TerraLiner:12 m Globally Mobile Beach House/Class-A Crossover w 6x6 Hybrid Drivetrain

biotect

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1. AARCWPOM: Active-Adventurous Retired Couples with Plenty of Money


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Hi Iain,

That's a simply brilliant acronym: ORCWPOM: Old Retired Couple With Plenty of Money....:sombrero:

However, I am not so fond of "Old" in the acronym (if that's what "O" stands for?), because I've been imagining my couple as active and adventurous types who have kept very fit. "Old" suggests perhaps infirm or invalid, no longer physically autonomous, no longer able to climb stairs, and so on. Whereas I've been imagining
a very sporty, “fit” sort of couple, of the kind who have always been active, and who want to remain active. So instead, a better acronym might be AARCWPOM: "Active-Adventurous Retired Couple With Plenty of Money".

For instance, perhaps the husband has been taking hormone supplements since age 50, has continued working out in a gym or swimming regular laps in a pool, and even at age 75 he resembles Dr. Life, and other similarly super-fit older guys – see https://en.wikipedia.org/wiki/Jeffry_Life , http://www.bbc.com/news/magazine-21151163 , http://www.thetimes.co.uk/tto/magazine/article3060467.ece , http://www.telegraph.co.uk/lifestyl...879/Has-the-fountain-of-youth-been-found.html , http://knpr.org/desert-companion/live-you-long-time-dr-jeffry-lifes-quest-conquer-getting-old , http://www.drlife.com , and http://www.drlife.com/meet-dr-life/ :



PD47922981_Dr-Life_2025124b.jpg 51666195.jpg Jeffry-Life.jpg
TMM18DRLIFEA_a_168549c.jpg 47wje5b4pc2a2bxk71xzokq0q.jpg TMM18DRLIFEC_a_168551c.jpg





At 75 Dr. Life is now more fit and in better shape than most 30 year olds.


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biotect

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Or perhaps the husband resembles Richard Branson, in these publicity-stunt photos and explanatory video:



kitesurf6-14343.jpg Alt_Branson0705121.jpg richard_naked_lady_kitesurfing_necker.jpg




Note that Richard Branson is very happily married, he has a close-knit family, and in the morning he has been waking up to the same woman for decades -- see for instance http://www.virgin.com/richard-branson/behind-every-man-theres-a-great-woman , http://www.telegraph.co.uk/finance/...-is-better-at-managing-our-familys-money.html , http://www.theguardian.com/lifeandstyle/2014/sep/19/richard-branson-my-family-values , http://www.virgin.com/richard-brans...ed-joan-a-virgin-island-an-unacceptable-offer , and https://www.youtube.com/watch?v=8CAgx-yIBXw .

The following video is merely tongue-in-cheek, again, a bit of a publicity stunt to promote Necker Island:






Richard Branson is not a billionaire "player" at all; he's a family man. But he is very physically fit, very fond of kite-surfing, and if any 60-something billionaire could have posed for the above photo-ops, it would be Branson.

Or I am designing for the rich guy who had a financial windfall at age 40 or 50, and who can spend the next 30 years sojourning around the world with his wife.

By the way, there is always a wife in the picture, because most financially successful men are happily married, just like Branson. This is a basic sociological datum that is not widely known. It's probably a chicken-and-egg problem: which came first, a good marriage and happy family life, or financial success? Undoubtedly the two mutually support and reinforce each other, in a virtuous feedback loop -- see https://www.nytimes.com/books/first/s/stanley-millionaire.html and http://indy-biz.com/danpdf/dlArt75.pdf .


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biotect

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2. The TerraLiner: Dedicated to the Active and Adventurous Elderly of Duck Key, Florida


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When I was a kid growing up, most of my vacations (including the summer) were spent on an island in Florida: Duck Key in the Florida Keys, an island packed with sporty retired people -- see http://www.clubduckkey.com and https://www.google.co.uk/maps/place...2!3m1!1s0x88d0d177df110247:0x5ac8f4d458180ea3 . On Duck Key I got to know lots of retired people who were still windsurfing at age 70, scuba-diving at 75, and still out on the reef fishing every day at 80; retired people who were absolutely determined to never enter an old-age home before they finally passed away. These retired people were great, simply fantastic, and if I were to dedicate the TerraLiner to anyone, it would be to the “active elderly of Duck Key, Florida”:



Untitled2.jpg Duck Key Aerial.jpg Duck-Key-Florida-Map.jpg
duck-key-florida-our.jpg 2481346.jpg 2441037.jpg
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Retired people today are very different than retired people 50 years ago. This is something that sociologists, demographers, marketers, real-estate developers, and real-estate agents have long recognized. For one thing, retired people today live much longer. They can look forward to another 30 years of fun, active living, if they have kept fit and healthy, and have kept up a regular exercise regimen. The wealthier ones also tend to be sitting on huge piles of accumulated capital, so they can afford to buy homes that cost millions. Whereas even young doctors, lawyers, or executives simply cannot. The big homes with big boats in the images above are not owned by people in their 30's or 40's, and not even in their 50's. Rather, most are owned by retired people in their 60's, 70's, and 80's. And the same is true for most (albeit granted not all) luxury Class-A American motorhomes.

Think of it this way: even Richard Branson talks eloquently about how at the start of his career, he wasn't sure whether Virgin Records would work out. When he bought Necker island, he put in a ridiculously low offer, much lower the asking price. A year later they called him up because he was the only one to offer anything at all for the island, and it became his. But he had to wait a bit before developing it, and Necker Island was built up only gradually, as his businesses flourished and became the "Virgin Empire".

The fishing boats in front of Duck Key homes also signal very loud and clear why these people chose to retire to the Florida Keys, as opposed to other oceanfront communities elsewhere in Florida, or retirement communities in Arizona. In a word: Fishing.

It's relatively easy to get to the reef and fish in the Keys. In the opposite direction, passing under the bridges of the Overseas Highway, it's very easy to reach Florida Bay and the islands of Everglades National Park -- see https://en.wikipedia.org/wiki/Overseas_Highway and https://en.wikipedia.org/wiki/Florida_Bay . Until recently the fish were abundant, but fishing bans are now in effect in many months, because stocks are in serious decline -- see http://www.nytimes.com/2010/03/31/us/31fish.html?_r=0 . The average size of big trophy fish is also declining -- see http://scienceblogs.com/guiltyplanet/2009/04/27/fish-photos-from-florida-keys/ , and http://www.livescience.com/3342-photos-document-dramatic-decline-trophy-fish-size.html . Although I am now a Buddhist, when I was a kid I caught and filleted literally thousands of fish: everything from grunts, grouper, snapper, and hogfish caught inshore or on the reef, to mackerel, bonito, cobia, wahoo, swordfish, and dolphin fish (i.e. mahi mahi) caught via trolling. I was also especially fond of fishing for tarpon in Florida Bay. But with tarpon it's the thrill of the chase, and tarpon are strictly catch-and-release. Back then you didn't even need a fishing permit, whereas now things are much more tightly controlled. Perhaps because I am now a Buddhist, my dreams are haunted by fish looking up at me in astonishment as they gasp for water, flopping around on the bottom of the boat....

