# Clutches...



## X1/9jm (May 2, 2008)

It is my understanding that DC motors are not very good candidates for regen braking. This being the case, seems disengaging the motor entirely while going downhill would help in coasting situations, letting gravity do the work. Instead of pushing in the clutch pedal to coast, has anyone tried a centrifigul clutch in conjunction with the trans clutch? For the brief moments on a rolling hills road, the load would be reduced through slippage maybe extending battery life.

Also would the use of performance lightweight flywheels be much help in EV setups?


----------



## Coley (Jul 26, 2007)

"Freewheeling", with the clutch pushed down or the car in neutral is against the law in most states. Back in the 1930s, GM, I believe, actually had a free wheeling setup, but it was soon dropped.

Our cars don't have much drag from the motor, but they are still "in gear" so we are not breaking a law.

A lightened flywheel will help the synchros in the trans live longer and help acceleration (which eats a lot of amps).


----------



## X1/9jm (May 2, 2008)

I have never heard that allowing a car to freewheel down a hill was illegal in all my life. Thanks, I'll have to look into that. My son just finished driver's ed. and there was nothing about that. I knew it was not recommended due to the possibility of re-engaging the wrong gear but never illegal.


----------



## onesojourner (May 6, 2008)

I am also going to need some proof on that. I always take it out of gear and cost down hills.


----------



## trabant601 (Jan 20, 2008)

I am still in the planning stages of my project to EV a Trabant. The Trabant has freewheeling in 4th gear. I have wondered why on earth I should take out the clutch when it seems easier just to leave it in. 
I often pop the car out of gear to coast without using the clutch in 1st, 2nd, or 3rd. In 4th I can coast in 4th almost to a stop.
Can someone explain to me why I should remove the clutch to "keep it simple", because I do want to keep it simple? Thank you.


----------



## Coley (Jul 26, 2007)

Removing the clutch unit and the flywheel that goes with it, will take 25 or more pounds off your car. 

It is also easier (simpler) to connect the motor without the clutch.

Shifting has to be done a little slower, but you get used to it really quickly.

It is also one more thing to NOT have wear out!

3 of us in the area, did without the clutch and don't miss it....


----------



## DVR (Apr 10, 2008)

I've also read somewhere that 1 pound of rotational mass removed, gives the same performance increase as removing 10 pounds of dead weight. So then, "theoretically" that 25 pounds you save could be like putting your car on a 250 pound diet

Theoretically anyway


----------



## trabant601 (Jan 20, 2008)

The car empty weight is 620- 660 kg (1366.9 – 1455 lb.). 
It is originally 26 hp at 594 cc. The whole transmission probably weighs 25 lb. 
I do understand what I have been told above and will put it to my friends who will assist me (they know way more than I do about such things.)
The clutch will probably go.
Thanks


----------



## Manntis (May 22, 2008)

Coley said:


> Removing the clutch unit and the flywheel that goes with it, will take 25 or more pounds off your car.
> 
> It is also easier (simpler) to connect the motor without the clutch.
> 
> ...


In the first AC motor I installed, we drilled out the motor shaft and used it as the pilot bearing for the transmission input shaft. A simple spline adapter locked the two together. This enabled us to move the motor closer to the trasnmission than any coupler/clutch design, not only eliminating the weight of the clutch, flywheel, and hydraulic clutch assist but moving the engine mass closer to the center of the car for better handling


----------



## mattW (Sep 14, 2007)

Cough ***there is no wiki yet on clutch vs clutchless*** cough =P


----------



## KiwiEV (Jul 26, 2007)

As some of you may have already seen, on one of my videos there's a good example of clutchless "How to" and "How not to" gear changing on an EV:
http://nz.youtube.com/watch?v=rFrmjhKcAws
At 3:24 you can see someone changing gear in a hurry on my clutchless EV, and,
at 8:55 you can see how it's supposed to be done.

I'm not for or against clutchless vs clutched. What ever you're comfortable with.
The big benefit of keeping the clutch is easy, fast gear changes when you need them.
The big benefit of losing the clutch is simplicity and weight and possibly cost.


----------



## onesojourner (May 6, 2008)

Is there potential to get more range with a clutch? it seems like you could fine tune your gear shifts easier.


----------



## rebenergy (Apr 18, 2008)

_It is also easier (simpler) to connect the motor without the clutch.

Shifting has to be done a little slower, but you get used to it really quickly.

It is also one more thing to NOT have wear out!

3 of us in the area, did without the clutch and don't miss it...._

I recently bought a motor transmission set coupled with a love joy coupler. I was thinking of using a different transmission with clutch until reading this post. If what you say is correct, and I could shift gears without damage to this transmission, it would cut my building time considerably. I did think that low resistance from the traction motor would enable sifting without a clutch, but it seems too good to be true. 
I will follow this pose and watch your links.


