Methods and systems are provided for injecting gaseous fuel during an engine start. In one example, a method comprises generating gaseous fuel via a fuel gasification device and injecting the gaseous fuel via a fuel injector. The fuel injector is configured to inject adjacent to an ignition device.

Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.

An internal combustion engine comprising: a main combustion chamber comprising at least one intake valve and at least one exhaust valve, wherein at least one intake port fluidically connected to an intake manifold is configured to supply an air and/or an air-fuel-mixture to the main combustion chamber via the at least one intake valve, and a pre-chamber which is in fluid connection with the main combustion chamber, wherein the pre-chamber is in fluid connection with the intake port and/or the intake manifold through a supply line, wherein at least one fuel injector is configured to enrich the air and/or air-fuel-mixture supplied to the main combustion chamber to have a lower ignition delay than an air-fuel-mixture supplied to the pre-chamber and/or air or air-fuel-mixture can be supplied to the pre-chamber to have a higher ignition delay than an air-fuel-mixture supplied to the main combustion chamber.

A pump has a plurality of pumping elements, each being independently responsive to an actuation signal from a controller. The controller is programmed to maintain a desired pressure at the pump discharge, monitor the fluid pressure at the pump discharge, compare the fluid pressure with the desired fluid pressure to determine a pressure error, provide commands to sequentially actuate the pumping elements when the pressure error is within a threshold range, and provide commands to actuate more than one of the plurality of pumping elements simultaneously, such that more than one pumped amounts of fluid are delivered simultaneously at the pump discharge, when the pressure error droops outside of the threshold range.

An interface circuit assembly for use with an electronic control unit and oxygen sensor of an internal combustion engine. The assembly includes an input port coupled to receive a signal from the oxygen sensor and a processing unit coupled with the input port. The processing unit increases the signal to an output voltage as a function of hydrogen being provided to the internal combustion engine. An output port is coupled with the processing unit and provides the output voltage to the electronic control unit.

Aspects relate to zero-emission propulsion systems and generators using ammonia (NH.sub.3) as fuel for engines and power plants. While ammonia has poor flammability, mixing hydrogen with ammonia (NH.sub.3) may improve flammability and thus facilitate the ignition of an air/ammonia mixture in engines or power plants. Alternatively, hydrogen (H.sub.2) may be supplied in a separate fuel system as a pilot fuel for pilot ignition of an air/ammonia mixture. Hydrogen can also be used in air independent systems along with oxygen (O.sub.2) from an oxygen tank. In addition to hydrogen, other bio or fossil fuels can be used as pilot fuel for pilot ignition of an air/ammonia mixture. An advantage of using existing bio or fossil fuels for pilot ignition is that engines or power plants will have a pilot fuel system with sufficient capacity to maintain normal operations if ammonia is not available.

A method for operating an internal combustion engine includes operating at least one cylinder pre-chamber in a homogeneous charge compression ignition (HCCI) combustion mode by providing an air/fuel mixture in the pre-chamber that is fluidly connected to the at least one engine cylinder, creating H and OH radicals in the pre-chamber to achieve an ignition in the at least one pre-chamber, determining whether an ignition timing is advanced or delayed relative to a desired timing, and delaying the ignition when the ignition is advanced relative to the desired timing by cooling the pre-chamber and the at least one engine cylinder.

An apparatus and method for igniting a gaseous fuel directly introduced into a combustion chamber of an internal combustion engine comprises steps of heating a space near a fuel injector nozzle; introducing a pilot amount of the gaseous fuel in the combustion chamber during a first stage injection event; controlling residency of the pilot amount in the space such that a temperature of the pilot amount increases to an auto-ignition temperature of the gaseous fuel whereby ignition occurs; introducing a main amount of the gaseous fuel during a second stage injection event after the first stage injection event; and using heat from combustion of the pilot amount to ignite the main amount.

A method for injecting gaseous fuel directly into a combustion chamber of an internal combustion engine in order to heat a catalytic converter, the method including: carrying out a main injection of gaseous fuel directly into the combustion chamber; carrying out a first post-injection following the main injection but prior to an ignition, and following the ignition and preferably following the end of combustion in the combustion chamber, carrying out a second post-injection of gaseous fuel into the combustion chamber.

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.