Abstract: A fuel additive system of a fuel delivery system of a vehicle includes an additive tank assembly, and a dosing unit in communication with the additive tank assembly to control the amount of additive dosed to the fuel tank. The additive tank assembly includes a pressurized tank of generally torispherical or ellipsoidal shape, a tank conduit with one end in communication with a sump in the pressurized tank and an opposite end extending out of the pressurized tank, and a valve in communication with the tank conduit near the opposite end thereof and being normally closed under pressure from the pressurized tank. The dosing unit includes a housing having an inlet passage in communication with the tank conduit, and a valve actuator in the inlet passage to displace the valve of the additive tank assembly to an open position once the dosing unit is assembled to the additive tank assembly.