Study of Fuel Injection Quantity Fluctuation in High Pressure Common Rail System in Entire Operating Conditions

2012 ◽  
Vol 562-564 ◽  
pp. 1048-1053 ◽  
Author(s):  
Bing Qi Tian ◽  
Li Yun Fan ◽  
Xiu Zhen Ma ◽  
Hao Wang ◽  
Hong Bin Liu

Variations in high pressure common rail (HPCR) system characteristic parameters influence injection characteristics and lead to fluctuation of fuel injection quantity (FIQ). The fuel injection quantity fluctuation (FIQF) has adverse affects both on coherence and stability of HPCR system. Numerical simulation model of HPCR has been developed and its accuracy has been validated by experimental results. Influence law and generation mechanism of FIQF caused by variations of different parameters such as fuel return pressure, solenoid reset force, control valve lift, fuel return orifice (A orifice) diameter, fuel inlet orifice (Z orifice) diameter, injector needle lift, needle pre-tightening force and injector flow coefficient in entire operating conditions have been analyzed.

Author(s):  
Kun Yang ◽  
Lei Zhou ◽  
Gang Wang ◽  
Tao Nie ◽  
Xin Wu

In order to overcome the difficulties of high pressure source design and parts integration in the injector, realizing the ultra high pressure injection and controllable fuel injection rate, an ultra high pressure common rail system based on domestic basic materials and manufacturing technology level was proposed and designed. The working principle of this system was first introduced; the performance test bench of ultra high pressure common rail system was built. Then, the influence of pressure-amplifier device structure parameters on the pressurization pressure peak was analyzed quantitatively, and on the basis of selecting the most appropriate combination of parameters, the pressure and fuel injection rate control characteristics were conducted. The results show that ultra high pressure common rail system can magnify fuel pressure to ultra high pressure state (more than 200 MPa) and by changing the control signal timing of pressure-amplifier device and injector solenoid valve, the flexible and controllable fuel injection rate can be achieved. Under the condition of the same pressurization ratio, the peak value of pressurization pressure increases gradually, and with the increase of pressurization ratio, the increasing trend of the pressurization pressure peak value is nonlinear. At the same time, under the same condition of spring preload, the greater of the spring stiffness, the higher of the rail base pressure can bear, that means the pressure-amplifier device can achieve pressurization at a higher base pressure. But if the spring stiffness is too large, the solenoid valve of pressure-amplifier device will not be opened due to insufficient electromagnetic force, so the specific selection should be considered in a compromise.


2020 ◽  
pp. 146808742092161
Author(s):  
Ying Hu ◽  
Jianguo Yang ◽  
Nao Hu

The structure and performance of the common-rail system for the marine diesel engine are different from those used for automobile applications, resulting from the larger accumulator volume and the single injection volume. According to the characteristics of the distributed structure of the accumulator volume, a novel optimisation idea to improve the steady-state performance of the high-pressure common-rail fuel injection system designed for a marine engine retrofitting is proposed. The study concentrates on the optimisation in the hydraulic layouts and the structure parameters to manage the energy stored in the pressure waves. First, the test rig was established to study and evaluate the steady-state performance of the high-pressure common-rail system. Second, the experiments of rail orders and injection sequences were carried out to study the influence of different hydraulic layouts on the energy distribution of pressure waves in the system. Meanwhile, a comprehensive and detailed model of the high-pressure common-rail system was built to investigate the structural parameters of a rail-to-injector pipe. Based on the high-pressure common-rail system model, the modified multi-objective genetic algorithm was employed to seek the trade-off between the consistency of the injection volume and the reduction of the rail pressure fluctuation. Results show that a uniform distribution of multiple rails in one cycle contributed to reducing the amplitude of the rail pressure oscillation. In the parameter ranges of this study, a longer length and larger diameter of the rail-to-injector pipe could reduce the standard deviation of the injection volume and the rail pressure fluctuation rate simultaneously.


2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110261
Author(s):  
Ziguang Gao ◽  
Guoxiu Li ◽  
Chunlong Xu ◽  
Hongmeng Li ◽  
Min Wang

The high-pressure common rail system has been widely used owing to its precise control of fuel injection rate profile, which plays a decisive role in cylinder combustion, atomization, and emission. The fuel injection rate profile of high-pressure common rail system was studied, and a fuel injection rate profile calculation model is proposed. The model treats the injector as a black box. Some measured data are needed to calculate the parameters in the model. The rise and fall of injection rate is regarded as trigonometric function to reduce the complexity and increase the accuracy. The model was verified using two different types of fuel injectors. The model calculation results were evaluated under various data input conditions. The results show that the model has good applicability to different input data and injectors. In addition, because the model building requires a large amount of experimental data, a comprehensive analysis of various input data was also conducted. The injection profile was analyzed from a new perspective and the regularity of injection rate profile was established.


Measurement ◽  
2021 ◽  
Vol 170 ◽  
pp. 108716
Author(s):  
Quan Dong ◽  
Xiyu Yang ◽  
Hao Ni ◽  
Jingdong Song ◽  
Changhao Lu ◽  
...  

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