----------



## rebenergy (Apr 18, 2008)

_As some of you may have already seen, on one of my videos there's a good example of clutchless "How to" and "How not to" gear changing on an EV:
http://nz.youtube.com/watch?v=rFrmjhKcAws
At 3:24 you can see someone changing gear in a hurry on my clutchless EV, and,
at 8:55 you can see how it's supposed to be done.

_

Sorry for my inept knowledge of U-Tube, but I could not find that info on U-Tube. I’ll keep searching.


----------



## mattW (Sep 14, 2007)

just click on the link


----------



## Coley (Jul 26, 2007)

To check it out a bit, try shifting your ICE car with a clutch, without using it.

Upshifting is usually easier but downshifting can be done as well.

Just don't force the shift. As your synchros in the trans try to equate the speed of the engine, you can feel resistane to the lever going into gear. 

This is normal, as the synchros are working.

Don't force it at this point, just keep a slight pressure and it will slip in.

My firends S-10 actually shifts better without the clutch than before.


----------



## michaeljayclark (Apr 3, 2008)

onesojourner said:


> I am also going to need some proof on that. I always take it out of gear and cost down hills.


it is illegal in vermont under chapter 25. 

http://www.leg.state.vt.us/statutes/fullchapter.cfm?Title=23&Chapter=025

I drove a commercial vehicle and during the driving test you had to have it in gear at all times or you failed.

Im sure it will fall under the law that you have to have control of the vehicle at all times. they give people tickets for spinning tires because they do not have control of the vehicle. coasting you do not have control even with brakes. the extra weight of the vehicle puts more pressure on the brakes then what they were designed to do, therefore you do not have control.

With all the laws on the books it menas NOONE can drive legally. It is impossible to follow every single law there is. If there were cameras recording every thing you did and mailed you a ticket for doing anything illegal everyone would be driving illegally and have their licenses suspended for points within a few days.

its just stupid. This goes to show if anyone makes an EV that works and coasts at any time guarantee that the manufacturers will have it shut down asap under the anti-coasting law.

so with this in mind to be legal you would have to have engine braking which is easily done with an AC motor. The DC motors that disengage when the accelerator pedal is not depressed is actually illegal.


----------



## Coley (Jul 26, 2007)

A DC motor doesn't "disengage" it just hasn't a huge amount of drag.

In the Saginaw overdrive unit that a lot of car manufactures used in the 50s and 60s, when you were not in overdrive, the trans would freewheel.

Since most of the time, the overdrive was used, there was no penalty because the trans was still in gear.

I would not think that our DC motors would be operating in a non-legal manner, as long as the trans was engaged.


----------



## X1/9jm (May 2, 2008)

Still can't find anywhere is says it's illgeal to caost out of gear.


----------



## X1/9jm (May 2, 2008)

Still can't find anywhere is says it's illegal to coast out of gear.


----------



## John (Sep 11, 2007)

http://www.leg.state.vt.us/statutes/...23&Chapter=025

Quote"(TT) § 1121. Coasting prohibited;"


----------



## rbgrn (Jul 24, 2007)

Don't forget about the big one...

(XX) § 1127. Unsafe control in presence of horses and
cattle;


----------



## X1/9jm (May 2, 2008)

Oh, ok, you live in Vermont. The link gave me an idea for starting point for a search in my state. After about 12 searches through N.C. statues using 3 different search engines I've found in N.C. it's not illegal to coast in neutral nor even mentioned. Best to check your area. I did find out on the net that it is a throw back law to a time before syncronized transmissions were widely used because on a large downgrade the brakes could fade and most didn't possess the skill to 'crash box' a tranny back into gear with the throttle, especially under stress. It also usually dealt with large trucks.


----------



## trabant601 (Jan 20, 2008)

It looks to me like that only applies to trucks and busses.
http://www.leg.state.vt.us/statutes/fullsection.cfm?Title=23&Chapter=013&Section=01121

The Vermont Statutes Online *Title 23: Motor Vehicles*

*Chapter 13: Operation Of Vehicles*

*1121. Coasting prohibited*




*§ 1121. Coasting prohibited*
(a) [Repealed.]
(b) No driver of a motor truck or motor bus, when traveling upon a downgrade, shall coast with the clutch disengaged. (Added 1971, No. 258 (Adj. Sess.), § 3, eff. March 1, 1973; amended 1997, No. 55, § 11(1), eff. June 26, 1997.)​


----------



## BHall (Aug 1, 2007)

I would really like to see them try to enforce this coasting law. Just like I would like to see them enforce the Oklahoma law regarding EV's with pack voltages greater than 80 volts! Last time I remember a normal ICE ignition coil has several thousand volts. It's all legislative bull [email protected] Out of site out of mind is what I say.

