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: Systems and methods for diagnosing a sensor for an exhaust system may include perturbing an output signal from the sensor for the exhaust system. The method may further include monitoring an output signal from a controller for controlling a component affecting the exhaust system or an unperturbed output signal from the sensor and diagnosing the sensor based on the monitored output signal from the controller or the unperturbed output signal from the sensor. In another implementation, a first controller may output the output signal from the sensor to a second controller configured to have a predetermined response to output signal. The first controller receives a response from the second controller and diagnoses the sensor based on the received response.

Abstract: Systems and methods for diagnosing a sensor for an exhaust system may include perturbing an output signal from the sensor for the exhaust system. The method may further include monitoring an output signal from a controller for controlling a component affecting the exhaust system or an unperturbed output signal from the sensor and diagnosing the sensor based on the monitored output signal from the controller or the unperturbed output signal from the sensor. In another implementation, a first controller may output the output signal from the sensor to a second controller configured to have a predetermined response to output signal. The first controller receives a response from the second controller and diagnoses the sensor based on the received response.

Abstract: In one example, a method of operating an engine having a diesel particulate filter in a vehicle, the particulate filter having a length and depth, includes performing particulate filter regeneration in response to temperature variation across the length and/or depth of the particulate filter.

Abstract: Systems and methods for storing NH3 that has slipped through a first SCR are described. In one example, NH3 is stored in a second SCR and released to the first SCR via desorption. The systems and method may reduce NH3 consumption and increase NH3 utilization within an exhaust system.

Abstract: A particulate filter regeneration system may include an exhaust inlet, an exhaust chamber coupled downstream of the exhaust inlet, an exhaust outlet, and a flow-through wall coupled between the exhaust chamber and the exhaust outlet. The particulate filter regeneration system may further include a heater for heating the particulate filter regeneration system to enable particulate combustion and a bypass coupled to the exhaust chamber for selectively opening a filter regeneration pathway to remove accumulated particulate.

Abstract: Systems and methods for storing NH3 that has slipped through a first SCR are described. In one example, NH3 is stored in a second SCR and released to the first SCR via desorption. The systems and method may reduce NH3 consumption and increase NH3 utilization within an exhaust system.

Abstract: In one example, a method of operating an engine having a diesel particulate filter in a vehicle, the particulate filter having a length and depth, includes performing particulate filter regeneration in response to temperature variation across the length and/or depth of the particulate filter.

Abstract: A method of operating an engine having a diesel particulate filter in a vehicle is disclosed. In one example, the filter is regenerated in response to a temperature differential across each of a plurality of filter channels. The method can improve the timing of filter regeneration.

Abstract: A method of operating a diesel engine and an emission control system including a diesel particulate filter comprising of The inventors herein have realized that accurate particulate matter information for controlling processes and parameters may be realized by a method for operating an engine comprising of correlating a measured property associated with a carbon nanostructure layer to an amount of particulate matter from an exhaust stream of the engine, wherein the carbon nanostructure includes a plurality of carbon nanostructures, and adjusting engine operation based on the amount of particulate matter.

Abstract: A method of monitoring a performance of an oxygen sensor is disclosed. One embodiment comprises determining a first air/fuel ratio from a signal from an exhaust oxygen sensor; determining a second air/fuel ratio from a temperature upstream of the particulate filter, a pressure differential across the particulate filter and one or more of an airflow into the engine and a fuel flow into the engine; comparing the first air/fuel ratio and the second air/fuel ratio; and diagnosing an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second air/fuel ratio.

Abstract: A method for operating an engine comprises correlating a measured property associated with a carbon nanostructure layer to an amount of particulate matter from an exhaust stream of the engine. In this way, engine operation may be adjusted based on an amount of sensed particulate matter.

Abstract: A particulate filter regeneration system is provided. In an example, the particulate filter regeneration system may be provided for use in an exhaust stream of an engine for filtering particulate. The particulate filter regeneration system may include an exhaust inlet, an exhaust chamber coupled downstream of the exhaust inlet, an exhaust outlet, and a flow-through wall coupled between the exhaust chamber and the exhaust outlet. The particulate filter regeneration system may further include a heater for heating the particulate filter regeneration system to enable particulate combustion and a bypass coupled to the exhaust chamber for selectively opening a filter regeneration pathway to remove accumulated particulate.

Abstract: In one example, a method of operating an engine having a diesel particulate filter in a vehicle, the particulate filter having a length and depth, includes performing particulate filter regeneration in response to temperature variation across the length and/or depth of the particulate filter.

Abstract: A method of monitoring a performance of an oxygen sensor is disclosed. One embodiment comprises determining a first air/fuel ratio from a signal from an exhaust oxygen sensor; determining a second air/fuel ratio from a temperature upstream of the particulate filter, a pressure differential across the particulate filter and one or more of an airflow into the engine and a fuel flow into the engine; comparing the first air/fuel ratio and the second air/fuel ratio; and diagnosing an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second air/fuel ratio.

Abstract: A method of operating a diesel engine and an emission control system including a diesel particulate filter comprising of The inventors herein have realized that accurate particulate matter information for controlling processes and parameters may be realized by a method for operating an engine comprising of correlating a measured property associated with a carbon nanostructure layer to an amount of particulate matter from an exhaust stream of the engine, wherein the carbon nanostructure includes a plurality of carbon nanostructures, and adjusting engine operation based on the amount of particulate matter.