Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-26-2013, 08:30 PM   #31 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 692
Thanks: 371
Thanked 227 Times in 140 Posts
Quote:
Originally Posted by RedDevil View Post
So, P&Ging does help me overcome the Insights inefficiency at the low revs&low load combination.
Just as P&G can help and be a + ... when it is able to increase the average efficiency of the ICE more so than the non-P&G average ICE efficiency would have been at the same average speed ... with a bit more additional ICE efficiency gains needed to over come the aerodynamic penalties for the speed fluctuation of the P&G.

Quote:
Originally Posted by RedDevil View Post
P&G at highway speeds is useless in the G2.
Principles are the same ... fast , slow , or any speed.

% variation causes the same % of aerodynamic penalty at any driving speeds.

The increased difficulty many P&G users run into at faster speeds ... is how much more ICE efficiency can be gained at higher average speeds and higher average loads ... there are limits ... the ICE has a best case max efficiency.

If the ICE steady state is already operating at peak ICE efficiency ... the only way to improve MPG is by improving the ratio of ICE efficiency and energy consumption ... ie reduce the consumption more than you reduce the ICE efficiency... some of that can be smarter driving ... or just driving at a slower average speed.

You can't see a net MPG gain , if the P&G extra aerodynamic penalty is equal or larger than any remaining possible gain in ICE average efficiency for the same average speed.

Quote:
Originally Posted by RedDevil View Post
if you first drain the battery the FE when the ICE finally kicks in is not.
Just like P&G there are + and - aspects with the HEV system.

It is not a + all the time used in any method ... neither is P&G.

The right tool for the right task.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-27-2013, 09:07 AM   #32 (permalink)
Master EcoWalker
 
RedDevil's Avatar
 
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,998

Red Devil - '11 Honda Insight Elegance
Team Honda
90 day: 47.72 mpg (US)
Thanks: 1,711
Thanked 2,245 Times in 1,454 Posts
The limits on the G2's efficiency at low speed are both physical and functional. The RPM is lower at the same tpeed than with the G1, and the CVT will keep the revs at 1100 no matter how slow you go. When that happens the FE drops linear with the speed. Unless you can P&G.

At low speed air resistance is way less than at high speed, and so is the penalty for changing speed.
So I see no problem in my P&Ging at low speed. I get good mileage, even though the last 4 months were colder than average for the time of year. P&G plays just a minor role in that, but if you look at my record you will clearly see the point where I learned to reduce the use of the hybrid system.

It is great to use the EV mode when the battery is full, so if you can charge it by the mains or charge on coast where you'd need to brake otherwise, that is the best you can do. As you said, it will always depend on circumstances.
Trying to keep the battery full will make the system use it whenever it can, while if you draw it empty it will try to replenish it given half the chance.
If you want to stay in control you need to anticipate the chances you will get to draw or load; e.g. draw it empty before going down that mountain and keep it brimmed before going up.
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.


For confirmation go to people just like you.
For education go to people unlike yourself.

Last edited by RedDevil; 04-27-2013 at 09:35 AM..
  Reply With Quote
Old 04-27-2013, 10:18 AM   #33 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 692
Thanks: 371
Thanked 227 Times in 140 Posts
Quote:
Originally Posted by RedDevil View Post
The limits on the G2's efficiency at low speed are both physical and functional. The RPM is lower at the same tpeed than with the G1, and the CVT will keep the revs at 1100 no matter how slow you go.
It is the change in ICE efficiency ( weather or not RPM changes at all ) that has the ability to give a net +MPG even with the penalty P&G always gives to energy cost at the same average speed.

Quote:
Originally Posted by RedDevil View Post
At low speed air resistance is way less than at high speed, and so is the penalty for changing speed.
The Penalty is still there ... always there ... the principles are still the same at any speed ... the act of P&G has to result in some other part of the system ( like the ICE ) improving more than the act of P&G itself gives you that penalty... there has to be a bigger + somewhere than the P&G gives a - , in order for it to be a net +.

