MB Chris posits the following:
A straight EV at this point isn’t very useful to many people because of the current technology’s limitations. And, for me, hybrids are far too expensive and complicated to consider buying. I’m an ASE certified mechanic (25 years) and work in automotive manufacturing (nobody very important). The big thing that I can’t figure out about hybrids is why have a conventional drivetrain at all? Why not have the car operate similar to a diesel electric locomotive? Drive a large alternator with a combustion engine designed to run most efficiently at [a certain] RPM. Have no idle at all. It’s either on driving the alternator or not running. NVH engineering would only be needed to cope with that one RPM and startup/stop. Put an electric motor to drive each rear wheel. Mount them inboard so unsprung weight will not be increased. Even 4 electric motors or one on each axle if you want AWD. No transmission, driveshaft or differential is needed. That would come close to offsetting the weight of the battery pack.
IC engines are controlled by wire so why not just control the output of electric motors? Seems to me that an engine designed to run most efficiently at one RPM would be far more fuel efficient than the current crop of hybrids. Some redundancy is automatically built in. If one electric motor quits you can still move with the remaining motor to a place of repair. If your IC engine quits you can still move a small distance to a repair center or safe place (depending on the battery state of charge). Same with the alternator failure. Making a system like this and able to be a plug in would be even better. This type system would work for daily commute as well as long trips. Finally, this system should be less expensive without the transmission and differential. Those parts would offset part of the cost of the battery pack. What do you think?
Seems right to me. Now lets just wait for people with honest to god engineering degrees to tell us why this is not currently feasible. (But I think the development would be worth it, how long have GM and GE been building locomotives like this?)
I’m not an expert in this field, but I’d would guess run time is an issue. Railroad power units run for hours or days at time non-stop a fairly constant speed and flat inclines. Cars run short start-and-start trips at a wide range of speeds, road contours and distances. This may be the reason railroad electric technology is difficult to use in automotive applications.
Size economie of scale a probably another issue. A hundred ton power unit pulling millions of tons of coal cars is different than a 4,000 car.
Twotone
All of the locomotives I have driven include 8 throttle positions (N#) and the RPM does vary a large amount between N1 and N8. Also they are most often left idling for long periods of time when not in use. Only the newest generation locos will shut the diesel engine down after 15 minutes of inactivity (only in the summer), it takes more than 3 minutes to restart if you want to move again. The only advantage is that as you say there is no drivetrain to wear out.
Trust me you don’t want a car similar to a train.
The big thing that I can’t figure out about hybrids is why have a conventional drivetrain at all?
Because, transmitting the the engine’s power to the wheels via a mechanical transmission is more energy efficient than first converting the energy into electricity and then converting that electricy back into work via an electric motor.
For example – the Leibherr T 282B converts its 3650bhp to electricity to drive motors in the rear axle. The Caterpillar 797B uses a 7-speed automatic transmission to transmit its 4000bhp. Caterpillar claims this results in increased fuel efficiency.
Toyota uses the hybrid drive to take advantage of the efficiency of a tradational transmission while also having the ablity to use regenerative braking and using the batttery and electric motor to suppliment the small ICE.
Then you ma ask why are locamotives diesel-electric?
As far as I know it has to do with their need to use dynamic braking.
http://en.wikipedia.org/wiki/Dynamic_braking
They have… Its called the Chevy Volt in gas-burning mode.
-@Twotone
Runtime can not be an issue. Are you aware many cab companies rent out their cabs to a multitude of drivers on a 24hr/7 basis ? We are talking here about three year old Taurus and Impala vehicles that just came off lease. My belief is that it is the thermal cycling of less frequently used vehicles perhaps used only twice per day which is more likely to encourage failure due to temperature expansion and contraction of the oil seals and electrical connectors.
the reason trains use that type of drive train is, that a transmission would be too complicated. the generator-Emotor basically is the transmission. Obviously there is some losses from geenrator and E-motor that probably are larger than in a transmission. Maybe nowadays the E-equipment is more efficient, though
However, I kind of think that would be nice concept in cars when using a battery a buffer or for short distances.
the IC engine should run at different speeds. Over long driving you need very little power in the city, but very much at high speed. If the engine ran at the same speed all the time, it always would shut off in city traffic and turn on and so on.
I can’t see how a car engine feeding a generator, feeding an inverter, feeding 4 motors is any lighter or more efficient, yet, than a conventional setup. Maybe in another generation or two. Then again, with pinpoint control of every wheel, you could come up with a car that puts any mechanical AWD system out there to shame…
As for locomotives? What few diesels still sold in Europe are generally low powered switchers, thus often diesel hydraulic. Ever since multisystem electrics have become poplar, diesels have been in steep decline, except for switchers, though SBB recently picked up a fleet of electric switchers/light duty units.
The US is the only major industrialized country that still has no extensive RR electrification network…
why not drive the wheels hydraulically? small diesel that only increases rpm’s when load is applied. Wheel motors similar to a zero turn lawn mower stepped up at the hub ( direct the fluid at varied fins in side the hub like a ten speed bike ) for increased rpm or a decreasing nozzle size driving the rotors inside the hub?
