Energy used for POWER!!!

Sorry not that skilled enough. I pass.

Me Too I reckon a big V8 Lovely noise

A 429, 426 or 427 @ about 500 hp should do. Pre 74 so you can hear the exhaust pulses.

Damn I feel the need for speed.

Brad

The problem looks like school work. So it's something you'd be better off doing yourself. Good use of flattery though. ffej

I have worked on that same problem! You are trying to motorize a vehicle with electric motor! right?

There is alot more to that problem than you may think! The info you gave is not a set actual or meaning that at any given moment "gravity" will take effect you know up or down a hill for example! ""remember the ground might appear flat however it is not! In your problem you may have goten that info from a spacific 'vehicle' and each is different as you know!

Now what you are looking for is"= Not Watts' Look more into the amount of amperes it take to produce a set movement / then load effects on the alike / then physical size!!!!!

K that will run you into a slump as did I! However, I starting looking into gear ratios in order to change the size!

and torque conversion to add and make more power to the drive than what the actual is being produced!

I have began building a proto-type to these effects, but it is slow for the parts needed are not all for sale! I have been making parts for it! Slow very slow!

Ok, now a 19" wheel takes so much torque to turn, right? Ok now you add weight, ok takes more torque but in the end you end up back to the beginning where it all starts!

freefeeling

Dear freefeeling. You are indeed right,I'm trying to power a vehicle using electrical motors. But I'm just a high school graduate and have been out of school for 4 years,I've been working and ,allthough school-level mathematics and physics don't provide you with the knowledge to do a mathematical problem of this magnitude, I'm planning to study mechanical engineering in the coming year.I'm glad to see so much intellectual intrest in my question and also would like to add that you sound like a inventor or a engineer. You picked up on my reason for this problem with amazing ease,I do however think your clouding the issue. I'm no genius but ,to my understanding, all research is done,making room for the unknown and working under perfect conditions. Therefore I have included in my problem added mass and no variation of surface gradient.It might also surprise you to know that I'm actually not english,but afrikaans and since the greater part of the internet is in english I do sometimes struggle with the info I'm stumbling apon. My current opinion is this,in order for the vehicle in question to be propelled at said velocity and acceleration,working under perfect conditions like a flat piece of saltflates with no wind on a nice warm day.This to me sounds like the perfect outdoor environment to do such tests,thus eliminating all those horrible problems of aerodinamic forces of wind and gravity.Airpressure should also be normal or average for this test.In such an environment my info should be sufficient as we are working with mostly Newton's laws.I believe that if one could calculate the force on the car at that point in time(250km/h),where to my understanding it should be at its max concidering the aerodinamic forces increase with the added speed aswell as the downforce adding additional weight,I also feel the amount of friction between the wheels and the ground would make a conciderable difference,but I have include a fair amount of weight to compensate for such problems.In actual fact the vehicle is considerably lighter. If one could calculate the force needed for this motion,one could determine the amount of power(torque and Kilowatt) needed for the motion and thus start to calculate the actual components of your drive system. Since I now posess less than matric maths you can understand that this problem is way over my head. Please if you could send me you calculations or just the formula's needed I would be of great help. Best of luck with your project though,go search for a invention called TheWheel.It might interest you,to bad its been patented.

You should ask the teacher what the rolling friction coefficient is for the tires involved. Then you'd have all the info you need. Remember that the aero drag will increase with the square of speed, but that the rolling friction is nearly constant.

Good Morning Puppylov

As stated above there are alot of little factors which can affect your final number, but to get you in the right ballpark I would reccomend you visit this site:

http://bgsoflex.com/auto.html

There are automotive calculators there which can tell you roughly what you'll need in HP, which you can then convert to watts. Just playing around, I noticed you'll lose about 30 HP due to aerodynamics and rolling losses, so make sure whatever HP you figure out to accelerate the car you add 30 to it. Also as a general rule of thumb, an automatic transmission accounts for about 20% drivetrain loss between the engine and the wheels. That is, if you had a 100 HP engine, only 80 of it will get to the wheels. A manual transmission is about 15%, so factor that in too when trying to calculate how much power you'll need at your motor.

