Multi-fuel injector with fuel mixing

A fuel injection method, comprising:

• supplying a pilot fuel to a nozzle of a fuel injector;
• supplying a primary fuel to the nozzle, the pilot fuel being different than the primary fuel;
• at least partially mixing the pilot fuel and the primary fuel in the nozzle before either the primary fuel or the pilot fuel is injected with the nozzle;
• and
• injecting the pilot fuel and the primary fuel through a single set of openings in the nozzle.

A fuel injection system, comprising:

• a first common rail configured to receive a pilot fuel;
• a second common rail configured to receive a primary fuel;
• and
• a fuel injector having:
• a nozzle;
• a check valve member extending within the nozzle;
• a primary fuel path configured to supply a primary fuel to the nozzle;
• and
• a pilot fuel path within the fuel injector configured to supply a pilot fuel to openings in the nozzle, the primary fuel path being fluidly connected to the pilot fuel path when the check valve member is in a closed position that prevents injection of the pilot fuel and injection of the primary fuel.