scholarly journals Experimental Study on Influence of Fuel Injection Pressure on Dynamic Flow Characteristics of Solenoid Valve Injector

Author(s):  
Janwen Li ◽  
Wei Lei ◽  
Yanhao Li ◽  
Bin Liu
Author(s):  
Dan Xu ◽  
Qing Yang ◽  
Xiaodong An ◽  
Baigang Sun ◽  
Dongwei Wu ◽  
...  

The double-solenoid-valve fuel injection system consists of an electronic unit pump and an electronic injector. It can realize the separate control of fuel supply and injection and has the advantages of adjusting pressure by cycle and flexible controlling of the injection rate. The interval angle between the pilot and main injection directly affects the action degree and the characteristics of two adjacent injections, affecting engine performance. This work realizes multiple injection processes on the test platform of a high-pressure double-solenoid-valve fuel injection system, with maximum injection pressure reaching 200 MPa. In this study, the interval between driven current signal of pilot injection termination and that of main injection initiation is defined as the signal interval (DT1), whereas the interval between pilot injection termination and main injection initiation is defined as the injection interval (DT2). The differences between the signal and the injection intervals are calculated, and the variation rule of the difference with respect to the signal interval is analyzed. Results show that the variation rule of the difference with the signal interval first decreases, then increases, and finally decreases. The variation rule of the delay angle from the start of needle movement to the start of fuel injection is found to be the root cause of this rule. The influence of the injection pressure on needle deformation and fuel flow rate of the nozzle results in the variation rule. In addition, the influence of the cam speed, temperature, and pipe length on the difference between the signal and injection interval is determined. This research provides guidance for an optimal control strategy of the fuel injection process.


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3837 ◽  
Author(s):  
Sam Ki Yoon ◽  
Jun Cong Ge ◽  
Nag Jung Choi

This experiment investigates the combustion and emissions characteristics of a common rail direct injection (CRDI) diesel engine using various blends of pure diesel fuel and palm biodiesel. Fuel injection pressures of 45 and 65 MPa were investigated under engine loads of 50 and 100 Nm. The fuels studied herein were pure diesel fuel 100 vol.% with 0 vol.% of palm biodiesel (PBD0), pure diesel fuel 80 vol.% blended with 20 vol.% of palm biodiesel (PBD20), and pure diesel fuel 50 vol.% blended with 50 vol.% of palm biodiesel (PBD50). As the fuel injection pressure increased from 45 to 65 MPa under all engine loads, the combustion pressure and heat release rate also increased. The indicated mean effective pressure (IMEP) increased with an increase of the fuel injection pressure. In addition, for 50 Nm of the engine load, an increase to the fuel injection pressure resulted in a reduction of the brake specific fuel consumption (BSFC) by an average of 2.43%. In comparison, for an engine load of 100 Nm, an increase in the fuel injection pressure decreased BSFC by an average of 0.8%. Hydrocarbon (HC) and particulate matter (PM) decreased as fuel pressure increased, independent of the engine load. Increasing fuel injection pressure for 50 Nm engine load using PBD0, PBD20 and PBD50 decreased carbon monoxide (CO) emissions. When the fuel injection pressure was increased from 45 MPa to 65 MPa, oxides of nitrogen (NOx) emissions were increased for both engine loads. For a given fuel injection pressure, NOx emissions increased slightly as the biodiesel content in the fuel blend increased.


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