Abstract: In a shared process control system for a power train of a hybrid electric vehicle operating responsive to operation of an accelerator pedal and a brake pedal and including a gas turbine powering a first motor-generator, a flywheel powering a second motor-generator, and a traction third motor-generator operatively coupled for selectively driving and being driven by vehicle wheels, each of the first, the second and the third motor-generators being commonly connected to a high voltage bus via respective rectifier-inverters controlled by a single controller, the control system is operated by a method including steps for operating of accelerator pedal to produce a substantially instantaneous increase in output torque with an increase in load on the bus by the traction motor to thereby produce a voltage drop, initiating increased power output from the flywheel motor-generator in response to the voltage drop to hold up bus voltage, thereby decreasing flywheel shaft speed, and subsequently producing a proportional in