Diesel Electric Motors for Passenger Cars

I think it's been/being done already... a small IC engine can be run at optimum efficiency to drive the generator... which then gives you electric power.

Del

Any conversion of energy forms, such as using a diesel engine to drive a generator to charge batteries/drive electric motors, inevitably involves losses.

The reason it works in diesel-electric trains is that the energy lost is less than would be lost by the complex gearing necessary to keep the diesel engine running at an efficient speed (engine rpm) over the range of speeds at which the train runs (wheel rpm).

I'm very familiar with diesel/ electric locomotives and a scaled down model to operate a car or small delivery truck SHOULD be possible. No transmission, direct drive, just like on a train. The reason for the 3000 hp engine is the load the loco has to pull. A car SHOULD be much less problem. The problem is it's not technical enough to keep the design engineers at the big 3 busy. It's probably so cheap half the factory would lose their jobs because it's to easy. Think about this. More complicated more people, less complicated less people.

Happy Trails

jazz

There are currently commercial versions of cars that use electrically assisted engines with regenerative braking, like the Prius. They do not use diesel, but use a smart concept making the engine work in Atkinson cycle instead of standard Otto. And have a very nice scinoptic panel that shows the power distribution "on the fly".

I agree there are not so big deals with the idea. I'd add that the engines should also be located in the wheels to minimize transmission losses and serve as integral power drive and brakes.

The most difficult thing to do? A good power storage system, environmental friendly not only during working, but also for recycle and disposal. Batteries as we know them today widely used in cars are not good options. They are heavy, have short life, and are a kind of complicated to recycle, if you think that you may need a dozen to make a car move with autonomy comparable to a fuel tank.

150 million diesel-generator-motor sets? That's full employment for at least a million emi/emc engineers.

This is twice you've referred to forum members as "Know it alls". I suspect you may have a native language other than English since that's normally a derogatory term.

Being a desendant of the conquering imigrants of the world that have invaded this continent and been part of what has made it the BEST and having been doing that in this country for 57 long years and contributing what I have and having the constitution backing me up I have the right to Hang with the people I want to and I wanna hang with the "know it all's, Like people usually gravitate to the Knowledge Whole.

jazz

No problem. I don't usually see it as a compliment, but I am happy to see a new face hanging out here.

I try to think out of the circle. Much better view.

jazz

The idea makes sense. The big three have been talking, but not loudly. My prototype, which is currently languishing for lack of funding, operates on the principal you have summarized. The Chevy Volt will do the same, and is a series hybrid too, despite Chevy's claims to the contrary*. Aptera will eventually have a plug-in hybrid version of their EV too. I'd guess there are about 15 or 20 cars and trikes coming out fairly soon (unless the businesses all crash) which will be plug-in hybrids. The first series plug-in hybrid was the 1903 Loehner-Porsche.

For my small vehicle, a diesel does not make sense from a cost or emissions standpoint. An Atkinson cycle gasoline engine is very close to diesel efficiency, without the high fuel cost. A series hybrid has an advantage (over a parallel hybrid, like a Prius) in city traffic, because the engine never runs under light load, and therefore runs efficiently, or not at all. However, on a trip, at a constant speed on a level road, a strict series hybrid is less efficient than driving the wheels more directly. Chevy does not seem to be planning anything to overcome this shortcoming. Mine will have a selectable direct-drive mode.

*They claim it is an electric car, and that therefore it should be treated (for CAFE purposes, and window sticker purposes) as such, which per current law produces a much more favorable MPGe (mpg equivalent) number: over 100 MPGe. As a hybrid, it would be rated at about 45-48 MPG -- no better than a Prius. Obviously, any car which is propelled by an electric motor, and which has a gasoline motor on board to recharge batteries or drive the wheels directly is a hybrid. The Volt is very often cited as an example of a serial plug-in hybrid. But some people in the press have bought into the GM preference for calling it an electric vehicle, which I think is nonsense. If it is an electric car, then it only has 40 mile range. Try to sell that for $40,000. If the engine starts to recharge batteries (and feed the electric motors directly) it is a hybrid -- there is no question. It is either unmarketable or a hybrid -- you can't have it both ways -- but maybe GM will be able to use some of the bailout money to pay lobbyists to rig things.

I'm not a college educated human being but I do have alot of hard knocks classes under my belt. I've been riding Harleys and working on my own cars, trucks and motorhomes for more than 45 years and in that accumulated experience I've determined that with the right combination of internal combustion engine, Gas or diesel, stoage battery system and electric drive motors, no transmission but direct drive, there has to be a system that will work for smaller vehicles than trains. When the engineer pulls the lever for power the diesel engine powers up to provide electricity for the direct drive motors. If on a long straight ride in a car the batteries would take over until the on-board computer starts the diesel/ gas engine to charge the batteries and power the electric drive motor/ s. Cigarett lighter is an option. Let's not make this project any more dificult than it is. You must be on the right track if you already have what ya got. Is that a picture of it. To all readers, please respect the english language. Proof read before submiting.

Is that a picture of it.

