Honda Clarity, the Volt Challenger

  • Thread starter Thread starter bwilson4web
  • Start date Start date
  • Replies Replies 306
  • Views Views 136K
...If HV charge can go to 12 segments (12 of 18? because zero is the lowest 2?) it sounds like HV charge can do about ~9.5 kWh of ~14 kWh. There is probably some back of the envelope value of gallons of gas to kWh for the car (e.g. weight and aerodynamics, ICE, EV characteristics) as well as an mpg for some giving conditions (the car, temperature mph, road grade)....
Why are there so many variables? For example, if gasoline is $2.40/gal, and you X miles for that gallon, then why isn't the "equivalence" how many miles can you go on 20 kWh ($2.40/$0.12) of recharging electricity?
 
If I understand the original posts, I think the proposition was that it seemed like you could get a better overall trip mpg by using Clarity's HV charge mode. It's not so much a cost question.

I think the rationale was that it appeared that you could get better overall trip miles per gallon (mpg) by combining the distance traveled by ICE while in HV charge mode with the newly gained miles in the battery (by then running out those newly minted kWh in EV mode).

Probably, if there is data that shows HV charge mode can improve overall trip mpg as compared to other modes (e.g. precharged EV miles + ICE), it's because of the crazy indications that we are getting in the range numbers.
 
ICEVs work most efficiently when they are run with "wide open throttle" (WOT), which again is how the Volt's gas motor is designed to run. In a car with a carburetor, that means both the air intake and the fuel intake are wide open. But it seems rather improbable that a PHEV is engineered that way. (Well obviously not, since all modern gasmobiles use fuel injection rather than a carburetor.) Since we know it is possible to use the accelerator to speed up and slow down, the engine cannot be fed with wide-open fuel intake at all times. Logically, therefore, a PHEV running WOT must merely mean the air intake isn't being choked, but that the amount of fuel is still being regulated to control speed.

Again, I'm not seeing how the Clarity PHEV can be more fuel-efficient by using the gas engine to propel the car and charge the battery at the same time. From a thermodynamics analysis, that sounds impossible; it would be perpetual motion. That's not to say it actually is impossible in the real world, because no engine can possibly be built to attain the theoretical maximum efficiency, so the actual energy efficiency will depend on the engineering of that particular engine. But if it really is true that the Clarity PHEV's efficiency in normal gas-powered mode is so poor that it's actually improved by using the engine to simultaneously propel the car and charge the battery pack, then something appears to be very wrong with the engineering.
-

Part of it may have to do with noise, as very high RPM may be undesirable for constant cruise speeds.

However, you should take a look at the papers I linked to on this thread.
https://insideevsforum.com/community/index.php?threads/honda-clarity-power-split.418/

In their research, on the first link they show on the Slides on page 17 "Power Management," the relation between the required system power and the road load (i.e. vehicle speed). EV only mode is in the yellow shaded area on the left. Since this design uses a fixed gear ratio in overdrive ("6th gear") of the mechanical ICE to drive wheels, the RPM of the ICE is proportional to the wheel speed. Their purpose was to remove all the frictional loses of series hybrid mode (ICE to EV generator to inverter(s) to EV traction motor, then to driving gear). If there was no benefit, then it would make sense to only use series hybrid mode here. Since it's a fixed gear, there is a specific road load that matches with the RPM of the ICE without any EV motor involvement. In this diagram it's a star. When the road load is higher or lower, the system will either be able to charge or require power to assist the ICE. The question is what is the engine RPM compared to the road load? In other words, is it optimized for 65, 75, or 80 MPH? The ICE RPM can be adjusted, but I believe they examined the fuel consumption to determine their settings as per the other charts in the papers.
 
Last edited:
I don't get all the hand-wringing over EV vs HV on the Clarity and Volt - my experience is purely anecdotal - but I just got 37 mpg on the first 180 miles and 41 on the last 120 miles of a 300 mile HV jaunt (average 75 mph on the highway). I plan to keep a close track on the KWh this week but I still think I'm in the 65-70 mpg range based on $0.12/KWh and $2.49/gal gasoline. I don't get the "superiority" of the Volt - similar EV, similar HV, and the Clarity is bigger, roomier, and better appointed inside.

