Abstract: A resonant sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid and to generate an electric field between the free-standing electrodes. A controller measures an impedance response of the sensor to the fluid between the electrodes to determine an aging effect of the sensor.

Abstract: A multi-fuel injector assembly in one embodiment includes a first fuel injector assembly to deliver a first type of fuel and a second fuel delivery system to deliver a second type of fuel. The first fuel injector includes a first nozzle, at least one first needle, and at least one first actuator configured to move the at least one first needle. The at least one first actuator moves the at least one first needle to a first fuel delivery configuration that corresponds to a first fuel mixture composition, and a second fuel delivery configuration that corresponds to a second fuel mixture composition.

Abstract: A mixing structure can include a body having first conduits, mixture conduits, and second conduits extending through the body to the internal volume. The first conduits may be closer to a first side of the body than the mixture conduits and the second conduits. The second conduits may closer to another side of the body than the first conduits and the mixture conduits. The internal volume may receive liquid streams from an injector. The first conduits and the second conduits may receive gas streams from outside the body. The body may thermally modify the gas streams and entrain the gas streams into the liquid streams in the internal volume. The mixture conduits may be positioned to direct the gas streams entrained into the liquid streams out of the body in directions directed toward the second side of the body and away from the first side of the body.

Abstract: A fuel and gas mixing structure for an engine is provided. This mixing structure includes a body configured to be positioned between a fuel injector and a cylinder of an engine. The body defines an interior volume that is configured to receive gas (e.g., air) from outside the body and to receive one or more streams of fuel from the fuel injector in the interior volume. The body also includes one or more upper channels and one or more lower channels that are configured to provide a substantially similar amount of flow relative to each other to the interior volume The body also defines one or more mixture conduits configured to conduct plumes of the fuel and gas, while mixing, from the interior volume to one or more exit ports and therethrough to the cylinder.

Abstract: A resonant sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid and to generate an electric field between the free-standing electrodes. A controller measures an impedance response of the sensor to the fluid between the electrodes to determine an aging effect of the sensor.

Abstract: A resonant sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid and to generate an electric field between the free-standing electrodes. A controller measures an impedance response of the sensor to the fluid between the electrodes to determine an aging effect of the sensor.

Abstract: A multi-fuel injector assembly in one embodiment includes a first fuel injector assembly to deliver a first type of fuel and a second fuel delivery system to deliver a second type of fuel. The first fuel injector includes a first nozzle, at least one first needle, and at least one first actuator configured to move the at least one first needle. The at least one first actuator moves the at least one first needle to a first fuel delivery configuration that corresponds to a first fuel mixture composition, and a second fuel delivery configuration that corresponds to a second fuel mixture composition.

Abstract: A resonant sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid and to generate an electric field between the free-standing electrodes. A controller measures an impedance response of the sensor to the fluid between the electrodes to determine an aging effect of the sensor.

Abstract: A fuel injector assembly in one embodiment includes a nozzle, at least one needle, and at least one actuator. The nozzle includes at least one cavity in fluid communication with nozzle openings. The at least one needle is movably disposed within the at least one cavity, and prevents flow through the nozzle openings in a closed position. The at least one actuator is configured to move the at least one needle within the cavity. The at least one actuator is configured to move the at least one needle to at least a first fuel delivery configuration and a second fuel delivery configuration. A first amount of fuel is delivered through the nozzle openings with the at least one needle in the first fuel delivery configuration, and a second amount of fuel is delivered through the nozzle openings with the at least one needle in the second fuel delivery configuration.

Abstract: A fuel and gas mixing structure for an engine is provided. This mixing structure includes a body configured to be positioned between a fuel injector and a cylinder of an engine. The body defines an interior volume that is configured to receive gas from outside the body and to receive one or more streams of fuel from the fuel injector in the interior volume. The body also defines one or more mixture conduits configured to conduct plumes of the fuel and gas, while mixing, from the interior volume to one or more exit ports and therethrough to the cylinder.

Abstract: A locomotive system is provided that includes a platform, plural wheel-axle sets operably coupled to the platform, a reservoir attached to the platform and configured to hold a fluid, and a resonant sensor probe assembly coupled to the reservoir. The sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid, to generate an electric field between the free-standing electrodes, and to measure an impedance response of the sensor to the fluid between the electrodes.

Abstract: A fuel and gas mixing structure for an engine is provided. This mixing structure includes a body configured to be positioned between a fuel injector and a cylinder of an engine. The body defines an interior volume that is configured to receive gas (e.g., air) from outside the body and to receive one or more streams of fuel from the fuel injector in the interior volume. The body also includes one or more upper channels and one or more lower channels that are configured to provide a substantially similar amount of flow relative to each other to the interior volume The body also defines one or more mixture conduits configured to conduct plumes of the fuel and gas, while mixing, from the interior volume to one or more exit ports and therethrough to the cylinder.

