Fuel Injector Parts

Fuel injectors are a key component of electronic fuel injection engines. Receiving commands from the Electronic Control Unit (ECU), they precisely control the timing, flow rate, pressure, and atomization of fuel injection, directly determining the engine's power output, fuel economy, and emissions levels. Fuel Injector Parts are widely used in various internal combustion engine fields, including automobiles, construction machinery, and marine power.

Working Principle

The core working principle of Fuel Injector Parts is precise electromagnetic drive control:

1. Standby state: When there is no control signal, the return spring inside the fuel injector remains in a compressed state, tightly pressing the needle valve against the injection hole. The valve is completely closed, effectively preventing fuel leakage and ensuring that the fuel system maintains a stable pressure.

2. Injection execution: When the ECU issues an injection command based on the engine's operating conditions (such as idle speed, acceleration, or load changes), the electromagnetic coil is instantly energized to generate a strong magnetic field. The magnetic field's suction force overcomes the resistance of the return spring, lifting the needle valve and opening the injection hole. High-pressure fuel oil (with a pressure of up to 2200-2500 bar) is ejected at high speed through the tiny annular gap between the shaft needle at the head of the needle valve and the spray hole. Under the action of the airflow, it is broken into micron-sized mist oil droplets and evenly distributed in the combustion chamber, creating conditions for complete combustion.

3. Injection Termination: After the ECU cuts off the current, the electromagnetic suction force rapidly disappears. The return spring drives the needle valve to quickly reset and close the injection hole, precisely terminating the injection process. The entire response cycle only takes 0.2 to 0.4 milliseconds, enabling high-frequency continuous injection and meeting the dynamic operating conditions of the engine.

Mainstream Product Types

1. Closed-Type Injector: 

Utilizing a closed valve seat structure, fuel only contacts the combustion chamber during injection, offering high reliability. Mainly divided into two types:

- Nozzle Type: The number of nozzles is adjustable from 1 to 10, with a diameter range of 0.15-1.0 mm. Fuel is directly injected into the combustion chamber through multiple nozzles, resulting in good atomization uniformity. Suitable for gasoline and diesel engines with direct injection combustion chambers, such as passenger cars and light trucks.

- Needle-type: A cylindrical needle extends from the needle valve head and inserts into the injection orifice, causing the fuel to be sprayed out in a ring-shaped mist with a wide atomization range, suitable for separate combustion chambers. Special derivative types include: throttling type (the needle head design enables pre-injection, reducing diesel engine noise), elongated orifice type (the needle valve is guided away from the hot zone to prevent jamming, suitable for high-speed, high-performance diesel engines), and forced cooling type (reducing heat load through cooling channels, used in large and medium-sized marine power plants).

2. Special Functional Injector Types

- Ball Valve Type: Uses a hollow, lightweight ball valve as the sealing element, featuring automatic centering, 40% better sealing performance than traditional needle valves, and faster response speed, suitable for high-pressure common rail systems.

- Plate Valve Type: Achieves stable reciprocating motion of the needle valve through a thin plate valve structure, reducing the risk of injection orifice clogging by 60%, extending maintenance intervals, suitable for engineering machinery applications with complex fuel quality requirements.

- Multi-hole type: Equipped with 4-12 precision nozzles, the fuel injection coverage is wider and the combustion is more complete. These Fuel Injector Parts are designed for high-performance direct injection diesel engines, such as heavy truck and construction machinery engines.