Systems, methods, and apparatus for operation of dual fuel engines

A method, comprising:

• operating a dual fuel engine on 100% liquid fuel, and determining an engine load value;
• determining an expected fuel flow rate in response to a nominal substitution rate, a load substitution description, and the engine load value, wherein the expected fuel flow rate comprises a fuel rate for a second fuel and a resulting fuel rate for a first fuel, and wherein the load substitution description comprises a replacement amount of the second fuel that provides an amount of torque equivalent to a replaced amount of the first fuel;
• operating the dual fuel engine at a partially substituted operating condition wherein a a portion of the first fuel is substituted with the replacement amount of the second fuel;
• and
• comparing one of:
• the resulting fuel rate of the first fuel to the expected fuel flow rate and an effective fuel flow rate of the second fuel to the replacement amount of the second fuel;
• and
• adjusting the nominal substitution rate in response to the comparing.

A system, comprising:

• a dual fuel engine operable with a first fuel and a second fuel;
• and
• a controller operable connect to the duel fuel engine, the controller including:
• an engine output definition module structured to operate the dual fuel engine at one of an increased fuel fraction of the first fuel and a 100% fuel fraction of the first fuel, and to determine an engine load value;
• a fuel energy definition module structured to determine an expected fuel flow rate in response to a nominal substitution rate, a load substitution description, and the engine load value, wherein the expected fuel flow rate comprises a fuel rate for the second fuel and a resulting liquid fuel rate for the first fuel, and wherein the load substitution description comprises a replacement amount of second fuel that provides an amount of torque equivalent to a replaced amount of the first a fuel;
• a fuel check module structured to operate the dual fuel engine at a partially substituted operating condition wherein a portion of the first fuel is substituted with the replacement amount of the second fuel;
• a fuel energy quality module structured to compare one of:
• the resulting fuel rate of the first fuel to the expected fuel flow rate and an effective fuel flow rate of the second fuel to the replacement amount of the second fuel;
• and
• a fuel energy correction module structured to adjust the nominal substitution rate in response to the comparing.