Unfortunately the reef is dying, and may be completely dead in as little as 50 years -- http://www.sun-sentinel.com/local/palm-beach/fl-coral-bleaching-20150928-story.html and http://articles.chicagotribune.com/...reefs-dollars-into-south-florida-florida-keys . Florida Bay is also dying, because nitrogen runoff from agriculture north of the Everglades reaches the bay, and creates huge algal blooms that swallow up all the oxygen, making it impossible for anything else to live. The Everglades -- a vast slow-moving "river of grass", 60 miles wide, 100 miles long, and 6 inches deep -- was once sufficiently replenished on an regular basis when Lake Okeechobee flooded its southern bank. When the river of grass reached Florida Bay it mingled with salt water to create one of the most diverse and productive estuarine environments on earth. But in the 20th century engineers constructed a berm across the southern shore of Lake Okeechobee to stop its flooding, farms were established south of the lake, and canals began diverting much of the water to support agriculture and urban populations in South Florida. With all that farmland now in place south of the Lake Okeechobee, the Everglades have become an enormous sewer for agricultural chemicals, and the desertification of the "the river of grass" is a real possibility -- see https://en.wikipedia.org/wiki/Florida_Bay , https://en.wikipedia.org/wiki/Everglades , and https://en.wikipedia.org/wiki/Lake_Okeechobee .

So who knows if the "active and adventurous" retirement community of Duck Key will still be flourishing 50 years from now, once the surrounding ocean has become as dead as much of the Mediterranean coastline in Italy, France, and Spain. And 100 - 150 years from now, all of it will be under water because of global warming.

In any case, such environmental horror stories aside, in future let's use the acronym AARCWPOM: "Active-Adventurous Retired Couple With Plenty of Money". Let's ditch the "O" at the beginning of your acronym, Iain, unless it stands for something other than "old". Calling retired people "old" is a bit age-prejudiced, if only because the active elderly do not think of themselves as old, just because they are retired. Many of them also don't like to be called "old" because they feel newly young again, once retirement begins. "Old" is really more a state of mind than a quantitative age-category. Or at least that's what the active elderly on Duck Key taught me.


Note: Duck Key has changed since I spent lots of time there as a kid, because the Hawks Bay resort built condos on what was formerly a golf-course, and has thereby massively expanded the real estate available, especially at the lower end of the market. Duck Key is now much more accessible to families with kids, and much more tenable as a weekend family vacation destination for those who live in Miami. The houses on Duck Key that have ocean-views still cost millions, but it's now possible for families with very young children to buy vacation homes on the island that cost a fraction of that.

Also note that the "Middle Keys" are great in the summer. During the summer the humidity on mainland Florida becomes unbearable, and enormous cumulous clouds form over the mainland due to of adiabatic cooling. The hot ground generates thermals, and as air rises it cools, forms clouds, and dumps loads of rain. By way of contrast in the Middle Keys, where Duck Key is located, there is not enough land relative to the surrounding water to generate clouds and rainfall. Climatologically speaking the Middle Keys have a semi-arid or even a near-desert climate. The humidity remains very low, even during the summer. Whereas further south Big Pine Key is large enough to generate some adiabatic clouds and rainfall of its own. For me summers were spent always marveling at the enormous 35,000-foot high wall of cumulous clouds hovering over the Everglades and mainland Florida, as I basked in endless sunshine and low humidity on Duck Key.

Incidentally, this is another reason why retired people love Duck Key: because the humidity level year-round is as dry as Arizona. If they suffer from arthritis it's a major plus. But unlike Arizona they won't be gazing out at boring desert landscapes, but rather, they will be gazing out at the ocean, if they have an ocean-view property. And on Duck Key even the ocean-view properties have canals in front, where they can park their boats.



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3. Designing for the World's "Frugal Millionaires"


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There is a great deal of mythology surrounding wealth, much of it created and fomented by the media. Particularly egregious is the myth that most millionaires "make it" and become rich before they turn 30. This is sociologically and statistically false -- see http://uk.businessinsider.com/it-ta...t-least-32-years-to-get-rich-2015-3?r=US&IR=T . Lots of studies have shown that perhaps 80 % of self-made millionaires (i.e. those who did not inherit their wealth), only made their first million after age 50. So too, there's lots of evidence to suggest that the secret to becoming a millionaire is not how much one earns, but rather, how much one saves -- see http://livingstingy.blogspot.it/2011/05/millionaire-next-door.html . Furthermore, millionaires also tend to be owners of small businesses that are on the face of it quite humdrum and boring. The owner of a chain of used car dealerships is much more likely to be a millionaire than a high-flying doctor or lawyer. And so too, the owner of two or three small local hotels, or a small local contracting business, or three or four funeral homes, or a local sawmill.

Typically these small-business owners will have less education than the "professional class" of doctors and lawyers, and the latter will often earn higher salaries. But the high-consumption lifestyle and elaborate expectations of doctors and lawyers often mean that they save very little, so they do not become millionaires. About half of those who are millionaires continue to live in working-class or middle-class neighborhoods, and not prestigious neighborhoods. And as already stated in the previous post, the typical millionaire marries just once, often to his high-school sweetheart, and has a close-knit family -- see http://www.thomasjstanley.com/2009/12/the-low-profile-millionaire-next-door/ , http://www1.cbn.com/portrait-millionaire , http://www.amazon.com/The-Millionaire-Next-Door-Surprising/dp/1589795474 , and http://www.nytimes.com/2015/06/06/y...-the-splurges-even-as-a-millionaire.html?_r=0 .

People today do not like hearing sociological facts such as these, because they make wealth seem less glamorous and magical. The media tend to focus their attention only on the handful of tech-entrepreneurs who get rich quick when they are young, or the handful of people who get rich doing something fun and creative, like acting or directing movies. The media also focus their attention on the comparatively small number of people who are truly rich, those who have 30 million or more in assets.

But while the mean or "average" wealth of an American millionaire is 3 million USD or thereabouts, the median or 50th percentile is much lower than that, somewhere between 1 - 2 million. The average skews things upwards because of billionaires like Warren Buffet. As one moves up the wealth pyramid the number of people shrinks logarithmically. Of the 30 - 32 million people worldwide who are millionaires, 28 million have between 1 - 5 million in assets; another 2 million or so have assets between 5 - 10 million; and 1 million have assets between 10 - 50 million. According to the Financial Times, there are 199,235 “ultra high net worth” individuals worldwide, of the kind that money-managers like to cultivate, who have assets of 30 million or more – see http://www.zerohedge.com/news/2013-...net-worth-people-world-over-30-million-assets . Let's call it 200,000, and these constitute just .002 % of the world's population, or 1 in 35,000. Of those who have 30 million or more, 85,000 have between 30 and 50 million, leaving about 115,000 people worldwide with more than 50 million in assets – see https://en.wikipedia.org/wiki/Ultra_high-net-worth_individual and http://www.wealthx.com/wealthxubswealthreport/ . This works out to 1 in 60,000.

So when I think of the TerraLiner's target market, I am thinking of "low-flying" and "frugal" millionaires in the 1 - 5 million range. Traveling by motorhome is a potentially low-cost form of travel, at least once the initial capital cost of the RV is out of the way, because the motorhome serves simultaneously as hotel and restaurant -- see http://www.rvia.org/?ESID=vcosts . Motor-homing with a large Class-A is a form of travel that often appeals to "frugal millionaires" who have finally retired, want to travel, want to travel comfortably and slowly, and who also want to continue cooking and cleaning for themselves, in their own home.

