# Automatic Transmission question



## TheSGC (Nov 15, 2007)

I have been using my Automatic Transmission without modification. It just takes an extra second to get going, but no biggie. 

Although, if you want to get creative you can modify a PM motor to fit where the old starter was and have that idle your transmission, and when you hit the pedal have a switch disable the idling motor. Messing with clutches is not worth the work.


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## ClintK (Apr 27, 2008)

Wouldn't idling the main motor at a very low rpm when stopped be simpler / easier than rigging up a second motor? I can't imagine a second motor would be significantly more efficient, if at all.


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## skeeterb (Feb 6, 2009)

Hrmmm, I Haven't thought of that. Instead of removing the starter ring utilize it to use the small PM motor that would idle the transmission and would turn off the idle motor when the main motor gets to a certain RPM.


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## skeeterb (Feb 6, 2009)

ClintK said:


> Wouldn't idling the main motor at a very low rpm when stopped be simpler / easier than rigging up a second motor? I can't imagine a second motor would be significantly more efficient, if at all.


Wouldn't that require tweaking the controller? I'm new to this but I've been reading different sites about converting ICE cars to EV to help me get started. I'm thinking about going to Barnes & Noble or Books A Million and getting those books I've seen talked about on some of those different sites.


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## TheSGC (Nov 15, 2007)

Idling the main drive motor would be the most efficient, but the reality is most controllers won't let you do it. It would register as "High Pedal Lockout" and you would never be able to drive the EV. Actually, I don't know of any controllers that will let you do it.


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## ClintK (Apr 27, 2008)

skeeterb said:


> Wouldn't that require tweaking the controller? I'm new to this but I've been reading different sites about converting ICE cars to EV to help me get started. I'm thinking about going to Barnes & Noble or Books A Million and getting those books I've seen talked about on some of those different sites.


Someone may correct me and say "don't do that"... but I bet you could just adjust your Pot Box to go from say 300 Ohm to 5k Ohm. Then the motor will always be turning at least a little.

You could use a relay so the controller's high pedal lockout doesn't trigger. Also maybe set it up so the minimum resistance is only present in Drive?


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## skeeterb (Feb 6, 2009)

ClintK said:


> Someone may correct me and say "don't do that"... but I bet you could just adjust your Pot Box to go from say 300 Ohm to 5k Ohm. Then the motor will always be turning at least a little.
> 
> You could use a relay so the controller's high pedal lockout doesn't trigger. Also maybe set it up so the minimum resistance is only present in Drive?


The relay is a good idea. since there are switches on the transmission that would only let the engine start if the transmission were in Park or Neutral. It probably wouldn't be too hard to find the switch (sensor) and utilize it to control the relay when the transmission is in gear.


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## Jimdear2 (Oct 12, 2008)

skeeterb,

I've read that one fellow uses a BIG deep cycle 12 volt as his accessory battery and switches in 12 volts to his traction motor to idle it at stops. 

I believe you would need some contactors and switches to isolate the two systems but thats pretty simple.

Another method I have heard of is to use an external auxillary pump. It would be switched on when the throttle ius released to keep up pressure when the traction motor stops. I believe GM used this to modify one of their FWD transmissions for a Fleet Order limited production EV. The nice thing about the auxillary pump method is you could eliminate the very heavy and power wasting torque converter if you wanted to spend the time to make a direct pump and input shaft coupler.

Of course a small PM motor connected to the main motor with a gear or chain drive could, with a little creativity be switched in at throttle release to do regen and then at vehicle stop switch over to an idle drive motor. 

Lots of ideas to have fun with I'm sure ther are others out there.

Have fun, I sure am,
Jim


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## skeeterb (Feb 6, 2009)

I've got a 1990 Grand Am I am thinking about converting. It's got a Quad Four engine and automatic transmission. The body is in pretty good condition. Its the engine that went kaput. It was wrecked back in 96 but it was restored and driven for a while. It has over 100,000 miles on it so it was about time that the engine went kaput. The thing about repairing FWD vehicles is it's notoriously hard to get into the tight spaces to even get a belt on. After EV conversion, it wouldn't be very hard to get to the different parts to fix if you need to get to them.