But it's also not all about economics - its great to drive, quiet, smooth ride, large enough for 5 adults, and DOES reduce your carbon footprint. In fact, I love going weeks without running the ICE.

So I am going to just duck now, dodge the barbs (and corrections), and enjoy my ride.
I don’t understand it either. I’m a simple man, so if we just look at the window stickers of the two cars, we see the Clarity gets 110MPGe vs the Volt’s 106MPGe. Advantage Clarity.

Moving over to the ‘gasoline only’ side of the sticker, both are at 42mpg. Draw.

Finally, the estimated annual fuel costs on the sticker show, $650 for the Clarity and $700 for the Volt. Advantage Clarity.

Add to that the size, comfort, ride and quietness, I don’t get the hand wringing either. ;)
 
These are the same kinds of questions that came up when the Prius PHEV launched. Naturally, people want to know more about how this thing works. What's the best way to balance all of the modes to get the best (probably meaning lowest cost) experience. What gets missed sometimes is that the car is already programmed to do just that.

Many times these kinds of questions ended with the recommendation to just drive it.

But as someone who always wants to know WHY, that was seldom a satisfying response - regardless of its truth… YMMV
 
In other words, there is only so much energy available from a gallon of gas. The energy for the miles traveled by ICE, plus the additional energy converted and transferred into the battery has to add up to a total energy that is available from a gallon of gas (including the various losses and efficiencies).

I agree that it would be highly unlikely that one could improve a total trip mpg by using HV charge mode. By definition (at least because of conversion losses), I should think HV charge has to be less efficient than the combination of EV + ICE following EV depletion. It is certainly more expensive, but that might be a different question.

Thank you! You explained that so much better (or at least more succinctly) than I did.
-
 
I don't get the "superiority" of the Volt - similar EV, similar HV, and the Clarity is bigger, roomier, and better appointed inside.

I guess this was at least in part aimed at me, especially where I said:

"I realize the Honda Clarity PHEV isn't the Chevy Volt, but I hope Honda's engineering isn't that bad."

Looks like I phrased that badly, because I really wasn't trying to suggest the Clarity's engineering isn't as good as the Volt's. It is different; in fact, the way it works insofar as interaction with the driver is quite different. The Volt tries hard to make the transition between EV mode and gas-powered mode as seamless and unnoticeable as possible, whereas the Clarity PHEV -- from what I've read in discussions on this forum -- seems to give the driver more positive control over when the car is in gas-powered mode, and when it's not. That the engineering of the two models is distinct and different doesn't necessarily mean one or the other is bad, or "not as good" as the other; I can easily see that different drivers might prefer one approach or the other.

When I started out one of my longer posts talking about Volt engineering, that's mainly because I think I understand Voltec (the Volt's powertrain) to some extent, since I've read a lot about it. So I'm on much firmer ground when I talk about that. I don't understand nearly as well how the Clarity PHEV is engineered. And when I said "...I hope Honda's engineering isn't that bad," this was in the context of someone claiming that the Clarity PHEV gets better energy efficiency from a gallon of gas by both propelling the car and charging the battery pack at the same time. I seriously doubt that's true, because if it is, then that would indicate to me that the Clarity PHEV has been poorly engineered. I don't think that is true.

Furthermore, if the MPGe of the larger, heavier Clarity PHEV is better than that of the smaller, less roomy Volt, that certainly does suggest the Clarity PHEV is engineered better, at least insofar as energy efficiency goes.

Okay? I really didn't intend to be a Clarity basher. Peace be unto all you Honda fans and Clarity owners! :)
-
 
I just got my Plug-in Clarity a few weeks ago, and I love it. Great handling, I can get get by completely on electric power, and there's plenty of space. I do have a few questions that hopefully other owners can help me with:

1) How is the windshield wiper sprayer supposed to work? I actually took the car to the dealer to complain that the sprayer didn't work. I was shown how the nozzle sprays directly in front of the wiper, but I still don't understand how it works. I got some bird poop in the middle of the windshield, and the sprayer is worthless. The fluid gets wiped off immediately after hitting the windshield so that most of the rubber only hits dry glass. I actually had to get out a bucket and squeegee to clean the windshield. Is this what others are seeing? Or am I doing something wrong?

