Cruise Control VS. My Size Thirteen

Well, in my 2G the only problem with cruise control is hills. It tries like mad to maintain exactly my set speed so the engine revs up and out of its most efficient band. (Traffic permitting I prefer to bleed off a small amount of speed on the way up, occasionally accelerating just a bit before I get there to compensate.)

If anything I think that the 3G should have less of a problem in this regard. You have the bigger engine so it will not have to work quite so hard to maintain speed. And even if it does you can always step it down a mph or two with the cruise. I notice your location says 'midwest' which might disqualify you from this problem as well. There is no reason not to use cruise control for FE reasons when it's dead flat.

 

I have read some threads here that talk about the cruise control being super dumb compared to a human driver.

I may be dumber than avg in that case, because on a few longish trips I tried the cruise control on my Gen III and was very impressed with it over the long haul -- yes, it tries to maintain speed up hill, but it never seemed to give the engine more than needed to do so. And on flats, it seems much better at holding the lowest possible acceleration, consistently without fluctuation.

I am sure the seasoned hypermilers here find it to be super useless -- but on the way back from the coast, I used it 80% of an 80 mile drive, including up over the coastal range (Oregon), and ended up with 55.6mpg. Seems pretty good.

 

Don't try to force the engine off. It won't help your mileage. If you haven't done so, you might want to read the sticky about improving mileage.

Tom

 

If you use cruise on the highway then try one little trick to improve mileage.

Accelerate manually before you hit a hill. Bring your speed up maybe 5mph over cruise speed starting 100 metres before the start of a rise and hold your foot steady. Aim to just get down to cruise speed as you hit the crest of the hill and then let cruise control take over again. There is no need to disengage cruise, just help it along as it can't see hills.

Makes a difference but you can still relax.

 

Man, I hear you! I am in the same boat and I just can't keep from doing it. I really hate how the other drivers mess up my rhythm too. I was hoping that under the cold weather I would just let the mpg go and not worried about it but now I am really trying to keep things above 50 mpg! (more stressfull). One thing I did that helped a bit was block the lower grill. I saw at least a .5 mpg possibly a full 1 mpg. I was hoping someone else could confirm this.

Well try to relax dude and enjoy the car.

 

Okay, here is the link:

http://priuschat.com/forums/gen-ii-prius-fuel-economy/14701-new-owner-want-mpg-help-read-first.html

All of the energy in a Prius comes from burning gasoline. When you drive a Prius in electric vehicle mode (EV mode) the energy comes from the battery. This means the energy started out as gasoline, was burned in the engine to make mechanical energy which spins a generator to make electrical energy. The electrical energy is stored in the battery by converting it into chemical energy. To use this stored energy, the chemical energy is converted back into electrical energy. The electrical energy is converted back to mechanical energy in by the motor. That's a lot of conversions, and each one wastes energy.

When you get that great 100 mpg in EV mode it's like getting a cash advance from your credit card. You have free money for a month, but then you have to pay it back, plus 21% interest. When you borrow energy from the battery you have to pay it back with interest.

For good mileage, EV mode should only be used in a few special situations. The most common are creeping in stop and go traffic, and moving short distances where it doesn't make sense to warm up the engine. Otherwise you want to avoid EV mode.

Pulse and glide is another special case, where you accelerate hard with the ICE, and then coast, and repeat. In this case, obviously, you want to glide, not use battery power.

Tom

 

I just want to bring up to your attention (if you do not realize this already, or to remind others) that you have the 17" wheels.

I had a 2005 Prius and now 2 2010's, one is a IV and the other a V.
The IV gets around 55 m.p.g. easily, but the V gets about ~51-52 m.p.g. like you do and it is very hard to keep 52 with the 17" tires (especially driving highway)!

Tuesday night I drove to my dealers new Toyota dealer invitation meeting and achieved 55 m.p.g. to the dealer, but that was killed on the way home (just way too hard to keep that 55 m.p.g. with the 17" tires, and we wanted to get home) and all I achieved was my 52 m.p.g. when I arrived back home.

I spoke with my friend that has a jetta TDI and he only gets ~38 m.p.g. now (he has the 17" tires and keeps them at 50 psi) so I am happy with what I get but wish the 17" tires would roll better, I am going to try 50 psi today in them and see if any difference.

Best of luck
Don

 

With that many miles per year, you are in an excellent position to make your own "MPH vs MPG" chart. Just keep a handy pad of paper and start recording segments:

• miles
• MPG (indicated)
• average speed
• temperature
• start-stop locations (optional)

Load the data into a spreadsheet and then you can understand where this data comes from:


Within a week, you'll have enough information to see the patterns. Then adjust and see what happens.

Bob Wilson