In concept, a turbocharger is a really simple device with only a single moving part, turning exhaust energy into compressed air to feed back into the engine. In practice, though, there is no limit to how arbitrarily complex they’ve become. Without adding any extra parts, you can build turbine wheels from exotic materials designed to withstand absurd temperatures, and you can cut compressor wheels from billet instead of casting them, to allow higher shaft RPM without failure.
Take it a step farther, and you can water-cool the center section and replace the oil-fed plain bearings that support the shaft with ball-bearing units to allow the turbo to spool quicker. You’re still just taking baby steps, though – as far back as 1989, a variable-nozzle turbo (VNT) was available in a passenger car application, and today, the MGU-H component of Formula 1 ERS (Energy Recovery Systems) technology utilizes stored electrical energy to both eliminate turbo lag and control boost pressure in place of a wastegate.
All these advances in turbo technology have one thing in common, though – they all rely on exhaust pressure to actually spin the turbine, and are therefore limited to the amount of energy it’s possible to extract from expanding gasses. Sure, you could drive a centrifugal compressor wheel via a gearbox connected to the crankshaft, but then you’re robbing power that would otherwise be delivered to the tires, and adding complexity in the form of some sort of belt or gear drive.
Hybrid Turbos, a UK-based company with a long history of turbocharging expertise, has finally found a way to take turbo technology to the next level, though. As you can see in this video, with their new system there is no backpressure, no exhaust heat, no complicated drive mechanism – just clean, environmentally-friendly power.