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GM Working on Feasible Electric Car
WindBourne writes "While Ford wants to simply offer cosmetic changes to automobiles interiors and exteriors, General Motors has finally gotten the message about electric autos. They are about to introduce the Chevy Volt, a plug-in hybrid which gets 40 Miles on a charge, but has a generator that can keep the auto going up to 640 miles range. From a styling POV, it is not a tesla, but it is also not a focus or a pinto. From the Rocky article: 'GM did not release cost estimates but said they recognize the Volt's price will have to be competitive. Company Vice Chairman Robert Lutz said in a statement that more than half of Americans live less than 20 miles from their workplace and could go to work and back on a single charge.'"
Also coming from GM in model year 2008 is the full hybrid GMT900 truck platform [1, 2, . This encompasses the Chevy Tahoe and Suburban, the GMC Yukon and Yukon XL, and the Cadillac Escalade and Escalade ESV, among others. The hybrid uses the GM/DaimlerChrysler Advanced Hybrid System 2.
The hybrids will feature:
- 5.3L FlexFuel Vortec V8 (able to run using E85, a blend of 85% ethanol and 15% gasoline)
- Active Fuel Management (AFM)/Displacement on Demand (DOD), disabling cylinders as needed for cruising
- Two 30kW electric motors inside of the same physical space as the normal automatic transmission
- A continuously variable automatic transmission
- Conventional 110VAC power outlets on board
- Hybrid system derived from the advanced system on already in use on GM's Allison transit buses
This advanced hybrid system, while not plug-in, will be offered on all model year 2008 GM full size SUVs, as well as pickups and fleet vehicles. The expected fuel economy gain is 30% over today's figures on the gasoline/FlexFuel-only AFM variant, approaching 30mpg for city driving. That's a damned good improvement. And when used with FlexFuel, they're using less fossil fuels - even including the fully burdened fossil fuel costs of ethanol - than Prius and Civic hybrid drivers, in addition to contributing to lower overall greenhouse gas emissions. As the process efficiency increases over the next few years, these numbers will improve.
Whether or not one likes or dislikes SUVs, or thinks people should be able to be told what types of vehicles they should or shouldn't be driving, or think subjective judgments can be simplistically made about what other people "need" or don't need, it's still an excellent step forward. While the Volt is very interesting (conspiracy theorists: think of some way the Volt is really still a GM plot to "keep electric vehicles down" or to assist big oil) and using centralized power generation and leveraging the existing electric grid and production capacity is a necessary step to the future, the full hybrid SUVs will be one of the big things that people buy in the short term, not to mention being one of the major things - if not the thing - that may make or break GM in the next decade.
Who Ignored the Facts About the Electric Car?
GM's EV1 -- Who Killed Common Sense?
GM officials stressed that development of the battery pack is critical to the concept vehicle reaching showrooms, and the technology likely won't be available until 2010 or 2012.
So it's due in 3 to 5 years - assuming GM doesn't change its commitment to the project, and that the battery pack development goes as well as it's hoped to.
So how can Tesla, a startup company with little manufacturing and car experience relative to GM, build an electric car that can make it 200 miles on a charge
The Tesla's sticker price of $92,500 makes it possible.
We're making progress, though. The only real remaining problem with high performance electric cars is battery cost. The necessary energy density is available if you pay enough.
http://www.cbsnews.com/stories/2006/06/18/ap/busin ess/mainD8IASIGO1.shtml
The above link is an example of the serious work being done to make coal power environmentally friendly. The plant in the article won't even emit CO2. Modern coal plants (which are already very efficient), nuclear, hydro and wind power make an electric car much friendlier to the environment than gas. Of course the batteries are a bit ugly but , if such cars become common, they will be efficiently recycled.
Is this actually true? I would like to ask Mr. Lutz for a cite or three to back this assertion.
