Rode an electric bike today

[reemit]

beep.... primitive earthdwellers.... beep.

[R-Soul]

and what about a bike that burns diesel, or methane, or petrol, or alcohol, or whaterver all with same engine, and that goes from a minimum of 20-25 to a maximum of 200-250 km per liter of diesel?
electric, with "generous" performance and acting as a platform for quick conversion as batteries tech steps forward. available today.
well, in a year...

So what engine are you talking about here then?

[Urano]

a turbine.
obviously.
what am i a pilot for?

[R-Soul]

a turbine.
obviously.
what am i a pilot for?

Sure, but then you have heat dissipation problems (or alternatively low efficiency if you have low heat), expensive material requirements, and hiogh wear.

[Urano]

heat?
you mean from the exhaust?
not at all... you USE the heat and pressure drop to make the turbine run. modern fan engines have core exhaust temperature not much more than 300-400 °C, which can be still lowered if you don't need residual thrust at all, and the thermal emission can generate current directly for the richardson law (the inverse of joule effect...).
at the end you have a thermal residual which is not so much more than a normal reciprocating engine, and way less than some fuel cell.

about the expensive materials... yep, it's surely more critic than a cast iron carter, but not so much more than high technology fuel cells or exotic material batteries...
and for the high wear, well, turbine engines have service interval larger than normal 4 stroke bike engines as for hour of use.

donno, there are obviously large margins of improvement and refinement, but at least we KNOW that it works: it works everyday in planes' apu, it works everyday in any modern vessel...
it's already developed and studied, we know the problems and the solutions...
other configurations as sterling, wankel, miller or atkinson at today time are blind jumps...

[bogan]

heat?
you mean from the exhaust?
not at all... you USE the heat and pressure drop to make the turbine run. modern fan engines have core exhaust temperature not much more than 300-400 °C, which can be still lowered if you don't need residual thrust at all, and the thermal emission can generate current directly for the richardson law (the inverse of joule effect...).
at the end you have a thermal residual which is not so much more than a normal reciprocating engine, and way less than some fuel cell.

about the expensive materials... yep, it's surely more critic than a cast iron carter, but not so much more than high technology fuel cells or exotic material batteries...
and for the high wear, well, turbine engines have service interval larger than normal 4 stroke bike engines as for hour of use.

donno, there are obviously large margins of improvement and refinement, but at least we KNOW that it works: it works everyday in planes' apu, it works everyday in any modern vessel...
it's already developed and studied, we know the problems and the solutions...
other configurations as sterling, wankel, miller or atkinson at today time are blind jumps...

thats the thing, we know it works, it's been around for ages, yet it hasn't replaced four strokes yet, why not?

[Urano]

investment and marketing.
it has replaced the reciprocating engines everywhere efficiency and cost effectiveness are more interesting than commercial solutions.

you have a thing that works properly after 50-60 years of developing. the performance are sufficient, factory costs are plained, at the same time you have mounting costs on other side as safety and electronics, why oh why should you put your effort to find something else and make it works, stated that you are selling so well what you already have and there are even parts of customer base that DON'T WANT something different?

on planes and boats things are different. planes and large vessel are mostly sold to companies, not individuals, and companies are more interested in efficiency and performance than "the sound of the exhaust".

with bikes the things are even more complex. nowadays when you buy a car you have a vague interest on how much does it go with a liter of petrol. how many bikers ask for fuel consumption before buying a bike? i don't know in nz, but here in italy almost nobody.
they want the noise, the creepy power, the vibration, the reassuring knowledge that behind the tank nothing different than what they so well know is happening...

with bikes there is a so big emotional part, and that is one of the main wrong thing the proposal of a bike that makes no noise, no vibration, and have a "on-off" idea of riding.
here you come with a sterling or a miller: you have less cv, but it's more efficient.
and the biker says: "LESS CVs???????"
"but it's more efficient!"
"LESSSS CVs??????????"
"but... well, nevermind..."


come with a turbine instead.
"here it is, something that consumes fuel on hour and not on kms, and it's more efficient!"
"uhm... nothing going up and down?"
"nope, but is the same technology of a fighter jet!! do you hear the top gun noise and the red blinking lights??!!"
"OH YEAH! IT'S FUCKIN AWSOME!!!! give me three of that!"

and that's the way the world goes...

