Blueprint for 150MPG+ TDI

nicklockard

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Well, it's all been done before, with technology that is 30 years old -or older.

Ford probe 5 , with it's .137cd
http://www.christies.com/LotFinder/LotDetailsPrintable.aspx?intObjectID=3942143-

TDI engine made/sold by Elsbett (that already gets around 100mpg in a Mercedes chasis) http://en.wikipedia.org/wiki/Elsbett

Hydraulic regenerative braking system (90% efficient vs electric @40%) http://www.hybridcars.com/related-technologies/hydraulic-hybrids.html

Easy- peasy to hit 150mpg! Plus it looks sexy, and seats 4-5 adults.

The Elsbett engine is intriguing, though I can hardly find much actual use or sale of it in the 'net.
 

bhtooefr

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Wonder how throttle response (due to inertia) and emissions performance (due to sealing) are.
 

Masonjar

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The second setup you are refering to is more of what I was thinking. The only drawback I can see is long drives with many hills (think driving through the rockies). You would eventually draw down the batteries and then you would be stuck at the HP the small diesel engine made at peak, minus the efficiency loss to the electric motors.
Bingo! That is why this technology is (so far) restricted to switching duties, where a smaller load is moved on the flat, and only part of the time (i.e. the engine is only moving itself a lot of the time).

Now if we could just be happy with that smaller HP output. Loco's typically are putting out 3/4 to 1 HP per TON of train weight. Of course, they are able to do this with lots of room to start and stop, and no reason to stop between destinations. So do we really need 300+ HP cars? You're not really using that power when cruising anyway... And screaming 0-60 times are really no good in stop and go city traffic.

Andrew
 

nicklockard

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You only need to make enough power to maintain 75 mph up a1% grade without assist. Assists should provide 2x that power for 2.5 minutes.

For a light, streamlined car, 20 HP, single cylinder engine at 44% TE will maintain the steady state requirement without lugging. A boosted power of 60 HP would provide plenty acceleration for light, streamlined car.


Sent from my phone. Any misspellings or grammar mistakes are my phone's fault. Go by what I mean, not what my phone says.
 

bhtooefr

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The vehicle I'm planning out - a tandem seater to reduce frontal area - will use a 28 hp 300 cc gas engine at this point.

That gives better acceleration, along with the ability to do higher speeds to keep up with traffic in more insane areas.
 

bhtooefr

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Actually, my bad, it's at 29.5 hp @ 8000 RPM, and 22.9 ft-lbs @ 6500 RPM. CVT, suboptimal for drivetrain efficiency, but at least it keeps it in the power band, and keeps things compact and cheap.

I wouldn't mind trading some horsepower for torque, and there's two engines I've thought of that could do it, although the cost will go up, as will weight and (significantly) size.

The first is the Tata 275 IDI NA, with the fuel system revamped (and potentially a different camshaft) to spin as fast as its 4-cylinder relative - out of a 702 cc 2-cylinder, it would be able to get 26 hp @ 5500 RPM and 31.3 ft-lbs @ 2500 RPM with proper fueling. (Stock, it's 16 hp @ 3200, and 27.5 ft-lbs @ 2000. But, it's half of the 475 IDI NA, so...)

The second would be getting much more into full custom territory, and would also be rather tall, but... a single-cylinder OM604/5/6.

On the 89x86.6 version, it'd be 539 cc, 23.5 hp @ 5000 RPM (before anything is done to move the rev limit up), 27.7 ft-lbs @ 3100 RPM.

On the 87x84 version, it'd be 499 cc, 21.8 hp @ 5000 RPM (and this is the bore and stroke that the OM606 uses, so you KNOW this one will rev, given how many of the things have been modded to make power at ridiculously high revs), 24.9 ft-lbs @ 2000.
 

Greenphantom

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I think 150 mpg is definitely possible with a small TDI but I agree with most that you would need as small of a displacement engine as functionally possible. The .8L CR TDI that is in the XL1 would be the best choice for the powerplant. RMR layout I would agree would be the most optimal engine an drivetrain layout.

As far as weight goes I think you need to shoot for around 1,400lbs or less.