I want to address the needs, wants, and preferences of these people, and no others. I want to address their financial capacities, their level of free time available, their calendar, their sense that they can “slow down” and “slow travel” the world not just for 2 years, but rather, for 20 or 30 years.


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biotect

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4. Combined TerraLiner and TOAD Trailer Weight: 30 - 32 Tons


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Also, very much liked your brilliant deduction from a Newell. I hadn't quite thought of it that way, but you are right. The performance of the TerraLiner should be the same as the performance of a Newell motorhome, because the intended market is the same. Terrific insight.

But also please remember, the TerraLiner will be smaller and lighter than a Newell. A Newel motorhome is 13.72 m long, and slightly wider and slightly taller than the TerraLiner will be. A Newell also has side-lockers that reach down very low, with perhaps at best 20 - 30 cm of ground-clearance. Hence, the TerraLiner's overall volume will be considerably smaller than a Newell. In post #1961 I calculated that the TerraLiner's volume will be about 77 % of the volume of a Newell. So even though a Newell weighs 29 tons, scaling down appropriately, the TerraLiner should weigh 22 tons. And if we factor in certain extras like drop-down decks, once again, a maximum of 24 tons, and no more. See http://www.expeditionportal.com/for...igid-Torsion-Free-Frame?p=1962810#post1962810
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So please, let us finally and forever abandon 30 tons, when talking about just the Terraliner, separate from the trailer. The TerraLiner alone, by itself, will not be that heavy.
campo cited a figure of 30 tons because that's the size of a truck that he once drove:


From my driving experience I think that I can maintain on the flat a modern truck combination of 30 tons at speed 90km/h with something between 200 to 250 hp. I did never measure it.


But please let's do stick to stick to 21 - 23 tons, and 24 tons maximum, for all of the good reasons that I spent lots of posts documenting.....:)

On the other hand, it would be very accurate to think in terms of 30 - 32 tons, when we're talking about the TerraLiner + the TOAD trailer, because 22 - 24 tons for the TerraLiner + 8 tons for the TOAD trailer = 30 - 32 tons. If that's what you meant by 30 tons, then no worries. I just wanted to be very clear what the parameters are, and want other thread participants to be clear about the same:


TerraLiner: 21 - 23 tons, and 24 tons maximum

TOAD trailer: 8 tons

TerraLiner + TOAD trailer: 30 - 32 tons


Otherwise, I really liked your reasoning about possible performance scenarios. For instance, I liked the idea that on a rare, 15 % grade the TerraLiner should not be expected to do as any better than other big trucks on the road. I also liked the idea of designing for a 75 % (but not 50 %) drop in battery capacity. Almost all of the operational parameters that you have stipulated make sense to me, except for that possibly inexplicable return of an arbitrary, empirically unjustifiable, and totally gratuitous 30 ton figure.....
:sombrero:...That is to say, if this was a weight figure for the TerraLiner alone, without trailer. :ylsmoke:

In short, the "performance" characteristics of the TerraLiner should be more or less as you describe them, and we can use them as a starting point for further engineering discussion of the power requirement.



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5. The Size of the Electric Motors


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Here are some more observations/questions.

If the Newell has a 600 HP engine, or 447 KW, minus a 30 % power loss for the Allison transmission, this should then give us an accurate size for the electric motors: 447 KW x 0.70 = 312 KW. So either the TerraLiner needs three 104 KW electric motors, or it needs six 52 KW electric motors. Granted, with the three-motor configuration, there would still be power loss due to three cross-axle transmissions. So the motor size would have to be scaled up accordingly, to take into account that power loss.

Furthermore, I am personally inclined to want to equip the TerraLiner with slightly more power, somewhat analogous to the largest Volvo trucks that now come equipped with 750 HP engines -- see http://www.therichest.com/luxury/auto/the-most-powerful-trucks-in-the-world/ and http://www.truckinginfo.com/article...-truck-and-swedens-longer-heavier-trucks.aspx :



[video=youtube;sHtUkP94RrI]https://www.youtube.com/watch?v=sHtUkP94RrI [/video]
[video=youtube;uBMa_rUUk90]https://www.youtube.com/watch?v=uBMa_rUUk90 [/video]


So if instead we imagine the TerraLiner as having electric motors equivalent to an 800 HP diesel engine, minus 30 % for a transmission, then we get a figure of 560 HP, or 417 KW. This means that six electric motors would have to be 70 KW each, and three electric motors would have to be 140 KW each. Again, in the three-motor configuration there's power loss for the cross-axle transmission, but as Haf-E has already suggested, that power loss would be less than the 30 % typically lost in the transmission of a truck.

I wonder how much the power loss from three cross-axle transmissions loss would be? 10 %? As little as 5 %? As much as 20 %? Haf-E, if you are reading this, please chime in!!

Until we have a reasonably good figure for the power loss from three cross-axle transmissions, let's stick instead to the six-motor configuration, with six electric hub motors, each rated at roughly 70 KW for maximum power, or 420 KW in total.


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biotect

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6. 80 KW Hub Motors on IVECO Electric Trolley Buses


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Incidentally, the electric trolley buses made by IVECO, buses that have been operating successfully in multiple European cities for more than a decade, have 2 hub motors rated at 80 KW each if they are 12 m buses, and 4 hub motors if they are 18 m articulated buses:



IRisbus_TWG_lyon1.jpg Grand_Irisbus32.jpg Grand_Irisbus34.jpg


And for a YouTube playlist, see https://www.youtube.com/watch?v=O3bDAFDPe7I&list=PLfp_nxCjWatfxyRCCKsct4-eUa1eCBUp_ .


In other words, in an 18 m configuration analogous to the TerraLiner, IVECO's electric trolley buses will have electric hub motors rated for 320 KW in total. So if IVECO thinks 320 KW is necessary for the electric motors on an 18 m articulated bus, then my guess-timating 420 KW for the electric hub motors in a 6x6 TerraLiner would seem reasonable enough: a TerraLiner designed to travel bad roads and occasionally off-road, onto a farmer's field.....

Here it's worth noting that in its earlier buses built for Milan, shown in the second image above, IVECO fitted them with four 60 KW motors. Whereas in the more recent buses built for Bologna, IVECO fitted them with four hub motors that can provide 60 KW of "continuous power", and 80 KW of "maximum power". The general trend in the size of hub motors in electric trolley buses seems to be upwards.....:ylsmoke:



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7. Hydro-Drives for the TOAD garage trailer


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It's also important to always remember that the TerraLiner will be towing a TOAD trailer, and that the entire configuration will be 18.75 m long.

As for the drive-train of the TOAD trailer, here I would go with a "hydrostatic" drives as per the Kiravan, so that the trailer has some degree of independent mobility, i.e. the ability to reposition itself on a beach or a piece of farmland -- see http://www.truck.man.eu/global/en/f...gy/man-hydrodrive/man-hydrodrive-special.html , http://www.truck.man.eu/global/en/f...technology/man-hydrodrive/MAN-HydroDrive.html , http://www.truck.man.eu/global/en/f...gy/man-hydrodrive/man-hydrodrive-special.html , and http://www.truck.man.eu/man/media/e...ess_website_truck_master_1/MAN_HydroDrive.pdf . These hydro-drives would be driven by an electric compressor, in turn powered by solar cells on the trailer's roof.

