Abstract: Methods and systems are provided for detecting NOx sensor degradation based on results from a NOx sensor self-diagnostic (SD) test. In one example, a method may comprise: determining that a nitrogen oxide (NOx) sensor is degraded if outputs received from the sensor via a CAN bus during a self-diagnostic test are outside a threshold range. Additionally, only outputs received from the sensor during a self-diagnostic (SD) test performed after a first completed SD test after a key-off event, where the outputs are generated under conditions where a temperature at the sensor is less than a threshold, and an oxygen concentration is within a threshold range may be used to determine if the sensor is degraded.

Abstract: Methods and systems are provided for detecting NOx sensor degradation based on results from a NOx sensor self-diagnostic (SD) test. In one example, a method may comprise: determining that a nitrogen oxide (NOx) sensor is degraded if outputs received from the sensor via a CAN bus during a self-diagnostic test are outside a threshold range. Additionally, only outputs received from the sensor during a self-diagnostic (SD) test performed after a first completed SD test after a key-off event, where the outputs are generated under conditions where a temperature at the sensor is less than a threshold, and an oxygen concentration is within a threshold range may be used to determine if the sensor is degraded.

Abstract: Various systems and methods for detecting exhaust reductant injector degradation based on an exhaust NOx sensor are disclosed. In one example, degradation of the reductant injector is indicated when an actual NOx sensor output differs from an expected NOx sensor output by more than a threshold amount under engine off conditions.

Abstract: Various systems and methods for detecting exhaust reductant injector degradation based on an exhaust NOx sensor are disclosed. In one example, degradation of the reductant injector is indicated when an actual NOx sensor output differs from an expected NOx sensor output by more than a threshold amount under engine off conditions.

Abstract: A method to deliver fuel during a start for an internal combustion engine is described. The method provides individual cylinder fuel control based on the number of fueled cylinder events. The method offers improved engine emissions while maintaining engine run-up performance.

Abstract: A method to deliver spark during a start for an internal combustion engine is described. The method provides individual cylinder spark angle control based on the number of fueled cylinder events. The method offers improved engine emissions while maintaining engine speed run-up performance.

Abstract: A method to deliver fuel during a start for an internal combustion engine is described. The method provides individual cylinder fuel control based on the number of fueled cylinder events. The method offers improved engine emissions while maintaining engine run-up performance.

Abstract: A method to deliver spark during a start for an internal combustion engine is described. The method provides individual cylinder spark angle control based on the number of cylinders after synchronization between engine timing and an engine controller are achieved. The method offers improved engine emissions while maintaining engine speed run-up performance.

Abstract: A method to deliver spark during a start for an internal combustion engine is described. The method provides individual cylinder spark angle control based on the number of fueled cylinder events. The method offers improved engine emissions while maintaining engine speed run-up performance.

Abstract: A method to deliver fuel during a start for an internal combustion engine is described. The method provides individual cylinder fuel control based on the number of fueled cylinder events. The method offers improved engine emissions while maintaining engine run-up performance.

Abstract: A method to deliver spark during a start for an internal combustion engine is described. The method provides individual cylinder spark angle control based on the number of cylinders after synchronization between engine timing and an engine controller are achieved. The method offers improved engine emissions while maintaining engine speed run-up performance.

Abstract: A method to deliver spark during a start for an internal combustion engine is described. The method provides individual cylinder spark angle control based on the number of fueled cylinder events. The method offers improved engine emissions while maintaining engine speed run-up performance.

Abstract: A method and system are provided for determining a present value representative of the quantity of oxygen that is stored in an emission control device receiving exhaust gas generated by an internal combustion engine, as well as a present value for the maximum capacity of the device to store a selected constituent gas of the exhaust gas. The resulting values are advantageously used for adaption of predetermined values for controlling device fill and purge times when operating in an open-loop control mode, whereby open-loop device operation is optimized to reflect changes in device operating conditions.

Abstract: A system and method are provided for closed-loop monitoring of temperature within a vehicle emission control device to control air-fuel ratio (AFR) and corresponding production of exotherm to accurately maintain a desired temperature range. A temperature sensor is positioned within the emission control device to provide a direct measurement of temperature within the device. Inlet temperature can be either directly measured or estimated using a temperature model. Actual temperature within the device is estimated as a function of the inlet and measured temperatures. The estimated actual temperature is used to modify the AFR in the exhaust gases flowing through the emission control device.

Abstract: A method and system for optimizing the purging of a constituent gas of a vehicle engine's generated exhaust gas from an emission control device is disclosed wherein the amplitude of the output signal generated by a downstream switching oxygen sensor, and the time response of the sensor, is used to iteratively adjust a current purge time to obtain an optimized purge time.

Abstract: A system and method for optimizing the regeneration cycle of an emission control device, such as a lean NOx trap, is disclosed wherein the device is filled to a predetermined fraction of its existing capacity and is then completely emptied during a device purge. As device capacity is substantially reduced, as indicated by the actual fill time becoming equal to or less than a predetermined minimum fill time, a device desulfation event is performed to attempt to restore device capacity. A programmed computer controls the fill and purge times based on the amplitude of the voltage of a switching-type oxygen sensor and the time response of the sensor. The frequency of the purge, which ideally is directly related to the device capacity depletion rate, is controlled so that the device is not filled beyond the storage capacity limit.

Abstract: A method of optimizing vehicle emissions during lean engine operation is disclosed wherein an emission control device receiving engine exhaust gases is filled with one or more constituent gases of the exhaust gas to a predetermined fraction of the device storage capacity, and is then completely emptied during a subsequent purge. As the device storage capacity is substantially reduced, as indicated by an actual fill time becoming equal to or less than a predetermined minimum fill time, a device regeneration cycle is performed to attempt to restore device capacity. A programmed computer controls the fill and purge times based on the amplitude of the voltage of a switching-type oxygen sensor and the time response of the sensor. The frequency of the purge, which ideally is directly related to the device capacity depletion rate, is controlled so that the device is not filled beyond its storage capacity limit.

Abstract: A method and system are provided for determining a present value representative of the quantity of oxygen that is stored in an emission control device receiving exhaust gas generated by an internal combustion engine, as well as a present value for the maximum capacity of the device to store a selected constituent gas of the exhaust gas. The resulting values are advantageously used for adaption of predetermined values for controlling device fill and purge times when operating in an open-loop control mode, whereby open-loop device operation is optimized to reflect changes in device operating conditions.

Abstract: A method and system are provided for adaptive control of a purge time and a fill time for an emission control device used to reduce emission of a selected constituent gas, such NOx, of an engine's generated exhaust gas, with optimization and adapting of stored values to reflect changes in device operating conditions. The invention determines a present value representative of the quantity of oxygen stored in the device, as well as a present value for the maximum device NOx-storage capacity to provide real-time adjustment of purge and fill time to achieve optimum overall operation of the device. The invention also periodically determines actual fill times which corresponding to optimal fill times to generate adaptive values for use during normal open-loop control.

Abstract: A method and system for optimizing the purging of a constituent gas of a vehicle engine's generated exhaust gas from an emission control device is disclosed wherein the amplitude of the output signal generated by a downstream switching oxygen sensor, and the time response of the sensor, is used to iteratively adjust a current purge time to obtain an optimized purge time.