Porsche obtains a patent for a revolutionary six-stroke engine – Executive Summary

Who said combustion engines are in decline?

Porsche has patented a new type of engine in the United States. Will it be the complement it needs to the renewable e-fuels it is producing experimentally in South America?

Many car manufacturers have given up on developing combustion engines, but the premium German brand recently received approval for the patent they filed in the US at the beginning of this year: So, instead of starting from a blank slate – and casting doubt on the potential validity of their new concept, They chose the traditional four-stroke engine, to which they added two additional strokes.

Almost all cars currently on sale with combustion engines have four-stroke engines: intake, compression, combustion and exhaust. The intake stage is what allows fuel and air to enter the cylinder, while in the case of compression, the piston takes this mixture to the top of the cylinder, which then causes combustion and exhaust ignition, as a final stage, which is when the remaining gas is expelled from the cylinder.

Second combustion

The two new strokes are interspersed before the exhaust gases leave the engine, and before that the burned gases are compressed again so that they undergo a second explosion and thus their combustion is completed – then after these two new strokes the combustion gases exit. They were released.

Documentation provided by Porsche specifically describes that the six individual strokes can be split into two three-stroke sequences, with additional steps occurring between the conventional combustion stroke and the exhaust stroke. In other words, the first sequence will be intake-compression-combustion, while the second sequence will be compression-combustion-exhaust.

The goal is to extract maximum energy and power from twice-burned fuel – in addition, complete combustion allows the gases to combine and release fewer polluting gases.

If it sounds easy in theory, Porsche has also achieved a relatively simple physical implementation of the engine. To the crankshaft assembly that connects the classic piston, he added an eccentric gear that forces the piston to travel three different distances back and forth in each working cycle, making up these six strokes.

As a result, it is also a variable compression ratio engine, which can be changed via an auxiliary transmission, as can also be found in Nissan e-Power engines.

The Porsche engine has a unique feature: it also incorporates the exhaust ports in the cylinder characteristic of two-stroke engines, thus achieving high power. A variable compression ratio can reduce consumption: by burning the mixture twice, a lower level of polluting emissions will be achieved.

From 2035 onwards, only cars with zero polluting emissions or with combustion engines with net-zero CO2 emissions will be sold in the EU. Will this be the e-fuel engine that Porsche is considering in South America to meet this requirement? Everything points to yes, otherwise there would be no need to patent, unless combustion engines are expected to have a long run.

It is not known which future Porsche model will be able to integrate this technology, nor is it certain that the German brand will put it into production, but we can certainly see significant efforts to keep the combustion engine in place for a long time.