Rear window heating
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The rear window heating is a common feature of a motor vehicle . It is installed in series in almost all passenger cars and was developed by Heinz Kunert in the early 1960s .
Layout and function
The electric rear window heating can be implemented in (at least) two ways:
- On the one hand, the heating wires can be printed onto the window from the inside, which is a variant that is inexpensive to manufacture. Here the heating cables are mostly red due to the oxide layer and about 1 to 2 mm wide and are perceived by some as annoying. They are also unprotected against damage from pointed or sharp objects in the car. But they can be repaired because they are freely accessible.
- The rear window heating of the "printed conductor paths" variant was developed by Ford Motor Company at the end of the 1960s . It was first installed in series production in Lincoln vehicles in 1974 . It consists of thin, electrical heating cables that are attached to the inside of the rear window. When the rear window heater is switched on, electricity flows through it, causing them to heat up due to the electrical resistance . This avoids icing or fogging caused by shifting the local dew point on the pane. In some vehicles, the heating conductors also serve as an antenna for the radio . Defective areas or interruptions in the heating conductors can cause radio interference when the rear window heating is switched on.
- If a printed heating cable is interrupted, it can be repaired using paint with silver powder ( conductive paint ) suspended in it.
- Another variant of the rear window heating consists in not printing the wires, but inserting them between the two layers of a laminated glass pane. These can be considerably thinner than 1 mm and are therefore less visually disruptive. The disadvantage is the high manufacturing cost and thus the high price of such a disk. A heating wire that is damaged by aging cannot be repaired either, since it lies between two panes. However, the wires are protected from damage by sharp or pointed objects in the interior.
- The rear window heating in the variant "wire between two laminated glass panes" appeared for the first time in January 1964 as code 248 in the surcharge lists of Daimler-Benz AG . On Oldtimertreffen you get occasionally to see such a heated rear window today.
Both variants are supplied with power from the vehicle electrical system . An average rear window heater has an output of about 150 W . Continuous operation of the heated rear window is associated with an additional fuel consumption of around 0.13 liters per 100 kilometers, as the alternator has to generate more power. For this reason, many rear window heaters have a time-controlled automatic switch-off.
Windshield heating
Front windows can also be heated. As a rule, panes with very thin embedded wires are used in order to impair the view as little as possible. Ford or Renault im Twizy , for example, offer this additional equipment . In the military sector z. B. the MARS rocket launcher vehicle via heated front windows. A windscreen heater can also be installed in a latest-generation Unimog .
Specialist literature
- Rudolf Hüppen, Dieter Korp: Car electrics all types. 7th edition, Motorbuchverlag, Stuttgart 1972, ISBN 3-87943-059-4
Individual evidence
- ↑ Erich Kupfer: VdM colleague Dr. Heinz Kunert died. ( Memento of the original from October 29, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Report to the Association of Motor Journalists
- ↑ Rear window heating interferes with radio reception
- ↑ List of the optional equipment codes from Mercedes ( Memento of the original from August 15, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ LEIFI : Increased fuel consumption due to switching on the rear window heating
