Ridiculous Review of the Clarity
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DaleL
Well-Known Member
As I understand it, the engine is coupled to a generator with a 60 hp generation capacity. The battery can supply the equivalent of 121 hp. Those two together can fully power the 181 hp drive motor. However, Honda also allows the 103 hp engine to directly couple with the drive train between 45 and 65 mp for more passing acceleration. 103 plus 121 should equal 224, but although the generator puts out 60 hp equivalent in electricity, there is some power lost in the conversion. It takes more than 60 hp ICE power to produce 60 hp equivalent of electricity. Thus the 212 hp peak is probably a close approximation and peaks close to the engine's rpm limit near 65 mph.
If I floor the accelerator to pass while the Engine Drive clutch is engaged, my Clarity disengages the clutch and switches from Engine Drive mode to Hybrid Drive mode, which maxes out at 181 hp. Does your Clarity instead stay in "gear mode" and shoot forward with greater acceleration than when you floor it in Hybrid Drive mode?
As I understand it, Engine Drive mode is included for greater fuel economy, not greater acceleration.
Ray B
Well-Known Member
'Gear mode', as we all know, means that the engine is physically linked to the wheels. If you connect an OBD scanner you can observe that the approximate ratio is 36.5 RPM/mph. I have never observed this Engine drive mode above ~73 mph (~2650 RPM) where you would expect the Power to be maybe less than half of the maximum. Even if Engine Drive Mode went as high as 80+ mph, the RPMs would still be in the mid-range of the engine, and approximately at half the maximum power output. On top of that every published instance of the description of this mode by Honda declares that Engine drive mode is for efficiency reasons only. Every curve that they show torque and power output makes it clear that this mode in the Clarity PHEV is only available under low power load demand, and when more power is requested it shuts off (clutch is disengaged).
Honda has not, as far as I am aware, explained how they arrive at the 212 hp figure, but it is clearly (to me) not due to some configuration involving engine drive mode.
Honda has not, as far as I am aware, explained how they arrive at the 212 hp figure, but it is clearly (to me) not due to some configuration involving engine drive mode.
The best explanation for the 212 hp I've read on this forum is that the Clarity PHEV using its low-loss 181-hp hybrid drivetrain can perform as well as it would with a 212 hp engine with a multi-speed transmission. Somewhere, a Honda engineer brewed up a set of calculations to justify that number to make marketing happy.
Marketing probably wanted to add the 103 hp and 181 hp and claim 284 hp. Engineering reacted, "Whoa, Nellie! You can't say that. We won't go along with anything greater than 212 hp and while you're writing up your brochures you can use that same made-up number for the Clarity PHEV, the Accord Hybrid, and the CR-V Hybrid, too."
"Can we say the Insight produces 212 hp, too?"
"No."
Marketing probably wanted to add the 103 hp and 181 hp and claim 284 hp. Engineering reacted, "Whoa, Nellie! You can't say that. We won't go along with anything greater than 212 hp and while you're writing up your brochures you can use that same made-up number for the Clarity PHEV, the Accord Hybrid, and the CR-V Hybrid, too."
"Can we say the Insight produces 212 hp, too?"
"No."
ClarityBill
Well-Known Member
I have driven in Gear mode at 85 MPH. Stays locked in normally.
Ray B
Well-Known Member
Just another note on the 212 hp topic, both the 2020 Accord Hybrid and the upcoming 2020 CRV Hybrid both have the similar iMMD powertrain but with 2.0L engine listed at 143 hp, but both models also still claim a 181 hp electric drive motor and a 'total system power' of 212 hp.
craze1cars
Well-Known Member
Here’s my take on the hp thing. The battery alone pushing the electric motor is able to output the equivalent of 181 hp to the wheels with engine off. And with the engine running at redline rpm the generator allows an additional 31 hp to also reach the electric motor, allowing a bit more boost for floored-to-the board acceleration, with the rest of the electric the generator is producing going back into the batter, at the same time the battery is outputting it’s max.
The hp of the engine itself is irrelevant, because anytime your foot is to the floor the engine is uncoupled and all power to the drive wheels is coming from the electric motor.
