Hey dwh,
1st let me state: I am NOT a e-drive specialist!! I DID know about different kinds of motors and generators and how they can be controlled - but that is a a few days going through Google and wikipedia and specialist websites - ...don't want to bother with that at this time. What I "know" about hybrid tech is mostly what I stumble upon when reading up articles about it!
THAT is also why I might change my mind about hub-motors. (If you want to bother....)....go back a load of pages and see me "fight" hub-motors.
Then hub-motors were huge, super-heavy, slow-running (direct drive) pancake units that are basically inside the wheel (rim/tire). Then I stumbled over the article of the Swiss/Dutch team with their e-racers - 37KW "fast runner" with planetary reduction, super-LIGHT weight .....now hub-motors don't look so bad anymore to me!! The wet-argument is not an argument for me - nothing easier than waterproofing a e-motor. Vibration and impact shocks are the only thing that tries to keep me off hub-motors, though I argued that one already too.
I DID drive trucks (40-tons to 84 tons) throughout Europe crossing the Alps about 1-2 times per week. That was for about 4 years on-off between 1989 and 1994. I "caught" the mandatory "enforced" speed-limiter (the sucker actually pushes the accel-pedal OUT when you approach the adjusted speed limit - 85km/h adjusted, legal 80km/h. Speeding was only possible downhill, when it was steep enough...) which required a change of technique when approaching a hill....(Luckily I missed the change from tacho-disks to blackboxes....)
Yes, but won't *need* full torque at cruising speed. So you size the motor to get the truck moving and up to cruising speed, and use a gear reduction for low-crawling. That way you can use a smaller motor, optimized in size for "high range", which is what the truck will be doing 90% of the time, and gear reduction for "low range".
Ideally the ONLY gear/trans involved should be a reduction-gear directly on the motor and or on the differential, IF you go with central motors.
I am pretty sure you that motors exist, that dish out "axle-snapping" torque at super-slow rpm and on the other hand can run high enough to bust high speed limits. If you have a good motor with field-control you can actually use it (in generator mode) to get to a stand-still!!
Even in super-slow and difficult terrain.
[Today's hybrids are not much off re-generators. If you are little ingenious/inventive you actually can cajole the CU into applying a lot more braking action to the re-gen system than they do from the factory - sample somewhere on
http://origin.autospeed.com/....]
Ah. Perfect place for a torque converter.
IF I am not wrong the MAN/KAT torque converter is a hydraulic unit. So every time you need it, you convert a load of energy into heat.
WHY would you want that if you can just control via the e-motors?
Not at all. *Where* you bleed off the momentum doesn't matter - at the wheel, at the axle, or between the motor and transaxle. Doing it ahead of the transaxle is the same as using an engine brake on a diesel - let off the "go pedal" and braking action starts. Because it's electric, you need to manage your use of the pedal because it doesn't really "coast". If more braking is needed, then you push the "stop pedal", which can be setup either for just the mechanical brakes, or can be a complicated management system which maximizes the regen before engaging the mechanicals.
Okay - I think people are still stuck with comparing the hybrid re-gen thing with the older auxiliary braking systems -
Jake-brake (I never encountered one in Europe, but would like to shoot every trucker using it in Panama!! Everyone here thinks taking out the muffler makes it work better.....and they certainly use it to a near standstill.....),
Electric/magnetic brake (TELMA and others, manual says you must not use them for the 6 min before a intended stop - or might burn! Bad news if you HAVE to stop earlier!! The things go glowing yellow-hot when braking - field controlled!!) or my favorite the Voith-Schneider
Hydraulic Retarder (ALWAYS works - no max time limit, just keep the engine-rpm up so the cooling water keeps circulating!! ....also excellent to warm up the engine on a cold day, if you cannot get to drive under power quickly....),
EXHAUST-brake (a "throttle" in the exhaust to choke the engine, at the time I was driving they were rather lousy - proper means of control was just about to come on the market to be able to completely choke without destroying the turbos....)
ALL of these systems are AUXILIARY systems!! ON a fairly fast and steep pass down hill it STILL required application of the friction brakes quite often (mostly braking into turns).....
