Econ + HV mode

[KentuckyKen]

The above answers are really good but don't worry if it doesn't all make sense now, be sure to bookmark their comments and read them again later after you get more familiar with the systems.

If you are looking for the simplest explanation either for yourself or for your wife, it would be the commonly heard admonition "Just drive it!" In other words the only buttons that you really need to push are Power, D and R (well I guess you don't really push R, you lift it). You don't really need to know or think about modes, the car will handle all of that for you. You will get great mpg, especially if you charge up before you drive off, but even if you don't charge up you will still get very respectable mph for a car this size.

Okay but likely at some point curiosity will get the best of you and you will want to at least know what mode the car is running in at a particular moment, and why it acts and sounds differently at times. And you might wonder if you might benefit from experimenting with the different modes.

So the first thing to know is that if you "just drive it" you will start out in Normal mode which is the default. And you will start out in EV mode. As pointed out by KentuckyKen there is no indicator for these modes, unlike Econ, Sport and HV which all have indicators when they are turned on. Now there is an "EV" indication above the speedometer but that does not indicate EV mode, as far as I know it's main purpose is just to create confusion.

As I mentioned when you start out you will automatically be in EV mode, assuming the battery has at least some charge. It will remain in EV mode as long as you have EV miles remaining. EV range is indicated by bars on the left side of the screen, as well as numerically indicated on the screen depending on what is being displayed on the screen at that moment. When EV range reaches 0 it will automatically switch to HV mode. Now to add a little more confusion, when that happens it does not indicate HV mode on the screen. It only indicates HV mode on the screen when you push the HV button. Which you are not doing right now because remember you are "just driving it".

While you are driving, sometimes you will be driving only electric, sometimes gas, sometimes both. That's not for you to worry about, or even notice if you don't want to, it knows what it is doing. But if your curiosity gets the best of you and you do glance at the EV range, you will notice that in general whenever the EV range is above 0 the car will normally drive very quiet. After EV range reaches 0 and it switches to HV mode the gas engine will operate, but oddly you won't always hear it. For one thing the Clarity is well insulated, but also even when EV range is 0 the car will still be using battery power much of the time. How can that be? Because EV range 0 doesn't mean the battery is empty, it just means that you will no longer be driving all electric, it will be a combination of gas and electric, just like a normal hybrid. That's why it is called HV mode because it is operating like a standard hybrid.

Sometimes even when your EV range is greater than 0 the gas engine (aka ICE) may come on briefly. This is normal. There are whole threads about this with lots of consternation and hair pulling, but all you need to know is that it is normal and you aren't doing anything wrong.

Also in some specific situations, usually related to climbing a grade or incline, the gas engine may become very loud, even alarmingly loud. Believe it or not this is normal also, but it shouldn't happen very often, just know that it is no cause for alarm. Your car is not being harmed, it is just being efficient in a very noisy way. And yes there are hair-pulling threads about this topic also.

Okay at some point after you gain some experience and also start noticing more what the car is doing, you may (optionally) decide to take at least some manual control over what is going on. To keep it simple and less confusing probably the best one to start off with is the HV button, and use it for one simple purpose, to delay using up the EV range. After driving for awhile you will probably notice that on surface streets the gas engine is more noticeable when it is running, but on the highway you hardly notice it. This is because at highway speeds you have a lot of road and wind noise drowning it out, and also when it gets into its "gear mode" driving steady over about 45 mph the gas engine gets even quieter. You don't have to think about trying to get into gear mode, or really even know about it, it's all automatic. KentuckyKen just mentioned it as part of his explanation about how the car works.

The main point is that most people would prefer if possible to use the gas engine on the highway instead of on surface streets. Of course if your entire trip will be within your EV range it won't matter, just drive EV the whole time. But let's say you are going on a trip that is 100 miles round trip. Even with a full charge you will be driving HV about half of the time. If you do nothing it will use up the EV range first, and once you get on the highway at say 70 mph the EV range will get used up pretty quickly, then you will be HV for the remainder of your trip until you arrive home. But if you prefer to not use up all of the EV range at the beginning of the trip but save some of it for later when you will be driving on surface streets, well that's what HV mode is there for. When you get on the highway, press the HV button, in this case since the button was pushed you will see the HV indicator on the screen. After pushing the HV button you will notice that EV range will continue to decrease briefly, then stabilize and remain pretty much the same as long as you stay in HV mode. When you later are on a surface street and want to switch to EV mode, simply push the HV button to turn it off. Or if you stop somewhere and turn the car off, the next time you start the car it will automatically be in EV mode, you don't have to press anything.