Yes, sort of. The picture is of the proof of concept prototype, which is quite a bit smaller than the eventual production version. The production version will seat two in tandem, rather than just one as in the picture version. (details here)

Eliminating the transmission is a good idea, although you will find that only AC motors really lend themselves to this strategy, because they have unusually high torque at load speeds. Even with AC motors, the combination of the motor and a two speed transmission generally works out better than a single speed transmission. (The Tesla originally took this approach, but they couldn't the transmission to work !!?? -- it's not new stuff -- so they are now using a single speed. Top speed, already low for a "super" car, is now even lower.) A two-speed (or CVT) gearbox allows the motor to be enough lighter to make the whole package work slightly better. For some motors (permanent magnet DC, for instance) a transmission is essential to get adequate hill climbing abaility, but also a resonable top speed.)

Here is a link to a car not unlike the one you describe.

The Germans are on the case... just sit back a wait

http://rb-k.bosch.de/en/powerconsumptionemissions/dieselsysteme/dieselknowledge/dieselhybrid.html

25% more fuel efficient than a simple current diesel engine

btw.. The Atkinson cycle and Miller cycle only compensate for the inefficiencies of the traditional crank design so less energy is wasted.

I've witnessed the Bus they have and are testing in Europe now let's get down to car size. I can see a small 4 cly diesel or gas engine that drives a generator/ alternator motor that powers the front or rear wheel direct drive electric motors, Just exactly what a train has only MUCH smaller. What's the big deal. Watch a train and understand what's happening. It's very simple. It's train technolgy, not rocket science.

jazz

The hydraulic system sounds interesting. You could use something like a variable swashplate for control. Verrry interesting.

Hydrolic or electric what's the difference?, Well one will electricute ya and the other will drown ya. Just be grownded or wear a life vest.

jazz

Hydraulics, if you can solve the efficiency vs cost problem, doesn't have many side effects. Electrical control maybe does (see IEEE something or the other volume that looked at this - sorry I don't remember the vol). I assume we can solve all the emi/emc issues, but we still have the problem of large-scale battery manufacture/disposal/recycling. Not impossible, but maybe more difficult.

And, I think it'll depend on the type of vehicle and the type of travel. I'm betting an intraurban trolley will end up different from a two-person interstate vehicle?

I'm betting an intraurban trolley will end up different from a two-person interstate vehicle?

Definitely. For garbage trucks, where almost all the time is spent accelerating or decelerating, then the relatively (albeit potentially) higher efficiency of hydraulic regen can be beneficial, and the additional mass is less of an issue. (The energy consumed in overcoming rolling resistance, in this application, would be much less than that consumed in acceleration and deceleration. The accel energy and decel energy balance out -- more or less -- regardless of mass.) However, even this is not necessarily an advantage of hydraulics. It used to be that supercaps were thought necessary to capture high power braking energy, (with batteries being OK only for gradual deceleration) but now, some of the lithium chemistries will accept very high charge rates. In a garbage truck, batteries would need to be water cooled*, but hydraulics would likely require at least a fan-cooled heat exchanger.

* I'd guess losses at the batteries would be about 10% at high charge rates. This is pretty low, but when the power is high (as it is in braking) it still would result in a fair amount of heat.

I understand that UPS has a research study going on using hydraulic motors for braking, to charge a holding tank, then use that pressure to help with acceleration, not continuous driving.

Given all the stop/start that UPS delivery drivers do, I can see where it could help them out a lot. If it works out for them, USPS and FedEx, even city cabs, could benefit.

Balancing cost vs benefit (better mileage, better emissions, extra weight and things to maintain, capital investment at a reasonable rate of return, extra mechanic and possibly driver training, etc)

I am guessing that Hydraulics might be a little more 'off the shelf' kind of solution than doing it with pneumatics, or weights, pulleys and levers!

Great answer, Seaplaneguy.

That diesel electric train could be done in the hydraulic domain just as well as with electric motors. There is no magic to electrics.

First, of course there is magic to electrics: There is a radio station 20 miles away, and I can hear it just by sticking a hunk of wire in the sky, and connecting that wire to an earphone through a diode. That's more magical than the stuff that David Copperfield does, by a long shot.

The trend in haul trucks (those 400 ton payload trucks used in mining) has been toward electrics and away from hydraulics for traction power. (These machines, like trains, have been hybrids for decades.) The problems with hydraulics are more pragmatic than theoretical. High-efficiency variable displacement pumps are costly. Smooth noiseless control is difficult to achieve. (I've never driven a hydrostatic transmission vehicle that could be as smoothly changed from speed to speed as people expect in a car. Electronic dithering of valves in the control system helps, but adds cost and complexity.) Lightweight energy storage is effectively impossible to achieve with hydraulics: the UPS hydraulic hybrid trucks store a tiny amount of energy (using about 2000 lbs to store about 1/3 as much as a Prius battery does in 88 lbs) The UPS trucks are research vehicles built partly with tax payer dollars, (and therefore, without much regard for economy) and even then, look stunningly poor in terms of energy storage.

Meanwhile, the cost of lithium-X batteries keeps dropping and capability keeps improving, to the extent that I can buy, today, batteries that work well for an acceptable price ($500 per kilowatt-hr). This price means that plug-in hybrids could be produced today at reasonable prices.

Ken,

Radio, yes, "magic"...

Innas from Holland has some interesting hydraulics.

A Scotish company called Artemis has a radial motor that has NO noise. BMW 530i Digital Displacement Hybrid video

I read in a blog where one of Artemis's engineers confirmed that they have NO noise...why? Because they close the valves correctly, unlike the axial piston motors and most other designs.

All of the axial pistion motors have noise because they continually compress and decompress the fluid (3% each time). None of them are acceptable for car useage. The UPS project uses these types of motors from Eaton, and Eaton is using the EPA to promote their products with little innovation in sight....

