# The best EV is in fact a electric hydraulic EV.. QED?



## Duncan (Dec 8, 2008)

If you are talking about very low speed machinery - 10 mph or less
Then you are quite correct!

At normal road speeds the losses in hydraulic systems rapidly get overwhelming


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## normanbutchgrant (Jul 20, 2016)

Hi Duncan... actually not at all limited to low speed. 

The research shows that even using a fully hydrostatic drive ( which is probably the worst case) that the results were significantly better than a pure EV... there is other work out there but the easiest is to look up is a guy "Jia-Shiun Chen" and his work... 

Basically the Electric Hydraulic version outperformed the pure EV in virtually every aspect? 

" The best electric vehicle is in fact a electric hydraulic vehicle" seems well reasoned

It also does not seem that difficult?


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## steveob (Nov 10, 2017)

it is always better to minimize brake usage, even with regen. For my driving style the difference would never pay for itself, even if it was dirt cheap.

Plus your figures are kind of random (hardly counts as adding "knowledge"), fwd regen can do a lot better than %30, 4wd even better. And the state of the art is constantly evolving.

Hydraulic regen isn't even specific to EV's. Plus it is tricky enough to make seamless transitions between regen and friction brakes already. You gonna add a bypass valve to control the hydraulic part? There goes all your efficiency. A wobble plate big enough to stop a car loaded with batteries (and a hydraulic tank and an accumulator)? Where you gonna put that stuff anyway?

Maybe if the post was less pretentious and more fact based.

not even a link to the "research" you are quoting...


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## Duncan (Dec 8, 2008)

So a hydraulic vehicle outperformed an EV?

As an engineer I find that very hard to believe - maybe it outperformed the EV that he built?

There are simply too may losses in a hydraulic system - and almost no losses in an electric system

The reason that you only get about a 10% range improvement from re-gen braking is NOT for the inefficiencies - it's over 80% efficient - but simply because there is very little energy going into the brakes - unless you drive like a hooligan

Do the numbers - calculate just how much energy you can store in a hydraulic accumulator - it's actually quite disappointing - enough for re-gen but not enough to actually drive somewhere

So you end up needing batteries and electric motors - the hydraulic drive then becomes just another parasitic load


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## normanbutchgrant (Jul 20, 2016)

Hi Steveob

I just did give some info on how to get some of the research data as a intro. I thought this would be quite a interesting discussion point for members to consider... 


I note your comments on my motive... but I take your point


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## normanbutchgrant (Jul 20, 2016)

hi again Duncan

The simulations in the research account for all the issues you mention and STILL "the best EV is a electric hydraulic EV" when the results are analysed. 

It may be simulations, but it is proper R&D

uhm... as a the engineer you state " almost no losses in an electrical system" is simply not true... The electric motor has a efficiency map ( not that different to hydraulic motor), then the inverter has a efficiency map and then the batteries (depending on the chemistry) have losses both with charge in and charge out. so no, it not true

I am trying to keep this a a lively debate for members too


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## steveob (Nov 10, 2017)

normanbutchgrant said:


> I thought this would be quite a interesting discussion point for members to consider...


If you find a torque/rpm vs efficiency graph for an existing motor (and additional plumbing and control), come talk to me, because there won't be anything to discuss if we just LOOK at the data.


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## normanbutchgrant (Jul 20, 2016)

wow...and you say I am pretentious...

I have done so... somehow I dont get how you cant disregard research that you could simply look up and confirm yourself instead of trivializing what is actually quite exciting developments in the field......

These are such obvious observations you ask me to redo and answer to you ....... wow again..... each and every point you have raised is dealt with if you would at least be open to look at the research 

( to misquote monty python " I can argue in my spare time")

Do you not think that proper R&D and published papers are worth at least 
looking at on your own time before making such authoritarian ( but wrong) comments


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## steveob (Nov 10, 2017)

You made a claim and refused to back it up. I'm not in the habit of validating every claim made on the internet, it is your responsibility to provide supporting evidence. I don't know what you are looking at even or how you drew your conclusions.

Yes, quite presumptuous of you to think I should "google it" when what you are saying doesn't make any sense.


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## normanbutchgrant (Jul 20, 2016)

well, that is your choice made... I trust other members may find more value in this discussion than you have.

yes, " The best EV is a electric hydraulic EV" ... based on proper research after all!


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## Duncan (Dec 8, 2008)

Ok
First have you done the energy calculations?

I will assume that you have and that you will understand that a hydraulic accumulator cannot replace the battery

So now I have two models 
One goes
Battery - source
Inverter - 95%
Motor -90%
direct drive - 98%
wheels
Overall - 84%

The other one goes
Battery - source
Inverter - 95%
Motor - 90%
hydraulic pump - 80%
Pipes - 96%
hydraulic motor - 80%
Direct drive - 98%
wheels
Overall - 51%

You simply can't get to the efficiencies of the electric model because the hydraulic bits are "extra" - additional conversion stages for the gods of thermodynamics to take their cut 


Now a hydraulic system on an IC engine can make sense - but on an EV it's simply not going to help 

Especially as the re-gen system on an EV uses no additional parts and has an overall efficiency 

wheels-
direct drive - 98% 
Motor -90%
Inverter - 95%
Battery - source

Overall efficiency 84%
The range improvement will vary from 15% to less than 5% - but that is simply due to the amount of braking that you need - and will be the same no matter what you use

You are simply NOT going to get any better than that - your hydraulic system is going to be worse


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## normanbutchgrant (Jul 20, 2016)

Hi Duncan, you really do misrepresent me and the research I allude to. Chen is a independent researcher.

Please just consider the potential value of what this thread. I am trying to promote what looks like a real paradigm shift that is not really difficult to implement either

research is research.. "like a box of chocolates, you never know what you gonna get"

for example, the Chen ( he is not the only one) research uses Matlab models that are proper physical models of engines, batteries , hydraulics etc and while his published research only plots against a few drive cycles, similar results are seen in virtually all other drive cycles. The Chen version is actaully not even a particularly good design yet even with that "the best EV is in fact a electric hydraulic EV"

are you really asserting that the Matlab models are unrealistic? 

this is actually quite exciting stuff


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## Duncan (Dec 8, 2008)

Yes 
I am saying that any model that adds some ADDITIONAL conversion stages - and purports to get better efficiency is by definition a load of bollocks!

