Best Highway Cruising Speed for MPG's

[Jus-A-CMax]

Drafting...its inevitable to get those chips on the windscreen, I scored a couple. Also you leave yourself open to :airquote: el-weirdo truckies - one started acting the fool by slowing down to a ridiculous 45 mph on a 70 mph freeway because I was drafting him and I recall I wasn't even as close. Other than that, they are pretty good.

 

Now manual vs eco = Manual would win but you're working hard at it. I've done > 500 miles manual and it was not a HUGE difference at the end - something stupid like 3 MPG difference at end. Thats say 43MPG > 500 miles vs 47MPG. 

 

The smart thing to do is to know when to call which drive mode - eco, manual, and when to BLIP.....you young grasshoppers  :baby:

Edited September 10, 2014 by Jus-A-CMax

[ptjones]

As you can see from Plus 3 Golfer anything more than 100ft back is useless as far as Drafting is concerned. Have been drafting since 74 (The Great GAS Crisis) with no accidents. Drafting is only for those willing to pay attention 100% of the time what is going on around them and ready to react immediately. IMO :) 

 

Paul

[kaptnk228]

Wow!!  I wish I could get above 40 mpg at 65 mph.  We run on cruise control and push the vehicle to use the battery when I see it charged.

 

Here is what I remember about my engineering design vehicle course.

 

There are two different types of loses:  Rolling and aerodynamic.   At around 60 mph and above aero starts to exceed rolling due to the increase according to the square of the velocity.  The cod of drag is built into the vehicle.  The C-Max has a high celing and most likely not the lowest projected frontal area.  I hated the Toyota corolla's small size that I had difficulty (only 6ft tall) getting in and out.  I will take the C-Max any day.

 

So the faster we go, the more fuel we use.  Some suggest increasing the tire pressure which does help but you don't want to exceed the max or even get too close to it IMHO.  The Michelin tires that come with the vehicle are the best out there.  Going to another make might make things worst.  At 70 mph, we get 35-37 mpg.  Again tail winds and head winds do and will effect your numbers along with hills.  Remember to check pressure in the cold weather as it will drop down in winter and increase in summer.

 

Nissan post amazing numbers with their CVT's even with what appears to be an old engine design.  Ford uses a eCVT.

 

At high way speed there are only small gains from the hybrid and mpg largely depends on the ICE.  Therefore the best engine is the Mazda Sky with their 14:1 CR  Efficiency is directly proportional to the Compression Ratio period.  It may be possible to get 50 mpg at 70 mph with this engine.  Tests with this engine in other hybrids showed great or outstanding results.  The Ford approach with a different cycle and a CR of 12.3 falls short here.  Mazda typically sell this engine with a CR of 13:1 but they have run it with 14:1 CR.  A small diesel engine may help also.  Gas seems to cost a lot less these days than diesel fuel.

Edited January 17, 2015 by kaptnk228

[wb8nbs]

Wow!!  I wish I could get above 40 mpg at 65 mph.  We run on cruise control and push the vehicle to use the battery when I see it charged.

 

Here is what I remember about my engineering design vehicle course.

 

At high way speed there are only small gains from the hybrid and mpg largely depends on the ICE.  Therefore the best engine is the Mazda Sky with their 14:1 CR  Efficiency is directly proportional to the Compression Ratio period.  It may be possible to get 50 mpg at 70 mph with this engine.  Tests with this engine in other hybrids showed great or outstanding results.  The Ford approach with a different cycle and a CR of 12.3 falls short here.  Mazda typically sell this engine with a CR of 13:1 but they have run it with 14:1 CR.  A small diesel engine may help also.  Gas seems to cost a lot less these days than diesel fuel.

 

The Mazda engine is also, like Ford's an Atkinson cycle design which spoils the compression ratio advantage.

[Kelleytoons]

Here in Florida I've been consistently getting around 42mpg when going 75+, so it's not all that difficult (although it brings down my total mpg average.  Sigh).

[wb8nbs]

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. 

 

So you're saying never kick in the electrics? You might as well have bought a Focus for $6k less and not have the weight of the batteries. I had an 09 Focus, my personal  best was 46 MPG on a 400 mile trip to northern Wisconsin.

[ScubaDadMiami]

So you're saying never kick in the electrics? You might as well have bought a Focus for $6k less and not have the weight of the batteries. I had an 09 Focus, my personal  best was 46 MPG on a 400 mile trip to northern Wisconsin.

If you only drive highway all the time, then there would be choices that are just a good as the C-MAX, some maybe better, if all that you are doing is considering fuel economy and the initial cost of the vehicle. However, there can be other trade-offs that could also factor into the final evaluation, such as space in the vehicle and comfort. There is a vehicle out there for everybody, and, depending on the circumstances, that doesn't always come down to the same factors.