Here are some videos of MAN's "Hydrodrive" for trucks:



[video=youtube;Vib4f79v4kQ]https://www.youtube.com/watch?v=Vib4f79v4kQ [/video] [video=youtube;T0Tt48h_7fw]https://www.youtube.com/watch?v=T0Tt48h_7fw&index=5&list=PLfp_nxCjWatfxyRC CKsct4-eUa1eCBUp_[/video]
[video=youtube;3JDhRP0VHKg]https://www.youtube.com/watch?v=3JDhRP0VHKg&index=14&list=PLfp_nxCjWatfxyR CCKsct4-eUa1eCBUp_[/video] [video=youtube;e5daJPuvhQM]https://www.youtube.com/watch?v=e5daJPuvhQM&index=7&list=PLfp_nxCjWatfxyRC CKsct4-eUa1eCBUp_[/video]



For a YouTube playlist, see https://www.youtube.com/playlist?list=PLfp_nxCjWatfxyRCCKsct4-eUa1eCBUp_ .

But otherwise, in the course of normal driving the TerrraLiner would tow the trailer, and the trailer would not have its own, independent electric hub motors. When driving a bit off-road to get to the farmer's field, the trailer's hydrodrives would kick in, helping things along. Off-road driving to the farmer's field would be very low-speed in any case, and the hdyrodrives would be perfect for that. This seems to me the simplest arrangement, all things considered.

However, if anyone thinks that a different combination of electric hub motors + hydrodrives would be better, do suggest alternatives. For instance, the Kiravan seems to have a somewhat complicated combination of conventionally driven axles + hydrostatic motors -- see http://kiravan.net/tractor/ and http://kiravan.net/trailer/ .


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8. Might 240 KW in total for the Electric Motors prove sufficient? Probably not.


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Also note that the Van Hool, "dual mode", articulated electric trolley bus that I cited earlier is 18 m long, has a back-up 100 KW diesel-electric generator so that it can run independently of an overhead catenary electric grid, and has just one electric motor driving the second axle, rated at 240 KW:



ATM_Milan_Trolleybuses_-_Main_Features_and_Experiences.jpg ATM_Milan_Trolleybuses3_-_Main_Features_and_Experiences.jpg



It cannot be emphasized enough that these electric trolley buses are not vaporware. The bus above is a real bus, currently in service in Milan. That's why I explored such buses at such length, once I discovered them.

Now granted, these are buses designed for urban areas where the roads tend to be flat, and very little climbing is required. They are also buses with huge empty interiors, and this Van Hool when empty is lighter than the TerraLiner, just 19.7 tons. But also observe that when fully loaded with passengers, it weighs 30 tons. It's a long articulated bus after all, so those passengers will be spread out over its full 18m length. Note that all of the 18m articulated buses used in Milan are similar. They all weigh 19 - 20 tons when unloaded, and around 30 tons when loaded; they all carry between 130 to 156 passengers when fully loaded (ergo, the addition of 10 tons of weight); and the more recent ones all have electric motors that add up to 240 - 260 KW -- see http://www.trolley-project.eu/filea...lleybuses_-_Main_Features_and_Experiences.pdf . So as luck would have it, these 18 m articulated electric trolley buses currently operating in Milan are pretty much the same length and weight as the TerraLiner + Trailer.

Which makes me wonder: is 420 KW for the electric motors excessive? If the 18 m buses operating in Milan can make do with 240 KW, then does the TerraLiner really need 420 KW? However, in the case of the TerraLiner, there is bad-road and off-road driving to consider, the TerraLiner's comparatively huge wheels, and the challenge of climbing 5 % or even 15 % inclines. Furthermore, the 18 m articulated electric trolley buses that IVECO currently makes will use 4 motors rated at 80 KW each, providing a 320 KW of power in total. 320 KW is much closer to 420 KW. So I am simply citing such examples of real-world electric implementations as question marks, and possible points of reference for future discussion.

The more general point is that it would be a mistake to think that no precedents exist for the TerraLiner's drive-train, and that we are just taking a wild shot in the dark here. Articulated electric trolley buses provide a very useful precedent, and no doubt once I research MAN's "Lion City" 18 m articulated hybrid diesel-electric buses in detail, and an equivalent 18 m articulated bus made by Volvo, such "real world" exemplars will provide additional data worth considering -- see http://news.volvogroup.com/2013/04/23/volvo-to-introduce-hybrid-articulated-buses/. Newell motorhomes look more like buses than trucks, and the TerraLiner will be half-way in-between, with the camper body of a motorhome, and the base chassis and wheels of an occasionally-off-road capable construction truck. So it's anyone's guess what should be the most telling design precedent here, a hybrid bus, or a hybrid truck?

Let's stick with the 420 KW figure for six electric motors for now, as a kind of "provisional", reasonably justifiable ball-park estimate. If the above reasoning is sound, then this amount of power in the electric motors would give us a very nice, comparatively "zippy" sort of TerraLiner, equivalent to a truck equipped with an 800 HP diesel engine. Agreed, as campo so definitely pointed out, the TerraLiner won't be a sports car, but it won't be the slowest truck climbing the mountain either.


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9. A Real-World Example of an Extended Incline: the I-80 East from Sacramento to Lake Tahoe


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When it comes to inclines and their duration, let's begin with some "worst case" scenarios. As already mentioned, my own personal worst experience of an extended incline was driving from Sacramento to Lake Tahoe, on the I-80, segments 11 to 15 specifically, i.e. the segments that cross the Sierra Nevada -- see https://en.wikipedia.org/wiki/Interstate_80_in_California , https://en.wikipedia.org/wiki/Interstate_80_in_California , and http://www.wikiwand.com/en/Interstate_80_in_California :






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biotect

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614-0829.jpg 20110115-img_b8591-e1414141415882.jpg
DonnerLakeWide.jpg ltan-0266-12x18-300.jpg

Untitled-1.jpg tcr80b.jpg
tcr80c.jpg tcr80d.jpg



I think it was section 11 that destroyed my transmission, driving up from Applegate (elevation 611 m) to Blue Canyon (about 5200 feet, or 1,600 ) -- see https://en.wikipedia.org/wiki/Applegate,_California and http://donsnotes.com/tahoe/i80-sn.html :




i80-elevb.jpg



But as the above elevation cross-section indicates, there's a continuous climb all the way from Auburn to Donner Summit, taking one from 374 m to 2,151 m over the course of 60 miles, or 96.6 km -- see https://en.wikipedia.org/wiki/Auburn,_California , https://en.wikipedia.org/wiki/Donner_Pass , and https://www.google.com/maps/d/viewer?mid=zAw3KsgmRPlc.kw6WrICbdtYk&hl=en_US . The vertical rise is 1,777 m, a bit short of 2 km, and so the grade overall would be just 1.8 %, and nothing close to 5 %.

And yet I've driven all over Switzerland, and have never encountered a long uphill climb on a major highway in Switzerland as severe as this stretch on the I-80. The Swiss are fond of tunneling, and the Alps are dramatic glaciated mountains that soar high, but that have relatively low-elevatoin, flat-bottomed valleys. So somehow the Swiss seem able to keep their major highways feeling fairly "flat". As such, the I-80 up to Lake Tahoe is my best personal example of a long-duration up-hill climb. And as the image immediately above indicates, in some portions the grade is much steeper than 1.8 %, for instance, between Dutch Flat and Blue Canyon.

