Abstract: A motor vehicle heating system which is provided in a motor vehicle coolant circuit containing a motor vehicle engine, a motor vehicle heater with a heat exchanger and an associated blower, and a fuel operated heating device that is independent of the motor vehicle engine and is connected upstream from the motor vehicle heater, and a process for operating such a motor vehicle heating system, by which the motor vehicle engine in the motor vehicle coolant circuit is heated first to a temperature which is low yet facilitates its starting, and then the coolant is heated so that the motor vehicle heater can provide heat quickly. Until a first predetermined temperature of the coolant is reached, the coolant, is circulated in the complete motor vehicle coolant circuit.

Abstract: A ring channel blower for combustion air conveyance in heaters, preferably motor vehicle heaters. With this ring channel blower, there is a gradual transition from the pressure area to the discharge opening of a ring channel that is covered at a side of the ring channel proximate an impeller by an upstream extending section of a cross piece-shaped interrupter. Suitably, a sickle-shaped or sail-shaped section covering the ring channel is provided which, starting from the inner edge of the ring channel, approximately at the height of the projection of the discharge opening on the ring channel, uniformly tapers in a direction opposite the compression direction in the ring channel of the ring channel blower and ends in a type of rounded tip on the outer edge of the ring channel of the ring channel blower.

Abstract: In a heating device, particularly one intended for use as a vehicle auxiliary heating device, a heat exchanger is provided for a liquid heat exchange medium, which is of a quadrangular, preferably cuboid design, having a planar closed end. Inside the heat exchanger, inner fins are provided defining exhaust gas channels, whose free ends are approximately on a circle whose center is the center axis of the heat exchanger or that of the cylindrical combustion chamber as a transition between the cylindrical combustion chamber and a rectanguloid outer housing which surrounds the heat exchanger. An outer, flat surface of the housing may be formed with a receiver for a control or similar device.