oggenc -q 6 blah.wav
you'll get blah.ogg which is not really 192 kbps, but in general most files will be approximatelly 192 kbps. If blah.wav is pure digital silence for example, the bitrate would be very low, but this does not mean blah.ogg is of poor quality, just that blah.ogg can be very easily and effectively compressed with vorbis.
If you really want average bitrate 192 kbps, look at "man oggenc" but recommended and in most cases better is to use the -q (quality setting).
and whats the best .ogg bitrate to NOT lose any quality?
With ogg vorbis or mp3 you'll always lose something. Not that it usually matters, you'll probably not be able to hear the difference. If you want lossless, get flac or some other lossless codec ... and another huge disk
Seriously, if you want high quality, choose -q6, everything above is a waste of disk space. BTW, the default is -q3 and is still very good.