Author Topic: Treadmill Dyno  (Read 164114 times)

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Madscientist267

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Re: Treadmill Dyno
« Reply #33 on: February 23, 2011, 10:36:51 PM »
Quote from: Ghurd
I keep coming back to something from the other post

I do too, but I think there may be differences as to why. Mine is, cooling the seat is the one part of the car that I would have never bothered with. Unless we're talking extended runs here, which does not appear to be the case. Correct me if I'm wrong.

And even with extended runs (take NASCAR for example), they run for a few hours without anything like that (to my knowledge).

So why do it for this? Seems like the added weight of the water and associated electronics/components needed to cool the seat will offset your weight factor a fair amount...

Steve
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taylorp035

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Re: Treadmill Dyno
« Reply #34 on: February 23, 2011, 10:51:09 PM »
Quote
I'd be willing to bet that regardless, the shortest, twiggiest guy on the team ultimately ends up becoming the driver.

While I'm on the subject, how much does driver skill play into this? Like percentage wise? Or is that a well known 'constant'?

The minimum driver weight is 130 lbs.

As for percentage for mpg, I would say up to 20% for a sane person.  Previous people with our same car have gotten 400 mpg, but they were driving at 30 mph average, or even as high as 50 mph.
This year's car will be easier to control the speed, so I would say closer to 5%.


Quote
Wondering, since it is almost an antique engine, are the antique efficiency boosters done?
(port & polish the head, intake, and exhaust, plus make sure the gaskets are not goofing up the works)

Yes sir, all ported and polished.  Last year's engine was 100% stock, so we may have a big gain right there.


Quote
I do too, but I think there may be differences as to why. Mine is, cooling the seat is the one part of the car that I would have never bothered with. Unless we're talking extended runs here, which does not appear to be the case. Correct me if I'm wrong.

And even with extended runs (take NASCAR for example), they run for a few hours without anything like that (to my knowledge).

So why do it for this? Seems like the added weight of the water and associated electronics/components needed to cool the seat will offset your weight factor a fair amount...

You would be wrong about the nascar cooled thing.  They have cold packs and various other things to keep the driver cool in the 140 degree F car.  Our car is kinda of the same.  I like to call it the easy bake over since it gets so hot.    We did have an electric ducted fan in the nose of the car (from a model rc jet), which could produce ~50 mph winds inside of the car.  Unfortunately, we had a significant crash while testing over Christmas, and it was destroyed.  The run takes a minimum of 38 minutes to complete + fueling time, so you could be in the closed car for 50 minutes on tarmac on a 90 degree day.

As for the weight of the cooled seat, we are making the whole thing removable.  The system may weigh 5-10 lbs, so we may remove it after we get some good runs in when we want to squeeze those last few mpg's out of the car.  Last year's numbers were, in order: 650, 678, 69x, 776.59, 630, DNF.  The 630 mpg was because I tried doing only 3 burns to get around the track, which meant my speeds went from 30-4 mph.  The 776.59 came after we pumped the tires to 55 psi, emptied every last item out of the car, and removed the air filter.  Also, the driver was the lightest of our 3 drivers, at exactly 130lbs with the helmet on...  and she drove the car at a slower speed (24-10 mph).  According to my excel mpg calculator, we should of been able to get ~ 850 mpg if it was driven slower.



« Last Edit: February 23, 2011, 11:00:25 PM by taylorp035 »

SparWeb

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Re: Treadmill Dyno
« Reply #35 on: February 24, 2011, 02:03:46 AM »
Have you heard of, or already considered a NACA duct?  It could introduce a flow of air into the cabin with the least disturbance to the external flow of air around the car.  Unfortunately that would make the cooling speed-dependent, but if the bulk of the heat is coming from the engine and motors, then the sources of heat are speed-dependent too.

A reflective coating on the windshield would cut down on solar heating.

...and you're going to paint the car white, right?  :P



You would be wrong about the nascar cooled thing.  They have cold packs and various other things to keep the driver cool in the 140 degree F car.  Our car is kinda of the same.  I like to call it the easy bake over since it gets so hot.    We did have an electric ducted fan in the nose of the car (from a model rc jet), which could produce ~50 mph winds inside of the car.  Unfortunately, we had a significant crash while testing over Christmas, and it was destroyed.  The run takes a minimum of 38 minutes to complete + fueling time, so you could be in the closed car for 50 minutes on tarmac on a 90 degree day.

