In a diesel engine and exhaust aftertreatment system, a controller is arranged to control operation of the engine to obtain a first set of exhaust characteristics and to control a fuel injector to inject fuel upstream of a DPF at a first rate of injection until at least one condition is attained, and, after the at least one condition is attained, to control the fuel injector so that a rate of fuel injection is reduced and to contra! operation of the engine to obtain a second set of exhaust characteristics so that regeneration of the DPF occurs. At least one characteristic of the first and second sets of characteristics beina, different. A method for treating, diesei engine exhaust is also disclosed.