It seems reasonable at first blush, after all, unless you just LOVE sitting in your car idling down the freeway for hours a day, you probably want to live somewhere close to work. The average distance from home to work in Los Angeles is 8.2 miles (pdf), which includes claims that this is "consistent" with census data (except that it looks like the Census doesn't report distance, they report travel time) and compares with other metropolitan areas. This (another pdf) says that the average first job for people going off welfare is 6.5 miles away. This PDF claims that work causes people to drive an average of 12 miles per day. This site says that over 1/3 of workers in the 100 largest cities drive more than 10 miles to work.
If I have been able to see further than others, it is because I bought a pair of binoculars.
Don't know yet, but given that the 2007 North American International Auto Show is this week, we might be hearing more. And given that these will all be available for model year 2008, which will occur mid to late calendar year 2007, we'll have to hear something about price pretty soon. GM knows it has to be cost-competitive. And, frankly, buyers need to know that spending a little more up front will be better for everything from the environment, to fossil fuel foreign policy, to their pocketbooks. But even though compact fluorescents are provably less expensive over their lifetime than incandescents, it's still tough to convince people to change.
Actually the range for the Volt is 600 miles, not 40 due to the generator. The build cost for that is more reasonable than 5x the batteries, and allows for longer trips. It looks like a smart idea. The electric portion of the car can be generic, while the generator could be gas, diesel, biodiesel, hydrogen or fuel cell. I doubt GM's plan is to sell the car for $100K
Going longer on batteries is nice, but not everyone would agree that going a big further per charge is worth it if it reduces the ability for actual long distance driving. Some people have resorted to pulling trailers with generators for "pure" electric cars for long trips, so this is a much tidier solution. A car only useful for short trips would work for some people, but one that can directly replace an existing car where you don't have to worry about where the next charging location is will have much greater appeal.
Depending on the length of the cable run, up to 50% of the electricity is lost
Not even close.
Transmission and distribution losses in the USA were estimated at 7.2% in 1995 [2], and in the UK at 7.4% in 1998. [3]
You can never go home again... but I guess you can shop there.
While Ford wants to simply offer cosmetic changes to automobiles interiors and exteriors
= /20060104/FREE/60103014/1115
Ford is showing a 65mpg diesel hybrid - with supplemental solar power, no less. I'm not sure why 50mpg hybrids from GM are a revelation but a 65mpg diesel hybrid from Ford is "cosmetic", but there you go.
http://www.autonews.com/apps/pbcs.dll/article?AID
It may not be the best solution for the USA, but still, you do have to admit it should be easier to filter all the pollution at power plants than in millions of cars.
Here in Quebec and Ontario, with all our hydro-electricity, electric cars really would be "clean cars" (or at least incredibly more clean than fossil fuel cars).
They don't have to. The idea is you have a turbine that can be switched on or off to charge the batteries. This turbine is in no way hooked to the drive train. The car then runs purly in electrical mode all the time. The turbine can be run at peak efficiency.
And yes running all electric this way is actually very efficient, several modders have disconnected the drive train on their prius and showed gas miliage improvements.
In much of Europe we've got this kind of thing for a long while already. For example, in Norway you pay taxes on a new vehicle according to weigth, engine-volume and horsepower (though it's recently been suggested to replace this with CO2-emmision/km). In Germany you pay a yearly "road-tax" that is scaled by the volume of your engine and the emission-class of the vehicle. (i.e. a car that pollutes less will pay a lower tax)
There, fixed that for you.
What's the point of linking to an ugly fuzzy pixelated scanned newspaper photo when the Chevy site has a beautiful photo and lots of information about the car?
http://www.chevrolet.com/electriccar/index.jsp
I think you're picking nits. . .
.from my perspective those other cars ARE hybrids. . .
No. I am speaking of fundamental and critical differences.
. .
I am speaking from the perspective of a designer of electric and hybrid cars; who has some knowledge of the history of the things back into the 19th century.
They are not true hybrids. They are multi-drive source. There is a huge difference, but I might need to sit you down with a pile of drawings/models to make it clear.
The Volt is an electric car... that just happens to carry around it's own backup generator.
You are not quite there, but you have just come damned close to the actual definition of the Combustion/Electric hybrid car.
