No crankshaft, no problem: Toyota's free piston engine is brilliant(roadandtrack.com)
roadandtrack.com
No crankshaft, no problem: Toyota's free piston engine is brilliant
http://www.roadandtrack.com/go/out-of-turn-toyota-engine
18 comments
> cars used to weigh twice as much which halved city fuel economy
Nit: this is actually the other way around, cars have been gaining weight - so much that it has swallowed most of the mileage improvement we'd otherwise have gotten from other tech improvements.
See eg http://newsoffice.mit.edu/2011/cars-on-steroids-0104
Nit: this is actually the other way around, cars have been gaining weight - so much that it has swallowed most of the mileage improvement we'd otherwise have gotten from other tech improvements.
See eg http://newsoffice.mit.edu/2011/cars-on-steroids-0104
They were designed for cost-effectiveness in an era of cheap fuel. Electric transmission wasn't feasible on the car scale until cheap microelectronics arrived. It was confined to diesel-electric locomotives.
What people might not think about so much is that weight reduction is as important if not more important than the advancements we make in the engine.
When Rocky Mountain Institiute was working on their hyper car concept, I believe the researcher said that weight reduction was more important than electric or gas engine.
I think he said something like for every pound you save, you actually reduce an extra 2-3 pounds of supporting materials elsewhere. Lighter cars need less HP, you can reduce some of the support bracing as it's not as heavy of a vehicle, etc...
Making cars super light would do a lot of good and so every time I see a giant battery for electric cars or a 2nd engine to act as a backup, I wonder how much that is costing in terms of weight and MPG.
When Rocky Mountain Institiute was working on their hyper car concept, I believe the researcher said that weight reduction was more important than electric or gas engine.
I think he said something like for every pound you save, you actually reduce an extra 2-3 pounds of supporting materials elsewhere. Lighter cars need less HP, you can reduce some of the support bracing as it's not as heavy of a vehicle, etc...
Making cars super light would do a lot of good and so every time I see a giant battery for electric cars or a 2nd engine to act as a backup, I wonder how much that is costing in terms of weight and MPG.
Along with a weight reduction, they said that, "It can also be run like a diesel, using compression rather than a spark plug to ignite its fuel mixture." This is important as spark plugs require a decent amount of energy to function.
spark plugs require a decent amount of energy to function
Are you sure about that?
According to [0], "To ignite a stoichiometric air-fuel mixture (14:1) approximately 0.2 milliJoules of spark energy are required. Very rich or lean mixtures can require as much as 3 mJ."
[0] http://www.mr2.com/TEXT/DavidKucharczyk/ignition.html
Are you sure about that?
According to [0], "To ignite a stoichiometric air-fuel mixture (14:1) approximately 0.2 milliJoules of spark energy are required. Very rich or lean mixtures can require as much as 3 mJ."
[0] http://www.mr2.com/TEXT/DavidKucharczyk/ignition.html
(0.2 millijoules * 6 * 3000) / minute = 0.06 watts
So yea, not much...
So yea, not much...
There are lots of designs where the car is significantly lighter than a typical vehicle driving on American or European roads. The problem with them is that if you get in an accident, you are much more likely to suffer much more damage. There are in fact regulations in the US that effectively require you to build heavier cars. Motorcycles and scooters are great examples of personal transportation that are lightweight and can get ridiculous fuel economy, but in a Vespa vs 18 wheeler, the Vespa will lose every time, which is why you don't see them on the freeway.
One important question is how much you really care about efficiency if you're getting most of your energy from electricity. Electricity isn't free, and it still pollutes depending on what your local generating capacity looks like, but it's a lot better than even the most efficient gasoline.
The problem with most electric cars right now is range, which is due to the inherent cost of the batteries. But it's largely psychological, as most people's driving in most situations is within the range of a reasonable electric vehicle. It's just exceptional circumstances when it's not enough.
Thus, paradoxically, adding a gasoline range extender to an electric car could really help enable electric driving considerably. And if the car drives 90% on electricity, the efficiency of the gas engine doesn't matter too much. It's just there as a backup.
I almost bought a plug-in hybrid last year. A Volt or similar would let me do a ton of pure electric driving, while still having the option to go farther. A Leaf or similar just wouldn't cut it for me, because a car that covers 90% of my driving isn't good enough. But if it can cover 100%, with 90% on electricity, that's a big gain. Ultimately I didn't get one, because they're still a bit too compromised (the Volt only seats 4, others have tiny cargo space), but range extenders could be an important bridge measure as batteries slowly improve, and the extra weight isn't all that important in many cases.
The problem with most electric cars right now is range, which is due to the inherent cost of the batteries. But it's largely psychological, as most people's driving in most situations is within the range of a reasonable electric vehicle. It's just exceptional circumstances when it's not enough.
Thus, paradoxically, adding a gasoline range extender to an electric car could really help enable electric driving considerably. And if the car drives 90% on electricity, the efficiency of the gas engine doesn't matter too much. It's just there as a backup.
I almost bought a plug-in hybrid last year. A Volt or similar would let me do a ton of pure electric driving, while still having the option to go farther. A Leaf or similar just wouldn't cut it for me, because a car that covers 90% of my driving isn't good enough. But if it can cover 100%, with 90% on electricity, that's a big gain. Ultimately I didn't get one, because they're still a bit too compromised (the Volt only seats 4, others have tiny cargo space), but range extenders could be an important bridge measure as batteries slowly improve, and the extra weight isn't all that important in many cases.
Seems like needing the piston to change directions is a waste of momentum. What about a similar design where a ball is propelled around the inside of a circular doughnut to generate electricity?
Or a Wankel engine[1]
[1] http://en.wikipedia.org/wiki/Wankel_engine
[1] http://en.wikipedia.org/wiki/Wankel_engine
A rotary engine isn't free-piston, but it also doesn't have reciprocating parts. But it also shows there are other challenges to efficiency than reciprocating pistons.
I think the pressure would go around the donut on both sides and equalize.
Wouldn't a more obvious solution be to change the direction by adding a second combustion chamber on the other side?
That works great until you miss ignition on the opposite side, then wham it bottoms out and destroys the other side of the engine.
