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Old 03-13-2009, 02:21 PM
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Arrow The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

Who am I?
A gearhead like you are. I now make a living in technology but am a certified journeyman mechanic as well. I'm in my mid-fifties and old enough to know when I'm beat and how to capitalize on other peoples work as well as their mistakes. I currently do racecar fabrication and I drive as well during those hours that Corp. America does not have her hooks in me. Like many gearheads, I have more projects than time.. When I crossed the boundary into my 50's I realized that I was burning hours on the sofa in front of the idiot box that I'd never recover. So I guess now I've traded seats and now spend at least some of that time in front of my PC whilst enriching myself on the Internet. During my years turning wrenches - I've been through many automatic transmissions. Of course I was baptised by fire when thrown into the deep end with a Turbo-400 from a pickup truck was assigned to me. (worked like a charm thank you).. I've a thorough understanding of these myterious slush boxes and have grown to both love and hate each one of them equally.
I've had a dream since I was 10 years old to build a series hybrid. Yes over 4.5 decades ago. It was then that my Grand Pa (a brilliant engineer) and I sat down at the rail yards and he taught me how the "new" Diesel Locomotives worked.
It was that principle that I wanted to use (in essence) in the creation of my own EV. Start out building and refining the car as an EV and adding Waste-oil diesel generator to the mix for a range extender.
I have my own Mill and Lathe and, of course, welders.
Enough about me..

I've read through nearly 30 pages of YES YOU CAN and NO YOU CAN'T on the "other" thread.. I've addressed some of those issues here (if you can stand reading that much)..

I'd ask one thing of the participants to this thread -
Please keep on topic. Those of you that want to say how rediculous the idea is - please see other thread.

On with the show....
I see many people touting the line - "Well if you wanted a standard - why didn't you start out with one, that's what you're making your automatic into anyways!" Guys - read the PROs below - that's why..

PROs -
- Automatic is lighter
- Automatic does have "ParK" selector - Go ahead and use the parking brake on a Northern car that's 15 years old - You'll be calling a tow to the shop to un-freeze your rusted cables.
- Automatics are less intimidating to people that have never driven a std
- Many really good prospective donors have been passed up due to their transmission
- Conversion to a stick requires not only the transmission but retrofitting the shifter from auto to std.

Addressing the Green-ness -
- Automatic trans fluid can be recycled along with regular motor oil.
- ATF can be burned for heat very efficiently with super low emissions (it's done frequently up north here).
- Volume of ATF required is dramatically reduced over what's required with a torque convertor.
- Fire potential of the ATF? yes it will burn but you can pour it on a hot exhaust manifold and it will not ignite. It needs to be vaporized first just like diesel fuel or gasoline for that matter. I also think that the potential for fire and explosion is far greater from batteries not put inside of protective casings with crush-zones around them.

Various Notes made during the consumption of the "other" thread -
- Idling the traction motor to maintain pressure is out of the question in my estimation. Keep reading for more..
- Pressure leakage internally is minimal with a transmission in good condition. I've seen a transmission maintain pressure for as long as 30 minutes.
- Slippage on start-up - I don't think this is as big of a problem as some have stated it to be. Point in fact, you do want "some" slippage between shifts and startup due to the high levels of torque in the electric motor at lower RPM. Slippage and the torque convertor (not needed here) are where the vast majority of heat is created in an automatic trans.
- Most transmissions made since 1984 are controlled by the ECU or ETC (I-E Electronically controlled).
The interface to control it can be made quite simply since the actual control inputs to the transmission are binary (on or off). I would suggest that shifting of the transmission still be kept manual with a 4 positions controlled by the shifter. 2nd gear, Neutral, 4th gear (highest 1:1 rather than an OD) and Reverse. If you want to retain fully automatic controls, you could do that as well but with a higher degree of complexity.

If you have a transmission that's a bit of an internal bleeder - you could either overhaul it with new seals and gaskets or add an external accumulator. The Accumulator would have a low pressure switch to engage external pump motor to build pressure to a specific level (40 PSI would be enough). Depending upon the weight of the vehicle, you'll need between 40 and 100 PSI to keep clutch packs engaged without slipping. If you want to hot-rod it, you better be looking for pressures double that.

Speaking of Clutch Packs - I don't know of any automatic transmission shipped in a car that has bands any longer. They all use clutch packs now days. Clutch packs have far more friction / surface area than do bands so they require less pressure to operate properly.

