[Cam-WA]

Really good advice here!

I have a follow-up question about Hybrid mode. If I understand correctly, the advice is to AVOID hybrid mode. That is, if I notice I'm in hybrid mode, accelerate so that I'm in ICE-only mode (assuming conditions are appropriate) to get the maximum charge to the HVB, and then let off the accelerator when I'm in a place where doing that would allow me to maintain speed in EV only mode.

The use-case I can think of is when going up a not-too-steep hill. So, instead of trying to stay in hybrid mode to allow the car to use less ICE, the suggestion is to go up the hill in ICE-only mode and then once I've crested the hill, go into EV mode.

Do I understand this correctly?

As a second question, the advice here is to use EV Coach when one is new to the vehicle. Why not just keep an eye on the right hand part of the dash display which shows the KwH used by the ICE or being supplied by the HVB rather than the bar in EV Coach. I can use the right hand gauge to see whether I'm in EV-only, hybrid, or ICE-only mode, AND if I'm in EV-only mode, I can see how much I'm using (I, too, have noticed that I can drive for a long time in EV-only at 1-2KwH on level ground)

 

[Cam-WA]

There is no ICE-only "mode", per se, just EV (ICE off) and Hybrid (ICE on). In Hybrid mode, reducing throttle will bring EV power to 0, so you are not depleting the HVB. This is your ICE-only "mode."


Exactly right. I put the attached together for C-Max, but the Escape is very similar.

Burn fuel (chemical energy) at high efficiency. The car will apportion the resulting energy to accelerate the car (kinetic energy) or charge the HVB (electrical energy). As ICE runs to move the car, store energy in both the HVB and in altitude (potential energy). Then tap those stores to maintain speed in EV mode, with ICE off. Use as little HVB charge as possible by taking advantage of downslopes as you suggest. Charge gently uphill, EV down, then repeat on the next hill. You'll discover tiny hills you never noticed, but which change the car's speed. Learning those is grad school.
View attachment 77199


Because you need a "fuel gauge" for the EV side. EV Coach shows the ICE-on threshold as an outline around the EV bar. The length of the outline is determined by HVB SOC. As you EV, the threshold starts to drop; the outline shrinks. That feedback allows you to adjust throttle to reduce EV demand before ICE comes on, as driving conditions require.


Indeed. And EV coach tells you when to back off to that level.

Absent hills, or in addition to them, I use speed. Gently speed up using ICE, then EV using a little less throttle than required to maintain speed. Repeat. This is classic "pulse and glide" hypermiling technique and the car loves it.

I also find I get a lot more charging at 10kW ICE power up to about 20kW, while 30kW quickly gets into hybrid mode as SOC increases. That means a longer, gentler ICE run increases HVB SOC. That's very useful just before a long downhill.

TLAs - three letter acronyms.
HVB - high voltage battery. SOC - state of charge. ICE - internal combustion engine.
And MJ - megajoule, from the chart, is an alternate unit of energy, equal to 0.27 kWh... not sure why I didn't use kWh!

Stay well,
Frank

Thanks for the detailed response, which I think I understand most of. Until I actually see and use the EV Coach, I don't think I fully get how it's going to work, but your explanation provides a good starting point.

One thing I'd like to clarify is this: Gently speed up using ICE, then EV using a little less throttle than required to maintain speed. The net effect of this is that one will not be maintaining a steady speed (let's assume that conditions allow for this and that one is on level ground), because using less throttle than is required to maintain speed will result in slowing down (hence the term "pulse & glide"...). Why is this more efficient than gently speeding up using ICE and then maintaining speed with EV until the SOC is low enough that the ICE kicks back on? I read some articles about hypermiling, and what I read is that the goal is to keep the ICE off as much as possible, which makes sense, since the instantaneous mpg is effectively infinite when the ICE is off. But the articles I found didn't address the question of why it is more efficient to try to minimize the drain on the HVB through the pulse & glide technique vs using the HVB to maintain speed until either road conditions or depleted SOC require the ICE to come back on.

Secondly, more for curiosity than anything else, how did you determine that one gets more charging between 10-20kW ICE power?

Thanks again for the time you took to answer my questions...I've driven a Gen 2 Prius for many years, but I think I was sufficiently impressed with the mileage I was getting in comparison to anything else I had driven or anyone else around me was getting to really think about how I might improve mileage even more. I can't expect the Escape to match a smaller and lighter car, of course, but I might as well see if I can learn to do better (without driving my wife bananas when she's riding shotgun...)

 

[Cam-WA]

Did you watch my How to drive a CMAX to get good gas mileage video? It answers all your questions like FORD's program is designed use extra power where the ICE is more efficient and use the excess energy to charge the HVB.

Paul

Yeah, I just did. Quite well done.

In your video, you suggest accelerating from a stop using EV, until reaching about 15mph, followed by ICE acceleration at "2 bars." The Escape doesn't have those bars, so if I combine what you said and what @fbov said, perhaps the functional equivalent of "2 bars" is "between 10kW and 20kW"?

And , if I understood @fbov correctly, his suggestion is to accelerate from a stop using ICE, to maximize HVB SOC for later use.

I suppose that I could take a route I go on frequently and some times drive it with accelerating from a stop using EV and other times accelerating from a stop using ICE, but variable traffic conditions may make such a test inconclusive at best.

 

[Cam-WA]

Thanks for the detailed response; followup questions below...

get rolling on EV, then use ICE to come up to speed. We called it "chasing blue." At rest, the EV available outline is small. As you speed up, the outline grows. The "game" is to press the throttle gently enough that the solid bar (throttle) remains inside the expanding outline (available). C-Max was hard to get past 10 mph, Escape gets to 20 mph easily before cutting over to hybrid.

