A liquid fuel injector such as for a dual fuel system in an internal combustion engine includes two-way injection control valves for controlling twin outlet checks. A first set of orifices are arranged in an A-F-Z pattern, and a second set of orifices are arranged in an A-F-Z pattern, within the fuel injector, among a high-pressure inlet passage, a low-pressure space, and first and second outlet check control chambers, respectively. A common nozzle supply cavity is fluidly connected to the high-pressure inlet passage and supplies each of two sets of nozzle outlets opened and closed by the twin outlet checks.

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 first engine fuel, for example diesel fuel, is reformed (preferably via steam reforming) to produce syngas for use as a second engine fuel, with the fuels then both being used in an internal combustion engine to perform Reactivity Controlled Compression Ignition (RCCI). The syngas is produced and supplied to the engine as a supercritical fluid, thereby avoiding the pumping losses that would occur if syngas was pressurized for supply/injection. The reforming is done by a reformer which is provided as a unit with the engine (e.g., both the engine and reformer are onboard a vehicle), thereby effectively allowing use of a single fuel for RCCI engine operation.

A liquid fuel injector such as for a dual fuel system in an internal combustion engine includes two-way injection control valves for controlling twin outlet checks. A first set of orifices are arranged in an A-F-Z pattern, and a second set of orifices are arranged in an A-F-Z pattern, within the fuel injector, among a high-pressure inlet passage, a low-pressure space, and first and second outlet check control chambers, respectively. A common nozzle supply cavity is fluidly connected to the high-pressure inlet passage and supplies each of two sets of nozzle outlets opened and closed by the twin outlet checks.

A first engine fuel, for example diesel fuel, is reformed (preferably via steam reforming) to produce syngas for use as a second engine fuel, with the fuels then both being used in an internal combustion engine to perform Reactivity Controlled Compression Ignition (RCCI). The syngas is produced and supplied to the engine as a supercritical fluid, thereby avoiding the pumping losses that would occur if syngas was pressurized for supply/injection. The reforming is done by a reformer which is provided as a unit with the engine (e.g., both the engine and reformer are onboard a vehicle), thereby effectively allowing use of a single fuel for RCCI engine operation.

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.

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 system, method and apparatus for controlling a gas substitution characteristic in a dual fuel engine are provided. The gas substitution characteristic can be controlled based on measured characteristics directly or indirectly associated with operation of the dual fuel engine, including intake manifold air pressure (IMAP), load of the dual fuel engine, ambient air temperature, exhaust temperature, fan speed, and/or pressure of natural gas supplied to the dual fuel engine. Further, the gas substitution characteristic can be controlled by controlling intake manifold air temperature (IMAT) based on control of a cooling capacity of a cooling circuit.

An engine having at least a primary and secondary fuel supplies is configured to operate by determining a fueling mode for each of first and second groupings of cylinders, independently. A method, therefore, for operating the engine includes monitoring engine operating parameters with an electronic controller, determining an engine operating point based on the engine operating parameters, calculating a first operating mode of a first cylinder grouping based on the engine operating point, calculating a second operating mode of a second cylinder grouping based on the engine operating point, and selectively activating at least one of a diesel injector, a gaseous fuel injector and a spark device in each engine cylinder separately and selectively for each cylinder of the first and second cylinder grouping based on the engine operating point.

An engine having at least a primary and secondary fuel supplies is configured to operate by determining a fueling mode for each of first and second groupings of cylinders, independently. A method, therefore, for operating the engine includes monitoring engine operating parameters with an electronic controller, determining an engine operating point based on the engine operating parameters, calculating a first operating mode of a first cylinder grouping based on the engine operating point, calculating a second operating mode of a second cylinder grouping based on the engine operating point, and selectively activating at least one of a diesel injector, a gaseous fuel injector and a spark device in each engine cylinder separately and selectively for each cylinder of the first and second cylinder grouping based on the engine operating point.