Are we outside the box yet?
Shit, you got me – I’m no engineer.
But didn’t I read that the GM hydrogen car (hy-wire?) had a similar system – one hydrogen fuel cell powering wheel-mounted electric motors?
-@jmo
Because, transmitting the the engine’s power to the wheels via a mechanical transmission is more energy efficient than first converting the energy into electricity and then converting that electricy back into work via an electric motor.
If this statement were on Wikipedia I’d be slapping a big fat “citation needed” sign on it !!
why not drive the wheels hydraulically?
As far as I know UPS is rolling out a fleet of HHV (Hybrid Hydraulic Vehicles) as we speak.
T2,
If this statement were on Wikipedia I’d be slapping a big fat “citation needed” sign on it !!
I’m only saying that’s why CAT claims its 797B is bettr than the Leibherr T282B.
http://www.cat.com/cda/layout?m=308657&x=7
I’ve thought the same. Have a small diesel run to charge batteries and have an electric drive full time. The diesel runs only to charge the batteries. I think Toyota is using the technology gained from the Prius in their other conventional cars, and so taking the engineering expense and spreading it over many platforms. My Scion has electric power steering, not electric/hydraulic, but pure electric powered by a small electric motor at the end of the steering shaft. It’s light and seems to work well. Feel is another matter. My accelerator pedal is electric. No linkage to the throttle body. I think the systems can be light weight and, with the experience culled from the Prius, fairly reliable. The real world experience gathered by Toyota with the Prius is putting them years ahead of the still vaporware Volt.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V78-3VVT4XD-K&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1025245644&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ec3143054e8dc588adac31a8c97f93b3
There you go, but you have to buy the paper.
Diesel locomotives use electric traction motors because only electric motors develop torque even when not spinning. Imagine the weight of a long freight train and the torque needed to get it moving from a stop.
Dynamic braking is not found in all diesels locomotives and requires massive cooling resistor pads to dissipate electricity generated by dynamic braking.
It’s simply a matter of physics, power loss, and weight why a locomotive set up doesn’t work on a car.
I nominate MBChris for the Bob Nardelli award. Our favorite minimum-whipping-boy asked the same question almost 2 years ago. After all, he was at GE and saw those fancy drivetrains in action.
Turns out the magical offset-game of taking out one part to replace with another falls apart during implementation phase. Especially when you’re trying to make money in different business models. Contrary to belief, a ICE is extremely cheap on the supply-side compared to the alternatives. Yes, it slowly kills the Earth, but that doesn’t come into play on the margin equation unless the government fines people.
We aren’t dealing with Legos here – comparing trains to $20,000 vehicles may be fun on paper, but starts falling apart during implementation.
That’s why efforts to slap an electic motor capable of highway speeds into a car usually makes said vehicle cost much more to produce than would be intuitively expected. Some firms have experimented with putting a motor, brake, etc into the wheel assembly itself while others opt for a single big electric motor (Tesla). But the only pragmatic implementation thus far for volume auto sales has been to piggy back off of the standard ICE.
However, for those tinkerers and smart people who have a revolutionary idea….. please actually try to get into the industry somehow and apply your thinking into producing tangible output. Challenging the status quo is only beneficial if tangible action is taken.
I’ve been thinking the same, as well. Perhaps having electric motors compact, powerful, and efficient enough is still an issue. Then you need to waterproof them. Or at least having trucks diesel-electric; for them it should be easier to implement than on cars.
“The US is the only major industrialized country that still has no extensive RR electrification network…”
I wouldn’t consider the Amtrak Northeast Corridor to not be “extensive”. The Washington, D.C. to New Haven, CT portion has been electrified since 1934 and New Haven to Boston portion came about 8 or 9 years ago. Additionally, the massive U.S. subway systems such as NYC, D.C., Boston, Chicago, et al. all electrified; NYC since 1910.
The extensive U.S. rail network, unlike Europe, is a freight system and dieselized because that’s what’s needed to haul a 10,000 ton drag over a 1.5% grade. There have been extensive electric freight networks in the U.S. over time such as the western extension of the “Milwaulkee Road” (Chicago, Milwaulkee, St. Paul and Pacific RR) which was electrified across three of four western states as recently as 1973. The “Virginian” which ran from West Virginia coal mines to the tidewater area of Norfolk, VA was also electrified until its demise in the early 60’s. In both instances, electric systems were not efficient at moving the ever increasing freight tonnage so they were scrapped.
Yes teh clutch on a train would burn to hell if accelerating a 1000 ton train ;-)
another thought about wheel motors, they could not only be superior to any AWD, they also would bring VSC (Vehicle stability control) to new spheres.
VSC currently decelerates certain wheel, now we could accelerate certain wheels to avoid spinning f the car
Locomotives are also diesel electric because it would be impractical to run a mechanical drive shaft to every car its pulling – in that case electricity makes much more sense even though there is some energy loss during the generation phase.