The bottom line, if you try HV mode and think "I like this, I enjoy controlling when the gas engine comes on" then HV is something you will want to use. However if you think "Do I really have to worry about this?", no you don't, if you don't see a benefit in using HV mode then don't use it. Or maybe you want to use it but your wife doesn't, or vice versa. It's all good.

The other two modes, Eco and Sport, you may never need. Sport as the name implies gives a more lively feel to the accelerator pedal, and more control over paddle braking. Eco mode doesn't change the driving feel that much, but it does use the heat and air conditioning systems more conservatively to save power. Eco mode in one sense is for people who are coming from previous hybrids and enjoy maximizing their mpg, even small improvements are a challenging goal to them. However you have to press the Eco button each time you start out, otherwise it defaults to Normal. If you feel that is too much trouble, then just drive it.

What he said!!!
What a great job of making the technical readily understandable and easily usable. That post should be a sticky (if we only had them). Honda should use that as a basis for a quick start guide in the glove box for every new owner.
Well played sir, well played.

 

[Clarity Dave]

Well explained, Ken et al!

Based on this thread, I'm more convinced that one of Honda's poorer user interface choices on the Clarity was the EV indicator on the instrument panel. All it really means is "the gas engine is not running." So, I guess you could say that "EV" means "I'm pretending to be an electric vehicle right now instead of a plug-in hybrid" but I personally would have preferred an opposite indicator -- one that turned on when the gas engine started and turned off when it stopped.

The use of "EV" gives the false impression that the car can be put into an "EV mode" when in actuality it can start the gas engine at any time -- only the circumstances under which it decides to do so are altered by which buttons have been pressed, accelerator position, battery state of charge (SOC), time since the engine last ran, and so on.

For that matter, "HV" isn't that great a choice either -- not just because it's positioned as if it were an alternative to ECON and SPORT. "HV" really means "maintain the battery's SOC, more or less, if it's more than indicated zero." Once the indicated SOC is at zero, "HV" is indistinguishable from not "HV." I'm not sure what the best choice would have been, but "charge hold," say, would be clearer.

Yes, it's little wonder that many new Clarity owners are profoundly confused by all of this.

 

[Clarity_Newbie]

Well explained, Ken et al!

Based on this thread, I'm more convinced that one of Honda's poorer user interface choices on the Clarity was the EV indicator on the instrument panel. All it really means is "the gas engine is not running." So, I guess you could say that "EV" means "I'm pretending to be an electric vehicle right now instead of a plug-in hybrid" but I personally would have preferred an opposite indicator -- one that turned on when the gas engine started and turned off when it stopped.

The use of "EV" gives the false impression that the car can be put into an "EV mode" when in actuality it can start the gas engine at any time -- only the circumstances under which it decides to do so are altered by which buttons have been pressed, accelerator position, battery state of charge (SOC), time since the engine last ran, and so on.

For that matter, "HV" isn't that great a choice either -- not just because it's positioned as if it were an alternative to ECON and SPORT. "HV" really means "maintain the battery's SOC, more or less, if it's more than indicated zero." Once the indicated SOC is at zero, "HV" is indistinguishable from not "HV." I'm not sure what the best choice would have been, but "charge hold," say, would be clearer.

Yes, it's little wonder that many new Clarity owners are profoundly confused by all of this.

Clarity Dave

Unless I miss-understood your post...the energy flow screen on the infotainment center stack OR the energy flow available through the dashboard...either will illuminate the engine icon when the ICE is activated.

Granted there is no readily available notification other than the two mentioned above OR the EV light going off when in ICE activates...but still.

Hope this helps

 

[insightman]

@insightman has done the best job of explaining them, but I can’t find his post. Hopefully he will read this and repost his most cogent explanation here.

@KentuckyKen did a great job, but you can read my post here.

 

[Tek_Freek]

I'm printing all this out and putting a copy by my chair and one in the glove box. Which should have a lock.

Thanks everyone.

 

[rodeknyt]

However you have to press the Eco button each time you start out, otherwise it defaults to Normal. If you feel that is too much trouble, then just drive it.