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## skeeterb (Feb 6, 2009)

I found another thread here and it seems to be pretty informative. I was thinking of a small pump that is bypassed when the main motor is running driving the main pump but is activated when the accelerator is released. The pump would be put in one of the lines leading to the transmission cooler.


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## ClintK (Apr 27, 2008)

skeeterb said:


> I've got a 1990 Grand Am I am thinking about converting. It's got a Quad Four engine and automatic transmission. The body is in pretty good condition. Its the engine that went kaput. It was wrecked back in 96 but it was restored and driven for a while. It has over 100,000 miles on it so it was about time that the engine went kaput. The thing about repairing FWD vehicles is it's notoriously hard to get into the tight spaces to even get a belt on. After EV conversion, it wouldn't be very hard to get to the different parts to fix if you need to get to them.


My advice would be to compare how much time / money it would take to convert your auto Grand Am versus picking up a standard used car that may be more suitable.


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## electricmini (Oct 21, 2008)

I'm using an automatic in my Supra conversion.

The Supra's autobox can physically lock the torque converter up, eliminating most of its losses. Together with an aftermarket shifting computer, I'm hoping to be able to tweak the shifting & lockup to suit EV use.

I'm planning on using an auxilliary motor (a 3kW brushless servomotor) to idle the main Warp11 traction motor as I don't really want to mess with the Zilla's throttle input - not when it's capable of unleashing over 500 kW of power! Using the servomotor, even if its throttle goes crazy and commands full power, the maximum the brakes will have to resist is the much lower 3kW design power of the servo and its 10A controller.

It's a bit more complex than I'd like, but I'm hoping it'll work.

I considered using an auxilliary pump, but then you have to find one that can produce at least 60-odd PSI, withstand hot ATF, and you have to build/purchase the coupler to eliminate the torque converter.
I decided the auxilliary servomotor was a better bet, as it can run the aircon pump too ( so I can cut my range down to just 5 miles ;-)

Richard (electricmini)


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## skeeterb (Feb 6, 2009)

I'm not too sure of my Grand Am yet. I have to go to Barnes and Noble or Books-A-Million to buy a service manual for my car. I know cars from the late 80s early 90s weren't as complex as the roadster machines of today. There's still a lot of wires involved in the control of the ICE on my '90 Grand Am.


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## 1clue (Jul 21, 2008)

Might be more trouble than it's worth, but if you wanted to idle your motor to keep the pump going, then what about this:

You only want the pump going when you're not on the brakes, right?

So, you set it up so that your accelerator comes up not quite all the way, say maybe you have a spring that is not touched when you are driving normally, but when you let off the spring bumps the pedal mechanism to keep it turning at 500 rpm or so.

Now, you have the brake pedal. The brake has an arm that pushes the gas pedal the rest of the way up by pressing on that spring.

When you are at the light, you have your foot on the brake. The light turns green (or the opposing light turns yellow, depending on how you drive) and your foot comes off the brake. As you move your foot to the accelerator pedal, the motor is already spinning the pump, and as long as you're not driving like a teenager your tranny is probably going to be pressurized by the time you start pressing on the accelerator.

IMO, though, the above would not be as simple as adding an external electric oil pump, turned off when the brake lights are off.


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## skeeterb (Feb 6, 2009)

I'm new to this but I think idling the motor would be slightly inefficient use of power as it would constantly be using power from your battery pack leaving less power to drive longer distances. As to controlling the pump, a small 12V relay hooked to the Always open side of a relay controlled by the switch that turns on the brake lights would probably work to control the pump but there may be a lag because the pump would turn off before the motor re-engages turning the main pump. A microcontroller circuit would work also. I've played with a design that uses a PIC 16F628 microcontroller to control a Hydrogen on Demand system I've been playing with the designs of.


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## metalana (Jun 1, 2009)

Use a resistor to obtain say 400 rpm when in drive or reverse.



TheSGC said:


> Idling the main drive motor would be the most efficient, but the reality is most controllers won't let you do it. It would register as "High Pedal Lockout" and you would never be able to drive the EV. Actually, I don't know of any controllers that will let you do it.