 

I know that I really appreciated having all of that extra space for gear, during my cross country trips in my C-MAX, especially when I was getting great fuel economy for those trips. I also liked riding up higher off of the road than I would in a lot of other cars that also get great fuel economy. I liked the ease of getting into and out of my C-MAX. Things like that are something that I consider just as much as I consider the importance of the fuel economy.

 

It's all a question of the type of driving that you end out doing. I like having a vehicle that gets 50-60+ city and 45-50+ highway while holding a great deal of cargo or five passengers. If that is not your top priority, then you should get what works best for what you do.

Edited February 2, 2015 by ScubaDadMiami

[scottwood2]

If you only drive highway all the time, then there would be choices that are just a good as the C-MAX, some maybe better, if all that you are doing is considering fuel economy and the initial cost of the vehicle. However, there can be other trade-offs that could also factor into the final evaluation, such as space in the vehicle and comfort. There is a vehicle out there for everybody, and, depending on the circumstances, that doesn't always come down to the same factors.

 

I know that I really appreciated having all of that extra space for gear, during my cross country trips in my C-MAX, especially when I was getting great fuel economy for those trips. I also liked riding up higher off of the road than I would in a lot of other cars that also get great fuel economy. I liked the ease of getting into and out of my C-MAX. Things like that are something that I consider just as much as I consider the importance of the fuel economy.

 

It's all a question of the type of driving that you end out doing. I like having a vehicle that gets 50-60+ city and 45-50+ highway while holding a great deal of cargo or five passengers. If that is not your top priority, then you should get what works best for what you do.

At the auto show I went and looked again at the Honda Fit.  This was on my list of cars.  I like the design of the car.  Great interior use and great FE.  I can also get in and out of this car pretty good.  I really like the car but the feel is very different from the C-Max.  I feel safer and more like I am in a premium vehicle in the C-Max.  

[plus 3 golfer]

So you're saying never kick in the electrics? You might as well have bought a Focus for $6k less and not have the weight of the batteries. I had an 09 Focus, my personal  best was 46 MPG on a 400 mile trip to northern Wisconsin.

It depends on conditions.  The electrics can help with FE to an extent on the highway but not like in city / suburban driving .  In general, at highway cruising speeds ICE in hybrids and non-hybrids should be operating at high efficiency.  Thus, FE can be similar in both at high speeds.  In either, one can employ hypermiling techniques and increase FE.  Since the hybrid can store energy, it should have an advantage over a non-hybrid especially in rolling terrain where road load varies which may be offset by the increased weight of the hybrid over the non-hybrid.

 

But, a $6 k price difference is hard to make up in a hybrid even with a $4 gas price.  $6 k buys 1500 gallons of gas.  At 30 mpg in a non-hybrid and 40 mpg in a hybrid, that's a simple payback at 180,000 miles (no time value of money) to break even.  Even if the numbers were 35 mpg vs 50 mpg, the payback is still high at 175,000 miles. But, as others have said there are other reasons to buy the C-Max over a non-hybrid.

Edited February 2, 2015 by Plus 3 Golfer

[drdiesel1]

I hate driving econoboxes. Most hybrids are econoboxes. They have a terrible ride. Very uncomfortable

and the road noise is unbelievable. The overall size is small and makes me feel vulnerable in traffic.

 

All my previous non hybrid cars were domestics and carried a price tag around 25K. They were all loaded

with high trim levels. The average price over the years never changed much. I had 2 Prii and hated them.

(see econobox above) The C-Max came along and changed all that. I only paid 28.5K for my 303A Energi

and it's a pleasure to drive. The FE is just the icing on the cake. It's not always about payback for buying a

hybrid car. Comfort and safety are more important to me.

 

I get paid back when I sign the paperwork and enjoy saving as I drive it. :happy feet:

Edited February 2, 2015 by drdiesel1

[Kelleytoons]

+1 (and ScubaDad).  My feelings exactly -- I just love driving it and the FE is a sweet bonus.

[SPL Tech]

I am easily getting over 40 MPG in city driving (hand calculated), yet when taking long Texas highway road trips when I must push 75 mph I only get 34.5 on the average. I have been trying to find a -magic- highway speed to get to my appointments on time and not waste efficiency. I don't seem to have found the sweet spot on this. I am in Texas Hill country primarily making continuous ups and downs and running lots of A/C lately. I have tried 68 MPH which seems to push me up to around 36.5 to 37 MPG's. I will also 'pedal shift' the car into e-mode on downhills, but I can get sloppy on this on 6 hour trips.

