# Electronic synchromesh shifting.



## Russco (Dec 23, 2008)

Or you could add a real dry disc *clutch* just like manual transmission cars have had for 100 years. Can't beat a clutch for a safety disconnect let alone quick shifting!


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## Crash (Oct 20, 2009)

I agree. I know that a clutch uses a few more amps, but the clutch really helps in safety and time. Put in a lightweight clutch/flywheel and save yourself some time. You may lose a whole mile out of all of your total range if your system is pretty efficient.


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## dimitri (May 16, 2008)

You guys don't get it, any idiot can put a clutch in, but Eric is finding ways to add new functions to his AC controller is just too cool, so he is sharing.

Good stuff Eric, keep it up and keep sharing!


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## etischer (Jun 16, 2008)

Thanks dimitri =)

If I were re-designing my car from scratch, I might add a clutch. I have that funny helical gear to deal with, so it's not as easy as you might think. I get along just fine using only 2nd gear, but thought others might benefit from the idea. 



dimitri said:


> You guys don't get it, any idiot can put a clutch in, but Eric is finding ways to add new functions to his AC controller is just too cool, so he is sharing.
> 
> Good stuff Eric, keep it up and keep sharing!


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## neanderthal (Jul 24, 2008)

wow very cool idea


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## etischer (Jun 16, 2008)

I am using regen now to match the motor speed, it works really well. The rpm snaps to the right speed, light turns on, and shifter pops right into gear. I have a few other ideas to try to make it even better =)


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## samborambo (Aug 27, 2008)

etischer said:


> I am using regen now to match the motor speed, it works really well. The rpm snaps to the right speed, light turns on, and shifter pops right into gear. I have a few other ideas to try to make it even better =)


Hi Eric,

We've been discussing the same idea of RPM matching over in another thread: http://www.diyelectriccar.com/forums/showthread.php/clutch-noi-41564p2.html

I'm really curious as to how you did this. Did you use a microcontroller or does your inverter have some PLC function built in? 

Sam.


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## etischer (Jun 16, 2008)

samborambo said:


> Hi Eric,
> 
> We've been discussing the same idea of RPM matching over in another thread: http://www.diyelectriccar.com/forums/showthread.php/clutch-noi-41564p2.html
> 
> ...


My inverter is programmable, I can even add a dual encoder card to do electronic line shafting =)


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## david85 (Nov 12, 2007)

I chatted with Louie Finkle on the phone about this idea last year. He figured that he could in theory make the motor/controller setup sensitive enough to detect drag from the syncros themselves, thereby achieving closed loop operation that auto adjusts for any gear ratio. I suggested using the neutral safety switch as the signal to the controller that its time to shift. However his setup would have been a brushless DC motor with hall sensors so it could have been easily controlled with servo like precision. I don't know how hard or easy it would be to do that with an AC motor but if nothing else, you can use a tach sensor for syncro purposes.

Never did do any business with Louie and I have no idea if he ever made anything like this.

When I did the brief test runs in my car, shifting usually took 1~2 seconds right at max RPM. Mid RPM shifting was basically as fast as you can grab next gear, and I have no clutch in mine either. Instead there is a weak electric brake function that works with the pedal released. This is what allows my car to shift clutchless so fast when others take much longer. Like that, its not unlike clutchless shifting an ICE car since the engine throttle will also draw RPM down in a predictable manner that can be anticipated by the driver. The disadvantage with mine is that it removes the ability to coast freely.

When ever I missed a shift, a quick blip of the throttle while holding the shifter to the correct gear was all I needed to get it in gear again. I could use method this to float gears and downshift as well but it took some concentration.

Adding an intelligent feedback to control motor RPM precisely would be a very nice feature indeed. I think its only a matter of time before controller manufacturers start integrating this. PLCs are such adaptable things that almost anything is possible.


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