driving close to 62 mph

[milleron]

I went to work this morning, a Saturday, with little traffic on the road. I got in the right lane and set the cruise to 60. The car went into and out of EV several times during the 10-mi trip that's mostly freeway. What I noticed was that every time, the ICE turned on, the instantaneous mpg would be very close to 20. It would gradually inch up until it got to around 35, when it would go into EV again. The overall mileage for that trip was about 38 mpg, just slightly better than I'd have gotten in my ten-year-old 240hp Accord V6 coupe driving 65-68 all the way.

 

After work, I took a jaunt on the freeway. This time, I was careful to set the cruise to 64 to prevent EV mode from cutting in an out. The instantaneous economy readouts then exceeded 40 for most of the trip -- 30 uphill and 50+ downhill, as I'd expect from a mid-size family car. The mileage for the 26-mile trip was 44.

 

When the car cannot continue in EV because of a low SOC, I'm deducing that the mileage is dreadful because the CVT has to rev high to recharge the HV battery. So when the car spends 3/4 of it's time at 20mpg and 1/4 in EV, the results can be quite disappointing. When you drive it fast enough that the ICE stays on, the SOC remains high enough that the ICE is not tasked heavily with recharging the HVB, and EV can take over with a high SOC on exiting the highway, the results seem better.

 

Is my explanation correct?

Have any of the rest of you experienced the same phenomenon?

 

Ron

[rjent]

That explains some behavior I saw yesterday. I only have about 200 miles on now, so I have no baseline, but I do have a 70 mile, oneway, trip to make this coming week. I will experiment ..... :)

[jeff_h]

Is my explanation correct?Have any of the rest of you experienced the same phenomenon?

 

This is the reasoning of lolder and acdii (and others), with the concept that when using EV more, the ICE has to come on eventually to charge the HVB back up, and when it does the MPG suffers more than if you just set speed at 65 MPH and kept the SOC high, yielding a steady MPG of about 40 or so.

 

I agree with this when most of the terrain is level, however when not level (various rolling hills, etc) I think the slower speed that mixes in the EV more tends to come out slightly better, at least in my comparison. This is why I posted in a couple other threads that it would be a good idea for an owner that does have this type of terrain and repeatable route (such as the daily grind) to try it at different speed settings on different days (assuming weather and traffic conditions are similar) to see which method yields the better MPG for you and report your results.

Edited April 27, 2013 by jeff_h

[lolder]

I think Ford shot themselves in the foot a little raising the EV speed to 62 to game the EPA highway test. That test resembles only a small percentage of highway trips and none at steady 60 mph + speeds. The Fords are 20 % heavier and more powerful than Prii and get 20 % less mpg. You can look only at the weight and horsepower of a modern car and predict the mpg unless the manufacturer muffed the design. The Fords are good designs. After 40 mpg is achieved, there are diminishing returns in economy. As an example, loaded Fords weigh about 2 tons and get 40 mpg., Prii weigh about 1 1/2 tons and get 50 mpg. The vehicle that won the "X" Prize for a 100 mpg. car weighed less than 1/2 ton ( 800 lbs.). Toyota hit a home run with the first Prius and has only incremental improvement since. Most hybrids are state of the art and only large technology gains are going to improve them. The ICEs are about at the maximum thermodynamic efficiency for today's metals and fuels. The 2013 FFH's will probably beat the EPA numbers in the warm weather and approach 50 mpg ( you can get 60 mpg in a Prius in the same benign conditions )

My 2010 is the most comfortable highway car I've ever driven and it holds the road like it's on rails. Around town it is almost soundless.

[acdii]

I went to work this morning, a Saturday, with little traffic on the road. I got in the right lane and set the cruise to 60. The car went into and out of EV several times during the 10-mi trip that's mostly freeway. What I noticed was that every time, the ICE turned on, the instantaneous mpg would be very close to 20. It would gradually inch up until it got to around 35, when it would go into EV again. The overall mileage for that trip was about 38 mpg, just slightly better than I'd have gotten in my ten-year-old 240hp Accord V6 coupe driving 65-68 all the way.