As for the weight of the cooled seat, we are making the whole thing removable.  The system may weigh 5-10 lbs, so we may remove it after we get some good runs in when we want to squeeze those last few mpg's out of the car.  Last year's numbers were, in order: 650, 678, 69x, 776.59, 630, DNF.  The 630 mpg was because I tried doing only 3 burns to get around the track, which meant my speeds went from 30-4 mph.  The 776.59 came after we pumped the tires to 55 psi, emptied every last item out of the car, and removed the air filter.  Also, the driver was the lightest of our 3 drivers, at exactly 130lbs with the helmet on...  and she drove the car at a slower speed (24-10 mph).  According to my excel mpg calculator, we should of been able to get ~ 850 mpg if it was driven slower.
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taylorp035

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Re: Treadmill Dyno
« Reply #36 on: February 24, 2011, 02:25:07 PM »
Quote
Have you heard of, or already considered a NACA duct?  It could introduce a flow of air into the cabin with the least disturbance to the external flow of air around the car.  Unfortunately that would make the cooling speed-dependent, but if the bulk of the heat is coming from the engine and motors, then the sources of heat are speed-dependent too.

A reflective coating on the windshield would cut down on solar heating.

...and you're going to paint the car white, right?  Tongue


Yes, we plan on having a base coat of white.  If the carbon fiber gets too hot, the glue will get soft and bad things start to happen.
I have not heard of a NACA duct, but maybe my team member who is into F1 may know about it.
As for the source of the heat, most of it will be from the sun and the driver.  The engine barely gets warm.  Most likely, we will run the car a bunch before we go drive around the track so everything is more efficient.

 

SparWeb

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Re: Treadmill Dyno
« Reply #37 on: February 24, 2011, 03:18:57 PM »
Funny coincidence, there is a NACA duct on that e-trike photo that just got posted on your other thread!

Google "NACA Duct" and you'll get lots of pictures, plus a bunch of mis-uses and confusing info.  Best to go to the source.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090012113_2009011314.pdf

(12 MB download)

Yeah yeah yeah, your grandparents were old when it was published, I know.  But let that give you some idea of how good an idea it is, since it's still around.


As for carbon fibre and heat - common problem.  You can actually get temperature-sensitive stickers, that change colour at a specific temperature.  These are used in composite aircraft and the pilot is supposed to check them before flight.
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taylorp035

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Re: Treadmill Dyno
« Reply #38 on: February 24, 2011, 04:37:50 PM »
If we bring a lot of air in, the air must go out of the wheel skirts, while may cause more of a disturbance than it is worth.  But thanks for it anyways, it is definitely a possibility.

taylorp035

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Re: Treadmill Dyno
« Reply #39 on: February 24, 2011, 09:24:42 PM »
Today we got 23 items that we had ordered.  This included out v-belt and our two pulleys, so we can now hook up the engine to the treadmill motor tomorrow night and it should run a lot smoother than chain.  We also got the 10 light bulb bases, but the light bulbs or ammeter have not arrived yet.

We also ordered some low rolling resistance tires.  Unfortunately, Michelin is not making any of the good tires this year, so we bought some Schwalbe tires ($300 worth, for 6 tires, 2 different brands).


I should give an update sometime Satuday I would think of the progress.

Madscientist267

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Re: Treadmill Dyno
« Reply #40 on: February 24, 2011, 10:10:46 PM »
Did some experimentation with this last tank of gas in my car... Still got some more to do to make it more 'valid' data (that whole multi-sampling thing). It's a 2011 Toyota Camry with ~6K miles on it, 'rated' 33MPG highway (which is where I do a fair chunk of my driving).

While I started out with a 1/4 tank of gas, I only really applied it all after the idiot light came on, I'm a mile watcher, comparing needle to trip odo regularly and religiously. So this has some merit, even though its really only a single 'event'. After the idiot light appears (~1/8 tank), its good for about 40 miles with my normal driving style before things get scary (bad side of E).

I had to run all over BFE today, and normally, I would have had to gas up LONG before I did, but I thought about a few things we were discussing, and applied what I could to see what would come of it.

1 - Keeping raw speed down. Kept it below 65, even in the 70 zones. Was running more like 60. If you were one of the people that flew past me glaring, kiss my #@%, at least I was in the right lane!  ;D

2 - Keeping engine RPM down. Went to as high of a gear as quickly as possible.

    A - From a dead stop, only very short acceleration hits on 1st and 2nd gear (fair throttle, but limiting to ~3K RPM).

    B - 3rd was a little more lax on the throttle, and shifted out at ~2500 RPM.

    C - 4th was never allowed more than the throttle being cracked open, and limited to 2000 RPM.

    D - 5th and 6th (except where I was forced to bring the speed up due to traffic conditions) were also kept cracked at most, and target RPM was always less than 2000. I started out trying my 'out-the-hat' 1200 RPM, but this is down just a touch too far on the torque curve to be practical. Car was also groaning. So I upped it little by little until I found the lowest RPM that didn't squawk. Turned out to be ~1400 RPM. Tried my best to stay in the 1400-1600 range for a majority of the 'test'.

3 - Drafting. While I was only presented the opportunity twice, but they were both for decent runs, and I slid in as good as I could get without freaking the truckers out. I guess it's dangerous, but it's also damn appealing! The closer you get, the better the savings. I hung out at about the 50 ft mark @ 60 MPH-ish which works out to something like 20% savings IIRC (according to mythbusters test...). I probably got in all of about 20 miles collectively under draft conditions.

