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Discussion Starter · #1 ·
Hi all - new to the forum and UK owner of an SR model hybrid.

I've had the car around 9 months and not driven much because of lockdowns, etc. But I'm confused about the car's choice of when to go into EV mode. Coming off a steep hill, the battery can be full, but the car still doesn't select EV mode when back on the flat, which I thought it would do immediately because the battery was charged. And it seems to slip into EV less often then I imagined it would, generally. Just wondered if this was normal or a potential fault.

Finally, I have tried once to select EV manually whilst driving (20-30mph) in that situation, but it wouldn't engage. Does it stop manual selection for certain reasons?

Thanks all.
 

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Triangular Horse Knees
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Hi and welcome.

Best response to your query will come from @Charlie1960 or @CRV4575.

In the meantime, I would check the owners manual which sets out the conditions for how and when EV mode kicks in.
 

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2020 CR-V Hybrid EX-L
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Yes, if you push the button twice it will generally tell you. I’ve had it say ‘cabin heating’ and ‘hard acceleration’, as well as battery too low.

The system is pretty smart, and it seems to use the electric motor to boost performance rather than just go into EV mode.

One of the status screens shows the battery and you can see when it charges and when it’s running solely on battery and when it’s mixed.

I see the ‘best’ mpg during stop and go traffic, where I get upwards of 40mpg over 10 miles - with the system managing the EV just fine.
 

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Triangular Horse Knees
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And it seems to slip into EV less often then I imagined it would
Also bear in mind that the CR-V Hybrid is NOT a full EV car. In EV mode, its range is probably no more than a mile before the engine kicks back in. From what you describe, there is 100% no fault with what your car is doing :)
 

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2019 CR-V Hybrid SR Crystal Red Metallic
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Also bear in mind that the CR-V Hybrid is NOT a full EV car. In EV mode, its range is probably no more than a mile before the engine kicks back in. From what you describe, there is 100% no fault with what your car is doing :)
I have to agree. The car knows what it’s doing and it would be difficult to fully anticipate when EV will be used. It comes and goes. If the cars fuel economy is holding up and the powers there when you need it then I would say it’s working fine.
 

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When I tried the Honda I was so impressed by the hybrid system and the brakes which at the time where so good compaired to the toyota
I have had mine for 14 months now and I am pleased with the MPG so I just let the car do its own thing
You are right it is not often in full electric mode but the way the system works I do not think it matters
 

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When I tried the Honda I was so impressed by the hybrid system and the brakes which at the time where so good compaired to the toyota
I have had mine for 14 months now and I am pleased with the MPG so I just let the car do its own thing
You are right it is not often in full electric mode but the way the system works I do not think it matters
I totally agree Honda has the regen brake "feel" figured out, unlike other hybrids I have driven.
I have found that the car's selection of EV mode is very repeatable. I make the same drive most mornings and EV mode engages within 10 feet of the same place each time.
Like many I initially paid close attention to where the energy was coming from and going to, but finally figured out the car is quite capable of managing energy without my supervision.
The battery's main purpose is as a place to store energy recovered by the regen braking, not as a way to drive the car.
 

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The battery's main purpose is as a place to store energy recovered by the regen braking, not as a way to drive the car.
This is a misconception that really gets in the way of understanding this car. It's just simpler to explain than the real reason, so it is almost all Toyota said about their cars when they jumped into the early lead in HEV sales. (In my opinion, this is because Toyota expects their owners to be less capable of understanding the real reasons than Honda.)

Here's one result of a study I saw in the World Electric Vehicle Journal, titled "Fuel Economy of Plug-In Hybrid Electric and Hybrid Electric Vehicles: Effects of Vehicle Weight, Hybridization Ratio and Ambient Temperature."
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What it measures is the amount of energy that reaches the battery, as a fraction of the change in the kinetic energy of the car. The two tests were a rapid braking from 60 mph to a full stop "which includes skid stops with ABS in operation if the vehicle is so equipped," and a "coast down braking relying on the rolling and regenerative braking resistance of the vehicle" to only 10 mph. Note that:
  • HEVs typically stop using regen between about 7 and 10 mph.
  • The 2015 Honda Accord Hybrid had the same basic design as the CR-V hybrid, but earlier versions of both the engine and the motor. And, it was a plug-in hybrid, whose larger battery allowed it to accept charge at a faster rate. I don't know how this influenced the result of the 60-10 mph test, but our cars would not do as well at the 60-0 mph one.
  • There will be additional losses when converting that charge back to kinetic energy.
The additional loss, and the fact that they didn't go to a full stop in the second test, is why I usually say HEVs can only recoup, at best, 1/3 of the energy that is normally lost to braking. The point today is that this is not a significant source of charge in the battery.

