Best Highway Cruising Speed for MPG's

[C-MaxSea]

Paul, trip was mostly 60-68 mph freeways, description in notes 22 & 24 above, and #s 4 & 6 below. Summer driving. 

 

Note 22 above is the crux - repeatable route to 48MPG highway, any day of the week now - 5 miles to freeway 38-42, then a steady climb to 45-50 gauge (43-48 pump) subject to time of year.

http://fordcmaxhybridforum.com/topic/4207-shout-out-mpgs/?do=findComment&comment=48651

Edited September 6, 2014 by C-MaxSea

[ScubaDadMiami]

Just so it is clear, other than on flats with Eco Cruise, you will actually do better by reading the road conditions and flying manually and without Cruise. The issue will be that you will have to do a lot of work for the extra MPG. That's just too much work for long trips at highway speeds.

[C-MaxSea]

Just so it is clear, other than on flats with Eco Cruise, you will actually do better by reading the road conditions and flying manually and without Cruise. The issue will be that you will have to do a lot of work for the extra MPG. That's just too much work for long trips at highway speeds.

 

Agree, and to be sure clear is clear, SDM, I think you are stating that manual mode (driver control without ECO Cruise) is too much work, therefore stick with ECO Cruise - exactly what I have been saying, and encouraging folks to do, in order to pull themselves up into the 40s, or mid & upper 40s if they want, conditions permitting, by tempering their speed.

 

((( and as you say "flying manually" without ECO Cruise 'would be better';  but I doubt I could 'beat the machine' anyway, even if I tried.  Bottom line, we want nothing to do with the headache of micromanaging the terrain with manual methods (we are way too lazy), other than a cruise control toggle tweak now and then (which may or may not be helping us a bit)))) 

Edited September 6, 2014 by C-MaxSea

[SnowStorm]

C-MaxSea, I agree and could hardly agree more.  For newcomers especially, set EcoCruise at your desired speed and forget it!  (I say "newcomers" because us "old-timers" are set in our ways and won't be convinced by anybody else anyway!)  I repeatedly drive a non-stop 30+ mile stretch at 55 mph - almost level but just enough slope change to go in/out of EV occasionally in Eco-Cruise.  I once tried micromanaging the EV mode (for 30+ miles!) and couldn't tell any difference.  A lot of work for nothing.  (But maybe I need training?)

 

I also don't buy the "sweet-spot" urban legend.  The faster you go (all other conditions the same!), the lower the MPG.  Period.  Of course I haven't heard the definitive definition of "sweet-spot" so what do I know!

[Adrian_L]

Agreed. It simply defies the laws of physics.

[ptjones]

I have mentioned this before, but to get the best MPG's on the HWY you need to get the ICE up to operating temp. of +202*F.  With the ScanGauge you can watch WT and compare it to your average MPG's going down and up. If you don't go fast enough the ICE never gets that HOT!  This is one of the reasons Grill Covers work by getting the ICE up to operating temp and doing it quicker. Even with Grill Covers on it takes me about 15miles to get to operating temp. and can watch my average MPG go down until I reach it. Then it  starts going back up and quiet often I will end up with same MPG's I started with for the trip. (low 50's). :shift: 

 

Paul

[ScubaDadMiami]

You can surely bet that I did the overwhelming majority of my 5,400 mile trip to New England and back on Eco Cruise. I would not even fathom to consider manual driving for such a distance. It would take too much focus and work, and I am willing to bet that there would not be much of a difference in the fuel economy over such long runs when using one method or the other with a non-superhuman driver.

 

When I am local, I make highway runs for up to about 30 minutes or so without cruise control of any kind, because I can read the road (hills, bridges, overpasses) and adjust accordingly. I get better MPG when I fly these shorter runs manually, but I have to do more work to make that happen. For these shorter distances, it is not the big deal to focus on pedal management.

 

There is probably a line that is somewhere between, and where that comes out depends on the tolerance of the driver. It's all good. :thumbsup:

[Jus-A-CMax]

:clapping: Grill covers, eco-cruise long distances, ac for 100+ heat...u CMaxer drivers are whimps :drop:
 

:victory:  & :flyaway:

[C-MaxSea]

........... For these shorter distances, it is not the big deal to focus on pedal management.

