You can freely build on How the Wankel Rotary Engine Works

What this patent covers

The Wankel engine uses a triangular rotor that spins inside an oval-shaped housing. As the rotor turns, it creates three separate combustion chambers that expand and contract. This design allows the engine to perform the four stages of combustion—intake, compression, power, and exhaust—in a continuous, circular motion rather than the up-and-down movement of traditional engines.

What is now free to use

All 0 claims of US 2988008 are in the public domain. Specifically:

The 0 dependent claims add narrowing limitations and are also free.

What is NOT covered

Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.

• Does not cover traditional reciprocating piston engines found in most cars.

• Does not cover electric motors or battery-powered propulsion systems.

• Does not cover gas turbine engines or jet propulsion technology.

Who is building on this today

Mazda remains the primary manufacturer to have successfully commercialized the Wankel engine at scale. Today, startups and niche manufacturers are exploring rotary designs as compact range extenders for electric vehicle battery packs.

Products built on expired version of this technology

How to cite this patent in your documentation

WANKEL AND NSU MOTORENWERKE AG. US Patent 2988008. Rotary piston machines. Granted 1961, expired 1978. Now in the public domain.

Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.

PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.