Your Hydraulic EV still needs the
Battery
Inverter
Motor
Dive to wheels 

Those simply don't change 

Then you ADD -
Hydraulic Pump
Pipes
Hydraulic Motor

Every time you convert the gods take a cut!

You have NOT eliminated any of the existing inefficiencies

And you have ADDED three big ones

IC engines have large ranges of efficiencies - so you can sometimes get a benfit

But Inverters and electric motors do not have such a large range 
In the normal operation zone it is about 85% to 90% 

The only way that you could build a hydraulic EV with higher efficiency would be by comparing it to a normal EV that was being run miles outside the design parameters

I could build you a hydraulic EV that was more efficient at 4 mph than a Tesla at 4 mph
BUT only because the Tesla is not built to run at 4 mph

If you use any modeling software or system you should always do a sanity check on it -

I have often seen excellent expert systems give ludicrous results because the person using them has not understood how they were set up and has asked the system to do something that the original programmer did not think would ever be asked

Use modeling systems - but always be aware of GIGO - always do a sanity check


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## normanbutchgrant (Jul 20, 2016)

How do i state politely that you are simply wrong? I dont think there is a way..... I guess this whole thread will now be deleted as you have the admin buttons to do so.

I guess its time to state that I actually am heavily involved in this field and am very well suited to make the statements both from a theoretical and practical point ...

There are benefits in the regenerative braking and electrical optimization that will ( have) result in results predicted.....

ah well. I least i know I tried...

" So long, farewell, adeu adeu"


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## steveob (Nov 10, 2017)

zero knowledge to share, just a bunch of hearsay, thanks for absolutely nothing norman.

Given how improperly this was presented here, I have zero faith that there was "proper research" done in the first place.


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## normanbutchgrant (Jul 20, 2016)

well I think I need to thank Duncan for not doing the obvious and just deleting the thread....... was unexpected....

I am correct BTW... yes, I really am ........This is a one enabling technology for EV's and I am rather surprised at the direction this thread took... 

Anyway. If anyone else wants to continue this discussion, i will get the notifications and will try respond in a reasonable time


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## steveob (Nov 10, 2017)

I took your advice and googled relevant keywords.

https://www.angelcapitalmarket.com/investment-opportunity/hydraulic-hybrid-transmission-082716

so you are just trolling for "investors" in vaporware, basically selling.

Your opening title is empirically wrong, and you have offered zero empirical data to back it up, heck even suggesting you should is somehow "presumptuous", probably more gimmick to get people to "discuss".

buzz off. Or keep trying to get the last word and see where it goes till the thread gets locked.


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## normanbutchgrant (Jul 20, 2016)

steveob I have no idea who you are but you really need to get a grip on reality and what your technical limitations are.... ( Duncan, I really have no need for investors... FYI... we doing great thank you).

do you consider at all that maybe,........ just maybe, I am bring a really cool enabling technology to the group for discussion that i know about and you dont?...

Yip, that is what I am doing...


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## dh1 (Dec 21, 2015)

The Ariens Amp battery powered riding lawnmower was designed like that.
Battery powered electric motor driving a Hydrostatic transaxle.
It was total frailer, noisy, low power, short run time. 
Hydrostatic transaxle eats up to much power to run compared to a gear driven transaxle.
Basically they tried to use Hydraulic's as a speed controller, instead of a electronic motor speed controller which doesn't have the looses of Hydrostatic setup.


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## normanbutchgrant (Jul 20, 2016)

Gents, please at least try read the independent paper by Chen so that I can avoid any claims of bias ( or fishing!) by me... 

Things have advanced and this is a enabling tech for EV's that should be so enjoyed by those in the field. There are actual vehicles in various stages of development ...nuff said 

I/we dont need money

I/we dont need smarter engineers who can enlighten me of the errors of my/our ways ( you seriously cant!... certainly no one that replied so far).. Yes i am right and you are not.. It really is that simple....

I am really flabbergasted that a group like this is not watering at the teeth to see how EV's can be improved 

I think to show?maintain my credibility I am going to withdraw now and simply close my account and request the thread be deleted

wow... you really really amazed me... but yes, I think it is time to simply cancel the thread... Do I leave the request here Duncan? This has been a eye opener and a life lesson... "do not cast you pearls......"

Goodbye all


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## normanbutchgrant (Jul 20, 2016)

Duncan please close my account and close this thread.


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## electro wrks (Mar 5, 2012)

normanbutchgrant said:


> steveob I have no idea who you are but you really need to get a grip on reality and what your technical limitations are.... ( Duncan, I really have no need for investors... FYI... we doing great thank you).
> 
> do you consider at all that maybe,........ just maybe, I am bring a really cool enabling technology to the group for discussion that i know about and you dont?...
> 
> Yip, that is what I am doing...


I think you have something here. And, if you incorporate it with this, I think you could own/control the world:https://www.youtube.com/watch?v=Ac7G7xOG2Ag


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## brian_ (Feb 7, 2017)

Duncan said:


> The reason that you only get about a 10% range improvement from re-gen braking is NOT for the inefficiencies - it's over 80% efficient - but simply because there is very little energy going into the brakes - unless you drive like a hooligan


Excellent point, often missed in discussions of regenerative braking.


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> 1) the hydraulics can do regenerative braking at about 60% plus efficiency whereas a EV will be lucky to do 30%


This value, at least without some context to explain it, is nonsense. There is no reason for the combined efficiency of the motor (as generator), electronics, and battery charge acceptance to be only 30%.



normanbutchgrant said:


> So in town this is maybe a 30% range increase?


As already discussed, this is nonsense too, and doesn't follow at all from the previous statement. Perfect regeneration still results in no range increase unless the vehicle needs to brake.

While Norman is either a fraud or simply gullible, this sort of error frequently occurs in discussions of regenerative braking among people who just don't understand the reality of the situation.


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## normanbutchgrant (Jul 20, 2016)

excellent point you say? really? 

again no, simply not true..... 

common guys... this is not hard stuff....do the maths, do your home work...

1) unless you slow up the traffic, you have to actually drive with the traffic... so no, you cant simply decide what speed and acceleration you want.. Think it through guys.......that is why drive cycles exist to evaluate designs against, WITH all the flaws the cycles have...

