A method is provided for operating an internal combustion piston engine, including introducing air into a cylinder of the engine, compressing the air in a first compression stroke of the cylinder, providing fuel into the cylinder for a first combustion, with a portion of the oxygen in the compressed air as oxidant, in a first power stroke succeeding the first compression stroke, to produce residues including oxygen, compressing the residues in a second compression stroke succeeding the first power stroke, and providing, after the first combustion, fuel into the cylinder for a second combustion, with at least a portion of the oxygen of the residues as oxidant, in a second power stroke succeeding the second compression stroke, wherein the first compression stroke is repealed immediately after the second power stroke, and the introduction of air into the cylinder is done at the end of the second power stroke and/or at the beginning of the first compression stroke.

Systems and methods for controlling fuel factions delivered to different cylinders are provided. In one example, a controller is configured to, during a single engine cycle and responsive to a first condition, deliver a lower fraction of a first fuel into a donor cylinder in comparison to a fraction of the first fuel being injected into a non-donor cylinder and deliver a higher fraction of a second fuel into the donor cylinder in comparison to a fraction of the second fuel being injected into the non-donor cylinder.

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.

An engine system includes an engine having a combustion chamber, an intake gas passage through which air to be supplied to the combustion chamber flows, an exhaust gas passage through which exhaust gas generated from the combustion chamber flows, a reformer configured to reform the fuel to generate a reformed gas containing hydrogen, a gas supply passage through which air to be supplied to the reformer flows, a bypass passage connected to the gas supply passage and the exhaust gas passage so as to bypass the reformer and through which the fuel having passed through the reformer is circulated to an upstream of the reformer, and a switching valve switched between a normal position that does not allow the fuel having passed through the reformer to flow to the bypass passage and a circulating position that allows the fuel having passed through the reformer to flow to the bypass passage.

A system, apparatus, and method for controlling an engine system can provide fuel reactivity compensation control for an engine of the engine system. Pilot fuel quantity supplied to the engine can be controlled using a nitrous oxide (NOx) error. Likewise, air-to-fuel ratio (AFR) for the engine can be controlled using the NOx error. Each of a pilot fuel offset and an AFR control trim can be generated using the NOx error. The pilot fuel offset and the AFR control trim can be used to control the pilot fuel quantity and the AFR, respectively.

A system, apparatus, and method for controlling an engine system can provide fuel reactivity compensation control for an engine of the engine system. The control can include controlling pilot fuel quantity supplied to an engine based on a pilot fuel offset value; and controlling air-to-fuel ratio (AFR) for the engine based on an AFR control trim value. A NOx error value can be used to generate one of the pilot fuel offset value or the AFR control trim value, and an exhaust temperature error value can be used to generate the other of the pilot fuel offset value or the AFR control trim value.

Various methods and systems are provided for using only hydrogen as fuel in a duel fuel engine. In one example, a method may include direct injecting only hydrogen as fuel to one or more engine cylinders and compression igniting the injected hydrogen.

Various methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system comprises a first fuel system to deliver liquid fuel to at least one cylinder of an engine, a second fuel system to deliver gaseous fuel to the at least one cylinder, and a controller. The controller is configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder thereby to ignite the liquid fuel and the gaseous fuel in the at least one cylinder via compression-ignition, and adjust an amount of the gaseous fuel relative to an amount 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.

Methods of operation of liquid and gaseous multi-fuel compression ignition engines that may be operated on a gaseous fuel or a liquid fuel, or a combination of both a gaseous fuel and a liquid fuel at the same time and in some embodiments, in the same combustion event. Various embodiments are disclosed.

A method of operating an internal combustion engine having at least one combustion chamber and an actuator disposed therein being arranged to drive an output shaft of the engine, the method comprising: 5 (i) injecting a water containing fuel into the combustion chamber; (ii) flash boiling the water-containing fuel to form water vapour within the combustion chamber; (iii) thermolyzing the water vapour to form hydrogen gas and oxygen gas; and (iv) combusting the hydrogen gas to drive the actuator within the combustion chamber to 10 thereby drive the connected output shaft of the combustion engine.