The reason is in the kinetic energy equation, KE=1/2mv^2. Getting to 20 mph uses 1/4 of the energy needed to hit 40 mph, the kind of EV/ICE energy ratio you want. It's a chance to use a small amount of EV, followed by ICE charging. It's a small thing, but a real benefit accrues due to frequent use, literally every time you stop. Well... not every time. You do need a healthy SOC; don't expect it if you've run the battery down.

So, are you suggesting that one should gently accelerate on EV until the ICE kicks in on its own, or to force the ICE to kick in at some point after starting with EV by giving it more throttle?

In C-Max, "2 bars" was the ICE-only threshold. Greater acceleration brought on Hybrid mode unless the HVB was empty. I'd say it's more like 30-35 kW in Escape.

Hmmm...I don't recall ever seeing 30-35 kW in EV mode, or am I misunderstanding something here?

The initial "how-to" for C-Max said to accelerate at 2 bars so you'd get up to speed and turn ICE off sooner, while still charging. I found I was running out of EV too soon. I started using more like 1.5 bars. It took longer to come up to speed, but I ran at lower RPM so a lower fuel usage rate. I had a 15 mile, 30 mph commute that provided a place to test. I found the added fuel used in the longer, lower ICE burn bought a much higher %EV and significantly higher mileage.

So, once again, that suggests a gentle start in EV followed by gentle continued acceleration via ICE, while staying out of hybrid mode.

Does terrain matter much in the general approach of "start in EV then switch to ICE, that is, starting from rest on an upward slope vs flat vs downward slope?

Thanks again...I really appreciate the time you're taking; I'm learning a lot.

 

[Cam-WA]

You're getting wrapped up in the details; drive a little and see what works for you.
Frank

Right you are!

 

[Cam-WA]

So, I've spent some time driving with EV Coach, and here are my observations thus far...

1. As has been pointed out by others, having the blue rectangle show the SOC is a real help. When I'm getting close to running out of (electric) steam, I've been able to back off the throttle a bit and keep in EV mode a little longer, or, depending on terrain and driving circumstances, I can make a deliberate decision to kick the ICE on (gently...) to gain charge before the next EV session.
2. I have been (pleasantly) surprised how little time it takes running the ICE to get a reasonable amount of charge. This is a real change from my Gen 2 Prius, where it takes a lot long for the HVB to charge using the ICE. (It also took a lot longer on the Prius for the SOC meter to empty out. I'm wondering if what is happening here is that on the Prius, perhaps the meter is showing 0-100%, even though the car tries really hard not to get to either extreme, while maybe on the Escape the SOC rectangle is showing, let's say, "usable SOC" and not bothering to show us SOC that we can't actually use.)
3. One thing that is a bit frustrating is that when stopped, the blue SOC rectangle seems to be always very small (right hand edge under the E). Then, when I start up from the stop, the rectangle often grows rapidly to whatever the SOC actually is, even though I'm in EV mode and therefore am not charging the HVB from the ICE. If I knew while I was stopped what the SOC was, I might make different decisions about how I accelerate. For example, if my SOC were pretty good and I was on level ground, I'd probably accelerate and stay in EV mode, but if the SOC were low, I'd kick the ICE on to get charge.
4. There seem to be times when I can't avoid being in hybrid mode (EV + ICE). I haven't pinned that down precisely yet, but my impression is that this seems to occur when SOC is high and I'm heading uphill. In order to get the EV gauge to 0, I have to really accelerate fairly sharply. I'm not sure that's a good idea, since I'm above 30kW ICE. Is it better just to stay in hybrid mode and accelerate more gently, as would be my typical pattern?
5. This is only an impression, but my sense is that with Auto Hold ON, if SOC is somewhat low (and particularly if I'm headed uphill from the stop), the slight extra accelerator pressure need to tick Auto Hold off can start the ICE, whereas with Auto Hold OFF, just taking one's foot off the break gives the opportunity to accelerate in EV mode. (This isn't typically useful with a lower SOC, but today I was in a situation where the light turned green but I could see that I only had a short distance I could travel before I'd have to stop again, so staying in EV mode would be both possible and useful).
6. Based on my testing today in familiar territory, I'd say that the EV Coach is improving my MPG.

 

[Cam-WA]

1. You're riding an electric motor torque curve, which are all flat at low RPM due to current limitations. Once you start moving, the EV Available bar inflates as current demands fall. I try to use the same gentle throttle application, regardless SOC.
   Sometimes I succeed.
   View attachment 77260

So, if I understand you correctly, what you are saying is that because the torque requirements are high when starting from a standstill, the EV-Available rectangle is going to be very small because regardless of the SOC, the HVB can't sustain that level of torque very long. BUT, because as soon as I start up the torque requirements go down, as I accelerate in EV mode the torque requirements drop and the EV-Available rectangle grows.

Yes?

If that's correct, a remaining question is, Why does the energy used gauge on the right side of the dash display show low electric energy use when starting gently from a standstill? I would have thought (perhaps incorrectly) that if there is a high energy use at startup to get the car rolling, I'd see the energy used gauge reflect that via an immediate high kW number followed by a decrease. Perhaps the time of high energy used is so small that the engineers didn't want that to show on the gauge?
[/QUOTE]

 

[Cam-WA]

Are you familiar with the Weber State videos? He disassembles hybrid drivetrains, electronics and battery systems, including all the Prii and Ford generations. Talk about differing engineering approaches....

Nope, never heard of them. Now I have got some fun stuff to look at and dig my brain into while I'm mostly stuck at home.... Thanks.