Just a few days ago, news hit the Internet that Porsche has patented a revolutionary new six-stroke engine that they claim has the power advantages of a two-stroke engine, but the durability and emissions of a four-stroke engine. As you probably know, the traditional four-stroke engines that power virtually all combustion cars, trucks, and motorcycles on the road today have intake, compression, combustion, and exhaust. Porsche's new design adds one more combustion stroke and one more compression stroke to the mix, and this is how the new engine works: intake, compression, combustion, compression, combustion, and exhaust. This is based on 100% existing technology: gears, connecting rods, crankshaft, piston. Even the ports, known as scavenging ports, are old. By the way, this same arrangement with ports on one side and valves on the other is known as uniform flow scavenging, because the flow goes in a uniform direction through the cylinder, and this is very common in two-stroke diesel engines in ships and locomotives. Six-stroke engines also don’t pose any serious problems for the camshafts. Instead of rotating at half the speed of the crankshaft, the camshafts will now rotate at one-third the speed of the crankshaft, so we just need a slightly larger cam gear and we also need an extra lobe in the exhaust and that’s it, nothing complex. So, there are really no novel mechanics in this, which means that you don’t need huge investments in research and development to bring it to market. It produces more power than a traditional four-stroke engine. If we look at the first 720 degrees of rotation, we can see that we only have one combustion event, just like a traditional four-stroke engine. But if we look at the next 360 degrees, we will see another combustion event that starts at 720 degrees of rotation. This doesn’t happen in the traditional four-stroke engine until we reach 1080 degrees of rotation. So if we look at, say, 7,200 degrees of rotation, the traditional four-stroke engine will perform 10 combustion events. The six-stroke engine will perform 13.34 combustion events. That's 33.4% more power than a traditional four-stroke engine. Now, it's definitely not in two-stroke territory because a two-stroke engine will perform 20 combustion events in 7,200 degrees of rotation and that's 20 equal and proper combustion events. Remember, in a six-stroke engine, every other combustion event is a mixture of exhaust gases, air and fuel, which means we're probably not looking at a 33.4% increase in power, but probably something closer to 25%. But 25% more power with existing technology and the emissions cleanup and durability of a traditional four-stroke engine is still a very significant improvement and a very smart and rational way to achieve more power. Another thing this makes possible is to use very high boost pressure and still be relatively emissions friendly. To use 3 bar boost pressure, which is 45 psi, you need to use a very rich mixture. It makes incredible power, but you're also sending some unburned fuel into the atmosphere, which means poor quality emissions. But in a six-stroke engine we wouldn't send all that unburned fuel out. We'd send only some of it out and the rest would be burned during the next combustion stroke. So potentially huge power and government approval. But why would Porsche patent this now when sales of new combustion vehicles will be banned from 2035 in the EU and I think in some other parts of the world? Well, here's the thing: the EU is not completely banning sales of new combustion vehicles from 2035. On March 25, 2023, the EU reached a deal with Germany in which it was agreed that sales and registration of new internal combustion engine vehicles will be allowed after 2035, provided that those vehicles run only on carbon-neutral fuels. Will we see this engine in the future? Well, if e-fuel production really does ramp up, I think it's likely that Porsche will give the green light to some kind of project. Will e-fuel be expensive? Probably. But I doubt that will be a major issue for Porsche buyers. #d4a #d4aespanol #porsche #sixstroke 00:00 How it works 14:34 Disadvantages 19:01 Why now?