GM's 6.2L V-8 delivers 450 HP and 450 lb-ft of torque to the 2014 Chevrolet Corvette. It employs a direct injection fuel system, active fuel management, and variable valve timing. GM engineers used computational fluid dynamics to optimize the combustion system and ensure a more complete burn. (Source: Chevrolet)
Thanks for this, Chuck! We seem to be continuing our more than century-old love affair with automobiles. Maybe that is having a strong effect on our new designs.
I'm not a powertrain engineer, but perhaps yourself or others can help me out. It's my layman understanding that modern Diesel locomotives are Diesel-Electric hybrids, having a very efficient Diesel-fueled turbine that does one thing well... it turns an electric generator. Because the turbine does one thing well, it can be optimized for power, torque, fuel-consumption, etc. to produce electricity. The electricity is then used to power the traction motors that have no mechanical transmission or clutch -- all through the magic of magnetic field induction. The electric motors do one thing well, they turn the drive shaft. As far as power goes, Wikipedia lists that a modern Diesel locomotive can start moving trains weighing in excess of 15,000 tons. The M1 Abrams tank uses a 1,500-hp gas turbine engine, but uses a mechanical hydrokinetic transmission.
I continue to be perplexed as to why the Automobile industry does not integrate technology that has been successfully developed by other industries. I would have thought that General Electric would have used their turbine expertise to capture the automobile market by now. And I don't know about you, but as far as keeping the motorheads happy, if folks get excited about a "turbocharged" engine, I would love to be on the marketing team for the first "turbine jet" powered commercial automobile...
williamweaver, Diesel Electric Locomotives are similar to hybrid cars except for one thing, the battery. This is changing, of course. Even though they are very efficient, making them more efficient is worthwhile, considering how much they are used. Actually, GE is taking the next step and putitng in batteries. These can be charged during operations and can recover energy while braking. They then provide low speed power which is more responsive than the diesel gen set.
As for turbines in cars, it has been tried. A maker of microturbines, Capstone, ran a test of a 10kw microturbine genset in a small car a couple of years back. Looking at their web site now, they do have gensets, 30kw and 65kw, for larger vehicles, like busses. These cost more to buy, but are much cheaper to maintain and get much better mileage than standard diesel engines. I don't have any information on why the smaller turbine project was not pursued. If these types of systems were used for trucks and busses, though, it would lower our use of fuel overall. In addition, they can run on multiple fuels, liquid and gas. My experience was with gas, but they can also use diesel and kerosene. Perhaps in the future they will be sized for automobiles.
I believe Chrysler had a turbine car in the early Sixties. It had a number of new technology problems, but I think the biggest issue was that a turbine engine needs to spool up, so acceleration was rather poor. If only they made merge lanes as long as runways.
The most famous turbine engine, of course, was the one in Parnelli Jones' car at Indy in 1967. The car left the race with three laps to go when a transmission bearing broke. I believe turbine engines were barred from Indy races afterward.
Thanks for that tekochip. That's why I'm wondering why we don't use turbine technology to charge / recharge the batteries of a modern hybrid. Not being an engineer, I find statements like "the relatively constant torque of an electric motor, even at very low speeds tends to increase acceleration performance of an electric vehicle relative to that of the same rated motor power internal combustion engine" (Wikipedia) promising. Instead of developing new transmission technology to mechanically couple the output of the turbine to the differential, it seems an obvious mashup to use an efficient turbine to generate electricity for a modern electric car.
And Chuck, all the more efficient if we use diesel. I've read of several "gas" turbines that accept methane, gasoline, kerosene, diesel, and Jet A. Now I just need to develop one...
"The Jaguar C-X75, the concept that debuted at the 2010 Paris Motor Show, is an electric hybrid that uses two small gas-powered turbines to generate electricity when the battery is low. Looking at the stats, it's an impressive ride: an estimated fuel economy of 41.1 mpg, 778 horsepower, 0 to 62mph in 3.4 seconds, and a top speed of 205 mph."