No. Eco is the only button-controlled "mode" that persists across restarts. Once you press the Eco button, it will stay in that mode until you press the button again. You don't have to press it each time you start the car.

 

[2002]

No. Eco is the only button-controlled "mode" that persists across restarts. Once you press the Eco button, it will stay in that mode until you press the button again. You don't have to press it each time you start the car.

Thanks!

 

[MPower]

However you have to press the Eco button each time you start out, otherwise it defaults to Normal.

No, you don't have to press the ECO button each time you start out. The car will stay in ECO until you toggle it off or press Sport. I pressed the ECO button the day I got my car in October and it has been in ECO ever since.

Normal is the lack of ECO or Sport buttons pressed.

The button you have to press each time you start is HV. If you are on a long road trip, you will want to remember to press it every time you start up after a break to maintain a good SOC which seems to make driving pleasanter.

 

[RickSE]

The only real use I have found for sport mode is when I am using the ACC. At highway speeds when the car slows below the set speed it takes too long to get back up to the set speed once there is more space between me and the car I’m following. It also feels a little more sluggish going up hill. For non ACC driving all sport does is cause me to accidentally turn on my ICE when I’m on the highway.

On hot days when I’m stopping at a lot of lights in city driving it feels like the A/C keeps the car cooler when I’m not in Econ.

 

[Clarity Dave]

Clarity Dave

Unless I miss-understood your post...the energy flow screen on the infotainment center stack OR the energy flow available through the dashboard...either will illuminate the engine icon when the ICE is activated.

Granted there is no readily available notification other than the two mentioned above OR the EV light going off when in ICE activates...but still.

Hope this helps

Indeed it does. I'm quite familiar with the interfaces and have no trouble personally knowing when the ICE is running.

My point is that for the inexperienced owner, the EV symbol is confusing. Having an EV symbol indicate when the motor is not running is poor user interface design.

 

[2002]

Eco is the only button-controlled "mode" that persists across restarts. Once you press the Eco button, it will stay in that mode until you press the button again. You don't have to press it each time you start the car.

you don't have to press the ECO button each time you start out. The car will stay in ECO until you toggle it off or press Sport.

Okay you caught me, now you know how often I drive in Eco mode

I drive in normal mode and it is extremely rare that I press hard enough on the accelerator to activate ICE. I can count on one hand the times that I am aware of it happening, although it may have happened at other times that I wasn't aware.

 

[CyberDyneSystems]

... From the Owners Manual, page 11:
You may also choose to use the propulsion sources as follows:
● EV - While driving in city traffic or at slow speed.....

My apologies in advance for asking what may be a silly question, but first day Clarity owner (coming from a Prime)
How does one "choose" EV mode? I haven't seen or read mention of that button either.

 

[CyberDyneSystems]

Indeed it does. I'm quite familiar with the interfaces and have no trouble personally knowing when the ICE is running.

My point is that for the inexperienced owner, the EV symbol is confusing. Having an EV symbol indicate when the motor is not running is poor user interface design.

Looks like I may have just inadvertently become your "case in point" with my question above

 

[RobinBrain]

On hot days when I’m stopping at a lot of lights in city driving it feels like the A/C keeps the car cooler when I’m not in Econ.

From what I understand Econ mode will reduce the power of the Cooling/Heating in order to save energy. So you feeling is correct.

 

[KentuckyKen]

My apologies in advance for asking what may be a silly question, but first day Clarity owner (coming from a Prime)
How does one "choose" EV mode? I haven't seen or read mention of that button either.

Not silly at all.
You can’t choose EV. You only get to choose NOT to be in HV or HV Charge. Then by default you get the EV Ready to illuminate which is also “chosen” for you at each restart by default.

This is analogous to how you get NORMAL by choosing not to be in SPORT or ECON. Well, at least ECON gets a button and a green leaf indicator. Poor NORMAL gets nothing other than a brief mention in the manual.

Which is why this Gaijin say Honda not playing with full deck on all this.

