Experimental Investigation of the Needle Opening Pressure in High Pressure Double-Actuator Injection System

In order to realize the accurate and efficient control on the needle opening pressure (NOP) of the electronic injector in a high pressure double-actuator injection system, choosing control parameters as the test factors, the orthogonal design and range analysis were adopted to carry out the bench test of NOP change. Experimental results show that the cam phase difference between fuel injection timing and fuel supply timing has the greatest effect on NOP, followed by the order of fuel injection timing and crankshaft speed. The NOP increases almost linearly (whose slope is k) with the cam phase difference. When the injection timing is in range of 61° to 91°, k will increase with the fuel injection timing, and when the fuel injection timing is in the range of 91° to 101°, k remains unchanged. When the fuel injection timing increases to a critical value, the NOP value will fluctuate within a small range. Moreover, the NOP fluctuates with the increase of the crankshaft speed, in a small range. When the crankshaft speed reaches a critical value, the NOP begins to reduce significantly.