A gas spring is a pretty simple mechanism and can't misbehave (too bad you can't put it to work, though -- probably a lot of heat being wasted compressing it).
A gas spring is a pretty simple mechanism and can't misbehave (too bad you can't put it to work, though -- probably a lot of heat being wasted compressing it).
This would be why you wouldn't run 2 pistons facing each other sharing common valve and ignition set to balance?
Is your question rhetorical ? Because that's how ITER (nuclear fusion reactor) generate electricity in a nutshell, if you replace the ball by plasma.
source : https://www.iter-india.org/images/fusion_experiments2.jpg
source : https://www.iter-india.org/images/fusion_experiments2.jpg
That diagram is about the energy inputs to heat the plasma.
Energy output to generate electricity is quite indirect: hot neutrons escape the magnetic containment and are caught in a lithium blanket. This produces tritium from the nuclear reaction between the neutrons and lithium nuclei, and heat. The blanket is cooled with water which is used to drive a conventional steam turbine generator set.
See the last paragraph of the reactor overview at http://en.m.wikipedia.org/wiki/ITER and note that they do not plan to generate electricity from ITER: it is purely experimental.
Energy output to generate electricity is quite indirect: hot neutrons escape the magnetic containment and are caught in a lithium blanket. This produces tritium from the nuclear reaction between the neutrons and lithium nuclei, and heat. The blanket is cooled with water which is used to drive a conventional steam turbine generator set.
See the last paragraph of the reactor overview at http://en.m.wikipedia.org/wiki/ITER and note that they do not plan to generate electricity from ITER: it is purely experimental.
Too hard to seal. Ask a RX8 owner about rotor apex seals sometime. The bane of their existence.
In this new motor there's nitrogen on the other end of the piston that provides "rebound". It's probably inside the coolant jacket as well to prevent expansion and the loss of efficiency that would bring.
In this new motor there's nitrogen on the other end of the piston that provides "rebound". It's probably inside the coolant jacket as well to prevent expansion and the loss of efficiency that would bring.
Ex RX-7 owner here. Not much room in the back of one of those things, but I always had room for cans of oil :-)
Wonderful cars. I'd buy an RX-9 if they ever built one, but they're never going to. So I have to motorcycle instead, could be worse :-)
Wonderful cars. I'd buy an RX-9 if they ever built one, but they're never going to. So I have to motorcycle instead, could be worse :-)
Same. Mine didn't burn much oil, but would refuse to start when the engine was warm because of the weak compression. Would fire right up when it was cool though.
Loved how it handled and the 9,000 rpm redline.
Loved how it handled and the 9,000 rpm redline.
It sure is a pain in the ass when that happens. I have a chipped ECU so I don't have to get out and pull the fuse to get it started, but I haven't installed it yet.
One of my cats is gutted and my exhaust is rusted to hell - right now my fuel economy is shit (~10mpg). This should actually improve when I put the Racing Beat exhaust in but then I have to upgrade the injectors and air intake and port the turbo.
My 10th Anniversary is still bone-stock and I'm sad about having to change it.
One of my cats is gutted and my exhaust is rusted to hell - right now my fuel economy is shit (~10mpg). This should actually improve when I put the Racing Beat exhaust in but then I have to upgrade the injectors and air intake and port the turbo.
My 10th Anniversary is still bone-stock and I'm sad about having to change it.
I know a few people who've owned RX-7s and 8s, one said it was the only car he worried about running out of oil before fuel. Beautiful cars, but they're a bit high maintenance.
10th Anniversary RX-7 owner here.
If you actually maintain your car and don't treat it like a toaster, it's not too bad. They combust oil to lubricate the engine, so you just have to make sure it has oil. If your oil metering pump is electronic ('89 and after), run it with premix when you fill up. And drive your car hard & rev past 6k once a drive or so to clear out the carbon. Yes, I've gotten a speeding ticket for doing this.
I love my car. It's about to hit 100k miles and it's a Turbo and despite what the naysayers say, it hasn't blown up yet and still has good compression.
The electrical issues are far worse than the engine ones. The engine is bulletproof if you do your basic maintenance and listen to your car.
Every sports car is high maintenance. The Alfa, Porsche and Ferrari owners have it as bad or worse - people just treat exotic powerplants like voodoo - I sure paid a hell of a lot less than they did though.
I would rather pull and rebuild my entire engine than change the power steering fluid on a recent Porsche. The latter has a nightmarish set of steps likely to break all sorts of tiny plastic bits that cost more to replace than my engine rebuild kit would...
If you actually maintain your car and don't treat it like a toaster, it's not too bad. They combust oil to lubricate the engine, so you just have to make sure it has oil. If your oil metering pump is electronic ('89 and after), run it with premix when you fill up. And drive your car hard & rev past 6k once a drive or so to clear out the carbon. Yes, I've gotten a speeding ticket for doing this.
I love my car. It's about to hit 100k miles and it's a Turbo and despite what the naysayers say, it hasn't blown up yet and still has good compression.
The electrical issues are far worse than the engine ones. The engine is bulletproof if you do your basic maintenance and listen to your car.
Every sports car is high maintenance. The Alfa, Porsche and Ferrari owners have it as bad or worse - people just treat exotic powerplants like voodoo - I sure paid a hell of a lot less than they did though.
I would rather pull and rebuild my entire engine than change the power steering fluid on a recent Porsche. The latter has a nightmarish set of steps likely to break all sorts of tiny plastic bits that cost more to replace than my engine rebuild kit would...
> If you actually maintain your car and don't treat it like a toaster, it's not too bad.
This. Never forget basic maintenance. I had a 1981 RX-7 and had over 194,000 miles on it when I got rid of it in 1998. (I still have the concrete blocks I'd put in the back when it snowed.)
This. Never forget basic maintenance. I had a 1981 RX-7 and had over 194,000 miles on it when I got rid of it in 1998. (I still have the concrete blocks I'd put in the back when it snowed.)
