About DENSO Common rail injector adjust

                     Denso G2

1、Armature lift 

1）Definition： The removable distance of the half ball during the working process of the fuel injector, The setting value for Denso G2 injectors is generally between 45μm to 55μm.

2）Sketch：

3）Adjusting trend: The thicker the shim is, the longer the lift.

4）Influence on fuel injection characteristics: In normal range, the longer the lift, the larger the fuel injection.  The most obviously influence is on the pre-injection point and full load point oil.

2、Air clearance

1）Definition： When the solenoid valve is electrified, armature plate was moved to the upper location under the traction of the electromagnetic, now there is no direct contact between armature plate and electromagnetic valve plane, but it has a certain gap, the gap is called air clearance. The air clearance range of the Denso G2 injector is generally between 45 and 55μm..It does not need to be adjusted, it is controlled by production and processing.

2）Sketch：

The armature plate of Denso G2 injector has a convex circle, when the electromagnet is electrified, the convex circle contact with the electromagnet, The gap between the armature plate and the electromagnet is called air clearance. As shown in the picture below:

3、Needle lift

1）Definition：When the injector is working, the needle will move to achieve the start and the end of the injection. The movement is called needle lift.

2）Sketch：

3)Adjusting trend：Change the length of the pressure top lever will adjust the range of the needle valve lift. The longer the top lever, the weaker the lift.

4)Influence on oil injection characteristics： Due to the Denso G2 injector needle valve lift is large, the ballistic area of the injection curve is further back, polarization time and full load point (pulse width) is generally less than 1500 microseconds, so the needle valve lift process has limited impact on the fuel injection quantity. But in general, the stronger the needle valve lift, the more the fuel injection.

4、Solenoid valve spring force

1)Definition: The solenoid valve spring has a preset force, which is used to compress the seal ball tightly to seal the high-pressure fuel in the seat control chamber. The solenoid valve spring force cannot be too weak, otherwise the high pressure fuel will leak out from the seat surface. It can't be too strong either, otherwise the ball will open slowly or even can’t be opened. The preset force range of

The electromagnetic valve spring of the Denso G2 injector is from 55N to 80N.

2) Sketch:

3）Adjusting trend：The thicker the shim is, the stronger the spring preset force.

4）Influence on oil injection characteristics:  The stronger the spring preset force，The less the injection quantity. Especially it has obvious influence on the medium - speed point (emission point)

5、Nozzle spring force

1)Definition：The nozzle spring has a preset force, which is used to tighten the needle valve to seal the hole to prevent fuel injection. The oil nozzle spring force cannot be too weak, otherwise the oil nozzle will have fuel leakage. It can't be too strong either, or the needle valve will open slowly. The nozzle spring preset force of Denso G2 injector is from 15 N to 35 N.

The nozzle spring gauge is used to adjust the preset force of the nozzle spring.

2）Sketch：As the picture above

3）Adjusting trend：The thicker the shim is, the stronger the spring preset force.

4）Influence on oil injection characteristics: The stronger the spring preset force，The less the injection quantity.