Here's a blowup of another plot that I'll explain in just a bit.
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The heavy black line is the State of Charge in a first-generation Prius. The car had a surplus of charge when it braked to a stop from ~33 mph; the red lines show how much the SoC went up. Then it accelerated back to ~28 mph, and used about twice that charge in the process.

Here is the full plot. The Prius drivetrain was being put through the EPA's Urban Dynamometer Driving Schedule (UDDS) with different initial States of Charge, to see how that affects EPA city mileage estimates. The data came from a National Renewable Energy Laboratory paper titled "Battery Usage and Thermal Performance of the Toyota Prius and Honda Insight for Various Chassis Dynamometer Test Procedures." I added the colored lines.
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What I find interesting in this, is that regen braking had to be the same in each, but the trends in each were to use the engine to drive SoC to between about 54% and 57%.

And this last one emphasizes what the battery is really for.
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It is from a Honda submission to the same World Electric Vehicle Journal, titled "Efficiency Enhancement of a New Two-Motor Hybrid System." Yes, the system in the Accord and CR-V.

BSFC is "Brake Specific Fuel Consumption," which is basically how much fuel our engine uses when pushing against a brake providing the torque indicated.
  • The Yellow Dots are where the engine would run, in engine drive (clutch on), without the battery.
    • The car's speed (horizontal axis) determines the engine speed.
    • The lower set of yellow dots represents cruising situations.
    • The higher set represents acceleration.
  • The blue dots are where it would run, in hybrid drive (clutch off), without the battery.
    • The power needed (gray parametric curves) determines the engine's speed.
    • RPMs would be varied along a parametric curve to place the engine speed on the blue "Hybrid Operating Line", where efficiency is maximized.
    • The left set of blue dots represents cruising situations.
    • The right set represents acceleration.
THE POINT OF THE BATTERY IS TO ALLOW THE ENGINE TO MOVE FROM THE YELLOW OR BLUE DOTS, TO THE PURPLE DOTS. The purpose of the traction motor is to act as a generator for Engine Drive "charge", or as the motor for either "assist." Regen Braking is, essentially, a variation of "Engine Drive Charge" with the clutch open, but with the wheels spinning the traction motor as a generator. Its contribution to charge is small compared to what this figure indicates, unless you coast down a lot of hills.
 

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Hi all - new to the forum and UK owner of an SR model hybrid.
Welcome, and sorry about inserting that last technical bit. But since my hybrid is an Accord, even though it has the exact same components up to the AWD system, it will behave somewhat differently. So I try to limit myself to what is common between them. The following assumes the CR-V works the same as the Accord:

I'm confused about the car's choice of when to go into EV mode. Coming off a steep hill, the battery can be full, but the car still doesn't select EV mode when back on the flat, which I thought it would do immediately because the battery was charged. And it seems to slip into EV less often then I imagined it would, generally. Just wondered if this was normal or a potential fault.
There are three things you left out of this: did the battery fill completely, what mode (ECO/NORMAL/SPORT) do you drive in, and was it so long a hill that the engine cooled down from operating temperature?
  • If the battery is completely full, you should know it. Either regen braking will stop working (if you haven't used the deceleration paddles), or it will continue to work (if you have) but instead of charging the battery it will use the generator to spin the engine as a form of engine braking.
  • The mode you are in determines the range of battery charge that the car tries to maintain. It normally will try to keep the battery within about a quarter of its total possible range, but where that is depends on the mode.
    • Below that range you can't use EV.
    • Above that range the car will go into EV by itself, if it can.
    • In that range things aren't certain.
  • I can't say for sure what the range is in the CR-V, but in the Accord:
    • ECO mode has a target range that is about 25% to 50% charged. This way there is a lot of room for regen.
    • NORMAL seems to be about 35% to 60%.
    • SPORT is about 50% to 75%, but can go higher. That way there is a lot of power for acceleration.
  • It is confusing, but "EV Drive" is what you mean in your question. That's when the engine is off. It lights up the green "EV" icon in the display.
    • EV Mode means you pushed the button, and want the car to use EV Drive if it can. It lights up the green car silhouette, with the black "EV" inside it.
    • When you push the button, the car should tell you if some condition means it can't currently use EV Drive. It will not go into EV mode in this case.
    • About the only time you can be in EV Mode, but not EV Drive, is if you are pressing the gas pedal so hard that EV Drive is not enough power. It won't tell you, but it will stay in EV Mode until it becomes possible to use EV Drive.

