Braking question

You're on the right track but it's not as simple as a 35 mph cut off, more a gradual shift but also working in tandem.

I'm sure one of the technically savvy members will give you a full description on the exact workings of the brakes.

 

Let me count 5 ways to slow down in a Prius.

1 Parking brake is mechanical cable to rear brakes.

2 Coasting actually does some regenerative braking in the front wheels using the MG1 motor, so it mimics most cars, when you let off the gas it 'feels' like engine braking.

3 If you use B mode on the shifter, you add real engine braking on the front wheels, it wastes energy by using the engine as an air pump, like a Jake Brake. B mode is useed for long descents, over 600 foot elevation change.

4 If you press moderately on the pedal, the Prius uses the MG2 motor to regenerate electricity using the front wheels down to about 7 MPH then uses the friction brakes you would have on a normal car.

5. If you panic stop, you will use your friction brakes on all 4 wheels from any speed.

 

Using B mode will still regenerate, but it will also discard energy by using the engine as a big air pump. It does both if it can.

Tom

 

B or engine Braking mode, only useful if you have a large descent, does engine braking as well as regenerative braking. Once you fill up the HV battery, you will have no more regenerative braking.

B mode has a counter-intuitive sound, backing off the throttle can make the engine run faster, pushing on the throttle can make it brake less, so it slows down. Not what you expect from the 'go pedal'.

I am not overly familiar with Chicago, but I would be surprised if you ever wanted to use B. I have never needed it in Mississippi.
[ame="http://en.wikipedia.org/wiki/Woodall_Mountain"]Woodall Mountain - Wikipedia, the free encyclopedia[/ame]

 

There is no place in Chicago where you need B mode.

Tom

 

If you plan to get to Florida via the Great Smokey Mountains, (fantastic idea, by the way) you may very well want B mode. you may exceed 5000 feet.

Chicago, IL to Orlando, FL - Google Maps

 

There is no place in Florida that you will need B mode. :madgrin:

 

How about Duval Street in Key West? I suppose you could just let the staggering drunks slow you down.

Tom

 

Key West looks like the rest of Florida to me. If you looked at a USGS topo map with 50 ft contours, I doubt that there would be more than 3 contour lines in the whole state.

 

6 actually, almost 7

[ame="http://en.wikipedia.org/wiki/Britton_Hill"]Britton Hill - Wikipedia, the free encyclopedia[/ame]


Technically the Four Seasons Hotel in Miami is taller, but you can't drive a Prius down a skyscraper.

 

Two of the contour lines could cover the majority of the state, and the other four would be on Britton Hill.

 

Yes, I understand, but that would have ruined the joke. :madgrin:

 

My brother, who lives in Ft Walton Beach, claims it is not really Florida, it is just 'occupied Alabama'. They don't seem 'over' the Civil War yet.

 

Britton Hill isn't the same since global warming melted the glacier.

 

We wouldn't call a 350 ft hill with snow on it a glacier. We would call it the bunny slope. :madgrin:

 

Before the continental ice sheets melted, Britton Hill should have been 700 to 900 feet above sea level, even without its own glacier.