Get the O2A CTN transmission and do a 6 spd conversion for super tall gearing in 5th and 6th for freeway cruise optimization.

Next go with some narrow low rolling resistance tires with some light wight wheels.

Next you will need to have the right aerodynamics I would say at least on par with the XLI if not a tiny fraction better couldn't hurt.

Engine optimization get rid of all the accessory belts use an electric motor and small very small hybrid battery/ultracapacitor energy bank for initial and boost acceleration only. Also make sure its capable of regenerative breaking and start stop ability. Basically instead of using a 5kwh expensive battery bank like in the XL1 we go with a 1kwh lithium iron phosphate chemistry with a descent amount of 2.7V 3000F ultracaps in series for the power boost during acceleration as well as to help buffer the battery for extended life! Using Ultracaps will also allow us to optimize our kinetic energy recuperation as we can uptake energy magnitudes quicker than with a battery. This strategy gives you a mild hybrid TDI with the best abilities of the TDI and Electric in one cost effective package. Instead of spending $8,000 to $10,000 thousand dollars on replacement batteries in say 10 to 12 years my strategy would cost under $1000 :)

ICE are least fuel efficient during initial acceleration and while at idle. So we eliminate these two fuel sapping problems for our TDI with as little electric power as possible to reduce weight and cost. We all ready know that the diesel can get better fuel economy than the vast majority of gas electric hybrids. So instead of building a diesel electric hybrid with the same strategy as gas cars with these huge battery banks build it in a way that enhances the diesel instead of trying to take it over!

So minus the .8L 2 cylinder TDI which we can not get our hands on yet I have outlined my basic strategy here for my kit car I am currently building. The difference is that I am using the 1.4L TDI engine as I am looking to build and provide something on the lines of the Opel Eco-speedster but with mild hybrid capability and more modern creature comforts. I don't know if my recipe will give me 150mpg but I will report back as things move along. It should be interesting.

It is a shame that the OP got banned as it would have been interesting to get his input as the thread progressed.

GP :)
 

steffen707

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Maybe you've read about the elio, if it ever gets built for their quoted $6,800 price, that would be amazing, but they made a tandem package to get their CdA to a 0.26 (minute 38:00 https://www.youtube.com/watch?v=R_kjyLgVi0E), that's lower than the VW XL1 at 0.279 CdA (http://en.wikipedia.org/wiki/Automobile_drag_coefficient).

Also the elio is suppose to weigh in at 1200 lbs. So if you could get the 0.8 liter diesel of the Xl1, throw it in an elio, maybe you can hit the 150mpg; however, people are bawking at Elio for their claimed 84mpg, and that's with a direct injection motor designed by the same company that made the bugatti veyron engine. (that is what i read, can't find the link though, but their website doesn't say its direct injection)

I just don't know if a diesel of similar size is going to almost double the expected 84mpg that the efficient 55hp gas engine can make. I suppose you get rid of the A/C, power steering (if its even on there) and then make it regenerative braking and engine stop at standstill (don't remember what that's called).

I've read some guys on ecomodder making their first gen insight get 100mpg, so if you cut the car in half make it tandem, lighter yet by like 500-600lbs and make it a diesel hybrid, i suppose you could hit 150mpg.
 
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bhtooefr

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I was under the impression that Elio's motor was currently specced at 55 hp, 55 ft-lbs, 900 cc, SOHC, port injection.

In any case, there's other 800 cc diesels available. One of particular interest is the Mercedes OM660, which is used in Smart cars, and has even been sold in North America (if not the US). Should be quite a bit lighter than the VW 800 cc engine too. The output on the Canadian one is 40 hp, 74 ft-lbs, and the current version of the engine used in Europe is 53 hp, 96 ft-lbs.
 
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steffen707

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I was under the impression that Elio's motor was currently specced at 55 hp, 55 ft-lbs, 900 cc, SOHC, port injection.

