It looks like the design of a sliding vane pump.
Thats exactly what I posted a stock picture of.
I’m still trying to figure out how djf’s thing works!
Also there have been motors of that type around for eons. The ones I've seen are pneumatic.
Why not just go back to steam powered cars. I rode in a coal fired, steam powered taxi in Sasebo, Japan in the early 1950’s. We have lots of coal. If we don’t get our oil supply problems worked out we may have to revisit that technology.
I say that in a joking way but, if we continue to slide toward third world status, we will have to use an energy source that is relatively inexpensive and plentiful. Coal!