesel engine at injection time. The fuel was supplied at high pressure by a common-rail injection system with a single hole tip. The computations have been carried out by using both the TAB model and a hybrid model that allows one to describe both liquid jet atomization and droplet breakup. In order to validate the breakup model, an extensive comparison between data and numerical predictions has been carried out in terms of spray penetration, Sauter mean diameter, near and far spray cone angles, and spray structure.


Sign in / Sign up

Export Citation Format

Share Document