VSC currently decelerates certain wheel, now we could accelerate certain wheels to avoid spinning f the car
That already have that – Acura’s Super Handling All-Wheel-Drive.
http://www.topspeed.com/cars/automotive-glossary/super-handling-all-wheel-drive-system-ar16052.html
@carguy
Freight cars pulled by a diesel locomotive are not powered in any way. However they all have their own air brakes. Air pressure is provided by the locomotive, if there is a break in the train pressure is lost and ALL brakes come on at once.
MB Chris, I think you are right on in your approach. I’ve started a company in Silicon Valley that will make (we hope) a car with four in-wheel motors, a central car controller, by-wire throttle, steering and braking, and a generator that produces only electricity.
Our plans are for a four-door, five-seat sedan that sells for $35,000 and averages 100 miles per gallon. We think we can also go from 0 to 60 miles per hour in 5 seconds.
There is no guarantee that we can do what we hope. But thinking along the same lines you do, we think the technology is there.
Didn’t you pretty much describe a serial hybrid, eg the Chevy Volt?
The real advance for electric drive will have to be eliminating the ICE and generating electricity by other means. The heat loss wastes fuel and complexity of the ICE makes it expensive to build and maintain. A simpler fuel BTU capture/heat transfer is needed for generating electricity.
Inventor Bill Lear (car radios, 8-track tapes, Lear jet) tried in the early 70’s to develop a bus with electric motors at the wheels, using electricity generated by the diesel engine, and ran into a ton of technical problems. He died before they were solved and the effort was abandoned.
If you’re going to try something new, keep it simple, at first. A single electric motor directly driving the rear wheels is as simple as you can get, and there are plenty of existing cars and trucks that can accommodate it.
@holydonut:
Correct me if I’m wrong, but it’s my understanding that modern electric motors have no problem with freeway speeds or high-performance driving, and are perhaps even ideally suited for it. I thought the main problem with a pure EV drivetrain at this point is pretty much the battery, which still needs higher energy density and lower prices.
In San Francisco, we already have buses that are serial hybrids, like locomotives. I think I remember reading that they’re essentially powered by the same ICE that drives a large Dodge pickup.
I’ve ridden on them, and they’re pretty nice. Smooth ride, no lurching, quieter, with a lower floor in the first two-thirds of the cabin that makes it easier getting on and off.
I’m with Michael Blue; at least do this with Class 8 trucks.
But then why have a battery at all? Trains don’t, at least not battery capacity in significant enough quantities to power the train enough to move anywhere. Same with trucks; diesel engine (just a much smaller one), generator, electric motor to the wheels without gear reduction. Eliminating the gear reduction of a mechanical drive train eliminates the added expense of high-speed/high-power electric motors by letting them stay in a lower and more efficient speed.
Trucking is largely done by company trucks and employed drivers and in these applications the driver’s comfort and enjoyment behind the wheel is a non-consideration. Disjointed road/engine speeds or intermittent NVH issues during load changes would fade into obscurity when the fleet buyer sees the reduction in operating cost of what could knock on double-digit fuel efficiency (that would be a 25-40% increase).
Army is playing with a hybrid on this principle, called “Aggressor” or some such. It seems to stuck in trials since 2004.
@healthy skeptic
I have no doubt an electric motor is capable of propelling a vehicle on US Roadways. My point was no volume produced vehicles are available today for people to buy as reasonably priced alternatives to what they are accustomed to for personal transportation. I figured somebody would pick semantics by presenting golf-carts and GEM vehicles as examples of electric drive vehicles that sell in decent volume. But I failed to clarify the difference between making something work and making something profitable.
It is not simply “the battery” because there’s a difference between making something function versus making something profitable. Dozens of items on electric cars cost more than on a ICE equipped car with vacuum hoses and constantly spinning belts. From a consumer standpoint I think they tend to focus on the will-it-work aspect and they tend to oversimplify things. This is because many people hold an often flawed assumption that if there are buyers, then sellers should be able to money by providing those consumers with goods/services. Unfortunately, making money with the available demand has proven to be the biggest challenge regarding non ICE vehicles for the masses.
Thus far, electric-only alternatives have proven to be unsustainable in the marketplace for high volume sales. These vehicles either cost too much money or had insufficient features. The concessions required to chose the electric-only alternative usually meant that consumers would rather stay with the regular vehicles that they can find at the local automall. Similarly, some vehicles didn’t make the supplier/seller money, so those sellers found other things they could make more profit by selling.
The EV1 and other all-electric vehicles, hydrogen vehicles, CNG conversions, etc come and go (again, I’m talking about vehicles for the masses and not fleet/government use). These vehicles represent the evolution of technology and the hope of new ideas. Unfortunately no vehicles (except hybrids that rely on a base ICE) have completely satisfied both conditions where the volume/price of demand results in long-term profit for the producer and the vehicle is something that people want to buy at the equilibrium price points.
Cool! I want traction motors nestled in triple axle bogies at each end of my Chevy Volt.