Quote:
Originally Posted by RedDevil View Post
So I see no problem in my P&Ging at low speed.
Neither do I ... I never meant to indicate that I did.

Nor do I see a problem with anyone P&Ging ... it's their drive they can drive it anyway they like ... and if their goal is to travel the same distance at the same average speed while consuming less gallons to do it ... sometimes P&G will help them ... other times it will hurt them.

I think it is ultimately better for them to understand how and why it helps and how and why it hurts ... that way they are more able to make the best choice for a given set of conditions.

Quote:
Originally Posted by RedDevil View Post
if you look at my record you will clearly see the point where I learned to reduce the use of the hybrid system.
That is the kind of over generalized one sided suggestion I disagree with.
For multiple reasons ... as touched on previously.

Quote:
Originally Posted by RedDevil View Post
As you said, it will always depend on circumstances.
Yes that part I agree with ... it is a known and tested fact.

It is how I myself prefer to tell people about HEV system use and P&G use.
  Reply With Quote
Old 07-23-2013, 11:17 AM   #34 (permalink)
Master EcoWalker
 
RedDevil's Avatar
 
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,998

Red Devil - '11 Honda Insight Elegance
Team Honda
90 day: 47.72 mpg (US)
Thanks: 1,711
Thanked 2,245 Times in 1,454 Posts
... with some extra batteries?

I am considering to turn my Insight into a mild PHEV by adding some 1 kWh op LiFe(Y)PO4 (Lithium Iron Phosphate or LFP) batteries and stuff. Charge that at home, gently (all but) deplete on the move, to aid acceleration and to allow for P&(e)G-ing on the highway. Every time I can put 1 kWh into my commute it should save me at least half a liter of fuel, so it has the potential to save me over € 200 each year just on commutes.

The idea is to feed the IMA system with 500-1000 W continuously once power is engaged, maybe making it voltage-dependent to feed more into it when the system needs it and maybe even charge back a bit under braking.

Maybe could add some thin foil solar cells on the roof later, if the setup works fine.

The batteries have to be LiFePO4 or LiFeYPO4 type as those seem ideal for this kind of use. But I haven't looked into how to feed the IMA yet. Any tips?

Maybe I can compensate for some of the extra weight by exchanging the under hood lead acid battery for a smaller LiFePO4 battery.
Then it shoud not have a BMS system as that interferes with the high current draw while starting, but I wonder if I can safely do so. If the battery gets charged at over 14.4 V (3.6V per cell), then I guess not.
If it (the lead acid battery) gets charged at less than 12.8 v then the LFP wouldn't get charged at all.

Of course I could use a small BMSed LPF battery and a string of supercaps to circumvent these issues. But I just wanted to keep it simple.

So... what would be my chances to make this successful?
Should I create a low-amp high-voltage pack slightly over the IMA's operating voltage and just bleed it in?
Or should I use a DC-DC converter, controller and stuff?
Or is this all just a bad idea?
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.


For confirmation go to people just like you.
For education go to people unlike yourself.
  Reply With Quote
Old 07-23-2013, 06:58 PM   #35 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 692
Thanks: 371
Thanked 227 Times in 140 Posts
Quote:
Originally Posted by RedDevil View Post
So... what would be my chances to make this successful?
Sense I've known people who have done this kind of thing ... one form or another ... I'd say it's just a question of if the amount of personal investment ... time and such ... is worth it to you ... I have zero doubt about weather you have the ability to make it happen.

Quote:
Originally Posted by RedDevil View Post
Should I create a low-amp high-voltage pack slightly over the IMA's operating voltage and just bleed it in?
Or should I use a DC-DC converter, controller and stuff?
Or is this all just a bad idea?
All of those and others are all options ... all with their pros and cons , for you to weigh out and make a personal choice on.

Grid Charging the OEM NiMH is fairly limited ... but people do , do it... and it is the least complex ... least expensive ... and easiest.

Grid charging 2 or more OEM NiMH packs in parallel ... gives more capacity... still fairly easy , and fairly low cost.