[bogan]

come with a turbine instead.
"here it is, something that consumes fuel on hour and not on kms, and it's more efficient!"

what the? how does something consume fuel on hours not kms? the more km/hr you go, the more energy is required. I think you need to go back to basics with the whole energy and efficiency thing, also post up some figure to back your claims that turbines are more efficient than four strokes.

[Urano]

nope...
the turbine has to go always at the same rpm at his max efficiency rotation, and connected to the generator charge the batteries.
then the batteries feed the electric engine that run the bike.
the turbine consumes always the same on hourly basis, so if you have a 1 l/hr consumption and you are going at 15 km/h you'll have a 15 km/l of consumption.
but if you are going at 100 km/h you'll get 100 km/l.
average speed in cities for cars is nowadays about 20-30 km/h, bikes do something more. so is not illogical expecting a maximum consumption of 20-30 km/h, with the possibilities of going down to 100-120 km/l
then actually a 1 l/h of consumtion is very low, it could be possible for a very small turbine, but a twice one is still acceptable, and don't forget the possibilities of using different fuels with little adjustments...

all the apus work this way...

[R-Soul]

heat?
you mean from the exhaust?
not at all... you USE the heat and pressure drop to make the turbine run. modern fan engines have core exhaust temperature not much more than 300-400 °C, which can be still lowered if you don't need residual thrust at all, and the thermal emission can generate current directly for the richardson law (the inverse of joule effect...).
at the end you have a thermal residual which is not so much more than a normal reciprocating engine, and way less than some fuel cell.

about the expensive materials... yep, it's surely more critic than a cast iron carter, but not so much more than high technology fuel cells or exotic material batteries...
and for the high wear, well, turbine engines have service interval larger than normal 4 stroke bike engines as for hour of use.

donno, there are obviously large margins of improvement and refinement, but at least we KNOW that it works: it works everyday in planes' apu, it works everyday in any modern vessel...
it's already developed and studied, we know the problems and the solutions...
other configurations as sterling, wankel, miller or atkinson at today time are blind jumps...

Nope sterling is not a blind jump. It is avery simple piston engine with known, developed (enough) piston tech, slow speeds, and made of simple cheap materials. It burns anything - even leaves and coal (try put those in a turbine!) - and provides high efficiency combustion, and high efficiency thermodynamic cycle.

No fancy materials - except in the batteries- which your proposal will use too.

(And TBH - only a subjective thing of course - I would be a little nervous sitting on top of something rotation at 30,000 rpm, on the odd chance that things do go wrong...)

[R-Soul]

investment and marketing.
it has replaced the reciprocating engines everywhere efficiency and cost effectiveness are more interesting than commercial solutions.

........
on planes and boats things are different. planes and large vessel are mostly sold to companies, not individuals, and companies are more interested in efficiency and performance than "the sound of the exhaust".

Actually they have replaced IC engines only in situations where other features are required.
In planes, it is their ability to work at high altitude with low oxygen levels.

In racing (and tanks - the Abrahams M1) because they offer a higher power to weight ratio. Notice, however, that trucking and haulage has stayed with diesel. So have the ultimate efficiency people - the shipping people. If turbines offered them efficiency gains, together with reliability and cost to buy, they would be on it like a shot. But turbines are found in luxury superyachts, because the owners of these are not so worried about efficency, or even relaibility.

Granted, power stations use turbines, because they are efficient when high temperatures are available, but they expect a massive capital outlay for it. And have very strict maintenance regimes.

Even if the effiecncies are higher thermodynamically (which they may be if set out right), the materials required to sustain 30k rpm for long times periods are very specialised, and the only reason why service intervals could be "higher in hours than IC engines" is because they have those materials. Not even so long ago, turbochargers on cars were failing because they just wore out so quickly at high speeds with unspecialised materials (i.e plain old steel).

