Patent ID: 8417416
Filing Date: 2013-04-09
Classification: B60H,B60N

Abstract:
1. An electric auxiliary heating unit for a motor vehicle, comprising: at least one PTC heating element for heating the air flowing through the auxiliary heating unit, wherein the air flow through the auxiliary heating unit is selectable; a control unit for adjusting the heating power of the at least one heating element, wherein the control unit adjusts the temperature of the air discharged from the auxiliary heating unit in dependence upon the vehicle speed; a temperature determination unit which determines the cold air temperature of the air to be heated by the auxiliary heating unit, wherein the control unit adjusts the heating power additionally in dependence upon the determined cold air temperature and the selectable air flow rate, and wherein the temperature determination unit determines the cold air temperature on the basis of at least one measured temperature value; and a sensor that measures the cold air temperature and that is arranged in an air intake section of the heating element between a blower for supplying the air to be heated and the heating element; wherein, when the heating power to be generated changes due to a selection of a new air flow rate, the control unit responds to the change by (i) setting the heating power to a value that is less or greater than the heating power assigned to the air flow rate for a predetermined period of time after the change and by (ii) setting the heating power to the value assigned to the air flow rate after the predetermined period of time.