Just what are you trying to get moving anyway? 2200 Kg (4850 lbs!) is HUGE! To put that in perspective for everyone else, the 2008 Hummer H3x only has a curb weight of 4700 Lbs (2132 Kg). The H3 has a 242 HP engine which moves it from 0-60 MPH (96.5 Km/h) in 8 seconds, and you want to accelerate in half that time with more weight! Thats 180 KW of power right there not accounting for losses. I would guess, based on this, that you would need something on the order of 500 Kw (again, depending on gearing and other factors) or 670 HP at the engine. That might seem a little high (and it should be given the weight!) but I think when you consider all factors, it may become more conservative then you realize. Consider this: The Tesla Roadster, considered probably the fastest electric vehicle out there, will do 0-100 Km/h in around 4 seconds with a 185 Kw (peak) electric motor but it only weighs 1220 kg! And, its streamlined (and gorgeous, untill you see the price tag) as you would expect in a roadster, so theres less losses there.

http://www.teslamotors.com/performance/tech_specs.php

If I havent driven this home enough, let me provide another example. I have a 1972 El Camino SS, with a built 500 HP 406 cubic inch engine, coupled to a TH-400 automatic, 3.73 rear end gears and 18" rims. It weighs 3210 Lbs, so figure 3400 Lbs adding my weight and accessories. Theroetically it should do 0-60 in 3.7 seconds, but the reality is it probably doesnt even come close (partially cause I can't get the tires to stick, heh heh heh).

A Porsche Carrera 4 (1405 Kg, 316 HP) has a 0-100 Km/h of about 4.9 seconds.

Another thing I wonder if you've considered is if that weight you gave includes the weight of the electric motor and its batteries. A large output electric motor is going to weigh considerably more then a regular v-8 of the same output power. And its going to take up alot more space. Couple that with the upgrades you'll need in suspension and things are starting to get costly. Very costly. Any affordable batteries may in total weigh more then the motor as well. And then what? Are you going to recharge this by plugging it into the wall? It would be cheaper to buy gas!

I guess my overall point is, you dont need fancy math and physics to get a reasonably close idea of how much power you'll need. Yeah, I have a degree in Physics, but the truth is no matter how much mathematical modeling I could do, theres so much in the real world that it just makes it tough to pin down an exact number, so its better to ballpark it anyway (Hell, even Einstien used "fudge factors"). And doing anything in a car that heavy is going to be very very difficult, but I wish you the best of luck.

Hi Pupptlov:

Sorry for jumping to the conclusion that you were a student.

I'll second most of what our guest has said here, with a couple exceptions. Electric motors can be lighter than their ICE equivalent. The 160 hp motors on the PML Flightlink demo Mini are about 28 lb each, if I recall. 640 hp total, about 120 lbs.

Batteries, however, are extremely heavy, unless you are willing to pay thousands for Li Ion -- and even then they are not light -- thus the 200 mile range of the Tesla, which is superb in elec vehicle terms, but considerably less than a gasoline fueled vehicle.

In electric vehicles, adding batteries adds weight, meaning that the motors must work harder, drawing more battery power. Thus, you will find almost that all typical lead acid vehicles get about 60 - 70 miles per charge, and LiIon gets about twice that. It doesn't matter if the vehicle is large or small -- it all scales pretty well. If you work hard on efficiency, you can get better numbers -- like those for the Tesla.

BTW, the problem you posed lends itself to calculus, but can be closely approximated by looking at the problem in one second increments. (Do this in a spread sheet, because that makes it easy to do the same calculation over and over.) AT first you'll have no aero drag, because the speed is 0. At one second you'll have some, depending upon how fast you are going. So for the next increment, you'll need to subtract that aero drag from the tractive force available, and recalculate, etc. etc. Meanwhile, the rolling friction is staying pretty constant, so you be subtracting it from the tractive force in each step too.

Even if you had calculus available, I'd recommend this stepwise approach, because it allows you to easily see what's going on at the end of each second (or smaller increment, if you want it be more accurate). But take a look at the links our guest has provided. Also search for "hyperphysics" for a site that gives you all the physics background you'll need. Good luck. You can probably do this with the math you know, but you'll need to brush up, and you'll need to become more familiar with physics. Have fun.