In any case, there's other 800 cc diesels available. One of particular interest is the Mercedes OM660, which is used in Smart cars, and has even been sold in North America (if not the US). Should be quite a bit lighter than the VW 800 cc engine too. The output on the Canadian one is 40 hp, 74 ft-lbs, and the current version of the engine used in Europe is 53 hp, 96 ft-lbs.
I know it said port injection, but in that youtube video https://www.youtube.com/watch?v=R_kjyLgVi0E I think he says it will be direct injection, and I think they talk about the same engine supplier for bugatti veyron is making the elio engine. IAV?

those 800cc engines sound awesome. 53hp and 96ft/lbs? That's a ton more torque than the elio engine of similar displacement.
 

bhtooefr

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IAV is the design firm that Elio hired to design it. They'll use someone else as the manufacturing partner.

And, IAV is essentially Volkswagen's in house engine consultancy (it's slightly more complex than that, but that's the gist of it), which is why they have done the Veyron engine. This is scary, because Elio is going with timing chains, on an engine basically designed by VW.

Honestly, Elio could do a lot worse than buying OM660s from Mercedes, and modding them to fit their chassis. And, Elio only has to meet motorcycle emissions, which means they're about in the same emissions class a 1Z or at worst ALH had to meet.
 
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nicklockard

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The Elio's IAV designed engine also appears to have cam phasing based variable valve control, presumably to broaden the torque curve in order to better match actual road needs. It also has a unique long runner to log to runner based intake manifold, which seems to be designed to increase volumetric efficiency across the broadest range possible for a 3 cylinder and to work with the variable valve timing.

I also wonder why they didn't just purchase some OM660's except for cost.

My modeling of the Elio using the Road Load Calculator in my signature line, accross multiple driving cycles, says the 84 mpg highway is indeed achievable, provided they get the tires right! for the Elio, rolling resistance will actually dominate over aerodynamic resistance for the majority of driving cycles--suprised me, but do the checks yourself.
 
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steffen707

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I had a civic VX and had an mpguino to calculate MPG of mods I did. When I changed from the crappy tires I had, to 1st gen Honda Insight LRR tires and inflated them to 50psi, I got a 10% increase in mpg, from 50 to 55. That's a lot.

Going from 20-22 is much easier than getting an extra 5mpg out of an already efficient vehicle.

LRR tires are huge, hopefully they invest some time into that, or at least use off the shelf awesome LRR tires.

I read they didn't want a diesel because Americans generally think diesel is loud and bad for the environment, also gas is still cheaper. Its hard to weigh the pros and cons though. 84mpg will already almost double most american's vehicles as is. There is a stereotype to diesel, but how much are they investing in creating their own 3 cylinder? Will it pay off in the long haul to have high up front costs and lower variable costs, or have no up front costs and higher variable costs with the OM660?
 

puntmeister

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Interesting vehicle (the Elio). Given its low cost - $6,800, it may actually succeed.

It works as a second vehicle - to cover daily commutes - but doesn't work as a family car - not even for a very small family.

Basically, its an enclosed motorcyle - at which point, the 84 mpg doesn't sound nearly as impressive (an 84 mpg car sounds outstanding - an 84 mpg motorcycle sounds about normal).

A diesel engine would improve the mpg a good bit - but would also jack up the purchase price. If the Elio succeeds, it will be in large part because of the low purchase price.

From a business strategy viewpoint, it makes sense to come out with something like this - low cost, potentially broad appeal - to try and gain a quick foothold. Then, once they have gained some level of acceptance, come out with more advanced models, with better MPG, at a higher price point. Basically, kind of the opposite of Tesla's strategy (not knocking Tesla, somewhat different dynamic).
 
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bhtooefr

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Although an 84 mpg motorcycle or scooter has basically no weather protection, no crash safety, doesn't balance itself, and is probably under 250 cc. This has weather protection (and even AC), it has crash safety, and it may well be cheaper to run (motorcycle tires ain't cheap).
 

nicklockard

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Very few motorcycles are even remotely capable of 84 mpg...as bhtooefer said, something very small displacement that tops out at 50 mph or so. The "average" 500cc to 1000cc motorcycle will get more like 35 city/ 45 highwway, unless you drive very slowly.