The point being, if there is the development in hydraulics like there is in electrics, hydraulics could ( in my opinion "will") have an advantage when you consider a total system synergy with a "new" thermal cycle.

All of the Electrics do little to improve the thermal cycles, and a car is a thermal envelope, not a radio or electric envelope. Think of "combined heat and power" and you soon realize that power loads for keeping the car warm or hot become a large part of the loads once the system losses are removed and 60-70% chemical-to drive conversion is realized with proper thermodynamics. Electrics are a bandaid to the problem, and I believe will be less efficient, heavier, and much more costly long term.

Electrics is for control and brains, not power. It allows for many connections and switching logics. By combining the thermal power cycle with the environmental control cycles (which nobody I know of is trying to do...), you can kill two birds with one stone. How do you get cold/warm air with electrics without all the added pumps and cycles? Thermo-electrics are very very inefficient.

In any case, no hydraulics I know of, excepts the Artemis motor, is even close to what is needed. Hydraulics is like where electrics was in the 1979 article linked above. And in the end, I don't want to be hooked to a grid...running on coal...

If everybody plugged in their car and was captive to the grid, what price would a kw-hr be compared to gasoline? Coal is about 20 cents/gallon equivalent (10.5 lbs of coal is about a gallon) and with (your figures from previous posts) 3 times factor, you have 60 cents per gallon for electricity for fuel. If you take 34.7 kw-hr/gallon you have a fuel cost of 1.7 cent/kw-hr, but they sell it at 7 cents! $0.07x34.7=$2.43/gallon. Electricity is NOT cheap. The Artimis motor is 97% efficient, which is better than most electric motors at their best.

The thing most people forget is that if you want to get to hydrogen, you need tanks. Hydraulics and tanks go together, electrics do not. An engine I am looking at/developing will NEED tanks to get 60% efficiency, and when you couple that to the already achieved 2x improvement of the Artemis system, you get a 4xs improvement over current fuel consumption, which leaves electrics "short" a bit (pun intended).

Thanks again for the good comments Ken... The debate continues...

Seaplaneguy

There is one factor which should be focused on that maybe has been overlooked or sidelined. An IC engine is a converter, converting energy stored in a liquid form into energy in the form of rotational motion.

Unfortunately IC engines are invariably made from materials that chuck away a great percentage of the heat energy after it is extracted from the liquid fuel. Ultimately we are forced to limit IC engines' running temperatures [efficiency] to the maximum the engine oil lubrication can withstand.

Keeping this in mind, it might be possible to use an engine with a far larger cubic capacity than would normally be used, so that it can be run in combination with hydraulic accumulators in such a way that it would need a minimal or no cooling [energy dumping] system at all.

Basically, when the engine is off it needs to be insulated and kept warm. And when it is running in the urban cycle, it needs to generate enough power to drive the car and fill the accumulators before it generates enough heat to overheat.

Cooling at high speed should not be a problem as there is a ready supply of high-speed cool air. An auxiliary electric fan with a ducting system could take care of exceptional conditions.

Your comments please!

Mr. London,

Yes, an IC engine should be "insulated" IF it is designed correctly. It is, after all, a thermal engine.

Insulation can be achieved via air held exterior to the combustion wall that can insulate as needed during low to off power times and let it open up for high power (if needed), eliminating the insulation, as it were, during these times. Call it variable insulation... Water, as in most car engines, would have to be held at high pressures to do this, requiring an accumulator and high pressure pump. There, then is a problem with the oil film...and so on and so on. A typical piston head would not likely work from where I see it.

The more I look into this, the less it looks like a convention IC engine. I have not found ONE part from an IC piston crank engine that I can use on my new engine.

If you look at the basic equation for thermal efficiency 1-TL/TH, (ex. 1-300k/1500k=.8) you realize that you can get 80% by only going to 1500 kelvin where N2 does not breakdown. Clearly, cranking up the temperature may not be a good way to go, when other things are considered.

The more I look at this, the more insulation I want, which seems logical.

Seaplaneguy

Looks like we may be thinking along similar lines as far as redesigning the IC engine then. Poppet valves and cams are nasty and traditional cranks cause big problems and are inefficient. Materials used where the heat is [compression and explosion etc] should be very different to where what ever replaces the crank is, as they are doing different jobs.

As I see it, there are two types of designers; tinkerers [tinkering with existing designs] and re-thinkers [maybe the design was never right in the first place or new materials and systems are now available to the designer]

Good luck with your engine!

BTW 1500 Kelvin = 1227°C which is hot enough for me

Ken,

Thanks for the updated values and pointing out the distortions in the Artemis quotes.

I calculated 1:10 ratio for air:battery energy density based on a much larger tank (20 gallons CNG /72 gallons volume typical in a CNG car). That little thing they show is bit small.

A point not made is the fact that hydraulics accumulators are time dependent. If you stop and start, the foam insulation (as used in the UPS accumulators) keeps the heat transfer to a minimum, and hence makes it adiabatic (heat transfer=zero). If you wait a while that "efficiency" can go to 50% when the gas inside is ambient and when expanded thereafter quickly, the gas cools and output can be a mere 25% efficiency or so. A battery does not do that.

I don't use my tanks like they do...synergies...

