Turbine-electric Jag accelerates like a jet

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In summary: I don't see any drawbacks that I can think of. Great idea, and it seems like it would work quite well.
  • #1
Astronuc
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Jaguar has new automobile design

Turbine-electric Jag accelerates like a jet


http://www.jaguar.com/us/en/#/about_jaguar/news_pr/cx75

- Capable of reaching 205mph (330km/h), sprinting from 0-62mph (100km/h) in just 3.4 seconds and blistering acceleration from 50-90mph (80-145km/h) in just 2.3 seconds

- Four powerful* 195bhp (145kW) electric motors – one for each wheel - produce 778bhp and an astonishing total torque output of 1,180lb ft (1,600Nm)

- Two micro gas-turbines, spinning at 80,000 rpm, can generate enough electricity to extend the range to a remarkable 560 miles (900 km); and produce just 28 grams of CO2 per kilometer from the car’s plug-in charge capability
Swoosh! :tongue2:
 
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  • #2
I saw this a few weeks ago and wondered why this hadn't been done before. I know that we have tried full-turbine cars before with. . . iffy results.

However, coupling a high efficiency gas turbine engine to an electrical drive just seems logical. We're basically changing our low efficiency otto-cycle motor for a much higher efficiency internal combustion engine.

Some good things:
- We have small gas turbine engines that currently operate in low-life (missiles), as well as high-life (UAV, etc).
- We can operate the gas turbine at peak efficiency level at [nearly] all times. This will let the engineers maximize performance per cost by not having to deal with off-design conditions.
- Smaller bill-of-materials means lowered costs; high volume parts could lower prices of superalloys (Inco, etc).

Some bad things I might see
- Man-rating the turbines could add weight (containment rings) and cost.
- Turbine-stage inspections could be more regular an oil changes.
- Potential for higher maintenance.
 
  • #3
The microgasturbines are manufactured by Bladon Jets.

http://mediajaguar.com/php/news.php?id=414 [Broken]
Propulsion system

The 330km/h (205mph) four-wheel drive supercar is capable of running in purely electric (zero tailpipe emissions) mode for 110km (68 miles) on a six-hour domestic plug-in charge. The innovative, lightweight micro gas-turbines are also capable of very quickly and efficiently recharging the Lithium-ion batteries, giving the car a theoretical range of 900km (560 miles).

This remarkable range-extension system is a result of Jaguar’s research engineers adopting a clean-sheet approach to the question of powering the supercars of the future. The C-X75 turns to the very latest evolution of a pioneering British technology: the gas turbine.

Developed in partnership with Bladon Jets, the miniaturised turbine blade - the first viable axial-flow micro-turbine - increases the compression and efficiency of micro gas-turbines to the point at which they can be viewed as a realistic power source. Each of the micro gas-turbines weighs just 35kg and produces 70kW of power at a constant 80,000rpm.

http://www.bladonjets.com/technology/
http://www.bladonjets.com/technology/gas-turbines/

This is interesting compared to automobile turbines I saw 20+ years ago. There was a program looking at Si3N4 turbine materials.
 
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  • #4
Astronuc said:
Turbine-electric Jag accelerates like a jet
Terrible title, particularly for that source: Jets have terrible acceleration for the horsepower they deliver. A turbine-electric hybrid could have excellent acceleration, though.




Looks to me like for at least a quarter mile [drag strip], the f1 car crushes the jet.
 
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  • #5
russ_watters said:
Looks to me like for at least a quarter mile [drag strip], the f1 car crushes the jet.

In '72, "Big Daddy" Don Garlits raced an A7E Corsair II on the deck of the USS Lexington with his top-fuel dragster, and in '83 took on an F-14 aboard the JFK. In both cases, the birds were assisted by the launch catapults, and in both cases the car won.
 
  • #6
I don't think in any way the developers are planning on using the turbines for thrust or propulsion. The idea is why use a 40% efficient engine when there are readily available engines which higher efficiencies and much fewer parts.

One more drawback I can see if noise. Small gas turbines general operate at very high speeds. Someone who doesn't maintain their vehicle could cause unbearable noise to people around him (bearing issues, etc).
 
  • #7
The noise from a gas turbine doesn't come from worn bearings. If there is a bearing problem it will fail (or rather, you hope the automatic control system will shut it down before it fails).

