Honda seems to be working on a new engine design featuring a variable piston stroke.

Discovered by AutoGuide in Japan’s patent office database, the diagrams show what could very well end up being a next-generation engine fitted with pistons of different heights. By implementing variable piston stroke technology combined with cylinder deactivation, this would allow Honda’s engineers to develop an engine with different displacements. 

At least in theory, an engine with four cylinders could have as much as 15 different displacements based on the differing height of each of the four pistons and depending on how many cylinders are actively firing. This would allow Honda to create a very versatile engine that would be offered with different displacements and power tunes to suit a broader array of models. Such an engine would pose far better flexibility compared to a conventional 2.0-liter Honda engine which has four 500-cc cylinders, therefore offering only four displacements: 500cc, 1000cc, 1500cc, and 2000cc.

Developing an engine that could be offered in multiple displacements by varying the height of the pistons would bring significant savings in terms of R&D, allowing Honda to adapt the engine to various applications. The patent shows how the variable piston stroke technology could be adapted for inline two-, three-, and four-cylinder engines, thus opening up new possibilities for next-gen engines that could power tomorrow’s Hondas.


Gallery: Honda patents engine with different sized pistons