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Porsche's idea for a six-stroke internal combustion engine

motor1.com

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Re: Porsche's idea for a six-stroke internal combustion engine

#281

Post by vvillena »

01HNNWZ0MV43FF wrote: post #276
markhahn wrote: post #252

I always wonder about premises in cases like this. a pair of compression-power cycles is a nice way to question the usual. has anyone gone through all the features of a conventional engine and asked: what if there's an alternative? for instance, what if we're just interested in range-extension? can we transform the motion created by combustion into electrical power in a clever way? cylinder-solenoid coils? are poppet…

Cylinder solenoids are indeed a thing https://en.m.wikipedia.org/wiki/Free-piston_engine And the Prius uses the Atkinson cycle which is slightly different from the traditional Otto cycle somehow, although I couldn't find a good explanation https://en.m.wikipedia.org/wiki/Atkinson_cycle

According to that Wikipedia article, the modern Atkinson cycle trades time spent creating power in the compression phase for time spent extracting energy during the expansion phase, gaining efficiency at the cost of total power.

Re: Porsche's idea for a six-stroke internal combustion engine

#282

Post by ryukoposting »

kopirgan wrote: post #212

Know nothing about automobile engineering but somehow this feels like WordPerfect releasing a fantastic version for DOS when Windows was already capturing all the market. Btw they did that. Rest is history.

There's another block of folks who look at Tesla like a company who's making great software in 1994, but it only runs on Windows NT.

Yes, EVs are better in a lot of ways, but in 2024 there are severe barriers that make EVs impractical for a lot of people. Throughout most of the world, charging infrastructure just isn't good enough.

Because cities have better charging infra than rural areas, EVs are at their best as commuter cars. Ironically, there was already an alternative to commuter cars that's hypothetically even better than EVs - public transit - and it also suffers due to lack of investment in infrastructure development.

Re: Porsche's idea for a six-stroke internal combustion engine

#283

Post by akira2501 »

outside1234 wrote: post #266

Reading these articles is like when you used to read articles in 2005 about people "innovating" on OS/2. The market has moved to electric (see China) and Porsche would be well served on investing there versus on OS/2 (nee ICE engines).

> The market has moved to electric

It has not.

> (see China)

Understand the impact of subsidies.

> versus on OS/2 (nee ICE engines).

There is no roadmap to an electric plane in your lifetime. ICE engines are going to be here longer than you are.

Re: Porsche's idea for a six-stroke internal combustion engine

#284

Post by kevin_thibedeau »

mpol wrote: post #270
markhahn wrote: post #252

I always wonder about premises in cases like this. a pair of compression-power cycles is a nice way to question the usual. has anyone gone through all the features of a conventional engine and asked: what if there's an alternative? for instance, what if we're just interested in range-extension? can we transform the motion created by combustion into electrical power in a clever way? cylinder-solenoid coils? are poppet…

Since hybrids are now so popular, rethinking how a gasoline engine fits into that picture might be worth it. Question is whether the market will shift again from hybrids to full EV, and if so, when. Designing and building a new engine might cost 5 billion, without a real certainty you will earn it back.

BEVs will never take over in North America. There are too many people spread out or living in places with no hope of charging infrastructure. People are going to balk when they find out they can only charge from a 20A circuit if even that is available.

Re: Porsche's idea for a six-stroke internal combustion engine

#285

Post by Too »

ithkuil wrote: post #259
markhahn wrote: post #252

I always wonder about premises in cases like this. a pair of compression-power cycles is a nice way to question the usual. has anyone gone through all the features of a conventional engine and asked: what if there's an alternative? for instance, what if we're just interested in range-extension? can we transform the motion created by combustion into electrical power in a clever way? cylinder-solenoid coils? are poppet…

Iirc Koenigsegg is using camless valves (using solenoids?)

Freevalve yes.

They’ve got loads of other cool thinking outside of the box solutions. Like the Lightspeed transmission with 7 clutches, providing instant shifting between any gears and ability to slip freely between them.

Re: Porsche's idea for a six-stroke internal combustion engine

#286

Post by quintushoratius »

hnlmorg wrote: post #220
quintushoratius wrote: post #213

Earlier quoted context omitted.

