Method and arrangement for de-icing a transparent window using an electric heating device
An arrangement and a method for de-icing a transparent window, in particular a vehicle windshield, with an electric heating device, are described. The method has the following steps: Step A): Measuring a window temperature before an initial application of a heating voltage; Step B): Measuring the window temperature after a beginning of a heating period; and Step C): Applying a heating voltage of more than 100 volts to a heating device over a heating period of a maximum of 2 minutes, in particular a maximum of 90 seconds, and repeating step B).
1. A method for de-icing a transparent window with an electric heating device, the method comprising, on a basis of a manual or automatically initiated de-icing process, the following steps:
Step A): measuring a window temperature before an initial application of a first heating voltage of more than 100 volts, wherein
i) the method is terminated when the window temperature exceeds a lower temperature threshold value,
ii) or the first heating voltage of more than 100 volts is applied to the heating device over a first heating period of a maximum of 2 minutes, when the window temperature is equal to or less than the lower temperature threshold value, and wherein the first heating voltage and the first heating period are selected such that a first heating power of at least 2 kilowatts (kW) per square meter (m 2 ) of window area is generated, and step B) is executed;
Step B): measuring the window temperature after a beginning of the first heating period, wherein a de-icing process
iii) is terminated when the window temperature reaches an upper temperature threshold value,
iv) or step C) is carried out when the window temperature is lower than the upper temperature threshold value; and
Step C): applying a second heating voltage of more than 100 volts to the heating device over a second heating period of a maximum of 2 minutes with the second heating voltage and the second heating period selected such that a second heating power of at least 2 kilowatts (kW) per square meter (m 2 ) of window area is generated, and repeating step B);
wherein in step A), duration of the first heating period is selected as a function of the window temperature measured in step A), with a shorter first heating period selected in case of a higher window temperature and a longer first heating period selected in case of a lower window temperature; and
wherein in step C) duration of the second heating period is selected as a function of the window temperature measured in step B), with a shorter second heating period selected in case of a higher window temperature and a longer second heating period selected in case of a lower window temperature.
2. The method according to claim 1 , wherein the transparent window is heated during a plurality of the first heating periods.
3. The method according to claim 1 , wherein the first heating period in step A) and the second heating period in step C) have equal duration.
4. The method according to claim 1 , wherein in step A), a quantity of the first heating voltage is selected as a function of the window temperature measured in step A), with a lower first heating voltage selected in case of a higher window temperature and a higher second heating voltage selected in case of a lower window temperature.
5. The method according to claim 1 , wherein in step C) a quantity of the second heating voltage is selected as a function of the window temperature measured in step B), with a lower second heating voltage selected in case of a higher window temperature and a higher second heating voltage selected in case of a lower window temperature.
6. The method according to claim 1 , wherein the first heating voltage and first heating period in step A) and the second heating voltage and the second heating period in step C) are equal.
7. The method according to claim 1 , wherein in step B) the window temperature is measured immediately after expiration of the first heating period.
8. The method according to claim 1 , wherein the lower temperature threshold value is 0° C.
9. The method according to claim 1 , wherein the upper temperature threshold value is in a range from 30° C. to 80° C.
10. The method according to claim 9 , wherein the upper temperature threshold value is 70° C.
11. The method according to claim 1 , wherein the first heating power of Step A is at least 3 kilowatts (kW) per square meter (m 2 ) of window area.
12. The method according to claim 1 , wherein the second heating period of Step C is a maximum of 90 seconds.
13. The method according to claim 1 , wherein the second heating power of Step C is at least 3 kilowatts (kW) per square meter (m 2 ) of window area.
14. The method according to claim 1 , wherein the transparent window comprises a vehicle-windshield, and the electric heating device comprises a heating layer.
15. The method according to claim 1 , wherein the upper temperature threshold value is in a range from 50° C. to 70° C.