# [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ? Coupler ?



## EVDL List (Jul 27, 2007)

A flywheel in a gas car is usually close to the motor, or even inset into the motor in some cases. When you hang the flywheel on an electric motor, it usually sticks out a ways, hence the need for a bellhousing-like mount. To get my flywheel close to the electric motor, I would have to move in the shaft bearing, cut short the output shaft, and bore a deep hole for the tranny pilot shaft. It is much easier to just build out a spacer. This will also make life much easier if I every have to swap in another motor.

You can make the spacer adjustable (in the axial direction) by stacking various thicknesses of material, or precisely machining the spacer thickness.



----- Original Message ----
From: Alternative Energy Guy <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Wednesday, July 9, 2008 10:19:54 AM
Subject: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ? Coupler ?

... I am wondering why one would need a full bellhousing adapter to mount
the motor. Couldn't one make a plate that bolted to the transmission
and off of that make an adjustable motor base that could be adjusted to
align the motor shaft to the transmission shaft? ...



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## EVDL List (Jul 27, 2007)

OK,
I'll bite. What is the flywheel needed for? Why not direct connect the motor
shaft to the transmission input shaft?

Mark Grasser
Eliot, ME

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of David Dymaxion
Sent: Wednesday, July 09, 2008 1:19 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless
? Coupler ?

A flywheel in a gas car is usually close to the motor, or even inset into
the motor in some cases. When you hang the flywheel on an electric motor, it
usually sticks out a ways, hence the need for a bellhousing-like mount. To
get my flywheel close to the electric motor, I would have to move in the
shaft bearing, cut short the output shaft, and bore a deep hole for the
tranny pilot shaft. It is much easier to just build out a spacer. This will
also make life much easier if I every have to swap in another motor.

You can make the spacer adjustable (in the axial direction) by stacking
various thicknesses of material, or precisely machining the spacer
thickness.



----- Original Message ----
From: Alternative Energy Guy <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Wednesday, July 9, 2008 10:19:54 AM
Subject: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ?
Coupler ?

... I am wondering why one would need a full bellhousing adapter to mount
the motor. Couldn't one make a plate that bolted to the transmission
and off of that make an adjustable motor base that could be adjusted to
align the motor shaft to the transmission shaft? ...



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## EVDL List (Jul 27, 2007)

> David Dymaxion wrote:
> > A flywheel in a gas car is usually close to the motor, or even inset
> > into the motor in some cases. When you hang the flywheel on an
> > electric motor, it usually sticks out a ways
> ...


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## EVDL List (Jul 27, 2007)

> Alternative Energy Guy wrote:
> > If I am not using a clutch, why do I need a flywheel ?
> 
> That's the rub. Many conversions DO use the clutch. Mine will for sure.
> ...


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## EVDL List (Jul 27, 2007)

You are right you don't have to use a flywheel and clutch, but there are reasons some folks retain them.

o You can usually shift faster with a clutch, particularly for downshifts

o The springs in the pressure plate provide some shock relief for the electric motor and the u-joint or cv-joint bearings


o If you have a runaway motor you can press in the clutch. Under the high torque of an electric motor you might not be strong enough to pull it out of gear in an emergency runaway (the tranny is designed to stay in gear under torque, not pop out of gear). You also might not be strong enough to get the car to stop with the brakes. You then absolutely need a reliable electrical disconnect for the full shorted battery power.

o You can let the motor keep spinning fast when you stop, and recover a little energy the next time you take off

o If your controller is jerky, you can slip the clutch for a smoother takeoff

There are some advantages to getting rid of the clutch/flywheel:

o A bit lighter

o Less rotational weight

o Possibly simpler to build


----- Original Message ----
From: Alternative Energy Guy <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Wednesday, July 9, 2008 11:47:34 AM
Subject: Re: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ? Coupler ?

If I am not using a clutch, why do I need a flywheel ? ICEs have them
so that the engine has enough inertia to keep running between power
strokes. An electric motor doesn't need one.

----- Original Message ----
From: Mark Grasser <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Wednesday, July 9, 2008 11:29:37 AM
Subject: Re: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ? Coupler ?

OK, I'll bite. What is the flywheel needed for? Why not direct connect the motor
shaft to the transmission input shaft?



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## EVDL List (Jul 27, 2007)

> David Dymaxion wrote:
> > You are right you don't have to use a flywheel and clutch, but there are reasons some folks retain them.
> >
> > o You can usually shift faster with a clutch, particularly for downshifts
> ...


