A pneumatic-internal combustion (IC) engine based power management system with improved energy efficiency for automobile application. More particularly, the pneumatic IC engine based power management system comprises a compressor, a pressure vessel, a pneumatic motor and related control mechanisms to provide energy on demand and reduce environmental pollution. The compressor is driven by the IC engine during low power demand by the vehicle. The lightweight pressure vessel wrapped with high strength metal wire and/or fibers provide impact resistance adequate to store compressed air at rated pressure. For low/no load condition of engine or compressor, the IC engine will shut off rather than idling to save fuel. The stored compressed air drives the air motor that powers the vehicle's initial motion and then starts the IC engine to provide continuous power. A controller monitors the power demand and actuates different system components accordingly through sensors. The system also supports accessories such as air conditioning, heater etc. and a wheel-rim system for inflation maintenance and easy change over of tires.