The Combustion/Hybrid is one that burns fuel to operate a heat engine, but uses the heat engine to turn a generator, not the wheels. The heat engine of a true hyrid is not connected to the drive train at all. The electric motor alone is. Since even when operating as an electric it relies on the burning of fuel as its primary energy source there is no need for the combustion motor to provide drive.
This has, dare I say it, "paradigm shifting" implications. I've covered most of them in years past. I've been extremely ill the past few days; at deaths door and shit, I wasn't even supposed to be here today and I just don't have the energy right now to tread over old ground on a serious technical subject.
So I'm afraid I'm just going to state it as fact and abandon.
KFG
I really doubt it. Why?
* Prius and Civic hybrids get 55 and 50 MPG combined, respectively. The 2007 Yukon XL 1500 2WD gets 15/21 gas, 12/16 ethanol. The 2007 Suburban 1500 2WD gets 15/21 gas, 12/16 ethanol. Even give 'em 30% gain and they're nowhere near Prius and Civic.
* As for the petroleum content of American made ethanol: given that petroleum is used all over the refining process (from fertilizer to transportation), and given that a gallon of gasoline has 124,000 BTU of energy but the net gain in a gallon of ethanol is a mere 20,000 to 40,000 BTU you get to use 6 gallons of E100 for the fossil fuel cost of 3 to 5 gallons of E0 (gasoline). Let's use the 40,000 BTU number: by using ethanol you can use 4 gallons at the "carbon gasoline cost" of 3 gallons of gas.
So, lets do the math: 30% fuel efficiency gain on 15/21 (we'll pretend that we should be working off of their gasoline and not ethanol numbers) gets us to 19.5/27.3. But, don't forget about the "4 for the cost of 3" -- so the carbon release would be equivalent to a car that gets 26/36.4. Now, sure this is back of the envelope, but I've been really generous -- giving the full 30% on the gasoline numbers (not the ethanol numbers), and giving the very highest estimate for BTU increase.
We're still at 26/36.4 mpg for the GM SUVs vs 50 or 55 mpg for the Civic and Prius hybrids. You're still off by a factor of 2, sport.
I hope this isn't more GM vaporware. I hope this stuff works, and sells. I hope ethanol improvements increase that 40,000 BTU gain. I hope the 30% efficiency gains are just the beginning.
But even with those gains, (telecommute / walk / bike) > (bus / train / subway / carpool) > (high mpg) > (mid mpg) > (SUV) in terms of mpg, roughly speaking.
Support a few technologists in Washington.
Something the parent poster may have been getting at is that turbines tend to be rather loud at speed, have to dump a lot of waste heat, and having parts spinning around a thousand times per second in your car may prove to be a safety issue. That's not to say that a workable turbine design couldn't be done, just that there are some formidable engineering challenges to be met.
Please stand clear of the doors, por favor mantenganse alejado de las puertas
Don't forget there's also the question of 'Who has the most to gain?'. If you think about it a moment, you realize that SUVs, being larger vehicles than a car, stand to save a larger amount of gasoline than a small car. Going from 12mpg to 30 mpg will save more gasoline than 30 to 40 mpg. The larger vehicle also has more space to put the necessary equipment because many of the parts will be about the same size whether it's in a Honda civic or Ford Escape. Oh, and electric motors tend to be more efficient the larger they are, so you can gain a few percentage points there. Add in the systems end up costing less as a percentage of the cost of the vehicle as a whole, and I wonder why they didn't come out with hybrid SUVs sooner.
Basically, it actually makes more sense to put hybrid systems into SUV's than compact cars. It's part of the reason that locomotives have been effectivly hybrids for years(major reason is the elimination of the transmission, of course).
I don't read AC A human right
Unfortunately, it's true for most of the rest of the western world - indeed, most of the rest of the world - as well.
Despite all the hydro in e.g. Canada & China, nuclear in e.g. the US & Europe, & natural gas in e.g. Africa & the subcontinent, burning coal is the primary source of electrical energy in the world today by a large margin.