Trucking is largely done by company trucks and employed drivers and in these applications the driver’s comfort and enjoyment behind the wheel is a non consideration.
Sure glad I don’t work for you.
Design “compromise” is the concept to wrestle with.
There are many approaches that might be ideal, seem energy effective or even cost effective.
In any product design (not pure engineering pursuit) you almost always have to compromise in all directions.
The Toyota Hybrid Synergy Drive system is a beautiful set of compromises. Cost, energy effectiveness, weight. It’s not even complicated, although it continues to stump some.
A (freight) locomotive needs massive torque for a very short period of time. You can get nearly any configuration of torque multiplication you want from a diesel electric config. It is extremely expensive and very heavy to tackle that with a geared transmission which might be more efficient.
Once the train is moving the energy input required to maintain the constant speed is very low, so a less efficient diesel-electric set is a valid compromise. The inefficiency impact occurs at low levels of power output, so the penalty is acceptable.
A large Liebherr dumpster uses diesel electric to save weight in it’s class and multiply torque also (> 300t). We’re not talking Cat 770 (~42t) sized machines in this class. Geared transmissions handle that no problems. Another example is dozers; they’re geared because it’s cheaper and the added weight is (usually) OK.
I think that this idea has merit, but the problem is that using an IC piston engine is not the most efficient IC engine in existence, that falls to the gas turbine.
Volvo tried this concept in the 90s.
I think that this still might be the way to go with an electric car, but none of the major car manufacturers have any experience with gas turbines. Perhaps a GE or P&W joint venture with another company might produce such a vehicle?
I don’t know what this has not been experimented with more.
You want everyone to drive an Abrams?
One reason electric motors are so useful on trains is that they offer highest torque at or near dead stop of their rotational speed, a huge advantage over direct drive steam (their principle competition years ago), gasoline or diesel power plants.
The earliest train motors were brush-fed DC designs, but only because more efficient AC designs either didn’t exist or were too complex and expensive. However, AC motors are not as prone to brush or commuter burnouts at full power during dead stops.
Today, AC-powered locomotives, while common, are still far more expensive than DC-powered units.
http://en.wikipedia.org/wiki/Diesel_locomotive
tells much more.
@rpol35:
I wouldn’t consider the Amtrak Northeast Corridor to not be “extensive”. The Washington, D.C. to New Haven, CT portion has been electrified since 1934 and New Haven to Boston portion came about 8 or 9 years ago.
Vs Germany (10,000+ miles), Italy (10,000+), France (20,000+), and most of Europe, it isn’t much. And by percentage of route, it’s nothing.
The extensive U.S. rail network, unlike Europe, is a freight system and dieselized because that’s what’s needed to haul a 10,000 ton drag over a 1.5% grade.
Actually, compared to the heavy haul electrics overseas, US diesels aren’t that spectacular. Slightly higher tractive efforts, but significantly lower horsepower. Nobody offers a diesel with 8,000 HP at the rail, but that’s a catalog item for an electric.
US railroads use diesels because they’re cheap at moving coal, which is basically all railroads in the US are competitive for anymore. Anything time sensitive goes by truck, and has for decades now. A shift away from coal in the US would likely kill a number of Class Is, which is why they’re the remaining big proponents of coal, along with the coal mines (surprise!).
Diesel locomotives use electric traction motors because only electric motors develop torque even when not spinning.…
Actually, electric motors produce their maximum torque at zero rpm. The torque generated is proportional to the current in the motor, and current is maximum when it is stationary. Once the motor begins to rotate, counter electromotive force begins to build in the windings, which opposes the current flow. Because of this, the torque output also decreases.
As a side note, so called dual mode locomotives are becoming more common. These locomotives pick up power from the third rail or they generate their own power via a diesel engine. The New York MTA bought quite a few of these locomotives for the Long Island Rail Road because there are significant sections of track that are not electrified. Since you can’t run diesels in the tunnels, this eliminated the need to switch from a diesel to an electric train. However, these locomotives have been plagued with serious failures. The railroads’s standard electric trains have a 300K miles mean time between failure. The Dual Modes? 12K miles between failures. Manufacturer of the dual modes? General Motors.
” … why not drive the wheels hydraulically?”
Hydrostatic drives like are used on some garden tractors and certain other farm equipment have their advantages, but fuel efficiency isn’t one of them. My friend who used to do a lot of honest to goodness agricultural equipment engineering said that the efficiency losses from a hydraulic drive system are on the order of 20-30%. For some applications that efficiency loss is considered worthwhile, but it wouldn’t cut it for automotive uses.
What a damn fine idea this is – replacing a motor would be as simple as unplug it, unbolt it, take out the driveshaft…. bingo. There would be much fewer parts to go wrong and the internal combustion engine could be pre-set to run as economically as possible. Any car designers out there want to give this a go? Combine this with dynamic braking – it just makes a hell of a lot of sense.
One day a genius is going to harness the most powerful forces in the universe (gravity, magnetism, etc) and electric and ICE engines will be irrelevant. One day…..
