Air conditioning installation with activated carbon filter

#The invention relates to an air-conditioning installation with an activated carbon filter for cleaning the air to be supplied to the interior of a motor vehicle, in which a device is provided for cleaning by heating of the filter and the air therein, and air laden with by-products can be driven out of the filter by a cleaning airflow.

#It is known to equip air-conditioning installations of motor vehicles with filters, particularly with activated carbon filters. The filters clean the air being supplied to the vehicle interior of strongly smelling and/or toxic components. However, the absorbing power of activated carbon drops off over time, so that the activated carbon has to be cleaned or exchanged. Because the exchanging of the activated carbon filter, particularly with motor vehicles, is associated with high expenditure and high cost, ways for effective regeneration of the activated carbon are sought.

#It is known, for example, to install a heating device, on the air intake side, in series with the activated carbon filter. The heating device heats up the airflow through the filter and hence the filter itself, and which leads to a desorption of the residues in the filter. The contaminated airflow can then be led away to the environment. The disadvantage of this series-connected heating it is that the cleaning takes place in an adiabatic process. Because the airflow is cooled down on passing through the filter by vaporising of the contamination, the desorption process is longer and hence the external energy consumption for the blower is comparatively high.

#Preferred embodiments of the invention will now be described with reference to FIGS. 1 to 4 of the accompanying drawings, in which:

#FIG. 1: shows a section through the blower duct of an air-conditioning installation,

#FIG. 2a and 2b show a side view and a top view respectively of an activated carbon filter with heating strip,

#In the various figures, like reference numerals indicate like parts.

#A cross section through the blower duct 1 of an air-conditioning installation is depicted in FIG. 1. The blower 2 integrated into the air-conditioning installation produces an airflow 3, which before entry into the air-conditioning installation and into the interior of a motor vehicle is led to a filter, here a solid block of activated carbon 4, for cleaning. A heating device 5, which can be supplied with a voltage via the connections 6, is arranged in the filter 4, in physical contact with the activated carbon. By means of the regulated heating device 5 of about 500 W, the filter 4 can be heated uniformly to a temperature of at least 80° C., so that with an appropriately adapted airflow 3 effective cleaning of the filter 4 takes place. A temperature probe 10 is fitted to the filter 4 for monitoring the temperature.

#An outlet aperture 8 is provided in the blower duct 1 on the outflow side after the filter 4 for leading out the contaminated air 7, and can be closed off by means of a swinging flap 9. In the present instance the outlet aperture 8 is open, so that the airflow 7 is led away to the environment. In this way the flap 9, in the position depicted, closes off the air duct 11 leading to the heating or air-conditioning installation. By virtue of the isothermal cleaning process in accordance with the invention, the contaminated air 7 leaving the filter is at approximately the same temperature as the heating device itself.