Abstract: The multiple actuator for an electromechanically actuated valve has a housing and a plurality of armature shafts extending through the housing. Each of the armature shafts carry an armature, and two electromagnets which both lie inside the housing. Two springs act on each armature, forcing it into a position of repose between the electromagnets. This configuration makes optimum use of the available basic area above a valve which is to be driven. The armature has a maximum surface area, and optimum dissipation of heat through thermal conduction is possible via the corresponding housing underside.

Abstract: The invention provides the replacing of the known "macroscopic" processes by a "microscopic" approach control strategy for an NOx accumulator. The regeneration phases after approximately 30 seconds of a lean operation, which last approximately one second in the state of the art, is replaced by a rich operating cycle after a sequence of lean ones. The number of lean operating cycles which can be carried out before a regenerating operating cycle depends on the combustion process of the internal-combustion engine as well as on the construction and the volume of the catalyst.