A drive device for a motor vehicle includes an exhaust pipe and a secondary air device having a first secondary air path which feeds into the exhaust gas pip. Disposed in the first secondary air path is a secondary air pump and a secondary air valve. To compensate, for example, fluctuations in the supply voltage of the secondary air pump, provision is made for arrangement in the secondary air path of a Laval nozzle which can be placed downstream of the secondary air valve.

An exhaust processing system for treating an exhaust gas stream that includes an exhaust duct for directing the exhaust gas stream; a first catalyst positioned within the exhaust duct for receiving the exhaust gas stream flowing therethrough; and an injection system for injecting cooling air and reductant in the exhaust gas stream. The injection system may include: a reductant supply feed for supplying the reductant; a cooling air supply feed for supplying the cooling air; a junction configured at which the reductant supply feed and the cooling air supply feed combine to form a combined supply feed thereafter; and an injector disposed within the exhaust duct to which the combined supply feed connects.

Exhaust aftertreatment assemblies and methods of manufacturing and operating exhaust aftertreatment assemblies. The exhaust aftertreatment assembly includes a reductant delivery device, a reductant source fluidly coupled to the reductant delivery device, a mixing chamber positioned between the reductant delivery device and the reductant source and thereby fluidly coupling the reductant source to the reductant delivery device, and a compressed air source fluidly coupled to the mixing chamber upstream of the mixing chamber with respect to the reductant delivery device. The compressed air source provides compressed air to mix with reductant in the mixing chamber.

An exhaust purification device includes: a filter including an oxygen storage capacity (OSC) material; a secondary air supply passage connected to the exhaust passage upstream of the filter; a secondary air control valve disposed in the secondary air supply passage and configured to provide periodicity to secondary air supplied to the secondary air supply passage; and an engine control unit (ECU), wherein the ECU controls the secondary air control valve so as to supply the secondary air with a predetermined frequency and a maximum amplitude of an oxygen concentration. The secondary air control valve is controlled so that when the frequency of the secondary air is fixed to a value of greater than 0 Hz and less than or equal to 1.5 Hz, the maximum amplitude of the oxygen concentration is greater than 0.50% and less than or equal to 3.0%.