Understanding BOSCH Common Rail Diesel Injectors

The BOSCH diesel injector family is an integral component of modern diesel engines, providing precision fuel delivery for efficient performance. These injectors are divided into categories based on their applications: passenger cars and light-duty engines or heavy-duty diesel engines. Below is a detailed introduction to each type.

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Detailed Introduction to CRI CRIN Injectors

CRI 1-13, CRI 1-14, CRI 1-16

These injectors feature a standard pilot valve with an anti-bounce element, ensuring stable and accurate operation. Key components include:

1. Shim for adjusting valve spring force.
2. Anchor bolt.
3. Retaining ring.
4. Anchor plate.
5. Shim for residual clearance adjustment.
6. Valve clamping screw.
7. Armature disc.
8. Shim for armature stroke adjustment.

CRI2.1

Electromagnetic injector with a standard pilot valve without an anti-bounce device:

1. Shim for adjusting residual clearance.
2. Shim for adjusting the valve spring force.
3. Anchor bolt.
4. Shim for adjusting armature stroke.
5. Core guide.
6. Valve clamping screw.

CRI 2-14
CRI 2-14 OHW
CRI 2-16

183 is from a Euro 4 engine: CRI 22, 1.3 Multijet, 1.6 Fiat, and 2.3 Fiat engines. These are the same engines but upgraded to Euro 5.

CRI 2-16 M2
CRI 2-18: Electromagnetic injector with a pressure-balancing pilot valve.
CRI 2-18 Armature stroke: 26-32 μm.

CRI 2-18-VCC
CRI 2-20

1. Shim for adjusting the valve spring force.
2. Anchor bolt.
3. Safety sleeve.
4. Safety washer.
5. Anchor plate.
6. Shim for adjusting residual clearance.
7. Valve clamping screw.
8. Armature disc.
9. Shim for adjusting armature stroke.

CRI 2-25

The nozzle needle is solid with a control valve, welded in two places: near the needle itself and near the valve stem.

They can come with an NCC sensor or without it.

CRI 3-16
Piezoelectric Indirect-Acting Injector:

• The deformation of the piezo element is utilized to actuate the pilot valve.
• A hydraulic amplifier, referred to as the communication module, converts the minimal elongation of the piezo stack into the required lift of the pilot valve.
• When the injector is turned off, fuel pressure naturally closes the pilot valve, effectively reducing static fuel leakage.
• A bypass channel accelerates the filling of the control chamber (CC), helping to minimize the nozzle closing delay (NCD).
• Reducing the NCD enhances the injector’s capability for multiple injections, improving overall performance.

CRI 3-18

CRI 3-20

CRI 3-27

CRIN1

CRIN2

Standard solenoid injector (for heavy-duty applications).

CRIN2-16

CRIN2-L

CRIN3-18

CRIN3-20-BL

CRIN3-L

CRIN3-22

CRIN3-25

CRIN4-21

High pressure is achieved in two stages:

1. The high-pressure pump delivers fuel to the rail at a maximum pressure ranging from 900 to 1200 bar, depending on the version.
2. The pressure is further increased by a booster inside the injector, reaching 2100–2500 bar.

There are two electromagnetic valves in use:

• The first valve controls the needle.
• The second valve controls the pressure booster.

The coordinated operation of the two solenoid valves allows for faster injection and improved spray formation.

CRIN4-27
CRIN14 S3

Below is the list of injector types for each model

Understanding diesel injectors is essential for repair specialists. For premium injector parts and tools, visit DieselStart.com.