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## Tesseract (Sep 27, 2008)

metalana said:


> Use a resistor to obtain say 400 rpm when in drive or reverse.


Actually, that doesn't work too well... throttle controls torque, not RPM, so a fixed resistor will result in a fixed current through the motor. As the tranny heats up or different loads are applied (a/c, p/s) the RPM will vary, sometimes quite a bit.

You need a proper PI or PID loop to regulate motor _voltage_ to maintain idle properly.

Also, this was covered in quite a bit of detail in this thread:

http://www.diyelectriccar.com/forum...s-why-automatic-gearboxes-work-evs-29101.html


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## TheSGC (Nov 15, 2007)

Tesseract said:


> Actually, that doesn't work too well... throttle controls torque, not RPM, so a fixed resistor will result in a fixed current through the motor. As the tranny heats up or different loads are applied (a/c, p/s) the RPM will vary, sometimes quite a bit.
> 
> You need a proper PI or PID loop to regulate motor _voltage_ to maintain idle properly.
> 
> ...


Bingo. I have a Zilla and use the resistor trick and it works pretty well, usually around 600-800 RPMs and pulling 50 motor AMPs on a cold day and about 20 motor AMPs when the transmission is nice and toasty. On the battery side I see 10 AMPs in the winter on start up and about 4-5 AMPs on those really hoy days. Part of me also thinks temperature drifts the resistor value and changes the duty cycle some what, but it seems happy for now, over 2,000 miles of EV fun. If I added other loads, that would probably be a different story.

Of course I have no other loads but I never get a hot motor from idling, and I have a switch to shut off idle when I am at slow stop lights.


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## Max57TBird (Mar 22, 2010)

skeeterb said:


> I've read that you can't use an automatic transmission without modification. The torque converter or pump could be kept moving using a secondary motor, but that would require alteration to the bellhousing of the the transmission and a kind of clutch mechanism to switch from the main motor to the secondary motor to keep the fluid moving. It would also be a bigger drain on the system. I'm new to this but I wanted to put my 2 cents in.


I'm not endorsing or recommending, but here is a snippit I received:

"Also, I just wanted to let you know that our company [ *Zigouras Engineering, Inc.] *now offers electric motor couplers for automatic transmissions. They replace the stock torque converter and allow direct drive; it allows automatic EV's to get almost the same fuel economy as EV's with standard transmissions. If you think you or anyone else could use one, feel free to visit us at www.ZigourasEngineering.com

Best Regards,
Paul"

I also learned that Justin at EvolveElectrics has made a deal with them to handle the product. Good luck with the conversion.


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## Coley (Jul 26, 2007)

Hooking a pump into the cooler lines probably is not a good idea, as the cooler lines feed from the pump to the cooler and then dump into the pan.
The resulting cooler fluid helps cool the fluid in the pan.


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## skeeterb (Feb 6, 2009)

It's been a while since I've posted here, but since then, I've gotten my Grand Am running better again. It was really nothing really seriously wrong with it. All it needed was to replace the IDI (Integrated Direct Ignition) housing, the 2 coil packs, boots, and spark plugs to get it running smoothly again. I may have goofed and messed up my O2sensor though. Other than that, that car has been taken out of my mind to be converted.


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## dimitri (May 16, 2008)

Max57TBird said:


> I'm not endorsing or recommending, but here is a snippit I received:
> 
> "Also, I just wanted to let you know that our company [ *Zigouras Engineering, Inc.] *now offers electric motor couplers for automatic transmissions. They replace the stock torque converter and allow direct drive; it allows automatic EV's to get almost the same fuel economy as EV's with standard transmissions. If you think you or anyone else could use one, feel free to visit us at www.ZigourasEngineering.com
> 
> ...


I hope their motor couplers are better than their math skills, because this quote from their site made me LOL 



> In doing so, our couplers eliminate the massive energy losses that are associated with a torque converter, and can improve EV fuel economy by over 60%.


I have almost 10,000 EV miles with stock torque converter and get the same or better range than similar conversions with manual transmissions. So, I wonder, how can I get 60% improvement on top of that?


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