My Idea is for an air-powered hybrid transportation drivetrain utilizing a small diesel powered gas-turbine engine to compress air and provide range-extension. the gas turbine should be sized to provide a real-time air supply to a reciprocating piston air engine, actuated by air-powered rotary valves.

When vehicle idles down, stops or brakes, the air engine serves as a regenerative compressor, pumping air back to the compressed air storage tank to store energy until the vehicle uses it for acceleration.

Stored compressed air can be tapped to power pneumatic sub-systems in the vehicle, eliminating belts, pulleys, and electric motors. These would use small rotary pneumatic motors (as are used in air-tools).

It can also power a pneumatic starter to spin-up the gas-turbine engine, which itself is fueled by widely available Diesel fuel. A depleted compressed air-storage tank can be recharged at home base with a basic stationary air-compressor. a standard air-tap can provide compressed air for flat tires, recreational use, etc.

Gas-turbine engines have not been successful in ground transportation because they do not respond well to throttling and extreme RPM changes. The high operating RPM's make a direct gear reduction to wheel RPM difficult and problematic. Gas-turbines have low torque at lower RPMs, making acceleration feel sluggish until they spin-up to peak operating RPM, which is over 20,000 RPM. The result is inadequate acceleration and inefficient start/stop operation resulting in poor fuel economy.

By de-coupling the gas-turbine from the torque-producing prime mover with an air storage system, the the gas-turbine can be sized for the indended purpose, and allowed to operate efficiently with a steady, optimal RPM. It can continuously pump air into the compressed air storage tank when idled down to recover lost energy. The air-powered piston-block, or reverse air-compressor, provides the torque needed for acceleration and passing. It can return compressed air to the air-tank under engine-braking, actuated by variable valve timing.

The system is designed to be analogous to a gas/ electric hybrid system, with air replacing electricity and batteries for transfer of energy and energy storage. The gas-turbine engine has fewer moving parts than an equivalent ICE engine, and the piston air-engine is stripped of an ignition, fuel, and a cooling system.

The air storage capacity will be limited by the packaging of the vehicle, but the system is scalable and may be most applicable to trucks and semis which contain a large amount of wasted space.

Frank DiMino 6-30-2025