Abstract: Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection 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. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

Abstract: Embodiments of methods and systems related to operating a mobile asset are provided. In one example, a method for operating a mobile asset includes adjusting a fuel combustion ratio of a plurality of mobile assets based on an emission type exceeding a corresponding threshold, wherein the fuel combustion ratio includes a plurality of fuel types.

Abstract: An engine control unit of a multi-fuel is provided. The engine consumes a mixture of a first combustion fuel and a second combustion fuel. The engine control unit includes hardware circuitry that includes one or more processors configured to calculate an autoignition delay of the mixture of the air and the second combustion fuel based on current operating conditions of the multi-fuel engine. The one or more processors also are configured to calculate an upper limit on an amount of the second combustion fuel that is supplied to the multi-fuel engine based on the autoignition delay that is calculated.

Abstract: A method provides for operating an engine configured to use a plurality of differing fuels. The method includes determining a fuel combustion ratio of the plurality of differing fuels associated with at least one engine cylinder of the engine based at least in part on one or more of a plurality of characteristic profiles. This maintains one or more of a plurality of actual values associated with usage of the plurality of differing fuels relative to defined corresponding threshold values. The fuel combustion ratio includes a ratio of the plurality of differing fuels to be delivered to the at least one engine cylinder. A fuel delivery system delivers the plurality of differing fuels to the at least one engine cylinder based on the fuel combustion ratio.

Abstract: Embodiments of methods and systems related to operating a mobile asset are provided. In one example, a method for operating a mobile asset includes supplying an engine with a fuel controller a first amount of a first fuel and a second amount of a second fuel and combusting the first fuel and the second fuel at a fuel combustion ratio in at least one cylinder of the engine, the first amount and the second amount being selected based on route information for a route along which the mobile asset is operable to travel and a projected exhaustion of the first fuel that does not precede a projected exhaustion of the second fuel, wherein the mobile asset is unable to operate with the second fuel alone.

Abstract: A method provides for operating an engine configured to use a plurality of differing fuels. The method includes determining a fuel combustion ratio of the plurality of differing fuels associated with at least one engine cylinder of the engine based at least in part on one or more of a plurality of characteristic profiles. This maintains one or more of a plurality of actual values associated with usage of the plurality of differing fuels relative to defined corresponding threshold values. The fuel combustion ratio includes a ratio of the plurality of differing fuels to be delivered to the at least one engine cylinder. A fuel delivery system delivers the plurality of differing fuels to the at least one engine cylinder based on the fuel combustion ratio.

Abstract: A method provides for operating an engine configured to use a plurality of differing fuels. The method includes determining a fuel combustion ratio of the plurality of differing fuels associated with at least one engine cylinder of the engine based at least in part on one or more of a plurality of characteristic profiles. This maintains one or more of a plurality of actual values associated with usage of the plurality of differing fuels relative to defined corresponding threshold values. The fuel combustion ratio includes a ratio of the plurality of differing fuels to be delivered to the at least one engine cylinder. A fuel delivery system delivers the plurality of differing fuels to the at least one engine cylinder based on the fuel combustion ratio.

Abstract: Embodiments of methods and systems related to operating a mobile asset are provided. In one example, a method for operating a mobile asset includes adjusting a fuel combustion ratio of a plurality of mobile assets based on an emission type exceeding a corresponding threshold, wherein the fuel combustion ratio includes a plurality of fuel types.

Abstract: Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection 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. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

Abstract: An engine control unit of a multi-fuel is provided. The engine consumes a mixture of a first combustion fuel and a second combustion fuel. The engine control unit includes hardware circuitry that includes one or more processors configured to calculate an autoignition delay of the mixture of the air and the second combustion fuel based on current operating conditions of the multi-fuel engine. The one or more processors also are configured to calculate an upper limit on an amount of the second combustion fuel that is supplied to the multi-fuel engine based on the autoignition delay that is calculated.

Abstract: Methods for preparing ceramic matrix composites using melt infiltration and chemical vapor infiltration are provided as well as the resulting ceramic matrix composites. The methods and products include the incorporation of sacrificial fibers to provide improved infiltration of the fluid infiltrant. The sacrificial fibers are removed, such as decomposed during pyrolysis, resulting in the formation of regular and elongate channels throughout the ceramic matrix composite. Infiltration of the fluid infiltrant can then take place using the elongate channels resulting in improved density and an improved ceramic matrix composite product.