Dear guest Thanks for all the info.The specs of the tesla looks impresive,I see it uses a 3phase,4-pole,single rotar motor.My understanding is that the poles refer to the eloctromagnets on the rotarshaft.(forgive me if I'm wrong).What would the theoretical effect be if one were to change it to 8 electromagnets half that size?Or swap the permanent magnets,on the housing,with the electromagnets on the rotar(I presume the number of magnets and electromagnets would just swap,but the fluctuations in electromagneticfield could increase by alot),would this increase the effectiveness and/or performance of the motor?If one were to make a housing,equal in size to 2 of above mentioned housings,containing 2 chambers each with a identical rotar both running on one shaft,What could one expect from such a motor?I see the Tesla requires 3.5hours of charging time,what amount of electricity useage does t at amount to?You El Camino SS sounds like a beast,maybe try a different gearbox suspention combination,don't know if it would help much.Pulling away,foot on the floor with it must be better than sex,luck for me girl I don't own it,lol.The vehicle I used for my data makes use of a 4.999cc V10 engin and weighs about 1790kg unloaded,the 2200kg is its weight with max load.I used this figure to give me a ceiling of data under which I could structure the rest.I did this because I would like to improve that cars performance but also its economy.( Adventurous I know,but one can dream)=).The webcalculators you provided is rather accurate,it showed this vehicle at 516 HP/385kW at peak power at 7750rpm and its specs soos it at 373kW,accurate enough for my purpose.I've however found an interesting site with calculators for 3phase motor,using this with 400V at 2A it gave me an impresive 1385.64kW,with an efficiency of 30% it gives me 415.69kW and at 1500rpm 2646.23N.m of torque at the shaft.Al the input data I used is purely random from info I could remember seeing,the input data sounds realistic and the results are quite impresive.Don't know about their accuracy though, found it on http://www.wentec.com/unipower/calculator/3phase.asp I can't wait for your reply or that of anyone else for that matter.

To answer your question, a 2200kg car at 250 km/h, .32 cd, and a Frontal Area of 2.15 m^2 would need about 250 hp or 190 kw. It would have a 46 mpg economy at 55 mph, and 8.2 mpg at 155 mph (250 ks) if you plugged it in to the grid, based on 27% efficiency at the motor (30% grid, 10% charge loss). Frankly that is not very good, or at least not something to write home about. As for the acceleration, the gearing, shifting time, etc., would have to be considered in a simulation. Go to the link below to get a good comparison of current cars. My guess is you would need about 300-350 hp.

Try this link: auto analyses

Put the equations in a spreadsheet (like Excel) just like the link has. You can then change weight, Cd, Rolling Cd, etc as you like.

As for an electric motor being lighter, such is NOT true. An air motor can be up up to 1/5th the weight of an electric motor per hp/kw. You just have to supply it with compressed air, just like you have to supply an electric motor with compressed (volts) electrons (CFM). There are real physical reasons electric vehicles have not been successful. One can make an ICE engine that would be much more (2 times) efficient than an electric-grid (30%) electricity supplied electric car. Try to understand WHY such cars as the Teslamotors can get good mileage and WHY an ICE engine currently does not.

By using the above link and doing the spreadsheet you will clearly see that there is a lot of improvement. As former CIA director Casey (Clinton admin.) said on C-span several months ago, top engineers think that a 525 Mile/gallon 4 place passenger car is possible that a person would want to own and drive. Such a car would weigh about 500 lbs and be 65% efficient at 30 mph (average city speed). When a car becomes very lightweight, then you must address crash weight ratios, and keeping it on the road. The entire way the car is made, crash structural strategies, etc will need to change. That said, when one looks at it in detail, one moves to the air, as in seaplane...to get the real good economy and safety needed by customers. A good airplane can be around 1/2-1/3 the drag of a car of equal cargo, and no rolling friction....

As for an electric motor being lighter, such is NOT true.

The Tesla's motor is 189kw (253hp) and is just under 70 lb. A comparable ICE would be 400lb.

The PML Flightlink motors are 25kg for 120 kw (160hp), not the 28 lb I wrote above. But 25 kg is still far lighter than a 160 hp gasoline engine.