2) no, regen braking on a electric vehicle is NOT 80% efficient. Dont make up facts that suit you.. .. you CANNOT charge the batteries at the rate that regen braking requires to meet a real drive cycle ( and No, using the service brakes is not the correct answer either, that just a straight loss... and No, the motor/inverter/battery chemistry cycle is NOT 80% wheel to wheel efficient... 

I will stop at that point but please, at least have the skill level to at least know how your systems are supposed to work...


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## MattsAwesomeStuff (Aug 10, 2017)

This nutjob is hoping that you'll delete his thread now that he's made a fool of himself and his "technology" that he refuses to discuss.

I say leave it up and quote his messages so that anyone who might get scammed has a chance of finding it.

Regen just isn't important to anyone unless you live in a mountainous area with hills so steep you're riding the brakes the whole way down. In normal stop and go traffic, very minimal gain. On highways, zero gain.

You're looking at what, 5% energy savings with perfect regen, in best normal driving situations? So that's the piece of the pie you're arguing over, 5%. Suppose electrical regen is "only" 30% efficient (which it's not)... 30% of 5% is 1.5%, *leaving only 3.5% possible max efficiency to be gained* by switching to some other system.

Take the cost of a battery pack. Take 3.5% of that. 

If you can add a hydraulic drive system with regen, with parts, installation, and service, and all the complexity it adds... for less than 3.5%, then I guess it's worth looking at. It won't be, not by miles, but that's the condition required for it to be worth looking at.

*Except that it's not, because this magical hydraulic system is a scam* and doesn't exist and is *less* efficient. It could only possibly cost more, not less.


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## normanbutchgrant (Jul 20, 2016)

I think I have to at least give you a chance to see the error...

Go evaluate a drive cycle.. ANY drive cycle you want... do the actualengineering work to see the basics... see what is rolling resistance, see what is aero losses, see what is braking ( and therefore a place to DO regen braking). 

There is no simpler way that i can suggest you evaluate your statements

seriously, you just wrong...... and I am right ..... again

At least have the ability to evaluate what you are saying


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> 1) unless you slow up the traffic, you have to actually drive with the traffic... so no, you cant simply decide what speed and acceleration you want.. Think it through guys.......that is why drive cycles exist to evaluate designs against, WITH all the flaws the cycles have...


True.

In my own driving (mostly urban), I would be astounded if even 10% of the energy produced by the engine is dissipated in braking, leaving less than 10% range improvement in an EV equivalent by perfect regeneration.



normanbutchgrant said:


> Go evaluate a drive cycle.. ANY drive cycle you want... do the actualengineering work to see the basics... see what is rolling resistance, see what is aero losses, see what is braking ( and therefore a place to DO regen braking).


In no reasonable cycle is there enough braking for even a perfect regeneration to extend driving range by 30% compared to no regeneration at all, yet the first post in this thread claimed 30% range extension by replacing electric regeneration (which has some effectiveness, whatever the number) with hydraulic regeneration (which certainly isn't perfect).

But hey, I don't have all the numbers readily at hand, so please provide a link to an analysis of a real driving cycle (not a simulation, MATLAB or otherwise) with the breakdown of energy destinations. I'm waiting on the edge of my seat.


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## normanbutchgrant (Jul 20, 2016)

No!!!! Please stop making up figures.....really just do your homework... in a city cycle, over 60% of the total cycle is "braking" energy... that INCLUDES engine braking, but that means where regen is possible

Even a Highway cycle has over 10%

Please dont guess.... here is a site that is independent and is really the very very basic maths

www.virtual-car.org

This is not hard stuff

Please just take the time to do the engineering instead of guessing


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> ... you CANNOT charge the batteries at the rate that regen braking requires to meet a real drive cycle ...


Even hybrids routinely regenerate at a sufficient rate to avoid use of the service brakes until a very low speed; battery-based "pure" EVs have even higher motor and battery power capacities, so sufficient regen rate doesn't look like a significant issue.



normanbutchgrant said:


> I will stop at that point but please...


If only that were true.


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> ... in a city cycle, over 60% of the total cycle is "braking" energy... that INCLUDES engine braking, but that means where regen is possible
> 
> Even a Highway cycle has over 10%
> 
> ...


The link is to an online tool for academic use, so I'm completely disinterested in the content. So, again...


brian_ said:


> But hey, I don't have all the numbers readily at hand, so please provide a link to an analysis of a *real driving cycle (not a simulation*, MATLAB or otherwise) with the breakdown of energy destinations.


Norman, please take the time to respond seriously, if you expect anyone to take the time to read your rants.


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## normanbutchgrant (Jul 20, 2016)

This is one of the first decent queries, please when you go to the independent site, just scratch around a bit

www.virtual-car.org

You can run against MANY drive cycles

Try the following: Find the area where you can "fiddle" the regen efficeciency ( use values of 0 ( normal car) 30% ( electric car BEST) and then just TRY my number of 60% for your own curiousity

THEN: look around for the carnot efficiency figure. I think the default is about 18% ( which accounts for part throttle losses).. PLAY with the number up to about the max possible of a IC engines ( something a bit of 30%)

I am suggesting that the regen proves my point?
I further suggest that fiddling with the Carnot number relates to the engine/motor optimization possibility that exists when you consider a system that CAN run the elctric motor system closer to its ideal LINE of operation at various speeds


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> This is one of the first decent queries, please when you go to the independent site, just scratch around a bit
> 
> www.virtual-car.org...


Again,


brian_ said:


> ... please provide a link to an analysis of a *real driving cycle (not a simulation*, MATLAB or otherwise) with the breakdown of energy destinations.


Norman, are you having trouble with the difference between real data and simulation results? If there is real data on that site, just link to it.


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## normanbutchgrant (Jul 20, 2016)

Brian that site is a "toy" and far far from hardcore engineering. There can hardly be anything more basic and user friendly. At least look at it

there are numerous studies by DOD and Boston University ( I Think?) comparing electrical hybrids to hydraulic hybrids that will show the wheel to wheel regen braking comparison that prove my point over many studies

I am using in dependant information


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## normanbutchgrant (Jul 20, 2016)

Brian, if you really need to say " if only that were true", then just stop the questions ... It wont change facts.


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> Brian, if you really need to say " if only that were true", then just stop the questions ... It wont change facts.