However, it was possible to brake and let the brakes cool off again - with the AUX holding enough in the meanwhile....
Now - IF we go full serial hybrid, I would expect the re-gen braking go effectively to a near-standstill.
I would expect the electric part of the braking system to even HOLD in tough terrain (and only apply friction brakes after a certain time limit, e.g 4-5 sec. if the vehicle is not put in motion in the meantime - no doubt, holding under e-control WILL use up energy!!).
Also - I certainly would NOT use 2 brake pedals!! Way too confusing! IF you must have 2 separate brakes (which I do not advocate....), then keep the regular brake and use the e-brake with a lever on the steering column, like established for most aux-brakes.
[Exhaust brakes would have a floor-switch for the RIGHT foot (eliminating the chance to engage accel and brake at the same time - ....wouldn't be too nice for the engine! I understand the Jake had a separate control lever/buttons too....., but no pedals)
HOWEVER - I would push for a "transparent" single brake-pedal arrangement! In a "sophisticated" machine like the Terraliner you should not even feel WHAT brake is braking!! The friction brake should only be necessary as a parking brake (or the sample I mentioned above...) and be automatically applied slightly once every 3 days of driving to clean of rust!! It should be possible to reduce friction brake weight to less than 1/2 of present day usual truck brakes....
[OBVIOUSLY - they still need to be able to stop the whole truck and trailer on the steepest/fastest down hill run you possibly can find yourself in - at least once to a complete stop!! Just as a safety-anchor.... So, the brakes will still be of a good size!!
At the end, YES you WILL have to get a Terraliner license (or at least a thorough check-out, ESPECIALLY if you have zero "HEAVY"-experience!!) to be able to operate it safely...No matter if direct diesel drive or parallel or serial hybrid, you STILL have to be aware of how mass/inertia/braking limits need to work together!
[I saw plenty of burning or at least wasted brakes on the bottom of the Austrian side of the Brenner-Paß, where it joins the Inntal-Autobahn towards Germany. Mostly Dutch trucks with very young drivers! Mostly on their 1st solo Italy-run. They mostly passed everyone smartly on some of the straight downhill stretches, probably wondering why everyone was "semi-crawling" downhill!! A fast run would only be possible if you had an empty stretch back from the south. As soon as there is some cargo on the truck - you HAVE to make do with any and all brakes, BUT the friction ones!
One could smell them 10 min before seeing them!! Burned brakes have very distinct smell! .....am I right, OptimusPrime ?]
ON the Terraliner I would expect to also have a transparent accelerator - reaction just like with a "gas pedal" as we are used too!
[Never mind, that nowadays you are NOT stepping on the gas but on a potentiometer....]
Obviously, "coasting" would be electronically controlled. You even could get a custom "feel" built into the control-system!!
and YES you CAN coast on e-drive, involves shorting certain circuits and you become a "roller"....
[If that is practical for hybrid e-drive - I would not know...]
Brakes - same as Accel - you will "brake" on a poti too - when the friction brakes have to come in a electric air-valve will apply these instead of a mechanical air-valve (...now considering that the Terrraliner will be a ELECTRIC vehicle, one might want to analyze if a air-brake still holds enough advantage over a hydraulic one.... IF Air-SUSPENSION is chosen, air-BRAKES is a no-brainer.....).
WHICH brake is needed would be decided by the control unit! I just would want a visual indication when the friction brakes are on (yellow LED or so....) - I would expect to see that one only after a full stop, when the brakes engage as a parking brake or holding brake in terrain - yellow flashing when they are used when the vehicle is still in motion, THAT's when they get hot.
You mean "regen braking alone" ? 1]
No, it's probably not fine. You drive a truck right? 2]
I have a Class A commercial license (with HazMat) and you know as well as I do that there are a lot of dorks out there who think nothing of cutting off a 40t truck. THEY seem to have a lot of faith in the brakes on the big truck to save them from their own stupidity. They have more faith in the truck's brakes than *I* do.
So no, regen is not enough. I want bloody big friction brakes that I can jump on when needed.