What part of "a well regulated militia" do you not understand?
UK electricity generation by fuel: Nat Gas 38.7%, Coal 33.6% (source)
Total world electric generation by fuel: Coal 39.8%, Nat Gas 19.6% , Hyrdo 16.1%, Nuke 15.7%, Oil 6.7% (source)
Nations with high reliance on coal for electric generation (2005 unless stated): Poland 92%, South Africa 92% (2004), Australia 79% (or 85+%), China 78% (2004), Israel 75% (2004), Kazakhstan 70% (2004), India 69% (2004), Morocco 67% (2004), Czech Republic 61%, Greece 59%, USA 50%, Germany 49%
...not to mention that every mechanic in the country would have to learn how to work on a fundamentally different type of power plant.
my sig's at the bottom of the page.
The cost of roads comes from the fuel tax. And no matter how you look at it, the government subsidy of mass transit (on a per passenger per mile basis) is at least 2.5 times that of roads.
If transit users had to pay an equal amount (taking subsidies into account) that $2 bus fare would be more like $5-$8.
If you have doubts refer to:
Gomez-Ibanez, J. (1997). Estimating Whether Transport Users Pay Their Way: The State of the Art. In Greene, D.L., Jones, D.W. & Delucchi, M.A. (Eds.) "The Full Costs and Benefits of Transportation (pp. 149-172). New-York: Springer Verlag.
The Tesla is built on a Lotus Elise. The Esprit was discontinued in 2004.
Darth --
Nil Mortifi, Sine Lucre
You have a limited view of how motorcycles are used. Not everyone who has a motorcycle rides their shiny new Harley on weekends in the summer. Small displacement motorcycles (including scooters and auto-rickshaws) are used in hundreds of countries for daily transportation. Don't confuse "comfortable" with "practical".
In the land of the blind, the one-eyed man is usually crucified.
No, actually this will mean a much more even load on the grid, countering daily peak/off-peak demands, as the vast majority will be plugged in after work, after the end of the daily peak energy spike.
It will also raise the power draw in the winter, which is much lower than summer (thanks to air conditioners).
These two issues together, will make it much more profitable for current power plants (which can be nearer to maximum capacity for longer periods of time) and faster return on investment, because it's more economical to build/run more new power plants.
And before anyone starts ranting about more coal... California has all but outlawed new coal power plants. Natural gas is much more likely, as well as increased solar and wind production... California is the PERFECT area for large-scale utilization of both, hence Sterling Systems/Edison's plans to build or the largest solar power plant in the world in California.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Depends on what you mean by "turbine". There's a big difference between a K27 and a PT6... one is a "turbo charger", the other a full-on turbine engine.
$0.02 (CDN)
automakers are only interested in their own profits.
That's called "fulfilling their fiduciary responsibility to their shareholders." It's a good thing.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Every /. nerd should downlo^H^H^H^H^H^H rent "Who Killed the Electric Car" (trailer.) This documents what happened when GM actually made decent EV.
-- I have a private email server in my basement.
I've been riding motorcycles for 12 years and I've never owned or personally seen a motorcycle that got worse than 35mpg. Most bikes for the US market get somewhere in the range of 40-45mpg. So, either you're doing a horrible job of reading motorcycle specs or you're some sort of incompetent big-oil astroturfer. Your assertion might be true if you limit your search to highly modified huge touring cruisers or racebikes driven by ham-fisted idiots, but even then...
(numbers are from the manufacturer's website, motorcycle.com, or my own personal experience).
All Harley Davidson Sportster 883's are rated 50-55mpg. There are a lot of models in there.
Sportster 1200's models are rated 40-50mpg depending on the exact model.
Evolution engine models are rated right around 40mpg, a smooth hand on the throttle will keep you around 43mpg (personal experience).
Most of the Buell line up (highly modified Sportster 1200 engine) is rated around 45mpg.
600cc Hondas will get better than 40mpg, up to 45mpg depending on how you ride (personal experience). This includes 600f4i, 600rr, and 599.