@AICFan
First off, tractive effort is where its at on ANY locomotive hauling freight. HP means nothing if you cant get that power to the ground. If you cant get it moving…….. Secondly, anything time sensitive goes by air, not trucks.
While coal is very important to us, intermodal is the future and all class 1’s are moving that way with increased capacity, raising tunnels, new intermodal loading facilities.
It takes around 7 days to get a train hauling 100 trucks coast to coast, with about 34 people crewing the trains, instead of 100 and lots less fuel, with decreased congestion and trucks on the interstates. All that with very little time penalty(yes I know trucks are still prob faster,but not by much)and lower shipping rates for the end consumer.
So to say all American railroads are a one trick pony, is garbage.
I’ve been thinking the same, as well. Perhaps having electric motors compact, powerful, and efficient enough is still an issue. Then you need to waterproof them. Or at least having trucks diesel-electric; for them it should be easier to implement than on cars.
4 to 6 electric motors on the drive wheels, with the diesel running at tiered RPMs driving an alternator controlling the drive wheels and a secondary system handling the driver comfort systems. I wouldn’t mind seeing this happen, and cdotson’s right — fleet managers will literally cry tears of joy when they see the fuel economy gains, which often translate to many $$$ saved on fuel costs.
On the other hand, I don’t see the same thing happening for automobiles. All I see is the slow but steady refinement of both the Prius hybrid system and battery capacity technology.
I think the US Army looked at this for armored vehicles. While diesel electric (locomotive-style) drive motors are improving, so are transmissions. The Abrams has a traditional (although advanced) transmission. So will all armored vehicles in the near future.
That said, given advances and cost reductions in electronics and switches, the ‘tipping point’ toward electric drive train may happen sooner than many expect. There’s inefficiencies and a lot of weight in traditional drive trains.
Armchair engineering is easier than armchair quarterbacking, and even less relevant.
Most armchair quarterbacks have at least played a few games of football ….
Just throw some road wheels on that locomotive in the picture and I’m in. I’ll let the guard rails steer it.
I see several references to problems with GM train engines – GM hasn’t been in the train engine business since 2005. They sold the Electromotive division to private investors (Greenbriar Equity Group and Berkshire Partners).
John Horner :
September 27th, 2009 at 1:13 am
” … why not drive the wheels hydraulically?”
Hydrostatic drives like are used on some garden tractors and certain other farm equipment have their advantages, but fuel efficiency isn’t one of them. My friend who used to do a lot of honest to goodness agricultural equipment engineering said that the efficiency losses from a hydraulic drive system are on the order of 20-30%. For some applications that efficiency loss is considered worthwhile, but it wouldn’t cut it for automotive uses.
Why not at least use a hydraulic accumulator to regenerate energy lost in the braking action, and then use the pressure to get the car rolling off the line.
Trucking is largely done by company trucks and employed drivers and in these applications the driver’s comfort and enjoyment behind the wheel is a non-consideration.
LOL, gawd that’s funny. I’d do damn near anything to keep the normal bitching from getting worse.
Just throw some road wheels on that locomotive in the picture and I’m in. I’ll let the guard rails steer it.
hahahahaha….
Group 7 run what ya brung modified Centenniels!
Formula Coal!
/missing National Lampoon
“US railroads use diesels because they’re cheap at moving coal, which is basically all railroads in the US are competitive for anymore. Anything time sensitive goes by truck, and has for decades now. A shift away from coal in the US would likely kill a number of Class Is, which is why they’re the remaining big proponents of coal, along with the coal mines (surprise!).”
I was a Class One Market Manager for twenty years and I would have to respectfully disagree with you. Virtually every consumer product sold in this country moves via Intermodal (container) from Sea-Tac or Long Beach/L.A. east via Burlington Northern Santa Fe and Union Pacific and that pales compared to the revenue and tonnage still generated from the line-haul of petrochemicals/plastics, imported Canadian lumber, scrap steel, setups (new automobiles and a very big, profitable business) and a massive grain network. All of these commodities are alive and well on rail and will continue to lead the way towards continued on-rail growth.
Not to demean the importance of coal but I watched a $1BB worth of export coal disappear on my Class One in the early ’90’s. It was uncomfortable but was by no means a show stopper. We worked around it and replaced most of it.
I think Giugiaro is working on a design as described by MB Chris, but I can’t find a link.
@ John Williams
cdotson’s right — fleet managers will literally cry tears of joy when they see the fuel economy gains, which often translate to many $$$ saved on fuel costs.
The fact that there are no diesel-electric prime mover trucks should tell you that it doesn’t work out to be more economical (not just capital purchase wise either).
OTH, there is currently a huge effort under way to at least hybridise trucking (well, at Hino at least, MB maybe too). I’m familiar with Hino’s efforts. Light, local area delivery and frequent stopping chassis are getting it first, very slowly.
There are ALOT of low hanging fruit that the big automakers are not selling.
There is a group of shadetree mechanics that built a turbo diesel hybrid in Washington state. Used a VW TDi 1.2L in a Honda Insight. Gets about 100 mpg.
http://www.redlightracing.org/
Like somebody on that website says – they are using off the shelf OEM parts so why can’t the automakers do it?
