In the event that a nozzle valve is stuck open in an EHI used in a common rail fuel system which of the following ensures that fueling to the effect of cylinder is limited?

• A. Rail pressure sensor
• B. Flow limiter valve
• C. Rail pressure regulator valve
• D. Unintended fuel sensor

Answer: (B)

When a nozzle valve sticks open in an electronic hydraulic injector within a common-rail system, the chance of delivering more fuel than the cylinder can safely use increases. The flow limiter valve is designed to cap the maximum fuel flow to the affected injector channel, so even if the nozzle valve remains open, the amount of fuel that can reach the cylinder is limited. This protects the engine from over-fueling and reduces the risk of damage. The rail pressure sensor only monitors pressure; it doesn’t actively stop fuel flow. The rail pressure regulator valve keeps rail pressure in check overall by returning excess fuel, but it doesn’t limit flow specifically to the malfunctioning injector. An unintended fuel sensor isn’t a mechanism that directly limits injector flow.