4 - Pulse and Glide. While the pulse part was minimal, I did a lot of coasting anywhere there was a hill, to keep engine speed down that much further. Did this countless times during my adventure today.


My round trip was on the order of ~100 miles, and the idiot light came on about 25 miles in. By fairly repeatable math, I would have had to refuel just after leaving my furthest destination, ~65 mile mark. That's when the needle looks as scary as I'll ever let it.

The results of applying the above however are rather astounding, and even more so because they only were applied to the last 1/8 tank.

Since I track my mileage, I could easily look back at similar tank fills, and see the corresponding distance. Typical 'damn, thats scary' happens at about 450 miles. This works out to 17.6 gallons of fuel, rendering 25.5 MPG. Yeah, I have a tendency to 'get on it'... heh. I'm normally one of those 'get it up quick, and hold it 10 over' type guys.

This tank, I did finally have to stop, as it hit the bad side of E about 10 miles from home, and all said and done, 514.2 miles on this tank! Pump said 17.7 gallons. 29 MPG! ;)

Even after the fill, I continued the 'economic' style, and I have a very long trip ahead of me tomorrow, which I will continue to use it then as well. Don't think it will run me out of gas, but I'll have a good idea just by gazing at the needle to figure out about where it stands.

Till then,

Steve
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RP

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Re: Treadmill Dyno
« Reply #41 on: February 24, 2011, 10:32:17 PM »
I used to have a 93 Cadillac Deville with the mpg display and tried a lot of experimenting like this.  It was a 4 speed automatic but I found that by letting up on the pedal at the right speeds I could get it to upshift early to keep the rpms down.

Also I changed my route to favor stops at the top of a hill rather than at the bottom (if I had a choice) so that rather than converting all my kinetic energy to heat in the brakes, some of it was essentially stored as potential energy I could get back when starting off again.

As to drafting, I found there was a spot about 1.5 seconds behind a semi where my mpg jumped up by about 3-4.  This is a little closer than the 2 seconds recommended for safe driving but it felt safe to me.

By paying attention to all this stuff and trying to avoid using the brake pedal as much as possible I could raise my average mpg from about ~16 to about 23.

taylorp035

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Re: Treadmill Dyno
« Reply #42 on: February 24, 2011, 10:37:15 PM »
I have tried the same thing with my 99' olds 88.  I usually average 22-23 mpg, as low as 21 if you have a foot made of lead.  If put the cruise on at 55 mpg on the high way (half of my trips), and never break 40 on the rest of my journey, I can do 24 mpg at best.  Of course, idling for 10 min a day can lower mileage by 2 mpg easily.  With the snow tires on, I average 20 mpg +- 0.3 mpg.

The reason I think my car only does 1 mpg better when your are really nice to it is because the engine is less efficient at the lower hp levels.  If I do 4k rpm every where I go and then coast, I get about 20-22 mpg.

On the other hand, our 01 bmw 740 will go from 29 hwy to 20 hwy if you aren't nice to it, thanks to the v8 and 4450lbs dry weight.


taylorp035

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Re: Treadmill Dyno
« Reply #43 on: February 24, 2011, 11:26:09 PM »
The most noticeable drafting is when you drive our 97 Jeep grand cherokee behind a semi, maybe 30 feet, in which it feels like you are being sucked towards the truck. 

During the summer, my job is about 800 ft in elevation lower than my house, so I can pretty much coast for 11 miles.  Coming back, you have to give it a lot of gas, but I think it is more efficient.  I was able to get 23 mpg on 40 mph roads, which is pretty good.

As for hwy speeds, in the jeep, at 55 on a flat road, you get ~26 mpg.  When you hit 60, it goes down to 22 mpg and at 65, it goes down to 17-18 mpg.  Interestingly, you can get 29 mpg in 2nd, 3rd, or 4th gear going at a steady 25 mph.

I heard that if you take a manual jeep cherokee and do the burn and coast method, you can get 100 mpg.  I don't doubt it in the least.  Having an engine idle so much is such a waste of power.  Supermileage teams who run their engines at 10% throttle for the solid 9.6 miles only get ~ 200 mpg (this has been proven 100+ times).

Madscientist267

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Re: Treadmill Dyno
« Reply #44 on: February 24, 2011, 11:29:51 PM »
It's interesting to note however that an automatic transmission alone can suck 20% of an engines power right out of the 'system' on its way through the drive train. This will either translate to less power to the wheels, or less fuel mileage, depending on how you drive.

RP -

Gotta admit, though, 16 -> 23 is a pretty fair amount, particularly being in an automatic. Were you doing any true 'neutral coasting' at all? Not that I recommend it; they say it's hard on an auto to manually shift it (unless its one of these new 'manumatics')...


