Chalk this one up to wild. General Motors has filed—and been approved—for a patent detailing a super high-compression, turbocharged and supercharged hybrid powertrain. Immediately, we think this kind of high-performance engine could point to a C8 Corvette Hybrid, potentially the rumored Corvette E-Ray.
AutoGuide reported on the patent this Wednesday and detailed what exactly the powertrain is comprised of. Foremost, the powertrain is made up of a high-compression internal-combustion engine, low-flow supercharger and a high-flow turbocharger. The patent describes that the powertrain would connect one or more electric motors or generators. The images do not depict the greener parts of the powertrain.
The patent also describes new twin-charging methods. The supercharger could be driven by a crankshaft or electric motor, while a continuously variable transmission could control the supercharger’s RPM separate from engine RPM. After 3,000 RPM, the turbocharger would spool up and provide power. The system could work in a sequential or tandem fashion and the application could work to provide greater performance or fuel economy.
Most typical engines run a 10.5:1 compression to starve off pre-detonation, but the patent states this engine would deliver ratios of 11 to 16:1. Those are, quite frankly, insane figures. To meet federal requirements to be street legal, GM would employ an extreme variation of the Atkinson-cycle, per the report. A late intake valve would close to let some of the air-fuel mixture to escape and avoid pre-detonation. GM’s patent goes on to describe two different methods to generate peak lift—variations from other Atkinson cycle applications.
The first is cam-lobe profiling with a variable-ratio rocker arm placed between the valve stem and the cam lobe. The second is an electronic solution: an electro-hydraulic actuator that could effectively replace a traditional camshaft.
There are so many possibilities surrounding this concept. Even if it arrives as a high-performance powertrain first, it could also serve as a basis for a variable-compression powertrain in the future, too. We won’t know what becomes of this powertrain likely for some time, but we do know one thing: GM powertrain engineers have been mighty busy.