One of the joys I have in life is finding a unique way to answer a question that’s technically correct, but also not what the question asker is looking for. Usually, this is only for lighthearted stuff and results in a laugh from both parties. Such a thing just happened today, and it was great.
Matt wrote a Morning Dump that ended with: “What % of the new car market in the United States, in a vacuum, do you think should be electric cars?” Rockchops had a creative and technically correct answer:
To answer TBQ with utmost accuracy, 100%. Because ICE vehicles wouldn’t function in a vacuum. I’m not sure what the point would be as we’d all be dead, but you’d be better off with an electric vehicle.
Faerie Alex:
In a vacuum 100%, since all combustion engines rely on oxygen in the atmosphere to operate. We actually don’t have to guess at this – if we look at other (non-US) celestial bodies such as the Moon and Mars which lack oxygenated atmospheres, we indeed see 100% electrification.
Love the profile picture, Faerie Alex!
Even Cheap Bastard got in on the fun:
TBQ: 100% since electric cars like the lunar rovers can work in a vacuum but air breathing ICE cars do not.
Jason started our day with another post about Citroën facts. Goblin added more:
A bit of history here…
*** Andre Citroen was an extravagant genius. He first made a fortune in cogwheels in the early 1900s.
*** The double chevrons logo comes from the double chevron (herringbone) cogwheels he was selling. Depending on sources, the claim is he originally found the concept in Slovenia, or one of the Baltic states, or Poland, while on a trip. My money is on Slovenia, as the first Citroen dealership one can see in Slovenia after the Karavanken tunnel used to have a pair of huge (like 12ish ft) chevron cogwheels on display in the front.
*** Andre Citroen made his main fortune during WW1, making shells and other ammo.He was an amazing engineer combined with an extravagant compulsive gambler. He’d lose and win entire fortunes in a night. The legend goes that one night he opened at the Deauville casino with a 20 million francs loss, ended the night at a 80 million win, and gifted a Citroen car to every single croupier present.
***He was constantly in debt, always able to pay it back. Usually. Mostly.
***This all went till the early 30’s. He became heavily indebted – mostly to the Michelin brothers – with the development of the Traction Avant along with his extravagant life habits. The Traction Avant was released too early, and had plenty of teething problems. Andre Citroen and the Michelin brothers, it is claimed, were good friends.
*** The story becomes murkier from here. One day a small creditor presented an immediate payment request for a debt for 160000 (or was it 60000) francs – a ridiculously low sum by Citroen’s standards, which he expected to be able to pay in a snap. So he went around the usual suspects for a small loan to cover this.Turned out – no one would advance him a single centime anymore. The thing snowballed, and very quickly Citroen went bankrupt, with his largest creditors – the Michelin brothers quickly taking over everything. They then invested whatever little money was needed to fix the Traction Avant’s issues, and it became a hot seller.
*** History’s jury’s still out about the Michelin brothers’ role in this. Many claim that the whole operation with the small creditor popping out was orchestrated by them. From there, the opinions are split – some claim it was a nasty operation to steal Citroen from Citroen, others say that they simply were seeing no future for the company with Andre Citroen at the helm, considered he was dooming it, and decided to save it as it was toast anyway.
*** Andre Citroen died within an year. Many say the events killed him.
*** This is where this prototype comes in. The Michelin brothers were notoriously frugal, financially responsible and cautious. Just as the Peugeot family was. These guys didn’t do into extravagance or opulence. They took over in December 1934. This prototype is from 1934. Probably the first of many to go on the chopping block.
Some quick research seems to back this up. Have a great evening, everyone!
Top graphic image: SpaceX
It almost always ends up as a Dad Joke, huh?
What if André had kept his streak going and squoze out the Michelin boys? French cuisine would be in an absolute tizzy!
Please let me wake up in an alternate reality where foodies book seatings at restaurants with three Citroën hypercubes.
Chefs everywhere would be coveting their Michelin Lemons.
You can burn liquid fuel in space, you just need oxidizer. Obviously.
…actually, CAN we run piston engines without air if they have oxidizer supplied like liquid fuel rocket engines?
This actually does get at one of my frequently-cited advantages of BEVs, though. You can generate electricity anywhere, from almost anything. Delivering liquid fuel is an expensive, dangerous, time-consuming, and avoidable process. Particularly in remote locations, like outside of Earth’s atmosphere.
Sort of and only if you had the equipment (solar panels, wires, dissimilar metals, generators, etc).
OTOH people have been making ICE friendly combustible gasses and liquids for thousands of years from whatever is around so in a true Earthbound zombie apocalypse you’re probably best off with a plug in tri fuel hybrid.
The hybrid is a generator (well, in a series hybrid, but it’s a “power plant” either way); it doesn’t need to be part of the vehicle. “Making electricity from anything” includes ICE-friendly combustibles. That’s why I consider it fully one-sided.
