A method of reducing carbonaceous deposits on a fuel injector is provided in which a first fuel composition is supplied to the fuel injector in a dual fuel engine, the first fuel composition comprising natural gas fuel and a first percentage of diesel fuel; and a second fuel composition is supplied to the fuel injector in a dual fuel engine, the second fuel composition comprising a second percentage of diesel fuel that is greater than the first percentage of diesel fuel to cause cavitation to occur within the fuel injector, thereby reducing carbonaceous deposits.

Methods and systems for cleaning a capless refueling system in a vehicle are disclosed. In one example approach, a method comprises, in response to a leak detected following a refueling event, cleaning the capless refueling system using engine vacuum.

Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection of the liquid fuel based on a measured parameter associated with auto-ignition of end gases subsequent to the compression-ignition of the liquid fuel. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

An engine includes a cylinder internal pressure sensor, a torque sensor, and an engine control device. The cylinder internal pressure sensor detects a cylinder internal pressure. The torque sensor detects an engine load. The engine control device receives a detection result of the cylinder internal pressure sensor and a detection result of the torque sensor. If the load detected by the torque sensor is zero (no load) and the cylinder internal pressure obtained from the detection result of the cylinder internal pressure sensor is greater than or equal to a threshold, the engine control device determines that an abnormality occurs in detection by the torque sensor.

A method for detecting reverse flow for a dual fuel engine is disclosed. The engine may include an intake manifold, a liquid fuel supply line and a gaseous fuel supply line, the gaseous fuel supply line including a gaseous fuel supply and a gaseous fuel rail. The method may include: operating the dual fuel engine in a liquid fuel only mode via the liquid fuel supply line; determining a reverse flow in the gaseous fuel supply line; and outputting an indication of reverse flow in response to the determination of reverse flow.

An engine including a cylinder internal pressure sensor, a torque sensor, and an engine control device. The cylinder internal pressure sensor detects a cylinder internal pressure. The torque sensor detects an engine load. The engine control device receives a detection result of the cylinder internal pressure sensor and a detection result of the torque sensor. If the load detected by the torque sensor is zero (no load) and the cylinder internal pressure obtained from the detection result of the cylinder internal pressure sensor is greater than or equal to a threshold, the engine control device determines that an abnormality occurs in detection by the torque sensor.

A control circuit for a dual fuel generator includes a primary fuel valve to control the supply of a primary fuel, a secondary fuel valve to control the supply of a secondary fuel, a primary fuel pressure switch to detect the primary fuel, a secondary fuel pressure switch to detect the secondary fuel, and a controller. The controller is configured to receive a primary signal for availability of the primary fuel from the primary fuel pressure switch and a secondary signal for availability of the secondary fuel from the secondary and operate the primary fuel valve and the secondary fuel valve in response to the primary signal and the secondary signal. When the secondary fuel valve is open so that the secondary fuel is provided to the dual fuel generator, the control circuit is configured to ground the primary signal by connecting the primary fuel pressure switch to ground.

A technique for fuel system protection for an internal combustion engine comprises determining direct fuel injector temperature as a function of engine operating parameters; and advancing intake valve timing when the temperature rises above a first predetermined value such that the temperature is maintained below a second predetermined value.

A control system and method for a multi-fuel generator engine are mainly applied to multi-fuel generator products. The control system comprises a controller, a first signal input terminal, a second signal input terminal, a third signal input terminal, and an output terminal connected to an ignition device of a generator engine. When the third signal input terminal of the controller receives a generator engine start signal and either the first signal input terminal or the second signal input terminal receives a signal corresponding to an on state of the corresponding valve assembly, the controller controls the ignition device to ignite. According to control system and method, the controller detects signals corresponding to the states of the two fuel valve assemblies to determine whether or not fuels are normally supplied, so that operating instabilities or faults caused by synchronous supply of two fuels to the generator engine are avoided.

A control circuit for a dual fuel generator includes a primary fuel valve to control the supply of a primary fuel, a secondary fuel valve to control the supply of a secondary fuel, a primary fuel pressure switch to detect the primary fuel, a secondary fuel pressure switch to detect the secondary fuel, and a controller. The controller is configured to receive a primary signal for availability of the primary fuel from the primary fuel pressure switch and a secondary signal for availability of the secondary fuel from the secondary and operate the primary fuel valve and the secondary fuel valve in response to the primary signal and the secondary signal. When the secondary fuel valve is open so that the secondary fuel is provided to the dual fuel generator, the control circuit is configured to ground the primary signal by connecting the primary fuel pressure switch to ground.