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  #11  
Old 05-15-2012, 04:43 PM
TigerNut TigerNut is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

Quote:
Originally Posted by lkcl View Post
again, please! what's with the assumptions! i've *thought* about this. the rear wheels will be in air-sculpted compartments that give the rear of the vehicle a more "standard-car-like" visual aspect as well as helping recombine the airstream. the front is a little trickier because i'm limited by the size of the suspension springs of the suzuki - i'll do my best to make the air gaps as large as possible whilst also maintaining sculpted compartments [i should have thought about this - the size of the suspension springs - before buying the suzuki, and gone for the aixam straight away, but it was too late. ah well]

the bodywork's actually effectively double-skinned: even the doors will have a double skin, with the air gap varying from 8 inch to *18* inch (at the rear) right down the entire sides of the car. this is all part of the patent.



i've thought of this. it's why the bodywork expands *outwards* at the elbows, and back in again at the waist. nobody drives with their elbows straight down! [i drive with my elbows out sideways, so the door's design will accommodate that] it's very... figure-hugging shall we say. i'm 6ft1 so i will definitely make sure that people slightly taller than i am can get in it! any wider than me... well, there are a couple of local farmers whom i want to see, just for a laugh, if they'll be able to fit
I'm just going by what you posted on your webpage... I see renderings of an open-wheel car with fairings over the wheels, but not much in the way of suspension detail. Nothing that suggests Cd calculations either by simulation or wind tunnel model, other than your note that you're going to somehow hit 0.3.

Since you're going for mass appeal, you should try to find virtual mannequins that represent 90th percentile folks, and make sure that both the short and tall ends of that range can fit in your car rendering. I'm not sure about elbow orientation... I drive with my hands at 3 and 9 o'clock on the wheel and that naturally puts my elbows not much more than shoulder-width apart.
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  #12  
Old 05-16-2012, 03:43 AM
Duncan Duncan is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

Hi Ikcl

You keep rabbiting about your patent, either you have applied in which case the details are public domain or you have not applied yet

If you have applied let us know - it's already public domain
Of not - get weaving and don't even hint on the web
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  #13  
Old 05-16-2012, 04:44 AM
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

Interesting concept. I was a member of a discussion group that was proposing a similar concept. I think I found it here, but it has not been very active lately. The perpetrator was trying to produce a 100 MPG vehicle for $5000 or so, and he was rather rigid in his belief system so he had a hard time accepting constructive criticism:
http://autos.groups.yahoo.com/group/...iencyvehicles/

For your project I have just a few ideas to toss in:

(1) See if a 3-phase induction motor or BLDC will be more efficient, less expensive, more rugged, and easier to control than your series wound DC machine.

(2) Add a heat pump to convert waste heat to cabin heating and reverse it for A/C.

(3) Use ultracaps for fast charge and discharge for regen braking and short term acceleration.

Best of luck on your project. The biggest hurdles will be public acceptance, and making driving in general safer for everyone by eliminating ICE road rage and aggressive driving.

Also, if a vehicle such as yours could be sort of folded up so that it could be taken as luggage on a train, then people could use that form of mass transit which would reduce traffic and highway maintenance and allow people to relax and enjoy their commutes and long-distance trips rather than wasting time and being subjected to stress and danger.
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  #14  
Old 05-16-2012, 07:55 AM
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

So you're pretty much making one of these (Red Bull X2010, pic attached), then?