 

There is probably a line that is somewhere between, and where that comes out depends on the tolerance of the driver. It's all good. :thumbsup:

Totally agree, and we are on the extremely lazy side of that equation; if the traffic is moving, we are on ECO Cruise within a mile of the on-ramp fang. ;)

 

 

Hey Jus, when are you going to show us that run of 18 - 800 mile tanks?  or was that 23 - 800 mile tanks?  Real, every day urban/suburban 60 MPG dragon slaying !!!  Am I going to have to 'shout you out' !!!  (not here, but somewhere in the 'city' driving threads)  Pretty please.

 

Nick

Edited September 7, 2014 by C-MaxSea

[Kelleytoons]

Just to add some of my own data to this discussion, we went on a two-hour trip 140 mile trip today where our average speed was around 68-70 mph and I got exactly 44.9 mpg both ways using Ecocruise almost exclusively (only two or three times did traffic cause me to brake out of it and maneuver until I could turn it on again).

 

Average outside temps were in the 90's and the inside A/C was set for 73 degrees and three indicators of fan.  Played music and used NAV the entire way as well (not sure how much, if any, that would affect mileage).  Wind speed was 12 mph the entire trip at a crossbreeze (according to my phone weather info) and mostly sea level with gentle hills and valleys (typical Florida landscape).

 

I'm guessing I could have done better with Paul's techniques but it made for an easy drive and I kept to the posted limits (usually 70 mph but several short 60 mph stretches).  Traffic for the most part was also typical Florida, which is to say half the folks were going MUCH faster than I (and the speed limits) was and half were going slower (the older folks -- and *I* am one of those).  But there was enough room for the former to pass and for me to pass the latter.

 

Averaging close to 45 mpg on a fast highway drive to me is better than good -- I suspect in the winter I'll be able to get closer to 50 mpg but if I never get any better I'll be happy).

Edited September 7, 2014 by Kelleytoons

[ptjones]

P&G and Drafting isn't for everyone, but it's worth about 4mpg. Keeps me from being board on long trips. :shift:

 

Paul

[Jus-A-CMax]

Totally agree, and we are on the extremely lazy side of that equation; if the traffic is moving, we are on ECO Cruise within a mile of the on-ramp fang. ;)

 

 

Hey Jus, when are you going to show us that run of 18 - 800 mile tanks?  or was that 23 - 800 mile tanks?  Real, every day urban/suburban 60 MPG dragon slaying !!!  Am I going to have to 'shout you out' !!!  (not here, but somewhere in the 'city' driving threads)  Pretty please.

 

Nick

 

I have taken a job as Consumer ReportToaster Reviwer so I need to tow the Eastern Collectivist doctrine that what you say IS NOT POSSIBLE, 37MPG is it.

 

.wait.

 

.thats better...sorry, I had to let the smoke clear...*cough*....ah....nothing like free smoke from the government.....

 

...As I was saying, yeah, I need to tow the Party Line, for the people and not the capitalist.....*smoke is good......oh yeah.....when is my paycheck coming again, Toaster Review Company?!?!?

[HPRifleman]

For those that may not understand some of the highway mileage techniques mentioned, here is a picture of one application.

 

 

1) Set the left screen to Empower.

2) Run the ICE enough to raise the indicated battery charge level to almost full.

3) Moderate the throttle so the white part of the load display (far left) is only slightly above the blue battery envelope. Keep the engine running. Don't let it go into electric. This will take some work and your right foot might get tired.

 

When all of this is working you can get an instantanous mileage reading as shown in the picture (60MPG) depending on conditions. Provided the road is flat and you don't come across traffic, you can keep this up for a while. Remember that if the ICE load falls inside of the battery envelope, the ICE will shut off and you will be running on electric only. This may seem great but as soon as the battery charge level drops and the ICE restarts the instantaneous mileage will drop. Then, it will take more work to get back to the state you were in before.

[Jus-A-CMax]

...jus stick it in eco-cruise and BLIP that pedal. Easy peasy.

[SnowStorm]

At 55 and "Provided the road is flat and you don't come across traffic", Eco-Cruise will do the same thing with no work at all.  I've seen it many times.  I don't understand why this method is considered a "highway mileage technique" as if you must do this to get better mileage.  Then on the other hand we should P&G to get better mileage which constantly takes you in and out of EV.  I'm confused.  I'm not trying to be difficult (maybe it comes naturally!) but I don't understand why on one hand this "ICE Only" mode gives better mileage and on the other hand P&G is better (I mean better than Eco-Cruise).