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## EVDL List (Jul 27, 2007)

Go for it! How are you planning on indicating to the motor controller
which gear you want to shift into?


On Wed, Jul 9, 2008 at 9:19 AM, Alternative Energy Guy


> <[email protected]> wrote:
> 
> >
> > When I want to shift gears, I am going to break the motor torque, shift
> ...


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## EVDL List (Jul 27, 2007)

> Peter Gabrielsson wrote:
> > Go for it! How are you planning on indicating to the motor controller
> > which gear you want to shift into?
> 
> ...


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## EVDL List (Jul 27, 2007)

> Go for it! How are you planning on indicating to the motor controller
> which gear you want to shift into?

Ah, that's easy... all you need is a brain machine interface with
predictive capabilities. And sensors to detect the location of the
gearshift. That and the software to override the throttle position based
on sensor input from vehicle speed, motor RPM, gear shift position, brain
waves, etc.

That's got to be much easier to implement than a clutch, and more reliable
too. <rolls eyes>

>
>
> On Wed, Jul 9, 2008 at 9:19 AM, Alternative Energy Guy


> > <[email protected]> wrote:
> >
> >>
> >> When I want to shift gears, I am going to break the motor torque, shift
> ...


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## EVDL List (Jul 27, 2007)

Generally agreed, just a couple of counterpoints to counterpoints (comments interspersed):



----- Original Message ----
From: Alternative Energy Guy <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Wednesday, July 9, 2008 1:04:20 PM
Subject: Re: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ? Coupler ?

<snippage>

> o The springs in the pressure plate provide some shock relief for the electric motor and the u-joint or cv-joint bearings

>> ICEs produce power pulses 2, 3 or 4x per revolution. That is the need
for the shock absorption. I don't think anything can happen at the
wheels to send shock through the driveline to the input shaft that will
require damping.

A pothole, or even turning with a limited slip different, can send some shocks towards the motor. On my ice, I can sometimes hear a "clunk-clunk-clunk" as the driveshaft gets banged back and forth. The springs make this a less stressful event on the u-joints. If you are racing and have wheel hop, this can destroy parts of your driveline -- wheel hop would certainly send shocks up the driveline. I suspect it is not a big effect and you would likely get away with no springs.

> o If you have a runaway motor you can press in the clutch. Under the high torque of an electric motor you might not be strong enough to pull it out of gear in an emergency runaway (the tranny is designed to stay in gear under torque, not pop out of gear). You also might not be strong enough to get the car to stop with the brakes. You then absolutely need a reliable electrical disconnect for the full shorted battery power.

>> I'm using an AC motor. If the transistors fail closed circuit, it will
burn a motor winding.

You are probably less likely, but still not immune from a runaway (the pedal could stick, for instance) -- you still should have a very reliable disconnect.

> o You can let the motor keep spinning fast when you stop, and recover a little energy the next time you take off

>> Regenerative braking.

Agreed, regen is better!

> There are some advantages to getting rid of the clutch/flywheel:
> 
> o A bit lighter 

>> 15 to 40 pounds, depending on the vehicle.

I have a racing flywheel and pressure plate for my conversion, and lost around 10 pounds of rotational weight, and would lose another 10 if I eliminated them. I think I'll gain more acceleration by the changeable gear ratios and less time spent shifting than by the 0.3% weight loss (effectively 1% since it is geared weight).



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## EVDL List (Jul 27, 2007)

On Wed, 9 Jul 2008 13:29:37 -0400, "Mark Grasser" <[email protected]>


> wrote:
> 
> >OK,
> >I'll bite. What is the flywheel needed for?
> ...


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## EVDL List (Jul 27, 2007)

> From: [email protected]
> To: [email protected]
> Date: Fri, 11 Jul 2008 01:40:38 -0400
> Subject: Re: [EVDL] Adjustable motor/transmission adapter/mount ?	Clutchless	? Coupler ?
> 
> On Wed, 9 Jul 2008 13:29:37 -0400, "Mark Grasser" <[email protected]>


> > wrote:
> >
> > >OK,
> > >I'll bite. What is the flywheel needed for?
> ...


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## EVDL List (Jul 27, 2007)

I'm farting around with this right now, balancing most of the issues y'all
have brought up.
Ideally, I'd love to try it with the clutch, then remove it, and see how
things do. It's my first EV,
so I have no idea what I'll end up liking. I will need a transmission, as
we have real hills,
and I want to hit the highway occasionally. Probably will only need 2 or 3
of the ratios, though...

