Exhaust aftertreatment burner with preheated combustion air

A burner for an exhaust aftertreatment system may include a housing assembly and an ignition device. The housing assembly may include an inner shell surrounded by intermediate and outer shells. The inner shell may at least partially define a combustion chamber. The housing assembly may include an airflow passage having an opening extending through the outer shell. The airflow passage may extend between the outer shell and the intermediate shell as well as between the intermediate shell and the inner shell. The airflow passage may provide fluid communication between the opening and the combustion chamber. The ignition device may be at least partially disposed within the housing assembly and may ignite fuel received from a fuel source and air received from the airflow passage to produce a flame in the combustion chamber. The airflow passage may be in a heat transfer relationship with the flame in the combustion chamber.