Cruise Control on Highway for best MPG

You can use the AVG gauge on the ScanGauge to track the segment mileage. It becomes clear pretty quickly that cruise lowers mileage. My road trips do not include any flat roads (for any great distance), so it may be that for long, flat stretches cruise might be better.

 

Driving 6 hours to my fathers, fairly flat highway drive, all CC and drafting trucks from a safe distance, I got 54mpg. Driving from Atlanta 5 hours to Decatur. Al, much more hilly, with CC and the occasional draft, I got almost 52mpg. On the way back, using CC but disengaging and going into glide down all hills, I got close to 54mpg. Both trips were at or very near the posted limit of 65mph (near meaning a bit under).

The "proof was in the pooding" for me. The difference being so negligible that the opportunity cost far outweighs any gain in not using CC on a long highway trip.

Plus the hyper focusing made me feel as though my attention was not as much on the environment around me and more like I was playing a video game while driving. Someone needs to do some research on the safety factor. There is no way you can totally be attentive to other vehicles around you when you have your attention on an assortment of gauges. Probably on the same par as texting while driving.

 

So neither trip was done without substantial cruise control. I am not sure where the proof is. Texting while driving is illegal where I live. Keeping track of your speed is pretty much required.

 

Just a couple of thoughts:

• drag forces are a function of speed, not variation in speed
• engine efficiency can become non-linear at higher power settings
  • before cooled Exhaust Gas Recirculation (EGR), the old 1.5L engine had to run a rich fuel mixture to avoid burning out the catalytic converter

I found the cruise control even with a 1.5L engine can achieve excellent results even in hilly terrain by simply changing the speed to keep the engine power out of the 'fuel enrichment' regions. "Patting" the cruise control stalk up increases the speed by 1 mph and down, decreases it. You can stack up to three, 1 mph changes, and keep adjusting as needed. You don't have to touch the accelerator to change the cruise control setting. And on a downgrade, shift into "N" and keep up with the semi-trailer trucks.

In fact using semi-trailer trucks as pacing vehicles is an ideal practice for cross country, NHW11 driving. Semi-trailer truck climbing speed is perfect to keep out of the 'fuel enrichment' regions. On the downgrades, shifting between "N", "D", and "B" keeps up when they are high-balling.

Unlike the accelerator, changing speeds with the cruise control is 'less frantic.' Your passengers will barely notice the exceptionally smooth ride. So less energy is lost in inertial energy changes.

Bob Wilson

 

The first trip was all CC. All but the glide down hills on the second trip was also.

I am actually heading back to Decatur, the 5 hour trip, this morning. I will do all CC one way and no CC the next.

 

If you have a GPS, look at elevation at start and end of trip. I go to my son's house 40 miles away, and get 4 mpg difference (more) coming home mostly due to the 350 ft elevation difference.

 

Just pulled over for coffee. I am driving without CC on the way there because I drive with it last time. I'll compare this leg to the one going up last time with CC.

 

I live in WV, drive 160-220 miles/day for work. I use CC a lot on the highway speeds of 60 and 70. As I drive all day, my knee would be killing me if I didn't have CC. I've been getting 51-52MPG so far this summer. Pretty good considering the hills are very substantial. I get upwards of 70+ MPG going down to the valley and then probably 25-30 coming back.

 

Did my 5 hour trip with CC going and no CC on the drive home. No drafting either way and keeping near the speed limits the entire trip (except for the glide down hills). I got right at 52mpg using CC and 53.2mpg and a stiff leg without CC. I've never hit 55mpg on the highway.

 

This is my mileage after the 900+ mile round trip to the coast. All in Eco, no cruise. No sore leg. It is just a game...

Pat

 

I have finally hit 55mgp on the CONS meter this tank. I rarely drive more than 30 miles on a weekday and my commute to and from work is hilly no matter which route I seem to take. My 7.7 miles to work usually yields, depending on lights and traffic, between 50mpg as high as the low 60's. My commute home, which is at a lower elevation by maybe 200 feet, I consistently yield between 65 and 75 mpg, and have hit 99.9mpg on several occasions but still can't get the CONS number to go over my record of 55mpg.