Oh okay, the problem is that the TU9 universities only offer fully-taught-in-English degrees at graduate level.
Actually, studying at RWTH for example at undergraduate level in German without any German language skills is not very difficult, because most of the exercise classes and tutorials are also offered in English - but a B2(?) or TestDAF Level 4 is required for admission.
If you have some German language skills right now, it could be recommendable to take an intensive language course to get to the required level just to have the proficiency in German language for admission.
Otherwise, there is a very interesting program at Universität Duisburg-Essen, the International Studies in Engineering (ISE) program. The first year in the degree program is taught 100% in English, in total it is about 50% English, 50% German. (The required A2 level for this degree is possible with a 2 week intensive language course) http://www.uni-due.de/imperia/md/con...ee_courses.pdf
I know a guy from Canada, who completed this program first, before he started a Master's degree at RWTH. As far as I know, he is at UC Berkeley atm to do a collaborative research project with an institute in Aachen.
If you want to study both in USA and Germany, this may be a possible path for you. Most German universites have mobility programs to the USA
(e.g. RWTH -> UC Berkeley and UC Davis) RWTH International - Mobilitätsprogramme der RWTH Aachen
More interesting links:
Computer Science Computer Science B.Sc. - RWTH AACHEN UNIVERSITY
Computational Engineering Science Computational Engineering Science B.Sc. - RWTH AACHEN UNIVERSITY
Mechanical Engineering (more like General Engineering - you can specialize in Chemical, Aeronautical, Automotive, Simulation, Process ... Engineering after 2 years) Mechanical Engineering B.Sc. - RWTH AACHEN UNIVERSITY
Study in Germany Checklist for foreign students: studieren . de
Scholarship DAAD - Scholarship database