Personally, Bill, I'd be happy just to see the U.S. car industry make more use of diesel technology. Diesel fuel has about 10% more energy per volume than conventional gasoline. The problem, though, is that diesel engine technology is more expensive. One industry engineer told me that the base diesel engine is about 2X as expensive to make as a regular gasoline engine.
Being a huge railfan, I have to tell you that modern diesel electric locomotives do not have turbines. They feature traditional piston driven diesel engines connected to an alternator. I believe the the General Electric locomotives feature four stroke diesel engines, while the Electro-Motive Diesels (a.k.a EMD) (formerly owned by General Motors) feature two stroke diesel engines. Both manufactures utilize turbo charging.
I sure like the sound of the EMDs better than that of the GE's.
It was interesting that there was a horsepower race by the locomotive builders about ten years ago, and it ended with both companies making 6000 horsepower locomotives. Ironically, they both seemed to have problems and lost favor with the railroads. They both now produce their largest units with about 4500 horsepower, which seems to be the sweet spot. Since additional locomotives can be attached together to be operated by lead locomotive (MU'd meaning Multiple Units), more locomotives can be added when they need extra power.
Thanks for that Jim_E! Wow... I love learning new stuff. I had no idea that GE made traditional reciprocating engines. Shows how biased I am from working with the Air Force... the only piston engines from GE I saw were housed in the Air Force Museum.
Perhaps I confused GE with General Dyamics (GD)... Their M1 Abrams Tank uses a gas turbine engine and I mistakenly thought they had borrowed that technology from Locomotives (it's a heavy, freaking tank after all). A quick visit to ge.com reveals that their modern locomotives use a 12-cylender diesel engine. Thanks for the reality check!
Looks like the Gas Turbine-Electric Locomotives peaked in the 1960s. I guess I'm only missing 50 years of technology... =]
Yeah, the 60's were when the Union Pacific experimented with their "Big Blow" locomotives. There are some interesting stories about the exhaust from one melting a road on an overpass above the tracks when the locomotive stopped underneath....
There was also the "turbotrain" which was a turbine powered (mechanical drive I believe) passenger train. A few still exist, but are for sale:
Europe used and uses diesel hydraulics, but when tried here in the 1970's, they didn't work too well.
In the 1980's, GE built a "coal slurry" powered diesel electric locomotive, but apparently there was too much wear on engine internals from the fuel.
GE is supposedly working on a diesel electric locomotive with on-board battery storage, but we all know about the limitations of batteries.
One of the big things these days, is for smaller switching locomotives to be "genset" equipped. Basically, instead of having one large diesel engine, they have three smaller diesel engines, which can come on-line as more power is needed.
Norfolk Southern has an experimental, completely battery powered locomotive (number 999), but it has a very limited range, and uses traditional lead acid batteries.
The Pennsylvania railroad had electrified some of their Eastern railroad and used to operate electric freight locomotives, but after Conrail came around to rescue the North-East's railroads, they phased out much of the electrical territories and stopped all electric powered freight trains.
A nuclear powered locomotive would be pretty cool....
Those who do not study history... Back in the early 1930's the German railways compared four different power transmission methods in four locomotives powered by identical diesel engines. The diesel mechanical was poor. The diesel hydraulic didn't turn them on. Diesel electric worked well. The best, clearly, was a diesel-pneumatic locomotive, more fuel-efficient and faster. What worked well then would work well now, especially as a hybrid, storing energy in compressed air tanks (simple ferrous metal or composite technology) instead of expensive batteries. (see US patent 5,832,728) The diesel engine drives an air pump, which could be interal with the engine, and the air supplies a "steam engine" (the drive motor). (the Germans converted a steam locomotive) There are two tricks which make it practical:
(1) Cool the pump by injecting water, so the output is a mixture of air and steam. As the air expands, doing work, the steam condenses, and the latent heat reheats the air. It thermodynamically efficient: cool air and water in, cool air and water out, little wasted heat. (Filter out the water droplets and you can drink them or recycle them)
(2) Use waste heat from the diesel exhaust to heat the pump output, getting "something for nothing."