Taylor -

Strange conflict between the '99 Olds and RP's 93 Deville... They're both in what I call the 'boat' class, particularly the Deville. It's interesting that they're comparable when feathered, but share no ground when 'dogged'. And the Olds is the smaller (and presumably lighter) of the two!

Not sure of the specifics on engine size for either one however, which may play a role in efficiency (sometimes the larger engine IS more efficient). An underpowered engine has to work too hard (and therefore uses more fuel than it would otherwise need to). Same thing happens on the other side - an oversized engine uses more fuel just running, and if all the torque it CAN create is never utilized, the extra fuel usage goes to waste just keeping a stoich mixture. So there is a sweet spot in terms of engine size vs weight and drag...

Definitely a head scratcher and has me wondering a few things.

While I'm pondering over the unknown, I'll throw mine out there - The Camry is a 2.5 4 banger with the variable valve timing... FWIW.

Steve

PS - RP - Love the dog... hahaha that's funny right there, don't care who y'are that's funny! LOL

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zap

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Re: Treadmill Dyno
« Reply #45 on: February 24, 2011, 11:36:02 PM »
I broke down and bought a UltraGauge back in December... about the time work slowed down to... nada :'(  Because of that I don't have many miles on it yet but it's sure fun to watch the number jump around.

Madscientist267

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Re: Treadmill Dyno
« Reply #46 on: February 24, 2011, 11:39:34 PM »
I agree completely about the idling. Very wasteful.

My conflict there comes from lubrication concerns.

Toyota (and others now) gets away with it seemingly unscathed in the Prius. That thing cuts off in a heartbeat if it determines that the engine's output is not going to be necessary, and starts up just as readily when it is.

But I worry about what comes down to essentially continuously 'dry-starting' the engine. Most of the wear in an engine takes place during and immediately following cranking, following a settling period where the oil drips away from the parts. Before the oil has built up pressure and has otherwise been sloshed about to lube everything that needs it, there's metal on metal everywhere.

It's half the reason that Diesels last so long - they never shut the friggin things off. Of course using an 'oil' as a fuel doesn't hurt upper cylinder lubrication any either.

I'd like to believe that there's a pre-start electric oil pump that brings the pressure up to value at the very least for the continuous start/stop cycling those engines go through.

It's the one reason that even though my car is a stick, I don't kill the engine with the key during coasts. Too afraid of reduced engine life... ?

Steve
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taylorp035

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Re: Treadmill Dyno
« Reply #47 on: February 24, 2011, 11:45:19 PM »
Quote
Strange conflict between the '99 Olds and RP's 93 Deville... They're both in what I call the 'boat' class, particularly the Deville. It's interesting that they're comparable when feathered, but share no ground when 'dogged'. And the Olds is the smaller (and presumably lighter) of the two!

It's definitely a boat!  It's really light though, at ~3600 lbs empty.  It has the 3.8L series 2 v-6 engine at 205 hp and 230 ft*lbs.  It rolls really, really well and it is in good running order for a 12 year old car.
The bmw is exactly the same in the dimensions category, but it has 282 hp (probably more like 300), and 325 ft*lbs with the 4.4L v8.  It weighs in at 4450 lbs.  What's different with it is that it uses no gas when you let off the throttle, so it turns the engine over while you coast.  This affects the coasting, but it doesn't really matter.  But, you can keep it below 1500 rpm all day long. People with the v-12's can keep their rpm below 1200.  I remember going to the E.R. once and we hit 105 mph, but the tach didn't even hit 3k rpm  ;D  Nothing like a car meant for the autobahn...

With the whole family piled in on a trip, the bmw would weigh 5500 + lbs, but you could get 31 mpg at 65 mph.  At 55 mph, you can get 38 mpg.

Tomorrow I plan on doing some simple comparison tests between our efi engine and the stock engine.  I will try to keep all of the variables the same (up to running temp, same load, same belt tension...)  We have a 50 cc burret style thing that has a connection for a fuel line, so we should be accurate to 0.1 cc's of gas.  The load should be the same and kept accurate to with in 1% using the volt meter.


Edit:

Quote
It's the one reason that even though my car is a stick, I don't kill the engine with the key during coasts. Too afraid of reduced engine life... ?
Quote

I have turned my car off while coasting down big hills, for maybe 30 seconds at 40 mph.  The downside is you loose your power steering and power brakes, which are nice for those white tailed deer and dodging the monster potholes...

I sometime put it in neutral, but it doesn't seem like it does much, especially since my car idles at ~1000+ rpm.
« Last Edit: February 24, 2011, 11:55:09 PM by taylorp035 »

taylorp035

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Re: Treadmill Dyno
« Reply #48 on: February 25, 2011, 12:01:51 AM »
Here are the tires we bought today:

http://smtp.schwalbetires.com/bike_tires/road_tires/kojak

http://smtp.schwalbetires.com/bike_tires/road_tires/marathon_racer

We are running 20" x 1.75" rims.