Small turbines are easier to silence than big ones, because the frequency content of the noise is higher so the silencing devices can be smaller. The reason why aircraft gas turbines are noisy is mostly to save weight. You can modifiy a Boeing 777-sized aircraft engine to drive a 50MW combined heat and power generation system, where weight is not a design constraint, and have a normal conversation standing beside it when it's running at full power.
 
  • #8
Two rather familiar names to me (Ruffles and Denton), on this page...
http://www.bladonjets.com/about/history/ [Broken] :cool:

This probably started out as a project to replace the small IC engine powered electrical generators with a turbine system (smaller, lighter, burns any fuel, etc). That didn't come to anything much, because a turbine in the 1 to 10 kW size range was too small to be cost effective engineering. I guess the way to fix that problem was make it 10 times bigger.
 
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  • #9
I'm certainly familiar with aerodynamic causes of noise in gas turbine engines; I know that if you're having journal bearing issues at 80k rpm, then you have issues. I was simply saying that there could be mechanical causes as well. Sure, there are many possible sources of 1 per rev noise generation, but there are also 1 per 2 rev sources as well.

One main reason for these having the potential to be quieter would be the nature of the engine. Essentially being a turboshaft, the engineer would not have to worry about screech tones coming from underexpanded nozzle flow.
 
  • #10
minger said:
Sure, there are many possible sources of 1 per rev noise generation, but there are also 1 per 2 rev sources as well.

"Oil less carbon-air bearing system" -- that should get rid of some of those :smile:
 
  • #11
Now that I've had a chance to read the links as well as just the thread, a couple of questions come to mind.
First off, I don't quite get what the exhaust vectoring is about. As far as that goes, I don't even know exactly what they mean about the CF rear diffuser. I'm pretty sure that it would be crystal clear with an illustration or two, but I'm not getting much from the text. I know that the latter has to do with undercarriage aerodynamics, and assume that they are using the venturi effect for downforce, but it is a little vague.
Secondly, is that a pencil shown in front of the turbine engine as a scale indicator? If so, I'm astounded to an extent that almost requires a change of trousers.

I love that car!
 
  • #12
Danger said:
Secondly, is that a pencil shown in front of the turbine engine as a scale indicator?

Have you seen http://www.jetcatusa.com? These are jets Yves Rossy used in his flying suit.
 
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  • #13
AlephZero said:
That didn't come to anything much, because a turbine in the 1 to 10 kW size range was too small to be cost effective engineering. I guess the way to fix that problem was make it 10 times bigger.

I think this is why you will never see turbine engines in the more "economic" type of hybrid cars. While the reduced maintenance is attractive, I don't think turbines will ever be cost effective. With the development of the Atkinson cycle and stratified charge engines the efficiency gap between the two gets rather small as well.
 
  • #14
Borek said:
Have you seen http://www.jetcatusa.com? These are jets Yves Rossy used in his flying suit.

Yeah, I read that site fairly extensively last year. Unless I'm missing something, though, these Bladon units are an order of magnitude more powerful for the same size.
 
  • #15
AlephZero said:
"Oil less carbon-air bearing system" -- that should get rid of some of those :smile:

Typical air bearings still require feed or some buffer cavity. Do a search on Wave Bearings. They're a lubeless air bearing which is a "seal-and-forget" configuration. They're pretty badass, and within a few years, I reckon will be in most small gas turbines.
 
  • #16
minger said:
I saw this a few weeks ago and wondered why this hadn't been done before. I know that we have tried full-turbine cars before with. . . iffy results.

Largely I expect because of this:
russ_watters said:
Terrible title, particularly for that source: Jets have terrible acceleration for the horsepower they deliver. A turbine-electric hybrid could have excellent acceleration, though.

Looks to me like for at least a quarter mile [drag strip], the f1 car crushes the jet.

That is, jet turbines take a long time to spool up to power; a problem pulling away from every stop. The electric motor - battery - turbine generator combo solves that problem.
 
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  • #17
The turbine electric combination seems to make a lot of sense, coupling the power density of the gas turbine with the power band of the electric motor. So I looked up turbine electric locomotives. These were experimented with a few decades back, but lost-out in favor of diesel electrics. I can't understand why. Anyone have a clue?