1] Yes I do....
.....see above
2] Not anymore, but I did - up to some interesting weights! [I started to do some interesting
drifting, going on a juust wet - still slimy from all the dirt and not washed off from the rain yet - Autobahn through the rolling hills part from Munich to Salzburg, with a Heavy Loader - 500hp DAF tractor with heavy Tandem-drive axle and 5-axle Goldhofer-trailer (MGVW-95 tons). Rig was empty, brakes are super-sensitive as they are super-heavy-duty, but when the rig is empty they bite hard even if you juuuust touch the pedal. The rig had an empty-weight of 22+ tons!! Anyway, I just went over a hill top and back off the accelerator to not pass 90 km/h - tacho-disks!! ....engine was braking so good just by itself, that it actually slowed the tandem axles BELOW speed!! Next thing I have the trailer jack-knifing and drifting on the middle-lane, when I am on the right one!! A little trailer-"stretcher"-action and a small bit of accelerator brought it in nice and smoothly....never forget that one!! - ....which brings me to...]
....another recommendation, BIO: IF you provide a trailer-coupling, provide a "trailer-stretcher" too. I believe they are outlawed since a long time (trailer short haulers would cause accidents down the road by not braking properly, but abuse the stretcher to save their brakes on the truck but waste the ones on the trailer....), except for Heavy Load Special rigs.
Terraliner would qualify as a Special Rig. IF you wanted to tow a trailer with Terraliner you need to get a proper license anyway and a Owner of a Terraliner would not be prone to abuse his own trailer!!
However this item could save your day - if you ever get caught drifting around on a icy road in NE-Siberia! ....or just a regular cold winter ANYWHERE!
dwh - a properly configured electric brake (generator) would actually be a lot more trustworthy than any friction brake out there! And you can even make them with auto-field generation (kind of like the air-brake actuators on Truck rear-axles - if you loose brake-air, a set of springs will apply the brakes and stop you - ....and KEEP you locked stopped until you supply air again - fix that line or when getting towed, release them by compressing the spring with a bolt, that you screw in!) - in any case you have the friction brakes as a back up.....
I think, regarding driveline, brakes, driving we need to get a completely new set of impressions/ideas if we think Terraliner/Serial hybrid - Past Engine-direct drive experience will not apply to the extend we sometimes imagine right now....
....you know as well as I do that there are a lot of dorks out there who think nothing of cutting off a 40t truck.
Certainly do!! And didn't think of much cutting out in front of them dorks either, IF they were the kind that would come flying along at 240km/h flashing lights from 3 km behind, approaching a hill!! I figured if their high-beam flasher works that great, surely their brakes must too!!
I am not that provocative anymore today - besides most climbs are restricted nowadays - no more passing of trucks by trucks! But back then I would not trade a 5-10 min climb for a 30-45min climb behind a overloaded/under-powered Romanian Truck doing 3-5 km/h were I would do 85-90km/h!!
So - late, but: Apologies to all the Porsche/BMW/Audi Autobahn-racers I had test their High-beam/brake coordination skills!!
I think that's way over-estimating. 98% *may* be achievable when cruising, but not in traffic, twisty mountain roads or when low-crawling.
You can control to 100% - ABSOLUTELY!! Question is, if this is possible efficiently! (I would say today with computer controlled Thyristor systems it should not be a problem at all - BIO, THIS IS where we all would like to get some feedback from your e-drive specialist engineering friends!! btw - I never got an answer from the BOSCH folks regarding their parallel system ....)
Also, getting back to the bleeding off of momentum. If the truck is designed to run an engine/generator big enough to drive the truck without batteries, then the battery bank becomes minimized, and that reduces the storage space available for the bled off energy. This gets us back to having to provide a dump load.
So really, using a big engine/generator to electric motors at some point becomes pointless. You might as well just use a regular ol' diesel drive train and forget electric. I mean really - that Bosch system only achieves a SIX PERCENT efficiency increase? Yea, okay it's probably worth it for a fleet operator, but for a motorhome? Meh, not enough savings to bother, and while it might amortize on a fleet vehicle, it'll never pay for itself on a motorhome. (Though, using that generator/regen unit to add regen braking and battery charging to a normal truck might be a really nice feature for a motorhome.)