Saw another one on the web where somebody took a Honda HR-V (think two-door CR-V). Took out the AWD driveshaft (front to back) and replaced the rear differential with an electric motor (one with output shafts at each end). Coupled those output shafts to the rear driveshafts (remember it’s an IRS car). Installed a small EV system that worked in conjunction with the ICE drive. Gives the car the capability to go electric only, hybrid mode, or ICE only.
http://www.evalbum.com/2748
Wouldn’t hub mounted motors suggested by several readers here create all sorts of unsprung weight? A bad thing in my mind.
I suspect the auto industry is somewhat dependent on customers needing costly service and frequent vehicle replacement so I doubt anyone is going to release anything to enables them to disconnect from the auto industry for too long. I seriously think this part of the reason we don’t get more vehicles like the RAV4-EV. Toyota might continue to build them if Chevron/GM had not sued them to the tune of $30M. I doubt many of the other automakers would want the EVs to be sold because the future lost revenues.
They want us to continue to drive piston driven fossil fuel consuming vehicles that wear out about every 200K miles or until we get bored with them and get the urge to buy something different – whichever comes first. Gotta keep the factories humming.
Whatever the case – I want fully battery powered EVs to hit the market for those of us who want them. Let us help mature the technology and fund it’s acceptance.
WHY aren’t we seeing diesel-electric hybrids in semi-trucks? Seems like tech that which would improve fuel mileage 40-50% would be HUGE over a million miles.
I for one would really like to see passenger and freight service return to the USA in the form of electric trains. Let me drive my car onto the train and go cross country at some reasonable price relative to the costs of hotels and fuel for my car.
You effectively describe the Fisker Karma MB Chris.
Generator and two electric motors good for 408bhp.
The Q-drive drive train is provided by Quantum Technologies and was indeed initially developed for the US Army.
“I think the US Army looked at this for armored vehicles. While diesel electric (locomotive-style) drive motors are improving, so are transmissions. The Abrams has a traditional (although advanced) transmission. So will all armored vehicles in the near future.”
As several commentators have pointed out, MB Chris is describing a serial hybrid. Nothing new, either; Ferdinand Porsche designed them for Lohner in 1901. And the Chevy Volt and Fisker Karma are serial hybrids, and works exactly as you describe, except it has one electric motor instead of four.
The serial hybrid is NOT as energy efficient as direct mechanical drive. The losses of the generator and electric motor are greater than the losses of an efficient mechanical transmission. There is no doubt in my mind that the Volt will get worse fuel mileage than a Prius once its battery is depleted, and it’s running from the generator.
Small in-hub electric motors is an area of intense development activity. No doubt we will see some very soon. But they will cost more than using one, or two motors driving each axle. And there is of course, no opportunity to use a gearbox with in-hub motors. There are pros and cons, and over time, these will work itself out.
Having a hybrid gasoline makes no sense at all. That is why, to me, Toyota is a joke.
I just had to step in here and comment due to Pete Moran’s oversimplification of the Prius.
Yes, the Prius, in terms of hardware, is very simple. But Pete always completely misses the point of where the Prius is complex: the software. Searching on the net, I can’t really find much data on the software set, but I will be 10:1 odds that the software running the Prius drivetrain is insanely complex. Lots of negative feedback DSP calculations, lots of tradeoff decision making, and lots of overhead to cover corner cases. Most of that software would not need to exist in a serial hybrid or a battery car. I would bet that most of the Prius budget goes to software engineering and testing. The rest of it warrants NO COST extras (except maybe the increase in copper demand for the motor).
To others on locomotive systems: GE has hybrid locomotives. I believe they are already out of testing and in production, but not 100% on that. They use a molten electrolyte battery to generate up to 2000hp during train acceleration from a dead stop. They have plenty of excess power on board to keep the batteries in a molten state. Not very practical for a car :)
Finally, many commenters here have noted the drop in effiency to go from mechanical-electrical-mechanical. I believe you lose about 14% of the mechanical energy at the input of the alternator between the alternator and the wheels.
Given the incredibly bad efficiency of a ICE motor while cruising (low horsepower, small throttle opening), I wonder if that 14% couldn’t easily be recouped by running a smaller ICE motor at a much higher load (much greater throttle opening). When you need the horsepower, you simply raise the intake manifold pressure dramatically (supercharging of some sort).
I’m sure some professional mechanical engineer has calculated the tradeoffs, but I don’t know if they have published or not, but I think that would be very interesting to know.