However I was inspired to discover which automobile had the greatest power to weight ratio. Its the Caparo T1, also British.

I've placed my order with Santa.

800px-Caparo_T1_British_International_Motorshow_2006_195999165.jpg
 
  • #18
I'm not sure about turbine-electric's, but you bring up an excellent point Phrak. Gas turbines excel when size limitations are removed. Many of the losses that we see in small gas turbines can be remedies or muted in large ones.

More to the point, ignoring the electric drive, why not just hook up an industrial power generation gas turbine to the train? Some of the "smaller" (I say smaller very loosely, haha) ones can be at operating condition in under 10-15 minutes. I can't imagine there is much of a weight issue between these and the ginormous diesel they currently use.

In this case, it seems locomotives are the perfect fit for one of these.
 
  • #19
Phrak said:
The turbine electric combination seems to make a lot of sense, coupling the power density of the gas turbine with the power band of the electric motor. So I looked up turbine electric locomotives. These were experimented with a few decades back, but lost-out in favor of diesel electrics. I can't understand why. Anyone have a clue?...
I speculate that in locomotives the superior power density of the turbine is secondary to the lower cost/HP of the nearly as efficient but heavier diesel.
 
  • #20
mheslep said:
I speculate that in locomotives the superior power density of the turbine is secondary to the lower cost/HP of the nearly as efficient but heavier diesel.

This is true. But if we are referring to the gas turbine electric locomotives used by Union Pacific around 50 years ago, efficiency was probably the main factor that did them in. Simply put, early gas turbines were horrendously inefficient (this fact also did ALOT to kill early gas turbine cars and give gas turbines in general a bad reputation for poor efficiency to this day). This was not originally a problem with these locomotives, since they could burn cheaper bunker fuel. But when the cost advantage of being able to use bunker fuel evaporated, gas turbine locomotives were no longer cost effective - at least with the highly inefficient turbines available at that time. Now that gas turbines are actually efficient, they are certainly more feasible. But the nagging issue of the cost of the turbine vs a diesel still exists. At this time, the most likely use of a gas turbine locomotive would be for high speed rail, where the lower weight and smaller size per HP would win out over the higher cost.
 
  • #21
StorminMatt said:
This is true. But if we are referring to the gas turbine electric locomotives used by Union Pacific around 50 years ago, efficiency was probably the main factor that did them in. Simply put, early gas turbines were horrendously inefficient (this fact also did ALOT to kill early gas turbine cars and give gas turbines in general a bad reputation for poor efficiency to this day). This was not originally a problem with these locomotives, since they could burn cheaper bunker fuel. But when the cost advantage of being able to use bunker fuel evaporated, gas turbine locomotives were no longer cost effective - at least with the highly inefficient turbines available at that time. Now that gas turbines are actually efficient, they are certainly more feasible. But the nagging issue of the cost of the turbine vs a diesel still exists.
Interesting history, thanks.

At this time, the most likely use of a gas turbine locomotive would be for high speed rail, where the lower weight and smaller size per HP would win out over the higher cost.
Yes, that does appear to be good place for the reappearance of turbine electrics. I know high speed rail has to be lighter than traditional heavy freight, though I don't know how much.
 
  • #22
I should sum this up by saying that, in the end, it is going to be COST that determines whether gas turbines will find their niche in land-based vehicles. In all other ways (maintenance, reliability, cost, efficiency, flex fuel capability, NVH, etc), current microturbines can better conventional piston engines. The problem is that there still isn't a small gas turbine available with less than a five figure price tag. Capstone Microturbines suggests that they could get the price of their 30KW model (a good size for a small plug-in hybrid) down to around $3000-$4000 through mass production. That would be nice. But I'll believe it when I see it. The Bladon Jets microturbine looks even better than the Capstone microturbine, since it utilized a more efficient axial flow design (vs the radial flow design of the Capstone turbines). But can they actually make the thing cheap enough to NOT give the average car buyer a SERIOUS case of sticker shock?
 