There are going to be edge cases where you want fuel in the vehicle turning to mechanical energy now in some manner of apocalypse, though the resource management and maintenance disadvantages still seem worse to me.
If it’s at the point we’re considering whether things like “dissimilar metals and wires” are available, I think building/acquiring and maintaining an ICE may also be a stretch.
If it’s at the point we’re considering whether things like “dissimilar metals and wires” are available, I think building/acquiring and maintaining an ICE may also be a stretch.
There was a silly sci-fi tv series on TV some years ago in which all electric devices suddenly and mysteriously stopped working, including light bulbs. Civilization, predictably collapsed. The only way to get around was by horse or foot but eventually the old steam trains and riverboats were running again. So external combustion is an option (as is diesel) even if electricity isn’t.
Rocket fuel and oxidizer tends to be highly corrosive so you might not get far. If mechanical power is your goal you’d be better off with a turbine since the metallurgy on those would be the same as the turbo pumps used on existing rocket motors.
Oxidizers by definition are trying to combine with anything available.
They should try buying *anything* a drink first.
Something brisant, perhaps?
Something absenthe will do.
Good enough!
ICE engines also need ambient atmosphere – you can’t get them to suck if there’s nothing to suck against. So rather than injecting oxygen direct to the pistons you would have to have some sort of atmospheric chamber to suck from which was regularly replenished with gas to keep the pressure within limits. On the plus side overpressuring this chamber would remove the need for turbocharging.
On the blow side a little back pressure is desirable for exhaust flow, so you would probably want some sort of atmospheric chamber on the exhaust to keep a consistent pressure there too.
Hi, former exhaust system designer here. We never want back pressure. What we’d like for a naturally aspirated ICE is tuned lengths of primaries and secondaries to help evacuate the cylinder, but access to a large volume of vacuum would do the job much better.
You know best!
I’ve spoken to two people that think they have solved the design of exhaust systems.
They sound the same despite not knowing each other, and learning on nearly opposite system types. They both say the reference books are wrong. Beyond that, they wouldn’t explain. My opinion is that they solved something involving laminar separation. One nearly says that.
More information seems proprietary.
But I’m still curious.
That “chamber” can be just your oxidizer tank, fed through a pressure regulator that acts as a throttle body. Maybe running that to a plenum would be good for scavenging, but the main thing is that air coming in through a pressure regulator or through a throttle body is basically the same thing, just a little more mechatronically complex due to the need to account for changing pressure in the tank as the supply dwindles.
As Dave said, 4-stroke engines don’t need back-pressure. The misconception comes from people not fully understanding the concept of scavenging. A thinner exhaust header tube increases air velocity, just like pursing your lips allows you to blow out a candle that you might not be able to blow out with your mouth wide open. Adjusting air velocity to the correct range is one of two ways to change an exhaust system’s scavenging properties, the other is changing the lengths of the primaries.
But back to air velocity, it enables the exhaust air, as it rushes out, to create a vacuum in the chamber as the piston reaches top dead center and the intake valve starts to open, sucking out the last vestiges of exhaust gas and helping to draw the first bit of intake air into the cylinder during the moment of valve overlap.
In more detail, the piston travels up and pushes out the exhaust gas, but as it reaches top dead center is slows down and eventually stops before it starts to pull in the intake air. When the cylinder stops, if this was a static system, we’d be stuck with the exhaust gas that’s left in the chamber, but because the gas traveling down the exhaust port has mass and velocity, its momentum creates a vacuum in the chamber that helps both remove remaining exhaust gas and suck in the incoming intake charge.
Notice that the purpose of tuning air velocity is not to create back-pressure, but to create a vacuum at just the right time.
But old-school tuners didn’t have the internet to research this or the time to grab some thick physics books, and a lot of modern ones listen to the old wisdom without verifying it, so to them, thinner pipe = back pressure.
Probably not for long, or not without serious modifications. Remember that ICE engines are designed to exhaust to atmospheric pressure.
Also, if you are talking about space specifically, rather than a general vacuum, the microgravity environment would screw with the lubrication system
H2 and O2 can (and have) been used in an engine designed for space applications. Lubrication in 0-G is the tricky part, not the combustion part. Vickers in the 60’s, ULA’s IVF-ICE most recently
Yes. They only need an air supply to run current engines.
Cummins is working on hydrogen powered engines. Exhaust would be water same as the space shuttle.
Shuttle boosters burned aluminum as fuel.
There have been drag cars that use compressed air tanks instead of turbo- or super chargers. Apparently it works quite well because it’s totally RPM-independent and the expansion cools the air too, which gives an extra power boost. In fact apparently the intake icing up can become an issue instead!
I always wondered if using a compressed tank to cool the intake was practical.
Apparently so, if managed well
Technically correct is the best kind of correct.
…technically.
It’s also the only kind of correct.
Yeah? My favorite new thing is to say something is “directionally correct.” It’s like, “you’re headed in the right direction– good for you!”
vive le historie lol