The Honda Goldwing 1500 is rated at 42mpg. The one I personally know of routinely gets 45mpg. This is a huge luxury tourer.
My wife's Honda Rebel 250 gets 60-65mpg depending on which roads she takes on her commute.
The Suzuki DL-650 is rated at 55mpg and will get almost 60mpg (personal experience).
Suzuki DL-1000 is rated at 45mpg.
Suzuki Hayabusa 1300 is rated at 35mpg and is able to do 200+ mph off the showroom floor. This is the most ridiculously overpowered sportbike on the market.
You should also visit India or anywhere in southeast Asia, where the motorcycles are 80-150cc and the scooters are 50cc. Most of those motorcycles handily exceed 100mpg. The scooters approach 200mpg. In order to achieve these mileage numbers, keeping an average speed at or below 45km/h and shutting off the engine at stoplights becomes important.
The only motorcycle I've heard of that might do as badly as 25mpg is the Boss Hoss. But then they strapped a small-block chevy V8 into a motorcycle as some symbol of excess, so what do you expect.
Ummmm, yeah. That's why all of the new high-efficiency vehicles are using huge displacement V8's. Don't know what you're smoking, but (1) motorcycles get substantially better mileage than anything but non-diesel cars and (2) it's fundamentally due to the smaller quantity of air/fuel mixture burned per mile. Which directly equates to geared displacement. Small engines can be just as efficient per cc as large engines, and ultimately, having the smallest displacement ticking over per mile results in the highest efficiency.
The only actual efficency argument for cars and against motorcycles is that the aerodynamics of a well designed car can trounce the aerodynamics of the best designed motorcycles. So at high speeds, cars begin to catch up to bikes on the efficiency curve. However, for 99.9% of day-to-day driving, the speeds are low enough that the motorcycle mass advantage is much more important than the car's aerodynamic advantage (somewhere around 100-120mph a 600cc sportbike may have the same mileage as a sports car at the same speed). As a result of this reality, I spend about $4 a week on gasoline while being able to pull away from 95% of the cars on the road. My wife spends about $2.50 a week on gasoline and can pull away from 75% of the cars on the road.
Please choose to inform yourself before continuing this conversation.
Ross
someone made one once
Gearing is the thing.
The first naval turbines had the same issues. Running the propellers at turbine speed
cavitated the blades, running the turbine slow meant poor efficiency. There was an
attempt at a fluid coupling ( Foettinger or something like that in Germany ). Between
WWI and WWII, at least the Americans experimented with Turbine electric drives for
ships. ( Lexington or Saratoga ( CV2 && 3 ) powered part of a city in the 1930's because it had
the generating capacity. ). When double reduction gearing became reliable, the wieght
of the electric generating and using gear became a penalty.
So, gearing can change this, or the turbine can run at rated speed, and produce electricity
directly, without any direct "contact" with the drive train. And probably at higher efficiencies
than a conventional piston engine. As noted elsewhere in this thread, the servicability
of the units might be an issue, but I think it one that can be overcome.
emt 377 emt 4
Umm, no. Locomotives don't do any stop & go driving, don't have a large battery pack, can't go an inch without the diesel engine running, etc.
While lacking a battery pack, a locomotive is still 'hybrid' in that it has both a diesel engine and electric motors. There are car type hybrids out there right now that can't go an inch without the engine running, with the battery system only providing a power boost, allowing a smaller engine to be used for the performance. Even then, I read an article about 4 months ago that pointed out that they're starting to build true hybrid locomotives.
The nature of a hybrid the size of a locomotive actually allows more efficiency than a transmission of sufficient strength to move the train. See my point about larger electric motors being more efficient. A locomotive of course has some really big ones. That and you can operate and tune the diesel engine for maximum efficiency because you don't have to worry about the RPM range of a convential gearbox mechanical connect system.
As for hooking multiple locomotives together, there's really no reason that you couldn't do that with direct-drive, it's just a bit easier because of the decoupling of speed/engine RPM and force.