Finally, I have tried once to select EV manually whilst driving (20-30mph) in that situation, but it wouldn't engage. Does it stop manual selection for certain reasons?
Like I said, it should:
  • Tell you what condition prevents EV Drive (engine too cold, charge too low, etc.), and not shift into EV Mode (no green car silhouette), or...
  • Shift into EV Mode but not EV Drive (silhouette but no green "EV") if you are trying to accelerate.
 

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Jeffjo, great writeup.

When driving on the highway, if you use the cruise control, the CRV Hybrid will not go into EV mode as often as if you drove with your foot. The cruise control will try to keep the CRV going at some rate that will tell the computer that it is under hard acceleration. You can see this if you use cruise and going down a hill, if the CRV does not go into EV, switch off cruise and >90% of the time it will go into EV and will still be going as fast. This is especially true if you set you cruise >70 mph
 

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Great answers but sometimes to much information is not good for you
 

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If you want to see something, drive an NSX... that hybrid system looks interesting!
 

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Discussion Starter · #14 ·
Thanks so much everyone for the replies and the warm welcome. To answer some questions...

There are three things you left out of this: did the battery fill completely, what mode (ECO/NORMAL/SPORT) do you drive in, and was it so long a hill that the engine cooled down from operating temperature?
I have been driving in ECO mode most of the time since I bought it, and was doing that coming off the hill. The hill was long enough for it to show a fully charged battery by the bottom of it. I just assumed that, with a full battery on the flat and no outrageous acceleration, it would automatically go into EV Drive (with the green letters showing) for as long as it could, but it didn't.

I'm going to have to try this again and look at the different silhouettes you describe, as well as the green EV icon, I think. I will play around with EV Mode a bit.

Thinking about it more, I'm confused as to why it has EV Mode as an option at all... Shouldn't the car be prioritising that as much as possible anyway? I'm wondering what the pros and cons are of being able to force it.

Thanks again everyone
 

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Thinking about it more, I'm confused as to why it has EV Mode as an option at all...
Because it is easy to think that it doesn't involve burning gas (petrol), and that you are getting something for nothing. Both are wrong - you just burned the gas at an earlier time. But people want to believe it, so many do.

As I understand it, early hybrids in North America didn't have one. It was first included in a Toyota Prius in Europe sometime around 2009. North America versions didn't have it, but they did have the software to use it. Somebody discovered it, and aftermarket vendors started making them. So Toyota started including it in all markets, calling it a "feature." Others followed, since they had to compete.

Shouldn't the car be prioritising that as much as possible anyway?
It really isn't more efficient. In fact, it is less efficient. But it uses energy that was generated more efficiently, as I explained above. What I'm saying is that the benefit happens when you put energy in under the right conditions. There are losses whenever you take it out, and the benefit exceeds the losses only if you let the car do it.

A simple analogy might help. Remember the days when money only came in the form of currency? Some people would, at the end of every day, empty the change in their pockets into a jar. When the jar was full, they would take the money and use it for a treat, like dinner at a fancy restaurant. But that meal wasn't "free," you paid for it bit by bit over the previous weeks. That's what EV Drive does.

Now, image it is a magic jar. For every dollar you put in, a quarter magically appears. But for every dollar take out, a dime disappears. This is how a Hybrid puts charge into the battery. Most of the time it is more efficient to generate more power than the car needs, and save the extra in the battery. But there are additional losses when you take power out. But the gains exceed the losses.

The difference, is that the car needs to use power from the battery for more than just EV mode. It has to make sure there is enough most of the time. That would be like if you need to keep a minimum amount in the jar for emergencies.

Now, pushing the EV Mode button is equivalent to emptying the jar, completely, as soon as there is enough for a quick meal at McDonald's. Not only do you not get a fancy meal, but now you need to fill the jar up to the emergency-reserve level. And you don't get the free quarter when you rush it.
 

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Discussion Starter · #16 ·
Thank you @JeffJo - that's a very helpful analogy. And thanks again for putting in so much time to answer my question. :)

I suppose I'm still confused as to why, when the battery was full from the hill descent, it still didn't just stay in EV Drive until it had drained the battery back to the optimum level, but I'm much clearer now in general. I'd been choosing maximum regen braking with the paddles coming downhill to try and get maximum efficiency, but it sounds like I needn't bother with that.
 
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