I typed " solar car ventilator " into google and got lots of them.
This one gets my vote for best translation to english... (-:

http://www.alibaba.com/trade/offer/detail/10988892.html

>I cannot find it with a cursory google search, but there is a company
>that manufactures a solar-powered ventilation fan that goes in the
>window opening.  It mounts between the window glass and the top of the
>door opening and is held in place by the glass.  Maybe someone else has
>seen these.
>
>Mike Snow