A method of operating a dual fuel engine includes conveying intake air, and a first fuel as a vapor and as a liquid, into a combustion cylinder in an engine, and directly injecting a second fuel into the combustion cylinder to form a first combustion charge of the first fuel as a vapor and as a liquid, the second fuel, and intake air. The second fuel is ignited to initiate combustion of the first combustion charge. Operating the dual fuel engine further includes varying at least one of, a vapor proportion of the first fuel or a total proportion of the first fuel, in a subsequent combustion charge to mitigate undesired combustion. The first fuel can include a liquid alcohol fuel. The second fuel can include a liquid compression-ignition fuel. Related apparatus and control logic is also disclosed.

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.

Various methods and systems are provided for controlling emissions and a likelihood of engine knock during combustion in a multi-fuel engine. A method for an engine includes mixing an amount of a first fuel and an amount of a second fuel to combust a fuel mixture having a fuel ratio of the first fuel relative to the second fuel, the first fuel having a faster combustion flame speed relative to the second fuel, the fuel mixture having an air-to-fuel ratio with an amount of air delivered to the engine. The method further includes controlling either or both of a speed of combustion and a stability of combustion of the fuel mixture with the amount of air delivered to the engine by changing at least one of the fuel ratio, the air-to-fuel ratio, or both of the fuel ratio and the air-to-fuel ratio.

An engine operable in a premixed combustion system and a diffusion combustion system. The engine includes a main fuel injection valve, a pilot fuel injection valve, a liquid fuel tank, a main fuel supply path, a pilot fuel supply path, a pilot fuel filter, a pilot fuel high-pressure pump, a pilot fuel tank, and a pilot fuel supply pump. The pilot fuel tank stores pilot fuel sent from the pilot fuel high-pressure pump and not injected by the pilot fuel injection valve. This pilot fuel is sent to an automatic backwash filter and a pilot fuel filter while not passing through the liquid fuel tank.

Systems and methods for automatic calibration of large industrial engines in applications where the quality of the fuel supply is unknown and/or variable over time, particularly engines that drive compressors on a natural gas well site. A combination of throttles and an oxygen sensor including a mass-flow-air throttle and a mass-flow-gas throttle to determine the mass flow of air and mass flow of gas. As a response to exhaust gas oxygen level readings, the mass flow measurements are used to determine real time air-fuel ratios. An algorithm uses the air-fuel ratios as input data, wherein a microcontroller adjusts the throttles to meet engine performance demands. Additionally, using the air-fuel ratio data and suggested engine OEM calibration specifications as block multiplier inputs, particular fuel properties, such as British Thermal Unit (BTU) content, can be accurately interpolated, thereby enabling automatic calibration of the engine .

An engine including a main fuel injection valve, a pilot fuel injection valve, a liquid fuel supply rail pipe, and a pilot fuel supply rail pipe. The main fuel injection valve supplies liquid fuel from the liquid fuel supply rail pipe to a combustion chamber during combustion in a diffusion combustion system. The pilot fuel injection valve supplies pilot fuel from the pilot fuel supply rail pipe to the combustion chamber in order to ignite gaseous fuel during combustion in a premixed combustion system. The liquid fuel supply rail pipe is disposed at one side of an imaginary vertical plane including an axis of a crank shaft. The pilot fuel supply rail pipe is disposed at the side of the imaginary vertical plane at which the liquid fuel supply rail pipe is disposed.

A gas fuel supply system for supplying the gas fuel via an opening of an intake supply pipe that is connected to a combustion chamber in an engine operable in each of a gas fuel combustion mode and an oil fuel combustion mode includes: the gas fuel supply valve for regulating an amount of the gas fuel, the gas fuel supply valve having plural gas supply holes, from which the gas fuel is fed in a direction toward the opening when the valve is opened; and an opening regulation valve provided between the gas fuel supply valve and the opening and having an opening hole, an opening area of which can be regulated. The gas fuel supply system is configured that extended axes of all the gas supply holes pass through the fully opened opening hole.

A multi-fuel switching device, including a gas part, is provided. The gas part includes a switching valve. The switching valve includes a housing having an air inlet and an air outlet. An internal rotation of the housing is provided with a valve core located between the air inlet and the air outlet. The valve core is provided with a first airway and a second airway. Cross-sectional sizes of the first airway and the second airway are different. The first airway or the second airway is selected through rotating the valve core to connect the air inlet and the air outlet. The solution solves the issue that a fuel switching device in the prior art cannot adapt to three or more fuels, which causes an internal combustion engine to be unable to maintain the optimal working state.

A method for controlling an internal combustion engine operating on at least partly gaseous fuel is disclosed. The method may include providing a desired burn rate profile corresponding to a desired operation of the internal combustion engine. The method may further include selecting first operating parameters such that an operation of the internal combustion engine with a first gas composition produces a first burn rate profile that corresponds to the desired burn rate profile. The method may also include operating the internal combustion engine with the first operating parameters using a second gas composition. The method may include determining that the second burn rate profile differs from the desired burn rate profile. In addition, the method may include adjusting an operating parameter from among the first operating parameters of the internal combustion engine to approach the desired burn rate profile.

The invented system adds some petrol fuel to the vehicle engine which runs with natural gas (CNG or LPG). It causes a simultaneous combustion of petrol and natural gas (CNG or LPG). This action decreases depreciation of engine, increases power of the engine and reduces fuel consumption in natural gas vehicles. The above-mentioned system consists of an innovative petrol holder storage, an electronically circuit, a relay, a lever micro switch and a petrol fuel injector. Whenever the accelerator pedal is pressed more than a certain amount, the system will be activated and command to inject petrol collected in the storage into the air manifold.