The fuel metering valve is a critical component in the fuel delivery system, ensuring precise control of fuel flow and injection volume. Its performance directly impacts the engine's combustion efficiency, power output, emissions, and operational stability. The following provides a detailed explanation of various aspects:
1. Core Function
The fuel metering valve's core function is to precisely regulate the amount of fuel entering the engine's combustion chamber based on engine operating conditions (such as speed, load, and temperature) and in accordance with instructions from the ECU (Electronic Control Unit). Specifically, it:

Ensures that fuel delivery matches engine requirements under various operating conditions (cold start, idling, acceleration, and high speeds), avoiding either excessively rich fuel (fuel waste and excessive emissions) or excessively lean fuel (lack of power and engine jitter).

Quickly responds to changing operating conditions, such as rapidly increasing fuel delivery during rapid acceleration, ensuring smooth power flow.

II. Operating Principle
Fuel metering valves typically consist of a solenoid actuator, a valve core, a valve seat, and a sensor feedback assembly (on some models). They operate based on the electromagnetic control principle:

The ECU calculates the required fuel quantity based on signals from engine sensors (crankshaft position sensor, air flow meter, throttle position sensor, etc.) and sends an electrical signal (such as a pulse-width modulated (PWM) signal) to the metering valve.

This electrical signal drives the solenoid coil to generate a magnetic field, which attracts the valve core and changes the cross-sectional area (i.e., the opening) of the passage between the valve core and the valve seat.

Fuel flows through the aperture-controlled passage into downstream systems (such as high-pressure fuel pumps or injectors), enabling precise flow regulation.

Some high-end models are equipped with a position sensor that provides real-time feedback on the valve core opening, forming a closed-loop control loop and further improving accuracy.

III. Application Scenarios
Fuel metering valves are widely used in various internal combustion engine-powered equipment and can be categorized by fuel type:

Gasoline engines: Typically integrated into the fuel pump or fuel rail, they control the fuel pressure and flow to the injectors. Diesel engines: Commonly found in high-pressure common rail systems, this device acts as an "injection metering unit" (IMV) installed at the high-pressure fuel pump inlet, controlling the amount of fuel entering the pump and, in turn, regulating the pressure within the common rail.

Other fuel systems, such as the gas metering valve in gas engines (natural gas and liquefied petroleum gas), operate on a similar principle, but use gas as the fuel medium.