Cruise Control on Highway for best MPG

CC wouldn't affect the pedal input, since it's an electronic pedal.

 

That's interesting that it didn't have CC in a higher priced car. Maybe it was a Japanese thing.

 

Roger,

When I was referring to "normal" mode, I was implying to use it when you are puttering around town in normal traffic. As I stated in details further down the post IIRC, I use ECO when I am on the highway ONCE the cruise control is engages. The only reason I use the ECO is that is has been said that the A/C works more efficiently in ECO mode on the highway...

Hope this clears up any misconception based on the information I posted.

Ron

 

Ok, I thought maybe you didn't catch my drift. Sorry about that Roger...

I am not perfect, the good Lord is still working on me

Best of luck to you. Let me know how you like "Regular Mode". I am a CC guy on the highway unless I am climbing some steep hills. Then I kick out the cruise and work the foot pedal letting the speed drop gradually. Burns a lot less fuel that way and less wear and tear on the ICE.

I have a feeling if you will try "Regular" mode around town on local roads, after a while you will begin to appreciate it more than the ECO. You get the same control, just don't have to push the pedal as far. I utilize the HSI indicator a lot. That tool really helped me master the Gen III quickly and determine which modes worked best for me. Coming from a Gen II helped me also.

Later,
Ron

 

I have a daily commute of over 100 miles, up and down hills/mountains. I use cruise control almost all the time except when in stop and go traffic near my house. I find I get much better mileage by letting it control the throttle, rather than me.
I get between 51 and 58 mpg in the summer, on my Michelin Energy Savers. But mileage drops to 45-49 in the winter. I drive about 10 miles of my 50-mile one-way commute at 25-55 mph, about 20 at 60-65, and the remaining 20 at 68-74.
I don't like the ECO setting and I don't feel it improves gas mileage.

 

Using ECO mode and CC on the highway works great for me. I tried manual on the way to a customer I service that is about 5 hours away and CC on the way home to compare the difference. I filled up and check the actual miles before each leg of the trip and about a mile from the house and it was less than .5 mpg and I was doing the best I could to glide down long hilly highway stretches. This was driving from Atlanta to about 75 miles above Birmingham AL which has as many hills as the edge of the Smokeys has to offer. I did the same when I visited my father about 6 hours away in Mobile AL. which is a much flatter terraine drive with similar results. I say set it and forget it. The computer does a very good job of maximizing things. I was amazed, watching the line on the display, at how the car always looked for that sweet spot.

 

How do you get your model to stay in EV mode at such high speeds ? I'm a new driver of a 2011 Prius Three and it seems to not want to stay in EV mode the moment you accelerate above parking lot speed.

 

He has the Plug-in Prius, which has a higher EV threshold than your regular version.

 

Correct. Sixty two mph max while in EV mode.

 

Cruise control makes it a lot easier to go a long ways, but you cannot maximize mileage by using it. The car cannot respond to road conditions except to speed up too quickly or to slow down in places where is may or may not be appropriate. I just finished a 910 mile trip running at the speed limits (65mph and 70mph about half and half). I got 58mpg for the round trip, only using cruise for about 100 miles. All cruise would have been around 5mpg less. There are a lot of times where mileage comes in second to comfort, however.

 

Yes. That second to comfort thing you mentioned is called opportunity cost. Is it really worth it to diddle with pedals for 900 plus miles instead of sitting back and enjoying a little music? After 4 months of stressing over getting (and let's all admit it, bragging about) a few mpg's, the science experiment part of my Prius has changed to being happy with a really economical car. I was given a nice inch so I've chosen not to be greedy and demand a mile of myself.

That being said. I will tweak a guitar amp for weeks searching for the right tubes and NOS components to make that thing sound like Clapton does on "Layla". Will my audience notice? Probably not. I may as well be playing some poser of a solid state modeling amp but, hey. We all have our obsessions.

 

I'm not sure..., I've been sceptical of cruise control usage in the past, it's effect on mpg. But, on reasonably level highway, I've watched the ScanGauge with the cruise off, then on. Cruise keeps the instant mpg low, and steadily so, reacting just enough on slight upgrades. Maybe if you're doing all-out pulse-and-glide you'll do better.

But I can't see cruise control imposing a 10% penalty. For me I think it would be neck-and-neck, at best.

If you've got a regular run, maybe try without one time, with the next.

 

Since the speed limit you say is 75, why then, sir, do you set the cruise at 81 mph? You know that the extra fuel required to go that extra 6 MPH is considerable and certainly the risk of being ticketed is greater and if some thing goes wrong in front of you it will take you longer to stop and to avoid the hazard and when you hit something the damage and the risk of injury will be greater. So what is the "very good" mileage that you get at 81 MPH? Consider the mileage you could get at 60, 65 or 70, traffic permitting, of course?

 

Unlike you and me, some people live in places where 6 mph over carries essentially zero risk of a ticket.

Actually, many people live in such places. And even forget that anything else exists.

 

It's kind of like bolt lengths (I know, bit of a stretch):

Manufacturers are told the bolt length may vary plus/minus 1/4" in typical case, guess which extreme they go to. You can check it out the hardware store: take along a short ruler or tape measure and check a few; they're invariably 1/4" shorter than spec'd.

 

The interstate is posted at 75, traffic flows at around 80mph.

I do not believe that this extra 6 mph is having a considerable effect on my mileage.

There is no 'threat' of being ticketed. None!

"Goes wrong in front of me"? Then I slow down. When anyone is on the side of the road, I generally can see them a mile in advance. Horizon-to-horizon there is rarely more than 4 or 5 vehicles on the interstate. It is never crowded.

 

From testing at Cleanmpg.com, on a Prius hatchback at steady state of speed, they got 57.9 mpg at 60 mph, 52.2 at 65, and 45.5 at 70 mph where they stop testing. I would guess going from 75 to 81 would have a similar impact.

 

I trust you have seen this chart, which suggests otherwise?
Updated MPG vs MPH chart

 

We generally get around 51 less in winter, more in summer.

We drive a bit less in winter as our driving routes are shorter. Crossing rivers in summer requires driving to the nearest bridge to get across, lakes and ponds need to be driven around, etc. In winter, fewer people bother with bridges.