PCT No. PCT / DE98 / 02771 Sec. 371 Date Jul. 23, 1999 Sec. 102(e) Date Jul. 23, 1999 PCT Filed Sep. 18, 1998 PCT Pub. No. WO99 / 20893 PCT Pub. Date Apr. 29, 1999A fuel injection system having a common rail pressure reservoir filled with high-pressure fuel and having a dual-fuel injector for a bi-fluid injection of fuel and an additive fluid into an internal combustion engine. The system includes a first 2 / 2-way valve in the injection line between the common rail pressure reservoir and a pressure chamber encompassing the injector needle of the dual-fuel injector as well as a second 2 / 2-way valve, whose inlet is connected via a supply line to the injection line at a point between the first 2 / 2-way valve and the pressure chamber, and whose outlet is connected to the low-pressure fuel side by way of an outlet line. As a result, the otherwise conventional 3 / 2-way solenoid control valves, which are significantly more complex technically, can be replaced by more reasonably priced 2 / 2-way valves. At the same time, this raises the possibility of shifting the quantity metering for additive fluid to a single metering valve that serves an entire group of injectors.