Anyone got a compromise speed they've found to get somewhere relatively fast. I cannot drive 55 MPH, I know this is where this vehicle shines, some places I drive out here the speed limit is 80... The semi-trucks are doing all of that.

Thanks

Aerodynamic drag increases as the square of velocity, and the fuel consumption increases exponentially in a trackable fashion. There is no "sweet spot." Your MPGs will decrease in an exponential manner as the speed increases, and you can track this over a chart quite easily. There is no special key you're missing here, you just need to trade MPG for time to the extent you feel appropriate. As the speed increases, the MPG will decrease in a very predictable and calculable manner.

 

And no the vehicle does not shine at 55 MPH. The most fuel-efficient speed of any vehicle is probably around 15-25 MPH. You could probably get over 65 MPG at that speed. From there, as the speed increases the drag increases as the square of the speed increase, just like I said in the first sentence.

Edited February 4, 2015 by SPL Tech

[wb8nbs]

The most PRACTICAL fuel efficient speed is whatever is required to get your transmission to shift into overdrive. On my 09 Focus that was about 42 MPH.

[ptjones]

Using A/C can hurt your MPG's 2-3mpg or more. With temps 70-80's I have been able to 47mpg on the I-10 FWY with my aero mods and some drafting. I take advantage of P&G when I can too. At 55mph I can get around 55mpg and 40mph around 70mpg.  At 30mph should get about 80mpg and going any slower gets to be time prohibitive.

 

The most PRACTICAL fuel efficient speed is whatever is required to get your transmission to shift into overdrive. On my 09 Focus that was about 42 MPH.

CMAX uses CVT(continuous variable transmission) so there is no over drive. You do want to be in high gear and not low. :)

 

Paul 

Edited February 4, 2015 by ptjones

[SnowStorm]

.... There is no "sweet spot." ....

 

And no the vehicle does not shine at 55 MPH. ...

I tend to agree about the "sweet spot" - but of course you must define it first:

1. Most "optimum" compromise between MPG and MPH - totally personal - define any value you like.
2. A "magical" speed where either speeding up or slowing down results in lower mileage.  This is the one we don't buy.
3. A "discontinuity" in the MPG versus MPH graph where an increase in speed causes a larger than expected decrease in MPG due to the hybrid system switching modes (see below).  If this happens, one might define the "sweet spot" as being just below that speed.

For #3 above, I'm thinking of the speed where the car stops going in and out of EV and the ICE stays on.  I drive a lot of Interstate with "rolling hills" and at 65 MPH the car uses EV quite often.  But at 70 MPH the ICE is on almost all the time.  My impression is that the drop in mileage from 65 to 70 is larger than you would expect - but I have no real data.  On a flat road my car will just barely keep ICE on constantly at 55 MPH (using cruise control).  At 50 MPH I expect it would constantly go in/out of EV.  Does anyone have any good data or other impressions?

 

As SPL says, you can get far better mileage below 55 MPH.  I have a "test course" I've run a couple of times at about 35 to 40 MPH where I get over 70 MPG returning to the same point and the same SOC on HVB.

 

BTW, hills can be your friend - see this post.

[cheezy]

Several factors are in OUR control, start there; higher tire pressures on eco-tires, quality synthetic oils at just the halfway fill mark on the stick, and ethanol free gasoline will give you an extra 10% with MANY added benefits of NOT having corn in your fuel system.

 

 

http://pure-gas.org/index.jsp?stateprov=FL

 

Forst, locate your ethanol free stations, then find the one that gouges the least. Here in WI we've found the Cenex stores to be the best.

 

Tires; IIRC we have Michelin Defenders on the Prius from Discount Tire, it's a 90K mile tire with a decent warranty/guarantee. Get on their e-mail list for sales and you can grab a set with an $80-100, rebate card, free 6 mo. financing, 5K tire rotations are gratis. 

 

Otherwise, it sound like EcoCruise at about 67 mph...Cool.  A good wax job too. And a white one, cuz they're faster.  

[Telesrjyje]

I have an 06 powerstroke that I want to slowly add some power to. I know I have to open up the exhaust a bit so she can breathe. But ebeing from CA, we have smog to deal with now. What is a good exhaust system for my truck that is still smog legal. I know I can do a cat delete, but I was thinking turbo back. Do I get one that gets rid of the muffler? Can I still smog with no muffler?

 

Thanks

Dima

[ptjones]

On my PowerStroke 2006 I put on Airaid air filter system and Hyperteck programmer on second setting and got up to 21.5 mpg going 65-70 mph.  Averaged 20+ on the HWY. :)

 

Paul