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Author: Subject: Electric Reverse Trike
Sam_68

posted on 22/11/15 at 03:47 PM Reply With Quote
quote:
Originally posted by smart51
In my example the engine will be on most of the time. The battery will supply the extra power for acceleration and hill climbing, with the surplus power from the generator charging the battery the rest of the time.


Then you'd probably be better off with the IC engine driving the wheels directly, with the electric motor to assist it (Integrated Motor Assist - the Honda approach), rather than acting as a generator.

Every time you force energy to change form there is a percentage loss in efficiency, so it doesn't usually make sense to make your primary source of power change its form many times on its way to the wheels (chemical>heat>mechanical>electrical>chemical>electrical>mechanical in your example).

That's why operating regime is so crucial to how effective different forms of hybrids are: Range Extender PHEVs are at their best when most of their journeys are short enough to be pure electric (city or local driving), whereas IMA works best on longer/faster motorway and open road driving.

Get the balance wrong, and one half of your hybrid powertrain is little more than dead weight.

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smart51

posted on 22/11/15 at 06:25 PM Reply With Quote
quote:
Originally posted by Sam_68
quote:
Originally posted by smart51
In my example the engine will be on most of the time. The battery will supply the extra power for acceleration and hill climbing, with the surplus power from the generator charging the battery the rest of the time.


Then you'd probably be better off with the IC engine driving the wheels directly, with the electric motor to assist it (Integrated Motor Assist - the Honda approach), rather than acting as a generator.

Every time you force energy to change form there is a percentage loss in efficiency, so it doesn't usually make sense to make your primary source of power change its form many times on its way to the wheels (chemical>heat>mechanical>electrical>chemical>electrical>mechanical in your example).

That's why operating regime is so crucial to how effective different forms of hybrids are: Range Extender PHEVs are at their best when most of their journeys are short enough to be pure electric (city or local driving), whereas IMA works best on longer/faster motorway and open road driving.

Get the balance wrong, and one half of your hybrid powertrain is little more than dead weight.


Decent generators, motors and drive electronics are similarly efficient to a gearbox, differential and drive shafts. The advantages of electric drive are that the engine is always operating at its most efficient point, and that it can be turned off when stationary or when the batteries are fully charged. You get regen braking too.

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ro

posted on 22/11/15 at 06:32 PM Reply With Quote
OK, after trying lots of designs, I have given up on the idea of widening the body and putting the batteries down the side. I just could not make it look any good

I think I've now virtually nailed the design. 6x55ah batteries up front. Wishbones and steering reversed to make extra room for the batteries. Seat canted to allow a "legs bent" driving position gives me more room at the front.




I've also moved the floor above the cross braces and slightly increased the length of the rear section to allow more access to the motor.



Unfortunately I could not find a way of mounting the motor co-axially with the swingarm without drastically increasing the width of the whole trike

quote:
Originally posted by Volvorsport
Is there not a battery pack that comes from a hybrid that you can use already?

quote:
Originally posted by ettore bugattiI guess getting an affordable drive train (motor batteries) is the main challenge.

Yeah, balancing cost, weight, power and range seems to be the main challenge with this project. Unfortunately all existing hybrid batteries seem to be a) really bloody expensive and b) really high voltage.

quote:
Originally posted by blakep82
Along with that roll hoop, I would perhaps have another look at the top wishbone mounts too, look like a little leverage would have them ripped off the tube with the length of them?

Do these ones look any better?

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Volvorsport

posted on 22/11/15 at 06:53 PM Reply With Quote
I've found a certain French small car manufacturer has a subframe where all the bits happily Bolt on





www.dbsmotorsport.co.uk
getting dirty under a bus

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smart51

posted on 22/11/15 at 06:56 PM Reply With Quote
quote:
Unfortunately I could not find a way of mounting the motor co-axially with the swingarm without drastically increasing the width of the whole trike


How about mounting the motor on the rear swing arm? That way the distance between the motor and rear wheel will never change. Mount the motor over the pivot point and it will not add much to the unsprung weight. Mount it forward of the pivot point and it will counterbalance the unsprung weight of the rear wheel.

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ro

posted on 22/11/15 at 07:09 PM Reply With Quote
quote:
Originally posted by smart51
How about mounting the motor on the rear swing arm...

Nice idea! For now, in the name of keeping it simple before the IVA, I have bought a second hand swing arm and wheel assembly.

However, if I was to fabricate a new swing arm (with motor) after this is on the road, I could use the space that the motor currently takes up to mount a small generator. Hmmm, I like that idea. I REALLY like that idea! I'll make sure there's enough room back there...

Anyway, I'm trying hard to keep this simple to start with otherwise I may never finish it - I have a bad habit of overcomplicating projects and not finishing them!

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Sam_68

posted on 22/11/15 at 07:14 PM Reply With Quote
quote:
Originally posted by Volvorsport
I've found a certain French small car manufacturer has a subframe where all the bits happily Bolt on


Yes, given the performance/range parameters, you seem to be conceptually quite close to the Twizy. Seems the obvious thing to benchmark against?

I understand that in some Euro markets, they sell the battery pack outright rather than leasing it, too, which might be worth looking into.

Always worth looking for 'proof of the pudding'... the Twizy will show you the best that's realistically achievable with a small commuter EV, and similarly, the major manufacturers have spent huge amounts researching the optimum solutions for hybrids.

Suffice it to say that I don't know of any major manufacturer that uses a continuously running IC engine as a generator for electric drive; they're all PHEVs with IC range extenders that only kick in when the battery starts getting depleted, or IC direct drive, supported by electric (or vice versa).

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