Hot Selling Fuel Injector Actuator Control Solenoid Valve for 0 445 110 Engine Parts for Volvo Injector

The injector solenoid valve is the core driving component of the electromagnetic injector. It controls the opening and closing of the valve core (needle valve) through electromagnetic force to achieve precise fuel injection. It is widely used in gasoline engines, small and medium-power diesel engines and some alternative fuel engines. Its performance directly affects the injection timing, injection volume and atomization effect, and is a key actuator of the engine electronic control system. The following is an introduction from the structural composition, working principle, core characteristics and technical points:

Core structural composition
The injector solenoid valve needs to work stably under high frequency (opening and closing dozens to hundreds of times per second) and high pressure (fuel pressure 3-200MPa) environment. The structure is precise and highly integrated, mainly including:

Electromagnetic coil: It is made of enameled copper wire (diameter 0.05-0.1mm) tightly wound (hundreds to thousands of turns). It generates a magnetic field when powered on and is the source of electromagnetic force. The coil resistance is usually 1-10Ω (1-3Ω for low resistance type, 5-10Ω for high resistance type), and needs to match the driving current of the ECU (peak current of low resistance type is 10-15A, and peak current of high resistance type is 2-5A).
Armature: The magnetic metal part (mostly low carbon steel or iron-nickel alloy) located inside the coil can be magnetized by the magnetic field and generate attraction, directly or indirectly pushing the valve core to move. The connection between the armature and the valve core is divided into rigid connection (integrated) and elastic connection (through push rod or spring transition), the latter can buffer the impact and extend the service life.
Yoke (housing): The magnetic shell surrounding the coil forms a closed magnetic circuit to enhance the magnetic field strength, and at the same time plays the role of fixing and protecting the internal parts. The material is mostly high magnetic permeability cast iron or alloy steel.
Reset spring: Installed between the armature and the yoke, when the coil is powered off, the spring force pushes the armature and the valve core to reset and close the injection channel. The spring stiffness needs to be precisely designed (elastic force 5-15N) to ensure that the valve core closes quickly (closing time ≤0.2ms).
Insulation: The insulating material between the coil and the yoke and armature (such as polyimide film) must withstand the 12-24V working voltage and the high temperature of the engine compartment (-40℃ to 150℃) to prevent short circuit or leakage.

Working principle
The working process of the injector solenoid valve is based on the linkage mechanism of "electromagnetic induction-force conversion-mechanical movement" and can be divided into three stages:

Opening stage: ECU sends a fuel injection signal, the electromagnetic coil is energized → the coil generates a magnetic field, the yoke and armature form a closed magnetic circuit → the armature is subjected to an upward electromagnetic force, overcoming the resistance generated by the return spring elastic force and the fuel pressure → the armature drives the valve core to move upward, the valve core is separated from the valve seat, and the fuel is sprayed out through the spray hole.
Holding stage: The coil is continuously energized, and the electromagnetic force maintains the open state of the armature and the valve core. At this time, the required current is lower than the peak current (about 1-2A for high resistance type and about 3-5A for low resistance type) to prevent the coil from overheating.
Closing stage: ECU stops signal output, the coil is powered off → the magnetic field disappears, the electromagnetic force returns to zero → the reset spring pushes the armature and the valve core downward to reset, the valve core fits tightly with the valve seat, the fuel passage is cut off, and the injection ends.

The whole process needs to be completed in a very short time (single injection duration 0.5-20ms), and the opening and closing delay needs to be controlled within 0.3ms to match the combustion rhythm in the cylinder of the engine (such as about 50 injections per second when the four-cylinder engine is idling).

Core performance indicators
The performance of the solenoid valve directly determines the control accuracy of the injector. The key indicators include:

Response speed: "opening delay" (≤0.3ms) from the ECU signal to the full opening of the valve core and "closing delay" (≤0.2ms) from power failure to full closing. Excessive delay will cause the injection time to shift and affect the combustion efficiency.
Electromagnetic force stability: The electromagnetic force error under the same current must be ≤5%, otherwise it will cause differences in the injection amount of different injectors (the error must be ≤3%), causing uneven operation of each cylinder of the engine.
Fatigue resistance: It must withstand more than 10⁸ opening and closing cycles (equivalent to a 100,000-kilometer service life of a passenger car), and the coil insulation layer and spring must not age or break.
Anti-interference ability: It must resist electromagnetic noise in the engine compartment (such as the ignition system and motor) to avoid malfunction; at the same time, the electromagnetic radiation generated by itself must comply with the vehicle EMC standards (such as ISO 11452).

Technology development trend
In order to meet the "high efficiency and low carbon" requirements of the engine, the injector solenoid valve is upgrading in the following directions:

High speed: By optimizing the coil winding process (such as tight winding of flat wire) and magnetic circuit design (reducing magnetic leakage), the opening delay is shortened to less than 0.15ms, supporting more precision injections (such as pre-injection and post-injection).

Miniaturization: Reduce the volume to adapt to the compact cylinder head design (such as the side injector of the direct injection gasoline engine), while reducing the armature mass (using light alloy) and reducing the inertia of movement.

Integration: Integrated design with the valve core and sensor (such as position feedback sensor) to form an "intelligent solenoid valve" to achieve closed-loop control (real-time correction of the opening and closing time through the ECU), and further improve the injection accuracy to within ±1%.

In summary, the injector solenoid valve is the "switch core" of the electronic fuel control system. Its performance balances cost and control accuracy. It will continue to dominate the field of small and medium-power engines for a long time, and continue to meet higher emission and efficiency requirements through technological iteration.