Using a dedicated booster battery to 'bleed' in replacement current ... can be done with either the DC-DC from a lower Voltage booster pack ... or with some other current limiting controller from a higher voltage pack... it does add in the complexity and conversion efficiency hits for the electronics ... but if done well ... those can be very very small hits... this is the 3rd level of more complexity and cost ... but also tends to be the 3rd level of PHEV potential gains.

Some people just upgrade / replace the OEM IMA NiMH with a more modern ... more energy dense battery pack ... it means fooling the OEM BCM , and having your own BMS , and Charging system ... but it does allow for the most kwh per kg of HEV battery in the car ... for example ... the Swap people do in the Gen-1 Insight to A123 20Ah pouch cells gives about 3 to 4 times more energy than the Old OEM NiMH ... without adding any weight to the car... this tends to be the most complicated and most expensive ... although it has been done / proven.

No matter what ... have fun with it.
  Reply With Quote
Old 07-24-2013, 04:41 AM   #36 (permalink)
Master EcoWalker
 
RedDevil's Avatar
 
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,998

Red Devil - '11 Honda Insight Elegance
Team Honda
90 day: 47.72 mpg (US)
Thanks: 1,711
Thanked 2,245 Times in 1,454 Posts
Thanks. Swapping the NiMH pack for LFP's (like the A123 cells) would indeed be best FE wise, but I still got warranty on my good NiMH pack.
I suspected it to be lazy by infrequent use in its first year, but it did really surprise me going up and down the mountains in Germany; the meter stayed fat in the blue zone for minutes on end going uphill. The MID showed a fuel usage of less than 8 l/100km for that stretch, while my ears popped.

My aim now is for the long string of batteries to hook into the pack on contact.
I will look into that charge/discharge limiter to prevent the individual BMSes from kicking in.
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.


For confirmation go to people just like you.
For education go to people unlike yourself.
  Reply With Quote
Old 07-24-2013, 05:16 AM   #37 (permalink)
Master EcoModder
 
IamIan's Avatar
 
Join Date: Dec 2010
Location: RI
Posts: 692
Thanks: 371
Thanked 227 Times in 140 Posts
Quote:
Originally Posted by RedDevil View Post
My aim now is for the long string of batteries to hook into the pack on contact.
I will look into that charge/discharge limiter to prevent the individual BMSes from kicking in.
Best of luck ... just a few notes , you probably are already aware of.

Plan for the system to handle peak possible inrush current / power rates ... Although the packs change as they age , temperature, SoC/SoE , etc ... if you design for the end points of max and min , you will be best set.

AFAIK , the minimum net resistance for the whole OEM IMA NiMH pack all cells and connections is ~360mOhms ... V=IR ... the minimum OEM IMA NiMH pack voltage is ~120V ... the Max is ~187V.

So you can use those and the min max specs on the booster battery you are planning to connect , to get a reasonable prediction of the direction of peak current / power flow ... and the magnitude.

Then you will be in a good position to be able to either plan for / design the charge/discharge limiter you mention ... and/or ... chose when in what situations to use it.

Best of luck.
  Reply With Quote
Old 07-24-2013, 05:34 AM   #38 (permalink)
Master EcoWalker
 
RedDevil's Avatar
 
Join Date: Dec 2012
Location: Nieuwegein, the Netherlands
Posts: 3,998

Red Devil - '11 Honda Insight Elegance
Team Honda
90 day: 47.72 mpg (US)
Thanks: 1,711
Thanked 2,245 Times in 1,454 Posts
Thanks. I believe those numbers are for the gen1 pack though, the gen2 has a lower voltage pack.
And I will regulate max current both ways, And put an amps meter on that I can read behind the wheel.
I't like to keep the voltage somewhere within the operating range, so that it recharges under braking. This way it will lower the hysteresis loss e.g. raise the charge/draw efficiency. But it need be on the high side or it would stay full and not be able to take much grid or solar charging.

__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.


For confirmation go to people just like you.
For education go to people unlike yourself.
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com