  • #23
StorminMatt said:
I should sum this up by saying that, in the end, it is going to be COST that determines whether gas turbines will find their niche in land-based vehicles. In all other ways (maintenance, reliability, cost, efficiency, flex fuel capability, NVH, etc), current microturbines can better conventional piston engines.
From what I know I agree with all those comparisons except cost. Micro-turbines can better reciprocating engines on cost? And then in this next part it you appear to argue against yourself on cost(?):
The problem is that there still isn't a small gas turbine available with less than a five figure price tag. Capstone Microturbines suggests that they could get the price of their 30KW model (a good size for a small plug-in hybrid) down to around $3000-$4000 through mass production. That would be nice. But I'll believe it when I see it. The Bladon Jets microturbine looks even better than the Capstone microturbine, since it utilized a more efficient axial flow design (vs the radial flow design of the Capstone turbines). But can they actually make the thing cheap enough to NOT give the average car buyer a SERIOUS case of sticker shock?
Yes, exactly, a 30KW(40HP) engine can be had for a few hundred dollars. How then are micro-turbines going to compete on cost? Are there other parts of a reciprocating engine system - radiator, fuel/oil pumps, exhaust system, etc - that would not be needed with a turbine system in a vehicle?
 
  • #24
Where does the high price come from for a turbine engine? I recall the high cost in labor required to grow single crystal tungsten blade blanks, then very slowly profiling one mil at a time with tungsten carbide bits, but that was ancient history, right?

Recalling a passing remark from the professor of a similarly ancient engineering materials class, I looked up silicon nitride and the first picture is a Si3N4 rotor. Oh, my. I'll have to read the article...

http://en.wikipedia.org/wiki/Silicon_nitride" [Broken]

And this article, from 1997, packed with an overwhelming amount of information,

http://www.unipass.com/predictionprobe/Industry%20News/Ceramics%20for%20turbine%20engines.htm"
 
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  • #25
Directionally solidified or even equiaxed cast turbine blades are extremely common now. Single crystal are still used, but only in high performance, high life situations (think aviation).

However, for long life applications, one would typically still almost need a cooled turbine blade. This lends itself to very expensive investment casting to get the cooling passages. Typically, at least for stage 1, expensive superalloys are needed as well. Your Si3N4 or aluminide type coatings are available, but also expensive.

Aside from that, there are almost niche parts like bearings which can completely wreck the cost of an engine. For much of the engine, typical high-strength steels can be used, so currently for a (relatively) low efficiency gas turbine, I'd say the issue is bearings, seals, and the hot section material.
 
  • #26
mheslep said:
From what I know I agree with all those comparisons except cost. Micro-turbines can better reciprocating engines on cost? And then in this next part it you appear to argue against yourself on cost(?):
Yes, exactly, a 30KW(40HP) engine can be had for a few hundred dollars. How then are micro-turbines going to compete on cost? Are there other parts of a reciprocating engine system - radiator, fuel/oil pumps, exhaust system, etc - that would not be needed with a turbine system in a vehicle?

My inclusion of cost in the list of advantages was, as you might guess, a mistake - just a simple oversight.

minger said:
Aside from that, there are almost niche parts like bearings which can completely wreck the cost of an engine. For much of the engine, typical high-strength steels can be used, so currently for a (relatively) low efficiency gas turbine, I'd say the issue is bearings, seals, and the hot section material.

Then again, if reducing costs means lowering the efficiency to the point that it is less efficient than a reciprocating engine, what's the point in using a gas turbine?
 
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  • #27
minger said:
Typical air bearings still require feed or some buffer cavity. Do a search on Wave Bearings. They're a lubeless air bearing which is a "seal-and-forget" configuration. They're pretty badass, and within a few years, I reckon will be in most small gas turbines.

How does wave bearings work? What is the difference between wave bearings and air bearings?
 
  • #28
GT1 said:
How does wave bearings work? What is the difference between wave bearings and air bearings?

I'm curious too. Every reference, so far I've seen, has been very cryptic, talking about the advantages of 'wave bearings' while never revealing what one is. --not a single, indirect hint about what is going on at the fluid or molecular level.
 
  • #29
minger said:
Directionally solidified or even equiaxed cast turbine blades are extremely common now. Single crystal are still used, but only in high performance, high life situations (think aviation).

However, for long life applications, one would typically still almost need a cooled turbine blade. This lends itself to very expensive investment casting to get the cooling passages. Typically, at least for stage 1, expensive superalloys are needed as well. Your Si3N4 or aluminide type coatings are available, but also expensive.