I don't think you understood the comment, Norman. I meant that you say that you're done posting, but that is clearly not true.

If you post crap, you should expect challenges.


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## normanbutchgrant (Jul 20, 2016)

Brian, lets get a few lines on the ground... Hybrids have been tested with figures by DOD and are not "just simulations" and they have many studies showing the benefits and comparisons of EV and hydraulics hybrids in various forms. 

I dont think the numbers they publish are in dispute?

SO.... the point of my discussion is that there is a whole body of research saying that actually combining electric and hydraulic actually may be a darn good idea. It really not that much of a stretch

Chen who is just one of the guys has used reasonable engineering across a WIDE range of hybrids and came up with what to him was a unexpected result... EV are best with hydraulics EVEN though his actual design is pretty "average" 

this info really should be of interest to a group like this...


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## steveob (Nov 10, 2017)

so, like I said,
when you have an efficiency heatmap for all torque and rpm, as a motor and a generator, for the system as a whole, and it is independently reproduce able (not by your cousin or whatever) then you might have some actual facts to work with, and the thing will sell itself. There is no sound engineering in starting with a simulated "drive cycle", too many places to cheat. That is the stuff of politics/marketing, like the rest of your posts.

Oh, you have all the investment money you need, AND YOU HAVEN'T BUILT ONE?!?! You are the one who said it wasn't difficult. Again vaporware. Given how sloppy you are with words here, there is zero chance you have sufficiently simulated reality. But that doesn't stop you from thinking you have, or trying to market your idea.



normanbutchgrant said:


> " The best electric vehicle is in fact a electric hydraulic vehicle" seems well reasoned
> 
> It also does not seem that difficult?


so, go ahead, build the one true best EV, like that sort of claim hasn't been made before or something, every single day.

what a sham. Just because you think something, doesn't make it real, especially when there is financial incentive and bias. Fortunately the rest of us don't seem quite so handicapped, and have higher standards of proof.

You can of course save SOME face by retracting your claim and regaining at least some appearance of integrity. Otherwise you should quit now.


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> Brian that site is a "toy" and far far from hardcore engineering. There can hardly be anything more basic and user friendly. At least look at it


No. If it is a toy, that's even more reason to ignore it. You assert what you say are facts, and refuse to provide a source. 

I don't need a kiddie tool; I am interested in data.



normanbutchgrant said:


> there are numerous studies by DOD and Boston University ( I Think?) comparing electrical hybrids to hydraulic hybrids that will show the wheel to wheel regen braking comparison that prove my point over many studies
> 
> I am using in dependant information


Claiming that "there are numerous studies by DOD and Boston University" without providing actual sources is just classic scam behaviour.

If I state that "there are numerous studies by DOE and MIT that show less than 1% of power produced by a car's engine is dissipated by braking in an urban environment" that is just as valid as your statement... even though my example is complete fiction and factually incorrect.


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> ... Hybrids have been tested with figures by DOD and are not "just simulations" and they have many studies showing the benefits and comparisons of EV and hydraulics hybrids in various forms.
> 
> I dont think the numbers they publish are in dispute?


What numbers? Please link to them, because as unknown numbers not given in the discussion, they certainly are in dispute.


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## normanbutchgrant (Jul 20, 2016)

steveob, you actually have no idea what i have done or am doing...... why do you care enough to reply... you have made your point for all to see

you are wrong..... again


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## major (Apr 4, 2008)

normanbutchgrant said:


> ... in a city cycle, over 60% of the total cycle is "braking" energy... that INCLUDES engine braking, but that means where regen is possible ...


Hmmm. 60% energy braking! Leaves 40% of total cycle energy for acceleration and propulsion. That doesn't sound possible unless you start each cycle at a much higher elevation.

major


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## normanbutchgrant (Jul 20, 2016)

Duncan, your choice to leave this thread or not, but simply put, this should have been a interesting technical discussion.

but yes, I am the one who is right... the whole time, every time.

Goodbye all.


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## normanbutchgrant (Jul 20, 2016)

Major please.......it does not matter what you think... please just do the engineering... it has very little to do with elevation

That is the facts.....


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## steveob (Nov 10, 2017)

normanbutchgrant said:


> Major please.......it does not matter what you think... please just do the engineering... it has very little to do with elevation
> 
> That is the facts.....


Major has made a valid point, and that is your response? maybe you should re-read your assertions. Sounds like you have made a HUGE error in your calculations if it stands as read. My guess is that your calculations are full of errors.


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## MattsAwesomeStuff (Aug 10, 2017)

> Go evaluate a drive cycle.. ANY drive cycle you want... do the actualengineering work to see the basics... see what is rolling resistance, see what is aero losses, see what is braking ( and therefore a place to DO regen braking).


Look, you're either a scammer, or you've been taken in by one.

But this conversation has merit for the people who find this interesting, or who might be misled. So, sure, I'll humor you.

Would you like to go first and provide some facts that you're basing those statements on? Of course not, you've been unable to give any facts at all when people have asked. That's okay, I'll go first.

http://www.enginuitysystems.com/EVCalculator.htm <-- Let's use this calculator.

For every 1000kg of vehicle (a light vehicle), to accelerate that object to highway speeds (100km/h or 60mph) requires 107 watt-hours. For city driving (50km/h or 30mph) it requires 26 watt-hours.

But maybe you're into conspiracies, and you don't trust that calculator. Okay, no problem.

Kinetic energy = Mass * Speed * Speed / 2

100 km/hr (60mph) is 27 meters/second.
50 km/hr (30mph) is 14 meters/second.

So the kinetic energy in watthours (3600 joules per watt-hour) to accelerate 1000kg up to city or highway speeds is:

City: 27 watt-hours.
Highway: 101 watt-hours.

Right on target.

Every time you stop, the maximum amount of energy you can recover, is that amount, because that's the only energy you put into your momentum. And that's if you don't coast or ease up on the brake, that's instant stopping 100% loss.

Let's look at the Nissan Leaf, which has a 24,000 watt-hour pack.

That means you can accelerate to city speeds and then slam on the brakes at lights, wasting all of your energy, no coasting, 889 times on that pack. Or at highway speeds (how often are you reaching highway speeds and then braking to full stops?), 237 times.

The measured city range of a Nissan Leaf is 70 miles at highway speeds, 140 miles at city speeds.