My Sprint ST with me on it has ~ 8 ft2 of area * Cd of about 0.65 or 5.2 ft2 effective.
The Elio probably has 9.5 ft2 * Cd of about 0.22 or 2.1 ft2 effective. Hell, even if they don't try very hard to optimize Cd and only get 0.29, that'll still get them to 2.8 ft2, which is a little over HALF of me on my motorcycle.

My prediction: the Elio will CRUSH just about any normal motorcycle (one that is capable of going speeds where aerodynamics actually matters, that is) in fuel economy.
 

nicklockard

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Oh, and in the same Road Load Calculator, you can play around with different engine efficiencies. A Tdi with net thermal efficiencies around 37-41% would make a healthy bump in fuel economy over a best-case gasoline engine.

I figured they just don't want the cost of building and servicing diesel engines, which is much more expensive, sadly. Unless they'd be willing to develop an OPOC design of ~35-45 hp, I don't think it's going to happen anytime soon.
 

puntmeister

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I've driven 110cc scooters, which easily drove 60 mph, that got 140 mpg - and that's with absolutely no effort to save fuel - often driving with two people, all rapid stop/start city driving, etc.

Totally unavailable in the U.S., but ubiquitous in Asia - cost: $1,400. Cheap Chinese? Nope. Honda.

But, yes, like I mentioned - motorcycles/scooters aren't covered. Hence, my original point, the Elio is basically a COVERED motorcycle.

As for the cost of motorcycle tires - I believe I paid something like $12 for the scooter tires. Again, that's in Asia - in the U.S., you could expect a higher price tag. But what's to say the tires on this thing will be cheap? I would suspect, as mentioned above, the tires will be a very specific design, to achieve optimum mpg - which will mean: expensive.

I'm not out to knock the Elio - I hope it succeeds. It will make a lot of sense for a lot of people - who drive 5 seater cars with just the driver, no passengers, and nothing more than a briefcase, for 90% of the miles.

The biggest obstacle will be attitude. I was one of the first to get a Geo Metro. I can't tell you how many people had the attitude of "I wouldn't be caught dead in one of those". That mentality is pervasive - gun toting, arab hating, SUV driving hypocrites.
 
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Lensdude_com

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My prediction: the Elio will CRUSH just about any normal motorcycle (one that is capable of going speeds where aerodynamics actually matters, that is) in fuel economy.
...I would like to see BBC's Top Gear do their own brand of testing to determine a winner then give Elio to The Stig for a hot lap around their track :D
 

Greenphantom

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Elio has some things going for it for sure. I think the low cost potential they are marketing would be great if it ever becomes reality. They claim its a 2 seater but man good luck getting in that back seat LOL! I have always been partial to the 3 wheeled design but personally I like the car look vs the trike look. Plus you get better cargo, safety, aero, and looks with a 3 wheeler that more resembles a modern car.
The OP talked about hitting 150mpg there is a vehicle I found that did it with a small gas and diesel engine at 55mph and 56mph respectively. This vehicle is a plans built car! I have not purchased these plans nor will I but this gives you an idea of what it might take design wise to break 150mpg. Supposedly it still holds the records for gas and diesel fuel economy at legal road speeds. I found it interesting that the gas actually got better fuel economy than the diesel engine version! I do not know what gas and diesel engines were used in the vehicle but I would be curious to find out.
Here is the link = http://www.canosoarus.com/03CalifCommuter/CalCom01.htm

GP..
 

Greenphantom

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Somebody talked about the Smart car 800cc engine as a possible engine option to break 150mpg. I think if we go off engine only than yes we have a chance. The problem is with this option is that you have to use there transmission! You can not use a different transmission with the Smart cars. There control electronics are all meshed together and if you do not have there transmission you will not even be able to fire up the engine. This I thought kind of sucked when I was looking into it as my engine source. There transmissions are also known to be not the best either so this kind of made me turn my back from it. Not to mention I am just more biased to our TDI engines :)

There is a guy who retrofitted his car with this engine here in the states and achieved over 100mpg with it. Also in Europe the Jetcar uses this engine transmission package. The Jetcar also gets over 100mpg!

