Supplemental fuel system for compression-ignition engine

A supplemental fuel system for a machine having a compression-ignition engine, the supplemental fuel system comprising:

• a supplemental fuel tank configured to store a supplemental fuel at a first pressure, the supplemental fuel configured to supplement a primary fuel used by the compression-ignition engine;
• a first pressure regulator configured to be positioned downstream of the supplemental fuel tank, the first pressure regulator configured to reduce the first pressure of the supplemental fuel received from the supplemental fuel tank to a second pressure;
• a second pressure regulator configured to be positioned downstream of the first pressure regulator, the second pressure regulator configured to reduce the second pressure of the supplemental fuel received from the first pressure regulator to a third pressure;
• a nozzle configured to be positioned (i) downstream of the second pressure regulator and (ii) within a conduit of an air supply system for the compression-ignition engine, the nozzle configured to receive a flow of the supplemental fuel and provide the supplemental fuel to air flowing though the conduit, wherein the nozzle has a body defining a first inlet positioned at a first nozzle end thereof, an outlet positioned at an opposing second nozzle end thereof, a second inlet positioned between the first nozzle end and the opposing second nozzle end, and a nozzle passage extending from the first nozzle end to the opposing second nozzle end that is configured to receive the air flowing through the conduit, wherein the nozzle passage has a non-uniform profile including a first transition point, a second transition point, an inlet taper extending from the first nozzle end to the first transition point, a mixing chamber positioned between the first transition point and the second transition point, and an outlet taper extending from the second transition point to the opposing second nozzle end, wherein the inlet taper is different than the outlet taper, wherein the second inlet is positioned along the mixing chamber, wherein the body has a first diameter of about 3 inches, the mixing chamber has a second diameter of about 2 inches, the body has a first length of about 4 inches, the inlet taper has a second length of about 0.5 inches, the mixing chamber has a third length of about 2 inches, and the outlet taper has a fourth length of about 1.5 inches, an electronic lock off valve configured to be positioned between the supplemental fuel tank and the nozzle;
• and
• a controller configured to control the electronic lock off valve to selectively disengage the supplemental fuel system and prevent the supplemental fuel from being provided to the air flowing through the conduit.