 

After work, I took a jaunt on the freeway. This time, I was careful to set the cruise to 64 to prevent EV mode from cutting in an out. The instantaneous economy readouts then exceeded 40 for most of the trip -- 30 uphill and 50+ downhill, as I'd expect from a mid-size family car. The mileage for the 26-mile trip was 44.

 

When the car cannot continue in EV because of a low SOC, I'm deducing that the mileage is dreadful because the CVT has to rev high to recharge the HV battery. So when the car spends 3/4 of it's time at 20mpg and 1/4 in EV, the results can be quite disappointing. When you drive it fast enough that the ICE stays on, the SOC remains high enough that the ICE is not tasked heavily with recharging the HVB, and EV can take over with a high SOC on exiting the highway, the results seem better.

 

Is my explanation correct?

Have any of the rest of you experienced the same phenomenon?

 

Ron

This is pretty much spot on with what I found too. On roads that are hilly by me, if i keep it above 60, and play the game of speeding up going downhill since my SOC is high, I bleed off the excess going up the next hill while keeping it on ICe at all times. Then and only then was I able to see the instant show 40+. In town driving I found that if I could keep it above 50% charge, using EV occasionally I was able to keep the ICE above 40 as well. If I drove 45 MPH with few signals, I could see up to 50 MPG, sad part, I can see the same in my 2010. That .5 liter helps a lot in the 10. If Ford had kept the 2.5 in the Fusion, It would probably actually get 47 Interstate.

[milleron]

Today, I had another weekend work commute with mostly-deserted freeways. I put the cruise on 64 so as to go as slowly as I could without engaging EV on the freeway for about 12 miles. The trip also included about 2.5 miles of streets at 60°, and all the FFH could do was 35.9 mpg. Moving between hospitals after that, I came 6.0 miles on streets, only 2.8 miles of which was done with the ICE. 53% of that short trip was EV, and it came out to only 37 mpg.

I'm noticing in city driving that when the ICE is on, the instantaneous mileage indicator is virtually never greater than 20 mpg, and it spends most of the time closer to 15 mpg. I haven't had it long enough to get severely depressed, but it's getting worse rather than better, in spite of babying it and getting brake and acceleration scores close to 95%. Is something wrong with this car??

Edited April 28, 2013 by milleron

[keybman]

I wholeheartedly agree with jeff_H with the idea of experimenting and finding what works for you in your particular driving scenario.

 

From what you have described, my suggestion would be to try not using cruise control.

 

For my daily work commute, I have not found the cruise to be economical, MPG-wise. It tends to spend much of the time as has been described - in ICE trying to charge up the SOC. I then end up spending my driving time pressing "+" or "-", trying to improve the plummeting MPG and falling leaves.

 

What does work for me is the Pulse and Glide. On city streets or on the highway, I steadily accelerate to just above the speed limit, then back off the accelerator. The FFH kicks into EV mode and maintains for a couple minutes. Then, I will lightly touch the gas pedal to maintain speed, as needed. Eventually, the EV needs to charge, and I steadily accelerate (usually only takes 5-6 seconds) and repeat the whole process. This works for speed limits up to 60 MPH and since I am maintaining speed, I don't totally look like a hypermiling Prius driver (no offense intended to slow drivers in the right lane!).

 

Now if I were going on a road trip with open highway driving (65-75 MPH speed limits) and a long way to go, I think that is where I would be tempted to use my cruise, using the method as others have described.

Edited April 28, 2013 by keybman

[rjent]

I have very little experience so far, but my observation to this point is NOT to try to drive it using battery. I know that sounds like an oxymoron, but I think that if the battery gets low to really low because we are "forcing" it into EV, the engine works it's tiny little ass off trying to get the battery back to half charge. If the battery charge is high, you see the EV helping the ICE and the instantaneous MPG be between 30 and 50.

 

Anyway, just my limited viewpoint so far...... I expect to become a real expert in a few days ... :)

[milleron]

Pulse & Glide tomorrow, then. I guess it's not realistic to give up yet, but after waiting for this car for 4 months with great enthusiasm, the disappointment in the worsening mileage has been so great that the enthusiasm has nearly died. It's a lot of work to baby and coddle this car, and I knew that going in, but I anticipated a reward in the form of economy and the satisfaction of knowing that I'm not dumping as many tons of CO2 into the atmosphere. So far, it's been a lot of work for no reward. The very first evening I drove it, I got 40.5 and 43 mpg on trips of 10 and 14 miles, but I haven't been able to come close to those figures since then. I VERY much appreciate the thoughtful suggestions you guys are giving me, and I'll try them all.

