A method of controlling a dual fuel engine configured to receive a first fuel and a second fuel includes operating the engine using the first fuel, measuring a current load of the engine, sending a first signal to a first fuel system to deliver an amount of the first fuel to the engine, and determining at least one first operating parameter associated with the engine. The method also includes determining an engine load estimate based on the first signal and the at least one first operating parameter, comparing the engine load estimate to the measured load, and based on the comparison, determining, an adjusted engine load estimate to compensate for a drift in the first fuel system.

A supplemental fuel system for a machine with an engine is configured to monitor a voltage of a power supply of the machine based on voltage data acquired by a voltage sensor where the power supply is configured to receive power from an alternator driven by the engine, compare the voltage to a voltage threshold, and control an electronic lock off valve positioned between a supplemental fuel tank and an air supply system for the engine such that the electronic lock off valve is (i) closed to prevent a supplemental fuel from being provided from the supplemental fuel tank to the to the air supply system in response to the voltage being less than the voltage threshold and (ii) open or openable to permit the supplemental fuel to be provided to the air supply system in response to the voltage being greater than the voltage threshold.

A fuel system for a machine with an engine is configured to monitor a voltage of a power supply of the machine based on voltage data acquired by a voltage sensor where the power supply is configured to receive power from an alternator driven by the engine, compare the voltage to a voltage threshold, and control an electronic lock off valve associated with a fuel tank such that the electronic lock off valve is (i) closed to prevent a fuel from being provided from the fuel tank to the to the engine in response to the voltage being less than the voltage threshold and (ii) open or openable to permit the fuel to be provided to the engine in response to the voltage being greater than the voltage threshold.

A method of controlling a dual fuel engine configured to receive a first fuel and a second fuel includes operating the engine using the first fuel, measuring a current load of the engine, sending a first signal to a first fuel system to deliver an amount of the first fuel to the engine, and determining at least one first operating parameter associated with the engine. The method also includes determining an engine load estimate based on the first signal and the at least one first operating parameter, comparing the engine load estimate to the measured load, and based on the comparison, determining, an adjusted engine load estimate to compensate for a drift in the first fuel system.