Here are the Avion Link = http://www.100mpgplus.com/articles/newspaper/article_0001.html

Here is the Jetcar Link = http://www.jetcar.de/index.php?link=75

GP..
 

Greenphantom

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The car that has always inspired me was the Opel Eco-Speedster = http://oppositelock.jalopnik.com/why-the-opel-eco-speedster-is-the-greatest-car-youve-n-997758135
Unfortunately they only made 3 of these cars and there is zero chance to buy one. So this is the reason I decided to design and now start building my kit car. The Opel Eco-Speedster achieves awesome fuel economy and performance from its 1.3L CDTI. Now its no where close to the fuel economy the XL1 hybrid offers. So my thought is create something that is some where between the two in combined fuel economy and with the same level of performance as the Eco-Speedster.
I think it would absolutely be awesome to break 150mpg but I think it would be even better to do it in a car that can do it at modern freeway speeds. I think it would also be cool to do it in a car that has some balls so to speak. The Eco speedster broke 17 world records for its engine class 1100cc to 1499cc turbo diesel class and had a top speed of 155mph! It did 0-60mph in 8.8 seconds. The car averaged over 100mpg and got over 35mpg at speeds well over 100mph.
To me this car represents something that would be a little more appealing to people if the cost was right and we modernized it a little. So this is what I have set out to do essentially because I want a car that not only has fuel economy but also great performance at a price point that is doable even for the average Joe! I know I could never afford the XL1 $150,000 price tag or purchase one of the 3 Opel Eco-Speedsters but maybe just maybe I can take some cues from the XL1 and Eco-Speedster and come up with my own superior Speed endurance hyper car that I can show others how to make also.
Will it be able to do 150mpg combined like what the OP had laid out? I think with the hybrid drive I can't see why not!
GP..
 

bhtooefr

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They claim its a 2 seater but man good luck getting in that back seat LOL!
From everything I've heard, it's not any worse than a 2-door Mk4 Golf in that respect. Which isn't great, but it's doable.

The problem is with this option is that you have to use there transmission! You can not use a different transmission with the Smart cars. There control electronics are all meshed together and if you do not have there transmission you will not even be able to fire up the engine. This I thought kind of sucked when I was looking into it as my engine source. There transmissions are also known to be not the best either so this kind of made me turn my back from it. Not to mention I am just more biased to our TDI engines :)
Then explain the Track T-800 CDI. Has the OM660, doesn't have the Smart transmission. ;) Or, Neil Laughlin's Triumph Tiger with an OM660 swap. Same deal.

I THINK both are using standalone ECUs, though, which helps a lot - they just treat it as a common rail diesel (which it is) and buy an aftermarket ECU set up to drive a 3-cylinder common rail diesel, and tune that. And, if you don't mind some shift harshness, the first-gen Smarts drive better with a chiptune allegedly (the transmission computer is the ECU), and the second-gen Smarts can have their transmission computer tuned separately from the ECU.

As far as the Opel Eco-Speedster... well, underneath, it's just a Lotus Elise, and it's theoretically possible to get new fiberglass panels for an Elise molded, and strip some weight here and there...
 
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Greenphantom

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Ya If those cars you speak of are using the Smart CDI then they would need a standalone ECU to use a custom transmission. Its very possible as there are some Diesel ECU options I have seen but spendy! I think anything is possible with enough time and money theoretically. I personally really like the Smart CDI and you are correct the first gen transmissions are good tuned. They also will give the best fuel economy over there newer versions. I also like the fact they played with some mild hybrid ideas.

The deal breaker for me not using the smart drivetrain was the engine configuration stock and if I wanted to change things up it would take time and money to do so. I wanted a mid engine rear wheel drive like in the Opel Eco-Speedster. The chassis I am using pretty much dictated that. Now I think somebody could do like a locust build and use a Smart and get some good results with good aero work.

GP
 

bhtooefr

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Those are motorcycles, not cars, actually.

As far as doing mid-engine RWD... the Smart is pretty much already that layout, although with the engine leaned back 50 degrees (so it's JUST rear-engine by mass distribution).
 
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