I don't know what fuels it takes, but the "optimized for a single RPM and torque to spin a dynamo" is pretty much describing Mazda's MX-30 R-EV which does this

I don't know what fuels it takes, but the "optimized for a single RPM and torque to spin a dynamo" is pretty much describing Mazda's MX-30 R-EV which does this with a rotary engine. https://www.autocar.co.uk/car-review/mazda/mx-30-r-ev https://www.autocar.co.uk/car-review/mazda/mx-30-r-ev Won't be coming to the US though, and the EV version is dropped here as well. Now that they have PHEVs in the CX-90 and upcoming CX-70. Previously the MX-30 was available in California as a compliance car.