 

[2002]

I actually think the terms EV Mode and HV Mode are correct as used on the Clarity, because each mode represents behavior similar to, but not exactly like a different category of vehicle. And it is consistent with how other hybrids use these terms. The same is true for the "EV" indicator that appears on the display. I know many disagree with me, but this topic seems to keep coming up, so I will make a detailed case for my opinion below. If you prefer not to read it and to just continue to disagree that is okay too

First, to review some terminology in case not everyone is familiar with all of them:

Clarity is a PHEV (Plug-in Hybrid Electric Vehicle). Both PHEV and BEV (Battery Electric Vehicle) are part of a category called PEV (Plug-in Vehicle). BEV's, PHEV's and HEV's (Hybrid Electric Vehicle) are part of an even larger category called EV (Electric Vehicle), which includes among other things electric trolleys and electric trains. However in common usage EV is also used as an alternative name for BEV.

PHEV's are categorized alongside BEV's for regulatory reasons related to emissions. That and the fact that they can plug in to charge the battery, and can drive at normal speeds on electric power only, leads us to think of them as BEV's that happen to have a gas engine. But I would argue that in operation a PHEV acts more like an HEV than a BEV. As I go through some detail on how a couple of leading HEV's work I think you will start to see the striking similarities compared to Clarity in how they use and name their two primary modes, EV Mode and HV Mode.

HEV's like Prius and Insight have a mode called EV which represents behavior similar to, but not exactly like a BEV. In fact both have an "EV" button that you can push to turn on EV mode. Does that mean you can now zip down the freeway in an Insight or Prius in EV bliss? No, in both cars the size of the electric motor and the battery allow EV mode to only be used in very limited power ranges, generally related to slower residential streets or brief periods of stop and go traffic. With careful acceleration you can get to slightly faster speeds in EV mode without ICE coming on (sound familiar?). However in any event you cannot maintain EV mode indefinitely because of the limited battery capacity. At a predetermined battery level the car will automatically switch to HV mode (also sound familiar?). In fact the Insight manual refers to it as HV mode.

Both the Prius and Insight have indicators on the dash for "EV Mode", and also a different indicator for "EV". Below is a screenshot from their owners manuals. Other than the words "Insight" and "Prius" all of the text in the screenshot came from the manuals:

For each car the "EV Mode" indicator only comes on when you press the EV button. Meanwhile the "EV" indicator can come on in either EV or HV mode, it indicates that the car is being propelled solely by the electric motor (sound fam.... nevermind).

Insightman, I am not sure how the original Insight displays things? Also I am not sure how other hybrids display things either, but since Insight and Prius are descendants of the original hybrids I think they are a good representation (I know there were previous hybrids, I am referring to mass produced).

When not in EV mode, these hybrids act as, well hybrids. As I mentioned the Insight manual even refers to this as HV mode. The electric motor is used in combination with the gas engine (ICE), drawing on battery power as needed, then recharging it via ICE or through regeneration, always attempting to maintain the predetermined battery level. While in HV mode the vehicle can operate on battery alone, although at lower speeds and power levels than EV mode, and only while the battery charge remains above a set level. With enough regeneration, or moderate driving allowing engine charging, the battery level will increase and EV mode can again be selected. And anytime while driving in EV mode it can be turned off by pressing the EV button which returns to HV mode.

Realistically, the limited speed and range of EV mode in an HEV means that it is only used for things like driving through a neighborhood quietly without running ICE, although some advanced users believe they can improve efficiency by strategically using the EV mode switch to control when ICE is running, although to a more limited extent due to the small battery.

Okay so now we have PHEV vehicles like the Clarity. I have already mentioned the similarities in operation to HEV vehicles, the difference is mainly in scale. The Clarity has a much larger battery so you can remain in EV mode to much higher levels of acceleration and speed, enough power for most types of driving. And you can remain in EV mode for much longer periods. However similar to an HEV, above a certain level of power demand it will automatically switch from EV mode to HV mode. It will also switch to HV mode when EV range is reduced to a preset level (displayed as "0" even though the battery is not depleted).

Once in HV mode the system will essentially behave like an HEV and try and maintain a predetermined level of battery charge. One difference of course is that if EV range is above 0 when switching to HV mode, it will try and maintain the battery level that existed when EV mode was exited.

And yes you can start making a list of other differences, one is that you can manually control charging of the battery via Charge Mode. And Clarity sort of reverses the indicators, the single button is used to select HV mode not EV mode. And HV mode not EV mode is indicated on the display. However similar to Insight and Prius the EV indicator appears whenever the car is operating solely on electricity, whether in HV or EV mode.