In the modern context, add some storage tanks. (At 30 bar, 300C, you can store about a kilowatt-hour per cubic foot) For regenerative braking, use "engine braking" where the pump is driven by the vehicle momentum and puts the output into a tank instead of the drive motor.
There are no scarce or toxic materials involved, and the technology is simple and mature. Hitler wanted the fuel for tanks and planes, so the German railroads scrapped their diesels, but what they could do in 1932 should be easy 80 years later and applicable to automobiles. If I had the money, I'd convert a diesel truck, putting enough scuba tanks in or under the bed to have a pollution-free range of 100 miles on stored air. With the tanks full, I could drag race Corvettes.
Looking at some of the MPG ratings that are stated in the slideshow, and checking some online, where is the fuel economy? I have a 1990 GMC Suburban 5.7L that I can get upto 20 MPG by just using good driving habits to maximize mileage. I have a 1968 Tempest with a 5.7L that I have been able to get 21 MPG with good driving habits. I realize that these would get even better mileage by using the same driving habits. But the cost of this research and development is improving thesevehicle MPG by about 5 - 7 MPG. That is 20%, not bad, but still a long way off from 51.4 MPG!
I got to thinking, what is the energy content in one gallon of gasoline and how much work can it generate to move a 4000 pound vehicle? The process of electrification is only covering up the conversion problem. As William pointed out, how about optimizing the conversion by using turbine poweres generators. Seems this is a idea that needs some more thought.
GTOlover, this is one of my favorite Wikipedia Pages http://en.wikipedia.org/wiki/Energy_density. I agree with you in separating the variables. One is the variable of how much Total Energy can you carry on board in the form of fuel while you are traveling and a second variable is how efficiently can the energy in the fuel be Converted into kinetic energy of the vehicle. I think the automobile industry is currently suffering from the "Opportunity Costs of Legacies". We've been doing the same thing for such a long time that it is proven technology, accepted by the regulators, entrenched in our supply chains, and there is a huge activation cost for thinking outside the 20th-century box. We don't keep an account of Opportunity Cost, but I would anticipate that the cost savings we are missing out on by drowning in our current technological inertia would far outstrip the actual costs of not innovating...
The auto companies are still stuck in their old way of thinking. The primary sales tactic that they have used to sell their cars is by defining "improved" as having more HP and faster acceleration. Granted the Corvette is a specialty car, being sold based on performance. However maybe chopping some of the fat off of it's 3200 lb frame with some advanced materials might not require 440 hp to move a bit quicker...
Only about 12% of the energy burned by a "modern" car translates into motion, that why they have such gigantic cooling systems. Hopefully the companies will use their time and money wisely and not just try to "run out the clock" before the 54mpg standard kickes in.
One point made about driving habits improving mileage is well taken. However human nature is hard to change (I can't get my wife to lighten up her lead foot for example as long as I'm paying for the gas and repairs) but the self drive car could very well change that especially if it includes networked roadways whereby the cars communicate with each other, maybe even "drafting" safely to save fuel.
The biggest advantage to having electric motor(s) in the drivetrain is the ability to capture wasted energy during decelleration & braking that would otherwise be shed as waste heat. I wish the industry would think less about batteries for long-term energy storage in electric hybrid vehicles and develop the use of super-capacators instead for acceleration-assist in hybrids. That way you would get much of the fuel economy gains of battery hybrids without the fuel economy negative of the battery weight.
The new Corvette is too heavy? What other car company offers a sports car with 450 horsepower that only weighs 3,200 pounds (50-50 weight distribution), and for only $59,000? The new 'Vette is rated 16 mpg city/26 mpg highway. The new Corvette has an aluminum frame (not steel uni-body) and carbon-fiber bonded to aluminum for the underbody panels to reduce weight. Most midsize cars weight from 3,500 to 4,000 or more pounds.
