The devs teased an dyno in the dev blog a while back in 2016 but they never updated us more on it because they encountered some bugs that they have problems with. May have been put on hold to prioritize other stuff. Link (scroll a bit for more): https://www.beamng.com/threads/micro-blog-s-march-to-december-2016.23153/page-2#post-365074
It was never in a public release. Canceled/put in development limbo due to bugs they couldn't work out
This. Basically they toyed with it. Couldn't get it to work, and scrapped it. It was never in the actual game.