Does EV+ Actually Help?

[SPL Tech]

So the EV+ mode works by lowering the threshold for turning the ICE on when in EV mode. Okay got it. But how does that actually help improve MPG? The problem is that energy is not free. If you drain the battery more this trip, you start with that much less battery next trip which means more ICE time to charge the battery next trip. Either way, the energy has to come from somewhere.

So it seems like all EV+ really does is "borrow" energy from your next drive to use on your current drive by running the battery lower than normal, but I dont see how that would ever improve MPG as, again, the ICE will just have to run that much longer on your next drive.

The only scenario I can see where this would help is if you use EV+ to climb the last stretch of a very long hill—a hill that is long enough to fully recharge your battery on the way down. Then on your next drive, you spend that much less time wasting regen power because your battery is full. But this is a scenario that does not apply to most, so how does EV+ really help?

 

[plus 3 golfer]

It seems to me the reasoning might be that since ICE generally needs to run upon start up from a cold start, why not drain the HVB with EV+ and then run ICE at higher load to charge the HVB during its next warm up. This likely results in better ICE efficiency and faster warm up to reach closed loop operation.  It's not only about FE but also about emissions.  So, EV+ could help increase overall FE and reduce emissions.  

 

Also, I think you mean that EV+ "increases" the threshold for turning on ICE.  The bar for turning on ICE when in EV+ moves higher allowing EV mode to be used at higher loads and for longer periods.  
 

[scottwood2]

I wondered the same thing as first.  But as Plus 3 Golfer said starting out with a low battery is better when cold.  Might as well use the energy while the ICE is warming up to charge the battery.  Kind of a cool idea.  I just noticed that my EV+ mode seems to be coming on sooner than in the past.  Not sure why but it can help.  

[Bill-N]

So the EV+ mode works by lowering the threshold for turning the ICE on when in EV mode....

 

Actually, it raises the threshold.  I.e. the engine will not turn on as soon/easily.

[fotomoto]

 The problem is that energy is not free. 

 

EV+ works great for us Energi owners when it allows us to make it home gas free to a plug to recharge.  Then, we don't have to worry about a gasoline burn first thing on the start up of the next drive.     :)

 

Trivia:  you can force learn an EV+ location by turning the car on/off 11 times in a row.  

[Adrian_L]

For the Hybrid, it is a complete gimmick and I'd turn mine off if I could be bothered.

[homestead]

For the Hybrid, it is a complete gimmick and I'd turn mine off if I could be bothered.

You can turn it off, see page 122 of the user manual.

[ScubaDadMiami]

I am actually running a tank without it right now, and it seems not to reduce my fuel economy at all. Actually, I think that, for experienced drivers, EV+ can actually reduce fuel economy.

 

For example, I live in a high rise condo. I have to drive through a parking garage. If I would use EV+ as I approached my building, there is a chance that I wouldn't have enough juice to reach my parking spot without ICE firing up. On my next trip, I would have to start ICE while still barely moving through the parking garage, crossing our big driveway, and stopping at the driveway's intersection with the street. If cars are coming, I am sitting at that stop with ICE running.

 

On the other hand, if I intentionally do a charge up burn and glide as I approach the condo (either by overriding EV+ or by turning it off), I arrive at my building with a nearly full battery. I am moving so slowly that I hardly use any juice while crossing the driveway, entering the parking garage, and getting to my parking spot. I can then use the full battery for the trip out to the street, and if no cars are coming, I can get up to speed and drive about a quarter mile or more before my first ICE burn.

 

Leaving EV+ turned off allows me to maintain greater control. The only downside is that I can't use quite as much juice at the low end of the SOC. However, the number of times that I would need to do this are so few that I am thinking that I will keep EV+ turned off.

 

BTW, I have used 3/4 of this tank, partly with air conditioning (maybe 15 percent), and I am at 60 MPG, so far. (Remember that, as it gets colder up north, that's when my numbers start to go up.)

Edited November 29, 2014 by ScubaDadMiami

[Kelleytoons]

It seems to me, in general, that EV+ is probably good IF you live in a colder climate.  As others have said, it will allow ICE to come on right away which you need to warm the engine up anyway (before good mileage will start).  OTOH, if you are in a warm climate (or it's summer) then it depends on your driving patterns (as Miami Dad shows).

 

For me I think it's a wash -- doesn't matter either way whether EV+ is on or off, in terms of mileage.  My trips are pretty consistent whether I am going back home (when it would kick in) or out somewhere (where it doesn't).  So I leave it on, just for fun (it's kind of fun when it does kick in to remind me home is right around the corner :>)

[plus 3 golfer]

Here's a press release by Ford on EV+.