How many times within 140 miles are you stopping?

https://youtu.be/KnOwWyUsJlE?t=299 <-- Here's a little graph that shows a breakdown of the energy available for regen versus the energy used in driving.

When you're driving at highway speeds and take your foot off the gas, how fast does your vehicle slow down? Boom, 20% of your speed is gone in a couple seconds without any braking. That's not energy you'd be recovering. Most of the energy that goes into stopping, is consumed by traveling the distance you need to travel to stop under reasonable forces. It's very close to the energy lost to coasting. Especially at the top end. Towards the bottom end you can coast for a long time, but there's hardly any energy left at that point (just that the wind resistance is similarly so small).

I think 5% is a reasonable number. 10% if you're an aggressive driver who accelerates up to full speed when you see vehicles in front of you already hitting their brakes.

Empirically, this is in line with everyone's real-world measurements too.

So, go ahead, pick those numbers apart. And then show how much better hydraulics could be, and how much extra they'd cost.

But we both know you won't, because you can't, because you don't have any supporting facts. You'll just repeat endless circular conversation about how important regen is. Go ahead, prove us all wrong, use some facts.


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## normanbutchgrant (Jul 20, 2016)

Steveob, do you understand that the energy used in a drive cycle comes from the prime mover? ( that converts either fuel or charge to energy of course) 

I will assume "yes" and continue...

So in the case of a internal combustion engine, the energy has at some point come from the engine burning fuel at some relative efficiency that changes according to speed, throttle setting mainly. 

In the most simple form, that energy is used in a drive cycle and the MAIN sinks of that energy is rolling resistance, Aero resistance and braking (including engine braking). 

Ignoring engine efficiency and part load effects, CLEARLY at low speed, city cycle has USED that energy mainly to accelerate and slow down as the wind resistance is obviously lower. When you break the energy into the three sinks above, in town, the Braking one is well over 50% closer to 60%...

basic Newton F=ma stuff

and similarly at highway speeds, the aerodynamic losses start to dominate.

So the energy has come from fuel ( or batteries, the same principle applies) NOT height

of COURSE a drive in a hilly area has a effect, but ANY height energy is limited to the hill you started on..


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## steveob (Nov 10, 2017)

normanbutchgrant said:


> steveob, you actually have no idea what i have done or am doing...


because you don't appear to have actually done anything and won't say anything but "google it". And it is fun watching you flounder trying to defend your imaginary position with nothing to back it up and dig the hole deeper for thinking we are the idiots here just waiting for norman to show us the light.


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## brian_ (Feb 7, 2017)

major said:


> Hmmm. 60% energy braking! Leaves 40% of total cycle energy for acceleration and propulsion. That doesn't sound possible unless you start each cycle at a much higher elevation.


I think the intention was that of the energy produced by the engine (not fuel input to the engine), 40% is dissipated to overcome mechanical losses, rolling drag, aerodynamic drag, and accessory loads, leaving 60% used to accelerate the vehicle. All of that 60% of the drive energy which becomes kinetic energy of the moving vehicle is then dissipated during deceleration, and so potentially available for recovery through regenerative braking.

That all makes sense, and I have no problem with it... except that this would be stop-and-go traffic, and probably with a significant speed change (e.g. accelerate hard to 60 km/h, brake hard immediately, accelerate hard again...). It's not a realistic driving scenario for me, although some are stuck doing this in their commute. It certainly isn't an overall average for a typical private passenger vehicle.

For a reasonableness check, consider that this sort of driving means heavy fuel consumption and most of the engine output is going to the brakes, which means a lot of brake heat. If (for instance) you are averaging 15 L/100km, and 50 km/h average, that's 7.5 L/h. At 34 MJ/L, that's 255 MJ/h. If the engine is 20% efficient, that's 52 MJ/h of engine output and 60% of that is 30 MJ/h to the brakes, or 9 kW. Are the brakes of a compact car in this (severe) condition as hot as they would be with 9 kW being fed to them continuously? Seems high to me, but perhaps.


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## normanbutchgrant (Jul 20, 2016)

Matt, you really need to rethink your maths and pysics

yes F=ma, but you got F wrong in terms of its components

you are making a trivial mistake that i have dealt with in other posts.

NO... the energy in a drive cycle is NOT only acceleration like you are calculating. You are certainly not humouring me... you are wrong and I am right

The MAIN energy sinks ( I dot intend to got into all of them) is rolling resistance, aero resistance and acceleration ( where braking is considered negative acceleration)

No I am right, you are wrong...


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## steveob (Nov 10, 2017)

brian_ said:


> except that this would be stop-and-go traffic, and probably with a significant speed change


which is basically what duncan was getting at in post number 2, and why they have real world hydraulic hybrid examples on things like garbage trucks and busses. (plus the extra weight helps w/regen, but not anything else).


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## MattsAwesomeStuff (Aug 10, 2017)

normanbutchgrant said:


> ... in a city cycle, over 60% of the total cycle is "braking" energy


A fascinating discovery. A magical land. *You live in a city that driving is downhill both ways!*

How is 60% of your energy used in braking? 60% is more than 50%. If you're using 60% of your energy braking, where is the energy coming from that you're wasting??

You're using 1.5x the energy to stop the vehicle than you have put into making the vehicle moving. It's a perpetual motion machine! Endless stopping energy!

I'm kind of joking around because this is ridiculous. In all seriousness, at times like this it's important to remember than some people suffer from mental health issues, sometimes diagnosed, and that this is what life is like for them


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## normanbutchgrant (Jul 20, 2016)

to setveob... what a strange reply to a engineering question.. I am not floundering in the least... the reply to you is trivial and basic 

I am right, you are wrong


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## steveob (Nov 10, 2017)

normanbutchgrant said:


> I am right, you are wrong


you imagine you are right, and have failed miserably to demonstrate it. I feel bad for your investors if this is your marketing plan.


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## normanbutchgrant (Jul 20, 2016)

Matt, If you really think I have said the city is downhill in both directions, i have no cure for that answer....

I am right, you are wrong


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## steveob (Nov 10, 2017)

normanbutchgrant said:


> I am right, you are wrong


So far, everyone here is wrong besides you... I wonder if you can even HAVE a discussion about this thing rationally.


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## normanbutchgrant (Jul 20, 2016)

yes... I am right... 