Abstract: A method involves receiving a plurality of engine parameters and a sensed ambient operating condition during operation of an engine and determining a current substitution rate based on the plurality of engine parameter. The method also involves determining at least one of a pre-combustion temperature and an end gas temperature based on the plurality of engine parameters and the sensed ambient operating condition and determining a maximum substitution rate based on at least one of the pre-combustion temperature and the end gas temperature. The method further involves comparing the current substitution rate with the maximum substitution rate and controlling at least one engine parameter among the plurality of engine parameters if the current substitution rate is different from the maximum substitution rate so as to generate the current substitution rate to less than or equal to the maximum substitution rate.

Abstract: A fuel injector assembly in one embodiment includes a nozzle, at least one needle, and at least one actuator. The nozzle includes at least one cavity in fluid communication with nozzle openings. The at least one needle is movably disposed within the at least one cavity, and prevents flow through the nozzle openings in a closed position. The at least one actuator is configured to move the at least one needle within the cavity. The at least one actuator is configured to move the at least one needle to at least a first fuel delivery configuration and a second fuel delivery configuration. A first amount of fuel is delivered through the nozzle openings with the at least one needle in the first fuel delivery configuration, and a second amount of fuel is delivered through the nozzle openings with the at least one needle in the second fuel delivery configuration.

Abstract: A fuel and gas mixing structure for an engine is provided. This mixing structure includes a body configured to be positioned between a fuel injector and a cylinder of an engine. The body defines an interior volume that is configured to receive gas from outside the body and to receive one or more streams of fuel from the fuel injector in the interior volume. The body also defines one or more mixture conduits configured to conduct plumes of the fuel and gas, while mixing, from the interior volume to one or more exit ports and therethrough to the cylinder.

Abstract: A locomotive system is provided that includes a platform, plural wheel-axle sets operably coupled to the platform, a reservoir attached to the platform and configured to hold a fluid, and a resonant sensor probe assembly coupled to the reservoir. The sensor probe assembly includes a substrate formed from one or more dielectric materials and free-standing electrodes coupled with the substrate. The free-standing electrodes are configured to be placed into the fluid, to generate an electric field between the free-standing electrodes, and to measure an impedance response of the sensor to the fluid between the electrodes.

Abstract: A fuel injector assembly in one embodiment includes a nozzle, at least one needle, and at least one actuator. The nozzle includes at least one cavity in fluid communication with nozzle openings. The at least one needle is movably disposed within the at least one cavity, and prevents flow through the nozzle openings in a closed position. The at least one actuator is configured to move the at least one needle within the cavity. The at least one actuator is configured to move the at least one needle to at least a first fuel delivery configuration and a second fuel delivery configuration. A first amount of fuel is delivered through the nozzle openings with the at least one needle in the first fuel delivery configuration, and a second amount of fuel is delivered through the nozzle openings with the at least one needle in the second fuel delivery configuration.

Abstract: Dual-fuel engine system includes cylinders in which the cylinders have an intake valve and an exhaust valve that control a flow of fluid into and out of a combustion chamber of the corresponding cylinder. The intake valve is configured to have an intake valve closure (IVC) timing. The dual-fuel engine system is configured to operate in a single-fuel mode and a dual-fuel mode. The combustion chamber and a piston are designed to provide a compression ratio. The dual-fuel engine system also includes one or more processors that are operably coupled to and configured to control operation of the first fuel injector. The compression ratio and the IVC timing are selected to achieve a target pre-combustion temperature. The target pre-combustion temperature permits the dual-fuel engine system to operate at a high substitution rate in the dual-fuel mode and at a sufficient fuel efficiency in the single-fuel mode.

Abstract: A fuel injector assembly in one embodiment includes a nozzle, at least one needle, and at least one actuator. The nozzle includes at least one cavity in fluid communication with nozzle openings. The at least one needle is movably disposed within the at least one cavity, and prevents flow through the nozzle openings in a closed position. The at least one actuator is configured to move the at least one needle within the cavity. The at least one actuator is configured to move the at least one needle to at least a first fuel delivery configuration and a second fuel delivery configuration. A first amount of fuel is delivered through the nozzle openings with the at least one needle in the first fuel delivery configuration, and a second amount of fuel is delivered through the nozzle openings with the at least one needle in the second fuel delivery configuration.

Abstract: Various methods and systems are provided for a multi-fuel capable engine. In one example, a system comprises an engine having at least one cylinder controlled via an intake valve, a first fuel system to deliver liquid fuel and a second fuel system to deliver gaseous fuel to the at least one cylinder, a variable valve timing actuation system to adjust one or more of an opening or a closing timing of the intake valve, and a controller. The controller is configured to, during a liquid fuel only mode, adjust the variable valve timing actuation system to close the intake valve at a first timing based at least on engine load, and during a multi-fuel mode, adjust the variable valve timing actuation system to close the intake valve at a second timing.