Variable Piston Stroke and Variable Compression in Internal Combustion Engines

On January 7, 2026, we filed a patent application with the U.S. Patent and Trademark Office for a mechanical adjustment mechanism designed to make the piston stroke and compression ratio of an internal combustion engine adjustable.

This device is designed to adapt to the specific needs of the vehicle and the driving situation in order to increase the engine’s efficiency.

As part of this development, the compression ratio is adjusted according to engine speed—either increased or decreased, depending on what is desired.

This will make it possible to reliably adjust the piston stroke of the same engine during operation from, for exaWhen this invention is published by the Patent Office, it will be disclosed here along with the sketches; below is a preview of the result of the adjustmentmple, 50 mm to 100 mm, and the compression ratio from, for example, 7:1 to 14:1.

Depending on design requirements, the system can be switched from a long piston stroke with a low compression ratio to a short piston stroke with a high compression ratio, or conversely, from a long piston stroke with a high compression ratio to a short piston stroke with a low compression ratio.

It is also possible to adjust only the piston stroke—that is, the displacement and maximum RPM.

It would also be possible to change only the compression ratio, from high to low.

All of this can be done while the engine is running.

Figs. 2a and 2b show the mechanical adjustment with a short piston stroke and high piston compression without the adjustment mechanism.