For hybrid, I think the key is making it essentially a battery powered vehicle, with on-board recharging ability. Then the battery bank has to be bigger, which is good for regen braking energy storage - and the engine/generator can be smaller, which is good for fuel consumption.
The key of course, is balancing the energy management properly - AND - running the generator to recharge batteries both when when the truck is being driven, AND when the truck is parked.
And that is EXACTLY what we all are talking about for ages!! :ylsmoke:
Now - for a mobile-home/Explorer/Overlander, serial hybrid JUUUUST MIGHT make sense, depending how much you really want to move - ...and how long you plan to stay in places....[besides that a serial hybrid is a must for the design goals....].
I can see that at the present diesel-gen-e-drive efficiency levels and present and near-future battery tech, Serial hybrid is NOT ready for the longhaul truck.
A Longhauler cannot afford to waist a lot of cargo weight on batteries. That's why I believe the Bosch System is not going to make it all the way through the Brenner Paß without falling back on a hydraulic retarder or at least some EXCELLENT exhaust brake. Then their system is just a start-up into the heavy Weight-Hybrid world. They can run for 6 km on battery only, which is great in inner-city stop-and-go and to maneuver around on a ramp or power a electric A/C for the driver when waiting on load in South Italy or Spain!!
Oshkosh shows, that Military may have other priorities than Long Haulers - after all Military Trucks are mostly parked somewhere, most of their live!
Instead of having to load and truck in a Stationary Power-plant, why not make the truck the power plant and drive it electrically, when the plant is NOT in use otherwise? Brilliant - hopefully!
Now where we get at with a electric Motor-home/Explorer/Overlander is, that IF we already use electricity as our means of powertrain, it should only make sense to optimize the whole rig to use electricity for everything possible: Lights, heat, cooling, cooking, slide-outs, raising-roofs, EVERYTHING possible.
Which - at least for me - implies that I would carry a SERIOUS battery bank!! YES - it will cause a serious chunk of the empty weight, but it also will allow me to maximize hybrid efficiency to the max.
As I mentioned before - hopefully the bank size can be proportioned to the longest, fastest, heaviest, steepest possible downhill run ANYWHERE!!
[NO idea which run that would be - BUT I am sure SOMEONE on Expedition Portal WILL know!!]
.....this way you would not have any need to burn energy to heat the environment! (Hopefully this would be enough to keep me "householding" in the worst possibly conditions - energy wise - for at least 24-36 hrs]
[I also would always have/maintain serious load of water available to heat up...and use later....]
Obviously for a Longhauler a huge battery bank is a no-no. For a MH/E/OL it is kind of part of the deal/equipment, might as well use it.....
.... Define "a lot". It's a bit like designing solar systems - one can get hung up worrying about a percent here or a percent there of efficiency losses, which in the big picture don't much matter anyway.
Depending on the trans and power you push through it - 15-45% loss - going up in heat!
What I proposed doesn't need any shifting implements either, unless you want to go into low range for crawling. Since it has that, might as well put the reverse there as well and not have to bother wiring up the motor (and regen system) for reverse.
MY mistake! I thought you wanted to keep the WHOLE TATRA drivetrain incl. trans and transfer......
I think, unless Terralainer goes with heavy, slow-speed, pancake - "in wheel" - hub-drives, there is no way around "some" gears in the system...
[Again - that's where Bio's engineering friends need to consult their sliderulers.....]
Wiring up e-drive for backwards running is hardly an obstacle -even if you use AC.....IF I can save the Trans (and hopefully Transfer as well), I gladly would wire the e-drive for it!!
[I think you may have a wrong impression of transmission gear efficiency levels when the gears are under load. Now 45% is at the extreme end, just before the trans explodes, but 15-25% loss is the norm....1 or 2% difference doesn't really figure, loosing 25% loss DOES very much!! That is part of the efficiency hunt with the hybrid story, loose as much geared power-train as possible! THAT's where BIO need's to deal with the e-drive engineering buddies! What is more efficient? 6 smaller less efficient hub drives with their own little re-drives or 3 bigger, more efficient, direct drive motors going through a differential reduction and most likely a hub-reduction?]
