Cruise Control for Long Road Trip

Which Garmin is that? I need to look at getting a new one. I got mine over six years ago. I liked the features of my Dad's newer one with the pictures of the exit signs in advance, not sure if his has the elevation feature but I would love to have that option. Wow, that is quite a commute you have. Mine is 60 miles round-trip and I thought that was long.

 

Hello all,

First I will admit I am a Prius newbie (less than 2 weeks but over 2000 miles already) but I do have a suggestion about using the CC in hills. I have noticed that my 2010 Prius has about 2 MPH under and overshoot when driving on the highway in hilly terrain. For example, when descending a hill the CC may be holding a steady 62 MPH but at the bottom of the hill and at the beginning of climbing a hill the speed will quickly drop from 62 MPH to 60 MPH. However, as the car is climbing the CC may increase the speed to 63 MPH. This typically will cause the system to go into the PWR range to achieve this 3 MPH increase.
There is a trick I have learned from other vehicles and works well for the Prius too.
At the bottom of the downward decent tap the CC up twice to increase the set speed by 2 MPH so that the CC will maintain the same speed that occurred on the decent. This avoids the loss of speed (momentum) and wakes up the ICE in preparation for the climb. Then as the car is climbing the hill and the HSI is indicating that it is approaching going from ECO (ICE) range to PWR range tap the CC speed down 1 MPH. If the HSI approaches the PWR range again tap the speed down again. If after the second tap the CC still pushes for the PWR range, you might as well let it do it because even if you cancelled the CC and did it yourself you would likely loose 5 to 10 MPH of momentum and still need the PWR range to make the hill.

The other thing I have noticed is good fuel helps the CC stay out of the PWR range on hills. I am luck enough to be able to purchase straight gasoline without ethanol in my area which I have be doing. However I thought I would save a few cent on gas and purchased gas which was E10. This caused CC to push into PWR range on almost every hill and my mileage to drop from typical 53 MPG to 48 MPG. I went back to the station that I get straight gas. On my recent commute to work, which is mixed highway and city driving of 31 miles, I got 58.3 MPG. The weather was similar and my driving pattern wasn't that much different, but after suffering the drop in mileage I did use the tap up and down method more even after getting "good gas".

Lastly, I am still trying to determine if the ECO MODE button help MPG on flat long stretches or not. I think it might. However I have found having ECO MODE enabled in hills is a bad idea. It creates even more lag when transitioning from downhill to uphill and results in more time spent in the PWR range of the HSI to recover.

 

I have the Garmin 2595 LMT, which I bought from Costco. It was on sale last month so I don't know which one they'll be offering this month. It has all the features that my old 660 had, plus free traffic, lifetime maps, and the split screen display of the exit signs, for probably half the price that I paid for the 660. I wasn't sure that it would have elevation display and the various voices, which are the features I loved in my old 660, but it does. And it's better because you can choose to display the elevation on the map screen (in the old one, it was on the separate "where am I" screen. At first, you don't get all the voices, but you can get them by downloading them from the Garmin website.

 

Thanks for the suggestions, Bob G.

 

That one sounds great. Definitely has the features that I am interested in. Something to put on my birthday wish list.

Welcome, Bob G. Wow, that is a lot of miles for 2 weeks! I did notice the discrepancy with the cruise control and thought that I must have just done something wrong when I did try it. I guess I don't have much of a problem with not using cruise control simply because I read the road the same way that I do when I am running one of my races. You anticipate what is ahead of you and react accordingly. I thought it would be tough to do, but it hasn't been. If I drive to Missouri or another flat state, I will definitely try the cruise control again, but when you start getting competitive with gas mileage and goals, it is so hard to risk sacrificing it by trying the cruise control again. It is a nice observation though and I will keep it in mind once I am brave enough to try it again.

 

Thanks Rupert. Yep, I do tend to drive a lot of miles. I finally retired (traded in) my second 1993 Ford Escort Wagon. I drove both '93 Escort Wagons that I owned to over 250,000 miles. The first one I had ordered from the factory in 1992. I drove several other cars in between the two Escorts. They were both still running, but the body was rusting away. They both got 30+ MPG but I realized that the Prius almost pays for itself even when compared to cars that gets 30+ MPG. I refused to buy anything that gets less than 30+ MPG. If I want to burn gas I will put the camper behind my 1996 Suburban....
I was think about what you said about, "anticipate what is ahead of you and react accordingly." I will have to admit the Prius does seem to "roll" up hills and be able to maintain its momentum better than I was expecting. I do also really enjoy rolling into a town holding the "throttle" such that the HSI is right between REG Braking and ECO EV range. Neither am I using braking or consuming battery power, the car is truly coasting. Its cool how well the Prius just coasts along. It makes me think about the government putting limitations on sale of incandescent light bulbs. When are they going to ban Torque Converters and ICE engine braking? More energy is thrown away every day with engines being forced to still consume fuel as the engine is being used as a brake or while sitting in traffic applying non-value added load to the engine.

GM came up with the Dynaflow transmission in late 1947. Now that I have a hybrid vehicle I am I can't believe that it took 50 years for car manufactures to start to move away from the inefficiencies associated with torque converters and typical automatic transmissions.

What's even more sad is the concept of a hybrid vehicle is almost as old as the car itself.

 

My recollection of the conversations was more along the lines of a two lane undivided hwy.

This was about 14 years ago when I was doing CHP ride-alongs when I was interested in becoming a CHP officer.

 

Thank you for clarifying.


There are other laws governing this situation (assuming cars cannot pass due to a non striped line), such as if you have 4 (or 5) cars behind you, you are supposed to pull over and let them pass.

 

I disagree. It does not turn the gas engine on all the time, as far as I can tell. I use it all the time, because it works well. I'm sure you can get better mileage without it by slowing down up hills, and allowing speed to increase down hills (cruise will use regenerative breaking downhill to keep your speed constant). CC is very well designed, I find. It helps me not creep up in speed, and I can enjoy the ride more.

 

We established later in the thread that this was probably due to the elevation of the trip. When I happen to be in a flat area, I will try it again, and hopefully the results will be different.

 

I actually find that I do much better when I use CC for my long hilly commutes. I'm not very good at DWL unless it's a long downhill followed by a short uphill. I find myself having to hit the gas just to maintain a reasonable speed. Today, for example, I started off without CC, and I'd get up to around 55 only to go down into the 40s on the long inclines. After about 10 miles I switched to CC for most of the rest of the way, and managed to reach home at 60.6 mpg - my best reading yet.