The problem with the RX-8s isn't the rotor apex seals (any more so than any other rotary), it's actually injection. A design oversight with how they inject oil in the '04-'06 models causes the engine to not be lubricated properly and this will cause a lot of problems. Even though they fixed it after '06, it's still not perfect. Like the '89 and after RX-7s, the RX-8 needs to run with premix.
But generally you want to avoid buying an '04-'06 RX-8 used.
But generally you want to avoid buying an '04-'06 RX-8 used.
Elaborate?
With the initial design they used 2 oil injection nozzles per rotor and basically there was insufficient coverage due to that and the way they were angled.
After the '06 model year they went to 3 per rotor and angled third nozzle to compensate.
That's how I understand it from the reading I've done and conversations with mechanics & owners I know. I've yet to work on one of these with my own two hands. I'm strictly interested in 7s and earlier. I inspected a few 8s for potential purchase but they all had problems that I wasn't interested in dealing with.
After the '06 model year they went to 3 per rotor and angled third nozzle to compensate.
That's how I understand it from the reading I've done and conversations with mechanics & owners I know. I've yet to work on one of these with my own two hands. I'm strictly interested in 7s and earlier. I inspected a few 8s for potential purchase but they all had problems that I wasn't interested in dealing with.
Ah, ok.
What problems does the 8 have?
What problems does the 8 have?
Nono, each car I looked at had problems individually.
What I talked about earlier is the main problem for RX-8s. Beyond that they're about as reliable as other cars of the same era and classification. They do come with about as much performance as you can get out of them from the factory though. They're not that interesting as anything other than a street cruiser.
What I talked about earlier is the main problem for RX-8s. Beyond that they're about as reliable as other cars of the same era and classification. They do come with about as much performance as you can get out of them from the factory though. They're not that interesting as anything other than a street cruiser.
You could have a reciprocating engine instead. Wankel engines have problems due to sealing being difficult (as would your idea, explosive gases escape at the edge of the sphere), as I understand (I've not studied it in depth), but a reciprocating engine would seemingly have no more [in fact less] issues with being sealed than 2 parallel pistons. Have the first combustion chamber push the piston one direction past the coils and have a second chamber at the opposite end push the piston back. Any excess movement might be able to be used for pre-compression?
Of course many people have thought of this before (don't you hate it when that happens! ;0)) - http://www.youtube.com/watch?v=2SlwoBLspTQ shows 2 such engines.
http://www.youtube.com/watch?feature=player_detailpage&v=yV0... shows another idea, 2 pistons either side of a single combustion chamber.
Of course many people have thought of this before (don't you hate it when that happens! ;0)) - http://www.youtube.com/watch?v=2SlwoBLspTQ shows 2 such engines.
http://www.youtube.com/watch?feature=player_detailpage&v=yV0... shows another idea, 2 pistons either side of a single combustion chamber.
If you follow that line of thought to it's conclusion, you end up with gas turbine (Brayton cycle).
Yes, that's what I thought. Many people seem to ignore gas turbine option, even if those are very reliable and efficient power sources.
If there's interest towards different engine designs, it might be a good idea to check this out too:
https://en.wikipedia.org/wiki/Wave_disk_engine and another interesting design: https://en.wikipedia.org/wiki/Swing-piston_engine There surely isn't shortage of engine designs, most of these designs are from 1800's. So nothing new.
Don't forget that for an electric motor you need a sine shaped AC and not DC so it's pretty convenient that this design produces exactly that. Whereas with a "continuous" design you'd need to make it AC.
If your motor needs AC, you already have an inverter, since the battery produces DC.
I hear this quite often, but I don't quite see how this is true. Each piston is hooked to a crankshaft, which is hooked to a flywheel. Even with a single piston, the energy of it slowing down and reversing is absorbed in the flywheel, which is in turn used to propel it in the opposite direction. Add multiple pistons, and the energy of slowing down is again used to accelerate another piston.
Just think of any spot on a wheel representing an arbitrary amount of mass. Spin the wheel, and the only thing slowing it down is friction -- not that spot constantly changing direction.
Just think of any spot on a wheel representing an arbitrary amount of mass. Spin the wheel, and the only thing slowing it down is friction -- not that spot constantly changing direction.
This article is specifically about a piston engine that does not have a crankshaft.
> Seems like needing the piston to change directions is a waste of momentum.
It's not, in a closed system momentum is conserved [1] so without friction, a free engine would rotate forever.
Also there is not conceptual difference between an engine and a ball sniping in a donut. In both case, the piston or the ball have to change direction (the piston has to change direction more abruptly though)
[1] http://en.wikipedia.org/wiki/Momentum#Conservation
It's not, in a closed system momentum is conserved [1] so without friction, a free engine would rotate forever.
Also there is not conceptual difference between an engine and a ball sniping in a donut. In both case, the piston or the ball have to change direction (the piston has to change direction more abruptly though)
[1] http://en.wikipedia.org/wiki/Momentum#Conservation
What is forgotten here is a reduction of vibrations.
The crankshaft works as a (cheap) synchronizer for piston movement and can reduce vibrations when phases are aligned in special way.
Motor vibrations are big deal - they take energy and also reduce quality of car.
The crankshaft works as a (cheap) synchronizer for piston movement and can reduce vibrations when phases are aligned in special way.
Motor vibrations are big deal - they take energy and also reduce quality of car.
This is why they mention that a two cylinder engine is balanced; e.g. a boxer configuration.
It's mentioned obliquely:
Even better, a two-cylinder FPEG is inherently balanced
I guess electronic timing is also up to the task of keeping things running smoothly without mechanical synchronization.
Even better, a two-cylinder FPEG is inherently balanced
I guess electronic timing is also up to the task of keeping things running smoothly without mechanical synchronization.
The article mentioned a two-cylinder configuration where the movements of two pistons would be mirroring each other, nullifying the vibrations.
If you enjoyed this article, check out http://jalopnik.com/what-its-like-to-ride-in-a-car-with-the-...
I remember seeing something similar to this a year ago in a documentary series concerning the small Swedish supercar manufacturer Koenigsegg. See it here: https://www.youtube.com/watch?v=Bch5B23_pu0&list=PLHa6PXrV-y.... It sounds really interesting.