Chris
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  #15  
Old 05-17-2012, 01:02 PM
lkcl lkcl is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

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Originally Posted by PStechPaul View Post
Interesting concept. I was a member of a discussion group that was proposing a similar concept. I think I found it here, but it has not been very active lately. The perpetrator was trying to produce a 100 MPG vehicle for $5000 or so, and he was rather rigid in his belief system so he had a hard time accepting constructive criticism:
http://autos.groups.yahoo.com/group/...iencyvehicles/
oh dear! did he give actual reasonable justifications? also, i have to say: 100mpg isn't a particularly challenging target! the Aixam and Ligier vehicles get 100mpg, and the Aixam NICE "City Car", although it only has one gear (i.e. no gearbox to speak of) so is a top speed of 40mph (gosh, shock, horror) it still does the equivalent of 140mpg no problem. but, *again*, those little "Quad-bike" cars, they're all 2.0sqm (ok maybe less - maybe 1.5sqm), Cd of 0.3 (or thereabouts) so *again* they're not... yeah

Quote:
For your project I have just a few ideas to toss in:
appreciated - let me try to be "reasonable", then, eh?

Quote:
(1) See if a 3-phase induction motor or BLDC will be more efficient, less expensive, more rugged, and easier to control than your series wound DC machine.
ah. right. yes. i originally looked at BLDC motors. going by prices on e.g. kellycontrollers.com, there's the MARS 0913 i think it is, 10kW, and $600, then there's another one which is rated at 14kW, it's something insane like $1000. the price jump is just... unacceptable, *plus* they're only 90% efficient! that PMG226 is, amazingly, 94% or something close to it.

also, again, the controllers: richard's 4QD 200amp controller, 250; kellycontroller's matching controllers for their motors: $600? $800? i forget how much.

the only thing that does have me concerned is that by picking a lower voltage motor (PMG226 is 48v) i now have to find *small* batteries that will do 200 to 300 amps. that's going to be tricky _but_... hey, it's a prototype.

bottom line is: prototype and production are very different: i'm not keen on brushless motors, but finding a decent low-cost (small and low weight) 12 to 15kW BLDC motor, with an efficiency over 94%? tricky... if this was 30kW or greater then yes, it would *have* to be BLDC...


Quote:

(2) Add a heat pump to convert waste heat to cabin heating and reverse it for A/C.
interesting... i like this. what i was going to do, was this: the PMG226 needs quite a bit of cooling in order to operate without burn-out at low RPMs. i am an extremely jammy git: it turns out that there's an impeller in the suzuki, used for the heating system. so, i was just going to pump the airflow that goes through the motor directly into the cabin.

however... i really like the heat pump idea - thank you


Quote:
(3) Use ultracaps for fast charge and discharge for regen braking and short term acceleration.
ah... NO have you seen the cost? they're f*****g insane amounts of money. i spoke to a company in germany that manufactures them. basically, for the same weight (and cost) as batteries, you get ONE TENTH of the storage capacity (but ten times the current handling).

[btw richard's 4QD controller is an H-Bridge, so does regen braking: i was just going to keep the batteries within 20-80% charge, and what the heck, just treat them as a replaceable item. as this is lead-acid and only a 2.5kWh set of cells not an insane 80kWh high-explosive bloody dangerous and expensive rare-earth lithium battery pack, i'd say that treating a small lead-acid set of cells as a replaceable item is reasonable]

also, as ultra-capacitors are, duh, capacitors, the voltage obviously drops off in a standard decay curve, meaning that the electronics required to generate a stable voltage for the motor is a bit... horrendous.

this problem is one of things that has delayed the RiverSimple car [also a Category L7e heavy quadricycle]: they were having enormous difficulties getting the electronics sorted, having to operate at 400v, things were a little unstable.

the other problem was that they specified direct drive motors, but if you do some basic math, the weight of the vehicle+passengers (550kg) vs gravity on say a 25% gradient requires EIGHTY kW... just to overcome gravity. the limit on Category L7e vehicles is 15kW. whoops.