Regeneration: Yes, the wheels will backfeed torque through the transmission to capitalize on Regen if using the AC drive system and appropriate controller(s).

Additional issues to be taken into consideration -
The input shaft of the standard transmission locates between the Pilot bearing and the front bearing of the transmission. This would have to be taken into consideration while making an adapter. This noted - the adapter will need to drive the pump of the transmission and be locked to the input shaft of the trans.

Let's have fun!
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Last edited by Big-Foot; 03-13-2009 at 08:22 PM. Reason: Cleaned up some Schpellink errors and punktiation
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  #2  
Old 03-13-2009, 02:46 PM
aeroscott aeroscott is offline
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

well put . I didn't know they were lighter except for the gm 2 speed . I've been posting about using transverse transaxle in order to get rid of the hypoid differantail and it's losses .gm and Honda makes lots of these . have you worked with them .
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Old 03-13-2009, 02:51 PM
TheSGC TheSGC is offline
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

I was itching to start this thread soon anyways...

I have an Automantic Transmission in my 1996 Civic EV and I have 135 EV miles going for me at the moment. So with that, here is my thoughts so far:

The coupling I have is the same as a clutch-type setup, making any torque converter mods unnecessary. I also found that creating a Torque Converter bypass (i.e. removing it) was a bad idea since it's the main pressure regulator in the Honda Transmission.

I am using a Honda A4RA 4 Speed Automatic Transmission with the following gear ratios, including Final Drive:
1st- 11.31
2nd- 6.38
3rd- 4.02
4th- 2.77

Shifter Selections: D2, D3, D4, N, R, P.

I usually start off in D3 and when it shifts into 2nd, I shift into D2 and the gear stays in second. It's usually good up to 40 MPH with my little 6.7" motor. However, in D2 the torque converter is not locked. It will lock in D3 and D4, and I will be testing those gears once my new 9.1" is installed.

The 1996 Honda Civic does have a PCM that is not too picky about sensors. That said, I would recommend making a new TPS sensor that connects to your POTBOX. It would help acceleration and better shifting vs the limp mode of shifting at different MPH instead of logical data, like throttle position, hill climbing, deaccel, etc.

I do not idle my motor. I throw it into gear and lightly press the accelerator until the cluthes engage, then I step on it. It doesn't do any damage to the transmission since the PCM will not engage the clutches until pressure is built up and a certain RPM is reached. So idling would just be a wast of power.

The only beef I have with the setup is that the Torque Converter doesn't lock in 2nd gear. That will be a simple fix, literally just adding a swtich to activate the 12 volt lockup.

Now for some data/specs:
1996 Civic EV
6.7" K99-4007 Motor
Kelly KDH09401 400 AMP Controller
96 Volts using 8 MAXX29 12 volt 125 AH deep cycles from Wally World.

I live in an extremely hilly area, and my initial Winter tests show I use about 350 WH/Mi doing 35-40 MPH. My motor is about 73% efficient at the RPMs I am using it at (yeah, sucks hence the FB1-4001A upgrade) and I estimate that my WH/Mi should go down to 260 WH/Mi with the new motor and using D3 for locking Torque Converter.
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Old 03-13-2009, 03:23 PM
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

Hear hear, thanks for starting this thread. Although I am just starting to learn about transmissions, I am building EV with auto and convinced that it will be great. I agree with all your points, those are all same reasons I picked the auto. However, I decided to keep TC mainly because I am not comfortable enough with innerworkings of the auto transmission to disrupt its fluid path and volume. Perhaps I will learn something from you and remove TC on my next conversion.
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Old 03-13-2009, 05:21 PM
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

Awesome post, Big-Foot! It looks like I will be getting a chance to test out some of your ideas/theories with Dimitri here as we merge his automatic Mazda with my new controller. It would be ironic and humorous if it turns out Dimitri doesn't need to idle the tranny at all to maintain crisp off-the-line response!
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Old 03-13-2009, 07:05 PM
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

Bigfoot,

WOW ! ! ! it's great to see someone else who beleives that an automatic is a good answer to EV conversions. You sure covered the ground better then I did.

Your personal history sounds a lot like mine, except I have 10 years on you and went tractor pulling indtead of racing. I am a certified Master Technician and was a licensed aircraft tech. I also went into the tech world (automotive specification databases). Got away from the BOOB tube (haven't turned it on in about 10 years. I left it in the corner so I could snear at it ocassionaly. Went to computers in the late eighties and love it.