Even the little motors in my trike are 15hp and weigh 22 lb. The 10 hp gas engine in my garage is 68 lb.

I call BS!. Almost every ferrari V-12 is under 400 lbs (most closer to 300) and they put out a heck of alot more then 253 HP. So are lamborghini v-12's, mazda rotary engines, mercury marine (275 HP 350 lbs 2 stroke!), the pontiac super duty 4 cyl makes 300 HP at 350 lbs, if you want to get fancy the pratt and whitney ST6B-62 weighs 260 Lbs and puts out 550 HP. GM's LS-7 for the corvette weighs in at 458 Lbs, but is rated for 505 Hp natually aspirated, from the factory. Most major manufactuer v-8s weigh in at around 500-600 lbs, but 1000 HP supercharged small block v-8s are so common in hot rodding nobody blinks when they see one. Its not unheard of to even see 2000 HP big blocks.Let us not forget that the tesla is a specially designed not readily available motor. Just doing a cursory internet search, I see readily available 3 phase AC high efficiency motors rated for 500 HP weighing in at 2147 Lbs! http://www.emservicenter.com/inventory/details.cfm?item=1189798730

You simply cannot beat the potential power to weight ratio of a well built IC engine over an electric. Even better would be a turbine engine.

You seem to be reinforcing my point: virtually all the engines you mention are at the high performance, light (in hp/lb) end of the spectrum. My Honda Accord engine is 350 lbs and produces 160 hp, and it's pretty typical, at about 2 lb per hp. But even using your examples, most at 1 hp/lb, the PML Flightlink motors (which include built in controllers) are 55 lb and 160 hp, for just short of 3 hp/lb. The ratio for the Tesla motor is a little better at 3.6hp/lb.

Of course, electric motors for stationary industrial use are very heavy, because lightness in not a virtue (just as in fork lift trucks the heavy batteries are a benefit, not a drawback). A similar condition exists with industrial diesels: here's one that is 693 lb, and 6 hp, for less than .01hp/lb. which makes your industrial 500 hp electric motor look like a featherweight by comparison, with about 25 times the output per pound.

But for a more realistic comparison we need look no further that the Tesla. The Lotus's original engine is 300lb and 190 hp (.63 hp/lb). The Tesla replacement is 70 lbs and 253 hp (3.6hp/lb). Same car in both cases, so it is hard to find a more apples-to-apples comparison.

You seem to be missing mine, and that is what is more readily available. You can walk into any junkyard and get a domestic V8 suitable for building well in excess of 2HP/lb, but tell me where a kid is going to go get a tesla motor, or better yet the batteries? If you're dilligent you can even occasionally find super high performance engines in junkyards and racing salvage specialty yards (theres a porsche in the junkyard down the road from me I've been eyeing for sometime). The best this kid is going to be able to find and afford is going to be a heavy, off the shelf electric motor, and probably conventional 12 volt lead/acid marine batteries without spending a years pay. Lets us not forget that teslas arent EVEN ON THE ROAD yet and the company is still taking pre-orders.

Dear all. I greatly appreciate all your responses,you seem to enjoy debating the topic.Let 'This kid'=) explain something.I'm just busy with a personal project,this is still in the design phase and will not be constructed for many years(hopefully not to long).My project does not aim to produce a conventional vehicle,but my ideas are in need of knowledge I'm not yet familiar with.I'm currently designing a 'new'(hopefully,buti ts still all theoretical according to what I know) electric motor which I feel might be powering the vehicles of years to come,or at least give some of you intellectuals an idea.If you haven't allready thrown it out as impossible.If anyone knows someone who would be willing to look at my idea and tell me what they think I would be grateful.I also don't want my idea(if by chance unique) to be stolen,but even then I would have accomplished more than at present.Everyone seems to make very understandable comments,but we are in a era were we are forced to look at possibilities for new technologies to better the world of tomorrow and I'm sad to say,the beautiful V8 is not part of such a future.I aim to make it and museum item.Were people can gaze and marvel it beauty and power,but laugh at its shortcommings.Would I be able to use the original info of my donor vehicle as a benchmark for my project or not?

