David Towle
Well-Known Member
Sorry that makes no sense, how could it use more gas than it does in HV mode if the engine is running less? Something sounds seriously wrong with your Sonata.
How to Improve the Clarity
- Thread starter David Towle
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craze1cars
Well-Known Member
David, Good point on how your BMW worked, I had not considered it that way.
David Towle
Well-Known Member
Here's 2 more.
1. Not 100% sure this is a design fault and not a problem with just my car, but the cruise control speed varies way too much when you come to a hill (either up or down). The speed goes down by as much as 5 mph or up as much as 3. My previous car was +/- 1 mph. It seems this should be easy with an electric motor and the instant torque.
2. The following distance with the adaptive cruise control can't be set low enough. Someone in your lane way ahead of you slows down, then you slow down. I'm probably a more aggressive driver than most Clarity owners but I'm sure someone else must be annoyed by this.
1. Not 100% sure this is a design fault and not a problem with just my car, but the cruise control speed varies way too much when you come to a hill (either up or down). The speed goes down by as much as 5 mph or up as much as 3. My previous car was +/- 1 mph. It seems this should be easy with an electric motor and the instant torque.
2. The following distance with the adaptive cruise control can't be set low enough. Someone in your lane way ahead of you slows down, then you slow down. I'm probably a more aggressive driver than most Clarity owners but I'm sure someone else must be annoyed by this.
David Towle
Well-Known Member
My guess is they intentionally did not build this as an SUV because they didn't want to sell too many and cut into the high sales and margins they get with the CRV. At its original list price I'm 90% sure this car is sold at a loss, and with the $5000 off deals now its a BIG loss.
Hi Neal,
I de-badged my car over summer when it was relatively new so the glue on the badges was still soft. I used a flat plastic trim removal tool and worked it into one end of the badge - there's probably a youtube video of someone doing it. Be careful about using a heat gun or even a strong hair dryer as you could damage the paint or the plastic plug door. Car looks much cleaner without the awkward badges. I also took off the tail badges as they were not on straight.
Btw, I gave it the Clarity Fuel Cell look with the black roof. The dealer did the tint at delivery with 30 VLT front and 20 VLT in the back.
David Towle
Well-Known Member
I agree they got the overall balance right. But given the speed problems with a depleted battery, and how little time the car spends in locked gear mode since the last software update, I think the single speed drive was not thought out thoroughly. A simplified CVT drive, with maybe a smaller than standard ratio range to keep costs and size small (say 3:1 vs normal 5:1), would have been a big improvement, much better than a bigger engine. The problem is when you use the engine to generate power, which then feeds a motor, you have 2 conversion steps which each have 5% or more losses. Kind of analogous to a torque convertor in old style automatic transmissions. These put a big hit on mpg vs a modern efficient CVT mechanical drive.
Could they have packaged even a reduced range CVT within the existing space? I don't know, maybe someone on this forum does? The car does look pretty packed already.
Now this doesn't really matter to a lot of users, if their car is used almost exclusively within the battery range. The engine is just there as an emergency/occasional backup. But I'm not one of those users so it does matter to me.
jdonalds
Well-Known Member
I have a very low opinion of CVT transmissions and won't buy a car with one. There are variations of course, such as the eCVT of the Synergy Drive of a Prius which is brilliant. But many rely on some sort of slipping design which I feel is inherently an unreliable design. There have been enough CVT fails for me to stay away.
I haven't experienced the speed problem. I feel Honda got it right for us.
jdonalds
Well-Known Member
I may be wrong about this, I haven't paid much attention to the gear icon. Since the engine is an Atkinson Cycle engine which is highly efficient at steady speeds but not so good at acceleration I think the clutch only engages when traveling at a constant speed. When accelerating the engine is disengaged.
David Towle
Well-Known Member
I just used CVT as an example because it seems to be the go-to transmission for most cars nowadays. A 2 or 3 speed planetary system might be a better option, especially since there's no need for slippage since this device doesn't have to shift until the car is well underway.
To me its not a fatal flaw for the car, just makes it so its steady speed mileage might be 2-3 mpg less than it could be. Although to more "conventional" car buyers it would help if the car behaved better when the battery runs out, I think the multiple speeds could help that problem a fair amount, although it would still likely be speed limited up hills with only 100 hp.
I believe the ice comes now for heat if it is below 10 degrees?
David Towle
Well-Known Member
Not sure what you are saying here, but it seems when I immediately put the car in HV after starting the resistance heater is forced off. If I leave it in EV I get heat within about 20 seconds, in HV its like a normal car and takes 5 minutes or so for heat from the iCE cooling system.
MPower
Well-Known Member
My 2012 Prius Plugin's heat came off the ICE so that if I wanted to drive in EV in the winter, I had to leave the heat off and just use the seat warmer. Even with a full battery, the ICE would come on more often than my Clarity so far (I haven't had it long enough to experience how it runs in hot weather yet.)
Eventually, if I was going more than a mile or two, I would have to spring for the HV and let the ICE come on although often it would come on anyway to warm up the battery. As for noise, when on the interstate and accelerating uphill, the roar of the engine was louder than anything I have experienced with the Clarity yet.