But in the end, Clarity, Insight and Prius all use EV and HV modes in pretty much the same way, differing only by the more powerful electric motor, the much larger battery capacity of the Clarity and of course the ability to start with that battery fully charged.

And then there's the Volt. The Volt was considered by many as the gold standard for what EV mode means, because while driving the Volt in EV mode (referred to as Normal mode in the Volt) ICE will never come on as long as you have sufficient battery charge. Well never say never because there are a few somewhat rare situations where ICE will come on even in Normal mode, however they are not related to power demand. But that is because GM chose not to make it possible to use the accelerator pedal on the Volt to automatically combine ICE and battery for additional power. You can apparently gain a small amount of additional power by switching to Hold mode, which is like HV mode and will start up ICE and maintain existing EV charge for later use. However from what I understand you wouldn't normally switch to Hold mode just to gain additional power when for example accelerating onto the freeway. Note that I haven't driven a Volt so anyone who has please correct me if I have this part of it wrong.

Because the Volt required manual switching to HV mode, it avoided accidentally turning on ICE by aggressive accelerating. It also didn't have as many of the quirky ICE start up scenarios that Clarity has such as when regen is used on a full battery. These occasional and usually brief ICE startups result in a very small additional amount of gas usage, as documented by the Clarity owners who do most of their driving in EV. Yet the fact that these startups happen at all causes many people to have the opinion that only Volt operated in "true" EV mode, and for cars like Clarity EV mode is misnamed. But as I have detailed, the terminology for EV mode in a hybrid is pretty well established, and the fact that Volt does it differently is to be commended but in my opinion doesn't make the definition of EV mode as used by Clarity wrong. And anyway the Volt is no longer the standard because it was discontinued earlier this year, and to my knowledge there are no other cars like it or planned (other than rumors of a Volt-like SUV). There is the BMW i3 REx that also stays firmly fixed in EV mode, but it only has a small gasoline engine that is intended more as an emergency backup, allowing you to reach a charging station at somewhat reduced power than when driving in EV mode. All other PHEV vehicles to my knowledge such as Prius Prime, Hyundai Ioniq, Kia Optima and Hyundai Sonata, all start up ICE when you use the accelerator pedal aggressively in EV mode.

 

[MajorAward]

I actually think the terms EV Mode and HV Mode are correct as used on the Clarity, because each mode represents behavior similar to, but not exactly like a different category of vehicle. And it is consistent with how other hybrids use these terms. The same is true for the "EV" indicator that appears on the display. I know many disagree with me, but this topic seems to keep coming up, so I will make a detailed case for my opinion below. If you prefer not to read it and to just continue to disagree that is okay too

First, to review some terminology in case not everyone is familiar with all of them:

Clarity is a PHEV (Plug-in Hybrid Electric Vehicle). Both PHEV and BEV (Battery Electric Vehicle) are part of a category called PEV (Plug-in Vehicle). BEV's, PHEV's and HEV's (Hybrid Electric Vehicle) are part of an even larger category called EV (Electric Vehicle), which includes among other things electric trolleys and electric trains. However in common usage EV is also used as an alternative name for BEV.

PHEV's are categorized alongside BEV's for regulatory reasons related to emissions. That and the fact that they can plug in to charge the battery, and can drive at normal speeds on electric power only, leads us to think of them as BEV's that happen to have a gas engine. But I would argue that in operation a PHEV acts more like an HEV than a BEV. As I go through some detail on how a couple of leading HEV's work I think you will start to see the striking similarities compared to Clarity in how they use and name their two primary modes, EV Mode and HV Mode.

HEV's like Prius and Insight have a mode called EV which represents behavior similar to, but not exactly like a BEV. In fact both have an "EV" button that you can push to turn on EV mode. Does that mean you can now zip down the freeway in an Insight or Prius in EV bliss? No, in both cars the size of the electric motor and the battery allow EV mode to only be used in very limited power ranges, generally related to slower residential streets or brief periods of stop and go traffic. With careful acceleration you can get to slightly faster speeds in EV mode without ICE coming on (sound familiar?). However in any event you cannot maintain EV mode indefinitely because of the limited battery capacity. At a predetermined battery level the car will automatically switch to HV mode (also sound familiar?). In fact the Insight manual refers to it as HV mode.