[tombarker13ffh]

In a 55 mph zone I will get to 60 mph, let off gas to engage EV, lightly apply the pedal to keep -most- of my speed until I've run out of SOC and I will have dropped to nearer 50mph and then -lightly- accelerate to charge the battery and regain speed until I've reached 60mph again. I will coast downhill or accelerate sharply downhill to gain speed, depending on SOC and speed. It seems like a lot of work but its not really and I get 50+mpg doing this on two-lane highways. On 65mph interstates I will set cruise at 64mph, but most often its produced mid-40s mpg numbers instead. Of course, all of my commutes include some city driving where I'll only use gas to get up to 35mph and EV the other 90% of the time. This helps keep my mpg results in the 50s, sometimes 60s. I'm going to finish this tank probably tomorrow with about 530 miles and 47.5 mpg. Not as good as last tank's 49-something...

[tombarker13ffh]

I have also found that setting cruise at lower speeds, like 50-55mph that the car will drain the battery much faster than I would like and uses way too much gas to charge it back up. I can't bring myself to let it stay on cruise. It'd probably get low 40s if I let it go.

[acdii]

In a 55 mph zone I will get to 60 mph, let off gas to engage EV, lightly apply the pedal to keep -most- of my speed until I've run out of SOC and I will have dropped to nearer 50mph and then -lightly- accelerate to charge the battery and regain speed until I've reached 60mph again. I will coast downhill or accelerate sharply downhill to gain speed, depending on SOC and speed. It seems like a lot of work but its not really and I get 50+mpg doing this on two-lane highways. On 65mph interstates I will set cruise at 64mph, but most often its produced mid-40s mpg numbers instead. Of course, all of my commutes include some city driving where I'll only use gas to get up to 35mph and EV the other 90% of the time. This helps keep my mpg results in the 50s, sometimes 60s. I'm going to finish this tank probably tomorrow with about 530 miles and 47.5 mpg. Not as good as last tank's 49-something...

^this^ I can't do it in the 2010 since it doesnt EV above 45, but the technique is the same. Didn't work well at all in the 13 I had though, even with the Ford tech doing it in an extreme manner he was only able to achieve 44, and that was after the car was fully warmed up and about 100 miles of driving. However, this is the correct technique to get the most out of each drop of fuel, and it does not need to be just a Hybrid, same thing works in my Flex.

 

Milleron, in your case, I am just wondering if its battery related, so see what happens if you can keep the charge level at or above 50%. Stay off cruise, and feather the pedal instead to hold speed while watching the instant readout, carefully I might add, eyes on the road! With some practice you will be able to hold a nice steady speed within a few MPH while getting higher MPG gains. The cruise control is OK for long trips, but YMMV more than manually controlling the speed as has been noted by a few other owners now who have taken long trips. With cruise they are seeing about 38 or so at Interstate speeds.

 

With warmer weather coming in, now is the time we will find the weak ones cropping up. Those that performed not so well in winter, that dont improve most likely have an issue, but those that do improve, like Nick's did, he got 45 in it the other day! :woohoo: dont have an issue, it was just the cold and gas blends.

[milleron]

Thanks, acdii. What do you mean by "gas blends?" Ethanol percentages?

[acdii]

Winter blends have additives that kill gas mileage. What the reason is, I dont know, but it sucks.

[rico567]

Winter blends have additives that kill gas mileage. What the reason is, I dont know, but it sucks.

The reason is the EPA regs on the fractions of hydrocarbons that go into the gas. Effectively you have "Winter" and "Summer" gas. The reason for this is the higher summer temperatures producing more pollution from evaporation. So in the Winter, there are more cheaper "junk" fractions (like butane) put in the gasoline, while the Summer blends are higher quality mixes of hydrocarbon chains that are more stable (i.e., don't evaporate as much). Comparing blends of gasoline is a lot like comparing the other factors involved with Winter vs. Summer driving: Winter means lower mileage because of cold starts, Summer because of A/C use, etc. No way around it.

