a second hydraulic area disposed to urge the needle to the closed position when the second hydraulic area is exposed to fuel under pressure and valving coupled to the source of high pressure fuel and a vent to controllably couple the hydraulic area of the needle control member to the high pressure fuel or to the vent application_number US 71730007 A description diesel injectors with independent control of needle valve opening and closing velocity with a simple low cost design are disclosed as shown in fig1 the main components of the new injectors are a high pressure fuel supply reservoir 2 an electromagnetically actuated 3 way control valve 3 a needle control volume 4 a needle pin 6 a needle spring 7 a needle 8 a fuel volume around the needle 9 a vent volume 14 essentially at ambient pressure and a check disk 15 a hydraulic line 13 connects the reservoir 2 with the fuel volume 9 around the needle 8 the needle control valve has 3 ports the supply port 11 is connected to the supply reservoir 2 through hydraulic line 1 the control port 10 is connected to the needle control volume 4 through a hydraulic line 5 and the check disk 15 and the vent port 12 is connected to the vent 14 the needle control valve has a supply and a vent position and is normally when not energized in the supply position as.