Patent ID: 7900441

Claim:
A method of treating engine exhaust comprising: providing an exhaust aftertreatment system comprising: a valve system having a valve input operatively coupled to the engine exhaust, a first valve output, and a second valve output; a precat having a precat input operatively coupled to the said first valve output and a precat output; a NOx adsorber having an adsorber input operatively coupled to said precat output and an adsorber output; a fuel tank operatively coupled to a fuel pump; and the fuel pump having a fuel pump intake operatively coupled to said fuel tank and a fuel pump outlet; at least one first NOx sensor operatively coupled to said valve system output; at least one second NOx sensor operatively coupled to said NOx adsorber output; a soot filter having a soot filter input operatively coupled to coupled to the first NOx adsorber output; a NOx sensor positioned intermediate the first NOx adsorber output and the soot filter; a controller operatively linked to said valve system, said injector, and said fuel pump, said first and second NOx sensors; collecting data on NOx levels from said first NOx sensor and said second NOx sensor; sending data from said NOx sensors to said controller; processing said data from said NOx sensors in said controller; adjusting said valve system to alter flow of exhaust to said precat operatively coupled to said NOx adsorber undergoing regeneration based on signals from said controller; activating said fuel pump based on signals from said controller; pumping fuel to said injector; injecting fuel into the input of said precat; monitoring input from said NOx sensors measuring the level of NOx in exhaust; inactivating said fuel pump by said controller; and adjusting said valve system to increase flow of exhaust to at least partially regenerated NOx adsorber.