All it needs to do is generate motion, so they made it like those flashlights you charge by shaking them. Reciprocal! What will be revolutionary will be performing this with some kind of rotary engine.
The Jaguar C-X75 almost made it into production - and it had miniature gas turbines linked to generators feeding the batteries and wheel motors:
http://en.wikipedia.org/wiki/Jaguar_C-X75
Given the current popularity of hybrid hyper-cars from Porsche, McLaren and Ferrari it would be interesting to see if something like the Jaguar is tried again.
http://en.wikipedia.org/wiki/Jaguar_C-X75
Given the current popularity of hybrid hyper-cars from Porsche, McLaren and Ferrari it would be interesting to see if something like the Jaguar is tried again.
Much older than that was the Chrysler Turbine car:
http://en.wikipedia.org/wiki/Chrysler_Turbine_Car
This was quite literally a lower power jet aeroplane turbine used to power the car.
I would imagine that this would have been great on fuel economy on the highway, but terrible in cities.
http://en.wikipedia.org/wiki/Chrysler_Turbine_Car
This was quite literally a lower power jet aeroplane turbine used to power the car.
I would imagine that this would have been great on fuel economy on the highway, but terrible in cities.
That seems to have used a "conventional" mechanical transmission rather than using the turbine to generate electricity to feed the electric motors.
Still pretty cool though!
Still pretty cool though!
If you're interested there is a very good book called Chrysler's Turbine Car: The Rise and Fall of Detroit's Coolest Creation.
http://www.amazon.com/Chryslers-Turbine-Car-Detroits-Creatio...
http://www.amazon.com/Chryslers-Turbine-Car-Detroits-Creatio...
>great fuel economy on the highway
Small turbines generally have terrible fuel economy. The Wikipedia page you quote says "...fuel consumption was excessive"
Small turbines generally have terrible fuel economy. The Wikipedia page you quote says "...fuel consumption was excessive"
This is what I was thinking about too. Rotation is better than reciprocal line movement.
While in terms of reliability, simplicity and power to weight ratios turbine engines are great, they still suffer from low compression ratios.
If I remember correctly about 3 to 1, compared to 10 in 1 for petrol engines and nearly 20 to 1 for diesel engines.
Thermodynamically this makes it very difficult to achieve high efficiency.
If I remember correctly about 3 to 1, compared to 10 in 1 for petrol engines and nearly 20 to 1 for diesel engines.
Thermodynamically this makes it very difficult to achieve high efficiency.
"If I remember correctly about 3 to 1,"
That seemed strange to me given multistage compressors. Maybe 3:1 is true for a micro turbines, but for larger jets wikipedia says the pressure ratio is 30:1 to 40:1 citing the Trent 900 at 39:1 and the GE90 at 42:1.
Which according to the same article says that a 40:1 PR is equivalent to a 15:1 compression ratio.
http://en.wikipedia.org/wiki/Overall_pressure_ratio
That seemed strange to me given multistage compressors. Maybe 3:1 is true for a micro turbines, but for larger jets wikipedia says the pressure ratio is 30:1 to 40:1 citing the Trent 900 at 39:1 and the GE90 at 42:1.
Which according to the same article says that a 40:1 PR is equivalent to a 15:1 compression ratio.
http://en.wikipedia.org/wiki/Overall_pressure_ratio
I stand corrected. I'm sure I had read that some time ago but I can't find a reference at the moment.
> What will be revolutionary will be performing this with some kind of rotary engine.
You mean, like a turbine?
You mean, like a turbine?
>You mean, like a turbine?
I think he means like a Wankel engine:
http://en.wikipedia.org/wiki/Wankel_engine
I think he means like a Wankel engine:
http://en.wikipedia.org/wiki/Wankel_engine
> You mean, like a turbine?
There are rotary internal combustion engines, such as the Wankel engine. It has a triangular "rotor-piston" spinning in a circular cylinder and goes through four "strokes" per revolution.
Mazda is a manufacturer that utilizes rotary engines in production cars today, particularly in their high performance models.
http://en.wikipedia.org/wiki/Wankel_engine
There are rotary internal combustion engines, such as the Wankel engine. It has a triangular "rotor-piston" spinning in a circular cylinder and goes through four "strokes" per revolution.
Mazda is a manufacturer that utilizes rotary engines in production cars today, particularly in their high performance models.
http://en.wikipedia.org/wiki/Wankel_engine
They last used it in the RX-8, which they discontinued in 2012.
(at least, for production consumer vehicles)
(at least, for production consumer vehicles)
Ok, I didn't know the RX-8 was discontinued. They do, however, still build the rotary engines for use in racing applications, such as the Star Mazda racing series in the US.
I didn't mean to be picky, I just had some vague memory of an article talking about how no production car was going to have a Wankel anymore and after I checked decided it reasonable to post the clarification.
>Even better, a two-cylinder FPEG is inherently balanced and would measure roughly 8 inches around and 2 feet long. An engine of that size and type could generate 15 hp, enough to move a compact electric vehicle at highway speed after its main drive battery has been depleted.
Is 15 HP really enough to move a car at highway speeds? I had a CBR250 motorcycle that produced 22-24 HP and weighed around 350 pounds, and it was not particularly great on the highway. It's hard for me to imagine a car that's 3+ times heavier with less horsepower being safe on a highway.
Is 15 HP really enough to move a car at highway speeds? I had a CBR250 motorcycle that produced 22-24 HP and weighed around 350 pounds, and it was not particularly great on the highway. It's hard for me to imagine a car that's 3+ times heavier with less horsepower being safe on a highway.
[deleted]
This could be used as a transition from gas to battery cars. Why? Currently one of the most important reasons holding back companies from producing electric cars is the lack of good batteries, but with this, companies can produce cars that convert gas to electricity in order to drive an electric motor. After a few years, when gas becomes even more expensive and batteries get better, we can switch this mechanism to batteries, and that's it.
Pretty cool, and I wonder if you could build the piston with two "heads" and put a cylinder head on either end and just shoot it back and forth. Magnetics of course have a hard time at high temperatures, so I'm not sure how you generate the stator field reliably.