Abstract: A method provides for operating an engine configured to use a plurality of differing fuels. The method includes determining a fuel combustion ratio of the plurality of differing fuels associated with at least one engine cylinder of the engine based at least in part on one or more of a plurality of characteristic profiles. This maintains one or more of a plurality of actual values associated with usage of the plurality of differing fuels relative to defined corresponding threshold values. The fuel combustion ratio includes a ratio of the plurality of differing fuels to be delivered to the at least one engine cylinder. A fuel delivery system delivers the plurality of differing fuels to the at least one engine cylinder based on the fuel combustion ratio.

Abstract: Methods for preparing ceramic matrix composites using melt infiltration and chemical vapor infiltration are provided as well as the resulting ceramic matrix composites. The methods and products include the incorporation of sacrificial fibers to provide improved infiltration of the fluid infiltrant. The sacrificial fibers are removed, such as decomposed during pyrolysis, resulting in the formation of regular and elongate channels throughout the ceramic matrix composite. Infiltration of the fluid infiltrant can then take place using the elongate channels resulting in improved density and an improved ceramic matrix composite product.

Abstract: Embodiments of methods and systems related to operating a mobile asset are provided. In one example, a method for operating a mobile asset includes supplying an engine with a fuel controller a first amount of a first fuel and a second amount of a second fuel and combusting the first fuel and the second fuel at a fuel combustion ratio in at least one cylinder of the engine, the first amount and the second amount being selected based on route information for a route along which the mobile asset is operable to travel and a projected exhaustion of the first fuel that does not precede a projected exhaustion of the second fuel, wherein the mobile asset is unable to operate with the second fuel alone.

Abstract: Methods for preparing ceramic matrix composites using melt infiltration and chemical vapor infiltration are provided as well as the resulting ceramic matrix composites. The methods and products include the incorporation of sacrificial fibers to provide improved infiltration of the fluid infiltrant. The sacrificial fibers are removed, such as decomposed during pyrolysis, resulting in the formation of regular and elongate channels throughout the ceramic matrix composite. Infiltration of the fluid infiltrant can then take place using the elongate channels resulting in improved density and an improved ceramic matrix composite product.

Abstract: Embodiments of methods and systems related to operating a mobile asset are provided. In one example, a method for operating a mobile asset includes supplying an engine with a fuel controller a first amount of a first fuel and a second amount of a second fuel and combusting the first fuel and the second fuel at a fuel combustion ratio in at least one cylinder of the engine, the first amount and the second amount being selected based on route information for a route along which the mobile asset is operable to travel and a projected exhaustion of the first fuel that does not precede a projected exhaustion of the second fuel, wherein the mobile asset is unable to operate with the second fuel alone.

Abstract: A system includes one or more processors configured to be operably coupled to a vehicle system configured to travel along a route during a trip. The vehicle system has a vehicle particulate filter (VPF) disposed within an exhaust passage of the vehicle system. The one or more processors are configured to determine, based on trip information about the trip of the vehicle system, one or more regeneration-incompatible (RI) portions of the trip. The RI portions are associated with operating conditions of the vehicle system that are unsuitable for contemporaneous active regeneration of the VPF. The one or more processors are further configured to schedule an active regeneration (AR) event for the vehicle system based on the one or more RI portions of the trip. The AR event occurs during a regeneration portion of the trip.

Abstract: Methods for preparing ceramic matrix composites using melt infiltration and chemical vapor infiltration are provided as well as the resulting ceramic matrix composites. The methods and products include the incorporation of sacrificial fibers to provide improved infiltration of the fluid infiltrant. The sacrificial fibers are removed, such as decomposed during pyrolysis, resulting in the formation of regular and elongate channels throughout the ceramic matrix composite. Infiltration of the fluid infiltrant can then take place using the elongate channels resulting in improved density and an improved ceramic matrix composite product.

Abstract: A system includes one or more processors configured to be operably coupled to a vehicle system configured to travel along a route during a trip. The vehicle system has a vehicle particulate filter (VPF) disposed within an exhaust passage of the vehicle system. The one or more processors are configured to determine, based on trip information about the trip of the vehicle system, one or more regeneration-incompatible (RI) portions of the trip. The RI portions are associated with operating conditions of the vehicle system that are unsuitable for contemporaneous active regeneration of the VPF. The one or more processors are further configured to schedule an active regeneration (AR) event for the vehicle system based on the one or more RI portions of the trip. The AR event occurs during a regeneration portion of the trip.

Abstract: According to various embodiments, an exhaust treatment system includes a catalyst that is in direct contact with an exhaust stream, at least one sensor that senses a system parameter and produces one or more signals corresponding to the system parameter, and a controller that is configured to receive the one or more signals and control catalyst performance based on the one or more signals by regenerating the catalyst. Regenerating the catalyst includes increasing a temperature of the exhaust stream flowing to the catalyst and directing a reductant injector to adjust a flow rate of reductant being injected into the exhaust stream flowing to the catalyst.