Heater particularly for a motor vehicle hvac system

Abstract

A motor vehicle HVAC unit includes a housing, preferably a fan, preferably a coolant evaporator for cooling air to be supplied to the vehicle interior, at least two electric resistance heaters for heating the air to be supplied to the vehicle interior and at least one delay circuit, preferably two delay circuits. The at least two electric resistance heaters are suppliable with electric current, and a device is provided for supplying current to at least one of the at least two electric resistance heaters with a time delay relative to another electric resistance heater, and during the turning on or supplying current to the electric resistance heaters a small maximum current peak requirement is to occur at low technical expenditures.

1 . A heater comprising:
 at least two electric resistance heaters for heating the air to be supplied to the vehicle interior, whereby the at least two electric resistance heaters can be supplied with electric current, and   a device for supplying current to at least one electric resistance heater with a time delay relative to another electric resistance heater,   
       wherein 
       the device comprises at least one delay circuit, preferably two delay circuits. 
     
     
         2 . The heater according to  claim 1 , wherein the at least one delay circuit is at least one, particularly exclusively, analog delay circuit and/or the at least one delay circuit has no processor and/or no program can be run by the at least one delay circuit and/or the at least one delay circuit is an electrical and/or electronic circuit, particularly without a processor. 
     
     
         3 . The heater according to  claim 1 , wherein the at least one delay circuit comprises at least one capacitor and/or at least one resistor. 
     
     
         4 . The heater according to  claim 3 , wherein the at least one delay circuit comprises exclusively at least one capacitor and/or at least one resistor as electric and/or electronic components. 
     
     
         5 . The heater according to  claim 1 , wherein the at least two electric resistance heaters can be supplied with electric current in pulse width modulation. 
     
     
         6 . The heater according to  claim 5 , wherein a first one of the at least two electric resistance heaters can be supplied with pulse-width-modulated current delayed in time relative to another one of the at least two electric resistance heaters with the at least one delay circuit. 
     
     
         7 . The heater according to  claim 1 , wherein at least one of the at least two electric resistance heaters is at least one PTC heater. 
     
     
         8 . The heater according to  claim 1 , wherein the at least two electric resistance heaters are connected electrically parallel. 
     
     
         9 . The heater according to  claim 8 , wherein each of the parallel connected electric resistance heaters are each connected to a parallel power line and the parallel power lines are connected to a central power line. 
     
     
         10 . The heater according to  claim 8 , wherein in parallel connected electric resistance heaters one delay circuit each is connected in series to the parallel connected electric resistance heaters. 
     
     
         11 . The heater according to  claim 10 , characterized in that at least two delay circuit devices are connected parallel and/or in series. 
     
     
         12 . A method for operating a heater, particularly for a vehicle HVAC system according to  claim 1 , comprising the steps:
 conduction of electric current through at least two electric resistance heaters,   preferably conduction of air through the heater,   generation of thermal energy by the at least two electric resistance heaters by converting electrical energy into thermal energy,   preferably the transfer of the thermal energy generated by the at least two electric resistance heaters to the air to be heated, so that the air becomes heated, whereby   during the supplying of current to the at least two electric resistance heaters, at least one electric resistance heater is supplied with current delayed in time relative to another electric resistance heater, in order to reduce the maximum current peak requirement for the at least two electric resistance heaters during the supplying of current and/or turning on of the at least two electric resistance heaters,   
       wherein the current is delayed in an analog manner and/or the current is delayed without a program or software being run. 
     
     
         13 . The method according to  claim 12 , wherein the current is delayed exclusively in an analog manner, particularly by at least one delay circuit. 
     
     
         14 . The method according to  claim 12 , wherein the current passed through the at least two electric resistance heaters is pulse-width-modulated and preferably the pulse width modulation is changed, particularly the turn-on and turn-off times are changed, in order to control and/or to regulate the electric power of the at least two electric resistance heaters. 
     
     
         15 . The method according to  claim 12 , wherein the current is delayed by at least one delay circuit in each case for one electric resistance heater.