Methods and systems for operating an engine that includes a catalyst and a particulate filter are described. In one example, release of reductant from an injector may be determined according to a plurality of metrics so that reliability of a release indication may be improved. In addition, operation of an engine may be adjusted responsive to the release indication so that exhaust system temperatures may be maintained.

An aftertreatment system (100) connected downstream an internal combustion engine arrangement (102) for receiving exhaust gases conveyed from the internal combustion engine arrangement (102) during operation thereof, wherein the aftertreatment system comprises first and second catalytic devices in series, wherein a gap is there between.

A heater is provided that includes at least one resistive heating element having a material with a non-monotonic resistivity vs. temperature profile and exhibiting a negative dR/dT characteristic over a predetermined operating temperature range along the profile. The heater can include a plurality of circuits disposed in a fluid path to heat fluid flow.

System and methods are described for optimizing exhaust flow rate and temperature during specified operational periods warm-up and keep-warm conditions, by minimizing or maximizing heat flux during those specified operational periods.

An apparatus includes circuitry configured to calculate a temperature of exhaust flowing into an exhaust after-treatment system as a first exhaust temperature, calculate a temperature of exhaust flowing out from the exhaust after-treatment system as a second exhaust temperature, calculate a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature, and judge if the exhaust after-treatment system is in a removed state removed from the exhaust passage based on a difference between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature.

A control system for an engine including a turbocharger disposed downstream of a plurality of cylinders. The control system includes an engine sensor configured to generate a signal indicative of an operational characteristic of the engine. The control system includes a first valve configured to control exhaust flow through a first set of cylinders from the plurality of cylinders. The control system includes a second valve configured to control exhaust flow through a second set of cylinders from the plurality of cylinders. The control system includes a controller communicably coupled to the engine sensor, the first valve, and the second valve. The controller is configured to receive the signal generated by the engine sensor. The controller is configured to actuate the first valve and the second valve based on the received signal. The first valve and the second valve are actuated to adjust exhaust flow received by the turbocharger.

An intake system for use with an internal combustion engine having one or more cylinders. The intake system including a compressor assembly having an inlet and an outlet, and where the outlet is configured to be open to and in fluid communication with at least one of the one or more cylinders. The intake system also includes a passageway extending between and in fluid communication with the inlet and the outlet and configured to direct a first flow of gasses and a controller in operable communication with the compressor assembly. Where the intake system is operable in a first mode in which the majority of gasses of the first flow of gasses flow through the passageway toward the outlet, and a second mode in which the majority of gasses of the first flow of gasses flow through the passageway toward the inlet.

Disclosed is a method for control of an activation of a fluid sensitive sensor of an exhaust treatment system arranged for treating an exhaust stream, which includes: determining an exhaust temperature and an exhaust mass flow for the exhaust stream; determining if there is liquid fluid present in the exhaust stream at the fluid sensitive sensor, respectively, based on: 1) an elimination time function, wherein the elimination time function is based on the determined exhaust temperature and the determined exhaust mass flow; and 2) a corresponding lengths of a time period needed to eliminate a predetermined amount of liquid fluid from the exhaust stream; and controlling an activation of said fluid sensitive sensor based on the determination of if there is liquid fluid present in the exhaust treatment system at the fluid sensitive sensor.

A method of controlling an exhaust system for a diesel engine comprises providing an aftertreatment system comprising a first catalyst and a diesel exhaust fluid injection system, determining a preliminary dose of a diesel exhaust fluid of the diesel exhaust fluid injection system based on an incoming exhaust gas flow and an exhaust gas temperature, determining an NH.sub.3 factor based on incoming exhaust gas oxygen concentration and the incoming exhaust gas flow temperature, and determining a final dose of diesel exhaust fluid by multiplying the preliminary dose of diesel exhaust fluid by the NH.sub.3 factor.

A method, system, and apparatus relating to operating an internal combustion engine include steps or features for determining a performance threshold of a particulate filter disposed in an exhaust gas flow of the engine having a set time interval between regeneration events of the particulate filter; determining a rate at which the particulate filter is reaching the performance threshold; and controlling an exhaust gas characteristic to control the rate so that the performance threshold is reached at or just before an end of the time interval. In an embodiment, there are steps or features for interpreting a filter condition of the particulate filter; determining a particulate matter load rate of the filter as a function of the condition; determining a limit of an exhaust gas characteristic based on the load rate; and controlling engine operation to control the exhaust gas characteristic to satisfy the limit.