The dosing valve/injector is a critical component within the DEF/AdBlue injection system of modern diesel engines equipped with Selective Catalytic Reduction (SCR) technology. Its primary function is to receive pressurized DEF fluid from the tank and precisely meter, atomize, and inject it into the hot exhaust gas upstream of the SCR catalyst. This injection enables the chemical reaction that converts harmful nitrogen oxides (NOx) into harmless nitrogen and water vapor, ensuring compliance with stringent emissions regulations. The valve operates under electronic control from the vehicle's Engine Control Unit (ECU). Upon receiving a signal, an internal solenoid or piezoelectric actuator opens, allowing pressurized DEF fluid to pass through a precision nozzle. The fluid is atomized into a fine spray upon injection into the exhaust stream. The timing, duration, and frequency of injection pulses are precisely calculated by the ECU based on engine load, exhaust temperature, and NOx sensor feedback to optimize the SCR reaction. This component is designed for use in motor vehicle manufacturing, specifically for diesel engines with SCR systems. It is a part-level component, not a complete system. The materials used include stainless steel for the body and internal parts, engineering plastics/polymers for seals and insulators, and copper alloy for solenoid windings. Key parameters include an operating pressure of 1.0–1.6 MPa, a flow rate of 0.5–5.0 L/min, a response time of ≤50 ms, dosing accuracy of ±2.5%, operating voltage of 12–24 V DC (ISO 16750-2), power consumption of 15–30 W, operating temperature of -40–85 °C (ISO 16750-4), fluid temperature of -10–50 °C, ingress protection of IP65–IP69K (IEC 60529), body material of 316L (ASTM A240), coil insulation class H (IEC 60085), and weight of 0.3–0.8 kg. These values are reference ranges and must be verified for the specific model and application. The component is not certified or compliant solely by listing these standards; they serve as procurement and verification references. For selection, consider engine size, dosing demand, and environmental conditions. Interfaces include electrical connectors and fluid ports. Verification questions should address actual operating conditions and compliance with relevant standards. Maintenance signals include reduced dosing accuracy or response time. Failure boundaries include operating outside specified pressure, temperature, or voltage ranges.
The dosing valve/injector is electronically controlled by the Engine Control Unit (ECU). When the ECU sends a signal, an internal solenoid or piezoelectric actuator opens, allowing pressurized DEF fluid to flow through a precision nozzle. The fluid is atomized into a fine spray as it enters the exhaust stream. The ECU calculates the timing, duration, and frequency of injection pulses based on engine load, exhaust temperature, and NOx sensor feedback to optimize the SCR reaction. This precise dosing ensures efficient NOx reduction while minimizing DEF consumption.