Would I be able to use the original info of my donor vehicle as a benchmark for my project or not?

The Tesla proves that an electric vehicle can be very high performance, and shows that on an apples-to-apples basis electric motors are much lighter that their ICE equivalents. 200 mile range is pretty impressive, and suggests that before too long, we could be up to 350 mile range. Ten minute recharges are possible now (not with the Tesla's batteries but the the Phoenix's), although such charging stations are effectively non-existent. But the infrastructure exists right now to put the stations into place: every Starbucks could have 480V power, and 5 or 6 charging stations.

We have two cars, one of which we use around town, and which never goes over 200 miles in a day (typically 20-30). So for us, it would be a simple matter to use an electric car, which should be cheaper to buy than an ICE car, given reasonable production volume. Running costs would be a fraction of those for an ICE car.

So, I think you are right, ICEs might be museum pieces before too long. (Of course, Ferdinand Porsche might have though that 100 years ago.)

Mr. Fry,

I did NOT say an ICE. I said and AIR MOTOR (like a shop grinder or dentist drill motor).

Like I said, give me free compressed air (electricity) to drive my air motor and my air motor will outperform your electric motor any day on a power/weight basis.

Having an ICE driving a compressor that flows air to an air motor, would of course, make little sense and the losses would be very high compared to an electrical system (read hybrid electric car) due to the nature of thermodynamics. An air hybrid in theory (lots of researchers, including myself, are working on this) could enhance the thermodynamics, where an electric hybrid could not) and ultimately be MORE efficient than any electrical based system, and have brake recovery, solar recovery, and low grade/ multigrade fuel ability. One needs to respect the physics demanded by the energy domain of the process and design to enhance the advantages (air/electric).

Currently, we have chemical energy input and combustion as the release means via air/heat motors, that then turn generators to create electricity. Fuel cells were/are thought to be great, but they too have strong thermodynamic issues and in reality will be much LESS efficient than an air hybrid long term, in my opinion. There is zero or no news on air hybrids, and this is where I believe success will follow, installed, of course, not in a car, but a roadable (sea)plane. Bag the boat, buy a seaplane. Way more fun in the sun...

Yor concept sounds interesting,but what about airtrafic control,fuel,licenses and the prosess untill ur allowed to fly, if everyone should own a airplane?Think of drunk flying home from a bar,and how to handle the parkingspace issue?To my knowledge a small plane occupy much more space than a small car,underground or underroof parking would also have to chande dramatically if planes were to be parked there.Sounds like something out of Starwars,maybe you should start on the interesting topic of antigravity and try to figure that out to use for propulsion in your planes.It would dramatically change their design.Thanks for the info.

Just out of pure intrest I would like to divert your attention to a patented invention simply called 'TheWheel'.Go search for it,you'll be quiet impressed.I would think a similar idea could be a devastating success. =-)

PML Flightlink makes a wheel motor that appears a little more efficient than TheWheel. TheWheel advertises about 85% efficiency (motor and electronics) whereas PML is advertising over 90% combined, if I recall. The PML motors are much lighter (according to the specs), but even they are heavy when compared to the spindle and CV joint that normally resides in the space taken up by a wheel motor. PML promotes the idea of having no friction brakes at all, but I don't know that people will be comfortable with that. But even then, the total wheel weight is too high for my tastes, although if the units were on an medium sized truck (where you might actually need the combined 640 hp) then the weight is acceptable. For good ride and handling, unsprung weight (all the weight that moves with the wheel over bumps) needs to be kept low as a percentage of total vehicle weight.

The first hybrid car used wheel motors, and the overall system efficiency was about 85%, I've read. This was back in 1903.

A challenge in wheel motors relates to the fact that copper, permanent magnets, and coil core materials are heavy. Lighter wire (aluminum for example) doesn't conduct well. But if the motor were better integrated into the wheel, so that the tire rim is really the rotor, I think there'd be hope for getting the weight down. Until that happens, then mounting the motor (which would be wheel motor style: very high torque low rpm) inboard seems to make sense from a ride and handling standpoint.

But nevertheless, the idea of a wheel motor is really appealing, and if I could find three that were reasonably priced and light, I'd use them on my trike.