Toyota Prius owners, I need help?!?
(2011-06-17 14:15:16) 1. Says: I bought a '05 Prius and it didn't come with a manual. I do have a carfax though, great car! Love it. But my question is what does the B on the gear stick mean and what can you do with it and so on, thanks in advance2. Says: Unfortunately, Eric is only partially correct. B mode is engine braking. When going down a long steep hill, if you use the brakes the battery may fill up before you reach the bottom. this means that you are now relying only on the friction brakes. Using B mode adds engine drag to the picture, which lengthens the time that it takes for the battery to fill up.There is one exception to this. If, and only if, you engage B mode below 20 mph, then the motor/generators will simulate engine braking. However, this is of little practical use because normally you stop quite quickly when you engage B mode below 20 mph.
Note that the Prius does not shift gears, so there is no value to using B mode going up hills.
A few additional points about B mode:
B mode can be shifted into at any time.
If you use B mode all the time mpg will go down because the engine will be running all the time.
For short hills, it's best to use the brakes because B mode causes less regeneration (because some of the kinetic energy has been turned into engine friction).
B mode can be used to smooth out braking on washboard (gravel) surfaces.
You can download the manual from http://techinfo.toyota.com/ There is a $10 fee for a day's unlimited downloading.3. Says: Congrats on the Pri!
The B is a mode that's designed to simulate shifting to a lower gear in a regular car to help hold the speed down on a long descent.
You can shift into and out of it at any speed to help hold you back while going downhill.
There's no reason to use it for normal, level driving--it can reduce fuel economy if used while not descending.
On the Prius, it accomplishes this by engaging one of the motor-generators as drag. This produces more energy than can be stored in the hybrid battery pack so the other motor/generator spins up the gasoline engine as a load to use up this extra energy, even though there's generally no gasoline going to the engine in this state.
The B-mode is helpful because you don't need to use the brake pedal as much. It's nice for long descents on snowy roads as it provides a constant braking force that isn't likely to cause the wheels to lose traction.
Also, if you were to use the brake pedal the whole time, the regenerative braking will fully charge the hybrid battery pack (this doesn't take very long) and then the car will switch braking duties to the wheel brakes, which can overheat and lose function with too much use, just like any car. Tag: Toyota Prius owners, I need help?!?