Abstract: Managing firing fraction transitions of a variable displacement internal combustion engines by (a) avoiding transport delays in an Exhaust Gas Recirculation (EGR) feed by starting movement of an EGR valve position after a decision to transition to a new firing fraction has been made, but prior to the start of the transition and (b) adjusting the EGR valve as needed during the transition so as to maintain an EGR fraction within a predetermined range during the transition. By performing both (a) and (b), spikes of nitrous oxide (NOx) and/or hydrocarbon emissions are reduced or altogether eliminated during the transition.

Abstract: Systems and apparatuses include an aftertreatment system including a catalyst, and a controller coupled to the aftertreatment system. During a warmup period for an engine coupled to the catalyst, the controller is configured to determine a value of a catalyst heating metric indicative of an amount of emissions produced per unit of exhaust energy based on information received from the engine and the aftertreatment system, and control at least one of a turbocharger, a fuel injection system, or an Exhaust Gas Recirculation (EGR) system to reach a target value of the catalyst heating metric.

Abstract: A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

Abstract: A system includes an aftertreatment system having a catalyst, a heater, at least one sensor configured to determine an exhaust gas temperature, and a controller. The controller is structured to determine whether the exhaust gas temperature is at or below a predefined threshold temperature, provide a first command to start and control the heater in response to the exhaust gas temperature being at or below the predefined threshold temperature, modulate control of the heater as a function of the predefined threshold temperature and an actual temperature, and selectively provide a second command for a close post injection based on the exhaust gas temperature. The controller is further structured to coordinate the first and second commands using a chaining sequence, wherein the first command is provided followed by the second command only if the predefined threshold temperature is not attained by the first command.

Abstract: A system includes a controller configured to store a relationship matrix of a plurality of diagnostic estimators and a plurality of failure modes, each failure mode represents a type of failure that can occur with (i) a sensor or (ii) a vehicle component of a vehicle system, each diagnostic estimator is associated with a respective subset of the failure modes, each respective subset defines a control volume within the vehicle system that contains at least one of (i) one or more sensors or (ii) one or more vehicle components; store a healthy diagnostic vector regarding nominal operational parameters of the vehicle system; acquire diagnostic information regarding current operational parameters of the vehicle system to generate an error diagnostic vector; divide the error diagnostic vector by the healthy diagnostic vector to generate a ratio diagnostic vector; multiply the ratio diagnostic vector with the relationship matrix to generate a value for each failure mode.

Abstract: A method and an apparatus including a processing circuit structured to: receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, the first signal defining a duty cycle, receive a second signal indicative of a downstream air-fuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, adjust the duty cycle based at least in part on the second signal, and provide a fault signal in response to the duty cycle not meeting a duty cycle range for a predetermined period of time. A notification circuit is structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.

Abstract: A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

Abstract: A method for operating an engine fueling system to manage fuel in an accumulator supplying fuel to an engine including multiple cylinders comprising monitoring fuel load in the accumulator, determining that the engine is operating in a cylinder deactivation mode such as a skip-fire mode during which one or more fueling events to one or more of the cylinders is being skipped, and controlling a supply of fuel from a fuel pump to the accumulator during the cylinder deactivation mode operation. In embodiments, controlling the supply of fuel includes causing fuel to be supplied from the fuel pump to the accumulator if the monitored fuel load is less than or equal to a first fuel load, and causing fuel to be not supplied from the fuel pump to the accumulator if the monitored fuel load is greater than the first load value. Controlling the supply of fuel may comprise controlling the supply of fuel during each fueling event cycle of each deactivated cylinder.

Abstract: A variety of methods and arrangements are described for managing recharging of cylinders of an internal combustion engine during skip fire operation of the engine. In one method, a maximum allowed deactivation time for a cylinder is determined and the cylinder is recharged before the maximum allowed deactivation time is exceeded.

Abstract: An apparatus includes a processing circuit structured to receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, receive a second signal indicative of a downstream air-fuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, determine an actual oxygen storage capacity of the catalyst based at least in part on the received first signal and the received second signal, compare the actual oxygen storage capacity to a maximum storage capacity, and provide a fault signal in response to the actual oxygen storage capacity exceeding the maximum storage capacity. The apparatus also includes a notification circuit structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.

Abstract: Managing firing fraction transitions of a variable displacement internal combustion engines by (a) avoiding transport delays in an Exhaust Gas Recirculation (EGR) feed by starting movement of an EGR valve position after a decision to transition to a new firing fraction has been made, but prior to the start of the transition and (b) adjusting the EGR valve as needed during the transition so as to maintain an EGR fraction within a predetermined range during the transition. By performing both (a) and (b), spikes of nitrous oxide (NOx) and/or hydrocarbon emissions are reduced or altogether eliminated during the transition.

Abstract: A system includes an aftertreatment system having a catalyst, a heater, at least one sensor configured to determine an exhaust gas temperature, and a controller. The controller is structured to determine whether the exhaust gas temperature is at or below a predefined threshold temperature, provide a first command to start and control the heater in response to the exhaust gas temperature being at or below the predefined threshold temperature, modulate control of the heater as a function of the predefined threshold temperature and an actual temperature, and selectively provide a second command for a close post injection based on the exhaust gas temperature. The controller is further structured to coordinate the first and second commands using a chaining sequence, wherein the first command is provided followed by the second command only if the predefined threshold temperature is not attained by the first command.

Abstract: Systems and apparatuses include an aftertreatment system including a catalyst, and a controller coupled to the aftertreatment system. During a warmup period for an engine coupled to the catalyst, the controller is configured to determine a value of a catalyst heating metric indicative of an amount of emissions produced per unit of exhaust energy based on information received from the engine and the aftertreatment system, and control at least one of a turbocharger, a fuel injection system, or an Exhaust Gas Recirculation (EGR) system to reach a target value of the catalyst heating metric.

Abstract: A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a charge of a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The charge is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

Abstract: A system for detecting and controlling air-fuel ratio imbalance conditions between cylinders of an internal combustion engine having a plurality of cylinders is disclosed.

Abstract: A system for detecting and controlling air-fuel ratio imbalance conditions between cylinders of an internal combustion engine having a plurality of cylinders is disclosed.

Abstract: A system for detecting and controlling misfire and/or AFR imbalance conditions in cylinders of an internal combustion engine having a plurality of cylinders is disclosed.

Abstract: One embodiment is a method comprising operating an internal combustion engine system including multiple cylinders structured to combust a charge mixture and to output exhaust to an exhaust manifold, an electronic control system structured to control operation of the engine system and an exhaust manifold pressure (EMP) sensor structured to provide data to the electronic control system and performing an air-fuel ratio (AFR) imbalance diagnostic with the electronic control system. The AFR imbalance diagnostic may comprise the acts of processing the data to provide at least one output metric sample, determining an output metric statistic based on the at least one output metric sample, evaluating the output metric statistic relative to one or more predetermined criteria to identify an AFR imbalance condition, and providing an operator perceptible indication of the AFR imbalance condition.

Abstract: An apparatus includes a processing circuit structured to receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, receive a second signal indicative of a downstream airfuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, determine an actual oxygen storage capacity of the catalyst based at least in part on the received first signal and the received second signal, compare the actual oxygen storage capacity to a maximum storage capacity, and provide a fault signal in response to the actual oxygen storage capacity exceeding the maximum storage capacity. The apparatus also includes a notification circuit structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.

Abstract: A system for detecting and controlling air-fuel ratio imbalance conditions between cylinders of an internal combustion engine having a plurality of cylinders is disclosed.