Very interesting discussion IMO, thanks for sharing it.
If you are using PM DC torque motor, the braking torque problem is fairly simple. Since the motor is now acting like a generator, controlling the electrical load on the "generator" will control its braking torque. Polyphase AC motor braking torque control is a much more difficult problem.
Sorry if I missed it, but I don't think I've seen mention of where the energy recovered under braking goes. In a modern diesel-electric locomotive the generated power is dissipated as heat in the braking grid resistors mounted atop the car body. In a contemporary EV the generated power is used to recharge the battery.
Tim
Hi Tim...no we haven't discussed where the energy goes when power to the wheel motors is cut and they effectively become generators feeding electromotive force back into the circuit that drives them under IC power. Up front I'm not an engineer...mechanical, electrical, or otherwise. What I'm commenting on here is my understanding of how this circuit would work under the conditions described. I may be half wrong or entirely wrong but I don't think so unless or until shown otherwise.
If the electrical circuit between the generators and motors is broken or disconnected there will be voltage but no current flow so the gen/motor mechanism will free wheel to some theoretical maximum voltage the circuitry can withstand. All well and good for idling or coasting but contributes nothing to braking. When the circuit is closed however the gen/motors switch roles and electromotive force or EMF generated by the wheel motors is effectively driving the IC gen/motor connection. The degree of force the IC gen/motors sees is determined by voltage the controllers are programmed to power the now reversed circuitry.
In my vision of the design, when power to the IC engines is cut (throttle off switches off ignition spark and fuel injectors) the 8 rotors and spinning generators become an active flywheel. Reversed polarity EMF from the wheel motors attempts at low voltage to slow rpm of the flywheel and reverse rotation of both the generators and IR rotors. EMF Voltage is progressively increased as IC rotor rpm comes down to the point where the IC gen/rotors actually begin to rotate in the opposite direction and begin ramping up flywheel rpm absorbing braking energy generated by the wheel gen/motor EMF. During the spin down to IC flywheel reversal the aluminum rotor housings and separator plates become heat sinks acting as resistors to dissipate heat build up in the gen units. The oil and coolant pumps all being electric motor driven would continue to run in standard rotation to keep oil and coolants flowing until IC flywheel eventually stops.
In a rotatory engine there are no valves or cams to contend with; reverse rotation is possible where the engine acts as an air pump under compression load dumping compressed air back into the atmosphere through intake ports and turbo housing. When the car comes to a stop the IC flywheel is still spinning and can spool down under is own internal friction load. I'm open to correction or clarification on any of this if someone with better knowledge knows reasons why this wouldn't work. Thanks...Terry