5 Common Failure Modes of Injector Nozzles

With the rapid development of new energy technologies in the future, the technology of high-pressure common rail diesel vehicles is becoming more mature and sound. The key technology of piezoelectric ceramic chip high-pressure common rail is applied to more and more diesel locomotives. Due to the optical rotation and deformation characteristics of piezoelectric ceramic sheets, they have been quickly applied to high-pressure common rail fuel injection pumps. At this stage, piezoresistive fuel injection pumps are mainly used in some high-end diesel cars, such as the new Mercedes-Benz, BMW five series, and mark, Dongfeng Citroen, Land Rover Range Rover, etc.

Piezoelectric ceramics are made by subjecting piezoelectric profiles to high-temperature calculations under the necessary processing technology, followed by mechanical processing and manufacturing, burning silver electrical grades according to the necessary methods, and polarizing them with alternating voltage electrostatic fields. Crystal material, a kind of functional raw material with piezoelectric effect, is called a piezoelectric ceramic sheet because its production process is similar to that of porcelain production.
In the whole process of diesel vehicle maintenance, the piezoresistive fuel injection pump will cause different common failures and reflections due to different invalid methods. What are the common invalid methods of such piezoresistive fuel injection pumps? How does the car reflect the different invalid ways and what maintenance plan must be? Today, we must have a deep understanding together:

1. Particle wear on the sealing surface of the control valve core

Failure mechanism	There are a lot of hard particles in diesel, causing high-pressure sealing surface wear (oil, diesel filter or maintenance problems)
Vehicle response	Difficulty in starting, weakness, black smoke
Static test results	Large oil return, large full load point maybe
Repair plan	Replace the control valve plate, the control spool may also need to be replaced

2. Wear of the sealing seat surface of the control valve plate

Failure mechanism	There are a lot of hard particles in diesel, causing high-pressure sealing surface wear (oil, diesel filter or maintenance problems)
Vehicle response	Difficulty in starting, weakness, black smoke
Static test results	Large oil return, large full load point maybe
Repair plan	Replace the control valve plate, the control spool may also need to be replaced

3. Cavitation on the sealing surface of the control valve

Failure mechanism	The diesel contains water, and the water bubbles explode in the process of transforming from high pressure to low pressure, causing cavitation on the sealing surface
Vehicle response	Difficulty in starting, weakness, black smoke
Static test results	Large oil return, large full load point maybe
Repair plan	Replace the control valve plate and control spool

4. the seat surface of the oil inlet and outlet valve plate is worn

Failure mechanism	There are a lot of hard particles in diesel, causing high-pressure sealing surface wear (oil, diesel filter or maintenance problems)
Vehicle response	Difficulty in starting, weakness, black smoke
Static test results	Large oil return, large full load point maybe
Repair plan	Replace the inlet and outlet valve plates, the control valve plate and control spool may also need to be replaced

5. Carbon deposits in the nozzle hole

Failure mechanism	Carbon deposits in nozzle holes or blockage by particles
Vehicle response	Car power off
Static test results	The injection volume is too small, especially at the full load point
Repair plan	Special cleaning fluid ultrasonic cleaning nozzle or replacement nozzle

The above is a compilation of key points related to common failure modes of piezoelectric injectors. In the repair process of piezoelectric injectors, it is necessary to have a clear and accurate judgment on the wear status of the injector parts, so as to assess whether different parts need to be replaced, so as to achieve better precision maintenance. At the same time, it should be reminded that the disassembly and maintenance methods of Bosch, Denso, and Delphi piezoelectric injectors are not the same. We will continue to introduce you in detail in the future.