AndyL

To the new owners of CT200h,

I wonder when the car is going from the top of the hill where for normal cars, a 1st gear is required to reduce brake wear, how effective is the "B" mode?

flipside909

B mode is very effective as it uses engine braking to help slow down the car. I use it frequently in all the hybrids I drive, Prius, HS and CT of course. Also because of increased pedal sensitivity, throttle response is a little more lively.

mm767cap

Glad you brought this up, because I hadn't used it before reading this. Prompted me to try it today, and also do some research on how it operates.

The gist, for those who were as lost as I was: B mode does operate as more aggressive engine braking. It's rather dramatic.... enough actually, that you need to pay attention to cars behind you, because you will be slowing more rapidly than they expect with no brake lights indicating.

Apparently it does nothing for fuel economy under most conditions, and actually wastes some gas at times with energy being scrubbed. It's primary use would be for situations like you describe, long hills to keep the brakes from heating up/wearing excessively. Cool stuff.

DelSter196

i live on top of a hill and its a nifty little thing

jimmyc13

Doesn't it charge the batteries during this process though?

mm767cap

It does, but apparently no more effectively than just coasting and letting wheel spin do the recharging. The extra engine braking saves brakes, but apparently exhausts most of the kinetic energy overboard. The brakes themselves do a much better job of recovering battery power.

Now I'm about as far from being am expert on this topic as you can possibly be... I'm just going on what I learned online from doing a search. The consensus of what I read was that it is wasted energy in most cases, and actually hurts your MPG. It DOES save brake wear, but on this car I don't think that will be too much of an issue.

dgstan

The only application for the "B" mode is when you're going down long hills where the battery gets fully charged. The Hybrid Synergy Drive really hates to have it's battery topped off. In fact, in some cases, the electric motor will spin the engine just to burn off an overcharge. When the battery is fully charged, the regen braking is reduced and you have to rely solely on the real brakes. In this case, "B" mode will save your brakes.

tezzmezz

Great post! I was really wondering what the B mode was all about.
This makes a lot of sense too, since the is no option in the car to shift (& lock) the gear into 1st or 2nd, which is handy when going downhill.

rvpps2roks

one thing i noticed is that if you change to "B" mode and come to a stop the engine will remain on and idle and as soon as you shift back to "D" the engine will shut down as it normally does at stop lights or when it "idles"