Another point is that electricity is currently a one source/single type monopoly "fuel" shop. I quoted $0.07/kw-hr, but most places in the east coast are 2-3 times ($0.14-0.21 /kw-hr) that figure, or about $4.85-7.28/gallon-e, based on 34.7kw-h/gallone (your figure). OUCH! (If you use the LOW heating value, which is 10% more than the "high" heating value of gasoline, my figure with gasoline at 125,000 BTU/gallon for gasoline high heating value is 20% higher than yours. My engine uses the low value...so for me there are 40.3 kw-hr/gallon)

In comparison, with a multi-fueled engine like what I am doing, I can use CNG, Propane, Gasoline, Diesel, oil, Coal gas, most bio fuels, hydrogen, and uncompressed natural gas (the engine will compress it if wanted). I just choose the lowest cost per BTU... Most will be run off of solar based hydrogen, which requires, again, tanks... So, I may not need to fill up only a few times a year when the weather is bad or a trip is long or at night...

To boot, I have long-long term energy storage via hydrogen generation. If I drive to Pike's peak down to Denver I can store it as hydrogen after I max out the pressure and hydraulics, and do so with a 50-70% capture efficiency.

I can't see how to "cover all the bases" with electrics without non synergistic sub systems. With hydraulics I can be "free" to a large extent and go where the costs are lowest and not in crisis mode manufactured by some cartel (electric utility or OPEC).

Last but not least, would you buy a "used" battery? I would buy a used accumulator or CNG tank. The value of a battery drops off a cliff once the wrapper is gone. Anybody with a cell phone knows this...

So, the shortest distance to telling Al Gore and company to take a flying leap is to go the route I am going. Freedom baby! No to a NWO. NO to co2 tax. NO to the UN. No to crisis manufacturers. No to the endless treadmill of worn out cars...

Which leads to a roadable VTOL seaplane... Now we are talking performance!

Seaplaneguy

I can't see how to "cover all the bases" with electrics without non synergistic sub systems. With hydraulics I can be "free" to a large extent and go where the costs are lowest and not in crisis mode manufactured by some cartel (electric utility or OPEC).

I agree that electric hybrids are more compensatory than synergistic. Your engine system sounds pretty interesting, and as you get to the point that you can make a full disclosure I'd like to hear more.

Last but not least, would you buy a "used" battery? I would buy a used accumulator or CNG tank. The value of a battery drops off a cliff once the wrapper is gone. Anybody with a cell phone knows this...

Yes, batteries are pretty much done after the fat lady sings. However, there is a market for used lead acid batteries after they have been used in fork lift trucks. People will buy them for stationary use, and get another 5 years out of them. The NiMH batteries in the Toyota RAV4 EV have been lasting for a very long time: 125,000- 150,000 miles. These batteries "should" be $10,000, although some people have paid $26,000, a staggeringly high figure, adding 20 cents cost to each mile. If something like the Volt (or better yet, something aimed at a broader market) comes out (making good batteries a mass production item), then a LithiumX battery pack for something like a RAV4 could be $5000. That puts it pretty much in line with an engine replacement, and if you added up the savings from not having to change oil, an electric vehicle would be pretty close in cost to a gas vehicle.

Cut the range in half, and the electric vehicle looks more attractive, from a cost perspective. If you cut the range even more but then add a small engine for range extension, then the economic deal looks very good. If you get fanatic, and make the vehicle small, light and streamlined, then operation becomes downright cheap. Make such a vehicle inexpensive to buy, and I think there can be a good market for it.

I think your approach can work well too, although it's a bigger project than I would want to undertake.

GA Ken, now someone else give him his century.

Mercy buckets t' yuz guyz!

Quite right. A diesel electric extended range hybrid would be quite nice. But trying to size a straight diesel electric for a car would be a bit of a problem because of the weight compared to a gas engine.

You want a locomotive to be heavy and they tend to run at more steady states than a car in traffic would. The car is going to be changing engine speed a lot and wants to weigh less both for handling and fuel consumption with all the accelerations going on.

It's never been commercialized. Maybe hybrid systems will change the rules.

Since diesel cars get much higher mileage so they are almost 'standard' in europe, or at least common.

They are not on this side of the Atlantic because of emissions. At one time the excuse was sulfur, but the diesel on sale now is sans-sulfur (for the most part). If I remember right is the NO or other nitrogen compounds that are supposed to be why the US doesn't have diesel cars available anymore (some are here, but none from the Big3 - and Ford is supposed to be selling now or next year a 80+MPG diesel car - if my memory serves me right, but not in North America!)

The reason why there are not many diesel cars in the US is to do with fuel taxation not pollution or emissions. If diesel emissions were that bad all the trucks would be petrol/gasoline too

The latest European diesels such as the 3 cylinder VW Polo are probably the cleanest cars with internal combustion engines. They also have particulate filters and the Next Generation of filters will trap even finer particles.

Interestingly, the BMW diesel mini engine, which was a joint-venture with Peugeot is less polluting than the Toyota prius.

You may not think so, but fuel prices in the US should be double what they are to reflect the true value, scarcity and damage done to our planet by burning fossil fuels.

Actually, emissions is part of the reason there are few diesels here. VW stopped selling diesels here for that reason, and now, with new emission controls, are once again bringing in diesels. Emission regulations for trucks have been more lenient than for cars here.