Both the Prius and Insight have indicators on the dash for "EV Mode", and also a different indicator for "EV". Below is a screenshot from their owners manuals. Other than the words "Insight" and "Prius" all of the text in the screenshot came from the manuals:

View attachment 5164

For each car the "EV Mode" indicator only comes on when you press the EV button. Meanwhile the "EV" indicator can come on in either EV or HV mode, it indicates that the car is being propelled solely by the electric motor (sound fam.... nevermind).

Insightman, I am not sure how the original Insight displays things? Also I am not sure how other hybrids display things either, but since Insight and Prius are descendants of the original hybrids I think they are a good representation (I know there were previous hybrids, I am referring to mass produced).

When not in EV mode, these hybrids act as, well hybrids. As I mentioned the Insight manual even refers to this as HV mode. The electric motor is used in combination with the gas engine (ICE), drawing on battery power as needed, then recharging it via ICE or through regeneration, always attempting to maintain the predetermined battery level. While in HV mode the vehicle can operate on battery alone, although at lower speeds and power levels than EV mode, and only while the battery charge remains above a set level. With enough regeneration, or moderate driving allowing engine charging, the battery level will increase and EV mode can again be selected. And anytime while driving in EV mode it can be turned off by pressing the EV button which returns to HV mode.

Realistically, the limited speed and range of EV mode in an HEV means that it is only used for things like driving through a neighborhood quietly without running ICE, although some advanced users believe they can improve efficiency by strategically using the EV mode switch to control when ICE is running, although to a more limited extent due to the small battery.

Okay so now we have PHEV vehicles like the Clarity. I have already mentioned the similarities in operation to HEV vehicles, the difference is mainly in scale. The Clarity has a much larger battery so you can remain in EV mode to much higher levels of acceleration and speed, enough power for most types of driving. And you can remain in EV mode for much longer periods. However similar to an HEV, above a certain level of power demand it will automatically switch from EV mode to HV mode. It will also switch to HV mode when EV range is reduced to a preset level (displayed as "0" even though the battery is not depleted).

Once in HV mode the system will essentially behave like an HEV and try and maintain a predetermined level of battery charge. One difference of course is that if EV range is above 0 when switching to HV mode, it will try and maintain the battery level that existed when EV mode was exited.

And yes you can start making a list of other differences, one is that you can manually control charging of the battery via Charge Mode. And Clarity sort of reverses the indicators, the single button is used to select HV mode not EV mode. And HV mode not EV mode is indicated on the display. However similar to Insight and Prius the EV indicator appears whenever the car is operating solely on electricity, whether in HV or EV mode.

But in the end, Clarity, Insight and Prius all use EV and HV modes in pretty much the same way, differing only by the more powerful electric motor, the much larger battery capacity of the Clarity and of course the ability to start with that battery fully charged.

And then there's the Volt. The Volt was considered by many as the gold standard for what EV mode means, because while driving the Volt in EV mode (referred to as Normal mode in the Volt) ICE will never come on as long as you have sufficient battery charge. Well never say never because there are a few somewhat rare situations where ICE will come on even in Normal mode, however they are not related to power demand. But that is because GM chose not to make it possible to use the accelerator pedal on the Volt to automatically combine ICE and battery for additional power. You can apparently gain a small amount of additional power by switching to Hold mode, which is like HV mode and will start up ICE and maintain existing EV charge for later use. However from what I understand you wouldn't normally switch to Hold mode just to gain additional power when for example accelerating onto the freeway. Note that I haven't driven a Volt so anyone who has please correct me if I have this part of it wrong.

Because the Volt required manual switching to HV mode, it avoided accidentally turning on ICE by aggressive accelerating. It also didn't have as many of the quirky ICE start up scenarios that Clarity has such as when regen is used on a full battery. These occasional and usually brief ICE startups result in a very small additional amount of gas usage, as documented by the Clarity owners who do most of their driving in EV. Yet the fact that these startups happen at all causes many people to have the opinion that only Volt operated in "true" EV mode, and for cars like Clarity EV mode is misnamed. But as I have detailed, the terminology for EV mode in a hybrid is pretty well established, and the fact that Volt does it differently is to be commended but in my opinion doesn't make the definition of EV mode as used by Clarity wrong. And anyway the Volt is no longer the standard because it was discontinued earlier this year, and to my knowledge there are no other cars like it or planned (other than rumors of a Volt-like SUV). There is the BMW i3 REx that also stays firmly fixed in EV mode, but it only has a small gasoline engine that is intended more as an emergency backup, allowing you to reach a charging station at somewhat reduced power than when driving in EV mode. All other PHEV vehicles to my knowledge such as Prius Prime, Hyundai Ioniq, Kia Optima and Hyundai Sonata, all start up ICE when you use the accelerator pedal aggressively in EV mode.