I have started a couple of threads about automatics in EVs, but I think I was too specific in concintrating on the powerglide to really build general interest.

One problem with EV converters, is a lot of them are fixated on the BIG torque at low RPM of electric motors and seem to resist the idea of a transmission, finally, in the end, settling on a manual transmission because it is in the end easier to install the motor and that is the way everyone does it.

I have been reading these threads for a long time and a lot of people keep saying they want a two speed because all they normally use and need in their 5 speed manual is 2nd and 3rd or 4th.

I kept promoting the powerglide because it is probably the most flexible, strongest, easiest to modify transmission out there that I am comfortable with, AND it,s a two speed with the perfect ratios for electrics motors when used with differential ratios in the mid threes, 1:82 to 1 and 1 to 1, plus it has a Park.

I have pushed the glide in versions from a fully automatic torque converteless replacement for any RWD transmission, to a fully modified shorty turned sideways without bell housing to be used in three wheelers using chain drive.

Ouch, here I go again ranting on about the powerglide.

I mostly got just mild O hum interest and back to "you don't need a transmission if you motor is big enough".

It seems that there are two groups using automatic, those who thought it out and saw the value and those who were forced into it because of circumstances and later became believers.

I know that a lot of the people who have responded to this thread under stand that torque multiplication throught gear reduction allows the use of lighter, higher voltage more efficient motors and battery packs.

Another factor that is addressed by using automatic in conversion is that a vehicle is produced that is more of a "just get behind the wheel" drivable vehicle. No special instruction and scarry procedures.

A lot easier to promote EV that way.

I got to admit that the other way of adapting stuff can be more fun to the DIYer though.

When I started the EV conversion of my tractors, I made a decision not to build a street vehicle because my health precluded the effort. I get the impression that some here brush off what I say because I haven't done a car, plus I'm a bit wordy and not too politic (plus a very poor typest and speller) in my response to comments. I hope not.

Anyway you all have my support and any ideas and information I have available as you go forward.

Good Luck and make believers.
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Old 03-13-2009, 07:50 PM
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

I think it may also have a lot to do with the fact that most of us have enough to deal with in a conversion besides trying to make an automatic work, and the prevailing thought of those who came before us is that autos are less desirable. Not saying that's necessarily correct, but I, (and I suspect others), am not willing to go spend money on an auto to replace the manual I already have, for potential unknown results.
I appreciate your ideas and would like to see some people make these work, I'll let others work out the kinks
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Old 03-13-2009, 08:23 PM
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

Quote:
Originally Posted by JRP3 View Post
I think it may also have a lot to do with the fact that most of us have enough to deal with in a conversion besides trying to make an automatic work, and the prevailing thought of those who came before us is that autos are less desirable. Not saying that's necessarily correct, but I, (and I suspect others), am not willing to go spend money on an auto to replace the manual I already have, for potential unknown results.
I appreciate your ideas and would like to see some people make these work, I'll let others work out the kinks
Yeh, I understand where you'er coming from.

I have always been one to go ouside the box and sometimes I don't understand why others wont go there as well. You are a bit of an outside the box thinker yourself (not everyone would do a conversion on a six wheeler). But I think you have a tighter hold on reality then I do.

I love pushing the envelope, Look at a rear engined pulling tractor built from a FWD axle, a twin water cooled motorcycle engined pulling tractor using a powerglide with high stall converter. Now I'm converting to electric. All of them "Just Because" someone said it won't work. I've done the required research (you guys all helped with the research) and now know that it will, I just don't tell them yet.

Still . . . If someone in my area want's to do a powerglide, I'll give as much help as I'm phisically able. Just PM me. Big foot can tell you that switching out a trans is a lot easier then you might think.

PS
If it's OK with you (please respond), I would like to PM you with some specific questions about what you recommend on six wheelers (you already gave me some general stuff). I'll be out and about and will start looking for a donor.
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Old 03-13-2009, 08:49 PM
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Quote:
PS
If it's OK with you (please respond), I would like to PM you with some specific questions about what you recommend on six wheelers (you already gave me some general stuff).
Go ahead, hit me up.
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Old 03-13-2009, 09:08 PM
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Default Re: The Reasons why Automatic Gearboxes WILL Work with EV's & how to do it..

I guess one "pro" for running an automatic is that the fluid medium acts to absorb driveline vibrations.
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