> In my experience the maintenance costs is usually more tyres, suspension, breaks, and other similar things that would equally need to be maintained on EVs. You'll go through tires _slightly_ faster because the cars are heavier. With the exception of some standouts like Tesla's Cybertruck, which reportedly is only getting 6k miles on a set of tires, the wear rate is slightly higher. Low rolling resistance tires are…

You’re drastically overstating the differences between ICE and EV there. But that might be a side effect of American cars vs European cars.

I don't think I'm overstating anything.

My wife and I have owned an EV since 2019. We also still have a couple of ICEs for me and my daughter. I'm not going to throw a car away just because.

I see the cost savings of an EV up close and personal. The only downside has been range for long trips, but 364 days of the year that's not a problem and for the remaining days my ICE does the job. When that car dies, I'll rent one when it's needed.

Re: Porsche's idea for a six-stroke internal combustion engine

#287

Post by 00N8 »

larodi wrote: post #153
pineaux wrote: post #32

Earlier quoted context omitted.

Yeah. It looks pretty cool. There is something satisfying about a complex mechanical mechanism. However, in its current form it is not the future. Combustion engines in general are not going to be the future. Hydrogen is a joke. Not energy dense enough. And expensive to make (energy wise). It also needs a vast network of gas stations.

Who says so? Batteries been available for hundred years yet we keep talking about fusion being the future, and we have fission. Which both drive turbines, which are a thing from the past? No? What is joke and when? To me is a joke that we keep heating water to move magnets to get energy in 2024 with all the quantum entanglement, Johnson teleportation, lasers, etc. engineering magic happening around. And we do what? h…

Compressed hydrogen has low enough density that even at dangerously high pressures it would take up most of the luggage & passenger areas of a car, just to get mediocre range. Liquid hydrogen has better density (roughly 2x), but it's still not great, & you're dealing with a cryogenic propellant that's constantly venting explosive gas (so it runs out of gas when parked for ~3 days, can't be parked in an enclosed space, & still doesn't deliver impressive range). I'm all for using hydrogen for things in general, but as I understand it there are hard physical limits that make it a poor choice for personal motor vehicles as we understand them today (size, safety & range in particular).

Methanol or renewable synthetic gasoline seem like they'll always outperform hydrogen for ICE cars.

Hydrogen airships would be cool though & we could make them safe with modern technology (both preventing fires & making the passenger compartment an under-slung survival cell with parachutes & giant airbags so a catastrophic loss is survivable)

Re: Porsche's idea for a six-stroke internal combustion engine

#288

Post by hnlmorg »

quintushoratius wrote: post #286
hnlmorg wrote: post #220

Earlier quoted context omitted.

You’re drastically overstating the differences between ICE and EV there. But that might be a side effect of American cars vs European cars.

I don't think I'm overstating anything. My wife and I have owned an EV since 2019. We also still have a couple of ICEs for me and my daughter. I'm not going to throw a car away just because. I see the cost savings of an EV up close and personal. The only downside has been range for long trips, but 364 days of the year that's not a problem and for the remaining days my ICE does the job. When that car dies, I'll rent o…

So you’re comparing EVs that are > 5 years old with ICE vehicles that are < 5 years old. Or there’s a massive disparity between American and European ICE cars under 5 years. But I definitely have never spent the kind of money on maintenance you’ve described on cars younger than 5 years old.

Re: Porsche's idea for a six-stroke internal combustion engine

#289

Post by jjtheblunt »

kevin_thibedeau wrote: post #284
mpol wrote: post #270

Earlier quoted context omitted.

Since hybrids are now so popular, rethinking how a gasoline engine fits into that picture might be worth it. Question is whether the market will shift again from hybrids to full EV, and if so, when. Designing and building a new engine might cost 5 billion, without a real certainty you will earn it back.

BEVs will never take over in North America. There are too many people spread out or living in places with no hope of charging infrastructure. People are going to balk when they find out they can only charge from a 20A circuit if even that is available.

who/what can only charge from a 20A circuit?

Re: Porsche's idea for a six-stroke internal combustion engine

#290

Post by hnlmorg »

vardump wrote: post #263
hnlmorg wrote: post #139

Earlier quoted context omitted.

Name me one mass produced consumer car that uses saltwater batteries.

Here seems to be one what the grandparent suggested, an EV with a SIB battery. https://www.electrive.com/2024/01/02/first-sodium-ion-batter...

China specific. So not really mass market. Though I am glad to see that there are cars entering the market with sodium ion batteries. That does give me hope for the long term future of EV.
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