After reading this and other posts from the past few days, I am convinced you, @insightman , @KentuckyKen , and several others on this forum have a better way of explaining how the Clarity works than the current owners manual. Honda should offer you guys a consulting gig for the all-new-and-improved-longer-lower-wider dilithium powered 2020 Clarity.

 

[Clarity_Newbie]

Indeed it does. I'm quite familiar with the interfaces and have no trouble personally knowing when the ICE is running.

My point is that for the inexperienced owner, the EV symbol is confusing. Having an EV symbol indicate when the motor is not running is poor user interface design.

Clarity Dave

Agreed.

 

[Clarity Dave]

I actually think the terms EV Mode and HV Mode are correct as used on the Clarity, because each mode represents behavior similar to, but not exactly like a different category of vehicle. And it is consistent with how other hybrids use these terms. The same is true for the "EV" indicator that appears on the display. I know many disagree with me, but this topic seems to keep coming up, so I will make a detailed case for my opinion below. If you prefer not to read it and to just continue to disagree that is okay too

First, to review some terminology in case not everyone is familiar with all of them:

Clarity is a PHEV (Plug-in Hybrid Electric Vehicle). Both PHEV and BEV (Battery Electric Vehicle) are part of a category called PEV (Plug-in Vehicle). BEV's, PHEV's and HEV's (Hybrid Electric Vehicle) are part of an even larger category called EV (Electric Vehicle), which includes among other things electric trolleys and electric trains. However in common usage EV is also used as an alternative name for BEV.

PHEV's are categorized alongside BEV's for regulatory reasons related to emissions. That and the fact that they can plug in to charge the battery, and can drive at normal speeds on electric power only, leads us to think of them as BEV's that happen to have a gas engine. But I would argue that in operation a PHEV acts more like an HEV than a BEV. As I go through some detail on how a couple of leading HEV's work I think you will start to see the striking similarities compared to Clarity in how they use and name their two primary modes, EV Mode and HV Mode.

HEV's like Prius and Insight have a mode called EV which represents behavior similar to, but not exactly like a BEV. In fact both have an "EV" button that you can push to turn on EV mode. Does that mean you can now zip down the freeway in an Insight or Prius in EV bliss? No, in both cars the size of the electric motor and the battery allow EV mode to only be used in very limited power ranges, generally related to slower residential streets or brief periods of stop and go traffic. With careful acceleration you can get to slightly faster speeds in EV mode without ICE coming on (sound familiar?). However in any event you cannot maintain EV mode indefinitely because of the limited battery capacity. At a predetermined battery level the car will automatically switch to HV mode (also sound familiar?). In fact the Insight manual refers to it as HV mode.

Both the Prius and Insight have indicators on the dash for "EV Mode", and also a different indicator for "EV". Below is a screenshot from their owners manuals. Other than the words "Insight" and "Prius" all of the text in the screenshot came from the manuals:

View attachment 5164

For each car the "EV Mode" indicator only comes on when you press the EV button. Meanwhile the "EV" indicator can come on in either EV or HV mode, it indicates that the car is being propelled solely by the electric motor (sound fam.... nevermind).

Insightman, I am not sure how the original Insight displays things? Also I am not sure how other hybrids display things either, but since Insight and Prius are descendants of the original hybrids I think they are a good representation (I know there were previous hybrids, I am referring to mass produced).

When not in EV mode, these hybrids act as, well hybrids. As I mentioned the Insight manual even refers to this as HV mode. The electric motor is used in combination with the gas engine (ICE), drawing on battery power as needed, then recharging it via ICE or through regeneration, always attempting to maintain the predetermined battery level. While in HV mode the vehicle can operate on battery alone, although at lower speeds and power levels than EV mode, and only while the battery charge remains above a set level. With enough regeneration, or moderate driving allowing engine charging, the battery level will increase and EV mode can again be selected. And anytime while driving in EV mode it can be turned off by pressing the EV button which returns to HV mode.