 

However, if you can get 60 mpg long term, flat road, no wind, no drafting at 55 mph, then I'm impressed.  I've never seen over 55 mpg - and hardly that.

[scottwood2]

For those that may not understand some of the highway mileage techniques mentioned, here is a picture of one application.

 

Highway.jpg

 

1) Set the left screen to Empower.

2) Run the ICE enough to raise the indicated battery charge level to almost full.

3) Moderate the throttle so the white part of the load display (far left) is only slightly above the blue battery envelope. Keep the engine running. Don't let it go into electric. This will take some work and your right foot might get tired.

 

When all of this is working you can get an instantanous mileage reading as shown in the picture (60MPG) depending on conditions. Provided the road is flat and you don't come across traffic, you can keep this up for a while. Remember that if the ICE load falls inside of the battery envelope, the ICE will shut off and you will be running on electric only. This may seem great but as soon as the battery charge level drops and the ICE restarts the instantaneous mileage will drop. Then, it will take more work to get back to the state you were in before.

So if I am reading this right, the ICE is charging up the battery, supplying power to the wheels and the EV mode is also working?  I did not think of this before but the charging motor and drive motors are separate, I think?  

[Adrian_L]

Yes--sometimes the electric drive AND the ICE are both on--and charging the battery. 

 

I'm kind of on SnowStorm's side--I needed a nap after reading Rifleman's instructions (sorry, it sounded like a ton of work) but mainly I question the long term benefits over a 3 or 4 hour journey versus the magnificent ECO cruise.    

Edited September 9, 2014 by Adrian_L

[obob]

P&G and Drafting isn't for everyone, but it's worth about 4mpg. Keeps me from being board on long trips. :shift:

 

Paul

 

I was curious about drafting and read the first couple pages of this thread.

 

FYI - http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1152576/2

 

some quotes from the thread

 

"Mythbusters tested this & found that drafting behind a semi DOES save gas, but they also made a point to say that it should never be done because it's 100% unsafe."

 

"the mythbusters had a dodge magnum if i remember right. At 100 feet they had like a 10% increase"

 

"I was in the trucking business for 42 years retired now but I hated it when a car tailgated me.

I found that if I let my trailer drift over onto the shoulder and throw a few stones that got them off of my tail."

 

"Fuel mileage increased by a ton, around 50% or more if I remember correctly, following about 2 feet behind the semi"

[plus 3 golfer]

So if I am reading this right, the ICE is charging up the battery, supplying power to the wheels and the EV mode is also working?  I did not think of this before but the charging motor and drive motors are separate, I think?  

Not quite. ICE has already charged up the battery and in HPRifleman's example.ICE is not being used to charge the battery further    

 

What is happening is like I stated in a prior post (Ford quote from manual and the graph).  .  MG1 (the generator) and MG2 (the traction motor) and ICE are physically connected via the planetary gear set.  To maintain this negative spit mode operation in the example, the conditions need to be "right" - generally flat or slight downhill terrain, high HVB SOC (algorithm will  run ICE / MG1 very, very little to charge HVB further) and usually the driver needs to control the throttle (speed / load requirements) to enter this mode,  In this mode, the PCM uses MG1 to slow down ICE rpm by operating as a motor (not a generator) and thus speeds up..  Thus, MG1 effectively "bleeds off" rpm from the gear set so ICE can slow down.   ICE rpm decreases to a more efficient operating point given the load requirements.  MG2 always spins proportionately with the wheels. The PCM then controls MG2 to make up any load requirement differences of ICE supplied power by either generating energy (regeneration) or by using energy (traction motor).  Thus, MG2 not ICE makes up minor difference in load like slight speed increase / decrease, like terrain changes (slight up / down hills) and so forth. 

 

The reason the instantaneous FE goes up is that is ICE is running very efficiently at lower rpm and virtually all the energy from ICE is propelling the car and not charging the HVB.  If one has a manual / DSG transmission in another car, it's similar to up-shifting to a higher gear to decrease ICE rpm from the lower gear.  This allows ICE to run more efficiently.  The drawback in a conventional car is that there may be very little torque for acceleration (the engine is lugging) in the higher gear  In the hybrid, this lack of ICE torque is made up by almost instantaneously by  MG2 should one want to accelerate quickly. 

