New High Quality Diesel Nozzle M0005P153 for Injection Nozzle Diesel Engine Parts

The injector nozzle (i.e., the injector nozzle) is the core executive component of the injector, and its performance directly affects the fuel atomization effect, combustion efficiency, and engine power. The following is a detailed analysis from the aspects of structure, classification, working principle, common faults, and maintenance:

Structure and function of the injector nozzle

1. Core structure
Spray hole assembly: It consists of a valve needle, a valve seat, and a spray hole plate. The spray hole diameter is usually 0.1~0.5mm (the direct injection nozzle in the cylinder can be as fine as 0.1mm or less), which determines the atomization particle size and cone angle of the fuel injection.

Sealing component: The sealing cone surface of the valve needle and the valve seat (usually hardened, with a hardness of HRC60+) ensures that the fuel does not leak when not spraying.

Driving mechanism: The electromagnetic coil or piezoelectric crystal drives the valve needle to reciprocate and control the opening time and frequency of the spray hole.
2. Main functions
Precise fuel metering: According to the ECU signal, by controlling the valve needle opening time (injection pulse width), the injection amount control of 0.1ms level (such as a single injection amount of 5~100mg) is achieved.
Efficient atomization of fuel: Using the throttling effect when the fuel high pressure (3~5bar for manifold injection, 50~350bar for direct injection in the cylinder) passes through the spray hole, the fuel is broken into 10~50μm oil mist and mixed with air to form a uniform mixture.

2. Classification and characteristics of injector nozzles
Classification method Type Structural characteristics Application scenarios
By injection position Manifold injection nozzle The spray hole faces the intake manifold, the pressure is low (3~5bar), the spray hole diameter is 0.3~0.5mm, and most of them are single-hole or multi-hole direct injection. Traditional electronic fuel injection engine (such as naturally aspirated models)
Direct injection nozzle in the cylinder Extend into the combustion chamber, the pressure is as high as 50~350bar, the spray hole is conical or multi-hole (6~12 holes), and the spray angle and shape need to match the combustion chamber design. Direct injection engine in the cylinder (such as turbocharged models)
According to the spray hole form Single-hole nozzle Single spray hole, the spray is conical, commonly used in early manifold injection, and the atomization uniformity is poor. Economy model, old engine
Multi-hole nozzle Multiple spray holes (3~12 holes), the spray is fan-shaped or annular, the coverage area is large, and the atomization is finer (such as the number of holes of the direct injection nozzle in the cylinder can reach 8~10). Direct injection in the cylinder, high-performance engine
According to the driving method Electromagnetic nozzle The electromagnetic coil drives the valve needle, the response time is 5~10ms, the cost is low, and it is suitable for medium and low injection pressure scenarios. Manifold injection, early direct injection
Piezoelectric nozzle Piezoelectric crystal stack drive, response time < 1ms, can achieve multiple injections (such as pre-injection + main injection + post-injection), with higher precision. High-end direct injection engines (such as BMW B series, Audi FSI)

Working principle of injector nozzle
Take electromagnetic injector nozzle as an example, its working process is as follows:

Non-injection state: the electromagnetic coil is powered off, the valve needle presses the valve seat under the action of the reset spring and fuel pressure, the spray hole is closed, and the fuel does not leak.
Injection process:
ECU sends an electric pulse signal, the electromagnetic coil is powered on to generate a magnetic field, attracting the armature to drive the valve needle to move up, and the spray hole is opened;
High-pressure fuel is sprayed out through the spray hole, and atomized into oil mist due to the throttling effect;
When the electric pulse ends, the coil loses magnetism, and the valve needle resets under the action of the spring force to close the spray hole.
Fuel injection quantity control: The longer the nozzle opening time (pulse width) is, the greater the fuel injection quantity (e.g., the fuel injection quantity is about 10mg when the pulse width is 2ms, and about 50mg when the pulse width is 10ms).

Common faults and causes of fuel injector nozzles

1. Spray hole blockage

Phenomenon: reduced fuel injection quantity, poor atomization, weak engine acceleration, idle jitter, and excessive emissions (HC, CO increase).