 

It certainly appears that Ford's goal is to develop algorithms that "predict and adjust to different driving demands.   “We wanted a vehicle to perform in a certain way when it hit a certain spot,” said Smith."  There is no claim in the press release of improving FE but it gives what customers love - "more driving time in electric-only mode" and bragging rights - “No other automaker seamlessly integrates global positioning and propulsion system control as we have with EV+.”

 

So, EV+ may only be the beginning of altering vehicle operation based on predictive algorithms.  This really is no different than what some drivers do on their own now to improve their FE (for example, kicking in EV mode when the driver deems it beneficial based on their knowledge of the driving demands of their route.)   

 

 

 

 

 

 

[fotomoto]

Here's a press release by Ford on EV+.

 

It certainly appears that Ford's goal is to develop algorithms that "predict and adjust to different driving demands.   

 

 

Ford listen to hybrid <cough, Prius, cough> drivers wishes, concerns, and complaints when developing the CMax.  Things like EV+, better instrumentation (coolant gauge, tach, etc), more room, and a more powerful drivetrain are just some of the improvements. 

 

EV+ also works well for folks who's destination ends at the top of hills.  They can arrive with an empty battery ready for recharging by regen on the coast back down on the next drive.

Edited November 29, 2014 by fotomoto

[plus 3 golfer]

Ford listen to hybrid <cough, Prius, cough> drivers wishes, concerns, and complaints when developing the CMax.  Things like EV+, better instrumentation (coolant gauge, tach, etc), more room, and a more powerful drivetrain are just some of the improvements. 

 

EV+ also works well for folks who's destination ends at the top of hills.  They can arrive with an empty battery ready for recharging by regen on the coast back down on the next drive.

 

Pretty much a given based on Ford's early commercials targeting the Prius V. :)   Get Prius drivers in the showroom touting the C-Max beats Prius V in MPG and sell them on the improvements over the Priis.   If the C-Max was a Prius clone, I wouldn't be driving a hybrid today.

 

Also, given that the amount of energy to be saved with EV+ (if any) is rather insignificant in 1/8 mile for a typical driver, EV+ is more of a "gimmick" as Adrian L says.  I think one would be lucky to average a tenth of a kWh benefit in charging costs (electricity or lost potential energy vs gas) unless one is climbing a very steep hill and then it might be a few tenths of a kWh on average. The maximum benefit would be 70% SOC down to 30% SOC or 40% of 1.4 kWh or about 0.56 kWh. I doubt very few reach 70 % SOC 1/8 mile from home and then drop 0.56 kWh in 1/8th mile.   But IIRC, GM is touting the new Volt (gen 2) as going to have something like EV+.

[RobMax]

Not that I'd use it for such, but the first thing I thought of when learning about EV+ was it's the "Cheating Spouse" option, allowing the driver to sneak home rigged for silent running to either not get caught, or to catch the one at home with the pool boy or baby sitter. LOL

[stevedebi]

It makes sense for the Energi driver, because they can juice up at home. I'm not sure it is that important for the conventional C-Max hybrid. I suppose some of the things folks have said about cold weather apply, but really I'm not sure it is that significant.

[fbov]

EV+ is a prime tool for those playing the hybrid mileage game.

 

The end of most trips, I'm driving at moderate speed through neighborhoods, with lots of turns, hills and stop signs. It's real easy to get into ICE when the SOC is low and there's very little EV power available. It's the unnecessary ICE burns that make the difference when you're only using 2.3 ounces of fuel for a 15 mile trip, so a feature that allows access to more EV power reduces unnecessary fuel usage.

 

I've gotten to the point where I need a specific speed with non-zero SOC rolling through a dip in the road, and I can make it home on EV every time, as long as EV+ kicks in for the last coulple stops and hills. It's fun watching the tank mileage climb, knowing I've used all the fuel I need.

 

Personally, I think that's how the car should work all the time....

 

Have fun,

Frank

[stevedebi]

EV+ is a prime tool for those playing the hybrid mileage game.

 

The end of most trips, I'm driving at moderate speed through neighborhoods, with lots of turns, hills and stop signs. It's real easy to get into ICE when the SOC is low and there's very little EV power available. It's the unnecessary ICE burns that make the difference when you're only using 2.3 ounces of fuel for a 15 mile trip, so a feature that allows access to more EV power reduces unnecessary fuel usage.

 

I've gotten to the point where I need a specific speed with non-zero SOC rolling through a dip in the road, and I can make it home on EV every time, as long as EV+ kicks in for the last coulple stops and hills. It's fun watching the tank mileage climb, knowing I've used all the fuel I need.

 

Personally, I think that's how the car should work all the time....