That emissions hurdle, however is not the main reason diesels don't sell well here. For many years, we've had the VW TDI-engined cars, (and Mercedes diesels) and they do everything well, but don't sell well. Part of the problem is initial cost, with the difference in fuel efficiency not being great enough to make a significant difference in the typical 3-year buying cycle (which is itself pretty crazy). Another is the high cost of diesel fuel. Yet another is the perception -- diesel fuel smells bad, is not available every where, and is associated with trucks and truck stops, neither of which are held in high regard.

Can you clarify the first part of your statement please? Are you referring to 1980's Diesel VW Rabbits or the TDI's produced in the last 10 years?

I have just calculated the average cost of petrol/gasoline and diesel in the US and UK.

Petrol works out at $1.699/USG [44.8 cents/litre] and $5.05/USG in the UK [$1.335/litre] so that's nearly 3 x cheaper in the US.

Diesel is $2.515/USG [66.44 cents/litre] and $5.83/USG in the UK [$1.54/litre] so that's 2.32 x cheaper in the US.

Noted that in most other European countries diesel is cheaper than petrol/gasoline.

Also note that European diesel does not smell any more at least no more than heating oil; don't ask me why they used to put the smell into diesel fuel and why they've taken it out now.

So it appears that there is a price differential and an image problem with diesel in America which could easily be solved by increasing the tax on gasoline and encouraging more diesel refining [which is a major factor in the high price of diesel]

Now THAT sounds like a solution from a welfare state, if you'll allow me to use an inflamatory term, where I can't think of one more accurate. Sure, make us all wish to use more diesel by INCREASING our costs of living, and do that by adding more taxes on to what we have to buy, when we all know that the ones doing the taxing (Congress) bring absolutely NO value added to the processes of production, distribution, storage, or any other facet of the effort. Why, oh, WHY, should we WANT to give more money to those wastrels?

Yep, that is what I heard in the 'promises' section of the last election.

It was just as good as the folks coming out of some stadium style political jam session saying how Wonderful it will be, she won't have to worry about loosing her house, or car, or keeping a job this 'lady' didn't like, because the now current president-elect was going to 'fix it' all. ... All I could do is shake my head.

I guess we did not learn from the Romans about giving bread and circuses and not governing for the real benefit of the people. Eventually the folks will revolt like the French did after some comments about 'Let them eat cake' after rioting because of lack of flour for the masses while the elite lived in relative luxury.

I know the Declaration of Independance is a founding, but not official document of the US government. But it starts seeming like it is getting to the point were it may need to be involked again. ... Like pressing cntl-alt-delete on a M$oft government. I do not endorce that action or suggest it is a good thing, and restarting a government is to be avoided as much as possible, but this great governmental experiment may need it to be done to get the people back in control.

Well the American people voted two elections ago for a guy who invaded a sovereign state on the other side of the world and suddenly all his friends companies seem to have rather a lot of lucrative contracts funded by the American taxpayer.

On a more serious note, we all know the whole planet and especially organised religions are corrupt, but a certain degree of management/control/governance is necessary if things are to run reasonably smoothly. That control has obviously been lacking in the US in recent years.

The European Union has encouraged and managed the development of diesel powered cars so now we have cleaner burning engines and almost odourless diesel available at every service station where you can buy petrol from. With the new particulate filters used by Toyota, VW, Peugeot etc and the engine management systems, these diesels are very clean and much nicer to drive than their petrol counterparts as they have higher torque output for a given cubic capacity.

If every car in America was diesel the fuel used would be reduced by approximately 30%.

When you factor in the wasted mpg of a gasoline/petrol engine compared to the more efficient diesel engine, the price of 1 USG of gasoline/petrol is in effect $2.20

Are you referring to 1980's Diesel VW Rabbits or the TDI's produced in the last 10 years?

The TDI's produced in the last 10 years. They were seen here in mainly in the Jetta and new Beetle. Then they were unavailable for 2007 and 2008 model years (roughly) because they would not meet emission standards. Now, they are equipped with (I think) both urea injection and particulate filters (similar to MB Blu Tec) so are once again legal for sale here.

I have no experience with diesel/electric motivation but I imagine that weight of this system (when compared to an engine only) is not much of an issue for a traction engine, since they need to be heavy to pull large non-powered loads. It likely is a factor in smaller vehicles.

This is something I'm sure the hybrid drive train people are working on.

I believe the main reason for the diesel electric powered trains is for the traction. The diesel powered alternator powers an electric drive motor on each axle. If they put 4000 HP to one axle it would just spin its wheels.

Diesel electric cars are a novel idea. If the engine could run at a constant rpm at its peak efficiency and charge batteries or capacitors at low demand periods to be used at high demand periods, one would think it could operate very efficiently. I would be concerned about the added weight of the alternator-electric traction motor-battery/capacitor over the weight of a diesel mechanical drive system. Would their be a net gain?

In 1978 I wrote a paper as a closeout to an Individual Studies Project at the University of Northern Iowa. The study model was a Regenerative Capable Switching Locomotive. The paper was pretty rough but it did explain some of the basic principles. Its available in PDF format if anyone cares to peruse it. In 1984 I entered the Rolex Awards competition with an regenerative capable hybrid automotive proposal. That is also available. Simply send me an email requesting either or both. mjcarter01@aol.com

I also re-wrote and re-designed a concept for a C. N .Okoye who claimed to be a student in China at Harbin Technical Institute. His study was of a Hydraulic Hybrid but there are many parallels with a ICE/Generator Regenerative Capable Hybrid. Although Mr. Okoye never shared the finished product with me, that part that was rewritten by me to include the power flow diagrams is also available upon request.