Quote:
Best of luck on your project. The biggest hurdles will be public acceptance, and making driving in general safer for everyone by eliminating ICE road rage and aggressive driving.
thank you well... yes. funny isn't it. do you _want_ to feel so in control that you have the means to threaten people with death just because _you_ didn't see them step into the road??

if ever you've driven in china or india, it's so incredibly different. i skated *against* the flow of traffic on bangalore's airport road - people just moved out the way - no horns blown at all! mind you, it helped that i was wearing orange (apparently it's some sort of recognised buddhist thing that people wearing orange equals buddhist, who are known in india for "exploring that space, maaan" - so if you do something insane like skate against the traffic on a busy road, they just go "ahh, there goes a buddhist" and get out the way!)

china, again: utterly different. i saw an old lady in a huge sedan, completely ignoring all traffic signs (presumably because she couldn't actually see them). rather than honk like mad, everyone *slowed down* and just went round her.

when people stepped into the road, or even if they were just standing at the edge, people honked their horns to say "hey! we're here! please pay attention for your own safety!". by contrast, in europe and the U.S., people only honk their horn when it's almost *too late*, to tell people to "GET OUT of *MY* way." they use the horn to indicate that inconvenience has occurred *to them*.

fascinating difference.

anyway, yes: what i'm counting on is the much lower cost of the production vehicle, and the much-reduced running costs and maintenance costs, to overcome any intransigence or subconscious rage.

Quote:
Also, if a vehicle such as yours could be sort of folded up so that it could be taken as luggage on a train, then people could use that form of mass transit which would reduce traffic and highway maintenance and allow people to relax and enjoy their commutes and long-distance trips rather than wasting time and being subjected to stress and danger.
now that _is_ an interesting idea. unfortunately it won't be this vehicle: it'll be about 350kg. a portable vehicle would have to be somewhere around... 40kg, maybe 60kg absolute maximum if its wheels could fold up to become trolley-like wheels. that's quite a serious engineering challenge, let alone an Aerodynamics one. i do like it, though, enough to plug it into my socially-challenged brain, see what comes out in a few months, eh?

thanks paul.

/peace.
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  #16  
Old 05-17-2012, 01:10 PM
lkcl lkcl is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

TomA, hi, many many thanks for the "jig" idea. having cut out the rear suspension entirely in once piece, i'm going to actually weld the replacement frame directly onto that and *then* remove the old one, piece by piece. actually what i'm going to do is a mock-up out of wooden sticks, first

http://lkcl.net/ev/suzuki_swift_conversion/IMG_0088.JPG
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  #17  
Old 05-17-2012, 01:13 PM
lkcl lkcl is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

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Originally Posted by iti_uk View Post
So you're pretty much making one of these (Red Bull X2010, pic attached), then?

Chris
AYE! :} ok, take one of those, then put it into a 2nd "skin" that makes it look vaguely look like an average "hot hatch" supermini.

ah... on second thoughts... no those racing cars have some insane Cd like 0.7 which they use to make the car stick to the road like glue. nutters.
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  #18  
Old 05-17-2012, 08:33 PM
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Quote:
Originally Posted by lkcl View Post
oh dear! did he give actual reasonable justifications? also, i have to say: 100mpg isn't a particularly challenging target! the Aixam and Ligier vehicles get 100mpg, and the Aixam NICE "City Car", although it only has one gear (i.e. no gearbox to speak of) so is a top speed of 40mph (gosh, shock, horror) it still does the equivalent of 140mpg no problem. but, *again*, those little "Quad-bike" cars, they're all 2.0sqm (ok maybe less - maybe 1.5sqm), Cd of 0.3 (or thereabouts) so *again* they're not... yeah
Here is the original group and the mission statement:
http://autos.groups.yahoo.com/group/...cientVehicles/

And the new one:
http://autos.groups.yahoo.com/group/...s/message/1027

Here are some archives of my posts in the old forum:
http://www.enginuitysystems.com/files/SEV.txt

I have many other files, mostly on EVs and Hybrids and electric motors, from around 2006. Some may be helpful:
http://www.enginuitysystems.com/files/
[/quote]