 

Have fun,

Frank

I.E., an electric car... there is no way to recharge that HVB without using a lot of gas, so I suppose Ford did the best they could.

 

I wish my Energi had more battery as well, but I suppose there are limits as to what is practical.

[Jus-A-CMax]

I left my EV+ on for work and home. For home, I have a hill to climb so its no big deal if I sipphon out the SOC in EV+, better than burning gas to climb my hill. In the morning, I start with 1/3 SOC and go to 2/3 SOC by the time I reach the main road - thats using the hill to double charge with braking and ICE warming up.

 

Call it as you see it, theres no right or wrong since each of us have different driving conditions and terrains. 

[fbov]

...there is no way to recharge that HVB without using a lot of gas...

Per my response on the EV Miles thread, I suspect you have greatly underestimated the "charger" capacity to fill the battery (to use the original TRW terminology).

 

Have fun,

Frank

[stevedebi]

Per my response on the EV Miles thread, I suspect you have greatly underestimated the "charger" capacity to fill the battery (to use the original TRW terminology).

 

Have fun,

Frank

I'm basing my response on my real-world experience - if not carefully done, I get less MPG when I attempt to recharge the HVB from the ICE.

 

I'm not sure what you mean by the "charger" capacity. Do you mean the generator that transfers energy from buring gasoline into electric energy?

 

But really, if it were economical to use the ICE to recharge the HVB, Toyota and Ford would have done it long ago.

[fbov]

Toyota and Ford do exactly that in their hybrid models. It's the basis of TRW's power split device.
(I find TRW's "Speeder" and "Torquer" nomenclature more clearly convey the concepts than "MG1" and "MG2.")

 

In a non-plug-in car, there's only one energy source - gasoline. Every EV mile you drive is just using energy the car stored when the engine was running. This diagram shows the various options, along with an estimate of relative capacity.

 

- Turn fuel into motion and you have kinetic energy (KE).

- Slow down by driving up a hill and you convert KE into potential energy. Recover it driving downhill.

- Turn fuel into electricity by using the ICE to run the Speeder (the car can be stationary or in motion).

- Turn fuel into electricity by first converting it to motion, then using the Torquer to capture the KE by regenerative braking.

- Recover the electricity stored in the HVB by using the Torquer for propulsion instead of the ICE.

 

ALL the energy comes from fuel, unless you have a plug-in hybrid.

 

Now, of course you get poorer instantaneous mileage from the ICE when you're converting fuel into both motion and HVB charge, but charging the HVB just increases the ICE load at that RPM, improving it's efficiency (reducing it's specifc fuel consumption).

 

That's how you get more miles out of your fuel; you store the excess energy until you need it!

 

Have fun,

Frank

 

 

[stevedebi]

...

 

Now, of course you get poorer instantaneous mileage from the ICE when you're converting fuel into both motion and HVB charge, but charging the HVB just increases the ICE load at that RPM, improving it's efficiency (reducing it's specifc fuel consumption).

 

That's how you get more miles out of your fuel; you store the excess energy until you need it!

 

Have fun,

Frank

I'm not sure if you were replying to my post or not, but I appreciate the clear explanation of how the car works - I've owned hybrids for many years, but new folks can use explanation.

 

There is no free lunch, and I think I'm going to have to stand by my statement - it makes no sense to use the ICE to charge the HVB. Both Toyota and Ford choose not to do this any more than necessary, even with their plug in models that theoretically could hold more charge if they wanted to use the ICE to recharge. I know that in my Energi, Ford doesn't use any more of the HVB than the conventional C-Max on the highway; it uses a similar (fairly small) amount of the battery. I've seen .5 KWh, but never tried to measure it myself.

[chrisl]

The only scenario I can see where this would help is if you use EV+ to climb the last stretch of a very long hill—a hill that is long enough to fully recharge your battery on the way down. Then on your next drive, you spend that much less time wasting regen power because your battery is full. But this is a scenario that does not apply to most, so how does EV+ really help?

 

I live on that hill. 

 

I have to drive up to the top of a long grade and then have a shorter steep descent to get home.  Before EV+ recognized my home, the battery would be maxed out before I even hit my street, so I wasn't getting back a bunch of the energy from climbing to the peak..  Now that it knows where I live, I can run the battery down getting to the top of the hill (if I'm careful I can avoid the ICE kicking in on the steep part at the crest) and then roll into the driveway with the SOC at about 50% or a little more.

[fbov]

I was responding to you, Steve, and I'm glad to hear we agree on the overall process. It's my understanding that the Energi is a "hybrid" hybrid, in the sense that acts like a plug-in (i.e. FFE) in some cases, and like a standalone (i.e. C-Max Hybrid) in others.