Here is a link to a little pop/science type essay I wrote regarding "The Three Fundamental Efficiencies of Hybrid Technology." The first of these efficiencies is Power Averaging which brings a number of efficiencies to the forefront. This first fundamental efficiency is still absent in available technology. This essay can be perused at http://www.bestsyndication.com/Articles/2006/c/carter_mark/031206_hybrid_cars.htm

Please try to look past the title and introductory sentence. I had some help with that screw up.

My dream hybrid incorporates those three fundamental efficiencies, has four wheel anti-skid/slip drive provided by regenerative capable wheel integrated traction motors, and very high acceleration provided through the application of the third efficiency .

In any case, the industry isn't there yet. I think the technology is there, its just a matter of time before the engineers put the puzzle together.

Anywhooo. Thats all I have to offer up on the topic.

Gavilan

Gavilan,

I read the article and was left with a question: What is the 800 lb fly in that room?

My Answer is: Duty cycle.

Most all engines have an efficiency curve that peaks around 75% of peak power and goes way down at 1%. The typical car with 200 hp may use 5 hp at 25 mph in traffic, where the motor is 5% efficient, not 35%. Herein is the issue not really discussed.

Question: If you design the motor with a constant efficiency, what is left with the article you mentioned? (Innas.com says their engine is "constant" in hydraulic output, and so does Sandia Lab's free piston engine that generates electricity)

My answer: regenerative braking. Peak power is not an issue if the engine is constant efficiency. No? No leveling needed. No? With regen braking the weight of the vehicle is conserved in stop and go. Hydraulics does this best to date.

The key, in my opinion, is the synergy of all in one whole system. Sacrificing efficiency for regen braking does not make sense. Each needs to be considered. The power delivery density, or the ability to give and take energy at a high rates is 40:1 in favor for hydraulics over battery electrics, and the power density of the motors is 8:1 in favor of hydraulics over electrics. In a world where weight matters, hydraulics seems to be much better.

Last, can you say more about your view of things? You seem to have thought a lot about it...

I like the idea of the driver telling the car to get ready for a hill, up or down, or a stop. In an accumulator hydraulics system, one would fill the tank up when slow and keep it low when at speed in order to have room to capture energy. If a person wanted to pass, they could tell the accumulator to fill up even though the car speed is 70 mph, where it would normally be lowly filled, for example, and use that store to pass. The difference in tank top to bottom would be 0-100 mph in quick energy recovery, for example.

Then there is the quick versus long store (long down hill grade) ability that would also come into play. For example, if an electric car had some measure of capacitance (capacitors instead of batteries) equal to 0-100 mph recover, and then uses battery for long grades, it would lessen the cycles on the battery and capture those quick braking events that could be passed over to the battery over time, better conforming to the battery physics of low energy acceptance rates.

The system I am working on has both quick and slow ability...because each has a synergistic advantage in certain areas.

I e-mailed you...

Thanks

Seaplaneguy

Hi Mark,

Good clear article. Hybrids differ in the degree to which these efficiencies are pursued. At the laughable end is the Chevy Malibu hybrid, which gets worse mileage than my 2004 four cylinder Accord. It has both insufficient generation capacity and storage capacity for good regen, and meaningless additional peak power capacity. If ever there was a cynical attempt to pretend to have a "hybrid" ...

The Prius has a meaningful storage capacity, so is better able to exploit hybrid advantages. Interestingly, at the same time, the efficiency of its engine is substantially better than that of most cars, and its efficiency spread is also much better, so that even without the hybridizing, the Prius would still get very good fuel efficiency (by virtue of the engine, low rr tires, transmission efficiency, and good aero.) (The Prius does a reasonably good job of capitalizing on the sort of synergism that Seaplane has mentioned.)

When the energy storage capacity becomes large enough, (as in the Chevy Volt) then regenerative braking efficiency improves. In my MC2, the controller and motor ratings (rather than battery acceptance rate) are the limiting factors on regen, (because the battery bank is large enough for 30-40 mile range on the grid, which in turn means it is large enough for good charge acceptance).

This large storage capacity leads to a further "efficiency" (loosely put) that your article did not mention. There are many ways of obtaining electricity that are more efficient than the grid mix. Even taking into account the fairly high environmental cost of solar cells (for example) most are to the point that they are more efficient, on a full life cycle basis, than the grid mix is. Home based co-generation, in which (what would otherwise be) waste heat from a generator is used to heat hot water, can be highly efficient: up to 85% or so. In such a system, you'd power a generator with natural gas, charge you car and heat domestic hot water. (It happens that the numbers work well for a family of four and a typical commute, so you are not throwing out excess hot water.) Electrical storage has the advantage that electricity can be generated in so many different ways. Thus, it is simple to effectively power your plug-in hybrid on coal one day, natural gas the next, hydro the next, and nuclear the next. (Obviously, one does not have day-by-day control over the grid mix, but the concept is applicable: we don't see people waiting in lines for hours to get electricity, as we did in the Atlanta area for about a month, recently.)

So the possibility of storing large amounts of energy is an additional "efficiency" of a hybrid*, because it allows you to use many different fuels and fuel substitutes. Hydraulics, although potentially efficient for light hybridization (where the only energy stored is for one regen-accel cycle, a regime in which batteries are poor if sized according to energy capacity rather than power capacity) for in-city use, falls apart completely when the amount of energy to be stored is large enough to permit a wide selection of energy sources.