The Ferrari F430 weighs just 3,195 pounds with 483 horsepower, will set you back about $248,903, but only gets 12 miles per gallon. The Ferrari Enzo weighs 3,230 pounds, 650 Hp, 13 mpg, just $652,830 cost. Ford GT weighs 3,390 pounds, 500 Hp, 15 mpg, $150,525. Lamborghini Gallardo Superleggera weighs 3,320 pounds, 522 Hp, 11 mpg, only $255,745. The little entry-model BMW 135i couple weighs 3,340 pounds, 300 Hp, 20 mpg, $43,670 (all other BMW's weigh more). For comparison sake, the Toyota Prius hybrid weighs about 3,050 pounds. My 2012 Honda Civic EX-L weighs about 2,800 pounds, and a sports car it is not.
The 1956 corvette weighed 3020 lbs, seems that the new model is a step backward. It only cost $3120 also, another step backward. It was a much prettier car also, the new one looks like a recycled Dodge Viper. So for an extra $56,000 what do you get? it doesn't look a lot better to me. The '56 will sell for a lot more also, and get you more girls...
My point is that the auto industry has inched forward for 55 years and all they give you an extra 200 lbs of car with an extra 170 hp, and not much better mileage. How do they get away with it?
If consumers don't buy it, manufacturers won't make it. The Corvette is one of the best selling and best performing 2-seater sports cars in the world. That's how they get away with it.
The 1956 Corvette may have weighed less than the new Corvette, but it can't compete in any area of performance, including fuel economy and smog (I can smell the hydrocarbons from all older cars)...acceleration, braking, handling and safety are absolutely no contest. I'm not sure what the adjusted 1956 price of $3,120 would be today, but that was a lot of money back then. Try to buy a new-condition 1956 Corvette today for only a few thousand dollars. As for any car styling, pure subjective, some prefer older, many prefer newer.
My point is that the new Corvette competes very well in it's market. It is lightweight and low cost for what it is, and a specialty vehicle as you stated. Look at other car classes if you want an ultra-lightweight economy car. The new Fiat 500 weighs just 2,363 with manual transmission. The super-small 70 Hp Smart car weighs just 1,808 pounds, you can get one for around $12,000.
My weekend recreational old-car is a factory stock 1998 Chevrolet Camaro Z28 with 305 Hp (340 ft-lbs torque) 5.7 litre aluminum LT V8 with six-speed manual transmission, about 3,450 pounds. It gets 15 mpg city with my aggressive driving, 26 mpg freeway (California) doing 80 miles per hour. It does zero to 60 mph in 5 seconds flat, the factory top speed is 165 miles per hour.
No disrespect is intended, I'm just making my point.
No doubt the auto manufactures are clinging onto the ICE technology like a monkey clings onto a cookie in a cookie jar (delaying the inevitable notion that letting go is a better idea). The future is coming, and our automotive companies are still thinking in the past, though I am impressed that dispite all the complaining that the mileage goal could never be met (I was never fooled), there is a lot of ideas that still can be used with ICEs to increase mileage.
Complxexity. A diesel engine is a beautiful thing, but they have to add injectors and and an injector pump or Electronic injectors. All require extreme precision, and add another level of complexity. As the injectors inject fuel into the cylinders they have to be able to deal with all the forces of combustion. Gasoline fuel injection is (with the exception of some experimental direct injection systems) done into the low pressure manifold so the only pressure they see is the 30 to 60 PSI delivery pressure of the fuel.
Service on a diesel can be a shocker. almost the same price for the injector pump and injectors as for the rest of the engine.
Al, I have to admit that I'm not sure if the 2X figure is right. That figure was based on the comment of one automotive engineer (who, by the way, does have a Ph.D. with a specialty in engine design). That said, the cost for diesel engines is much higher than for gasoline engines. One big reason is higher operating pressures. All parts are more costly -- blocks, heads, pistons, crankshafts, connecting rods and more, I'm told.
Charles, all the parts are not even 20% more costly, other than the significantly lower production volume problem which transfer higher NRE costs to each unit, for design, prototyping, tooling, testings, certification, ... etc. Certainly the materials are not 2X in cost, or they would be 2x beefier. It's really hard to see that looking at a VW 1.9L TDI diesel from 10 years ago. Other than slightly larger bearings, it's pretty much scaled to a 1.9L gas engine. With significantly higher fuel economy.