The problem would be startup and shutdown timing. Any circumstance where you had a "missed" ignition (which occurs more often than you'd think) would result in a catastrophic failure (pistol slams in to the opposing head).
Anyone know why hybrids don't use turbine generators? As I understand it, they are more efficient than even the best reciprocating engine. Aside from solar and wind, every large-scale generating station uses turbines, for example.
IIRC, turbines are really ineffecient at small scales.
It's only when you get up to large scales that they start making sense.
It's only when you get up to large scales that they start making sense.
they are slow to get to speed and loud.
Pardon my ignorance, but the video does not show and I am interested to see if they modified the system, but what draws the piston back towards the spark plug?
IIUC, a spring.
It's a gas spring, similar to a car shock.
It's not drawn, it's pushed, by the pressure built up in the "gas spring chamber".
I believe this is what Chevy Volt does, and it's brilliant. There are two reasons I like this design. First, the fossil fuel engine in the Volt spins at only three pre-defined speeds so it can be optimized better. By contrast, your normal car engine has to run at both 900 RPM and 6500 RPM, with the best fuel economy somewhere between 2000 and 3000 RPM. Heck, you could shut the Volt's engine entirely while it's "idling" and not have to worry about stop & go traffic: the engine is independent of the wheels.
Second, and this is admittedly more long term, it doesn't really matter what type of engine you put into the Volt. This thought was presented to me by one of their dealers, but it makes a lot of sense. The current engine is a "tried and true" gasoline job. But if Chevy found that diesel or bio fuel, or natural gas worked better, they could swap it out without redesigning the rest of the drivetrain.
I may sound like a walking billboard for the Volt, but I am honestly not. I don't own one, and do not work for Chevy/GM. I do happen to think that the Volt is the best compromise between price, range on batteries, and ability to drive long distances. While Tesla's are very cool, I think the Volt is a much more gradual transition from gas to electric.
Second, and this is admittedly more long term, it doesn't really matter what type of engine you put into the Volt. This thought was presented to me by one of their dealers, but it makes a lot of sense. The current engine is a "tried and true" gasoline job. But if Chevy found that diesel or bio fuel, or natural gas worked better, they could swap it out without redesigning the rest of the drivetrain.
I may sound like a walking billboard for the Volt, but I am honestly not. I don't own one, and do not work for Chevy/GM. I do happen to think that the Volt is the best compromise between price, range on batteries, and ability to drive long distances. While Tesla's are very cool, I think the Volt is a much more gradual transition from gas to electric.
This article is more about using the linear electrical generator on the piston than it is the configuration of the power train. No vehicles on the road today have anything similar to what is discussed in the article.
Also, I'm not sure about the current model, but there was a bunch of kerfuffle over the Volt not really being a strict electric hybrid:
http://www.plugincars.com/exclusive-chevrolet-volt-chief-eng...
Some of the time, at least in the edition discussed there, energy from the engine goes to the wheels without ever becoming electricity. Maybe they changed it in later models (but I sort of doubt it, the capability is there because it can be the most efficient way to use the engine).
Also, I'm not sure about the current model, but there was a bunch of kerfuffle over the Volt not really being a strict electric hybrid:
http://www.plugincars.com/exclusive-chevrolet-volt-chief-eng...
Some of the time, at least in the edition discussed there, energy from the engine goes to the wheels without ever becoming electricity. Maybe they changed it in later models (but I sort of doubt it, the capability is there because it can be the most efficient way to use the engine).
I did not know that. Looking at the Wikipedia article for the Volt [1] I can see that the gasoline engine may provide additional mechanical energy to turn the wheels, but it's only to assist the primary and secondary electric motors.
In either case, I am not a purist going after a 100% electric car. I want to get more miles per dollar, and I want to produce less CO2 per mile. The Volt seems to do that, while still letting me drive from NYC to LA and back without having to spend more than three minutes at any given gas station. More importantly, any gas station will do, since it can run on just gas. For a daily commute, it will likely run 100% electric since the battery won't be depleted. To me, this is a great combination.
[1] http://en.wikipedia.org/wiki/Chevrolet_Volt#Drivetrain
In either case, I am not a purist going after a 100% electric car. I want to get more miles per dollar, and I want to produce less CO2 per mile. The Volt seems to do that, while still letting me drive from NYC to LA and back without having to spend more than three minutes at any given gas station. More importantly, any gas station will do, since it can run on just gas. For a daily commute, it will likely run 100% electric since the battery won't be depleted. To me, this is a great combination.
[1] http://en.wikipedia.org/wiki/Chevrolet_Volt#Drivetrain
Nothing in your first paragraph is special to the Volt. Any hybrid, aside from the less advanced "motor assist" designs (found in earlier Honda hybrids) get the same advantages. A Prius can keep the engine at a happy RPM throughout due to effectively having a CVT, and it can not only shut off the engine when stopped, but even when moving up to 40+MPH.
There are some interesting consequences of a pure serial hybrid design like the Volt (although the Volt isn't quite a pure serial design), but friendlier RPM and the ability to shut the engine down aren't it.
There are some interesting consequences of a pure serial hybrid design like the Volt (although the Volt isn't quite a pure serial design), but friendlier RPM and the ability to shut the engine down aren't it.
It's simple: A car needs a source of energy. Then a 15 gallon tank of gasoline is just super tough to beat. Can beat it a little with a 15 gallon tank of Diesel oil. A few hundred pounds of batteries with a charge from the electric grid? You gotta be kidding.
Now, what to do with that liquid in that 15 gallon tank is a question, but the basic fact remains. Did I mention that that fact is simple? A car needs energy, and that 15 gallon tank is tough to beat. For the rest, we have a lot of possibilities, but that 15 gallon tank is tough to beat.
Now, what to do with that liquid in that 15 gallon tank is a question, but the basic fact remains. Did I mention that that fact is simple? A car needs energy, and that 15 gallon tank is tough to beat. For the rest, we have a lot of possibilities, but that 15 gallon tank is tough to beat.
