A supplemental fuel system includes a supplemental fuel tank, an electronic valve, a temperature sensor, and a controller. The supplemental fuel tank is configured to store a supplemental fuel configured to supplement a primary fuel used by an engine. The electronic valve is configured to be positioned between the supplemental fuel tank and an air supply system for the engine. The temperature sensor is configured to acquire temperature data regarding a temperature of the engine. The controller is configured to control the electronic valve such that the electronic valve is (i) closed to prevent the supplemental fuel from being provided to the air supply system in response to the temperature being less than a temperature threshold and (ii) open or openable to permit the supplemental fuel to be provided to the air supply system in response to the temperature being greater than the temperature threshold.