Valve for opening and closing exhaust lines, having - a housing, - a plunger which is arranged in the housing and which is couplable to a drive and which is configured to be moved along a longitudinal axis of the plunger by means of the drive, - a valve seat which is arranged in the housing and which has a valve outlet, and - a valve body which is fixedly connected to the plunger, wherein a sealing element is arranged on the valve body such that, by means of a movement of the plunger, the valve body and the sealing element can be actuated between an open position, in which the valve outlet is opened up, and a closed position, wherein the valve body and the sealing element are configured such that, in the closed position, the valve body and the sealing element each lie sealingly against the valve seat in order to close the valve outlet, - wherein the sealing element is an elastic disc which is configured as a metallic disc or sheet-metal disc, - wherein the elastic disc is of ring-shaped configuration, characterized in that - the valve body has an encircling projection which, in the closed position, lies against a counterpart contact surface, which runs normally with respect to the longitudinal axis, of the valve seat in order to seal off the valve outlet, wherein the encircling projection is of rounded form on the side facing toward the counterpart contact surface, - the elastic disc, in the closed position, is bent elastically in a direction away from the valve seat and lies against the valve seat, and - the elastic disc is, on a side of the valve body which is averted from the valve seat, pressed onto an encircling assembly projection of the valve body and arranged in form-fitting, captive fashion thereon. - a housing, - a plunger which is arranged in the housing and which is couplable to a drive and which is configured to be moved along a longitudinal axis of the plunger by means of the drive, - a valve seat which is arranged in the housing and which has a valve outlet, and - a valve body which is fixedly connected to the plunger, wherein a sealing element is arranged on the valve body such that, by means of a movement of the plunger, the valve body and the sealing element can be actuated between an open position, in which the valve outlet is opened up, and a closed position, wherein the valve body and the sealing element are configured such that, in the closed position, the valve body and the sealing element each lie sealingly against the valve seat in order to close the valve outlet, - wherein the sealing element is an elastic disc which is configured as a metallic disc or sheet-metal disc, - wherein the elastic disc is of ring-shaped configuration, characterized in that - the valve body has an encircling projection which, in the closed position, lies against a counterpart contact surface, which runs normally with respect to the longitudinal axis, of the valve seat in order to seal off the valve outlet, wherein the encircling projection is of rounded form on the side facing toward the counterpart contact surface, - the elastic disc, in the closed position, is bent elastically in a direction away from the valve seat and lies against the valve seat, and - the elastic disc is, on a side of the valve body which is averted from the valve seat, pressed onto an encircling assembly projection of the valve body and arranged in form-fitting, captive fashion thereon.