Use of B mode in hybrid Camry? - GreenHybrid

barrymckee · #1 (**permalink**) 12-09-2007, 04:18 PM

I have a new hybrid Camry which I am very pleased with after one week. I am asking this forum for advice on using the B transmission mode - the owners manual is not very informative on this. Is is worth shifting into B on most downgrades? Any suggestions appreciated from more experienced drivers.

David Price · #2 (**permalink**) 12-09-2007, 08:32 PM

I find that it depends on the slope. Sometimes it slows the car down to much for me.

haroldo · #3 (**permalink**) 12-10-2007, 01:46 AM

It's like downshifting a manual transmission car. It will save wear and tear on your brakes, but it does not regenerate power to the battery. Use it if you are going down a long hill and don't want to 'ride the brakes'.
As a relatively new owner, I've used it once or twice.
Try it and see if you like it.

rburt07 · #4 (**permalink**) 12-10-2007, 02:28 AM

I think of the Brake position similar to the old Low gear. I was told it uses the generator at a geared up rate to slow the car down. If your on a rather steep grade or pick up enough speed then it switches to the engine (ice) to slow you down. Don't expect to go downhill over 30 to 35 miles per hour using the B position. You can also accelerate just like a regular car in Low gear.

There are two rather steep stretches in the nearby mountain highway where I use the Brake position. Each are less than a eighth mile long with a 30 miles per hour curve at the bottom. Other than that the brake peddle works fine. The brake peddle also uses the generator but at a varying rate while also charging the traction batteries to slow the car.

rmorrow · #5 (**permalink**) 12-10-2007, 05:24 AM

It is meant to be used primarly when a downgrade is steep enough and long enough that the battery will acquire a high SOC, rendering regenerative braking ineffective. Without the regenerative braking, your brake pads will quickly heat up. The B mode helps to circumvent this by slowing the car further with the engine.

skywagon · #6 (**permalink**) 12-10-2007, 06:58 AM

I find the B very usefull on ice and snow compacted streets, slows down without even touching brakes.

hycambrid · #7 (**permalink**) 12-10-2007, 08:55 AM

Quote:

Originally Posted by haroldo

It's like downshifting a manual transmission car. It will save wear and tear on your brakes, but it does not regenerate power to the battery. Use it if you are going down a long hill and don't want to 'ride the brakes'.
As a relatively new owner, I've used it once or twice.
Try it and see if you like it.

The dealer told me that B mode does regenerate power to the battery, and can recharge it in a stretch of a mile or two. Does any documentation say otherwise?

haroldo · #8 (**permalink**) 12-10-2007, 09:07 AM

I believe it does not regenerate while coasting, but it does if you press the brake pedal to assist engine braking.

Quote:

REGENERATIVE BRAKE
When the brake is applied, the motor generator converts kinetic energy into electric energy. When applying brakes, you may hear a sound coming from the motor generator.
However, this does not indicate any trouble.
The regenerative brake works in the following operations.
1. When the accelerator pedal is released, the reduced speed equal to engine braking in a gasoline−fueled vehicle is obtained in accordance with the running mode position of the selector lever.
2. When the brake pedal is depressed with the selector lever in “D” or “B”, the regenerative brake works.

Squint · #9 (**permalink**) 12-10-2007, 10:10 AM

Quote:

Originally Posted by skywagon

I find the B very usefull on ice and snow compacted streets, slows down without even touching brakes.

I don't think it's any different from braking since the point of friction is still the tires.

SPL · #10 (**permalink**) 12-10-2007, 02:24 PM

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