Abstract: An automated control system for a dual-fuel boiler, engine, or other apparatus continuously monitors the consumption of a primary fuel source and automatically switches from the primary fuel source to a secondary fuel source when a predetermined amount of the primary fuel is used in a measured time period, the object of the system being to automatically maintain a 100% load factor of the primary fuel source. A meter continuously monitors consumption of the primary fuel and outputs an electronic flow signal representing consumption of primary fuel. The flow signal is received by a programmable logic controller having a real-time clock whereby consumption of the primary fuel is measured against time. Remote control actuated ball valves mounted in the primary and secondary fuel lines selectively control the flow of primary and secondary fuels to the dual-fuel apparatus.

Abstract: A supplemental gaseous fuel system is provided for retrofit to an existing diesel engine having a conventional load sensitive speed control. The supplemental gaseous fuel system operates independently of the load sensitive speed control thus enabling the diesel fuel supply system to rapidly react to load transients. A control system senses a physical position of an actuator mechanism in the diesel fuel injector pump and opens and closes a buffer valve in response to predetermined positions of the actuator. In normal operation of the engine, variations (increases) in engine load are initially corrected for by an immediate but momentary increase in diesel fuel to the engine. However, as soon as the engine has responded to the increase in diesel fuel and increased its rate of combustion, the gas flow to the engine is increased and causes the diesel fuel actuator to approach a minimum fuel setting.