Electric heating device comprising a plurality of heating elements

• US 6,940,050 B2
• Filed: 10/29/2003
• Issued: 09/06/2005
• Est. Priority Date: 10/30/2002
• Status: Expired due to Fees

• Current Assignee: Catem GmbH & Co., KG
• Original Assignee: Catem GmbH & Co., KG
• Inventors: Probst, Frank
• Primary Examiner(s): Walberg, Teresa J.
• Application Number:
  US10/696,724
• Publication Number:
  US 20040256377A1
• Time in Patent Office: 678 Days
• Field of Search: 219/486, 219/492, 219/205, 219/208, 219/483, 219/508, 307/41
• US Class Current: 219/486
• CPC Class Codes: B60H 1/2218 controlling the operation of electric heaters
• CPC Class Codes: F24H 3/0429 For vehicles
• CPC Class Codes: G05D 23/1951 with control of the working time of a temperature controlling device
• CPC Class Codes: H05B 1/0225 actuated by timers
• CPC Class Codes: H05B 1/0236 for vehicles
• CPC Class Codes: H05B 2203/023 Heaters of the type used for electrically heating the air blown in a vehicle compartment by the vehicle heating system
• CPC Class Codes: H05B 3/50 heating conductor arranged in metal tubes, the radiating surface having heat-conducting fins

Abstract

The invention relates to an electric heating device and a method of controlling such a heating device, by means of which homogeneous heating of a heating register is to be achieved. For this purpose, the allocations between the control channels of a control device and the heating elements are varied at predetermined time intervals.

Claims

1. An electric heating device used as an auxiliary heating for motor vehicles comprising:

a plurality of heating elements, which are combined so as to form a heating block, wherein each of said heating elements is controlled separately to heat a particular portion of a total air flow to be heated, the remaining portion of the total air flow being heated only by the remaining heating element; and

a control device which controls the heating power of each of the heating elements, the heating power for each of said heating elements being separately adjustable,

wherein the control changes an allocation of the heating power to each of the heating elements at predetermined time intervals.

2. An electric heating device according to claim 1, wherein the change of allocation represents a permutation or a rotation of the allocations of the respective separately adjusted heating powers to the individual heating elements.

3. An electric heating device according to claim 1, wherein the control device controls at least one of the heating elements through switching over between a maximum heating power and zero power.

4. An electric heating device according to claim 1, wherein the control device controls at least one of the heating elements via a substantially continuously adjustable heating power.

5. An electric heating device according to claim 1, wherein the control device controls one of the heating elements via a continuously adjustable heating power and all the other heating elements through switching over between the maximum heating power and zero power.

6. An electric heating device according to claim 4, wherein the control device controls the at least one heating element, whose heating power is continuously adjustable, via a pulse width modulation.

7. An electric heating device according to claim 5, wherein the control device controls the one heating element, whose heating power is continuously adjustable, via a pulse width modulation.

8. An electric heating device according to claim 7, wherein the predetermined time intervals represent an integer multiple of a period of the pulse width modulation.

9. An electric heating device according to claim 8, wherein the heating device comprises a total of four separately controllable heating elements and the predetermined time intervals are equal to eight times the period of the pulse width modulation.

10. A method of controlling an electric heating device, used especially as an auxiliary heater for motor vehicles, the heating device comprising a plurality of heating elements combined so as to form a heating block, each of said heating elements being adapted to be controlled separately,

controlling the heating power of each of the heating elements separately so that each of said heating elements heats only a portion of the total air flow to be heated, the remainder of the total air flow being healed by the remaining heating elements;

and

changing the allocation of a heating power to each of the heating elements at predetermined time intervals.

11. A method according to claim 10, wherein the step of changing the allocation of a heating power comprises permuting or rotating the allocations of the respective separately adjusted heating powers to the individual heating elements.

12. A method according to claim 10, wherein one of the heating elements is controlled through switching over between the maximum heating power and zero power.

13. A method according to claim 10, wherein at least one of the heating elements is controlled via a substantially continuously adjustable heating power.

14. A method according to claim 10, wherein one of the heating elements is controlled via a continuously adjustable heating power and that all the other heating elements are controlled through switching over between the maximum heating power and zero power.

15. A method according to claim 13, wherein the at least one heating element whose heating power is continuously adjustable is controlled via a pulse width modulation.

16. A method according to claim 14, wherein the at least one heating element whose heating power is continuously adjustable is controlled via a pulse width modulation.

17. A method according to claim 16, wherein predetermined time intervals represent an integer multiple of a period of a pulse width modulation.

18. A motor vehicle auxiliary electric heating device comprising:

a plurality of separately controllable heating elements which are connected to one another so as to form a heating block, wherein each of said heating elements is adapted to be controlled separately to heat a particular portion of a total air flow to be heated, the remaining portion of the total air flow being heated only by the remaining heating elements; and

a control device for controlling the heating elements, the heating power for each of said heating elements being separately adjustable,

wherein the control device is configured such that, when control of the individual heating elements is effected, an allocation of the respective separately adjustable heating powers to the individual heating elements is changeable at predetermined time intervals.

19. An electric heating device according to claim 18, wherein the change of allocation represents a permutation or a rotation of the allocations of the respective separately adjusted heating powers to the individual heating elements.

20. An electric heating device according to claim 18, wherein the control device is configured to control at least one of the heating elements through switching over between a maximum heating power and zero power.

21. An electric heating device according to claim 18, wherein the control device is configured to control at least one of the heating elements via a substantially continuously adjustable heating power.

22. An electric heating device according to claim 18, wherein the control device is configured to control one of the heating elements via a continuously adjustable heating power and all the other heating elements through switching over between a maximum heating power and zero power.

23. An electric heating device according to claim 21, wherein the control device is configured to control the at least one heating element, whose heating power is continuously adjustable, via a pulse width modulation.

24. An electric heating device according to claim 22, wherein the control device is configured to control the one heating element, whose heating power is continuously adjustable, via a pulse width modulation.

25. An electric heating device according to claim 24, wherein the predetermined time intervals represent an integer multiple of a period of the pulse width modulation.

26. An electric heating device according to claim 25, wherein the heating device comprises a total of four separately controllable heating elements and the predetermined time intervals are equal to eight times the period of the pulse width modulation.

27. A method of controlling a motor vehicle auxiliary electric heating device, the heating device comprising a plurality of separately controllable heating elements which are interconnected so as to form a heating block, the method comprising:

adjusting the heating power for each of said heating elements separately so that each of said heating elements heat only a portion of the total air flow to be heated, the remainder of the total air flow being heated by the remaining heating elements, and

changing the allocation of the respective separately adjusted heating powers to the individual heating elements at predetermined time intervals.

28. A method according to claim 27, wherein the change of allocation represents a permutation or a rotation of the allocations of the respective separately adjusted heating powers to the individual heating elements.

29. A method according to claim 27, further comprising controlling one of the heating elements through switching over between the maximum heating power and zero power.

30. A method according to claim 27, further comprising controlling at least one of the heating elements via operation of a substantially continuously adjustable heating power.

31. A method according to claim 27, further comprising controlling one of the heating elements via a continuously adjustable heating power and controlling all the other heating elements through switching over between a maximum heating power and zero power.

32. A method according to claim 30, wherein the step of controlling the at least one heating element comprises continuously adjusting the heating power of the at least one heating element via a pulse width modulation.

33. A method according to claim 31, wherein the step of controlling the one heating element comprises continuously adjusting the heating power of the one heating element via a pulse width modulation.

34. A method according to claim 33, wherein the predetermined time intervals represent an integer multiple of a period of the pulse width modulation.