Gee, some people need some help: Did I mention, a 15 gallon tank is tough to beat? Electric power, that is, without a tank of gasoline or Diesel, for the energy for a car, is tough, super tough, for now and a long time, too tough to store. It's tough. Storing electric energy is tough, too tough for a car and likely also for wind and solar to feed the grid. Yes, there are ways to store the energy from wind and solar for the grid, but those ways are too expensive, by a factor of about 2, over other means of electric power generation that do not need storage, even if the power from wind and solar are just free, as in totally free, as in $0.00 per megawatt year.
So, let's look at an example, say, Tesla. I just went to their Web site and looked at charging time and saw
> During the work week I charge only at work during an 8hr shift from a 110 outlet. I only live 6 miles from work. I usually get ~30 miles of charge in 8 hours
So, right, 8 hours of charging for 30 miles of driving. Lots of cars can go 30 miles on one gallon of gasoline that takes about, what, 20 seconds, to pump. Diesel, maybe 45 miles.
The car, sure, it can still drive the wheels with electric motors, but, to make any sense, we store little or no electric energy in the car. Instead, the energy for the car is stored in a 15 gallon tank of gasoline or Diesel.
We had electric cars going way back to the beginning of cars. Why? Because lead acid batteries and electric motors were already old things. And, a battery much better than lead acid is still tough to get; indeed, we still use lead acid batteries in cars for, say, the starting motor.
The main problem with electric cars remains the batteries. As a Ford executive said long ago, build me a good battery and I will build you a good electric car. We are still waiting for a good battery, say, comparable with a 15 gallon tank of gasoline, in range, capital expense, operating expense, durability, and 'recharging' time.
So far, a Tesla is a toy for rich people. Sorry 'bout that.
I could like an electric car; it would have a lot of advantages. The problem is the battery. And that's been the problem for about 100 years.
So, let's look at an example, say, Tesla. I just went to their Web site and looked at charging time and saw
> During the work week I charge only at work during an 8hr shift from a 110 outlet. I only live 6 miles from work. I usually get ~30 miles of charge in 8 hours
So, right, 8 hours of charging for 30 miles of driving. Lots of cars can go 30 miles on one gallon of gasoline that takes about, what, 20 seconds, to pump. Diesel, maybe 45 miles.
The car, sure, it can still drive the wheels with electric motors, but, to make any sense, we store little or no electric energy in the car. Instead, the energy for the car is stored in a 15 gallon tank of gasoline or Diesel.
We had electric cars going way back to the beginning of cars. Why? Because lead acid batteries and electric motors were already old things. And, a battery much better than lead acid is still tough to get; indeed, we still use lead acid batteries in cars for, say, the starting motor.
The main problem with electric cars remains the batteries. As a Ford executive said long ago, build me a good battery and I will build you a good electric car. We are still waiting for a good battery, say, comparable with a 15 gallon tank of gasoline, in range, capital expense, operating expense, durability, and 'recharging' time.
So far, a Tesla is a toy for rich people. Sorry 'bout that.
I could like an electric car; it would have a lot of advantages. The problem is the battery. And that's been the problem for about 100 years.
Nothing in the grandparent comment invites your first rant. Except maybe I do happen to think that the Volt is the best compromise between price, range on batteries, and ability to drive long distances., but that doesn't exhibit any of the confusion about batteries vs fuel that you seemed to think you were responding to.
I imagine the people clicking the down facing triangle were responding to your unnecessary and out of place tone, not out of Tesla exuberance.
I imagine the people clicking the down facing triangle were responding to your unnecessary and out of place tone, not out of Tesla exuberance.
The free piston engine that is essentially a linear electric power generator in the OP is interesting and maybe promising for practice. And such a car with a battery for capturing energy from braking, operating accessories without the engine, and some extra power for a few seconds could be fine. Fine. I like it. Good OP.
You wrote:
> Nothing in the grandparent comment invites your first rant.
Wrong. From the OP I was responding to:
> Electrically driven cars are the future. But until we have cheap, 1000-mile batteries, we still need range-extending fossil-fuel engines.
This quote is the "rant" -- the writer hates "fossil-fuel engines" and is dreaming of "1000 mile batteries" presumably to be charged from the electric grid. Wacko nonsense. Smoking funny stuff nonsense.
Uh, just where would the energy to charge a "1000 mile battery" come from? Sure, now, heavily from the electric grid from fossil fuels. Wind, solar? Nope, not for the grid because those sources will need to store electric energy, and that's too darned expensive.
Some people just HATE a 15 gallon tank of gasoline or Diesel and just dream of "1000 mile batteries" and threaten to increase my costs of car travel and seriously weaken the US, and I don't like attacks on either me or the US.
This wacko, 'green worship' with humans and carbon as 'evil', etc. is going too darned far. I don't care about people worshiping the moon, but this wacko stuff is trying to hurt my car transportation, and I don't like it.
You wrote:
> Nothing in the grandparent comment invites your first rant.
Wrong. From the OP I was responding to:
> Electrically driven cars are the future. But until we have cheap, 1000-mile batteries, we still need range-extending fossil-fuel engines.
This quote is the "rant" -- the writer hates "fossil-fuel engines" and is dreaming of "1000 mile batteries" presumably to be charged from the electric grid. Wacko nonsense. Smoking funny stuff nonsense.
Uh, just where would the energy to charge a "1000 mile battery" come from? Sure, now, heavily from the electric grid from fossil fuels. Wind, solar? Nope, not for the grid because those sources will need to store electric energy, and that's too darned expensive.
Some people just HATE a 15 gallon tank of gasoline or Diesel and just dream of "1000 mile batteries" and threaten to increase my costs of car travel and seriously weaken the US, and I don't like attacks on either me or the US.
This wacko, 'green worship' with humans and carbon as 'evil', etc. is going too darned far. I don't care about people worshiping the moon, but this wacko stuff is trying to hurt my car transportation, and I don't like it.
Reconcile your impression with what they say here:
https://news.ycombinator.com/item?id=7977031
They also don't actually say the words you have put in quotation marks, or anything especially dreamy about electric cars. Maybe they said it somewhere else?