Or for that matter a GM 6.5L diesel from 10 years ago, compared to the 350 and 454 derivative designs that it competes with, where it's towing performance is between the two, and significantly better fuel economy than either.
One other thing that has held back diesel in this country, as opposed to European countries, is the difference in the way fuel is taxed. As I understand it, European countries has "subsidized" diesel fuel (in other words, it isn't taxed as heavily as gasoline), or so I'm told.
I live in Europe and have a diesel-engine vehicle, and I don't know for sure if this is true but it makes sense, as it's less expensive than gasoline here. Overall, most people here prefer to have a diesel engine over a gasoline-powered one.
Charles, I'm not sure it's taxes ... they tend to be not a significant factor, even with a bias to try and balance road repair based on typical vehicle axle weights between the two fuels. I think it's more the strong environmentalist dislike for "dirty diesel" because of visible exhaust particulates on smell differences.
Cost of fuel is a small factor, in that we have gone thru several reductions of sulfur, that have caused higher diesel prices as forumations changed. But in general, fuel economy differences, mitigate most of that higher per gallon sticker shock.
My ex-wife got upset when the sulfur content was dropped 15 years ago, and diesel prices spiked for a while. She asked that her 1982 2WD 6.2L suburban (averaging 20mpg) be replaced with a gas 1994 350 model (averaging 15mpg) ... and was suprised when her weekly fuel costs jumped 20% because of relatively poor fuel economy.
Take for example this 1985 S15 2WD diesel truck (http://www.fueleconomy.gov/feg/noframes/1488.shtml) at 27mpg combined, with it's gas equiv at 19mpg combined (http://www.fueleconomy.gov/feg/noframes/1492.shtml)
Being rural, we stack up quite a few more miles per year, in the 30-50K/yr range, so diesels tend to save about $3k/yr in fuel costs. We also tend to run our trucks to 500K miles over their lifetime (one of two new engines), so that savings in fuel cost exceeds the purchase price of the truck.
So far we have taken a 1963 corvair, a 1982 6.2L Suburban, a 1985 C3500 6.2L dually, a 1985 1/2ton stepside pickup over 500K miles ... and a couple others well over 300K miles. The 2001 TDI Beetle is now over 300K with a new enginee. My 1997 K2500 6.5L Suburban is my shop at 300K now, for a new engine and trans, and is likely to be the next to go over 500K inside the next 10 years.
Diesel is just cheaper to operate ... both in fuel cost, and repairs. That adds up significantly, to cover the entire purchase cost of a car/truck if operated over 300K miles.
I never thought car powertrain technology could be so interesting, being someone who is not savvy about cars in the slightest, but your slideshow was enlightening, Charles. It's nice to see what's being done to create more fuel efficiency. It is sorely needed!
That would be quite a feat! As with so many other technologies, I am surprised it too so long for this to evolve, as even when I was young oh so many years ago, people were talking about electric cars...but they didn't really start manufacturing them until 20 years later. Lack of interest and investment then, of course. Now it's practically necessary to go in this direction.
Charles, my concern over 54.5 fleet MPG remains ... and your selection of examples is pretty clear. the only car close to that, is the sub compact at 40mpg. We still seem headed to the previous CAFE results where huge numbers of cars will be produced that lack critical crumple zones to ride down crashes with stationary objects that kill and severely injure the driver and passengers. This will raise cost of insurance in the long run, increasing cost of ownership.
All of these engines have significantly higher complexity, which frequently translates to significantly higher initial purchase costs, as well as increased lifetime maintenence costs, raising cost of ownership significantly.
Minimum wage is unlikely to increase as fast, so the poor people will see a higher portion of their income moved to transportation, both cost of ownership and fuel cost, while accident rates increase.
Overall, this will drive inflation in our economy to meet a politically motivated goal of removing automobiles from our society.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.