Finally, I wanted to say that the Tesla roadster is a incredibly amateurish design — one hopes Tesla is learning quickly at the car design game. Yes, the car is quick, but I don’t think it is even close to as quick as that size car would be with a similarly powered ICE driving the wheels (they claim their induction motor is 248hp — and the weight of the car is really at the lotus level). Furthermore, I seriously doubt their horsepower numbers because of their real world performance numbers: 248hp in a car that size should be much more capable than 125mph top end. If their claims were true — they would have a power to weight ratio of 11lbs/hp. Their horsepower claims sound more like power saw claims: the (I*V/749) when the motor is locked into a dead stall and full voltage applied. It’s not that the car is _bad_, but they make a lot of false or “stretched” claims in my opinion…
Furthermore, I seriously doubt their horsepower numbers because of their real world performance numbers: 248hp in a car that size should be much more capable than 125mph top end.
I would assume that low top end has to do with the car having a single speed transmission? You could add a second speed… but why would you want to?
@Aqua225:
The Tesla isn’t really Lotus weight: A Lotus Exige weights around 2000 lb, whereas a Roadster weights around 2700 lb, or about a third more. The extra weight is due to the 1000 lb battery.
Would a 248 HP ICE get a 2700 lb car from 0-60 in 3.9? The Lotus Exige SC has slight more horsepower, weights 700 lb less, and does it in around 4.1. Also, Tesla’s top speed is limited because they don’t have a transmission, just a single fixed set of gears. No higher gears to shift into.
Tesla’s numbers sound right to me. If anything, it’s an argument in favor of EVs.
I might add that geared and mechanical drive diesel locomotives were used, quite extensively in Europe. The Voith hydraulic transmission was used in pretty much all German diesel locos. Not surprisingly, it was more efficient than the diesel-electric.
Southern Pacific (or some other US railroad) used a bunch of them experimentally to test the concept. The reason it was not adopted was because it had higher maintenance demands on the brutal US Western conditions.
Diesel Electric locomotives were adopted in the US because, in part, of their very reliable and low maintenance demands. It’s possible that may change again someday.
@ joeaverage
There is a group of shadetree mechanics that built a turbo diesel hybrid in Washington state. Used a VW TDi 1.2L in a Honda Insight. Gets about 100 mpg.
Big effort, but frighteningly expensive, really complex and ultimately pointless.
WHY aren’t we seeing diesel-electric hybrids in semi-trucks? Seems like tech that which would improve fuel mileage 40-50% would be HUGE over a million miles.
This is a seriously good question. I don’t understand “why not” myself.
@ aqua225
I will be(t) 10:1 odds that the software running the Prius drivetrain is insanely complex.
If you call managing two variables complex. (Yeah, it’s more complex than that – but, software?? seriously?!?!).
hahahahaha….
Group 7 run what ya brung modified Centenniels!
Formula Coal!
And of course, train drifting!
I suspect the auto industry is somewhat dependent on customers needing costly service and frequent vehicle replacement so I doubt anyone is going to release anything to enables them to disconnect from the auto industry for too long.
And you don’t think that it’s competitive enough for someone to try to release it? And you don’t think that if the auto industry could create a car that didn’t need costly service they wouldn’t just be willing to sell it for more money than the cars that break down? Or that they wouldn’t build it so that they could save money on warranty claims?
And you really believe that car companies are that forward thinking and not short-term thinking that they wouldn’t be willing to sell more cars now in exchange for less parts and service later?
WHY aren’t we seeing diesel-electric hybrids in semi-trucks?
Because at the generally consistent road speeds of most semis, hybrids make no sense. A direct mechanical connection to the wheels is the most efficient. And the extra weight of batteries is a economic barrier for these vehicles.
City trucks, like delivery and garbage trucks, can and will benefit from one type or another of hybridization.
The analog to this hybrid discussion is not railroad locomotives, it’s the diesel-electric submarine. As we all know from “Das Boot,” not to mention the American WW2 sub classics, “Enemy Below” and “Run Silent, Run Deep,” World War 2 vintage subs ran on diesel propulsion engines on the surface and battery-powered electric engines while submerged.
Interestingly, the German U-Boats had the ability to use their diesels to directly drive the propeller as well as to drive a generator. The typical U-Boat (which had two diesel engines) would surface cruise with one engine clutched to a propeller and the other clutched to the generator when it was recharging batteries. For maximum speed, both engines would be clutched to their propeller shafts. (There was one shaft for each engine.) US subs, however, had diesel engines that drove only the generators. The propulsion motors were electric — either fed by the battery or by the generator.
Think the solution would be related to maximizing generation in relation to the ICE. I think that everyone’s assumption is that the ICE connects directly to the generator which powers the electric motor and then the wheels (either directly or through a transmission). It would probably be better to connect the ICE to a transmission and then the generator to maximize electricity produced/RPM. Why couldn’t they add a turbo with a 2nd generator attached (instead of boost, just to spin the generator) allowing for additional production from the same engine?
a turbine engine would be optimal – they work great at one set RPM speed.
Series hybrids typically aren’t used because a full size generator and full size motor tend to be more expensive and less efficient than a transmission.
Generally (not always, but almost always) every time energy is converted from one form to another there’s an efficiency loss. IC is heat to mechanical, and then a complex system to mount the mechanical power to where it’s needed. Series hybrid is heat to mechanical to electrical to mechanical- there’s an extra step in there.