(I suppose 'less carbon' could be characterized as dreamy, but electric miles are often cheaper to operate, so I guess I don't like that characterization)
Anyway, I don't mind if you agree with me about whether the comment invites your response or not, I just wanted you to consider that maybe the people who inspired your second rant did understand your comment and downvoted for other reasons.
https://news.ycombinator.com/item?id=7977031
They also don't actually say the words you have put in quotation marks, or anything especially dreamy about electric cars. Maybe they said it somewhere else?
(I suppose 'less carbon' could be characterized as dreamy, but electric miles are often cheaper to operate, so I guess I don't like that characterization)
Anyway, I don't mind if you agree with me about whether the comment invites your response or not, I just wanted you to consider that maybe the people who inspired your second rant did understand your comment and downvoted for other reasons.
Ah, come ON.
The original post is the article
Jason Cammisa, "No crankshaft, no problem: Toyota's free piston engine is brilliant: Gas piston engine fundamentals haven't changed in 134 years—until now.", 'Road and Track', June 30, 2014.
at
http://www.roadandtrack.com/go/out-of-turn-toyota-engine
and the third paragraph starts with just what I quoted, exactly, again, yet again, one more time, exactly, precisely, every character right in place:
> Electrically driven cars are the future. But until we have cheap, 1000-mile batteries, we still need range-extending fossil-fuel engines.
Again, the work by Toyota looks good, and the article is somewhat interesting, but apparently the author wanted to insert a line to please the greenies so put in his "1000-mile batteries" and his swipe "fossil-fuel". Apparently with a little more encouragement he could have put in some words about evil humans and filthy CO2 and the dangers of 'global warming', rising sea levels, massive deaths of wildlife, the melting of Greenland, and 'climate change', that is, each tornado, hurricane, flood, drought, snow storm, especially hot/cold day, week, season, etc. I'm SICK of nearly constantly being beaten over the head for no good reason by this non-stop propaganda of total incompetent, made-up, hysterical, guilt-ridden, dysfunctional, destructive, dangerous nonsense.
This propaganda is trying to build a political consensus to get on my back and into my wallet and seriously hurt the US, and I don't like it.
I don't know who or what is paying for or pushing this propaganda, but I'm pushing back at it.
They also don't actually say the words you have put in quotation marks,
The original post is the article
Jason Cammisa, "No crankshaft, no problem: Toyota's free piston engine is brilliant: Gas piston engine fundamentals haven't changed in 134 years—until now.", 'Road and Track', June 30, 2014.
at
http://www.roadandtrack.com/go/out-of-turn-toyota-engine
and the third paragraph starts with just what I quoted, exactly, again, yet again, one more time, exactly, precisely, every character right in place:
> Electrically driven cars are the future. But until we have cheap, 1000-mile batteries, we still need range-extending fossil-fuel engines.
Again, the work by Toyota looks good, and the article is somewhat interesting, but apparently the author wanted to insert a line to please the greenies so put in his "1000-mile batteries" and his swipe "fossil-fuel". Apparently with a little more encouragement he could have put in some words about evil humans and filthy CO2 and the dangers of 'global warming', rising sea levels, massive deaths of wildlife, the melting of Greenland, and 'climate change', that is, each tornado, hurricane, flood, drought, snow storm, especially hot/cold day, week, season, etc. I'm SICK of nearly constantly being beaten over the head for no good reason by this non-stop propaganda of total incompetent, made-up, hysterical, guilt-ridden, dysfunctional, destructive, dangerous nonsense.
This propaganda is trying to build a political consensus to get on my back and into my wallet and seriously hurt the US, and I don't like it.
I don't know who or what is paying for or pushing this propaganda, but I'm pushing back at it.
They also don't actually say the words you have put in quotation marks,
Okay, I guess I misunderstood that your comment that was posted as a child of a comment was not actually a response to that post (I would guess that most other people made the same error...). Or are we supposed to tease out what part of the invective is directed at the parent comment and what part is directed at the overall story?
My bad substituting "carbon" for "CO2".
My bad substituting "carbon" for "CO2".
I didn't know the 'hierarchical' norm of implied references and, instead, thought that all the posts were about or at least in the context of the OP unless carefully stated otherwise.
For the guy with his Chevy Volt, fine.
For the guy with his Chevy Volt, fine.
I think if you are going to post a rant about the linked article, it's pretty appropriate to post it at top level, or at least as a reply to a comment with a lot of context.
I also think it would be more useful to post a thoughtful, persuasive comment (as opposed to saying 15 gallons multiple times), but that's a different issue.
Anyway, this whole sub thread is sort of unfortunate (in that we both wasted time and any unfortunate bystanders wasted their time too). Oh well.
I also think it would be more useful to post a thoughtful, persuasive comment (as opposed to saying 15 gallons multiple times), but that's a different issue.
Anyway, this whole sub thread is sort of unfortunate (in that we both wasted time and any unfortunate bystanders wasted their time too). Oh well.
I don't recall just why I posted just where I did in the tree, and I'm not going to waste any more time to look.
The 15 gallons thing is because I'm pissed at this greenie stuff and need to pound and pound on the rock solid, dirt simple, overwhelmingly important fact that the whole greenie thing is trying to beat a 15 gallon tank and has essentially no chance of doing so and, thus, is really dumb and much of why I'm pissed. I continue to be attacked here because of 15 gallons, and that shows again, yet again, once again, over again that even something as simple as a 15 gallon tank is unacceptable to the greenies so devoted they are to their irrational religion. The greenies can go worship the moon and I won't care, but they are a threat to my car and to the strength of the US, and I'm pissed, as nearly everyone in the US should be. This greenie stuff is wacko.
The 15 gallons thing is because I'm pissed at this greenie stuff and need to pound and pound on the rock solid, dirt simple, overwhelmingly important fact that the whole greenie thing is trying to beat a 15 gallon tank and has essentially no chance of doing so and, thus, is really dumb and much of why I'm pissed. I continue to be attacked here because of 15 gallons, and that shows again, yet again, once again, over again that even something as simple as a 15 gallon tank is unacceptable to the greenies so devoted they are to their irrational religion. The greenies can go worship the moon and I won't care, but they are a threat to my car and to the strength of the US, and I'm pissed, as nearly everyone in the US should be. This greenie stuff is wacko.
