A mobile heating device operated with liquid fuel is provided, having: a combustion chamber (2) comprising a combustion air inlet (3), wherein the combustion chamber adjacent to the combustion air inlet (3) comprises a widening portion (20) the cross-section of which widens with increasing distance from the combustion air inlet (3) and in which in operation combustion air and fuel are converted in a flaming combustion; a fuel supply which is arranged such that fuel is supplied into the widening portion (20); and an air guide device (6) being adapted to feed combustion air into the widening portion (20) with a flow component directed in the circumferential direction such that an axial recirculation region (RB) forms in the widening portion (20) in which gases flow in the direction towards the combustion air inlet (3) oppositely to a main flow direction (H). The combustion chamber (2) is fluidically sectioned into a primary combustion zone (PZ) and a secondary combustion zone (SZ). The primary combustion zone (PZ) comprises the widening portion (20) and the recirculation region (RB). The secondary combustion zone (SZ) is provided with a secondary combustion air inlet (23) in such a manner that a higher air-fuel ratio λ than in the primary combustion zone (PZ) forms in the secondary combustion zone (SZ).

An evaporator assembly (10), in particular for a fuel-operated vehicle heater (12), comprising a pot-like evaporator reception (14), an evaporator body (16) inserted into the pot-like evaporator reception (14), a plate-like designed hold-down element (18), which is fixed to the evaporator reception (14) and fixes the evaporator body (16) in the evaporator reception (14), and wherein the plate-like designed hold-down element (18) has at least one retaining claw (22), which has an upper part (26) on an upper side (24) of the plate-like designed hold-down element (18) and a lower part (30) on a lower side (28) of the plate-like designed hold-down element (18), wherein the upper part (26) and the lower part (30) point away from the plate-like designed hold-down element (18).

An evaporator assembly (10), in particular for a fuel-operated vehicle heater (12), comprising a pot-like evaporator reception (14), an evaporator body (16) inserted into the pot-like evaporator reception (14), a plate-like designed hold-down element (18), which is fixed to the evaporator reception (14) and fixes the evaporator body (16) in the evaporator reception (14), and wherein the plate-like designed hold-down element (18) has at least one retaining claw (22), which has an upper part (26) on an upper side (24) of the plate-like designed hold-down element (18) and a lower part (30) on a lower side (28) of the plate-like designed hold-down element (18), wherein the upper part (26) and the lower part (30) point away from the plate-like designed hold-down element (18).

The ignition characteristics of a fuel are adjusted using a unit which has a distribution zone, a oxidation zone and a conversion zone. Fuel is distributed in the distribution zone having a distribution structure. A portion of the fuel is oxidised in the oxidation zone with a oxidising agent on a catalyst on a catalyst carrier, and a portion of the distributed fuel and/or of another supplied fuel is thermally and/or catalytically converted in the conversion zone. The ignition characteristics of the fuel are adjusted via: the molar ratio of oxygen included in the oxidising agent to the oxygen required for the complete oxidation of the fuel provided; and/or via the pressure in the unit; and/or the dwell time; and/or the temperature. Exhaust emissions, in particular NOx and soot emissions, can be lowered.

The ignition characteristics of a fuel are adjusted using a unit which has a distribution zone, a oxidation zone and a conversion zone. Fuel is distributed in the distribution zone having a distribution structure. A portion of the fuel is oxidised in the oxidation zone with a oxidising agent on a catalyst on a catalyst carrier, and a portion of the distributed fuel and/or of another supplied fuel is thermally and/or catalytically converted in the conversion zone. The ignition characteristics of the fuel are adjusted via: the molar ratio of oxygen included in the oxidising agent to the oxygen required for the complete oxidation of the fuel provided; and/or via the pressure in the unit; and/or the dwell time; and/or the temperature. Exhaust emissions, in particular NOx and soot emissions, can be lowered.

A fuel-operated vehicle heater includes a burner area (12) with a combustion chamber (14); a fuel pump (24); and a combustion air blower (28). A pressure sensor (38) detects a feed back pressure. An actuating unit (36) actuates the fuel pump (24) with a predefined value of a pump operating variable, and actuates the combustion air blower with a predefined value of a blower operating variable. A heater process includes detecting the feed back pressure in case of a feed operating state set during the combustion operation and comparing the detected feed back pressure (P.sub.e) with an expected feed back pressure (P.sub.E) for the set feed operating state. If the detected feed back pressure deviates from the expected feed back pressure the pump operating variable is changed such that the feed back pressure changes toward the expected feed pressure and/or essentially corresponds to the expected feed back pressure.

A fuel-operated vehicle heater includes a burner area (12) with a combustion chamber (14); a fuel pump (24); and a combustion air blower (28). A pressure sensor (38) detects a feed back pressure. An actuating unit (36) actuates the fuel pump (24) with a predefined value of a pump operating variable, and actuates the combustion air blower with a predefined value of a blower operating variable. A heater process includes detecting the feed back pressure in case of a feed operating state set during the combustion operation and comparing the detected feed back pressure (P.sub.e) with an expected feed back pressure (P.sub.E) for the set feed operating state. If the detected feed back pressure deviates from the expected feed back pressure the pump operating variable is changed such that the feed back pressure changes toward the expected feed pressure and/or essentially corresponds to the expected feed back pressure.

A combustion chamber assembly unit for a fuel-operated vehicle heater includes a mixing chamber (20) extending in a direction of a combustion chamber assembly unit longitudinal axis (L) for generating an air/fuel mixture. A fuel feed device (38) feeds fuel to the mixing chamber (20) and a combustion air feed device feeds combustion air to the mixing chamber (20). A diffuser device (22) is arranged downstream in relation to the mixing chamber (20) in the direction of the combustion chamber assembly unit longitudinal axis (L). The fuel feed device (38) includes an evaporator device (36). The combustion air feed device (18) includes a swirling flow generation device (14). The swirling flow generation device (14) is arranged with the evaporator device (36) upstream in relation to the mixing chamber (20) in the direction of the combustion chamber assembly unit longitudinal axis (L).

A combustion chamber assembly unit for a fuel-operated vehicle heater includes a combustion chamber housing, a combustion chamber formed in the combustion chamber housing, an evaporator medium for the absorption of liquid fuel and for the discharge of fuel vapor into the combustion chamber, and a heating/ignition device for heating the evaporator medium or/and for igniting a mixture of fuel and combustion air formed in the combustion chamber. The heating/ignition device includes at least one radiation source for the emission of electromagnetic radiation into the combustion chamber and at least one absorption body for the absorption of electromagnetic radiation emitted into the combustion chamber.

A combustion chamber assembly unit for a fuel-operated vehicle heater includes a combustion chamber housing, a combustion chamber formed in the combustion chamber housing, an evaporator medium for the absorption of liquid fuel and for the discharge of fuel vapor into the combustion chamber, and a heating/ignition device for heating the evaporator medium or/and for igniting a mixture of fuel and combustion air formed in the combustion chamber. The heating/ignition device includes at least one radiation source for the emission of electromagnetic radiation into the combustion chamber and at least one absorption body for the absorption of electromagnetic radiation emitted into the combustion chamber.