Realistically, the limited speed and range of EV mode in an HEV means that it is only used for things like driving through a neighborhood quietly without running ICE, although some advanced users believe they can improve efficiency by strategically using the EV mode switch to control when ICE is running, although to a more limited extent due to the small battery.

Okay so now we have PHEV vehicles like the Clarity. I have already mentioned the similarities in operation to HEV vehicles, the difference is mainly in scale. The Clarity has a much larger battery so you can remain in EV mode to much higher levels of acceleration and speed, enough power for most types of driving. And you can remain in EV mode for much longer periods. However similar to an HEV, above a certain level of power demand it will automatically switch from EV mode to HV mode. It will also switch to HV mode when EV range is reduced to a preset level (displayed as "0" even though the battery is not depleted).

Once in HV mode the system will essentially behave like an HEV and try and maintain a predetermined level of battery charge. One difference of course is that if EV range is above 0 when switching to HV mode, it will try and maintain the battery level that existed when EV mode was exited.

And yes you can start making a list of other differences, one is that you can manually control charging of the battery via Charge Mode. And Clarity sort of reverses the indicators, the single button is used to select HV mode not EV mode. And HV mode not EV mode is indicated on the display. However similar to Insight and Prius the EV indicator appears whenever the car is operating solely on electricity, whether in HV or EV mode.

But in the end, Clarity, Insight and Prius all use EV and HV modes in pretty much the same way, differing only by the more powerful electric motor, the much larger battery capacity of the Clarity and of course the ability to start with that battery fully charged.

And then there's the Volt. The Volt was considered by many as the gold standard for what EV mode means, because while driving the Volt in EV mode (referred to as Normal mode in the Volt) ICE will never come on as long as you have sufficient battery charge. Well never say never because there are a few somewhat rare situations where ICE will come on even in Normal mode, however they are not related to power demand. But that is because GM chose not to make it possible to use the accelerator pedal on the Volt to automatically combine ICE and battery for additional power. You can apparently gain a small amount of additional power by switching to Hold mode, which is like HV mode and will start up ICE and maintain existing EV charge for later use. However from what I understand you wouldn't normally switch to Hold mode just to gain additional power when for example accelerating onto the freeway. Note that I haven't driven a Volt so anyone who has please correct me if I have this part of it wrong.

Because the Volt required manual switching to HV mode, it avoided accidentally turning on ICE by aggressive accelerating. It also didn't have as many of the quirky ICE start up scenarios that Clarity has such as when regen is used on a full battery. These occasional and usually brief ICE startups result in a very small additional amount of gas usage, as documented by the Clarity owners who do most of their driving in EV. Yet the fact that these startups happen at all causes many people to have the opinion that only Volt operated in "true" EV mode, and for cars like Clarity EV mode is misnamed. But as I have detailed, the terminology for EV mode in a hybrid is pretty well established, and the fact that Volt does it differently is to be commended but in my opinion doesn't make the definition of EV mode as used by Clarity wrong. And anyway the Volt is no longer the standard because it was discontinued earlier this year, and to my knowledge there are no other cars like it or planned (other than rumors of a Volt-like SUV). There is the BMW i3 REx that also stays firmly fixed in EV mode, but it only has a small gasoline engine that is intended more as an emergency backup, allowing you to reach a charging station at somewhat reduced power than when driving in EV mode. All other PHEV vehicles to my knowledge such as Prius Prime, Hyundai Ioniq, Kia Optima and Hyundai Sonata, all start up ICE when you use the accelerator pedal aggressively in EV mode.

Well laid out, 2002. So, in the Clarity, Honda was being consistent with the Insight and Prius in its use of an EV indicator. I still find it an unfortunate choice but consistency takes precendence over many other factors in UI design. It's a good thing there are forums like this populated by dedicated and informed drivers to clear up the confusion made by inadequate manuals and UIs!

 

[CyberDyneSystems]

Thanks, the big difference between the Clarity (and Insight?) and the Prius Prime, is that the Prime has an EV mode button! But yes, even if you never press that button,. the behavior with the indicators is just as 2002 described. This coupled with 2002's description means I will adjust to the new Clarity much faster.
Thank you so much!