7 ms·
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 fea
by markhahn 2y ago
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 valves so great? suppose we have some other mechanism to create the motion (solenoids?) or rotating valves? something electromagnetic appeals because it gives complete control over timing (rather than a crankshaft).
rotary engines are appealing, for the same contrarian reasons. but they seem to either have practical problems (wankel) or don't seem to be making it to market (peanut-shaped rotors, etc).
if 6 cycles makes sense (presumably in combustion physics), does it make any sense to burn in one chamber, then move those products to another chamber for some further (potentially different) cycle?
would it help if you could ignite from more than a single place? multiple plugs sounds like a bit of a pain, but could you generate an annular spark? would you want to control the location-timing of the combustion front? does rotating-detonation have any meaning in this context?
are there ways to reconsider the materials engineering of engines? make them dramatically cheaper, lighter? one of the best EV arguments is simplicity, but how much of current IC engineering is based on assumptions that can be broken?
- ithkuil 2y agoIirc Koenigsegg is using camless valves (using solenoids?)
- cr125rider 2y agoChristian and his team over there are actually pushing boundaries and doing really cool stuff.
- Too 2y agoFreevalve 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.
- elromulous 2y agoThis guy created a hobbyist version. Very impressive. https://youtu.be/E9KJ_f7REGw?si=hlMQIA9wNkQBniDX https://youtu.be/E9KJ_f7REGw?si=hlMQIA9wNkQBniDX
- Grazester 2y agoYes and no. Their 3 cylinder engine that was supposed to be in their 4 person mega car was to be the first product engine with it. That is no longer the case because rich people didn't like the idea of a 3 cylinder engine in their hybrid mega. As a result they are only producing a V8 hybrid version. Their v8s do not use the free valve.
- mpol 2y agoSince 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.
- DriftRegion 2y agoThe Obrist Zero Vibration Generator is exactly that: reimagining ICE tailored to series hybrid application. https://m.youtube.com/watch?v=0s5Du7qrPoM https://m.youtube.com/watch?v=0s5Du7qrPoM https://www.obrist.at/powertrain/components/ https://www.obrist.at/powertrain/components/
- kevin_thibedeau 2y agoBEVs 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.
- jjtheblunt 2y agowho/what can only charge from a 20A circuit?
- cyberax 2y agoLol.
- philistine 2y agoSo North America is limited to its large places? New York isn’t in North America. The last mile problem doesn’t negate the fact that for 85% of people an electric vehicle is possible in five years.
- kevin_thibedeau 2y agoNew York is mostly a semi-rural state where long distance travel in a BEV is a problem. One city where most residents don't drive doesn't mean anything.
- 01HNNWZ0MV43FF 2y agoCylinder solenoids are indeed a thing https://en.m.wikipedia.org/wiki/Free-piston_engine 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 https://en.m.wikipedia.org/wiki/Atkinson_cycle
- vvillena 2y agoAccording 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.
- dotancohen 2y ago> creating power in the compression phase Other than the potential energy of either the heat or the compressed gas, what "power" is created in the compression phase of a normal four stroke ICE?
- bestham 2y agoPumping losses are greater in a Otto cycle engine due to the increased resistance in compressing the whole stroke. In an Atkinson-cycle you get a longer power stoke than compression stroke and thus are more efficient. There is always another cylinder that get does i take during the short time when valve is open during compression in another cylinder. Thus that cylinder get some free assistance during intake.
- ryukoposting 2y agoRotating valves exist - look up "spool valves." Much like rotary engines, seal wear is the main drawback. Poppet valves also have the upside that they inherently spread air-fuel mixture out laterally.
- bob1029 2y ago> 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? A recuperated Brayton cycle operating at a fixed RPM could be competitive with existing approaches. It is also mechanically feasible to produce engines of this type with a single moving part, zero effective wear and no lubrication.
- physicsguy 2y agoThere was a lot of variation in aircraft engines before jet engines took over. They often used sleeve valves for e.g.