How hard to you push from 0 to 60

<div class='quotetop'>QUOTE(theorist @ Nov 1 2006, 01:56 PM) [snapback]342063[/snapback]</div>

Y'know, I have to admit that I'm only now getting up to speed on the nuances of the HSD...and I don't own a ScanGauge or anything like that, either. Interesting...I'm still getting a mental picture of how all of this hardware and software comes together. There's a lot of theory that still seems to apply, but a lot doesn't anymore.

I really like the way you said it: "The idea is that the battery is used to keep the engine load in the efficient zone. If the demands are too high, the car will feed the battery; too high and the car will draw from the battery. Either avoids engine inefficiency but incurs battery losses."

Helps me to understand why it's best to see no arrows going anywhere when the MFD is displaying energy flow.

I think, on a theoretical level, the deal with pumping losses is that WOT *does* help minimize them, but only at constant RPM's...not under hard acceleration. I was taught that it's best to run the smallest displacement engine appropriate for the job, at as close to WOT as possible, while keeping it in the thick part of the powerband.

Seems to me that the HSD does, indeed, help make this happen...I *love* this car!!!

 

Hmm... an interesting thread.
I always thought that getting the ICE to power the car AND feed the battery was the target.
Then, once the battery had enough SOC in it to go stealth, you do.
I have had the same commute for 20 years pretty much and there are stretches of road that I know I can go P&G trying to use stealth as much as possible, other parts I can use EV until the SOC is down to 2 bars.
So I try to build up the SOC for stealthing those particular stretches.
I used to hate lorries and trucks but now I tuck in behind the slower ones so I can keep stealthing until SOC is so low the ICE kicks in.

In another old PC thread, I learnt that over 56mph consumption goes up proportionally to the speed you do over 56 mph - basically the faster you go the more you consume.
So 0-60 is an exception for me - rather than the rule.

 

<div class='quotetop'>QUOTE(pinball @ Nov 7 2006, 06:03 PM) [snapback]344882[/snapback]</div>

It is not a good idea to use the battery down to 2 bars.
The ideal P&G is not to use the battery power shown below...
http://hybridcars.about.com/od/ownership/a/pulseandglide.htm

Ken@Japan

 

Thanks Ken,
I find that the 'no arrows' state is very brief for me - all that really happens is that the car's mph drops more slowly than it would if I took my foot off the pedal altogether.
I end up slowing the traffic flow and people on my tail - the upside is I have a nice clear view in front of me :lol:
In order to keep a steady speed I have alternate between battery and ICE.
But I didn't think no arrows was true P&G though - I had always understood you Pulse on ICE and Glide on battery (arrows all the time).
I've read the article link and will try to put 'no arrows' into practice better.
Cheers

 

anytime you use the battery, you are getting way less power out than what was put in. conversion losses are pretty large. knowing this, the best thing is not to use the battery and run the ICE in only the efficient range right?

well, the ICE simply cant do that, so the battery helps in the time that the ICE cant run at its best. it also provides extra power when needed. that is the key. determining when this extra power is needed. so accelerating at a pace just below the point when charge starts being sent to the battery is the objective.

the battery should be charged but only when on a downhill, slowing down to keep pace with traffic or when anticipating traffic signals and conditions, etc.

granted this is a tough thing to do and tougher when traffic is heavy AND if you are very very good at the anticipation thing, eventually the battery will charge no matter what. but that is the thrill of the 60 mpg tank. you know it happened after a sustained period of discipline, skill, and luck. iow, the same characteristics of any successful venture.

 

Thanks for those tips Dave. I shall try on my way home this evening.
I have a 3 mile stretch at 50 mph limit right outside our building, which I do on ICE
At the end of the stretch I have a full battery (but not green)
At this point I go into P&G (with arrows) until ICE kicks in around 4-5 bars or because I have to go faster or die.
Sometimes if there's no traffic I slow to 30mph and use EV till 2 bars then ICE kicks in and I start over, using the next stretch to recharge the battery.
Using this tactic and EV wherever I possibly could, my best tank was 68.7mpUKg.
I'm not sure of the maths to US gallons but I think its about 57mpUSg.
At any rate, if I can improve on that it would be f a n t a s t i c

Thanks

 

believe me, there is a LOT of room for improvement, the hypermilers have already proved that. sure they did it under extreme conditions, but there are everyday people here doing 60+ mpg and you can too.

that is what i love about this car. the challenges are almost unlimited. my goal is 63 mpg, and 675 miles on a tank...

why?? did 62 mpg and 660 miles...that which was a fantasy dream no longer excites me... been there, done that... now, its the next higher rung

 

I've been trying to reach the no arrows state more often than before and although I'm a little better at it now what I've found so far is this :-
Once I get to the no arrows state and a certain speed, say 35mph, I cannot sustain the same speed for more than a few yards or seconds - I have to press the gas pedal a mere fraction ( of a fraction ) to keep 35 mph and when I do I immediately get arrows drawing power from the battery - but at least I can keep my mph.
Where am I going wrong ? - or is this how its meant to be ?

