A volume-control, Z the size of the nozzle opening and closing speed and the fuel injection process plays a decisive impact. Double hole in the valve body structure into three key oil hole to hole oil and the control room, their structure and size of the injector fuel injection performance enormous impact. Oil back into the hole and the fuel flow rate-the difference between the volume control room and the decision to open the nozzle needle speed, and speed the closure of the valve nozzle from the oil hole into the flow rate and volume control room decision. Hole-fuel nozzle needle should be designed so that there is sufficient closure speed, in order to reduce post-atomized spray nozzle bad part.

In addition the minimum injection pressure nozzle back on fuel oil into the hole and hole control the flow rate and the end of the Pistons. In determining that the fuel into the hole, back to the control room and fuel-size structure, the nozzle needle to determine the stability of completely open, the shortest injection process, the nozzle at the same time to determine the stability of the smallest injection . Volume control room so that the valve can be reduced faster response to temperature on the fuel injection nozzle of the impact of even smaller.

However, the control room could not unlimited volume reduction, it should be able to guarantee the nozzle needle so that the valve lift completely open. Two control of the decision-dynamic pressure in the control room to determine the movement of the needle, through careful regulation of the two hole discharge coefficient, can produce the ideal fuel injection law.