Heating and method for controlling heating of a functional unit on a motor vehicle

• US 6,917,019 B2
• Filed: 04/16/2002
• Issued: 07/12/2005
• Est. Priority Date: 04/25/2001
• Status: Expired due to Fees

• Current Assignee: Brose Fahrzeugteile GmbH & Company KG Coburg
• Original Assignee: Brose Fahrzeugteile GmbH & Company KG Coburg
• Inventors: Richter, Stefan
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US10/473,660
• Publication Number:
  US 20040094529A1
• Time in Patent Office: 1,183 Days
• Field of Search: 219/505, 219/504, 219/494, 219/497, 219202-206, 219/490, 219/491
• US Class Current: 219/505
• CPC Class Codes: H05B 1/0236 for vehicles
• CPC Class Codes: H05B 2203/035 Electrical circuits used in resistive heating apparatus
• CPC Class Codes: H05B 3/84 Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields

Abstract

Heating of a functional unit is started by a control device. An actual temperature or a parameter dependent on the actual temperature is monitored during, and optionally before and after the actual heating of the functional unit. A characteristic feature of the time course of the actual temperature or of the parameters dependent on the heating temperature, which determines the phase transition of water, serves for the evaluation and control of the heating. Analysis of the characteristic features is used to control the heating power of the heating elements. Threshold values and further factors such as proportionality factors for the controller, for example, are determined depending upon significant characteristics. The threshold values and factors are also particularly used for a subsequent starting of the heating using the corresponding analysis and control.

Claims

1. A method for controlling heating of a heatable component on a motor vehicle, the heatable component having at least one heating element whose heating power is electrically controlled, comprising:

starting heating of the function unit;

determining at least one of an actual temperature of the function unit and a parameter dependent on the actual temperature;

determining a temporal course of at least one of the actual temperature and the parameter dependent on the actual temperature;

evaluating at least one characteristic feature of the temporal course to determine a phase transition of water; and

controlling the heating power of the at least one heating element based on the evaluation of the at least one characteristic feature.

2. The method of claim 1, wherein the step of determining the actual temperature or the parameter dependent on the actual temperature occurs before, after, or before and after a heating period.

3. The method of claim 1, further comprising the steps of determining the phase transition of water prior to a heating period;

and

at least one of automatically starting the heating and raising the heating power based on the determined phase transition.

4. The method of claim 1, wherein the step of determining the actual temperature or the parameter dependent on the actual temperature occurs only during a heating period.

5. The method of claim 1, wherein different falling and/or rising speeds of the actual temperature or of the parameter dependent on the actual temperature, caused by phase transition of water are evaluated as characteristic features.

6. The method of claim 1, wherein a minimum of the time change of the actual temperature or of the parameter dependent on the actual temperature, caused by a phase transition of water, is determined as a characteristic feature.

7. The method of claim 1, wherein the at least one heating element through which a heating current flows for heating is a temperature-dependent heating resistance, wherein as the parameter dependent on the actual temperature is determined the temperature-dependent heating resistance or a measured value dependent on the temperature-dependent heating resistance, and the heating power is controlled with reference to the determined temperature-dependent heating resistance or the measured value.

8. The method of claim 7, further comprising evaluating a time change of the heating resistance or the measured value dependent on the heating resistance in order to additionally control the heating;

determining a value of the heating resistance or the measured value dependent on the heating resistance for a minimum of the time change; and

comparing the heating resistance with the value or the measured value for subsequent evaluations.

9. A method of claim 1, further comprising storing the value of the actual temperature or the parameter dependent on the actual temperature.

10. The method of claim 8 or 9, wherein the heating is controlled based on the value and a temperature coefficient of the heating resistance by determining at least one threshold value based on at least one of the value of the heating resistance and the measured value dependent on the heating resistance;

comparing the heating resistance or the measured value by a comparator with the at least one threshold value; and

controlling the heating based on comparison.

11. The method of claim 8, further comprising

comparing, by a window comparator, the values of the heating resistance or the measured value dependent on the heating resistance with an upper threshold value and a lower threshold value;

switching off the heating if the value of the heating resistance or the measured value dependent on the heating resistance exceeds the upper threshold value; and

switching on the heating if the value of the heating resistance or the measured value dependent on the heating resistance falls below the lower threshold value.

12. The method of claim 1, further comprising switching the heating current on in intervals;

and regulating the heating current by means of a pulse width modulation.

13. The method of claim 7, further comprising determining the temperature-dependent heating resistance or the measured value based on at least one of the heating current and a heating voltage by means of at least one of flowing, at least temporarily, a constant current independent of the temperature through the heating resistance switching the heating resistance, at least temporarily, as an element of a measuring bridge, and determining the heating resistance by means of the measuring bridge, and switching the heating resistance, at least temporarily, as an element of a resonant circuit, and determining the heating resistance by means of the frequency of the resonant circuit.

14. A method of claim 1, further comprising using a temperature sensor of the vehicle to measure an air temperature independent of the heating;

and

controlling the heating based on the measured air temperature.

19. The method of claim 1, wherein the function unit is at least one of a side mirror, a lock and a window pane.

20. The method of claim 9, wherein a value of the heating resistance or a measured value of a parameter dependent on the heating resistance for a specific phase transition of water is stored.

15. A heating system comprising a heatable component on a motor vehicle, with at least one heating element whose heating power is electrically controlled, and a control device configured to start heating of the function unit;

determine at least one of an actual temperature of the function unit and a parameter dependent on the actual temperature;

determine a temporal course of at least one the actual temperature and the parameter dependent on the actual temperature;

evaluate the at least one characteristic feature of the temporal course to determine a phase transition of water; and

control the heating power of the at least one heating element based on the evaluation of the at least one characteristic feature.

16. The heating system of claim 15, wherein the at least one heating element is a temperature-resistant heating resistance through which a heating current flows for heating and the control device further comprises a measuring unit and a control element, wherein the measuring unit is connected to the temperature-dependent heating resistance for measuring at least one of the temperature-dependent heating resistance and a value dependent on the temperature-dependent heating resistance, and the control element of the control device is connected to the heating resistance.

17. The heating system of claim 15 or 16, wherein, in order to determine a time change of resistance values of the heating resistance, the heating system further comprises:

at least one of a timer and an impulse transmitter connected to the control device, and

an analog-digital converter of the measuring unit comprising an analog input connected to the heating resistance, wherein the at least one of a timer and impulse transmitter enables clocking of digital elements of the control device,

and wherein the time change of at least one of the heating resistance and the heating temperature is determined from the differences between two successive time-based measured values.

18. The heating system of claim 15, wherein the control device further comprises at least one of

a memory for storing a value of the actual temperature or a parameter for a characteristic of the time path of the actual temperature;

and

a constant voltage source, for determining the heating resistance, connected, at least temporarily, to the heating resistance and an integrated switch circuit with a computer and a power semi conductor controllable by the computer in smart-power technology.

21. The heating system of claim 15, wherein the function unit is at least one of a side mirror, a lock and a window pane.