The keys to low rolling resistance are:

radial tires (all bike tires are cross ply)
no tread
high pressure
wider tires


Our tires that we own that have a coefficient of 0.0008 are radials.  They are the only ones in the world and you can't buy them.  The next "best" tires have a coefficient of 0.0024 or 3 times higher because they are cross ply.

I can't wait til they make carbon fiber stranded radial tires with an inflation pressure of 200 psi.  Unfortunately, the tires can actually get too bouncy and cause major problems that cause the tires to "microslip" and cause more friction.  This is especially important when you don't have a suspension.

Madscientist267

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Re: Treadmill Dyno
« Reply #49 on: February 25, 2011, 12:05:54 AM »
Quote
With the whole family piled in on a trip, the bmw would weigh 5500 + lbs, but you could get 31 mpg at 65 mph.  At 55 mph, you can get 38 mpg.

I've noticed fully loaded long trips to be more efficient too... Never really could make heads or tails of it.

Figured it was just because it was completely highway driving that accounted for it, but I'm convinced the added weight plays a role, just not sure how exactly... ?

One of my theories is that the extra weight allows for more kinetic energy to be stored, and at highway speeds, this could be equating to less modulation of the throttle over the inevitably numerous subtle slopes that one encounters on the freeway (speaking in terms of mostly flat terrain).

Mountainous drives are a whole different animal, as you pointed out earlier, and can really throw the numbers if you're not paying close attention to how you're viewing the 'data'.

Quote
The downside is you loose your power steering and power brakes,

Ahh, yes. In the Camry however, the steering is electrically assisted, so as long as I return the ignition switch to the 'run' position, the power steering stays with me. The brakes are assisted electronically somehow as well, at least to some degree, but that's not clear exactly how. The brakes do feel different with the engine running than without, but in the 'accessory' position, the only 'power assist' you have is what you can deliver to your thighs from your arms with both feet on the pedal... LOL Maybe a vacuum pump (not even sure there's a vacuum booster in it though), or something that the ABS modulator does? Dunno... ???

You'd think someone like me would know the car inside and out already, but that part of me somehow lost interest some years back in knowing all the details of the machine as a whole. I think when carburettors died off, they took a piece of me with them.  :'(

Ahh, the good ol' days, when you didn't have to bend over the fender to work on your straight six... Just jump in the engine compartment and stand next to it!  8)

They are gone, however, for good, me thinks.  :-\

Steve

EDIT -

"wider tires" ... ? Seems counterintuitive...
« Last Edit: February 25, 2011, 12:10:41 AM by Madscientist267 »
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taylorp035

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Re: Treadmill Dyno
« Reply #50 on: February 25, 2011, 12:11:16 AM »
Well, I'll be back hopefully on Saturday night, if not by Sunday.  I'm always open to ideas!

Bruce S

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Re: Treadmill Dyno
« Reply #51 on: February 25, 2011, 11:32:30 AM »
Steve;
There is a relationship between the width of the tires and the amount of "micro-slip" or traction.
During winter months, I change my tires ( actually have 2 different sets already on rims) 185/75R14 32psi for winter, 205/70R14 35psi summer.
The narrower tire allows more of the weight of the vehicle to be put towards better traction.
A wider tire, to a point, allows the weight of the vehicle to be spread out.
There is a maximum here too where too wide gets you nothing more than more expense and more slippage due to more tire being on the road leading to less handling.
AND bounce, which is what I generally laugh at when the "hipsters" put those 20" tires on.

Hope that helps;
Bruce S
 
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taylorp035

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Re: Treadmill Dyno
« Reply #52 on: February 26, 2011, 12:13:06 PM »
I hadn't thought of the connection between car tires and bike tires like that before Bruce.


Well, I made it it Saturday ;D   Last nights progress was fairly large. Things that we accomplished included:

Wiring up the 3000W of light bulbs on to a nice board.
Adding the 3" v-belt pulleys and belt to the engine
Running the stock engine and getting a small amount of data, which will be presented below.
Sanding and finishing the last bits of the car.
Putting the cooled seat components together and testing them out.
Fixing the bore for the bearing in the rear clutch.
Took lots of pictures and video  :)

Now for some pictures:

The 1 set had 3 bulbs, the 2 sets had 6 bulbs, and the 3sets had 10 bulbs, all wired in parallel.
The voltages are at full throttle and so were the amperage values.  The 3rd amps value was calculated, since our meter was only rated for 10 amps.
The watts was then calculated.  The ohms value was also calculated, so to see if there was any consistency.  It was about 50 ohms per bulb.  The bulbs are 300w.


Here is the load.  There are two switches on the bottom to turn on the last two rows.
It was obvious that the treadmill motor could put more of a load on the engine than was required with all 10 bulbs on.
For a reference, no load voltage at full throttle was about 105v.  The treadmill motor is about 33 rpm / v, but that number may dip a little under load ????


