Premixed engines including dual fuel engines can experience abnormal combustion characteristics including misfire, pre-ignition and knock. A method for detecting and mitigating abnormal combustion in an engine comprises sensing frequency components of an acoustic signal associated with a combustion chamber during a combustion cycle, the frequency components representative of at least one of a normal and an abnormal combustion characteristic; determining an in-cylinder pressure signal as a function of the acoustic signal; calculating as functions of the in-cylinder pressure signal at least one of a knock index, a gross indicated mean effective pressure and a start of combustion timing; detecting the abnormal combustion characteristic is at least one of (a) a misfire event when the gross indicated mean effective pressure is less than a predetermined mean effective pressure value; (b) a pre-ignition event when the start of combustion timing is advanced of a start of ignition timing; and (c) an engine knock event when the knock index is greater than a predetermined knock value; and performing a mitigation strategy for the detected abnormal combustion characteristic.

Various systems and methods are provided for identifying cylinder misfire. In one example, cylinder misfire may be identified based on a misfire monitor that differentiates a single-cylinder misfire event from a multi-cylinder misfire event based on output from a crankshaft speed sensor.

A method for controlling a dual fuel engine system includes determining a friction power loss amount of an internal combustion engine of the dual fuel engine system, where the friction power loss amount is based on an engine speed of the internal combustion engine and a friction torque estimate. The method also includes determining an accessory power loss amount of a power of the internal combustion engine, where the accessory power loss amount is based on the engine speed and an accessory torque estimate. The method further includes estimating a net engine power amount based on the accessory power loss amount and a brake power amount of the internal combustion engine, estimating an indicated diesel power, and estimating, based on the estimated net engine power, a first indicated engine power and a first gas power.

A system for remotely monitoring and controlling operation of a hydro-diesel engine, having: (a) a diesel engine assembly; (b) a hydro-diesel assembly connected to the diesel engine assembly; (c) a remote control system; and (d) a remote computer system in communication with the remote control system, wherein the remote computer system is configured to instruct the remote control system to turn off operation of either: (i) the hydro-diesel assembly while permitting the diesel engine assembly to continue operation while the hydro-diesel assembly is not operating, or (ii) both the hydro-diesel assembly and the diesel engine assembly.

A fuel tank containing a fuel and oil mixture is managed to determine if the fuel and oil mixture contains the correct ratio for a motor. The fuel tank containing a fuel and oil mixture is monitored. A fuel to oil ratio is selected for the motor. A combined viscosity of the fuel and oil mixture is calculated with respect to the fuel to oil ratio, and the temperature of the fuel and oil mixture. The combined viscosity is used to determine a predetermined range of the combined viscosity. The viscosity of the fuel and oil mixture within the fuel tank is measured as a measured viscosity. If the measured viscosity of the fuel and oil mixture does not correspond with the predetermined range, then a user may be alerted that the measured viscosity does not correspond with the predetermined range.

A fuel tank containing a fuel and oil mixture is managed to determine if the fuel and oil mixture contains the correct ratio for a motor. The fuel tank containing a fuel and oil mixture is monitored. A fuel to oil ratio is selected for the motor. A combined viscosity of the fuel and oil mixture is calculated with respect to the fuel to oil ratio, and the temperature of the fuel and oil mixture. The combined viscosity is used to determine a predetermined range of the combined viscosity. The viscosity of the fuel and oil mixture within the fuel tank is measured as a measured viscosity. If the measured viscosity of the fuel and oil mixture does not correspond with the predetermined range, then a user may be alerted that the measured viscosity does not correspond with the predetermined range.

A fuel tank containing a fuel and oil mixture is managed to determine if the fuel and oil mixture contains the correct ratio for a motor. The fuel tank containing a fuel and oil mixture is monitored. A fuel to oil ratio is selected for the motor. A combined viscosity of the fuel and oil mixture is calculated with respect to the fuel to oil ratio, and the temperature of the fuel and oil mixture. The combined viscosity is used to determine a predetermined range of the combined viscosity. The viscosity of the fuel and oil mixture within the fuel tank is measured as a measured viscosity. If the measured viscosity of the fuel and oil mixture does not correspond with the predetermined range, then a user may be alerted that the measured viscosity does not correspond with the predetermined range.

A fuel tank containing a fuel and oil mixture is managed to determine if the fuel and oil mixture contains the correct ratio for a motor. The fuel tank containing a fuel and oil mixture is monitored. A fuel to oil ratio is selected for the motor. A combined viscosity of the fuel and oil mixture is calculated with respect to the fuel to oil ratio, and the temperature of the fuel and oil mixture. The combined viscosity is used to determine a predetermined range of the combined viscosity. The viscosity of the fuel and oil mixture within the fuel tank is measured as a measured viscosity. If the measured viscosity of the fuel and oil mixture does not correspond with the predetermined range, then a user may be alerted that the measured viscosity does not correspond with the predetermined range.

A portable generator includes an engine including an air-fuel mixing device, an alternator, first and second fuel reservoir fluidly coupled to the air-fuel mixing device, a first fuel valve and a second fuel valve movable to an open position that allows fuel to flow from respective fuel reservoirs to the air-fuel mixing device and a closed position that prevents fuel from flowing from respective fuel reservoirs to the air-fuel mixing device, a fuel selector input device operable to select the first or second fuel reservoir as the source of fuel, and a controller programmed to automatically open or close the first fuel valve and open or close the second fuel valve in response to an input from the fuel selector input device indicating selection of the first or second fuel reservoirs.

A technique for fuel system protection for an internal combustion engine includes introducing a directly injected fuel into a combustion chamber through a direct fuel injector, introducing a fumigated fuel upstream of an intake valve, selectively operating the internal combustion engine with at least one of the directly injected fuel and the fumigated fuel, determining a temperature of the direct fuel injector as a first function of engine operating parameters, and performing a temperature mitigation technique when the temperature rises above a first predetermined value such that the temperature is maintained below a second predetermined value.