Use of B mode in hybrid Camry? - Page 3 - GreenHybrid

skywagon · #21 (**permalink**) 12-13-2007, 09:07 PM

Quote:

Originally Posted by rburt07

No I doubt using the Brake mode would hurt anything. I do know if you use it when the engine is off, it will start the engine. I understand that the B mode is like a pre-set brake. If the car goes fast enough the generator then goes to the engine for the braking or gearing down. I would think above 40 or 45 miles per hour.

That may be because the generator/motor is more effective up to 40 miles per hour. Although it can aid the engine though at higher speeds when needed if you have a high enough charge.

I have seen the battery full charged in the Multi Function Display while coming down a mountain. Evidently the engine was used more even around 40 miles per hour due to the battery being fully charged. A Toyota tech had earlier told me that was another reason they like to keep the battery charged at 80%. That leaves extra room for the generator braking. The main reason for the 40% to 80% charge was to extend the life of the nickel-hydride batteries.

This same tech told me there is a early prius around town with 225,000 + miles on it. The batteries have never been touched. That gave me a good feeling. He said the newer models, the batteries are in small groups of plug in packs and are easy to change out if ever needed.

I wish someday that Toyota would make a hybrid where we can run in the EV mode at 50 miles per hour.

Took mine out on a frozen lake today and drove hard in D and hard in B, B has more control on the ice period. if you do not believe just try it. in B mode car was just plain more controlable on glare ice.

jsalva11 · #22 (**permalink**) 12-13-2007, 09:30 PM

Quote:

Originally Posted by SPL

Both 'D' and 'B' modes regenerate energy to the battery, provided the battery isn't "full." It's just that 'B' mode does more of it — it gives more braking effect, some of which is regenerative, and some of which is true "engine braking." Also, once the battery is "full," neither mode will regenerate at all. In 'D' mode, all braking will be by the (lossy) friction brakes; whereas in 'B' mode, the ICE will be spun by the wheels (via the two motor-generators) to give (lossy) engine braking. So, with the battery "full," all braking is lossy.

Stan

I have a FEH and as far as I know, the technology does not work too different from the one on the Toyotas. On the FEH, when using the "L" mode (like the B on the Toyotas) any time you release the gas the regen will kick-in. I use it all the time to slow down and force-charge the battery. No difference with "D" on acceleration. Now, on a downhill, if the battery fills up then that overfill power is directed to one of the generators to "SPIN" the ICE. There is never a hard connection between the ICE and the wheels. If you drop the gear on "B" whith the ICE on the ice wont revv up like on a normal car. Once the battery is full, the extra energy is used to have one of the motors turn the gas engine, burning that extra power that has no where to go.

My 2006 Honda Civic has a more "traditional" transmission and using the S mode actually does reduce the gearing, spinning the engine faster like on a normal transmission. Not on the FEH. On the Honda, once the battery is full the regen begins to reduce itself until it's gone. Then the car glides down easily almost like in neutral (the Honda closes admission and exaust valves on all cilinders to reduce engine drag when no gas is applied to the engine) You are left only with a weak engine braking and normal brakes.

Juan S. Fernandez
2006 HCH / 2006 FEH 4WD
Los Angeles, CA

rburt07 · #23 (**permalink**) 12-14-2007, 02:41 AM

Quote:

Originally Posted by skywagon

Took mine out on a frozen lake today and drove hard in D and hard in B, B has more control on the ice period. if you do not believe just try it. in B mode car was just plain more controllable on glare ice.

I can understand that. In D the tires would spin faster and in B mode they would turn slower when accelerating.

Your ice driving reminds me of when we lived in Garland, Texas. When it iced over there I would head to the nearest football field parking lot and learn ice driving.

Here in Alamogordo, NM its mostly desert. It did snow here a few times but with very little ice.

CkGoGreen · #24 (**permalink**) 12-31-2007, 04:39 PM

green prius here! 7 months young. i hadn't figured out the B mode; just thought it was a 'low gear' until a friend said it regened on a downhill and you don't have to worry about the speed. that freaked me out - until i could get on this sight and read for myself.

so i don't have to worry about going over 40 like with a conventional car huh? like that! i have always used low gears for hills and 'not touching brakes' etc so this gives me a whole new outlook on the car.

i'm still such a newbie...what's ICE and SOH?? thanks for all the good info.

Ck

dledeaux · #25 (**permalink**) 12-31-2007, 05:32 PM

Quote:

Originally Posted by CkGoGreen

green prius here! 7 months young. i hadn't figured out the B mode; just thought it was a 'low gear' until a friend said it regened on a downhill and you don't have to worry about the speed. that freaked me out - until i could get on this sight and read for myself.

so i don't have to worry about going over 40 like with a conventional car huh? like that! i have always used low gears for hills and 'not touching brakes' etc so this gives me a whole new outlook on the car.

i'm still such a newbie...what's ICE and SOH?? thanks for all the good info.

Ck

Yeah the CVT really changes the old rules. Its nice.

ICE = Internal Combustion Engine
Don't know what SOH is.

We should come up with a translation guide

David Price · #26 (**permalink**) 12-31-2007, 07:41 PM

I think you mean SOC, which is "State Of Charge" of the main battery.

schmidtj · #27 (**permalink**) 01-01-2008, 04:11 AM

Quote:

Originally Posted by David Price

I think you mean SOC, which is "State Of Charge" of the main battery.

Or maybe SOL ?

rburt07 · #28 (**permalink**) 01-01-2008, 11:29 AM

I have had better luck in the mountains by slightly using the brake peddle to slow the car for curves in the road.

The brake mode seems to me it's for really steep grades and is designed more to keep the car about 35 miles per hour or slower on the descent.

I have found when the car is going downhill at about 65 miles per hour the manual brakes don't slow the car as well as at slower speeds. My guess is that they can't use the regeneration as well at the higher speeds. Could be its using the engine and some physical braking to slow the car instead.

SPL · #29 (**permalink**) 01-02-2008, 11:16 AM

See my post #24 in the thread "Regeneration choices."

Stan