We had to lift the light bulbs off the table, since it was vibrating pretty bad.



Here are some pictures after the sanding, but before the glue was mixed up.








« Last Edit: February 26, 2011, 12:27:46 PM by taylorp035 »

taylorp035

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Re: Treadmill Dyno
« Reply #53 on: February 26, 2011, 01:33:27 PM »
Here is the first video of the electric dyno in operation.  Later, we added more bulbs.

http://www.youtube.com/watch?v=dErZDp20kSM

zap

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Re: Treadmill Dyno
« Reply #54 on: February 26, 2011, 02:14:49 PM »
Nice video... you boys are having way to much fun!

924 watts =1.2hp?  How warm is the treadmill motor getting?

Once again... thanks for all the info you keep providing.

taylorp035

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Re: Treadmill Dyno
« Reply #55 on: February 26, 2011, 03:19:20 PM »
Here was the original set up with the chain.  It was getting really jumpy around 60v.

http://www.youtube.com/watch?v=5OIXyeXDMhw

Quote
Nice video... you boys are having way to much fun!

924 watts =1.2hp?  How warm is the treadmill motor getting?

Once again... thanks for all the info you keep providing.

We always have a lot of fun!  Several of the videos I will not post because something distracting happens or something goes wrong.

As for the the 924 watts, I believe the governor is way too low.  If the top rpm was only 105*33 = 3465 rpm, then it is set too low.  I know we hit at least 5,000 rpm last year in competition.  The data with the engine suggests a max rpm of 4000 rpm for extend run times.  Peak torque is supposed to be 4.9 ft*lbs at 2800 rpm.

Here is the official data:
http://www.jackssmallengines.com/bs35horizontal.html

Also, the belt was getting pretty warm, so I bet it was only 90-95% efficient.  As for the motor, I ran it at full throttle for probably 5 minutes and it wasn't cold anymore, but it wasn't hot, maybe 90 F.

I am wondering what the efficiency of the treadmill motor is.  Maybe we will hook up another electric motor to the treadmill motor and see what we can figure out.  Does anyone one have any data on this?


EDIT:  Also, would any one know if the torque required for the treadmill motor is an quadratic function?



« Last Edit: February 26, 2011, 03:26:08 PM by taylorp035 »

taylorp035

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Re: Treadmill Dyno
« Reply #56 on: February 26, 2011, 10:24:31 PM »
Here is the last video, with all 10 light bulbs. Sorry it took me so long to upload it...

http://www.youtube.com/watch?v=0y64QiC9mkA

The output was between 67-69v @ a calculated 13.6 amps. The rpm was only about 2200, so it was obvious that the treadmill motor was winning the torque contest.

taylorp035

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Re: Treadmill Dyno
« Reply #57 on: February 27, 2011, 05:19:14 PM »
I have been thinking about how I am going to find the absolute efficiency of our engines.  It will be easy to compare the fuel usages between the engines at a set power and rpm level, but actually getting a percentage is going to be difficult.

Idea #1 would be to take the hp graph from the manufacturer and compare it to the fuel usage.  This would only be accurate if our engine actually puts out what its supposed to.

Idea #2 would be to do what the wind folks do around here and make a lever arm scale thing that measures the torque.  This would only be as accurate as the scale reading * the rpm accuracy.  I'm not sure how I would find the torque, since both the engine and the motor would need to be clamped down to a table.

Idea #3 is to try to calculate the efficiency by comparing it to last year's results.  This would be an average efficiency, which isn't what I want, but it would work.  According to the numbers, it should be between 9-10% efficient, which I am fairly confident about.

Any ideas out there that I could do to find the efficiency?


SparWeb

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Re: Treadmill Dyno
« Reply #58 on: February 27, 2011, 05:46:26 PM »
Got a lathe?

On my pages, look for the alternators, the Baldor conversion, and near the end is the load test.
www.sparweb.ca

It's really really that simple.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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taylorp035

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Re: Treadmill Dyno
« Reply #59 on: February 27, 2011, 06:02:39 PM »
Well, I have the exact same scale, but the lathe may be a little tricky.  Mine at home wouldn't have enough power or clearance and the one in our lab is way too small.  We could use our mill, but I would have to put the motor in a 3 jaw jacobs chuck.  Maybe I should put it in a 5/8" collet instead.  I don't remember the hp rating on the mill, but it's 240v, so probably at least 3 hp.  The same mill at my high school had a 10hp motor.