Quote:
bottom line is: prototype and production are very different: i'm not keen on brushless motors, but finding a decent low-cost (small and low weight) 12 to 15kW BLDC motor, with an efficiency over 94%? tricky... if this was 30kW or greater then yes, it would *have* to be BLDC...
Actually I think AC induction motors are the best all-around. And I have built an inexpensive DC-DC converter so I have been able to run a small riding mower using a 240V 2HP 3 phase motor and a single 17 A-H SLA battery. I think the most efficient and safest system may be a module consisting of 1 to 4 lead-acid batteries with an integral DC-DC unit and charger, with regen and overload protection and monitoring (perhaps with CANBUS or USB). They could be series and/or paralleled on the secondary side with 320 and 640 VDC which would be instantaneously shut down as needed. The high currents would be contained in the battery modules, which could be made to be modular and hot-swappable, and the car could limp along on only one pack if necessary.

Quote:
interesting... i like this. what i was going to do, was this: the PMG226 needs quite a bit of cooling in order to operate without burn-out at low RPMs. i am an extremely jammy git: it turns out that there's an impeller in the suzuki, used for the heating system. so, i was just going to pump the airflow that goes through the motor directly into the cabin.

however... i really like the heat pump idea - thank you
I think some hybrids use that idea.

Quote:
ah... NO have you seen the cost? they're f*****g insane amounts of money. i spoke to a company in germany that manufactures them. basically, for the same weight (and cost) as batteries, you get ONE TENTH of the storage capacity (but ten times the current handling).

[btw richard's 4QD controller is an H-Bridge, so does regen braking: i was just going to keep the batteries within 20-80% charge, and what the heck, just treat them as a replaceable item. as this is lead-acid and only a 2.5kWh set of cells not an insane 80kWh high-explosive bloody dangerous and expensive rare-earth lithium battery pack, i'd say that treating a small lead-acid set of cells as a replaceable item is reasonable]

also, as ultra-capacitors are, duh, capacitors, the voltage obviously drops off in a standard decay curve, meaning that the electronics required to generate a stable voltage for the motor is a bit... horrendous.
A regulated PWM DC-DC converter (such as is in standard computer supplies, after the initial rectifier and filter), can easily handle 120 to 370 VDC and produce a regulated 12 VDC (or whatever you design it for).

Quote:
this problem is one of things that has delayed the RiverSimple car [also a Category L7e heavy quadricycle]: they were having enormous difficulties getting the electronics sorted, having to operate at 400v, things were a little unstable.

the other problem was that they specified direct drive motors, but if you do some basic math, the weight of the vehicle+passengers (550kg) vs gravity on say a 25% gradient requires EIGHTY kW... just to overcome gravity. the limit on Category L7e vehicles is 15kW. whoops.
That's why I contend that at least a two speed transmission be used. It could be a reduction drive for slow speed torque, and a straight-through for highway speeds at maximum efficiency.

Quote:
now that _is_ an interesting idea. unfortunately it won't be this vehicle: it'll be about 350kg. a portable vehicle would have to be somewhere around... 40kg, maybe 60kg absolute maximum if its wheels could fold up to become trolley-like wheels. that's quite a serious engineering challenge, let alone an aerodynamics one. i do like it, though, enough to plug it into my socially-challenged brain, see what comes out in a few months, eh?

thanks paul.

/peace.
Actually, I did not mean a truly portable vehicle like a bicycle which can be carried by one person, but a lightweight vehicle about the weight of a large motorcycle, but designed to open up to be a 2-4 passenger lightweight car, or folded into a compact form that could be lugged around on its own wheels and fit into a baggage car. The do have the "auto train" where you can have your car shipped to your destination on a flatcar while you ride in a railway coach, but it's rather expensive. If an EV could fit in a baggage car with dozen others, and be able to be charged by the train (especially during downhill braking, rather than burning off the energy as is often done on long steep descents), it will be more affordable and efficient.

