AutoGuide recently discovered a patent filing from the Korean car maker for a "system and method for motor-assisted non-uniform displacement engine control".
In a nutshell, the hypothetical engine would have two types of cylinders, each with a different displacement. For example, a four-cylinder would have two 500cc cylinders, and two 450cc cylinders.
Connected to the engine is an electric motor, which would be used to balance torque output from the unevenly sized cylinders. It would also help to minimise the extra noise and vibration generated by an engine with non-uniform cylinder displacements.
A drivetrain control unit would be able to operate the new type of engine in at least three different modes.
According to Hyundai, a traditional engine with cylinders of the same size has "a margin for operation point control [that] is insufficient due to the fixed displacement thereof". The automaker also says that current production engines spend too much mechanical energy in order to idle in a stable way.
Hyundai made the original filing on December 2, and the application was published on March 22, 2017.
It's not known how far along Hyundai is with development of this new engine type, nor is it known if the company intends to proceed with such a design for production. The company has yet to display a concept car with this style of engine.