.....and just to keep throwing it out there - I STILL do not yet discard the hydro-drive hub motors as a possible!
[Using 1 rear-drive axle as the main-drive unit and all other axles as aux-units, IF it should turn out that the MAIN-drive axle can harness enough re-gen, than you don't need the other axles for that - HOWEVER I do have my doubts about that. Breaking heavy shoots a LOT of Inertia forward - that means, there is a LOT of energy to be harvested on the forward axle(s). It is possible to harvest and store energy through the hydro-drive, they do it by storing some in cylinders with a gas-chamber - or spring loaded floating piston - to immediately harvest the energy again as soon as you need drive-power]
Maybe then you should stay away from anything that has a motor or "engine" anyway ......
I probably should. I might put an eye out.
But seriously, if the Liner requires that the driver go through pilot training and become an active part of the energy management system, then they might not sell very many.
dwh - you might find to learn your way around a sophisticated serial-hybrid way less challenging than your dual-brake pedal system!!
[I know F1 uses right accel - left brake, but that is not what most people will have in "their" system!
I think it would be way more challenging to read through the manual than the actual operation of the Terraliner-drive-system - actually I think that would be rather "boring simple"! - .....especially for those jocks that still know how to row a 16-speed....
IF you have a sophisticated ENERGY-CONTROL-SYSTEM, that takes topography into consideration, there is no choice than for you to plan ahead, if you want to max out efficiency.
However - you could even program the controller to consult the operator before reaching a decision point.
"Hello dwh!! It's me your AWESOME Terraliner! How are you today?" [Useless question, but might make you feel good! - switch off/on option when you configure initially!!] - [....after enough pause for you to be able to answer the previous useless question:] "Would you like to opt out of the downhill prep sequence?"
[...or alternately:] "Would you like to opt for the camp-on-top option?"
As we are talking "sophisticated" Terraliner we WILL have voice recognition and all you have to do is say: YES or NO [....maybe: "I am fine thanks!" first, IF you keep the make-feel-good option....]
And Terraliner will either keep the batteries where they are or get when reaching the pass or it will bleed down the batteries to have them empty for the down hill run (using the energy to still drive up the hill - of course you can program the default - keep the downhill sequence if there is no answer! Thisway you have all the break-energy storage available and should change your mind - you got a huge powerplant on board - just charge the batteries! ).
Most road-data is available for GPS today, so that should be little trouble to incorporate.
Anyway - I think if you are going Overlanding/Exploring you will HAVE to do some road-planning or WILL be in trouble shortly.....
BIO:
Mana: great artist, loved throughout S-America and beyond. LOADS of other Latin-speaking artists too....
Can't talk about Latino Music without mentioning Santana....
But learning to really love Latin culture -- which means loving countries like Italy, Spain, Portugal, and the Latin American countries -- that's another story.
I wouldn't know about Italy/Spain/Portugal - but Latin America is a entirely different story!
It may have become what it is today because of the European Latin countries, but has it's completely own identity today - it is very easy:
Not counting vacation....
You come to this part of the world (work or other obligations) and settle in - if after 6 weeks you can't take it, you never will. If you get the hang of Latino America you are probably useless for the rest of the world for the rest of your life!! :sombrero::sombrero::sombrero:
Also - there are huge differences between countries - Mexicans are not Latinos - they are MEXICANS!!
Chileans are not Latino either they are more GERMAN than Germany!! And Argentinians can't believe how many roads and streets in ITALY have "Argentinian" names!!
Cuban's are Caribbeans, but are actually are way more Latino than Chileans and Argentinians together!!
There is slight affiliation when they meet outside Latino America, just like Europeans start to stick together, but as soon as they are on home-turf again old rivalries are right back!
[...except for the French, ...these are ALWAYS french!!]
'nough for today!
thjakits
