I read about the "B" position in my manual, but I am wondering what it's purpose is, and if there is anyone who actually uses it, and what they use it for. Any more information on this topic would be greatly appreciated as the manual is kind of vague.

 

I use it going down steep hills, works great as an electric brake...Also when going to fast and I see a CHP, it slip it in, That way the brake lights dont show....heh heh....

 

Haha! Good to know...

 

Good idea thomas1, thanks.

 

I thought B is just for Breaking in the transmission... although I did used it a couple of times going downhill to slow down my RX

 

Do you know if B locks the linkage between engine and wheels (like a manual transmission)? Just wondering if B would result in better throttle response.

 

Based on my experience, I don't think it locks the linkage between the engine and wheels. When I use it going down big hills, it just seems to kick up the regeneration a notch.

Unfortunately for me, the braking effect is not enough so I have to use the brakes anyway. So I pretty much gave up on the B setting.

Jeff
08 RX400h

 

Thanks, Jeff.

 

the B position can be used for big takeoff acceleration also. even more so if used when the battery is full/green. put into B, stand on the gas and hold it down and it'll drain the battery extremely fast as you fly.

 

Curious, Is there Lexus literature to support this claim?

 

It was a joke.

 

On which basis are you saying that? In my experience, if anything, the opposite is true.
In fact, the fact that B position is called "Engine Braking" says it all, really: the engine stays on while coasting, and contributes to the deceleration.
This means that the regenerative braking still works, but the energy required to stop the vehicle (which is normally wasted completely in non-hybrid vehicles, transforming it into heat generated by the brakes) is lower, thanks to the engine contribution.
Otoh, sometimes - particularly on long downhill roads - the regenerative braking goes off automatically, due to the fact that there's a limit to the energy that the traction batteries can receive. You can see that on the power meter: while braking, it normally goes down in the blue area. But when the traction batteries are already full (or almost), sometimes while still braking it jumps up a bit, staying at the zero position. If you have a sensible feet, you can also feel a slight difference in braking, because when the regenerative braking goes off you must push the pedal a tad more in order to keep the same level of deceleration.
Bottom line, also when going downhill, I normally leave the shift in D for as long as the regenerative braking is working. But as I said, in long downhill roads, after a while the regenerative braking goes off automatically, and when that happens, it's the only occasion in which IMHO makes sense to use the B position - more for avoiding to stress the brakes too much than anything else.

 

I shift it into B during inclement weather (i.e. snow storms). Here in Northern New Jersey I recently made a short trip through a couple of towns on side roads. We had about 4 inch's on the ground. Felt more secure and response to me in the snow overall. I highly recommend you try it next time your out and about in the white stuff.

 

I agree with Lexus Ladi...i used it a lot last winter when Portland got quite a bit of snow. Helped me brake with less sliding from the tires.

 

According to Car and Driver, the "B" selection on the Honda Accord PHEV stands for "Battery" and more aggressively regenerates the traction battery when you lift off the accelerator, similar to engine braking in a lower gear like 1st or 2nd gear in a manny tranny. I'll have to try this out the next time I'm driving my wife's Rx. If the ICE can stay off with the throttle off, I think this might work well in slow and go/stop in go traffic where the traction battery drains after 1 mile and doesn't get a good opportunity to recharge.