Methods and systems are described for a fuel system in an engine comprising two lift pumps. One example method comprises deactivating one of a first lift pump and a second lift pump if fuel fill level in a common reservoir decreases below a threshold fill level, wherein the first lift pump and the second lift pump are positioned in the common reservoir. By deactivating one of the two lift pumps, the two lift pumps may be protected from degradation due to fuel starvation.

A bi-fuel control system can include an electronic control module and a control unit that are in communication with each other. The system can include a first set of fuel injectors that are configured to deliver a primary fuel to an engine and can include a second set of fuel injectors that are configured to deliver a secondary fuel to the engine. The bi-fuel control system can operate in either a primary operational state in which the first set of injectors is used or a secondary operational state in which the second set of injectors is used. In either operational state, the electronic control module can control the respective set of injectors independently from the control unit.

A dual fuel system for a combustion engine includes an air and fuel mixer configured to mix air and fuel provided to the combustion engine, a first fuel path for a first fuel, and a second fuel path for a second fuel. The first and second fuels have different physical and chemical properties. The dual fuel system also includes a common fuel path coupled to the air and fuel mixer and both the first and second fuel paths, wherein the common fuel path includes an electronically controlled valve configured to regulate the air to fuel ratio of an air/fuel mixture provided to the combustion engine in response to control signals from a controller, and both the first and second fuel paths are coupled to the common fuel path at a location upstream of the electronically controlled valve.

In a control system for an internal combustion engine that can use a plurality of kinds of fuel including compressed natural gas, the invention prohibits a changeover from CNG to another fuel from being made in a period from a time when CNG is used for the first time after the start of the internal combustion engine to a time when it is determined that properties of CNG do not need to be learned, or a period from the time when CNG is used for the first time after the start of the internal combustion engine to a time when a processing of learning the properties of CNG ends.

The exemplary embodiments herein provide a dual fuel system with a recreational vehicle electric battery for use with a power generation assembly. The system comprises a combustion engine with a stator assembly for generating power and further having a gasoline pump, an LP shutoff valve, and a carburetor valve. The system further comprises a recreational vehicle battery, a DC rectifier in electrical communication with the stator assembly, a fuel selection switch, and a digital fuel valve control module (DFVCM). Multiple fuels are safely controlled while interchanging power between a battery and the DC rectifier.

A method includes determining an extent of usage of the internal combustion engine. The method includes comparing the extent of usage with a threshold value. In response to determining that the extent of usage is below the threshold value, the method includes operating the internal combustion engine under a first condition during which a lubricating oil in the internal combustion engine is combusted to form a combustion by-product. The method further includes operating the internal combustion engine under a second condition during which the combustion by-product is deposited onto components of the internal combustion engine.

Techniques and systems are described for power generation management. A described technique includes receiving, by a controller, a request to activate a power generator, wherein the power generator is fuel-based; receiving, by the controller, one or more sensor inputs from one or more sensors situated at or nearby the power generator; using, by the controller, the one or more sensor inputs to detect human activity around the power generator; and controlling, by the controller, an activation of the power generator in response to the request based on whether human activity is detected around the power generator.

The exemplary embodiments herein provide a dual fuel system with a recreational vehicle electric battery for use with a power generation assembly. The system comprises a combustion engine with a stator assembly for generating power and further having a gasoline pump, an LP shutoff valve, and a carburetor valve. The system further comprises a recreational vehicle battery, a DC rectifier in electrical communication with the stator assembly, a fuel selection switch, and a digital fuel valve control module (DFVCM). Multiple fuels are safely controlled while interchanging power between a battery and the DC rectifier.

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.

[Problem] To prevent an abnormality of an engine that may occur due to switching from a first fuel to a second fuel.

[Solution] The engine system 100 includes an engine 1 that is capable of switching between a first mode in which a first fuel is combusted and a second mode in which at least a second fuel out of the first fuel and the second fuel is combusted, a first fuel supplier 6 that supplies the first fuel to the engine 1, a second fuel injection device 43 that supplies the second fuel to the engine 1, an air-fuel ratio controller 23 that controls the air-fuel ratio, a controller 7 that controls the first fuel supplier 6, the second fuel injection device 43, and the air-fuel ratio controller 23, and an acceptor 92 that accepts an instruction for the controller 7. When the acceptor 92 accepts an instruction for transition from the first mode to the second mode, the controller 7 executes self-diagnosis of at least one of the first fuel supplier 6, the second fuel injection device 43, and the air-fuel ratio controller 23 while maintaining the operation in the first mode, and determines whether to transition to the second mode based on a result of the self-diagnosis.