I don't read AC A human right
Uhmmm... yeah. You're a moron.
The reason that turbines are used in airlines has NOTHING to do with maintenance... it's all about power produced, power to weight ratios, and fuel efficiency. Go take a look at the maintenance protocols for a turbine vs. piston powerplants and then get back to me.
And explain to me again why it is that most private / pleasure aircraft are powered by piston engines? Oh yeah... they're much more complex and actually DO require more maintenance. And are much more expensive.
Don't get me wrong, turbines are WAY better from a technical perspective, but realistically are not appropriate for automobiles due to their cost, complexity, fuel requirements (they DON'T run on pump gas), noise, heat generation, etc.
And exactly WHERE are you getting this whole "trouble-free" stuff from? I'm getting it from a guy who's worked on both engines for more than 30 years as a bush pilot and an AME working on everything from Beavers to Twin Otters to Turbo Beavers to Caravans to Bell Jet Rangers and LongHorns.
I think you're just pulling shit out of your ass.
$0.02 (CDN)
You might want to make sure you actually understand what he's saying before you go calling him an idiot. As it is, you're looking a wee bit silly yourself.
His point was that it makes more sense to make SUV's hybrid because it'll make a bigger difference than if you make compact cars hybrid, and he's absolutely correct. The fact that the compact car will still be more fuel-efficient is irrelevant. The fact that my bicycle is still more efficient than your compact car is also irrelevant. What matters is that by making the SUV hybrid you're saving 15+ mpg for those who were going to buy an SUV anyway, whereas by making a car hybrid, you're saving a lot less on a per-vehicle basis.
I call caca del toro on this. The EV1 wasn't even for sale -- GM would only lease it to customers! And when GM finally pulled the plug on the EV1, many of the lessees offered to buy their EV1s but GM flat out refused to sell, choosing instead to repossess every last EV1 and have them crushed (save for a couple that went to museums after being functionally gutted).
Please school yourself before parroting any further GM lies.
Every normal man must be tempted at times to spit on his hands, hoist the black flag, and begin to slit throats.
You're full of crap. the 0-60 time on the 2006 Accord Hybrid is ~6.7 seconds.
.technomancer
I'm not sure what you mean by "You can't put an effective muffler on a turbine engine." The turbine Chryslers back in the 60s had a waste-heat collection system on them that effectively muffled the turbine. In fact, the complaint from the testers was actually that they sounded like a vacuum cleaner.
I am not claiming that turbines would be good in a family car, just that you can muffle the sound.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
WRONG - Turbine engine maintenance is much more predictable, which reduces unplanned costs. Although actual costs are greater, the predictability allows the aircraft to generate more revenue.
Sort of right, sort of wrong. Piston engines are generally more efficient for a given thrust, but can't operate at higher altitudes, and require large propeller disks for high thrust. Jet engines can operate at altitudes high enough where the reduction in drag allows them to be more efficient on a per mile basis. For example, the air density at 40,000 feet is about a fifth of the density near the surface, so drag is significantly less, and this allows the jet to use less fuel. If a piston and a jet aircraft with identical configurations were flown at the same altitude, (assuming it was an altitude within the piston aircraft'sservice ceiling,) the piston aircraft would use less fuel. The jet engine would be lighter, though, than the piston engine and propeller combination.
For a good comparison, look at the BD-5B (piston), BD-5T (turboprop), and BD-5J (turbojet). Very similar aircraft, with the BD-5J having the least range with identical fuel.
And yes, piston engine maintenance costs will be cheaper than the jet engine, on a per engine basis alone. Commercial operators have to consider more than repair and overhaul costs, however. Airlines just pull and replace the engine prior to a major maintenace requirement so that the aircraft can still generate revenue, which allows the predictability of turbine engine maintenance to more than offset the cost savings of piston engine maintenance.
Hope this helps.
You're talking about 2 different operational modes... car travel vs. airline travel.
