Exhaust aftertreatment system with diagnostic delay

A vehicle comprising:

• an engine producing an exhaust gas;
• an aftertreatment system for treating the exhaust gas, and including a selective catalytic reduction (SCR) device and a particulate filter;
• wherein the particulate filter is configured to regenerate when the exhaust gas is heated above a regeneration temperature;
• at least one NOx sensor operatively connected to the aftertreatment system and adapted to determine an amount of NOx in the exhaust gas;
• a temperature sensor for sensing a temperature of the exhaust gas;
• a controller operatively connected to the NOx sensor;
• wherein the controller is configured to determine whether a predefined amount of time at a predefined temperature has elapsed and whether a predefined number of particulate filter regenerations has occurred;
• wherein the controller does not enable the NOx sensor when the engine is started until at least one predefined operating parameter is met and one or more entry conditions are each satisfied;
• and
• wherein the one or more entry conditions include a first entry condition, the first entry condition being satisfied when the predefined number of particulate filter regenerations has occurred.

A method for controlling operation of an aftertreatment system in a vehicle having an engine producing exhaust gas, the method comprising:

• providing a selective catalytic reduction (SCR) device and a particulate filter in the aftertreatment system;
• providing at least one NOx sensor for the aftertreatment system, the NOx sensor configured to determine an amount of NOx in the exhaust gas;
• disabling the NOx sensor when the engine is started;
• heating the exhaust gas in order to regenerate the particulate filter;
• sensing a temperature of the exhaust gas;
• determining whether a predefined amount of time at a predefined temperature for the exhaust gas has elapsed and whether a predefined number of particulate filter regenerations has occurred;
• enabling the NOx sensor when at least one predefined operating parameter is met and one or more entry conditions are each satisfied;
• wherein the one or more entry conditions include a first entry condition and a second entry condition;
• and
• wherein the first entry condition is satisfied when the predefined amount of time at the predefined temperature has elapsed and the second entry condition is satisfied when the predefined number of particulate filter regenerations has occurred.