Cause:
The fuel contains impurities (such as rust, colloid) or high sulfur content, generating sulfides deposited in the spray hole;

When idling or driving at low speed for a long time, the fuel evaporates to form colloid to block the pores (especially the 0.1mm level spray hole for direct injection in the cylinder).

2. Failure of valve needle and valve seat seal

Phenomenon: fuel dripping at idle speed, fuel seeping into the cylinder after shutdown, causing "flooding", and the engine is difficult to start or emits black smoke.
Cause:
Fuel impurities scratch the sealing cone surface, or high temperature causes the valve seat to deform (the direct injection nozzle in the cylinder is subjected to high temperatures above 300℃ for a long time);
Frequent starting and stopping causes the valve needle to repeatedly hit the valve seat, causing wear (such as high-frequency use scenarios such as taxis).
3. Valve needle stuck
Phenomenon:
Stuck in the open state: continuous fuel injection, the engine cannot be turned off, and "backfire" may be caused;
Stuck in the closed state: the corresponding cylinder does not spray fuel, starting is difficult or idling is unstable.
Cause:
Poor fuel quality, carbon deposits or glue attached to the valve needle guide hole;
Poor cooling causes the valve needle to overheat and deform (such as improper installation of the heat sink).
4. Spray hole wear and expansion
Phenomenon: The amount of fuel injection increases, the mixture is too rich, the fuel consumption increases by 10%~20%, and the exhaust has a strong gasoline smell.
Cause: High-pressure fuel flushes the spray hole for a long time (such as 350bar pressure for direct injection in the cylinder), or hard particles in the fuel wear the edge of the spray hole.

Maintenance and care of injector nozzles
1. Daily use recommendations
Use high-clean fuel: Choose fuel from regular gas stations, avoid using fuel with excessive sulfur content (national VI standard fuel sulfur content ≤10ppm), and reduce sulfide deposition.
Replace fuel filters regularly: It is recommended to replace every 20,000 to 40,000 kilometers (adjusted according to fuel quality) to prevent impurities from entering the nozzle.
Avoid long-term idling: The fuel atomization is poor at idling, and carbon deposits are easily formed on the nozzle head. It is recommended to increase the speed (above 3000rpm) appropriately after driving for a period of time (such as 30 minutes) to flush the carbon deposits.
2. Professional cleaning and testing
Ultrasonic cleaning: Ultrasonic cleaning of the nozzle every 40,000 to 60,000 kilometers (using a special cleaning agent) to remove carbon deposits and colloids and restore the patency of the spray hole.
Flow matching test: Use an injector cleaning tester to detect the consistency of the injection amount of each nozzle (the deviation should be ≤5%) to avoid engine shaking due to uneven injection amount.
Pressure test: Check the fuel pressure holding capacity when the nozzle is closed (normally, the pressure should decay ≤10% within 5 minutes after shutdown) to judge the sealing performance.
3. Key points for fault prevention
When abnormalities such as engine shaking and weak acceleration are found, use the OBD diagnostic instrument to read the fault code (such as "inconsistent injector flow" and "misfire") in time to avoid the expansion of the fault.
Diesel vehicles need to pay extra attention to the water content of the fuel and regularly discharge the water in the fuel filter to prevent electrochemical corrosion of the valve seat.

Typical case: Clogged direct injection nozzle in the cylinder
Vehicle type: A 2.0T direct injection engine sedan, which experienced acceleration setbacks and increased fuel consumption after driving 80,000 kilometers.
Detection:
OBD reads fault code "P0300 multi-cylinder misfire";
Using a fuel pressure gauge to detect, the fuel rail pressure is normal (150bar) at idle, but after shutdown, the pressure drops from 150bar to 50bar within 30 seconds (normally it should be maintained for more than 5 minutes);
Disassembling the injector nozzles found that the nozzle holes of the 3 cylinders were blocked by black carbon deposits, and the other cylinders also had varying degrees of carbon deposits.
Reason: Long-term use of inferior fuel, excessive sulfur content, and the sulfide generated after combustion mixed with carbon deposits to block the spray holes.
Solution: Replace 4 injector nozzle assemblies, clean the fuel rail, use fuel system cleaner (containing PEA) to run 3 tanks of fuel, and the fault is eliminated.