Abstract: Methods and systems are provided for estimation of a volume of liquid diesel exhaust fluid (DEF) contained within a DEF tank. In one example, a method for the estimation of the volume of liquid DEF in a DEF tank during DEF freezing conditions may include activating a heater contained within the DEF tank, and then switching estimation of the volume of liquid DEF via a first transfer function to estimation of the volume of liquid DEF via a second transfer function.

Abstract: Methods and systems for monitoring a NOx sensor for a NOx offset value are described. In one example, the NOx offset value may be based on a minimum NOx concentration observed over an entire drive of a vehicle. The NOx offset monitor may be inhibited in response to inferring or detecting a presence of NH3 in an exhaust system.

Abstract: Methods and systems for monitoring a NOx sensor for a NOx offset value are described. In one example, the NOx offset value may be based on a minimum NOx concentration observed over an entire drive of a vehicle. The NOx offset monitor may be inhibited in response to inferring or detecting a presence of NH3 in an exhaust system.

Abstract: Methods and systems are provided for estimation of a volume of liquid diesel exhaust fluid (DEF) contained within a DEF tank. In one example, a method for the estimation of the volume of liquid DEF in a DEF tank during DEF freezing conditions may include activating a heater contained within the DEF tank, and then switching estimation of the volume of liquid DEF via a first transfer function to estimation of the volume of liquid DEF via a second transfer function.

Abstract: Systems and methods are described for performing a diagnostic on an exhaust gas aftertreatment system. A gas entry parameter into a portion of an exhaust system of an engine is determined. In response to determining that the gas entry parameter is less than the predetermined threshold, a level of NH3 in the exhaust gas is determined. In response to determining that the level of NH3 is above a threshold value, degradation of a particulate filter of the exhaust gas aftertreatment system is indicated.

Abstract: Methods and systems for operating an engine that includes a controller and a NOx sensor are described. In one example, output of the NOx sensor is selectively made available to software modules within the controller when an offset in NOx sensor output is not expected. If the offset in NOx sensor output is expected, the NOx sensor output may not be made available to the software modules.

Abstract: Systems and methods are described for performing a diagnostic on an exhaust gas aftertreatment system. A gas entry parameter into a portion of an exhaust system of an engine is determined. In response to determining that the gas entry parameter is less than the predetermined threshold, a level of NH3 in the exhaust gas is determined. In response to determining that the level of NH3 is above a threshold value, degradation of a particulate filter of the exhaust gas aftertreatment system is indicated.

Abstract: Methods and systems for operating an engine that includes a controller and a NOx sensor are described. In one example, output of the NOx sensor is selectively made available to software modules within the controller when an offset in NOx sensor output is not expected. If the offset in NOx sensor output is expected, the NOx sensor output may not be made available to the software modules.

Abstract: Methods and systems for operating an engine with a pump that is driven via the engine are described. In one example, start of opening of an injector that supplies a fluid to an engine exhaust system is timed based on a period of the pump so that the output of the fluid injector may be repeatable in the presence of fluid pressure oscillations that are periodic with pump rotation.

Abstract: Methods and systems for operating an engine with a pump that is driven via the engine are described. In one example, start of opening of an injector that supplies a fluid to an engine exhaust system is timed based on a period of the pump so that the output of the fluid injector may be repeatable in the presence of fluid pressure oscillations that are periodic with pump rotation.

Abstract: A method of cleaning an EGR valve operatively connected to an exhaust flow from an engine includes determining when cleaning is required, and when cleaning is required, operating the engine in a high temperature mode in which the temperature of exhaust gas exiting the engine is increased while producing a flow of exhaust gas having a low unburnt hydrocarbon content. The method further includes opening the EGR valve to allow hot exhaust gas to flow therethrough so as to remove combustion by-products that are fouling the EGR valve. Furthermore, the method includes producing an estimate of accumulated combustion by-product fouling of the EGR valve. The estimate is then used to determine whether and when to clean the EGR valve.

Abstract: A method of cleaning an EGR valve operatively connected to an exhaust flow from an engine includes determining when cleaning is required, and when cleaning is required, operating the engine in a high temperature mode in which the temperature of exhaust gas exiting the engine is increased while producing a flow of exhaust gas having a low unburnt hydrocarbon content. The method further includes opening the EGR valve to allow hot exhaust gas to flow therethrough so as to remove combustion by-products that are fouling the EGR valve. Furthermore, the method includes producing an estimate of accumulated combustion by-product fouling of the EGR valve. The estimate is then used to determine whether and when to clean the EGR valve.

Abstract: A method for predicting the future operation of a vehicle is disclosed which uses stored data representative of commonly followed routes to predict the future operation of the vehicle for the current trip. By establishing that the route currently being followed is comparable to one of the commonly followed routes, information relating to that “common route” is then used to predict the future operation of the vehicle for the current trip.

Abstract: A method of predicting the future use of a vehicle or an engine of the vehicle is used to evaluate whether NOx slippage from a lean NOx trap is likely to occur during a current drive cycle and also for scheduling when favorable conditions are likely to exist to purge the lean NOx trap before the slippage of NOx from the lean NOx trap is expected to occur.

Abstract: A method of predicting the future use of a vehicle or an engine of the vehicle is used to evaluate whether NOx slippage from a lean NOx trap is likely to occur during a current drive cycle and also for scheduling when favorable conditions are likely to exist to purge the lean NOx trap before the slippage of NOx from the lean NOx trap is expected to occur.

Abstract: A method for predicting the future operation of a vehicle is disclosed which uses stored data representative of commonly followed routes to predict the future operation of the vehicle for the current trip. By establishing that the route currently being followed is comparable to one of the commonly followed routes, information relating to that ‘common route’ is then used to predict the future operation of the vehicle for the current trip.

Abstract: Methods for monitoring and detecting undesired exotherms which may occur in an exhaust aftertreatment system coupled to a lean burning combustion engine are described. In one particular approach, an undesired exotherm may be indicated based on an expected oxygen depletion along a length of an exhaust aftertreatment system in the direction of exhaust gas flow of exhaust gas. For example, during DPF regeneration, a certain amount of oxygen is expected to be utilized for removing soot. If less oxygen is actually found in the exhaust downstream of the exhaust system, then an undesired exotherm may be present, as unintended reductant may be present in the exhaust and reacting exothermically with oxygen. Various mitigation actions may then be initiated in response to the indication of an undesired exotherm.

Abstract: Methods for monitoring and detecting undesired exotherms which may occur in an exhaust aftertreatment system coupled to a lean burning combustion engine are described. In one particular approach, an undesired exotherm may be indicated based on an expected oxygen depletion along a length of an exhaust aftertreatment system in the direction of exhaust gas flow of exhaust gas. For example, during DPF regeneration, a certain amount of oxygen is expected to be utilized for removing soot. If less oxygen is actually found in the exhaust downstream of the exhaust system, then an undesired exotherm may be present, as unintended reductant may be present in the exhaust and reacting exothermically with oxygen. Various mitigation actions may then be initiated in response to the indication of an undesired exotherm.