Brian


----------



## michaeljayclark (Apr 3, 2008)

X1/9jm said:


> Still can't find anywhere is says it's illegal to coast out of gear.



it is illegal in vermont under chapter 25. 

http://www.leg.state.vt.us/statutes/...23&Chapter=025

do a search on the page for coasting

many other states would consider a car out of gear not in control of the driver. the driver must have control of the vehicle at all times.

I was referring to the cars that do disengage the DC motor. as long as when you hit the accelerator and it goes I'd imagine you would be in compliance to having control of the car at all times.


----------



## Fatboy (Oct 30, 2007)

It's called "Georgia Overdrive" and is a federal law for trucks and busses.
I don't believe there is a car made that can't be slowed and stopped on any grade in the US without the help of the engine.

A lot of states still have a law on the books that says that a person with a white flag has to walk in front of a horseless carriage to warn the horses.

Coley,
The OD in the Fords coast in OD not Direct. My buddy had a 49 in HS and he was afraid of the OD.

FatBoy


----------



## Coley (Jul 26, 2007)

If the overdrive knob is pushed in, so that the OD can come on, then it freewheels until the governor kicks the solenoid in, as you speed up. 

When you then let up on the gas, the sun gear gets locked and the trans is in OD and NOT freewheeling.


----------



## DVR (Apr 10, 2008)

Fatboy said:


> It's called "Georgia Overdrive" and is a federal law for trucks and busses.
> I don't believe there is a car made that can't be slowed and stopped on any grade in the US without the help of the engine.


Well we are all in a lot of trouble with our EV's then!

Electric motors provide no braking whatsoever unless you have regen.


----------



## michaeljayclark (Apr 3, 2008)

a truck at 80,000 pounds out of gear going down a mountain is a VERY scary thing. First time I did that I overheated the brakes to the point by the time I was at the bottom of the mountain smoke was coming out of all 10 axles!!!
I learned my lesson quickly!

Hopefully someone will not put their ev into a runoff ramp and the next day we see "Electrical Vehicles Unsafe!"

Regen is BETTER than brakes in my opinion... little honda civic in full regen can almost stop on regen


----------



## X1/9jm (May 2, 2008)

Which brings us back to the original question. Since, in some states, it is not illegal, would some sort of centrifugal clutch on a DC non-regen setup be beneficial to extend the range by allowing a full on coast down hills?

As for brake fading, performance pads can be added as well as ventilated rotors and some strategic ducting for airflow over them.


----------



## DVR (Apr 10, 2008)

Dunno what real gains you would get in the down hill scenario. the motors dont really have that much resistance in them but they do have mass and that gives us something else to think about. The motor also acts as a flywheel during coasting. So putting a centrifugal clutch on it may (but maybe not) lessen the cars coasting ability on the flats.

'm only surmising but it seems logical


----------



## trabant601 (Jan 20, 2008)

These links and tips and those in the "Electric Trabant?" thread are great. I will certainly be in contact with appropriate people regarding advice and ideas.
I have made a small video of the donor Trabant in Indiana (perhaps the first electric Trabant in the USA), Rumpi might find others. 
I will post a link to show the donor video ASAP in the "Electric Trabant?" thread.
btw: I have decided to remove the clutch. All of the advice here has been great but... the mate with some knowhow and a welder said he will not help me if I leave it in. I am convinced. The Hungarian Youtube video didn't hurt either.
More soon in "Electric Trabant?" thread.
trabant601


----------



## adric22 (Jan 17, 2008)

One thing to keep in mind about coasting. At first I put my car in neutral as to remove the drag of the electric motor when coasting. But later on I realized the drag of the electric motor was so negligible that it didn't matter. But what I later discovered is that there is a benefit to leaving it in gear. Most of your DC electric motors have internal fans. When you leave it in gear, the motor is cooling itself as you coast. That is always a good thing. Once I started measuring the temperature of my motor, I realized I kept it much cooler when keeping it in gear all the time.

As for those dumb laws, I really see no difference at all in a coasting EV that is in neutral, or one that is in gear without the accelerator pedal being depressed. I suppose one might argue that if you needed to accelerate, it would take slightly longer to put the car in gear first. But I have never been in a situation in my gas car or my EV where I suddenly needed to accelerate when I was coasting to a stop. Even if I did, I'd likely be in the wrong gear for any acceleration anyway.


----------



## DVR (Apr 10, 2008)

adric22 said:


> Most of your DC electric motors have internal fans. When you leave it in gear, the motor is cooling itself as you coast. That is always a good thing. Once I started measuring the temperature of my motor, I realized I kept it much cooler when keeping it in gear all the time.


That is a VERY good point!


----------

