Clutch slip issue

Technical discussion on converting internal combustion to electric
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Canberra32
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Clutch slip issue

Post by Canberra32 » Wed, 05 Dec 2012, 02:20

Ok here is a question I hope there is an easy answer to.

Is the power rating of a cluch going to be different with the way electric delivers power?

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BigMouse
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Clutch slip issue

Post by BigMouse » Wed, 05 Dec 2012, 03:01

Clutches are rated on torque, not power. Power is just torque X speed, and clutches don't care about speed.

There are probably dynamic effects which effect clutch performance, such as the ramp rate of applied torque, but with an electric, I expect a clutch would perform better than with an ICE since the clutch is not slipping when the car is accelerated from a stop. Slipping only happens when changing gears, and that's very brief and (should be) light.

I've been shopping for clutches for my car with the conversion in mind. Most aftermarket performance (street, not race) clutches I've found are good to 400Nm+, which should be good for an AC motor. DC is another story, with most conversions seeming to be clutchless.

EDIT: example: eBay link 342 ft lbs = 464Nm. My car's peak torque from the ICE is 180Nm by comparison. The 2.8L produces 280Nm, about what I expect from my ACIM.
Last edited by BigMouse on Tue, 04 Dec 2012, 16:07, edited 1 time in total.

Canberra32
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Clutch slip issue

Post by Canberra32 » Wed, 05 Dec 2012, 11:10

Well the motor is around 700 foot/pounds of torque slightly more than the Ls1 I took the clutch off :(
It's ok ill hunt down a big triple plate jobby sold have learned by now to just overkill it then not worry :)

Peter C in Canberra
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Clutch slip issue

Post by Peter C in Canberra » Wed, 05 Dec 2012, 16:18

For my conversion I left the clutch out and generally use only 3rd gear. Occasionally changing to 4th for sustained high speed (90+kph.
If the motor is just left with no load with a foot off the accelerator it should be OK to have a clutch. The commercial cars with regen like to have regen controlled by the accelerator pedal rather than the brake. The consequence is that they feel like they have engine braking but don't freewheel. Personally, if I had regen, I think I'd prefer to have it progressive in the first bit of travel of the brake pedal. To change gears with a clutch and with regen on the accelerator pedal you would also want a switch on the clutch pedal to turn off regen.
Daihatsu charade conversion 2009-18, demo iMiEV 2013-present, used Holden Volt 2018-present, on the ACT's 100%-renewable-by-2020 electricity.

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Johny
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Clutch slip issue

Post by Johny » Wed, 05 Dec 2012, 16:42

Peter C in Canberra wrote:The commercial cars with regen like to have regen controlled by the accelerator pedal rather than the brake.
The early iMiev was like that Peter but the Nissan LEAF (and apparently the later iMiev) have about 6-10kw when off throttle increasing to 30kW (LEAF) when the brake pedal is lightly pressed. So a bit of both.

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