Yeah, I understand not wasting any more time on this thread.
You aren't getting attacked because you said 15 gallons though, people are down voting your posts because they don't add much to the conversation. You're imagining some motivated contingent of people voting against your posts because they speak the truth about the article, but really, your first post was down voted because it was somewhat obnoxious.
I mean, are you commenting here because it is a convenient place to propagandize, or are you commenting here because some decent and interesting conversations take place? If it's the latter, then you have a reason to make a better effort than making sure that your views get equal time propaganda. I realize that sounds preachy, but I'm too lazy to figure out how to better put it.
You aren't getting attacked because you said 15 gallons though, people are down voting your posts because they don't add much to the conversation. You're imagining some motivated contingent of people voting against your posts because they speak the truth about the article, but really, your first post was down voted because it was somewhat obnoxious.
I mean, are you commenting here because it is a convenient place to propagandize, or are you commenting here because some decent and interesting conversations take place? If it's the latter, then you have a reason to make a better effort than making sure that your views get equal time propaganda. I realize that sounds preachy, but I'm too lazy to figure out how to better put it.
> I only live 6 miles from work
Why'd you use a car then? That's a very nice bike ride. (I'm from The Netherlands so excuse my ignorance if there isn't even a physical way to bike around your area).
Why'd you use a car then? That's a very nice bike ride. (I'm from The Netherlands so excuse my ignorance if there isn't even a physical way to bike around your area).
> I believe this is what Chevy Volt does
The article's point is not to about "diesel-electric" systems (where the ICE acts solely as a prime mover for a generator and the wheels are always driven electrically). That's old news in both transportation in general (it's been in use in trains and ships since the early 20th century) and in hybrids ("diesel-electric" is sometimes called "series hybrid" or "range-extended electric vehicle" in cars).
It's about a new engine design[0] where electric generation is merged into the piston itself: a "normal" diesel-electric engine has a regular diesel engine (or more generally ICE) with pistons driving a crankshaft which drives the driveshaft, which is connected to a generator.
Here the design does away with the crank and driveshaft: the piston itself is a rotor, and the casing becomes the stator, doing away with mecanical transmission altogether: the piston and its cylinder become a linear generator.
[0] not quite that new, the first patent on free-piston engines[1] for linear generators dates back to 1959. The new part is getting a design to actually work in a vehicle[2].
[1] a free-piston engine is an engine without a crankshaft transforming the piston's linear movement into rotational movement
[2] the crankshaft does not just transform motion and lose energy, it also synchronises pistons and limits the piston's course. But if the piston+cylinder is a self-contained generator, I guess you can treat each piston as a single-piston linear engine? Which would limit the usual issues of multiple free-piston engines.
edit: formatting, footnotes
The article's point is not to about "diesel-electric" systems (where the ICE acts solely as a prime mover for a generator and the wheels are always driven electrically). That's old news in both transportation in general (it's been in use in trains and ships since the early 20th century) and in hybrids ("diesel-electric" is sometimes called "series hybrid" or "range-extended electric vehicle" in cars).
It's about a new engine design[0] where electric generation is merged into the piston itself: a "normal" diesel-electric engine has a regular diesel engine (or more generally ICE) with pistons driving a crankshaft which drives the driveshaft, which is connected to a generator.
Here the design does away with the crank and driveshaft: the piston itself is a rotor, and the casing becomes the stator, doing away with mecanical transmission altogether: the piston and its cylinder become a linear generator.
[0] not quite that new, the first patent on free-piston engines[1] for linear generators dates back to 1959. The new part is getting a design to actually work in a vehicle[2].
[1] a free-piston engine is an engine without a crankshaft transforming the piston's linear movement into rotational movement
[2] the crankshaft does not just transform motion and lose energy, it also synchronises pistons and limits the piston's course. But if the piston+cylinder is a self-contained generator, I guess you can treat each piston as a single-piston linear engine? Which would limit the usual issues of multiple free-piston engines.
edit: formatting, footnotes
Thanks for the explanation.
It's also a big deal having electronic controlled valves, you can make them have a square profile for maximum flow rates.
Why was this article removed from the front page of Hacker News?
Reminds me of http://en.wikipedia.org/wiki/Mazda_Wankel_engine
Good think this seems to be efficient, but I would like that instead they would be putting more focus on improving batteries rather than gas motors.
until you get most of your grid power from solar your still using fossil fuels for power.
About 30% of US electricity is produced from nuclear power or non-solar renewable sources. Solar may be a hot topic, but it's nowhere near being the top alternative to fossil fuels.
US =/= world. Solar is growing far far far quicker than nuclear.
Sure - but the grid + ev combo is still more efficient than a gas vehicle. And of course the grid uses a wide range of fossil fuels which reduces some of the geopolitical concerns. Finally in some places your power is already quite low on hydrocarbons - Seattle City Light is only 1.3% hydrocarbon.
95% of my grid power comes from hydro or nuclear, so I'm good.
sorry if your in the midwest...
Small engines are irrelevant to grid power regardless, even if you get all of your electricity from fossil fuels. Power plant generators are completely different beasts, as the tradeoffs change considerably as you scale up.
Wankel engines are great in some ways - but the seals are really difficult to get reliable.
Yeah, not like multi-billion dollar corporations can R&D into multiple areas at the same time.
Previous discussion: https://news.ycombinator.com/item?id=7677197
[deleted](1)
But today a 95% efficient generator connected to a 95% efficient motor for 90% overall transmission efficiency would be worth it on a turbine or Stirling engine running at 40-50% efficiency (maybe 40% overall at the wheels). Compare that with an old gas guzzler from the 70s running at 25% efficiency with maybe an 85% efficient transmission for 20% efficiency at the wheels. Not to mention that cars used to weigh twice as much which halved city fuel economy again, and lacked regenerative breaking which halved it again, and so on and so forth. It’s no wonder that cars used to get 10 mpg when what I would argue are relatively simple engineering changes could have raised that to 30, 50, even 100 mpg. It’s almost like they were deliberately designed to be as inefficient as possible…