Driving in "B"

Read this thread for a good discussion on engine braking. Notice the first reply, posted by Moderator efusco -- particularly this:

I think your salesperson is confused. :blink:

 

Yes, it is most probably your local short trips. Not enough time to cleear the warmup cycle, and start reaping the higher mileage.

 

Short trips will almost always result in a lower MPG. The engine needs to warm up before it gets really good gas milage. This is true for all cars, but is more obvious in the Prius because you have instant feedback. Additionally, the engine intentionally runs rich during the first couple of minutes of driving to warm up the engine and the emissions system. If you drive 10+ miles, you will notice on the Consumption screen that the first 5 minute bar is almost always around 35 MPG and the subsequent bars are in the 50 MPG to 70 MPG range. If you never drive more than 5 to 10 minutes at a time, you will always end up with averages in the low 40's.

There are many articles on the board about how to get better gas milage. After reading the articles, you might get the impression that it's a lot of work to get good gas milage, but it really isn't.

Here are a couple of points...

1) There does seem to be a break in period. Most people tend to get significantly better gas milage after 5,000 to 10,000 miles. It may be an engine break in period, or a driver break in period, or a combination of both.

2) Avoid jackrabbit starts. You can still accelerate at a reasonable rate, just don't floor it at traffic lights. Going 0 to 40 in 5 seconds won't get you where you're going any faster than going 0 to 40 in 10 seconds, and overly fast accelerations really burn up gas.

3) Constant speed is your friend. Keep at least 3 car lengths between you and the car in front when you are at cruising speed. This allows you to make subtle speed adjustments when the trafic speed varies without constantly accelerating and decelerating.

4) Once you've accelerated up to your cruising speed, lift your foot of the pedal and then gently press it again until it reaches the point where you can maintain your speed. This seems to indicate to the car that you finished your acceleration and it changes the power characteristics of the drive train. For instance, you will notice that if you accelerate to 30 and leave your foot on the gas, the engine will keep running. However, if you lift your foot and then gently reapply it, the car will usually turn off the engine and switch to using the battery to maintain speed.

5) Don't expect the car to run off the battery all the time and don't try to force it to. The battery isn't very big and the Prius can't go far on the battery alone. However, it is sufficient for maintaining speed in the 30 - 40 mph range for long stretches on level ground. Let the engine come on during accelerations and just accelerate normally.

6) Anticipate stops and coast towards them. Use slight pressure on the gas pedal to extend your coasting as you approach stops and lights. If you take your foot off of the gas pedal, then the car attempts to recharge and this slows down the car. A light touch of the gas pedal will put it into a mode where you have no moving arrows on the Energy screen and it will coast a long distance. This is hard to accomplish, particularly at first, but even if you over-press the pedal a little bit and are using a little energy from the battery, you're OK. Basically, the trick is to stop accelerating when you see the red light or stop sign and coast the rest of the way. If you use the technique described, you will be able to coast all the way to the light without losing much speed.

7) The cruise control is overly agressive, particularly on hills. The cruise control will floor it going up hills to maintain the programed speed, even in situations where you would have tolerated a 2-3 mph drop in speed. It's the difference between 8 mpg going up the hill and 35 mpg.

You don't have to be staring at the Energy screen all the time. Just do what I described above, and after a couple of thousand miles, you should be getting much better gas milage.

To recap...
Accelerate moderately. Maintain constant speeds. Lift your foot from the gas pedal and gently reapply once you get to cruising speed. And use gental pressure on the gas pedal to extend your coasting as you approach stops.

 

Drugs are a big problem in the US! :huh:

B is for braking and you can achieve the same thing by using the brake pedal.

 

My dealer referred to "B" as the "bullsh__" gear. LOL.

I've tried it down the steep hill on my way to work to see if I notice a significant charge build up and it does not hold a candle to what I've observed w/ a gradual off-ramp experience getting of I-495 w/ minor/moderate breaking.

Worth checking out the "other" current (and heated) thread on this topic... http://priuschat.com/Rookie-QuestionB-Drive-t11737.html

 

When I got my Prius, the salesperson told that 'B' stood for 'battery' as in the car would only use the electric motor in this mode. He didn't realize he was wrong because the things fly off the lot so quickly, he had never driven one.

I am guessing this is what your salesperson was thinking. In my experience, the salespeople are horribly misinformed when it comes to the Prius. However, I can hardly blame them...it is a radically new technology.

 

uhhh... hasn't the Prius been out a few yers now (sarcasm intended). If they are misnformed about the car they are either selling, or attempting to sell, they should say I do not know but I know someone who does, or I can point ou to a website that can answer your question.

This is NOT new technology. It's been around as long as the ipod (or longer honestly) and every 7 year old know about a ipod.... how many know about the HSD??

 

I can and do blame them. They at least have an obligation to keep their mouth shut if they don't know the answers, or they could try "I don't know but I'll try to find out for you". There is no reason a salesperson couldn't take the owners manual home and read it, except it might make them miss Desperate Housewives. The truth is they have no real interest in helping their customers, once they get your money that's all they care about.

 

Well - I can't say I don't agree with you all - I was just trying to be nice

 

Let's say we agree that it's relatively new technology. It's a saleperson's job to know what they are selling. If they just spent 1 day doing a little research, they'd know enough to sell them.

 

I used to use the "two second rule" to avoid tailgating and a possible rear-ender. Now, I make it about four seconds to have that extra gliding room. (Two second rule: The rear bumper of the car ahead passes a sign, pole, line, etc. Count "one thousand one one thousand two." If your front bumber passes that object before you finish counting, you will likely hit that car if they slam on their brakes.) At higher speeds, three car lengths just isn't enough to avoid a collision during sudden stops.

Lmao!!

Yeah, these salespersons should understand the cars they are selling. My sales guy knew the car's main functions and design (even knew what "B" is for), and for more technical questions, he referred me to the dealer's "Prius Guru" (his words). Overall, I'd have to give the guy an A for knowing the car.

Genalex, if you get one of those purchase/lease surveys from Toyota, be honest about her knowledge of the car, which sounds like "poor" to me! This will cost her some of that commission, and it may make her do some basic research for her next customer.

 

You know an easier way to do this one is to just put the car in neutral when you want to coast to a stop, and then put it in drive when you get closer so when you brake it uses regen braking instead of friction braking. I think when you're in neutral it uses only friction braking.

 

Yeah, no regen when in neutral.

 

I admit I have't read all the responses. So, forgive me if I plow the same ground. The 'B' setting is very effective on long, steep grades...so much so that sometimes I have to press on the gas to maintain 70 mph. The hybrid system gets a little schizophrenic when I do that, alternately engaging and disengaging the big motor from its task of slowing the car. On occasion, I've neglected to switch back to 'D' at the bottom of the hill, and the car seems to behave normally as long as I don't take my foot off the gas (throttle input overrides engine braking).

I haven't intentionally driven in town in 'B', but I'd think the severe engine braking would be very annoying and hard to modulate.

 

I just take the attitide that salesman's knowledge will be limited at best... and often times just plain wrong. I consider it my responsibility to understand what i am buying... and part of getting good information is knowing that a salesman's knowledge is usually poor.

/Jim