Brian has asked some decent question that I have tried to give independent answers to

Yup... you got it


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## steveob (Nov 10, 2017)

well, given that you have zero evidence, and are marketing some vaporware, and don't show sound engineering (or language), or even bother to back up your claims? what now? 

Move this trash fire of a thread to "for sale"?


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## MattsAwesomeStuff (Aug 10, 2017)

> The MAIN energy sinks ( I dot intend to got into all of them) is rolling resistance, aero resistance and acceleration ( where braking is considered negative acceleration)


You are correct in this statement, but this statement provides evidence **against** your claims.

The only energy that regenerative braking can recover is momentum. From a heavy object moving with a certain speed, that needs to come to a stop.

The energy that is spent in rolling resistance (heating up the tires and the road as they deform) and acceleration (pushing the air out of the way) cannot be recovered by any form of regenerative braking. It's gone into heat and momentum of the air throughout your entire trip.

For example:

Let's say you're in a Nissan Leaf. You get on the highway and you drive all the way until your battery pack is empty, no stopping.

You start with 24,000 watt-hours.

A Nissan Leaf weighs 1500kg.

To accelerate the leaf to highway speeds, then requires 151 watt-hours.

So now you have 24,000 - 151 = *23,849 watt-hours* left.

The Nissan Leaf uses 342 watt-hours per mile, and thus the battery runs out 70 miles down the road.

At this point the car still has the original 151 watt-hours of momentum.

If you hit the mechanical brakes, you'd waste this last 151 watt-hours as heat in the brake discs. But if you hit the regen instead, you'd have 151 watt-hours left in the battery. 0.6% of the battery life. But you say that electric regen is only 30% efficient. Okay, so, with electric regen you'd have only 50 watt-hours saved, but there's a possible 100 watt-hours lost, maybe a more efficient system could recover that.

Or, you could coast, perhaps as much as 1 additional mile. (Likely a combination of the two).

You could add thousands of dollars of hydraulic equipment to this, if you think your system is so much better than existing regens. Or, you could just add an additional 100 watt-hours to your pack. Even at single-cell rates, let's say $5 for an 18650 that holds 10 watt-hours... *you're saving a grand total max of $50*.

Your hydraulic system is perfect, no losses, and can be installed parts and labor for under $50?

That's your argument.

Or maybe you mean traveling at city speeds? Then you're going 140 miles, and only have 18 watt-hours wasted by existing regen. *About $20.* TWENTY BUCKS!

Go on, show me your magical hydraulic system that's perfectly regenerative that you build for less than $20 if that's your argument.


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## steveob (Nov 10, 2017)

Matt, to norman you are just some unspecified drive cycle, and probably aren't worth his time to give actual evidence of his claims. He wants people to "google for it" and hopes that in isolation he may find some more suckers.


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## normanbutchgrant (Jul 20, 2016)

(This reply is not directed to steve...)

gents, IF you put some clever hydraulics on a EV (meaning ' The best EV is a EV with some hydraulics".... that does some cool things like better regen and some motor optimization), you get a better EV... You already all are fans of EV, thats why you are here i assume...

I really do not know why this has angered so many.. whew.

I am not looking for investors, I am not looking for engineers... This was meant to be some cool tech for you to know about and chat

To the forum, this has not been fun. I have NOTHING to gain nor do I need anything from anyone here. I think this has come to a end... 

If you dont like the idea, so be it, I have done my bit to share

.. If you see some merit, i guess this is where it ends for all of us in this forum

Bye


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## steveob (Nov 10, 2017)

(this reply is directed at norman)
provide evidence of your claims or go away. You can't even define "best" in this context.


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## MattsAwesomeStuff (Aug 10, 2017)

Be nice guys! You're gonna scare him away!

I want to hear about his $20-$50 hydraulic regen system. I wanna put one on an electric skateboard I'm building.


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## Duncan (Dec 8, 2008)

Hi Norman
Your problem is that you have landed in a bunch of cynical people who are either engineers or are otherwise technically savvy - and have actually built things

They will not be taken in by appeals to authority or wild claims about simulations

Best to try somewhere else if you want mindless approval or investers


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## MattsAwesomeStuff (Aug 10, 2017)

> you have landed in a bunch of *cynical* people


"Skeptical" would perhaps be more accurate, though, with all the free energy claimers, "cynical" ain't a bad fit either


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## brian_ (Feb 7, 2017)

MattsAwesomeStuff said:


> How is 60% of your energy used in braking? 60% is more than 50%. If you're using 60% of your energy braking, where is the energy coming from that you're wasting??
> 
> You're using 1.5x the energy to stop the vehicle than you have put into making the vehicle moving. It's a perpetual motion machine! Endless stopping energy!


Well, no. As I posted earlier:


brian_ said:


> I think the intention was that of the energy produced by the engine (not fuel input to the engine), 40% is dissipated to overcome mechanical losses, rolling drag, aerodynamic drag, and accessory loads, leaving 60% used to accelerate the vehicle. All of that 60% of the drive energy which becomes kinetic energy of the moving vehicle is then dissipated in braking, and so potentially available for recovery through regenerative braking.


That earlier post goes into more detail, and challenges the reasonableness of the value, but the key is that this "60%" (or whatever the correct value might be for a given driving scenario) is not *in addition to* energy put into acceleration, it *is* the energy put into acceleration.

As already noted by others, much of the kinetic energy of the moving vehicle cannot be recovered (to the battery or hydraulic energy store) even by perfectly efficient regenerative braking, because energy is still used to move the vehicle (against drag) during the braking period.


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## brian_ (Feb 7, 2017)

normanbutchgrant said:


> gents, IF you put some clever hydraulics on a EV (meaning ' The best EV is a EV with some hydraulics".... that does some cool things like better regen and some motor optimization), you get a better EV... You already all are fans of EV, thats why you are here i assume...
> 
> I really do not know why this has angered so many.. whew.


It is true the that members of this forum will be fans of EVs, although some may be only interested in EVs. So yes, most would be interested in any way to improve an EV, although some will be hostile to anything that is not electric. Some will oppose anything with an engine, and may similarly oppose other types of energy storage and transmission systems (hydraulic, electric, flywheel); however, I don't think that's the reason for any of the concerns expressed so far in this discussion.

