Whats the point of a electric-hybrid stroke 4 stroke ICE ?

Well for starters I think its a not so great idea, but nonetheless one that merits some form of exploration, as it tries to improve the efficiency of systems that have a high impact on the world.

Image created with ChatGPT.

As a concept architecture this engine is a 4-stroke ICE type that isn’t scalable, so its just 1 cylinder connected to an electrical machine that acts like a motor and a generator.

The feature the makes this system stand apart from others is that during non power strokes such as intake,compression and exhaust the electrical machine can can act like a motor. And during the power stroke excess mechanical energy can be harvested as the electrical machine acts like a generator. This means that the engine cycle can be actively shaped rather than it being a passive phenomenon.

It is not clear to me at this stage whether there is performance benefit from doing this but its definitely another way of doing it, one that might lead to an overall thermal efficiency gain. A major hurdle is the round trip of efficiency of storing energy in a battery and then reverting it back to kinetic energy during the aforementioned selected stroke or strokes.

Albeit some of the benefits of such a system may include

• Having a smaller flywheel, a device that stores momentum currently in order drive the cylinder during non power strokes. Current range extenders haven’t integrated their generators and ICE to this extent so they still carry a flywheel that I believe is bigger than required.
• Compressing or expanding the air to a greater extent and therefore producing more power or better fuel economy.
• Improved emissions control, through control of shape of the stroke.

It is definitely a doable design but most likely not a commercially viable solution. It is a good exercise to understand that there are likely benefits in taking active control over something that is passive.