A jet's turbine will typically run at a constant RPM for long periods of time, whereas a car will be variable RPM and be used for (generally) more frequent, shorter duration trips. If you compare the maintenance required/performed on long-haul (transatlantic?) flights versus short-hop commuter planes (Dash 8's, etc), the transatlantic flights usually require less maintenance. Maintenance is not just about engine time, it's about past performance dynamics.
Such usage behaviour has a LOT to do with the wear and tear on the engine, and the required maintenance as a result. The absolute BEST thing you can do for a turbine engine is to start it up and never shut it down... it will last almost forever. As soon as you start cycling it, thermal expansion/contraction over time plays hell with the tolerances and causes problems.
You're also talking about 2 totally different atmospheric conditions... "ground level" vs. 30,000+ feet. That also has drastic implications with respect to longevity and capabilities. Running a piston engine at altitude will have issues with it running rich, etc. That's one of the advantages of a turbine; it compresses the air before ignition, so that the air:fuel ratios are better maintained, allowing you to get higher efficiency at altitude... in short, more thrust/distance per lbs of fuel.
If you were to put a turbine engine into the operational conditions required by a car, I still think that the turbine would require more maintenance.
Mind you, I'm also talking about existing turbine engine technology, and not taking into account any potential turbine development that could come about. For instance, taking a look at the variable vane turbo technology that Porsche has just developed that they've implemented on their new 997 turbo, the way may very well be paved to allow turbines to sustain the speed and operational temperatures required by "pump gas", etc. They were successful in taking something that typically would only work in the (relatively) low speed, low temp environment of a turbo-diesel environment and implementing it in the gasoline internal combustion environment. (It has a lot to do with the material of the turbine vanes, their size/rotational speeds, and the exhaust heat generated, etc).
My main point, though, is that as things stand right now, a piston engine is much more forgiving of poor or no maintenance, and while it may have more moving parts than a turbine, I think it's generally easier and cheaper to maintain by and for the masses.
$0.02 (CDN)
you may want to look at this site:
http://www.allpar.com/mopar/turbine.html
They worked with turbines before, conspiresests can fill in the rest.
Actually the best benefits (allthough it is tranny related) is the high precision control, IE every wheel on the train is powered, and any-slip on any wheel can be conter-acted in mSec timing. that would be a royal pain with mechanical linkages. same reason it works to link locos, they can share control with electric easier for the same reasons.
Their is the whole thing of running the engine at it's most efficient speed continuously. the whole electric motors and 0 speed torque is crap. The electro motors we use for propulision have a 50:1 gearing reduction and less climbing abilty than the 30:1 reduction in gear 1 of the equivilent mechanical Diesiel tranny. also electro motors are incredibly in-efficient at stall, and will overheat/burnout quickly if used their for long (but they do have good torque their, without the required slippage of a mechanical link.) The huge torque pay-off is the ability to run a huge gear reduction, and the very wide torque range of electric allows you to do that at a fixed reduction.
Point taken.
I shouldn't have said the decision has "nothing" to do with maintenance, as it's a part of the big picture.
But forgetting maintenance, it's much more efficient and cost effective to run turbines at altitude. Throwing maintenance factors into the equations and it's still a better ROI to run turbines than pistons.
Especially when you're talking about ETA for the customer.
For short hops (commuters, etc) turbo-props are more cost effective, for long-haul (cross country, intercontinental, etc), turbojet is the way to go.
A number of executive "jets" are now going to turbo prop (Piaggio P180 for instance) due to their cost effectiveness. Not as fast getting you there, but way cheaper. Not having to deal with domestic air carriers is enough of a reward to justify the slightly longer ETA.
$0.02 (CDN)
"Large piston-engine planes like the B36 bomber had passages so that the crew could access the engines in flight. Why? because they needed vastly more maintenance than jet engines, so much so that were expected to routinely break down in flight."
The B-36 was pretty much the only one in the late 1940s. A few had this before. The issue was more the reliability of engines in that time period in combat than anything else. Most large piston engined bombers of the 1940s did NOT have crew accessible engines.