BS ISO 12251 pdf download Diesel engines — Clamp mounted CR fuel injectors — Mounting dimensions
This International Standard specifies dimensional requirements for clamp mounted CR fuel injectors and their corresponding cylinder head features in diesel engines.
According to the injector nozzle capnut, the clamp mounted CR fuel injectors can be divided into two types:
a) Type A, where the nozzle capnut is straight (see Figure 4).
b) Type B, where the nozzle capnut is stepped (see Figure 5).
Each clamp mounted CR fuel injector type is subdivided by a series of different sizes.
NOTE This differentiation corresponds to the relationship between the two guide diameters of the clamp mounted CR fuel injectors.
For the purposes of this document, the following symbols apply:
D 1 = injector shaft diameter
D 2 = injector upper guide diameter
D 3 = capnut diameter
D 4 = injector lower guide diameter
D 5 = injector nozzle shaft diameter
d 6 = bore for upper guide diameter
d 7 = bore for lower guide diameter
d 8 = bore for nozzle shaft
l 1 = overall injector length
l 2 = distance between sealing face and upper guide diameter of injector
l 3 = overlapping (upper guide diameter/cylinder head)
l 4 = injector clamping width
l 5 = clamp width
l 6 = injector clamping height
l 7 = distance between sealing face and datum B on injector
l 8 = distance between sealing face and datum C on injector
NOTE l 7 and l 8 are dependent on the cylinder head design as agreed between injector manufacturer and customer.
3 General requirements
3.1 Clamp mounting arrangement
A typical clamp mounting arrangement is shown in Figure 1 (schematically).