The issue is that the superiority of a design has been claimed, arrogantly and loudly, without sound basis. What's really missing is objective data to support an inherently complex solution to an inherently simple problem. Even without the objective data, the forum's response would probably be more supportive if the idea were presented for discussion, rather than as a declaration which should not be challenged.


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## KevinTheGriff (Mar 29, 2018)

First post and on a touchy topic....here goes.

I think this is the document that Norman is referring too
http://www.mdpi.com/1996-1073/8/6/4697

To be honest, most of it was way over my head. But there maybe something in it that's been overlooked upto now?
Kevin


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## Duncan (Dec 8, 2008)

Hi Kevin

OK now that paper makes some sense
BUT its not an EV with hydraulic drive
It's an IC engine with a hydraulic hybrid system for recovering braking energy

This is old technology - I remember it from the 70's - and in some circumstances it can be as efficient as a normal Hybrid

But Norman was taling about an EV - a completely different animal

OK I have read the whole paper

This is a prime example of "Reductio ad Absurdum"
You use your assumptions to show a stupid answer - which shows that your assumptions were wrong

In this case he uses his model to show that adding extra losses increases the efficiency!

Which simply shows that his model was wrong in the first place!


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## ishiwgao (May 5, 2011)

Duncan said:


> This is a prime example of "Reductio ad Absurdum"
> You use your assumptions to show a stupid answer - which shows that your assumptions were wrong
> 
> In this case he uses his model to show that adding extra losses increases the efficiency!
> ...


*off-topic* I have learnt a valuable english (and history) lesson today by googling "Reductio ad Absurdum". 

Have always been doing this in school many years ago, but never knew there was such a term for it.


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## steveob (Nov 10, 2017)

read it, norm was wrong.


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## brian_ (Feb 7, 2017)

KevinTheGriff said:


> I think this is the document that Norman is referring too
> http://www.mdpi.com/1996-1073/8/6/4697
> 
> To be honest, most of it was way over my head. But there maybe something in it that's been overlooked upto now?


Interesting source:
Energies is self-described as a "journal", but is a collection of articles for which the authors have paid for "processing" (publication), without peer review.

With zero innovative ideas for component selection or design, the only thing which could have been overlooked is the possibility of using both electric and hydraulic systems together, and indeed that appears to be the original poster's point: "there is a better way". Unfortunately, article is far from presenting a convincing argument.

*The Good*

The article provides a decently illustrated overview of the various hybrid configurations.
It clearly shows its source data for factors such as motor efficiency and driving cycle conditions.

*The Bad*

It bases its conclusions entirely on simulation results, and fails to provide any empirical validation. For instance, the author didn't even enter the parameters of any existing EV into the simulation to confirm that the simulated result matches actual performance.
The driving cycle used in the simulation is the New European Driving Cycle, which consists largely of the Urban Driving Cycle, which is extreme stop-and-go. The UDC portion executes 12 cycles of moving then returning to a complete stop in only 780 seconds - about once per minute.
The consequences of system complexity are essentially ignored - a small mass penalty is assumed, but that's it.


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## brian_ (Feb 7, 2017)

Duncan said:


> BUT its not an EV with hydraulic drive
> It's an IC engine with a hydraulic hybrid system for recovering braking energy
> ...
> But Norman was taling about an EV - a completely different animal


No, the "HEHV" is an EV/hydraulic parallel hybrid, with no (IC) engine; see Table 1 and section 2.12. The electric machine (motor-generator) and hydraulic machine (motor-pump) and mounted the same drive shaft (they're parallel), and there is no other power source. The hydraulic system is used to capture energy in regenerative braking and return it during low-speed operation. My understanding is that Norman is suggesting this configuration, although he calls it an "electric hydraulic EV".


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## Duncan (Dec 8, 2008)

Yes I did get that when I read though the whole thing

So he has added a completely unnecessary pump/motor accumulator - which will do exactly the same job as the electrical bits that are already there at LOWER efficiency not to mention the drag and losses when the thing is in normal - non re-gen mode

What does he hope to gain?

The only way that increases efficiency is if he chooses low efficiency bits for the electric side


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## brian_ (Feb 7, 2017)

Duncan said:


> So he has added a completely unnecessary pump/motor accumulator - which will do exactly the same job as the electrical bits that are already there at LOWER efficiency not to mention the drag and losses when the thing is in normal - non re-gen mode
> 
> What does he hope to gain?
> 
> The only way that increases efficiency is if he chooses low efficiency bits for the electric side


The relevant conclusion of Chen's study is that:


> The performance comparison of the EV and HEHV revealed that the HEHV exhibited 23.38% higher electricity conservation compared with the EV in the UDC primarily because the hydraulic assist system prevented the electric motor from operating in the low-efficiency region (72%) during low-speed operations.


... so he is assuming higher efficiency of the hydraulic system in a specific range of conditions. This is the motor use optimization that Norman mentioned.

It does seem like a lot of extra hardware, and there is no experimental validation of the simulations, let alone this conclusion.


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## Duncan (Dec 8, 2008)

So a higher efficiency then the electric motor in a small part of the cycle yielded a 24% improvement!

As a low efficiency zone for a motor gets down to about 65% that would imply a 90% efficiency for the pump/motor accumulator - which is simply bollocks!


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## steveob (Nov 10, 2017)

I think he is hoping we will comb over it all to find the magic solution for him so he can sell his stuff easier once he realized it was a stupid idea. something he "overlooked"...

which is also bollocks.


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## brian_ (Feb 7, 2017)

Duncan said:


> So a higher efficiency then the electric motor in a small part of the cycle yielded a 24% improvement!
> 
> As a low efficiency zone for a motor gets down to about 65% that would imply a 90% efficiency for the pump/motor accumulator - which is simply bollocks!


It does sound unreasonable, but I'm just not going to wade through all of the input data to see where there are likely problems. The author or other proponent needs to validate the input data and model before it is worth our time... or at least mine.


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## Duncan (Dec 8, 2008)

brian_ said:


> It does sound unreasonable, but I'm just not going to wade through all of the input data to see where there are likely problems. The author or other proponent needs to validate the input data and model before it is worth our time... or at least mine.


That is what you do - when your model gives silly answers you look for the problem!

You know that there is a problem because the answer is not sensible 

But it's not up to us to do that problem shooting - that is what Chen? should be doing


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## steveob (Nov 10, 2017)

well norm is the one with financial incentive, not sure chen was a willing participant in this marketing scheme.