Eventually, if I was going more than a mile or two, I would have to spring for the HV and let the ICE come on although often it would come on anyway to warm up the battery. As for noise, when on the interstate and accelerating uphill, the roar of the engine was louder than anything I have experienced with the Clarity yet.
2. Its annoying sometimes that there is no mode with no regenerative braking. I would like to be able to give the right paddle one pull and have it go into this mode for maximum coasting. It should also stay in this mode until you give a pull on the left paddle.
You can coast by shifting into neutral. It's fun!
You can coast by shifting into neutral. It's fun!
Ray B
Active Member
Hi Insightman - Can you let me know where you learned about this? My understanding is different (about dropping out of Engine Drive mode when more power is demanded), but I think you've dug into this much more than me. Please let me know if you have links that can help.
When reading the SAE paper on the Clarity I believe it said that was true of the previous generation. But I could have my facts wrong.
MNSteve
Well-Known Member
I'm mystified by the algorithm that engages the direct drive (and thus turns on the gear icon). I can be on a flat stretch of highway, at the same speed, not accelerating, and sometimes I see the gear icon and sometimes I do not. You're right; as soon as I accelerate it disappears, to return in a few seconds or a few minutes. Maybe I am not seeing the slight grade but with constant speed I would expect to see the gear icon a lot more.
The certainty of my Clarity switching from the ephemeral Engine Drive mode to Hybrid Drive mode is based only on my experience. However, you've now given me the opportunity to blather on about my theories regarding the way this car's modes work.
When Honda initially revealed the specs for the Clarity Plug-In Hybrid claiming a maximum of 212 horsepower, I was extremely curious about where that number came from. Why wasn't the maximum horsepower the engine's 103 hp and the traction motor's 181 hp? I assumed it wasn't the total of these two numbers because the engine and motor develop their maximum horsepower at different RPMs and the highest value in the curve showing the additive values of these numbers was 212.
Then I learned that the traction motor required both the battery and the engine-driven starter motor/generator working together to provide enough power to drive the traction motor to its maximum 181 horsepower. Without help from the engine-driven starter motor/generator, the traction motor could produce only 121 horsepower on battery power alone. That fact made the Engine Drive mode even more mysterious to me.
I made a presentation poster for an EV car meet last summer. For this poster I expanded the i-MMD mode transistion chart created by Honda's engineers for their SAE paper. The change shows that the battery can both be charged and discharged in Engine Drive mode:
The most interesting item is that the starter motor/generator is not active in Engine Drive mode. In Engine Drive mode, when the traction motor is not sending power to the battery (ie. when accelerating), all of the power from the battery-powered traction motor (121 hp) and the engine (103 hp) is going to the wheels. Again, because Honda says that total is 212 hp, not 224 hp, I'm back to assuming that the power curves from these two devices do not peak at the same RPM number.
So when you stomp on the accelerator while traveling in Engine Drive mode, why does the Clarity PHEV go back to Hybrid Drive mode (the 181-hp engine+battery power configuration, not the user-selectable HV Mode)? The answer must be the very tall, gas-saving gear used to transfer the engine's power to the wheels does not lend itself to brisk acceleration. To accelerate quickly or climb a steep hill, the car needs to have access to lower effective gear ratios. Those lower effective gear ratios are available only in Hybrid Drive mode, when higher engine RPMs are used to generate power from the starter motor/generator. Honda conceptually refers to this use of a computer-controlled engine+motor combination as e-CVT (electronic Continuously Variable Transmission).
Some day I hope the Honda engineers will reveal how the user-selectable HV Mode chooses between the three basic underlying modes, EV Drive mode, Hybrid drive mode, and Engine Drive mode. It's possible that the fuzzy logic built into the artificial intelligence running our Clarity PHEVs cannot be explained with a simple set of rules. Programmers of high-level chess-playing programs often have no idea why their programs make the moves they do. The good thing is that it all seems to work in the Clarity PHEV.
David Towle
Well-Known Member
To summarize the mystery, if the car can propel itself down the highway fine in EV mode and its 121 hp, why can't it propel itself fine with EV plus the ICE (ie engine drive gear icon mode) especially if the battery is full? The only time on the highway it should go out of engine drive mode is downhill. The answer must have something to do with engine efficiency but in the narrow speed range of highway driving its hard to understand why.
David Towle
Well-Known Member
thanks. Can you shift back into drive at any time to regain engine braking when you need it at the end of the coast? And I do wonder if it actually provides any benefit versus moving the throttle to a neutral position, the drag of rotating an electrical motor should be nothing compared to an ICE.
PHEV Newbie
Well-Known Member
For those of us in cold climates, a really simple improvement that would be a game changer is to have a heated steering wheel. Honda already makes this exact steering wheel heated in other Hondas. With the heated seats plus a heated steering wheel, I wouldn't have to turn on the resistance heater except when the temp drops below 20 degrees F. That resistance heater is the biggest range killer.