I just got my Prius 2006 in black with Package 6 and i love it, but I've never driven a Prius before. Can anyone tell me the advantages and disadvantages of using Engine Breaking vs Drive? Does EB improve mileage?
Short answer is no. On a long (i.e. big mountain long) the B mode provides engine breaking when the battery can no longer adsorb a charge. It acts like compression brakes (jake brake) or down shifting. It decreases milage except when used appropriately on a long down hill.
"Can anyone tell me the advantages and disadvantages of using Engine Breaking vs Drive? Does EB improve mileage?"
Welcome to the group. Enjoy your new wheels. The driving experience gets better as you grow accustomed to the car.
* If you find yourself decending some exceptionally steep grade (where the friction brakes might over heat), "B" mode can provide some compression braking from the gas engine.You can't hurt anything by trying it out.(Don't forget to shft back to "D".)
Do you ever downshift a conventional transmission (auto or manual) to facilitate braking..? If not.. then you won't use the "B" in the Prius.
** It will NOT improve gas mileage.
I actually found it usefull when going downhill in slippery snow.
I was going down a very slippery steep hill with a banked turn. There was a whole line of cars ahead of me and everyone was creeping down the hill at less than 10 mph because it was so slippery. Because the turn was banked slightly, you had to be very carefull about applying the brakes because too much brake pressure would lock up the brakes and we were going too slow for the ABS to function. And when the brakes locked up, the car would slide towards the shoulder because of the banked road.
So, I just put it into 'B' and it gently kept my speed down pretty well with only an occasional press of the brakes.
I ended up handling the hill fairly well after that. The Jeep Cherokee in front of me pretty much slid down the hill at a 30 degree angle.
Rule of thumb: Unless you have the feeling that you're dangerously riding your brakes - and on the Prius, you REALLY have to ride the brakes even to engage the brake pads! - then B mode is unnecessary.
Living in Colorado, I've used B mode many times in mountain driving: It's very handy when you encounter a four-mile stretch of road with a seven percent grade. (And the battery will charge to 8 bars anyway...) But I've only found one hill in CS that was long enough and steep enough to warrant it. It's not surprising that a flatlander such as Hyperion has never used it.
I live in a somewhat hilly area of SD but I just don't have much need for the B mode. I find it better to utilize that slight downhill increase of speed to make it up or through the next incline.
Secondly don't be surprised if it takes a while to "settle in" many of us are still learning about our vehicles. After gettting 40-41 for my first 5000 I am hitting 43-44 with more consistency as I learn to drive more efficiently. Enjoy Your new Baby!!
So far you know what B mode does and how it does it. However is not about knowing how it works, but knowing what it is designed to do.
Think of B mode as a lower gear in an automatic. It is common in hilly country, or in cities to use a lower gear in an auto for the purposes of avoiding the use of brakes on long downhill and for the purposes of assisting a stop in the city. If a light turns red sooner than I expect, I will use B mode to assist my stop rather than rely on the brakes entirely. It is an excellent stopping assist if you need it and engages quickly, faster than moving an automatic in to 2.
I also use B as a stoping assist. Lower MPG is offset by slightly less wear on the brakes. When the carpool lane comes to a stop it often does so in a hurry, I appreciate the additional stopping power.
The main advantage of using "B" mode as stated already is to assist in slowing down on hills and mountains. I use it every time I go over a hairpin curve mountain gap that descends 1,300' in 3 miles as part of my 3 day a week commute. It certainly helps save the brakes. However, I only use it until the battery is fully charged which can vary from almost to the bottom to just half way down (depending on the weather and road conditions where slower speed makes the battery charge to full quicker). At this point, as the motor begins to rev or spin much higher and louder (to prevent overcharging), I shift back to "D" where, especially under a fully charged state, there is still a moderate engine braking effect at a still noticeable but safe ICE spinning speed.
A disadvantage is lower MPG in regular driving (not downhill), although like jeromep and copek, I have on rare occasions used it for additional stopping power, just like downshifting.
The question of if MPG is lower when using "B" in a descent where the MFD shows a constant 99.9 MPG depends on whether the MFD is completely accurate or that if under "spinning" mode, the ICE is not actually burning fuel. I have not seen a satisfactory answer to this question.