I simply bought a 2005 Prius hatchback and have no proviso what the b stand for? It has the typical d, drive, r, reverse and n neutral however what is the b for that’s straight down on the shifter?


“The "B" create something referred to as "engine braking," which mimics the behavior of a timeless transmission: that fakes a downshift to sluggish the Prius if it's descending a hill. Why? To keep the brakes from gift overloaded if you're top top a long, steep grade.” -Google

Here's my attempt at some middle ground in between quick answer and also full classroom lecture. You may currently know some amount of that from driving other cars; I'm not here to assume.

You are watching: What does the b stand for on a prius

A Prius doesn't have actually "gears" in the feeling that other cars carry out as a series of selectable ratios that speed and torque in between engine and wheels. Rather power is routed between engine, wheels, traction battery, and two Motor/Generator units, and the method that strength is directed can produce high-speed/low-torque favor a high gear, high-torque/low-speed favor a low gear, or whatever suggest in between is essential at any kind of given time. Choose a CVT, however without the belt (Toyota calls it an eCVT).

Normally as soon as you're top top a long descent you'd want to downshift so that you don't journey the brakes the whole method down (since the third option is to ride the mountain like a rollercoaster until you shoot off the next of a curve). Talk the brakes renders them hot, which provides them undertake out quicker while also providing much less braking power. Not good.

Downshifting allows a automobile to perform engine braking. It puts the gear ratio at a point where the engine is being thrust by the wheels, developing heat (and noise, however that doesn't have actually much energy value) as a byproduct and adding lots of roll resistance to prevent or at the very least reduce downhill acceleration and take a pack off your brakes.

But Prii don't have actually gears. As soon as you transition to B in a Prius the sets the larger, slower, stronger Motor/Generator 2 to operation as a generator, convert wheel torque right into electricity. If your traction battery isn't full then some of that power have the right to be directed there, however the motor/generators can handle an ext power 보다 the battery fill can. Think of filling a barrel through a relatively small feet in the top from a larger pipe pouring out water; girlfriend can capture some the the water, but due to the fact that only so lot water can gain in the feet at a time the rest has to go what else.

In B that in other places is MG1, which takes that continuing to be power and also spins the engine v it. Now you've converted motion into electricity, then power into heat, helping keep your rate down. The engine will spin even before your battery is full, since the battery can only capture so much of the power at a time (at least without obtaining super hot and killing that lifespan). If you slow-moving down too lot you can lightly push the accelerator and it will mitigate the braking effect before putting any kind of power right into acceleration. If you have to slow down much more use the brake pedal and also it will engage the mechanically brakes.

See more: Or, What Percent Of 120 Is 30 Is What Percent Of 120? = 25 30 Is What Percent Of 120

Save this for long descents, choose coming under from a mountain. Throughout normal use, like coming up to a protect against light or coming under an off-ramp, it's better to simply leave that in drive and give you yourself as much of a long, gentle braking street as you deserve to safely achieve. This provides you more time to capture power back into the battery v regenerative braking and minimizes brake wear.