That said, I'd love to see Seaplane come up with an integrated system which exploits hydraulics. If such a system can quadruple fuel efficiency (and I agree with him that this is not impossible) and be offered for a price only slightly higher than current offerings, then many of our energy concerns would disappear.

* One could argue, incidentally, that all the existing production hybrids are not really hybrids, in that all the energy used for propulsion comes from a single fuel run through a single engine. It's interesting that GM is trying to argue that the Volt is not a hybrid from the opposite angle: they say it is a pure electric vehicle, which just happens (gosh, golly) to have a gasoline engine on board to recharge batteries and supply energy directly to the drive motors. For this to be remotely believable, they would have to say that the the vehicle in not intended to both recharge batteries and be driven at the same time. If that were the case, then the car would be woefully under-powered after the batteries die, and until you plugged in at night: there is no direct motor-wheels connection, so an underpowered engine driving through an electrical controller/motor system that adds an additional 10% loss is not realistic for customer acceptance. On the other hand, if it operates as a real hybrid, charging the battery bank when possible to restore peak power delivery, then the vehicle becomes attractive. Unfortunately, many people will swallow their story, I suspect, which will allow them to claim that the Volt gets 150 MPGe (because the current proposal for rating electric vehicles uses a pump-to-wheels standard (34kWh/gallon). If a vehicle is an electric vehicle, then MPGe should not be used, because it is misleading and unnecessary. Just quote the real energy usage, which will be about 300 Wh/mile for the Volt, if it is really as inefficient as has been claimed. Operating cost is then simple to calculate, based upon what you pay for electricity.

Ken,

If you read my last post, I think we are both thinking along the same lines of multi-fuel. You are saying go electric because you can get it from wind, solar, gasoline gen, diesel gen, etc., and store it in a battery that is 10-40 times better than an air tank. Agreed.

I don't think I mentioned it, but my engine will run off of resistive heat...so I can also use a battery if batteries are the best technology. I say, if in Mecca, don't sell pork...let them eat kosher cake...

To take a nice shower takes about 15-20 hp, or about what it takes to run a 3500 lbs car down the road at 70 mph. My house fuel usage is 1500 gallon e of NG per year, or enough to drive 37,500 miles @ 25 mpg. If you want to tackle fuel use, a house is a great place to start.

My approach takes in the heating and electricity of a house or building, not just a car or airplane. A car is a small mobile home that likes to use lots of power. Both have solar...

Ken, you would know...

What would a 400 hp electric motor weigh? Artemis says 0.1704 hp/lb. What is your figure?

My needs are:

100 hp prime mover, 100 gen, 400 electric motor, battery to make up the lost 300 hp...

Prime mover: 200 lbs;

gen 588 lbs;

electric motor 2346

battery @ 1 hp/lb (your figure of 2.9 kw/kg) =300 lbs

Total: 3434 lbs (200+588+2346+300=3434 lbs)

My target empty weight for my "sport plane" roadable seaplane is 800-900 lbs with a peak power of 400 hp (critical for VTOL when the FAA ain't looking) and cruise power of 100 hp (must keep the top speed below 138 mph at sea-level full power cruise) ...

I can't get there also with Eaton style hydraulics either.

Current Eaton style hydraulics:

100 hp engine (Hirth F-30) : 120 lbs

400 hp hydraulic motors @ 1.35 hp/lbs is 540 lbs

300 hp acumulator @ 6.8 hp/lb 44 lbs

Fluid? 100 lbs

Total: 804 lbs (120+540+44+100=704), or about 18% the weight of an electric system.

I need that to be around 1/2 or about 300-400 lbs. Houston, we have a problem...

Oh, and I want to run it on CNG...among other fuels (liquid) so that I can get a 2500 mile range to do the south Pacific.

Oh, and it needs to have secondary power for the road...and a small prop for the water so that I can get around in National Parks without using the main air prop after I land in the water where it is legal to do so, but not legal to land on the road...

Clearly, one has to think out of the box to get where I want to go. I have 20 years to get there...

Thanks for the input.

Seaplaneguy

What would a 400 hp electric motor weigh? Artemis says 0.1704 hp/lb. What is your figure?

I 400 hp motor could be 160-180 lbs, if built along the lines of the Tesla's 200 hp motor. Such a motor would put out perhaps as much as 1/2 of that on a continuous basis, given good cooling.

If your prime mover is driving a generator, then another of the the same motor would generate 100 hp (75kW) continuously. (Depending upon how you were planning to operate this plane, a single motor would serve as both the motor and generator.) Your prime mover would need to have enough additional power beyond cruise power to enable you to charge up the batteries (unless you plan to run the engine fast on the ground for a while in prep for a takeoff.)

A 300 lb battery would be about 19kWh, so that would provide 300 hp (223 kW) for about 5 minutes -- enough for a takeoff and climb to maybe 7500 feet. If you do most of the climb adequately on 100 hp, then 50 lb (or maybe 100 -- I'd have to check) of extra-high-power batteries would get you into the air. So, about 230 lbs beyond the gas engine plane might give you the power for VTOL.

You'd be hauling around a lot of weight all the time just for the sake of takeoff. But VTOL would be very nice to have in a seaplane.

If I were made of money, (and also had abundant time for flying around in circles*) I'd buy one of the electric self-launching sailplanes.