[acdii]

HAHAH so they dump the cheap stuff on us in winter....AND charge more for it. those bastriches

[GrySql]

More about fuel blending is here.

Want to know why gasoline is so expensive, look here. Let me give you a hint ---> Regulatory constraints

More fun reading about the Blendwall.

 

Now, back to whatever the topic was..... :headscratch:

Edited May 1, 2013 by GrySql

[milleron]

Following some suggestions given here, I've managed a ten-mile trip OFF freeway of 45.5 mpg, so I'm hoping that indicates that nothing's seriously wrong with the car. Perhaps it'll improve a couple of mpg with break-in completed, although I'm far from that point.

 

Thanks, GrySql for some very interesting reading.

 

Ron

[Kwilli]

Thanks for posting these tips. My highway driving has returned atrocious numbers. In the city I'm doing really well. Can't wait to try the new techniques.

[jeff_h]

Thanks for posting these tips. My highway driving has returned atrocious numbers. In the city I'm doing really well. Can't wait to try the new techniques.

 

That;s because you are in Oklahoma, where highway driving has a headwind no matter where you're driving...

[corncobs]

No no no not head winds again I will be driving thru Oklahoma on Monday I was hoping for some tailwind going east.

[acdii]

OOOOKLAHoma where the wind comes blowing in your face!!!

[hybridbear]

I have been wanting to try this on a nice stretch of interstate here since we have lots of rolling hills. I want to wait for a nice 60+ degree day with minimal wind though and we can't seem to get rid of winter. No snow fell at our house last night, but just 40 miles south of the Twin Cities and about 15 miles east there was 15-20 inches of snow last night with more falling during the day today. Winter just won't quit!!!

 

The more we drive the more I believe that highway cruising above 62 MPH is better than cruising at 55 or 60 MPH. For short highway trips within the city I know avoid using cruise and try to keep it out of EV mode. Or we really just try to avoid the highway all together and take city streets everywhere now since those get the best mileage and are also less stressful than getting on and off the highway, even if it does take a few extra minutes. Since both my wife and I enjoy our time in the car we don't mind spending a few more minutes in it. We also find ourselves going for extra little drives all the time to spend more time in the car.

 

 

This is the reasoning of lolder and acdii (and others), with the concept that when using EV more, the ICE has to come on eventually to charge the HVB back up, and when it does the MPG suffers more than if you just set speed at 65 MPH and kept the SOC high, yielding a steady MPG of about 40 or so.

 

I agree with this when most of the terrain is level, however when not level (various rolling hills, etc) I think the slower speed that mixes in the EV more tends to come out slightly better, at least in my comparison. This is why I posted in a couple other threads that it would be a good idea for an owner that does have this type of terrain and repeatable route (such as the daily grind) to try it at different speed settings on different days (assuming weather and traffic conditions are similar) to see which method yields the better MPG for you and report your results.

[Eliotmal]

Don't trust gas milage on short trips (~10 miles), it is too short for things to average out. Use Echo Cruise. Don't try so hard, just drive about 5 mph over the limit and you should do fine. I think all the people trying to force good milage, especially on short trips, are actually lowering their MPG. I find weekends when I drive hundreds of miles on state roads my MPG goes up, on week days when I commute ~10 miles to work my MPG goes down.

[acdii]

Don't trust gas milage on short trips (~10 miles), it is too short for things to average out. Use Echo Cruise. Don't try so hard, just drive about 5 mph over the limit and you should do fine. I think all the people trying to force good milage, especially on short trips, are actually lowering their MPG. I find weekends when I drive hundreds of miles on state roads my MPG goes up, on week days when I commute ~10 miles to work my MPG goes down.

This is true, it isnt until I am about 9 miles into my trip that I start to recover the lost miles from cold start and acceleration. It takes about 5 miles before the car settles down to where I can stay light on the throttle and hold the speed, and its not just the FFH, but also the Flex that does it. Just drive it as any other car the first 5 or so miles, then go hybrid on it. Dont get crazy stupid racing around though.