2) Is it necessary to break in the ICE? I've been driving around purely on the battery, but a friend of mine told me I need to run the ICE to break it in. If that's true, how long do I need to run the ICE? Is one tank of gas enough?

3) If I drive around for months without using any gas, will the gas go bad? I've heard that there might an automatic system to prevent the gas from going bad no matter how long it stays in the tank. Is that true?

Thanks for any insight!
 
1) I mentioned this in the Clarity Issues thread. Hold the lever for a few seconds and hopefully it will work better by forcing more fluid out, but it isn't great.

2) I don't think that's been a thing for a while. Tell your friend to quit living in the 80's :) (I should let it be known that I don't know much about how cars work so I could be full of it and your friend could be right, but I think I am right on this one)

3) This has been discussed in threads here, too. I think the consensus was it should be good for a year based on the experience of Volt owners over the years.
 
tim, great questions.
1) Can't help. We haven't used the wiper sprayer yet after 2,300 miles. That may come up more in the spring when bugs hit the windshield.

2) Very good question. In our case the ICE has been used for perhaps only 200 out of our 2,300 miles. If it is going through a break in cycle it's going to have to do it in it's own sweet time. If the equivalent of 1,000 miles of run time on the ICE is necessary for break-in it's going to take six months or more. Almost all of the time the ICE is not driving the wheels, it is charging the battery and powering the motor. So there isn't much you can do to effect the break-in. With gas cars you can refrain from rapid acceleration. There's no such function in the Clarity. So I say just drive it and forget about the ICE break-in.

3) The general opinion seems to be no. Since the gas is being sloshed around that helps keep it mixed. Some have suggested that some PHEV cars will automatically run the ICE to burn gas. I certainly hope that isn't true. I have a boat that sits with a full tank of gas station gas from about October until April, about 6 months. Some years I've remembered to add StaBil, some years not. I haven't noticed any difference one year to the next.
 
... 1) How is the windshield wiper sprayer supposed to work? I actually took the car to the dealer to complain that the sprayer didn't work. I was shown how the nozzle sprays directly in front of the wiper, but I still don't understand how it works. I got some bird poop in the middle of the windshield, and the sprayer is worthless. The fluid gets wiped off immediately after hitting the windshield so that most of the rubber only hits dry glass. I actually had to get out a bucket and squeegee to clean the windshield. Is this what others are seeing? Or am I doing something wrong?

I use mine a lot, no problems so far, and I get a perfectly good wash. It is very different from the spritzer spray types. Hold the lever in until the wipers move by themselves. Only at that point (a relatively long time to hold it, compared to conventional spritzing) is there enough fluid to wash all across the wiper blades.

No idea if it matters, but here in upstate, NY, where -27F is not unheard of for the morning drive on occasion, we have to use the RainX orange or the Prestone yellow low temperature fluid (otherwise instead of a cleaning, the windshield almost instantly goes opaque).
 
I don’t understand it either. I’m a simple man, so if we just look at the window stickers of the two cars, we see the Clarity gets 110MPGe vs the Volt’s 106MPGe. Advantage Clarity.

Moving over to the ‘gasoline only’ side of the sticker, both are at 42mpg. Draw.

Finally, the estimated annual fuel costs on the sticker show, $650 for the Clarity and $700 for the Volt. Advantage Clarity.

Add to that the size, comfort, ride and quietness, I don’t get the hand wringing either. ;)

Plus having had both gen 1 and gen 2 Volts (both wonderful cars), IMHO, the Clarity is a just nicer ride overall. It drives and feels like a much higher end car. It is really a pleasure and fun to drive as well.
 