I don't suppose US and European models work differently perhaps ?

Re the EV mode - I've found that EV will let me run entirely on battery until 2 bars - then some fail-safe mode kicks in and starts the ICE. I figure that because this is a setting that Toyota builds in must be OK to drop down to the 2 bar level.

 

<div class='quotetop'>QUOTE(pinball @ Nov 9 2006, 07:18 AM) [snapback]346151[/snapback]</div>

No arrows is hard to do and really not possible with terrain that is hilly. It is also a waste of time. I try to keep arrows charging the battery. This keeps it in a higher charge state and therefore more efficient when you do need it. The car is always charging and discharging and the no arrows are just a window with fairly low charge and discharge currents.

Discharging to the max is not good since you then lose control to the car. I generally use electric mode a lot but stay in the 4 to 6 bar range. If you go all the way down to 2 bars the battery becomes less efficient and also you have no control when it charges. You don't want to sit at a red light with engine on just to recharge the battery.

I have hills where I live and generally charge going up hills and run stealth down hills. This works best for me. If I try to stay ev going up hills I wind up with a discharged battery or a too cold engine and it winds up running going down hills.

Max mpg is always from running engine when you need power and not running it when power need is low.
Further gains possible with pulse and glide but negligble for me (due to terrain) and impractical in any traffic.

 

<div class='quotetop'>QUOTE(pinball @ Nov 9 2006, 07:18 AM) [snapback]346151[/snapback]</div>

Using pulse and glide, you will not generally maintain a constant speed. If you want to maintain a constant speed, use the battery. Pulse and glide technique stores and draws energy in kinetic energy rather than the battery.

It sounds like your Prius is decelerating faster than mine when gliding (no arrows). Your Prius probably uses tires with higher rolling resistance than most in north america. I've equipped mine with LRR Continental ContiProContacts inflated to 48-46 psi. I live near Tom and rarely encounter long stretches of perfectly flat road. I'll often glide down very gentle 2km inclines with no arrows. On a flat dry road, the car will glide from 65kmh to 40kmh over nearly one km.

Pulse and glide is not easy. If it was, everyone would use it. We should all stay considerate to other drivers and put safety over fuel consumption. An accident can instantaneously outweigh any possible savings from hypermiling.

Toyota won't let you draw the battery down below a 40% state of charge or charge it above 80% so that the battery might last more than a couple years. If the NiMH cells in a Prius are like others, they would only be expected to last several hundred full depth charge cycles. A driver trying to use the battery from full to empty and back again several times each day could easily need a new hybrid battery pack within a year, especially with the assistance of an EV mode that would let them nearly drain the battery completely. By not allowing the battery to discharge below 40% or charge above 80%, Toyota is able to make the battery last much longer. In fact, the ECU tries to keep the SOC between 50% and 70% most of the time. It seems Toyota only really wants us to use a fifth of the battery capacity.


http://privatenrg.com/index.55.jpg

 

Thanks fellas - most enlightening

 

<div class='quotetop'>QUOTE(SomervillePrius @ Nov 1 2006, 08:09 AM) [snapback]341906[/snapback]</div>

Good explanation, I can deal with the visual feedback on the display... I'm not sure yet where 3/4 throttle is, exactly.

During my brief commute to the train there are several sections where I can get up to 35 mph using just the electric motor - all yellow arrows on the display. If there's no reason to rush, of course.

Braking regenerates the battery, though - I'm confused on the idea that this is lost energy.

 

<div class='quotetop'>QUOTE(DocVijay @ Sep 15 2006, 10:26 PM) [snapback]320352[/snapback]</div>

Hugh?? I thought I read on some thread here that 1/3 throtle 'till you reach optimum pulse/glide speed achieved best mpg results. I DO note that flooring it really sucks the mpg WAY down.

 

<div class='quotetop'>QUOTE(pinball @ Nov 9 2006, 09:18 PM) [snapback]346151[/snapback]</div>

"OK to use" vs "Fuel efficient use" are different story.
Since you're from UK, please refer to your users manual.
"As your vehicle is designed to have the best fuel economy during normal driving (driving in the combination of gasoline engine and electric motor power), frequent use of the "EV" drive mode may worsen fuel economy."

Ken@Japan

 

OK - I think I've got it .
Whenever I get to a no arrows state I earn 'bonus' miles because there is no direct cost in terms of gas or electricity usage.
Even though no arrows is a very temporary state for me at the moment - over a tankful it would indeed add up and boost my mpg.

As my best ever was at 68.7 mpUKg I'm going to make my next target a 70 mpUKg with the help of no arrows - now that really would be something - - but I may have to wait until summer as Mr Snowflake has appeared.
Cheers

 

<div class='quotetop'>QUOTE(Tideland Prius @ Nov 10 2006, 08:11 PM) [snapback]347101[/snapback]</div>

Yeah - Its not bad for a beginner, but the trade off is all the tailgating, being flashed and abusive hand signals I got going slow in EV mode whenever I could.

I swear people on the same commute go out of their way to avoid being behind me !