Okay... let me try here:
You have read that motors can be operated by interfacing them with a "mico" processor called "Stepper motor."
Motors are controlled by different methods:
- PWM DC
- DC current modulation
- AC current modulation
- AC voltage modulation
Their shaft positions are reported by feedback devices:
- optical encoder
- sin/cos incremental encoder
- magnetic pole position resolvers
By using a setpoint driven system and comparing that setpoint to feedback device's location (called error) to feed a controller (usually a PID controller), you can maintain reasonable control over the motor.
As for a stepper motor: they are just a special kind of synchronous motor. Nothing really different here, except that they are usually designed for small discrete movements. Stepper motors are often multi-phase internally, but might still be fed from a DC source for simplicity.
Can you control a stepper motor based on feedback using modern drive equipment? Yes, absolutely. There's a good chance that if you have a late model car, the gauges on the dash are actually connected to stepper motors.
Then you mentioned something about "modern day engines."
When I think of an engine, I think of an ICE (internal combustion engine). However, obviously this isn't what you meant since ICEs aren't controlled by magnetic field generation using electric current, they are controlled by explosions in cylinders generating a linear motion that is converted to rotary motion by means of a crankshaft.
So, I have no idea what you meant with that last comment.
As a side note, though... internal combustion engines have been using computers (micoprocessors?) to help control fuel mixture (by means of fuel injection systems) and timing (by means of relative spark advance and retarding systems). Lots of new engines also use variable valve lift accomplished by non-linear camshaft geometry.
Lastly, perhaps you are talking about the electric "engine" in a Prius, or other hybrid cars. This is just an electric motor. There is no electric "engine" to speak off. Rather there is an internal combustion engine and an electric motor on a shared-shaft power delivery system. Is there a computer in a Prius? Definitely!
Now... please... what question did you intend to ask? I can't guess anymore.