This is the kind of real-world example that interests me, and if anyone wants to post much more difficult examples, with worse gradients and longer climbs, please do!!

Iain
: as former highway engineer, perhaps you might still have access to a database of "World's worst major highway ascents for trucks", highways that have truly demanding grades of 4 or 5 % running for an hour or more? If you do, would you be wiling to suggest a few, for further investigation?

It's easy to imagine roads running from the Pacific coast up to the Andes, or from the the Ganges and Indus plains up to the Himalayas, that would have steeper grades and more extended ascents, perhaps running as long as 2- 3 hours. For instance, in a future post I'd like to examine the Friendship highway that runs from Kathmandu up to China, and so too, the Karakoram highway that runs from Islamabad to China. Islamabad is fairly low-lying, at just 500 m, and the Karakoram highway reaches 4,693 m, or 15,397 feet at the Khunjerab pass -- see https://en.wikipedia.org/wiki/Karakoram_Highway and https://en.wikipedia.org/wiki/Khunjerab_Pass :



KKH.jpg



So the Karakoram Highway might prove the most telling "test case" one could imagine. In the meantime, I'll start with California's I-80, a road that I know well.


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biotect

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10. Iain's Formulas Applied to a Real-World Test Case


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Using your formulas, Iain, I've tried to calculate the power requirement of this portion of the I-80 as follows:


(A) Froll = cr m g

cr = coefficient of rolling resistance. Rolling resistance can vary a lot, and this seems to depend significantly on tires -- see page 14, at http://ec.europa.eu/transport/modes/road/events/doc/2009_06_24/2009_gigaliners_workshop_jrc_2.pdf . I used the following table and articles to assume a coefficient of rolling resistance of 0.8 %, or 0.008 -- see http://www.engineeringtoolbox.com/rolling-friction-resistance-d_1303.html , https://www.physicsforums.com/threads/rolling-resistance-for-large-trucks.603149/ , and https://www.physicsforums.com/threads/rolling-resistance-for-large-trucks.603149/:



Untitled.jpg



m = the total mass of the TerraLiner + trailer, or 32,000 kg
g = 9.81 meters/seconds[SUP]2 [/SUP]


Froll = 0.008 x 32,000 x 9.81 m/s[SUP]2 [/SUP]= 2,511.36 kg m/s[SUP]2 [/SUP]



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(B) Fslope = s m g

s = upward slope: 1.8 % = 0.018)
m = total mass of truck and trailer = 32,000 kg
g = 9.81 meters/seconds[SUP]2[/SUP]

Fslope = 0.018 x 32,000 kg x 9.81 m/s[SUP]2 [/SUP]= 5650.56 kg m/s[SUP]2 [/SUP]



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(C) Fair= (r cd A v (speed + headwind wind)**2 )/2

r = 1.29 kg/m³, the the density of air at sea level, less as you get higher, but we will start at the climb at 374 m, so we'll work this figure throughout

cd = 0.85, the drag coefficient - typical truck/trailer is 0.96, a more streamlined bus is around 0.8, so I used .85 just to be conservative. But note that on one web-forum, a participant assumes a drag coefficient as good as 0.7 -- see https://www.physicsforums.com/threads/rolling-resistance-for-large-trucks.603149/ .

A = 10.2 m[SUP]2 [/SUP], the projected frontal area. I just used the width x height, assuming that the TerraLiner will be 4 m tall x 2.55 m wide

v air = either 19 m/s, or 30 m/s, this is the total of speed + any headwinds in m/s. I decided to do two calculations for two scenarios, one in which the TerraLiner takes on this slope at 50 kph, and the second at 90 kph. In the first 50 kph = 13.9 m/s, to which I added a moderate headwind of 18 kph, or 5 m/s, to arrive at 19 m/s.


So if I am interpreting your symbols correctly, I should insert numbers as follows:


Fair= (1.29 kg/m³ x0.85 x10.2 m[SUP]2[/SUP] x (19 m/s)[SUP]2[/SUP] )/2 = 4,037.53 kg m/s[SUP]2 [/SUP]divided by 2 = 2018.77 kg m/s[SUP]2 [/SUP]


I am not sure what you meant by **2, and I am just guessing here, that you intended it to mean raised to the power of 2. This has the virtuous consequence of canceling out the units, such that we again end up with kg m/s[SUP]2[/SUP]. I've taken first-year college-level physics, and got an "A" in the course, but it's been a while, and both my math and my physics are a bit rusty.

I wonder why we have to divide by 2 at the end?


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biotect

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11. The power figures that I get are much lower.....


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Now you stated that the total force to drive around is Ftotal = Froll + Fslope + Faccel + Fair . I can understand Fslope and Fair getting added to Fslope, but why Faccel? If you add in Faccel for a the duration of a given length of journey, then it seems that you are supposing that the vehicle will accelerate the whole way. Although of course the vehicle will accelerate and decelerate, it will have regenerative braking, so presumably this should help, a lot. In short, adding in acceleration just didn't seem right, and so I left it out. But no doubt I am missing something here?

Adding the above figures, and leaving out Faccel, we get 10,180.96 kg m/s[SUP]2 [/SUP]. Using one of the handy convertor websites now available on the web, this converts to 133.89 HP, or 99.84 KW, to climb this slope at 50 kph -- see http://www.convertunits.com/from/kg-m/s/to/kilowatt . Note that I've assumed an artificial 100 % efficiency for a drive-train consisting of electric hub motors, so there is no "h" value to consider. In other words, no 30 % transmission loss.

If instead we suppose climbing at 90 km/h, with a 5 m/s head-wind, then 25 m/s + 5 m/s = 30 m/s. Plugging that into the formula for Fair, we get 10,065.87 kg m/s[SUP]2[/SUP], and dividing this by 2, we get 5032.94 kg m/s[SUP]2 [/SUP]. Our Ftotal becomes 13,194.86 kg m/s[SUP]2 [/SUP], or 129.49 KW.

Now needless to say, a figure of 130 KW is substantially different from a figure of 450 KW!! And here I have calculated for a TerraLiner + TOAD Trailer weighing 32 tons, albeit for a slope of 1.8 %, and not 5 %. As you suggested above, 5 % at 100 kph for an hour really is extreme, although perhaps not inconceivable on a long road in the mountains somewhere. You are the expert in highway engineering, not me! But even if we plug in a slope of 3.5 %, Fslope becomes 10,987.2 kg m/s[SUP]2 [/SUP], Ftotal becomes 18,531.5 kg m/s[SUP]2 [/SUP], which translates as 181.73 KW, again over the course of a drive that would take about an hour. That's still a great deal less than 450 KW.

I then also wonder how you arrived even at your revised figure of 248 KW just to run flat at 100 kph, with no headwind, as stated in post #1965, at http://www.expeditionportal.com/for...igid-Torsion-Free-Frame?p=1962943#post1962943 ? If running flat, then slope is zero, so Fslope will be zero. If there's no headwind, then Fair will be based on 100 kph or 27.78 m/s, so 8,631.24 kg m/s[SUP]2[/SUP], divided by 2, and we get 4,315.62 kg m/s[SUP]2[/SUP]. So just adding Froll + Fair, we get Ftotal = 12,946.86 4,315.62 kg m/s[SUP]2[/SUP], which translates as 126.96 KW. Which again is quite a bit less than 248 KW. It's also less than your most recent revised estimate, in response to campo's post. Compare:


I reran the spreadsheet, with the figures given. 2.5m x 4m, and 24ton for the Terraliner. In the previous calc I did not take into account the TOAD.....