The efficiency of turbines are also directly related to temperature difference. So effectively, the higher the temperature in the engine, the better the efficiency. For really efficent turbines, you need to have really high temps - and again really specialised materials.
The titanium-aluminium alloys used in aerospce engines are ridiculously specialised.

with bikes there is a so big emotional part, and that is one of the main wrong thing the proposal of a bike that makes no noise, no vibration, and have a "on-off" idea of riding.
here you come with a sterling or a miller: you have less cv, but it's more efficient.
and the biker says: "LESS CVs???????"
"but it's more efficient!"
"LESSSS CVs??????????"
"but... well, nevermind..."


come with a turbine instead.
"here it is, something that consumes fuel on hour and not on kms, and it's more efficient!"
"uhm... nothing going up and down?"
"nope, but is the same technology of a fighter jet!! do you hear the top gun noise and the red blinking lights??!!"
"OH YEAH! IT'S FUCKIN AWSOME!!!! give me three of that!"

and that's the way the world goes...

You are probably right there LOL!
Mind you I think it would be intriguieing to ride at speed silently. I went on a trip in a tandem glider - no engine. The sheers silence of it was exhilarating! Not quite like biking I know...

[bogan]

nope...
the turbine has to go always at the same rpm at his max efficiency rotation, and connected to the generator charge the batteries.
then the batteries feed the electric engine that run the bike.
the turbine consumes always the same on hourly basis, so if you have a 1 l/hr consumption and you are going at 15 km/h you'll have a 15 km/l of consumption.
but if you are going at 100 km/h you'll get 100 km/l.
average speed in cities for cars is nowadays about 20-30 km/h, bikes do something more. so is not illogical expecting a maximum consumption of 20-30 km/h, with the possibilities of going down to 100-120 km/l
then actually a 1 l/h of consumtion is very low, it could be possible for a very small turbine, but a twice one is still acceptable, and don't forget the possibilities of using different fuels with little adjustments...

all the apus work this way...

so basically you are saying that the turbine is always run at a set speed with a set amount of fuel consumption? What is the efficiency of the engine when it is running like that? (referenced please) cos if it isn't fucking amazing, it blows your theory out of the water.

[Urano]

Nope sterling is not a blind jump. It is avery simple piston engine with known, developed (enough) piston tech, slow speeds, and made of simple cheap materials. It burns anything - even leaves and coal (try put those in a turbine!) - and provides high efficiency combustion, and high efficiency thermodynamic cycle.
No fancy materials - except in the batteries- which your proposal will use too.

all true.
i don't agree only with the "high efficiency combustion" part. the sterling has an high efficiency in transforming the heat provided in motion, but the combustion efficiency can be high or low, independently by the rest of the engine...

I would be a little nervous sitting on top of something rotation at 30,000 rpm, on the odd chance that things do go wrong...)

LOL...
remember it when you decide to put yourself inside a metal condom pumped with air kept at 10 km high by two o more barely contained conflagrations...
once i was in the cockpit of a md11 in the middle of atlantic at fl390, and suddenly realized that under my feet there was about 1 meter and a half of metal, then 12 km of nothing...what a dive!

Actually they have replaced IC engines only in situations where other features are required.
In planes, it is their ability to work at high altitude with low oxygen levels.

yes, but flying at high altitudes is a bag of hurt.
everybody would be more than happy to fly at 3000 ft.
if you want to fly at fl 410 you have problems to keep persons alive, to keep the structure together, to keep the temperatures controlled, to fight winds at 360 kmh, to resist to severe turbolence, all the problems to go up there and to come back home in one piece.
everything is made for one reason only: efficiency.
a turbine consumption is much less at high altitudes and with 55° subzero exactly because, as you said, the pressure and temperature jump is much higher (then you have other aspects as ram and temperature raise...whatever...)
this reason is so much important that long range cruises are usually made keeping the balance, the equilibrium, between the risk to fall because you are going to slow and to fall because you are going to fast (the so called "buffet onset"): this thin region of safe flight is thins as you climb reaching a "cuspid". you'll can climb further only when you'll weight less cause of fuel consumption.
and keep fuel consumption low is the only way to reach brazil from europe without stopping to refuel at salt island in the middle of atlantic.
so, as you see, flying high is not the reason: speed and efficiency are the reasons, flying high is an extremely difficult consequence...

