A hybrid vehicle system having first and second internal combustion engines, first and second flywheels respectively coupled to the first and second internal combustion engines, a plurality of motorized wheels electrically interconnected to first and second flywheels, and a controller connected to the internal combustion engines and to the flywheels and to the plurality of motorized wheels for transferring energy therebetween. Each of the flywheels has permanent magnets affixed to a side of a housing thereof. Each of the flywheels is vacuum sealed within anon-ferrous housing.