Combustion chamber assembly unit for a fuel-operated vehicle heating device, comprising: - a combustion chamber housing with a combustion chamber bottom and with a combustion chamber circumferential wall elongated in the direction of a housing longitudinal axis and arranged enclosing the housing longitudinal axis, wherein the combustion chamber bottom and the combustion chamber circumferential wall define a combustion chamber, - a porous evaporator medium on an inner side of the combustion chamber circumferential wall or/and of the combustion chamber bottom, which inner side faces the combustion chamber, - a fuel feed line for feeding liquid fuel into the porous evaporator medium, - a first combustion zone with a first combustion air feed device associated with the combustion chamber bottom for feeding primary combustion air (V P) into the combustion chamber, wherein the porous evaporator medium is arranged in the first combustion zone, - a second combustion zone following the first combustion zone in the direction of the housing longitudinal axis with a second combustion air feed device associated with the combustion chamber circumferential wall for feeding secondary combustion air (V S) into the combustion chamber at an axially spaced location from the first combustion zone, wherein the first combustion air feed device comprises a combustion air introduction attachment projecting in the direction of the combustion chamber at the combustion chamber bottom, wherein a plurality of first combustion air introduction openings (38, 40) are provided in a circumferential wall and in a bottom of the combustion air introduction attachment, which bottom is offset in the direction of the housing longitudinal axis in relation to the combustion chamber bottom, and wherein the second combustion air feed device comprises a plurality of second combustion air introduction openings in an area of the combustion chamber circumferential wall, which area is located at an axially spaced location in relation to the bottom of the combustion air introduction attachment, wherein the second combustion air introduction openings are arranged at an axially spaced location from the porous evaporator medium, characterized in that the porous evaporator medium extends on an inner side of the combustion chamber circumferential wall, starting from the combustion chamber bottom, axially beyond the combustion air introduction attachment. - a combustion chamber housing with a combustion chamber bottom and with a combustion chamber circumferential wall elongated in the direction of a housing longitudinal axis and arranged enclosing the housing longitudinal axis, wherein the combustion chamber bottom and the combustion chamber circumferential wall define a combustion chamber, - a porous evaporator medium on an inner side of the combustion chamber circumferential wall or/and of the combustion chamber bottom, which inner side faces the combustion chamber, - a fuel feed line for feeding liquid fuel into the porous evaporator medium, - a first combustion zone with a first combustion air feed device associated with the combustion chamber bottom for feeding primary combustion air (V P) into the combustion chamber, wherein the porous evaporator medium is arranged in the first combustion zone, - a second combustion zone following the first combustion zone in the direction of the housing longitudinal axis with a second combustion air feed device associated with the combustion chamber circumferential wall for feeding secondary combustion air (V S) into the combustion chamber at an axially spaced location from the first combustion zone, wherein the first combustion air feed device comprises a combustion air introduction attachment projecting in the direction of the combustion chamber at the combustion chamber bottom, wherein a plurality of first combustion air introduction openings (38, 40) are provided in a circumferential wall and in a bottom of the combustion air introduction attachment, which bottom is offset in the direction of the housing longitudinal axis in relation to the combustion chamber bottom, and