In any event, anyone who has spent more than 2 minutes on energy density would realize this is a non-starter. Sure, give up 3/4 of your battery storage for next to nothing on regen, great idea.


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## brian_ (Feb 7, 2017)

steveob said:


> ... not sure chen was a willing participant in this marketing scheme.


Regardless of what Chen's paper is being used to promote, the work itself is lacking in validation and so is not really worth publishing. I'm not saying that he should have built an electric-hydraulic parallel hybrid, just that he should have validated the model against existing real vehicles of those configurations which do exist... at least the most simple, which would be an EV, and preferably enough vehicles to cover each type of equipment (so any one of the configurations with a hydraulic component).



steveob said:


> In any event, anyone who has spent more than 2 minutes on energy density would realize this is a non-starter. Sure, give up 3/4 of your battery storage for next to nothing on regen, great idea.


I'll admit to having spent no more than 2 minutes (before typing this), but the density of energy storage in a fluid-filled chamber seems problematic. 

See section 2.5.2 for Chen's hydraulic energy storage model, which included an 18 litre accumulator (change in hydraulic fluid volume) cycling from 172 bar (17.2 MPa, 2495 PSI) to 344 bar (34.4 MPa, 4989 PSI). It's a significant chunk of hardware (and there's also the pump-motor, low-pressure side accumulator, plumbing, and controls), but a relatively small energy store as it is only for the energy available from regenerative braking in a single stop.

The energy storage requirement for the accumulator was based on braking from only 60 km/h (to suit the urban cycle), which corresponds to 208 kJ of energy (of course less will actually be captured). The 208 kJ is correct; I didn't check if the 18L accumulator cycled between those pressures stores that amount of energy. Yes, that's only 59 Wh... the accumulator is terribly heavy and bulky for the energy, but the energy requirement is tiny. Gasoline-electric hybrids typically use a much larger energy store, by an order of magnitude.


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## Duncan (Dec 8, 2008)

brian_ said:


> The 208 kJ is correct; I didn't check if the 18L accumulator cycled between those pressures stores that amount of energy. Yes, that's only 59 Wh... the accumulator is terribly heavy and bulky for the energy, but the energy requirement is tiny. Gasoline-electric hybrids typically use a much larger energy store, by an order of magnitude.




_by an order of magnitude_

Try at LEAST *two* orders of magnitude!


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## brian_ (Feb 7, 2017)

Duncan said:


> _by an order of magnitude_
> 
> Try at LEAST *two* orders of magnitude!


Yes, I suppose that two orders of magnitude is closer... but not "at least", since only a plug-in hybrid would have more than 6 kWh of battery (let alone ten times more), and this is a non-plug-in scenario.


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## rayacox (Dec 19, 2012)

To improve Electric regenerative braking, a bank of ultracapacitor or supercapacitor would help absorb such a large electric energy surge. A little expensive but lite in weight and no messy liquids. I'm making an assumption the battiries slower charge rate is why mechanical braking is used for quicker stops.


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## Emyr (Oct 27, 2016)

This thread could have been resolved a whole load faster had Norm just linked to this "amazing" "research" in the first post.


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## brian_ (Feb 7, 2017)

rayacox said:


> To improve Electric regenerative braking, a bank of ultracapacitor or supercapacitor would help absorb such a large electric energy surge. A little expensive but lite in weight and no messy liquids.


Managing both a battery and a supercapacitor bank (even if you could buy a useful one for a reasonable price) would add complication that would be hard to justify... just as the hydraulic system of the "electric hydraulic EV" would be hard to justify. At least the capacitors wouldn't add mechanically complexity.



rayacox said:


> I'm making an assumption the battiries slower charge rate is why mechanical braking is used for quicker stops.


While battery charge rate can limit regenerative braking rate, I don't think it's the major concern. Published graphs showing regenerative and friction braking from manufacturers such as Nissan indicate that regenerative braking is limited at very low speeds (due to motor characteristics). Also, most EVs are two-wheel-drive, and for balance some braking at the other axle is normally desired (this is likely one reason that Tesla regenerates less than some others: 2WD Teslas are rear-drive, while most EVs are front-drive, and you want to brake primarily with the front tires).


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## Duncan (Dec 8, 2008)

rayacox said:


> To improve Electric regenerative braking, a bank of ultracapacitor or supercapacitor would help absorb such a large electric energy surge. A little expensive but lite in weight and no messy liquids. I'm making an assumption the battiries slower charge rate is why mechanical braking is used for quicker stops.


Hi Ray
The reason that re-gen is not used at high levels is because there is very little to gain

As a general rule people do a lot of "slowing down" - so we use re-gen for that - and it is more than adequate

BUT there is kind of a gap between that and the next level of braking which is the "accident avoidance" or even "emergency stop" braking

At the "emergency stop" levels stopping is all important - which means that you really want your main hydraulics doing the work and NOT being interfered with by another seperate system

The amount of extra energy that can be recovered by increasing the re-gen levels is simply not worth it as people just don't brake in the hard braking zone very often 
And when they do they want to stop - not recover energy


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## brian_ (Feb 7, 2017)

Duncan said:


> Hi Ray
> The reason that re-gen is not used at high levels is because there is very little to gain
> ...
> The amount of extra energy that can be recovered by increasing the re-gen levels is simply not worth it as people just don't brake in the hard braking zone very often...


Excellent perspective.


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## nucleus (May 18, 2012)

Duncan said:


> So you end up needing batteries and electric motors - the hydraulic drive then becomes just another parasitic load


Sometimes a thought experiment will get you there. It is impossible that another energy conversion in the chain will increase the conversion losses.


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## brian_ (Feb 7, 2017)

Duncan said:


> So you end up needing batteries and electric motors - the hydraulic drive then becomes just another parasitic load


True - since the hydraulic pump-motor is spinning all of the time, the drag to turn it when it is doing nothing is a parasitic load.



nucleus said:


> It is impossible that another energy conversion in the chain will increase the conversion losses.


Huh ?
Another energy conversion in a chain will definitely increase conversion loss, so perhaps either there's a typo in there or it was intended sarcastically. In any case, the proposed configuration (which wasn't clear until very far into the discussion) has the electric and hydraulic systems in parallel, so there is no extra energy conversion step.


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