Porsche’s Six-Stroke Engine – A Joke or What?

No joke, the patented engine design features a special crankshaft that adds more power and compression strokes to the cycle. It is also more efficient because of a cleaner burn, at the expense of complexity.

Porsche new six-stroke internal combustion engine design differs from the normal four-stroke example that has intake, compression, power, and exhaust strokes. The Porsche gurus add another compression and power stroke to this process. Documents filed with the US Patent and Trademark Office outline “six individual strokes that can be divided into two three-stroke sequences.” The first sequence involves intake-compression-power strokes, and it’s followed by compression-power-exhaust strokes.

A special crankshaft is needed spinning on a ring with two concentric circles. This alternates the centre point of rotation, effectively lowering the piston’s travel at both extremes, enabling the added strokes. 

The advantage of this design is that it has the potential to generate more power with better efficiency. In a typical engine, only one stroke in four makes power. This changes the formula to one stroke in three, and it also burns up the mixture more completely. Whether the gains are enough to justify the design and build complexity remains to be seen. Possible advantages are increased thermal efficiency (45-50 per cent) and reduced emissions. However, there’s no information on the engine’s vibration or balance issues or how high it revs.

This patent submission suggests that Porsche is working hard at finding ways to keep combustion engines alive amid the push to electric power.