But turbines are found in luxury superyachts, because the owners of these are not so worried about efficency, or even relaibility.

actually, taking about vessels, i was not referring to yacht.
but to stuff like these:
http://en.wikipedia.org/wiki/RMS_Queen_Mary_2
http://en.wikipedia.org/wiki/Type_45_destroyer
http://en.wikipedia.org/wiki/SS_Canberra
http://en.wikipedia.org/wiki/Disney_Magic
and many others...

nowadays is the normal design: electrical driven propeller, without shaft passing the hull (or very short shafts anyway), with electrical power always on provided with turbines or diesel/turbines, as little electrical plants...
(maybe "vessel" is not the right word: sorry about my poor lexical choices...)

so basically you are saying that the turbine is always run at a set speed with a set amount of fuel consumption? What is the efficiency of the engine when it is running like that? (referenced please) cos if it isn't fucking amazing, it blows your theory out of the water.

it's fucking amazing.
goes from 35 to 65 % depending on the use and specialization.
wikipedia can give you a gross (and not perfectly exact) idea here: http://en.wikipedia.org/wiki/File:GFImg7.png
consider that petrol bikes' engines have efficiency of 25% average, best petrol engines come up to 35% maximum.
diesel do better. with an average of 35% up to 40%, but should be used at idle only, even if modern turbo diesel (being disconnected by stoichiometric needs ps:thanks google translator ) can go higher, to around 45%.

the problem is, for bikes and cars, that turbines are so efficient but at high rpm only.
so the concept is to completely disconnect their revving by the needs of the pilot: they have to serve the needs of the batteries. only. you need speed but the batteries are full because you've charged them all night at home? it stays off. you are slowing down but the batteries are low? the turbine goes at maximum to charge efficiently...

that the concept.
not saying it couldn't be refined or improved, but this works, right now. it can be working on your bike. you can choose to go to the dairy within 10 km from home electrical only, or you can go further relaying on your little turbo generator without the fear of 6 hours of charge needed to come back home...
give it a centesimal of the effort fiat put on that shit of multiair, and the world would change.

[Urano]

this post duplication is becoming pretty annoying....

[bogan]

it's fucking amazing.
goes from 35 to 65 % depending on the use and specialization.
wikipedia can give you a gross (and not perfectly exact) idea here: http://en.wikipedia.org/wiki/File:GFImg7.png
consider that petrol bikes' engines have efficiency of 25% average, best petrol engines come up to 35% maximum.
diesel do better. with an average of 35% up to 40%, but should be used at idle only, even if modern turbo diesel (being disconnected by stoichiometric needs ps:thanks google translator ) can go higher, to around 45%.

the problem is, for bikes and cars, that turbines are so efficient but at high rpm only.
so the concept is to completely disconnect their revving by the needs of the pilot: they have to serve the needs of the batteries. only. you need speed but the batteries are full because you've charged them all night at home? it stays off. you are slowing down but the batteries are low? the turbine goes at maximum to charge efficiently...

that the concept.
not saying it couldn't be refined or improved, but this works, right now. it can be working on your bike. you can choose to go to the dairy within 10 km from home electrical only, or you can go further relaying on your little turbo generator without the fear of 6 hours of charge needed to come back home...
give it a centesimal of the effort fiat put on that shit of multiair, and the world would change.

ok, now we're getting somewhere but to compare apples with apples, you need to find the efficiency of the smallest turbine you can find, as generally large engines are more efficient. Also the Otto cycle is around 35% efficient, the 25% average is due to emission controls and regulations, would a turbine have problems with emissions laws?

Another point to consider is system losses, you may get 60% at the turbine output shaft, but then you need a generator, BMS, and electric motor. Even if each of those is 90% efficient you have just dropped the system efficiency down to 43% which is only a 25% efficiency gain over the otto cycle. And good luck finding the components listed above with efficiency that high!

Then there's the manufacturing costs of the high spec components needed in the vehicle, and the increased emissions associated with that (apparently its far more energy efficient just to keep an old car on the road than buy a new one). Seems a far better idea to take the generator bits off the vehicle, leave the battery and electric motor and charge from mains then use universal batterys that can be swapped for full ones at fuel stations.