Plus having had both gen 1 and gen 2 Volts (both wonderful cars), IMHO, the Clarity is a just nicer ride overall. It drives and feels like a much higher end car. It is really a pleasure and fun to drive as well.
The Clarity is the nicest car I've ever owned or driven. The combination of a quality ride, super quiet interior, high grade materials, quiet EV drive, comfortable seats, roomy interior, large trunk, and more makes this car a pleasure to own and drive.
 
As with all things electrical...

Curiosity.jpg

I guess this was at least in part aimed at me,...Okay? I really didn't intend to be a Clarity basher. Peace be unto all you Honda fans and Clarity owners! :)
-
My sincerest apologies if you thought I was aiming at you. In general the tech press, auto press, and those parts of the auto owner community who even know what PHEV means, are always comparing to the Volt. i don't see you as a Clarity basher at all, and in fact, my first posting about how great I thought the Clarity is were in the PriusChat forum on the Prius Prime (@jdonalds can attest to that) and most of the PriusChat crowd - a very active and great community, took it well and not as bashing. Same here - so don't stop opining.
 
Thanks for the replies and suggestions to my earlier questions. One more question. I see several people talking about how they get so many miles on so many kwh. How do these people measure the kwh hours used by the car? Is there someone on the Clarity that reports kwh? Or, are they reading some meter outside the car? I think it would be very interesting to see the kwh used myself. Thanks.
 
The only place we charge is at home where our JuiceBox records the power used every time it is connected to the car .
 
Thanks for the replies and suggestions to my earlier questions. One more question. I see several people talking about how they get so many miles on so many kwh. How do these people measure the kwh hours used by the car? Is there someone on the Clarity that reports kwh? Or, are they reading some meter outside the car? I think it would be very interesting to see the kwh used myself. Thanks.

The home version of the chargepoint 32A L2 240V EVSE gives a nice display on the imac (also, I finally found it on the iPhone app too):
Screen Shot 2018-01-10 at 10.08.56 PM.webp

It's not perfect in the sense that there are some losses between what is supplied by the charge cord apparatus, the electric vehicle supply (or service?) equipment (EVSE) (the actual charger is in the car) and how much energy actually ends up in the battery, but it's a pretty good general indication of the state of things. Here elapsed time is how long the car has been plugged in, not the time to charge it.
 
Has anyone else noticed that the app now activates preconditioning even when the car is hooked up to 120V line. It used to require 220V!. And now it activates charging as it uses electricity.

big improvement- seemed to appear when I upgraded the app.
 
Some have suggested that some PHEV cars will automatically run the ICE to burn gas. I certainly hope that isn't true. I have a boat that sits with a full tank of gas station gas from about October until April, about 6 months. Some years I've remembered to add StaBil, some years not. I haven't noticed any difference one year to the next.

There's no question that the Volt is engineered to maintain an average age of the gasoline in its fuel tank to be no older than 1 year, and that it will run the gas motor as necessary to burn off fuel to prevent it from aging beyond that point. This is well documented.

Whether or not this is really necessary, I don't know. On my grandfather's farm they kept gasoline in a storage tank that got filled quite rarely, and I never noticed any problem with the fuel, nor do I recall any discussion of that being an issue. However, it's possible that either Grandpa or my uncle did put some additive into the tank that I didn't know about.

I see there are various problems with "old" gasoline; see details here:

"Can gas really go bad?"

That article claims gasoline can start to go bad in as little as two months, and that "Fuel system stabilizer is not a cure-all and it doesn't last forever. It must be mixed with fresh gas before the vehicle is stored, not added to already old gas. It can slow down the oxidation process and keep gas fresh for as long as 12 to 15 months."

Really? Color me skeptical. I wonder if this is just quoting the press release of a company that makes fuel additive?

If it really is true, then anybody who owns a PHEV which only rarely starts the gas motor, should be adding a fuel additive every time they fill the gas tank. (Obviously not necessary on a long trip where the gas tank gets filled multiple times over a matter of days or over a week or two.) And I haven't see anyone advising that on any forum.
-
 
Last edited:
Back
Top