Decent motors and generators tend to have expensive “rare earth” elements in them, which makes them spendy even though they’re simpler and more efficient than normal drivetrains.
If all (or most of) your energy is coming from the engine, just put it straight to the wheels without unecessary transfers. The generator and mtor are mechanically almost the same, and the generator is really only NEEDED for regenerative braking, in which case the motor can be used as a generator.
One way a series hybrid could be made practical is by having a VERY small motor/generator…maybe just enough to sustain 50 mph up a 6% grade…figure 45 hp or less. To go faster up hill you’d dip into battery reserve. The key enabling technology to allow such a tiny engine would be route predicting on GPS. If it knows where you’re going, it could charge up buffer in the battery to climb that big hill up ahead and 75 mph or however fast you’re going. For sustained high-speed cruising, bypassing the generator would still be desirable. Maybe it could have a 1-speed transmission optimized for 65 mph.
The Volt runs it’s battery down to 25% no matter where you’re going, and then has just the range between 25-30% charge to work as a buffer, so it needs a much bigger motor than would be required if it could predict how much energy you’d require over the next 15 minutes or so.
Bruce from DC:
So that’s why the Chevy Volt and the Toyota Prius use the type of hybrid technology that they do. Totyota (Japan) took their cue from their German allies in WWII, while GM(US) looked to US sub technology. The obvious next step is thermonuclear powered turbines providing the electricity to run the motors in the all new Chevy Neutron. As an added bonus, think of how stealthy that will be! I bet Middle Eatern customers would just gobble them up too. They all seem to be extremely interested in nuclear power generation.
FWIW,
MB Chris is on a very functional path.
Navy Labs (and others) have sucessfully executed this concept. With several iterations.
Scalable. With off the shelf componentry. Starting in 1997.
This is hardly science fiction. Google up RST-V. It’s a Hummer, and one of it’s modes is exactly the generator-to-electric-motors-at-the-wheels.
Betwen NRL and DARPA, this project is basically fait accompli.
http://www.spectrum.ieee.org/green-tech/advanced-cars/us-military-goes-for-hybrid-vehicles
Greg
They want us to continue to drive piston driven fossil fuel consuming vehicles that wear out about every 200K miles or until we get bored with them and get the urge to buy something different – whichever comes first.
Sure. That’s why the reliability and longevity of cars experienced a massive increase through the first 100 years of development.
You are right about one thing, though: most people do get bored of their cars after 100k or 200k miles. This is a good part of the reason why most cars don’t any longer.
And why aren’t we seeing things like that electric HR-V or TDi Insight? Because most manufacturers would go out of business if they spent so much development money on a niche vehicle, or they would be sued out of existence for hacking together a magnet for ambulance chasers.
You would need a source of funding that is, theoretically, bottomless. You would need a backer to keep your business running no matter how much time or money spent on the project. You would need some way to sell your outrageously expensive (to develop AND sell) product at an artificially low price while still, technically, making money. You would, I think, need to be General Motors.
Daanii2, that is the answer I was looking for. I don’t need all the details about how or why a locomotive is built the way it is. I already know all that stuff. thalter, I didn’t know the Volt had an ICE as well. I thought it was pure electric. Lorenzo, I agree with you on doing away with the ICE altogether. I was talking in the short term. In my reading I’m seeing articles saying the hybrid is a stopgap measure till fuel cells can be made cheaply enough. Unless there has been a breakthrough that isn’t supposed to happen for a decade or two. You can never tell with technology. What I’m envisioning is an electric vehicle that just has a small ICE (larger than that in the Volt) for battery charging when needed. With currently available electric range you could commute and drive around most of the day purely electric. Plug up at night and recharge. The ICE is there to prevent you from running out of power and for long trips so theorectically wouldn’t be used much. You get the advantage of a purely electric vehicle with the convenience of a current vehicle that can travel across the country. — Only using less fuel. The barrier really is the fear of change among consumers. Current hybrids are really nothing more than expensive experiments trying to get a market going in the direction of electric vehicles.
MBChris,
Like I said, the electric scenario you’re asking about has been done. Not for public consumption, but it’s already out there.
The future of hybrids (for mass consumption) is pneumatic. Much cheaper than electric, and much less engineering required. Hydraulic is too expensive.
(And yes, NRL and a coupla others in the alphabet-soup, have successfully built and operated them too.)
http://wardsauto.com/ar/gm_fuel_cell_090924/ Well this is the best news I’ve seen so far on the quest toward fuel cells. Porschespeed, if the current crop of hybrids is the cheapest and the best they can come up with so far, I’ll pass. Takes too long to pay back the upfront costs of the hybrid system in fuel savings. Consider me politically incorrect in that I’m interested in the cheapest mode of transporation and not the greenest.
@ MBChris,
Current hybrids are really nothing more than expensive experiments trying to get a market going in the direction of electric vehicles.
Consider me politically incorrect in that I’m interested in the cheapest mode of transporation and not the greenest.
These two statements tell me that you asked a question and then were only satisfied with an answer that fit your preconceptions. Well done.