Aside from that, there are almost niche parts like bearings which can completely wreck the cost of an engine. For much of the engine, typical high-strength steels can be used, so currently for a (relatively) low efficiency gas turbine, I'd say the issue is bearings, seals, and the hot section material.

As far as I can tell, Si3N4 elements are exclusively manufactured by sintering. I was of the mind that it should be possible by this time to case it in bulk and work it via laser or plasma machining. But the stuff is not as wonderful as I'd hoped. It seems to be as brittle as glass, where surface scratches over 250 micron deep make it unacceptable for turbine blades. It's notable attraction seems to be it's high temperature stability.
 
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  • #30
Phrak said:
I'm curious too. Every reference, so far I've seen, has been very cryptic, talking about the advantages of 'wave bearings' while never revealing what one is. --not a single, indirect hint about what is going on at the fluid or molecular level.

There is a couple of papers out there that describe them; they should be by a guy named Dimofte (sp?). From what I understand, the unique profile on the journal produces a self-stabilizing hydrodynamic force.

They are still in testing phase, but could potentially be a huge improvement over buffer-supplied air bearings that are in use right now.
 
  • #31
Some references to Dimofte's work here:

http://www.grc.nasa.gov/WWW/RT/RT1996/5000/5340d.htm
 
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  • #32
Danger said:
Now that I've had a chance to read the links as well as just the thread, a couple of questions come to mind.
First off, I don't quite get what the exhaust vectoring is about. As far as that goes, I don't even know exactly what they mean about the CF rear diffuser. I'm pretty sure that it would be crystal clear with an illustration or two, but I'm not getting much from the text. I know that the latter has to do with undercarriage aerodynamics, and assume that they are using the venturi effect for downforce, but it is a little vague.
Secondly, is that a pencil shown in front of the turbine engine as a scale indicator? If so, I'm astounded to an extent that almost requires a change of trousers.

I love that car!

It's one of the features that helps feed air to the turbines.
 
  • #33
Thanks, Husker.
 
  • #34
minger said:
There is a couple of papers out there that describe them; they should be by a guy named Dimofte (sp?). From what I understand, the unique profile on the journal produces a self-stabilizing hydrodynamic force.

They are still in testing phase, but could potentially be a huge improvement over buffer-supplied air bearings that are in use right now.

Air bearings that do not require buffer air (any gas) are technically called self-acting, hydrodynamic or aerodynamic and there are a multitude of mechanisms that are used to stabilise them. Waves or lobed air/gas bearings have been used for many years starting with the circulating pumps in nuclear power plants in the 1960s. Other mechanisms to stabilise them are steps or spiral grooves (do a search for spiral groove air bearings) sometimes called herringbone grooves in journal bearings. Smiths Industries and Ferrantis had many thousands of this latter type in gyroscopes in the 60s, 70s and 80s. As with many technologies changing the name slightly allows an application for research funding!
All these self-acting air bearing designs with a rigid surface have significant advantages over the foil type air bearing due to their better control of radial and axial position; and this is why one is seeing more and more applications using air/gas bearings.
 

1. How does the turbine-electric Jag accelerate like a jet?

The turbine-electric Jag uses a combination of a gas turbine engine and electric motors to produce high levels of torque and power, similar to that of a jet engine. This allows for rapid acceleration and impressive performance.

2. What is a gas turbine engine?

A gas turbine engine is a type of internal combustion engine that uses hot gas produced by burning fuel to drive a turbine, which in turn powers a compressor to generate thrust. It is commonly used in aircraft and power plants.

3. How does the electric motor contribute to the acceleration?

The electric motor in the turbine-electric Jag provides instant torque, allowing for quick acceleration from a standstill. It also works in conjunction with the gas turbine engine to provide additional power and efficiency.

4. Is the turbine-electric Jag more environmentally friendly than traditional combustion engines?

Yes, the turbine-electric Jag produces significantly lower emissions compared to traditional combustion engines. The use of electric motors also reduces the reliance on fossil fuels, making it a more sustainable option.

5. What makes the turbine-electric Jag different from other electric cars?

The turbine-electric Jag is unique in that it combines the power and performance of a gas turbine engine with the efficiency and sustainability of electric motors. It also has a longer range compared to other electric cars, making it a more practical option for long-distance travel.

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