Allowing for the 30% transmission losses as previously, you still need 248kW on a flat road with no headwind @100kph.

From my driving experience I think that I can maintain on the flat a modern truck combination of 30 tons at speed 90km/h with something between 200 to 250 hp. I did never measure it.

Just ran the numbers, and you are spot on, the formulae come up with 154kW (206hp) to run a 30 ton modern truck (Cd 0.08) on a flat road with no headwind :)


In the first calculation quoted, presumably you were thinking in terms of 24 tons + 8 tons for the trailer, so 32 tons? Which is not so much different than the 30 ton truck in the calculation that you then did again after campo posted. So I guess I am puzzled not just about the difference between your numbers and mine, but also why your two calculations were so different, and why your run-flat-estimate at 100 kph, no head-wind, for a 30 - 32 ton truck, dropped from 248 KW to 154 KW....:costumed-smiley-007

No doubt I am also doing something wrong, or failing to take something into account, and it would be good to know what that is.....:)


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biotect

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12. Why is it necessary to include Faccel?


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In sum, Iain, before I move on to calculations for more demanding inclines like the Karakoram highway, it would be great if you might look over the above, and tell me where you think I went wrong. Or, where your assumptions were different from mine, and why mine are not justified. This is getting very technical, but as I said above, before we start quoting the figures that you arrived at as holy writ, I want all assumptions to be as clear as possible, and exposed to the full light of day. I did not include Faccel, and this might have been a mistake. But I guess I need to know why I should include it, because acceleration requires energy that simply maintaining a constant velocity on a flat surface does not.

If a vehicle were driving along a completely flat road with zero slope, and if there was no air resistance because it was driving through a vacuum, and if had an extremely low coefficient of rolling resistance, then once accelerated to a certain velocity, its tendency would be to want to go on forever at that velocity. Gradually the rolling resistance and/or any other kinds of friction would slow it down, but only very gradually. This is why it's so difficult for trains to slow down: they are huge linear masses running on metal wheel/rail combinations that have very low rolling resistance coefficients, and they present a very small "face" to the wind, given their total length and mass. Once all of that mass has been accelerated, it wants to go on almost forever. It's just basic physics. Analogously, when a truck is driving on flat ground, after it has accelerated to its desired constant speed its weight becomes more or less irrelevant, and the only further energy required is energy to overcome wind resistance, and rolling resistance.

Driving up a slope is a bit different, because technically speaking, driving up a slope at a constant velocity is a kind of acceleration, relative to earth's gravitational center. But presumably that's where Fslope comes in, and all of this should be captured by Fslope.

Once more, my math and my physics are rusty, so if I have made mistakes in any of the above, I really would appreciate it if you were to dissect those mistakes in detail. Please feel free to apply a surgical scalpel to what I've just written, because I do want to get clear about where and how one should apply such formulas; and why; and what reasonable figures one can use as assumptions. But I realize that there is a great deal to absorb in the above. So don't feel rushed, and only respond when you can....:) ...

Again, it has a been a real blast corresponding with you, because you are willing to consider the TerraLiner on its own terms, and work within the parameters of the stated "design brief." :luxhello:... Although the Terraliner will definitely be a design-driven vehicle, and design considerations will come first (which include operational or "logistical" considerations, such as glamping for 3 months on the Namibian coast...), I've been itching for a while to make further headway vis-a-vis how a hybrid drivetrain could be implemented. And that has to start with reasonable and accurate power calculations.

All best wishes,



Biotect
 
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Iain_U1250

Explorer
If you do a Google search for "Wind Resistance Power Requirements" you get loads of pages with the same formulae. I used to work in a research organisation, did a lot of research on rolling resistance of tyres, and had colleagues who did wind resistance tests in wind tunnels. I have tried to work them out from first principles, but feel free to have a go, if you enjoy the maths :) These are the simplified formulae, but accurate enough for these purposes, computer models for how tyres change with increasing rotational speed, and how the drag coefficient can change through micro vortices being created at higher speeds etc.

I don't have much time this morning, so answers will be short :)

30 tons - 22 ton truck + 8 ton trailer. Although with the amount of equipment on Terraliner, keeping it lightweight is going to be a real challenge.

Numbers are different because you forgot the last bit of the equation to calculate power:
The total power required for each different scenarios is:

P = Ftotal v/h where , v : velocity in m/s and h : drivetrain efficiency, which depends on the configuration.




In Campos example, he asked for power at 90kph. The power requirements at 90kph are a lot less than at 100kph, due to the it being proportional to velocity to the 3rd power for wind resistance.



Faccel is a tricky one, it is the one that most people associate with "Performance" Acceleration at lower speeds will good, is it will use all the power that later on get used to overcome the wind resistance. For a fixed amount of power, Terraliner will accelerate up to the point where there is no power left for acceleration, and that is your "maximum speed" Light weight, little cars accelerate quite fast with little power up to around 50kph, then wind resistance starts to take over and then they slow down.

I have no idea what the drivetrain efficiency of an hub motor is, but doubt it will be "1" - Terraliner needs motors that will go from 0-120kph? With a 14.00 R20 tyre, that means

Tire Diameter 52.0"
Circumference 4148mm
Revolutions 241/km

So at 120kph, the tyre is only doing 482 rpm. So you will need a reduction hub, as electric motors don't like being that slow and the power efficiency of a motor is around 95%, so maybe 10% less for efficiency in a hub drive system. Maximum speed big electric motors is around 3000rpm, so to probably need a 6:1 reduction hub. I'm sure there is info about this somewhere on the net. Realistically, hub drive in a 6x6 configuration is not going to happen, too much R&D, most likely is a standard transmission being replace with an electric motor and reduction gearing. The diffs and transfer case remain conventional. So efficiency around 20%??

Another thing to take into account when driving around in a truck, a 5% downhill grade means you have double the power pushing you down the hill than the power required to overcome wind resistance and rolling resistance combined, which means you are going to accelerate rapidly until Fwind+Froll = Fslope. A quick check on the spreadsheet says this happen around 170kph for Terraliner, but most likely your tyres have self destructed before that and you are a smoking wreck at some corner. That's why trucks slow down by using lower gears to decrease drivetrain efficiency as much as possible, and try turn the engine into an air compressor using the exhaust brake. You can't dissipate 400kW of power using the trucks brakes, way too much heat, but the engine and transmission are designed for that amount of power in a truck. Terraliner will need some sort of a load bank to dissipate the heat, just another thing to fit into the chassis - a 200kW like this maybe Load Bank
Another 1m3 of space taken up. A very steep grade - 10% will require a lot more load to be taken up, so maybe a 400kW or even a 600kW load bank, - 2m3 and about a ton. These are things that a trolley bus will not be designed for, and don't think you can make the generators reverse into loads either.