 

You may be right that in an Energi, the ICE will not charge the full 7.5kWh battery capacity, but it's misleading to state:

"it makes no sense to use the ICE to charge the HVB. Both Toyota and Ford choose not to do this..."

as that statement is patently false! In the absence of a plug, all HVB charge comes from the conversion of fuel by the ICE, 100% of it. There are no other paths available.

 

You're reasoning from the specific (this is how my Energi works) to the general (this is now all Ford and Toyota hybrids work), which is a very dangerous thing to do if you want to reach accurate conclusions. TANSTAAFL* certainly applies.

 

HAve fun,

Frank

 

*There Ain't No Such Thing As A Free Lunch.

[stevedebi]

I was responding to you, Steve, and I'm glad to hear we agree on the overall process. It's my understanding that the Energi is a "hybrid" hybrid, in the sense that acts like a plug-in (i.e. FFE) in some cases, and like a standalone (i.e. C-Max Hybrid) in others.

 

You may be right that in an Energi, the ICE will not charge the full 7.5kWh battery capacity, but it's misleading to state:

"it makes no sense to use the ICE to charge the HVB. Both Toyota and Ford choose not to do this..."

as that statement is patently false! In the absence of a plug, all HVB charge comes from the conversion of fuel by the ICE, 100% of it. There are no other paths available.

 

You're reasoning from the specific (this is how my Energi works) to the general (this is now all Ford and Toyota hybrids work), which is a very dangerous thing to do if you want to reach accurate conclusions. TANSTAAFL* certainly applies.

 

HAve fun,

Frank

 

*There Ain't No Such Thing As A Free Lunch.

I love Heinlein books, but did you know he didn't invent the term TANSTAFL?

 

I probably shouldn't mention Toyotas; I try not to comment on models I have not owned. My early hybrid knowledge was from study of HSD, but after my FEH I switched to experience base.

 

I meant that Ford (at least) chooses not to utilize the full HVB in the EV Later mode. If it were efficient to use the ICE to charge the HVB, they would have utilized the entire capacity of the HVB on the highway. Instead, they chose to reserve a small portion of the HVB, and only go past that if there is a long downhill and they exceed the "sustaining" capacity level. But then (unless you capture the energy by cycling away from EV Later and back), it simply uses up that excess energy until it gets back to the maximum "sustaining" level.

 

Of course they use the ICE to charge the sustaining portion - that is how the hybrid works. But there has to be a reason that they chose not to use the entire HVB. I've seen other folks claim that the ICE is more efficient at highways speeds, with lots of supporting information.

Edited December 10, 2014 by stevedebi

[plus 3 golfer]

I love Heinlein books, but did you know he didn't invent the term TANSTAFL?

 

I probably shouldn't mention Toyotas; I try not to comment on models I have not owned. My early hybrid knowledge was from study of HSD, but after my FEH I switched to experience base.

 

I meant that Ford (at least) chooses not to utilize the full HVB in the EV Later mode. If it were efficient to use the ICE to charge the HVB, they would have utilized the entire capacity of the HVB on the highway. Instead, they chose to reserve a small portion of the HVB, and only go past that if there is a long downhill and they exceed the "sustaining" capacity level. But then (unless you capture the energy by cycling away from EV Later and back), it simply uses up that excess energy until it gets back to the maximum "sustaining" level.

 

Of course they use the ICE to charge the sustaining portion - that is how the hybrid works. But there has to be a reason that they chose not to use the entire HVB. I've seen other folks claim that the ICE is more efficient at highways speeds, with lots of supporting information. 

I don't think it's about ICE inefficiency in charging the HBV in EV later mode or in the Hybrid.  The  PCM can't predict future driving conditions (yet) and thus optimize use of ICE.  Give the PCM the route via GPS and the next charging destination and Ford might be able to develop an algorithm to better use ICE in charging the Hybrid or Energi.  But currently, there needs to be predefined rules to apply to typical conditions.  Otherwise, drivers would complain about the PCM charging the HVB full with ICE on the highway and they are only 5 mile from home or a charging station and can charge cheaper with electricity.  Drivers (hyper-milers) can and do choose  to alter vehicle load trying to optimize use of ICE and EV but the driver can only do so much.  Maybe we need a bank of switches to tell the PCM how we want to run ICE. :)

 

Of course one does not want to cycle the "big" HBV routinely with ICE to full capacity as this will affect the useful life of the HBV.  Battery degradation will accelerate with number of cycles and charging past a certain % SOC. Does anyone know what SOC the Energi HVB is charged to when full?  It's capacity is 7.6 kWh but what's the max. capacity it is charged to?