Thanks for the kind discussion. Good luck!
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  #19  
Old 05-17-2012, 09:38 PM
TomA TomA is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

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Originally Posted by lkcl View Post
TomA, hi, many many thanks for the "jig" idea. having cut out the rear suspension entirely in once piece, i'm going to actually weld the replacement frame directly onto that and *then* remove the old one, piece by piece. actually what i'm going to do is a mock-up out of wooden sticks, first

http://lkcl.net/ev/suzuki_swift_conversion/IMG_0088.JPG
Yikes, that's bold!

I think that will be OK to learn on, but you've cut up the floor pretty severely, and you're going to need to make sure it doesn't warp or twist when you attach your jig. This is hard (impossible) to do, because welding the jig will tend to stretch the whole thing around as the metal heats and cools while you are making it.

Next time, just flip the whole unibody onto its roof and put the jig together on the new topside where its easier to work. You can always level the jig later on the ground, using the measurements you took before you lightened the chassis. (Relax, its OK if don't have them. Just find a car like yours on the road and measure that...)

Love the sticks! Good start, you're getting the idea.

Be sure to make the mounting plates first, making sure each is the same shape and hole pattern as what actually bolts to the chassis, and do really bolt them all in place with any shims, washers and such you took off with the old parts. Then you can start connecting all the attachment plates together with the jig steel, using the unibody's strength to hold the jig accurately. Then you cut the jig and weld on alignment plates to reassemble only as necessary to get it off the unibody.

When you do take it off, see if any of the plates pull away from or push on their mounts as you unbolt it. You'll probably need to beat the jig up with a hand sledge a little to be sure it really just rests on the unibody and is precisely the right dimension everywhere. Then, be super careful with it to avoid tweaking it out of dimension before you fab the replacement frame on it. You'll know what I mean when you get there.

There are plenty of more advanced ways to fab up a chassis, but this is a good one for the inexperienced. Teaches you to weld better, too.

Really love the sticks...

Last edited by TomA; 05-17-2012 at 09:42 PM.
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  #20  
Old 05-23-2012, 03:30 PM
lkcl lkcl is offline
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Default Re: Ultra-efficient Hybrid EV Conversion started (Category L7E)

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Originally Posted by TomA View Post
Yikes, that's bold!
*cackles*
Quote:
I think that will be OK to learn on, but you've cut up the floor pretty severely, and you're going to need to make sure it doesn't warp or twist when you attach your jig. This is hard (impossible) to do, because welding the jig will tend to stretch the whole thing around as the metal heats and cools while you are making it.
hmmmm...
Quote:
Next time, just flip the whole unibody onto its roof and put the jig together on the new topside where its easier to work. You can always level the jig later on the ground, using the measurements you took before you lightened the chassis. (Relax, its OK if don't have them. Just find a car like yours on the road and measure that...)
yes - got one of those. thank god. i've done the rear suspension already: actually cutting it out in one piece, then putting replacement struts in place was a bitch, but it's done.
Quote:
Love the sticks!
ha ha, yes so do i. i'm staring at the front suspension and the little drawing i did, and, just as i did before doing the rear part, had absolutely no clue where to put any struts. bits of wood and tape, 3 hours later it was "ok! right! yes. metal goes here, here and here".

http://lkcl.net/ev/suzuki_swift_conversion/IMG_0130.JPG

so, this one's not entirely clear (took it front-on) will do a better one tomorrow, but the diagonal bits (on the floor, underneath) reaching towards the front and narrowing to a point will a) be part of the nose (base) b) help support the gearbox c) provide a 3rd point for a tripod to support the top of the front suspension.

the nice thing about the suzuki swift gearbox is that it's only 13in wide (and 21kg), suupperrrb gearbox. with an 8in pancake motor the whole front nose needs only be 24 to 26in wide. assuming the vehicle's 4ft8 wide and the wheels are 6in that leaves a whopping 9in wide airgap (minimum) between the front wheels and the bonnet [at the rear it's a similar story, only bigger: the gap at the back could go as wide as 15in].
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