In Terrliner's case, recursive braking using the motors to charge the batteries will help braking efficiency, but I don't think a smaller batteries can handle the full 400kW that the motors might be trying to dissipate, and what happens when the battery is full at the top of the hill. There needs to be a way to shed the extra power as heat by decreasing drivetrain efficiency like in a normal truck. Not sure how this can be done - the power has to go somewhere if not into the batteries.
 
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biotect

Designer
Hi Iain,

Just briefly, I didn't forget "h", I deliberately eliminated it, because I thought it would not apply to electric hub motors that have no intervening transmission. See post #1992 above, second paragraph:



Note that I've assumed an artificial 100 % efficiency for a drive-train consisting of electric hub motors, so there is no "h" value to consider. In other words, no 30 % transmission loss.


I was puzzled by the fact that you kept deducting 30 % for the transmission, when what we're discussing is an electric vehicle, where at best there might be cross-axle transmissions in a three-motor configuration. As Haf-E suggested, the energy loss for these transmissions would be much less in comparison to a standard sort of truck transmission. But in a six-motor configuration with hub motors, why attach any value for "h"? The only reason might be that even hub motors will still need a simple gearbox so that they can drive at very low speeds. But again, the efficiency loss for hub motors would be even more minimal. I'm not sure what it would be, but surely not 30 %, as you have been calculating?

Or am I missing something else? Did you mean something else when you suggested that I "forgot" the last part of the equation for power?


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Extremely interesting point about how trucks use their transmissions to negotiate descents. I learnt to do the same with my car when living in Switzerland. In the Alps brake pads will disappear in no time if one constantly relies on the brakes, instead of using the transmission to slow a vehicle down when descending. There are horror stories in the Alps of tourists having relied so much on their brakes during a vacation, that suddenly their brakes disappear on a descent, they are too startled to think to use the hand brake, and they fly off a cliff.

In short, I fully understand how "transmission inefficiency" can prove a very good thing on descents, and I am long practiced at "transmission braking", or what is commonly called "engine braking". You've posed a problem that certainly has me perplexed, and I wonder what the solution might be, in a hybrid vehicle with electric hub motors?

Here it would be interesting to find out how Oshkosh has its A3 diesel-electric HEMTT handle the problem. The HEMTT is a very big truck, an 8x8, and it's in a completely different size-class than the relatively light 4x4 discussed in the video that you posted. See http://oshkoshdefense.com/vehicles/hemtt-a3-diesel-electric/ and http://oshkoshdefense.com/wp-content/uploads/2013/08/HEMTT_A3_SS_6-13-11.pdf . The A3 HEMTT's curb weight unloaded is about 16 tons, and loaded it's 32 tons. It's also rated to pull a trailer, such that the combined total weight of a loaded A3 and loaded trailer would be 47 tons. So for the A3 to descend a long slope with a trailer in tow, would require dealing with a great deal of weight, and hence, dealing with a great deal of energy to dissipate, as you so eloquently put things. But once again, the A3 HEMMT is most definitely a diesel-electric vehicle with 4 electric motors, powering 4 axles. The cross-axle transmissions surely could not prove sufficient to do the kind of energy dissipation that you've described as necessary? Or could they?

The A3 HEMTT has air-brakes, but that alone won't solve the problem -- see https://en.wikipedia.org/wiki/Air_brake_(road_vehicle) . So I wonder how it does solve the problem?

As you suggest in your post, one obvious solution might be transferring the energy via regenerative braking. There's research to suggest that on steep hills hybrid buses need to use their brakes much less often than conventional diesel buses, because of regenerative braking -- see for instance section 3.5 in http://road-transport-technology.or...Technology and Feasibility Study - Patten.pdf. But an urban transit bus descending a steep hill in a city, is not even remotely comparable to a heavy truck negotiating a one or two hour continuous descent in the mountains.

The first thing that occurs to me, is to say that prior to initiating a descent, the TerraLiner would probably want to ensure that it's battery banks are thoroughly drained. When descending the electric motors would then function as generators, and perhaps that might slow things down a bit. Once the batteries are full, the TerraLiner would have to stop, and that might be a good time to run all electrical systems at full tilt to drain down the battery banks again, doing all the washing, running the watermaker, etc. This may seem silly, but I've seen large trucks trying to negotiate descents that also have to pull over for a while, to dissipate thermal energy.

Indeed, braking on descents with conventional trucks is a big enough problem, that on particularly steep grades in the Alps and the Rockies there will be "runaway truck ramps" -- see https://en.wikipedia.org/wiki/Runaway_truck_ramp , http://www.crashforensics.com/mountaingradecrashes.cfm , and http://www.usroads.com/journals/rej/9708/re970801.htm , http://www.caranddriver.com/features/runaway-truck-ramps-explained-feature , https://nevadadot.com/Traveler_Info/Safety/Truck_Escape_Ramps.aspx , https://nevadadot.com/uploadedFiles/NDOT/Traveler_Info/Safety/Truck Escape Ramp Brochure.pdf , and https://www.youtube.com/watch?v=21vO8zlGAcM , https://www.youtube.com/watch?v=pjjl4KkVjSo , https://www.youtube.com/watch?v=mzEckdEW0Ak , https://www.youtube.com/watch?v=h-VbZb3q_T8 , https://www.youtube.com/watch?v=TQcDgkbAi30 , https://www.youtube.com/watch?v=14bZx3Jcu20 , and https://www.youtube.com/watch?v=E2xw5uD_kcM :






There is even a dedicated YouTube channel called "RunawayTruckRamp" at https://www.youtube.com/channel/UCxtmF9Zewf4WhKWfPwHAEIw . So it would be inaccurate to say that traditional diesel trucks have completely solved the problem of negotiating steep descents.


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Here's a thought. Because "engine braking" and so too "jake braking" (what you described, using the engine as an air compressor -- see https://en.wikipedia.org/wiki/Compression_release_engine_brake) sometimes still proves insufficient, MAN and others will fit trucks with supplementary "retarders" -- see https://en.wikipedia.org/wiki/Retarder_(mechanical_engineering) , https://de.wikipedia.org/wiki/Retarder , https://translate.google.co.uk/translate?hl=en&sl=de&tl=en&u=https://de.wikipedia.org/wiki/Retarder , and http://www.voith.com/en/products-services/power-transmission/retarders-bus-2689.html :



[video=youtube;aDejo3dXEP8]https://www.youtube.com/watch?v=aDejo3dXEP8 [/video]
[video=youtube;EKa97RYxE_Q]https://www.youtube.com/watch?v=EKa97RYxE_Q [/video]


These videos describe different kinds of retarder technologies, but the one that interests me the most is the first, Telma's "frictionless" electro-magnetic retarder. Here electricity is used (not produced) to slow down a rotor on a drive shaft. Because this system is completely electro-magnetic, it can be turned off, and won't affect the efficiency of the drive-train when the vehicle runs flat, or climbs a slope. It only introduces inefficiency discreetly, precisely when it is wanted and needed. It may seem strange, to be sure: the electric motor would be acting as a generator, producing electricity that would be partly consumed by a retarder immediately adjacent on its drive-shaft, a retarder that would be trying to slow it down. But once one enters the world of truck braking technologies that try to address the conundrum you so deftly described, things do get surreal.

One could then imagine three such retarders (they are not that large), fitted to three drive-shafts connected to three electric motors. Which would then be a good argument for three electric motors driving three cross-axle transmissions, instead of having six hub motors.