Edited September 9, 2014 by Plus 3 Golfer

[plus 3 golfer]

I was curious about drafting and read the first couple pages of this thread.

 

FYI - http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1152576/2

 

some quotes from the thread

 

"Mythbusters tested this & found that drafting behind a semi DOES save gas, but they also made a point to say that it should never be done because it's 100% unsafe."

 

"the mythbusters had a dodge magnum if i remember right. At 100 feet they had like a 10% increase"

 

"I was in the trucking business for 42 years retired now but I hated it when a car tailgated me.

I found that if I let my trailer drift over onto the shoulder and throw a few stones that got them off of my tail."

 

"Fuel mileage increased by a ton, around 50% or more if I remember correctly, following about 2 feet behind the semi"

I posted this before.

 

[HPRifleman]

At 55 and "Provided the road is flat and you don't come across traffic", Eco-Cruise will do the same thing with no work at all.

 

Not in my experience. Every time I try to use Eco-Cruise I get lower mileage than I do with the manual method of keeping the battery charged and the engine load just above the electric threshold.

[SnowStorm]

Interesting.  Have you ever been able to compare ICE rpm between Manual-Cruise and Eco-Cruise at the same speed and load conditions (battery "fully" charged as you showed it)?  Maybe Eco settles out at a different (higher?) rpm for some unknown reason.  Will try and keep an open mind but still not convinced. ;)

[scottwood2]

Not quite. ICE has already charged up the battery and in HPRifleman's example.ICE is not being used to charge the battery further    

 

What is happening is like I stated in a prior post (Ford quote from manual and the graph).  .  MG1 (the generator) and MG2 (the traction motor) and ICE are physically connected via the planetary gear set.  To maintain this negative spit mode operation in the example, the conditions need to be "right" - generally flat or slight downhill terrain, high HVB SOC (algorithm will  run ICE / MG1 very, very little to charge HVB further) and usually the driver needs to control the throttle (speed / load requirements) to enter this mode,  In this mode, the PCM uses MG1 to slow down ICE rpm by operating as a motor (not a generator) and thus speeds up..  Thus, MG1 effectively "bleeds off" rpm from the gear set so ICE can slow down.   ICE rpm decreases to a more efficient operating point given the load requirements.  MG2 always spins proportionately with the wheels. The PCM then controls MG2 to make up any load requirement differences of ICE supplied power by either generating energy (regeneration) or by using energy (traction motor).  Thus, MG2 not ICE makes up minor difference in load like slight speed increase / decrease, like terrain changes (slight up / down hills) and so forth. 

 

The reason the instantaneous FE goes up is that is ICE is running very efficiently at lower rpm and virtually all the energy from ICE is propelling the car and not charging the HVB.  If one has a manual / DSG transmission in another car, it's similar to up-shifting to a higher gear to decrease ICE rpm from the lower gear.  This allows ICE to run more efficiently.  The drawback in a conventional car is that there may be very little torque for acceleration (the engine is lugging) in the higher gear  In the hybrid, this lack of ICE torque is made up by almost instantaneously by  MG2 should one want to accelerate quickly. 

Thx for the great explanation.  I love all the tech in this car.   :love_shower: 

[ptjones]

I was curious about drafting and read the first couple pages of this thread.

 

FYI - http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1152576/2

 

some quotes from the thread

 

"Mythbusters tested this & found that drafting behind a semi DOES save gas, but they also made a point to say that it should never be done because it's 100% unsafe."

 

"the mythbusters had a dodge magnum if i remember right. At 100 feet they had like a 10% increase"

 

"I was in the trucking business for 42 years retired now but I hated it when a car tailgated me.

I found that if I let my trailer drift over onto the shoulder and throw a few stones that got them off of my tail."

 

"Fuel mileage increased by a ton, around 50% or more if I remember correctly, following about 2 feet behind the semi"

The best compromise for me is about 50ft. and the amount of improvement is dependent on the direction of the wind. Probably 2-4mpg improvement. Drafting is beneficial 55mph up, especially 80mph LOL. :) 

 

Paul 

[Adrian_L]

I think drafting is a great idea, provided the driver doesn't violate the 2 second rule. 

 

At 60 miles/hour, you cover 176 feet in two seconds, so that is the minimum safe distance behind a semi.