Combustion chamber assembly unit for a fuel-operated vehicle heater

A fuel-operated vehicle heater comprising a combustion chamber assembly unit, the combustion chamber assembly unit comprising:

• a mixing chamber configured to generate an air/fuel mixture and extending in a direction of a combustion chamber assembly unit longitudinal axis, the mixing chamber being defined by a mixing chamber circumferential wall extending in the direction of the combustion chamber assembly unit longitudinal axis and enclosing same and having a wall inner side facing the mixing chamber;
• a fuel feed device configured to feed fuel to the mixing chamber, wherein the fuel feed device comprises an evaporator device, the evaporator device comprising a porous evaporator medium covering the wall inner side in at least some areas;
• a combustion air feed device configured to feed combustion air to the mixing chamber, wherein the combustion air feed device comprises a swirling flow generation device arranged with the evaporator device upstream in relation to the mixing chamber in the direction of the combustion chamber assembly unit longitudinal axis;
• and
• a diffuser device arranged downstream in relation to the mixing chamber in the direction of the combustion chamber assembly unit longitudinal axis, the diffuser device comprising a diffuser circumferential wall, the diffuser circumferential wall having a first circumferential wall length area with a smaller internal dimension and a second circumferential wall length area, following downstream of the first circumferential wall length area in the direction of the combustion chamber assembly unit, the second circumferential wall length area having, in at least some areas, an internal dimension greater than the smaller internal dimension of the first circumferential wall length area and increasing along the combustion chamber assembly unit longitudinal axis in the direction away from the first circumferential wall length area.

A fuel-operated vehicle heater combustion chamber assembly unit comprising:

• a mixing chamber structure comprising a mixing chamber structure circumferential wall extending in a direction of a combustion chamber assembly unit longitudinal axis, the mixing chamber structure circumferential wall comprising a mixing chamber structure circumferential wall inner side defining a mixing chamber configured to generate an air/fuel mixture;
• a fuel feed device configured to feed fuel to the mixing chamber, wherein the fuel feed device comprises an evaporator device, the evaporator device comprising a porous evaporator medium covering one or more areas of the mixing chamber structure circumferential wall;
• a combustion air feed device configured to feed combustion air to the mixing chamber, wherein the combustion air feed device comprises a swirling flow generation device arranged with the evaporator device upstream in relation to the mixing chamber in the direction of the combustion chamber assembly unit longitudinal axis;
• and
• a diffuser device arranged downstream in relation to the mixing chamber in the direction of the combustion chamber assembly unit longitudinal axis, the diffuser device comprising a diffuser circumferential wall, the diffuser circumferential wall having a first circumferential wall length area and a second circumferential wall length area following downstream of the first circumferential wall length area in the direction of the combustion chamber assembly unit, the first circumferential wall length area comprising a first internal dimension, wherein one or more areas of the second circumferential wall length area has a second internal dimension, the second internal dimension being greater than the first internal dimension, the second internal dimension increasing along the combustion chamber assembly unit longitudinal axis in the direction away from the first circumferential wall length area.