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Anyway, that's just one possible solution, off the top of my head.

In sum, an excellent point, it has me puzzled and intrigued, and if anyone wants to suggest more solutions, or elaborate upon and/or criticize what I just proposed, please post!

All best,




Biotect
 
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Iain_U1250

Explorer
We just need to keep in mind the principle of conservation of energy. As a closed system, all the energy needed for Terraliner has to come from somewhere, and any excess has to go somewhere. ? A resistive load bank coupled with an air cooler ( or using the gensets radiators) could be used for dumping the power ( heat) not used.

One of those retarders will be easy to fit if you were using a single electric motor, all sorts of problems with individual hub motors, if one is slightly more efficient than the other , the truck will change lanes by itself. It will take a sort of ABS computer to keep control of this type of thing. Imagine the amount of R&D that has gone into just that system, many $millions. R&D time would be 4-5 years, from concept, prototype, testing, certification in each market to their design rules, to finally commercial launch and integration into the existing product line.


I check my spreadsheet, it seems OK, Maybe if you put together a more formal spreadsheet for everyone to use. Where each variable is visible and can be changed. I can reduce the drivetrain efficiency factor to 20% loss, but it will never be 0% due to the fact you will need hub reduction gearing as a minimum, so 10% at best.

Back to the basic question: Will a diesel-electric hybrid be more reliable and fuel efficient as the modern common rail diesel engine. Modern truck run 1,000,000km as a norm. Who knows how reliable a diesel-electric hybrid will be, the more things you add, the more things can go wrong. Cutting edge development is very expensive, and there have be so many spectacular failures in technology, the 5 years between prototype and commercial product means a lot can change and render some developments obsolete.

Maybe a Toyota Prius style system, with both an electric motor and diesel being connected to the transmission, and using the motor for regenerative braking and the motor to charge up a fairly large battery bank for "stealth mode" driving, and adding the power of the electric motor for driving up steep hills when required.

I think Terraliner needs to stick with fully developed and tested commercially available systems, not a cutting edge system. The only real engineering should be the packaging of those systems into the truck. If Iveco / MAN / Oshkosh have suitable rigid 6x6 chassis with diesel electric drivetrain available, you need to choose one of them, and package it around that. The Terraliner prototype will need at least a year and 100,000km of testing of the integration of the various system before it could be commercially released, you don't want to add another 5 years of developing and testing unique drive trains.
 

biotect

Designer
Iain,

Once more, we are on exactly the same page, regarding the question of practical build-ability:


I think Terraliner needs to stick with fully developed and tested commercially available systems, not a cutting edge system. The only real engineering should be the packaging of those systems into the truck. If Iveco / MAN / Oshkosh have suitable rigid 6x6 chassis with diesel electric drivetrain available, you need to choose one of them, and package it around that. The Terraliner prototype will need at least a year and 100,000km of testing of the integration of the various system before it could be commercially released, you don't want to add another 5 years of developing and testing unique drive trains.


As you suggest in this quote, these companies will not have their diesel-electric drivetrains already combined with their rigid ladder-frame truck chassis. In other words, as near as I can tell neither MAN nor IVECO-Astra have yet made a marriage between their truck divisions, and the serial-hybrid technologies that they've been developing in their bus divisions. They've developed full "packages" of commercially available diesel-electric drivetrains to be sure, but have not yet put them into a vehicle of the kind that I am describing. That's the innovative part: taking the know-how of MAN's bus division, for instance, and transferring that to create a drive-train for a rigid 6x6 chassis that otherwise resembles a SX-44. Or taking the know-how of IVECO's electric trolley division, and transferring that to create a drive-train for an IVECO-Astra 6x6 truck.

In the case of Oshkosh, I don't think they "do" rigid frames. The MTVR frame is most certainly not rigid. Oshkosh's "Pierce" firetruck division has developed a commercial spin-off of the MTVR, in the form of an off-road fire-fighting truck called the "Hawk Extreme Wildlands Tanker" -- see http://www.piercemfg.com/getmedia/8...4bd0d4/15549_HawkEX_sellsheet_lowres.pdf.aspx , http://www.fireapparatusmagazine.co...-firefighters-into-out-of-the-way-places.html , and see post #330 at http://www.expeditionportal.com/for...igid-Torsion-Free-Frame?p=1604501#post1604501 :



15549_HawkEX_sellsheet_lowres1.jpg 15549_HawkEX_sellsheet_lowres2.jpg



As the video still available on YouTube makes clear, this has a frame that can flex:






Furthermore, I don't think that Oshkosh has any genuine experience with true serial-hybrid drivetrains. Their ProPulse system only uses super-capacitors to store energy temporarily (a few minutes), but otherwise, they advertise ProPulse as a "pure diesel electric solution" with "no energy storage". This kind of vehicle is attractive to the military because it simultaneously functions as a big electric power generator when stationary. So an A3 HEMTT can transport a payload to a temporary airfield, and once there, it can plug in and literally light up the whole airfield, too. There's no need to pull a generator on a separate trailer, because the A3 is the generator. By way of contrast, both MAN and IVECO have plenty of experience creating true serial-hybrid vehicles with substantial battery packs.

So agreed, the "novel" part should be the packaging of a commercially available serial-hybrid system into a truck; the drivetrain itself should not be radically innovative. And once more, the idea of a parallel hybrid system as per the Toyota Prius is still on the cards. MAN has developed a parallel hybrid system for its TGX line of trucks. But another reason I favor full serial hybrid, is that this then gives me tremendous design flexibility when locating the ICE motors that power the generators. Jenoptik generators can go on the sides of the vehicle on slide-out trays, whereas in a parallel hybrid configuration, I would have to put the diesel motor either on the front or the back of the vehicle. But I hear you regarding the reliability issue.

Interesting that you seemed to accept the idea of electro-magnetic retarders as a possible solution to the braking problem for extended descents. Note however that a single drive-shaft would defeat one of the design objectives of serial hybrid, namely, building in fail-safe redundancy by having multiple electric motors. But as I said, these retarders are not huge, and three of them could be fitted to three drive shafts attached to three electric motors. This probably would mean adding something to the MAN or IVECO serial-hybrid drivetrains that they currently do not have. I am guessing here, but I suspect that MAN's "Lion City" hybrid transit buses, and IVECO's electric bus-trolleys, will use a combination of ordinary "service" brakes along with regenerative braking to slow down the vehicle. They probably do not have electro-magnetic retarders, because they are not intended as inter-city transports that would need to negotiate long descents. But inserting an electro-magnetic retarder into a driveshaft does not seem like an especially complicated add-on.

The only question would be whether it would work: whether three electro-magnetic retarders could provide enough additional braking "friction" (if one can call it that, in a frictionless system!), to slow down a 30 ton TerraLiner + Trailer descending continuously for an hour or more, such that the service brakes would only need to be used sparingly.

In any case, interesting stuff. As I wrote above, I'd like to wait with the calculation for "h" in a 3-motor serial hybrid configuration until I hear from a few others, for instance, Haf-E, regarding what the efficiency loss might be for three cross-axle transmissions. It will most certainly be less than 30 %, but granted, it won't be 0 %. So we'll have to put off crunching numbers until that becomes clear.

In the meantime, it would be great if you might be willing to suggest any other long, challenging descents with steep gradients!

All best wishes,


Biotect
 
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