* although it doesn't really have to be literally in circles: and old acquaintance flew from state college PA to just north of Atlanta GA and back all on one Jeep launch.

Ken,

From what you have been telling me, Artemis has "missed" the data for motor power density by 6.5-13 times??

The link I gave you quoted <0.5 kw/kg which translates to .17 hp/lb.

A good airplane engine is 0.5 hp/lb at 2700 rpm without a gearbox. You are saying 2.22 hp/lb short duration and 1.11 for continuous? That is 13 times short power and 6.5 times continuous more than what Artemis claims. Something is way way off here.

A big block dragster V-8 can get 8000 hp for a "short" time and weigh 1000 lbs (guessing), but I would not quote you such a figure. Is that what is going on here? That still has the around 4:1 ratio in favor of IC, just pushed to the extreme.

Question: What would such an amazing electric motor cost to build?

From what I have read, IC engine are 3-5 times lighter than electric motors. Take an IC at .5 hp/lb and the Artemis rate at .17, you get 2.94, or basically 3:1. The aircraft engine does not need a gearbox, but the electric does (?), so that ratio goes up from there.

Question: What kind of hp can an electric motor deliver at 2500 rpm without a gear box? Maybe that will get me closer to a fair comparison.

If what you are saying is close, then the end game of electrics vs hydraulics will be very close indeed, and it will come down to manufacture costs, which means the technology in production wins...politics... Unless of course, the cost of electrics never can compete with hydraulics because of rare metal requirements and such, which is what I suspect will happen when both are researched and advanced equally.

My boost of power for VTOL is for only <30 seconds of power, not five minutes. If you go from 100 hp to 400 hp you get around 4000 ft/min depending on many factors, or about a 2000 ft jump in 30 seconds, or enough to get you out of a bad situation (pilots will figure out the amazing ways to kill themselves...) and do VTOL. The problem as I see it is the 300 hp electric motor, and not the battery, and also, lest I forget, the prime mover has no synergy....

the main reason for the diesel electric powered trains is for

The petty cash awarded to those whom adopted it over the more efficient use of steam.

Seaplane and Ken:

Thanks for your replies. I have had some conversation with Ken in regards to this issue before. It was a long and interesting thread.

I believe a hybrid system designed around a constant output heat engine would require an energy storage device capable of incapacitating about 2 to 4 times the energy equivalent of its kinetic energy as maximum sustained velocity depending on grade ability. That is for a very high performance process. If it is simply peak efficiency that is desired; then the storage device would only have to store an energy equivalent of just over one acceleration to maximum sustained speed; but it would be a dog on a long hill. Either way; thats a small percentage of energy required for the plug in hybrids; and that has a very significant impact on the mass fraction dedicated to storage.

By integrating a properly designed prime mover control algorithm to control the relatively small variations in prime mover output, the process could reserve significant energy for peak power applications as well as continually maintaining storage capacity for regenerated energy.

The coming storage devices will in themselves be "hybrid" devices that combine capacitors in parallel with the chemical battery. Capacitors have very high power density but very low energy density. By hybridising chemical storage and capacitive storage you get the best characteristics of both devices. Get your drawing pencil out and use the symbols for a diode, a capacitor, and a battery cell. You'll get the picture.

I think you will find the hydraulic hybrid paper quite interesting in how two accumulators are used. There is no reason why those principles couldn't be used in ANY temporary storage scheme.

Again; it is possible to design a very high performance process where the prime mover power is sized only large enough to maintain maximum sustained speed plus parasitic power (air cond, power steering, ect).

Does anyone know the approximate value for the moment of inertia of a passenger car tire? How a about a railroad car wheel set?

Thanks

Gavilan.

Does anyone know the approximate value for the moment of inertia of a passenger car tire? How a about a railroad car wheel set?

I'd guess about 15 lb ft2 for a car wheel and tire. For a railroad car... maybe 500 lb ft2?

The coming storage devices will in themselves be "hybrid" devices that combine capacitors in parallel with the chemical battery.

Some prototype hybrid cars and some production heavy equipment use supercapacitors, but such capacitors share a drawback with LithiumX batteries -- high cost. Although supercapacitors may end up broadly used, I would not be surprised if high charge rate batteries make their use obsolete, at least in plug-in hybrids and EVs where the battery pack is relatively large. In small pack hybrids, like a Prius, capacitors may see more usage.

diesel-electric would be an excellent transition towards full electric application in vehicles, and I feel best candidate for this idea is... the good ole workhorse... trucks.

as some of the members have noted, the most efficient way to suck the max. energy out of a diesel motor is to let it run at optimum operating condition, i.e.: rpm/load. or not at all.

next the motors...... this is 2008 and we do have duty proven motors out there which are perfect for the job,i.e.: high speed brushless dc motors, e.g.: aveox, lehner and many others.

battery, Lipo/Lion..... I know it costs a bit, but that's temporary.

so let's see, we have a flat bed with 400-500 horses on tap...how?

6 sub-100hp engines slung below the flatbed on both sides of the truck/trailer.

2 150-kw motors coupled to the diff. vis single reduction gearbox.

since such motors could spin beyond 100,000 rpm, you'd have all the torque you need for starting off, and the main variable between get go and cruising is motor amp and supply voltage, which the ESC(electronic speed controller) is very capable of doing.

multiple engines provides for redundancy and on light load crusing, even 1 engine might do the job.

the lipo/lion battery could provide the boost and act as buffer during engine shutdown/startup.