« Last Edit: February 27, 2011, 06:30:15 PM by taylorp035 »

SparWeb

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Re: Treadmill Dyno
« Reply #60 on: February 27, 2011, 06:26:21 PM »
I watched a couple of your team videos to see how you're set up.
If the vertical mill doesn't work, you could rig up with the engine test bench you already have.  I think so at least - it would take some fabricating of a mount for the electric motor that allows it to rotate freely...  It will take some though to set it up right, but it seems like a mount for the motor like a baby cradle, whose axis is co-axial to the motor shaft would permit freedom to rotate the motor, yet keep the motor properly aligned to the motor.  Its freedom to rotate is resisted by the long-beam.  I can't tell if that came across clearly in words so just write back after trying the milling machine, if you want another option.
Depends on how badly you want the numbers.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
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SparWeb

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Re: Treadmill Dyno
« Reply #61 on: February 27, 2011, 06:27:23 PM »
Oh yeah (duh) the other way is to prony-brake the B+S motor of course!
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
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taylorp035

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Re: Treadmill Dyno
« Reply #62 on: February 27, 2011, 06:50:55 PM »
Well, we have the water break for the dyno and it is all set up and working  BUT, the water break is so uncontrollable that it will just stall out the engine and no data can be taken.  Putting the motor in the mill will be far the best option.
« Last Edit: February 27, 2011, 07:39:06 PM by taylorp035 »

taylorp035

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Re: Treadmill Dyno
« Reply #63 on: March 03, 2011, 08:14:04 PM »
Today I had a little time to mess with the dyno, so I hooked up our new analog 30 amp meter to the light bulbs.  I also hot glued all of the loose wires and things.  We maxed out  (with the governor) at 66 volts @ 16.5-17 amps.  This means there was about 2 hp at the shaft of the engine.  Interestingly, this is about 25% higher than we predicted using ohm's law.  I measured the bulbs with the multimeter today and it said 4.6 ohms, but when we do the calculations, they should be about 50 ohms.  I imagine the resistance goes up as the filaments heat up.

Tomorrow is the fun day, where we will hook up the burret to the gas line and take the governor off.  I will have to see how warm the treadmill motor gets, especially  when generating 20-30 amps for several minutes.

taylorp035

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Re: Treadmill Dyno
« Reply #64 on: March 05, 2011, 03:39:20 PM »
Hi guys, I know you guys have been waiting patiently for some results, so here they are.  I have 3 videos that really show how the whole thing is set up, the last one is still uploading.  I will get you some data, graphs, and temps of the treadmill motor in ~2hrs.

http://www.youtube.com/watch?v=6NPW412Fi1s

http://www.youtube.com/watch?v=nPyQXx92IFM

and here is the 3rd video:

http://www.youtube.com/watch?v=0Y3JSa3i5HI



EDIT:

Q:  Does the motor get hot and under what loads?

Well, we ran the engine for about 2 hr's straight at full throttle with approximately 1 minute breaks between 2-3 min long runs.  Even after a good 1/2 hr of generating 800-1000 watts, the motor was in the 110-130 degree range.  There is no fan on this motor to cool it down. 

Q:  How much power can you get out of the treadmill motor?

Haven't found the upper limit yet.  Our highest data point was at 75v @ 17.4 amps = 1305 watts, which represents 10 -300 watt light bulbs with the stock engine past the governor.

Q:  What efficiencies did we achieve?

We don't know the efficiency of the treadmill motor or the v-belt, but I assumed a constant 80% for the motor and 95% on the belt.  This comes out to 76%.

If you assume the constant 76%, the engine peaked at ~14.2% efficient + or - 0.2%.  Below or an another post, I will copy my table of data for you guys to see.

Q:  How was efficiency calculated?

The dyno was set up with the engine and the treadmill motor connected with 3" pulleys and a v-belt.  The gas was measured using a 50 cc buret connected.  What we did was we filled the buret past the top with fuel and then we started the engine.  When the fuel passed the "0" mark, we started the stop watch, and we stopped the timer after it passed the 30 cc mark.  This allowed us to get very accurate measurements, within 0.5% roughly.  While it was running, we observed the voltage and the amperage.  The data was then put into an excel sheet where all of the necessary conversions and calculations were made. 

Q:  Were the results repeatable? 

Yes,  we could do the same run several times in a row and only have variations like these -->   0.1393, 0.1431, 0.1386, 0.1414.   Usually the runs were even closer than this.

Q:  What is next to do?

Find the efficiency curve of the treadmill motor by using the vertical mill with a scale or a torque cell.  Also, I would like to get at least a few data points from the EFI engine, even if it is really hard to control.  Visual observations from the few test runs with the EFI engine showed that it really likes to guzzle gas, but nothing has been proven yet.



