Systems and methods for operating an engine that includes an exhaust system with a differential pressure sensor are described. In one example, output of the differential pressure sensor is compared to output of a barometric pressure sensor to determine whether or not the barometric pressure sensor is degraded. The output of the differential pressure sensor may be monitored while the engine is rotated without being fueled.

Operating an internal combustion engine system includes combusting gaseous hydrogen fuel and gaseous hydrocarbon fuel at a first substitution ratio in a plurality of cylinders in an engine, inputting an emissions cost value and a hydrogen cost value to a fuel blending control system for the engine, and determining, by way of an electronic control unit of the fuel blending control system, a fuel blending control term based on the respective cost values. Operating the engine system further includes varying admission of at least one of the hydrogen fuel or the hydrocarbon fuel to an intake system for the engine based on the fuel blending control term, and combusting the hydrogen fuel and the hydrocarbon fuel at a second substitution ratio produced by the varied admission in the plurality of cylinders in the engine.

A control device of an exhaust sensor comprises a heater control part configured to set a target temperature of an electrochemical cell and control a heater so that a temperature of the electrochemical cell becomes the target temperature, and a judging part configured to judge whether a water repellency of a protective layer is falling when the heater control part sets the target temperature to a temperature of a lowest temperature at which a Leidenfrost phenomenon occurs at an outer surface of the protective layer or more. The heater control part is configured to rise the target temperature when the judging part judges that the water repellency of the protective layer is falling.

A filling of an exhaust gas component storage of a catalytic converter is regulated. An actual fill level of the exhaust gas component storage is ascertained using a first system model, and a base lambda setpoint value for a first control loop is predefined by a second control loop. An initial value for the base lambda setpoint value is converted into a fictitious fill level, the fictitious fill level being compared with a setpoint value for the fill level output, and the base lambda setpoint value being iteratively changed as a function of the comparison result, if a difference between the setpoint value for the fill level and the fictitious fill level is greater than a predefined degree. The base lambda setpoint value is not changed if no difference exists between the setpoint value for the fill level and the fictitious fill level.

A method for controlling an internal combustion engine system including a particulate filter includes receiving a desired output for an internal combustion engine and receiving sensor information including information indicative of a quantity of soot in the particulate filter. The method includes calculating a plurality of sets of engine performance values based on respective sets of candidate control points, each set of engine performance values including a soot change rate at which the quantity of soot changes over time and determining whether the soot change rate satisfies a soot change rate limit that requires an increase in the quantity of soot in the particulate filter. The method also includes controlling the internal combustion engine based on a set of candidate control points that satisfies the soot change rate limit.

Systems and methods for operating an internal combustion engine that includes an oxygen sensor are described. In one example, a voltage that is applied to a heating element of an oxygen sensor is integrated to determine a resistance of the heating element. The resistance of the heating element is the basis for adjusting voltage applied to the heating element during subsequent engine starts.

Systems and methods for operating an engine that includes an exhaust system with a differential pressure sensor are described. In one example, output of the differential pressure sensor is compared to output of a barometric pressure sensor to determine whether or not the barometric pressure sensor is degraded. The output of the differential pressure sensor may be monitored while the engine is rotated without being fueled.

A method for controlling an internal combustion engine system including a particulate filter includes receiving a desired output for an internal combustion engine and receiving sensor information including information indicative of a quantity of soot in the particulate filter. The method includes calculating a plurality of sets of engine performance values based on respective sets of candidate control points, each set of engine performance values including a soot change rate at which the quantity of soot changes over time and determining whether the soot change rate satisfies a soot change rate limit that requires an increase in the quantity of soot in the particulate filter. The method also includes controlling the internal combustion engine based on a set of candidate control points that satisfies the soot change rate limit.

A control device of an exhaust sensor comprises a heater control part configured to set a target temperature of an electrochemical cell and control a heater so that a temperature of the electrochemical cell becomes the target temperature, and a judging part configured to judge whether a water repellency of a protective layer is falling when the heater control part sets the target temperature to a temperature of a lowest temperature at which a Leidenfrost phenomenon occurs at an outer surface of the protective layer or more. The heater control part is configured to rise the target temperature when the judging part judges that the water repellency of the protective layer is falling.

Systems and methods for operating an internal combustion engine that includes an oxygen sensor are described. In one example, a voltage that is applied to a heating element of an oxygen sensor is integrated to determine a resistance of the heating element. The resistance of the heating element is the basis for adjusting voltage applied to the heating element during subsequent engine starts.