One of the problems with ditching the clutch is that there is a boatload of
inertia in the motor armature,
and my little transaxle (small to reduce weight and rotational inerta, and
also to package well with my shell)
has little synchros. So I'm going to do it the clutch way first- and see if
I can shift without it.

And while I can rev- match pretty well, a synchronized transmission is
actually quite a bit harder to
shift clutchless than a straight- cut or dog box... I too thought about a
sensor on each shaft of the transmission,
control electronics, and an 'up/down' button, but yipes, I want to drive
this thing before I die!

As to flywheel mass, that's what lathes are for, I think. Even so, there's
going to be #25 of friction plate,
pressure plate and disc in a 10" disc inside the transaxle's bell housing.
Lastly, I'd like to make this car friendly enough that Jenn will use it, and
she's going to want a clutch.
Maybe I should add a rev- limiter while I'm in there, I'm thinking...

Just rambling,
Toby
Seattle
BMW 2002 with a VW Fox transaxle, mostly for packaging reasons...


> Neon John <[email protected]> wrote:
> 
> > . I bet that the moment of inertia of a long narrow DC armature
> > isn't much, if any, more than that of the clutch disc.
> ...


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## EVDL List (Jul 27, 2007)

On Fri, 11 Jul 2008 10:17:52 -0400, Phil Marino <[email protected]>


> wrote:
> 
> 
> >> For that matter, with RWD vehicles where the owner doesn't plan on shifting, I
> ...


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## EVDL List (Jul 27, 2007)

>>But there are advantages to keeping a transmission that you do shift. It
>> has to do with motor torque.
>
> Kinda obvious. My question is, how many EVers shift? My impression from
> reading this list is that few do. True?

I do, I only use 2nd and 3rd, but I do shift between them. 2nd up to
about 30-35 and 3rd for anything above that.

> For those who do shift, how many have done anything to reduce the
> inefficiency
> of a regular automotive transmission? Things such as removing unused
> gears,
> removing the reverse gear if a reversing contactor is used, converting to

A manual transmission is typically better than 90% efficient. In fact, as
I recall the transmission AND differential is around 90% with the bulk of
the losses in the diff.

Removing extra gears will probably gain you less than 1% efficiency,
hardly seems worth the effort, however, I have read about a couple folks
who have done this.

I can't think of anyone that has a manual and has elected to pay the price
for a reversing contactor rather than using the reverse gear. Seems like
an awfully expensive solution to basically a non-problem.

> low
> viscosity oil, reducing the oil level to the minimum, things like that.

Oh yeah, definitely. Royal Purple synthetic oil. Good stuff, made a
small improvement in my energy consumption. Not much, but a little.




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## EVDL List (Jul 27, 2007)

John, I run synthetic tranny and differential fluid as they improve efficiency at all speeds, especially in the winter months. I use 2nd and 3rd gears in my Toyota pickup. The cheapest way to improve overall efficiency IMO? Slow down 5 mph!



----- Original Message ----
From: Neon John <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Saturday, July 12, 2008 1:56:16 AM
Subject: Re: [EVDL] Adjustable motor/transmission adapter/mount ? Clutchless ? Coupler ?

Kinda obvious. My question is, how many EVers shift? My impression from
reading this list is that few do. True?

For those who do shift, how many have done anything to reduce the inefficiency
of a regular automotive transmission? 




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## EVDL List (Jul 27, 2007)

>> how many EVers shift? My impression from reading this list is that
>> few do. True?



> Peter VanDerWal wrote:
> > I do, I only use 2nd and 3rd, but I do shift between them. 2nd up to
> > about 30-35 and 3rd for anything above that.
> 
> ...


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## EVDL List (Jul 27, 2007)

What are the thoughts of using a Tiptonic style transmission.

I'm looking at a Boxster -- and they have both 5 speeds and Tiptronics

Mike







> Lee Hart wrote:
> >
> >>> how many EVers shift? My impression from reading this list is that
> >>> few do. True?
> ...


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## EVDL List (Jul 27, 2007)

I wish we had the fiat 850 convertible you guys get up there
rear engined they are a perfect candidate with their sleek
lines and lightweight construction.




> me2 wrote:
> >
> > I'm throwing ideas around in my head for the motor mount and
> > transmission adapter for my EV.
> ...


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