A fuel injector includes a nozzle, and a nozzle check including a closing hydraulic surface. The fuel injector also includes a high pressure passage, a low pressure drain, a control passage, a check control chamber, and a valve seat. A relief passage is formed by at least one of an injector housing or a control valve in a control valve assembly. The control valve is movable among a rest position, a lifted injection position, and a lifted relief position where the high pressure passage connects to the relief passage. The control valve can be operated to selectively connect the high pressure passage to the relief passage to bleed fuel pressure to prevent over-pressurization. Related apparatus and methodology is also disclosed.

A fuel injector including a flow balanced injector needle seal is provided. The fuel injector includes a needle in a fuel passage of the fuel injector body. The needle moves longitudinally in the fuel passage to selectively stop and start fuel injection from the fuel passage. The fuel injector includes a check valve assembly that maintains pressurized fuel in the fuel passage and permits fuel flow out of the fuel passage in response to a fuel injection event. The needle seal is provided between the check valve assembly and a sleeve that extends around the proximal end of the needle. The needle seal includes multiple inlet orifices for receiving a fuel flow into the needle seal that are positioned relative to one another so that net lateral forces on the needle are effectively offset from one another.

A fuel injector includes a nozzle, and a nozzle check including a closing hydraulic surface. The fuel injector also includes a high pressure passage, a low pressure drain, a control passage, a check control chamber, and a valve seat. A relief passage is formed by at least one of an injector housing or a control valve in a control valve assembly. The control valve is movable among a rest position, a lifted injection position, and a lifted relief position where the high pressure passage connects to the relief passage. The control valve can be operated to selectively connect the high pressure passage to the relief passage to bleed fuel pressure to prevent over-pressurization. Related apparatus and methodology is also disclosed.