« Last Edit: March 05, 2011, 05:22:09 PM by taylorp035 »

taylorp035

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Re: Treadmill Dyno
« Reply #65 on: March 05, 2011, 05:43:36 PM »
Volts     
92
89
91.2
91.2
92
65.5
77.5
78.5
78
78
63.5
63
66.7
66.5
69.8
69.2
73
71
75.9
79.5
79.5
83.5
88
87.5
92
91.6
96.7
96.4
96.5
100.8
75
53.6
62
44.7
43.7
Amps   
6
5.9
5.8
5.8
5.9
5.1
10.7
10.7
10.7
10.7
16.2
16.1
15
15
13.7
13.7
12.1
12.1
10.7
9.1
9.1
7.4
7.8
7.8
6
6
4.1
4.1
4.1
2
17.4
15
15.2
13.7
13.4
Watts   
552
525.1
528.96
528.96
542.8
334.05
829.25
839.95
834.6
834.6
1028.7
1014.3
1000.5
997.5
956.26
948.04
883.3
859.1
812.13
723.45
723.45
617.9
686.4
682.5
552
549.6
396.47
395.24
395.65
201.6
1305
804
942.4
612.39
585.58
Gallons               
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
0.007925162
Seconds   
160.22
187.64
165.05
174.87
161.79
248.25
133.57
135.47
132.11
134.76
110.2
110.32
114.58
113.97
115.81
115.24
120.11
122.76
128.84
141.81
138.94
148.97
140.75
145.64
159.05
159.74
177.1
177.94
178.76
201.2

134.77
116.5
169.59
163.75
Joules/s               
6529.280526
5575.150959
6338.208579
5982.280128
6465.920798
4213.983186
7832.00813
7722.162294
7918.562758
7762.847476
9492.933992
9482.608103
9130.051719
9178.918364
9033.082859
9077.762287
8709.69383
8521.679097
8119.538388
7376.922121
7529.302763
7022.362395
7432.478337
7182.925885
6577.311071
6548.90025
5906.952716
5879.067809
5852.099608
5199.410169
#DIV/0!
7762.271469
8979.582197
6168.531906
6388.527181
Est. RPM
3036
2937
3009.6
3009.6
3036
2161.5
2557.5
2590.5
2574
2574
2095.5
2079
2201.1
2194.5
2303.4
2283.6
2409
2343
2504.7
2623.5
2623.5
2755.5
2904
2887.5
3036
3022.8
3191.1
3181.2
3184.5
3326.4
2475
1768.8
2046
1475.1
1442.1
Efficiency       
0.111239789
0.123928672
0.109810208
0.116343599
0.110457667
0.10430499
0.139315282
0.143120194
0.138681466
0.141463284
0.142585278
0.140742425
0.14418838
0.142990704
0.139292074
0.137415038
0.133441756
0.132649296
0.131607495
0.129038626
0.126427098
0.115776753
0.121515039
0.125022356
0.110427465
0.110424326
0.08831475
0.088458349
0.088958176
0.051017933
#DIV/0!
0.136286748
0.138091057
0.130626919
0.120606828
Shaft HP       
0.974006656
0.926541477
0.933352465
0.933352465
0.957773212
0.589432832
1.463215615
1.482095817
1.472655716
1.472655716
1.8151461
1.789737231
1.765387064
1.76009355
1.687325371
1.672821142
1.5585871
1.515886084
1.433007293
1.276531006
1.276531006
1.090287523
1.211156103
1.204274534
0.974006656
0.969771845
0.699573223
0.697402882
0.698126329
0.35572417
2.302678779
1.418661869
1.662869335
1.080565102
1.033258728
Notes 
Full Bunny, 3 Lights
Full Bunny, 3 Lights
Full Bunny, 3 Lights
Full Bunny, 3 Lights
Full Bunny, 3 Lights
Partial Throttle, 3 Lights
Fully Bunny, 6 Lights
Fully Bunny, 6 Lights
Fully Bunny, 6 Lights
Fully Bunny, 6 Lights
Full Bunny, 10 Lights
Full Bunny, 10 Lights
Full Bunny, 9 Lights
Full Bunny, 9 Lights
Full Bunny, 8 Lights
Full Bunny, 8 Lights
Full Bunny, 7 Lights
Full Bunny, 7 Lights
Full Bunny, 6 Lights
Full Bunny, 5 Lights
Full Bunny, 5 Lights
Full Bunny, 4 Lights
Full Bunny, 4 Lights
Full Bunny, 4 Lights
Full Bunny, 3 Lights
Full Bunny, 3 Lights
Full Bunny, 2 Lights
Full Bunny, 2 Lights
Full Bunny, 2 Lights
Full Bunny, 1 Lights
Full Throttle, 10 Lights
Partial Throttle, 10 Lights
Partial Throttle, 10 Lights
Partial Throttle, 10 Lights
Partial Throttle, 10 Lights
[/td][/tr][/table][/td][/tr][/table]


Note:  These graphs have not been corrected for the efficiency of the treadmill motor or the actual rpm.  The rpm is based on a steady 33 rpm / volt.







Some things to notice:

The efficiency went down as the voltage went up.  This is due to the higher rpms could only be achieved with a smaller load, which is less efficient.
Only 5 tests were done at partial throttle.  More of these tests would make the results better.


EDIT:
Here are some more things I found:




The 5 points that are not on the voltage vs torque curve were the partial throttle runs


« Last Edit: March 05, 2011, 06:32:45 PM by taylorp035 »