Essentially the car has an electric motor that normally is governed electronically to provide 181 up to the wheels max. Unless engine kicks in full bore. When that happens the electric motor is allows to put out 212hp for as long as you choose to keep the go pedal mashed to the floorboard.
That’s how I understand it operates. And I could be misunderstanding...
The hp of the engine itself is irrelevant, because anytime your foot is to the floor the engine is uncoupled and all power to the drive wheels is coming from the electric motor.
Essentially the car has an electric motor that normally is governed electronically to provide 181 up to the wheels max. Unless engine kicks in full bore. When that happens the electric motor is allows to put out 212hp for as long as you choose to keep the go pedal mashed to the floorboard.
That’s how I understand it operates. And I could be misunderstanding...
With the engine off, the Clarity PHEV's battery can provide only enough electricity for the traction motor to produce 121 hp. The 181 hp number requires the engine to be powering the starter motor/generator.
Somebody needs to pull out the battery and everything under the Clarity PHEV's hood, then install a conventional 212-hp engine and transmission and add enough bricks to make it weigh the same. Then they can stage a drag race against an unmodified Clarity PHEV to answer this burning question.
It would be so much easier if Honda would explain.
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craze1cars
Well-Known Member
OK I'll gladly accept that. If the 121 HP number is true on battery alone (I said 181 earlier), my math obviously changes, but my understanding of the concept of where these numbers come from remains the same...
So you get 121 HP on battery output alone. Then cram foot to floor, or far enough to the floor to engage the ICE, and now there is up to another 91 HP of additional electricity available coming from the generator, along with the 121 coming from the battery, to provide extra boost to the electric motor to a max of 212 HP in short spurts, until the gas pedal is released to the point that less than 121 HP is needed...then the engine shuts off because the extra boost isn't needed.
Again, the fact that the ICE can provide X amount of HP is a meaningless number from a vehicle acceleration/performance standpoint. Because the ICE's primary purpose is to charge the battery, not to propel the car.
I do believe it’s a mostly marketing thing. HP is a pretty irrelevant number in electric cars, but the public needs desperately to figure out how performance will compare to a normal ICE car, so mfrs desperately need to give them a reasonable sounding hp number to allow this comparison and inspire any hope of sales to the masses...
Honda has chosen 212. It might be arbitrary. Might be based on a chassis dyno that was run...I frankly doubt we will ever know and I don’t care that much. It just a number. Either the car is quick enough for a person’s tastes, or it’s not.
So you get 121 HP on battery output alone. Then cram foot to floor, or far enough to the floor to engage the ICE, and now there is up to another 91 HP of additional electricity available coming from the generator, along with the 121 coming from the battery, to provide extra boost to the electric motor to a max of 212 HP in short spurts, until the gas pedal is released to the point that less than 121 HP is needed...then the engine shuts off because the extra boost isn't needed.
Again, the fact that the ICE can provide X amount of HP is a meaningless number from a vehicle acceleration/performance standpoint. Because the ICE's primary purpose is to charge the battery, not to propel the car.
I do believe it’s a mostly marketing thing. HP is a pretty irrelevant number in electric cars, but the public needs desperately to figure out how performance will compare to a normal ICE car, so mfrs desperately need to give them a reasonable sounding hp number to allow this comparison and inspire any hope of sales to the masses...
Honda has chosen 212. It might be arbitrary. Might be based on a chassis dyno that was run...I frankly doubt we will ever know and I don’t care that much. It just a number. Either the car is quick enough for a person’s tastes, or it’s not.
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That would be quite a time consuming and costly endeavor that would only demonstrate which vehicle crossed the finish line first. It would not answer the HP question. Should anyone decide to do this, I will make a reasonable offer for the batteries.
A Dyno would yield quick, low cost results and may provide enough information to determine the amount of power being provided from each energy source on the vehicle.
My understanding, and experience, thus far, with the ICE is that it provides 4 distinct functions.
1) Provides additional power to the electric motor via the generator.
2) Maintains battery SOC when in HV mode
3) Provides a dedicated battery charge capability when in HV+ mode.
4) Provides power to the drive wheels when in Gear mode.
I still support the 121/60/31 theory, with some added speculation that the power to the electric motor could be controlled as power from the ICE fluctuates, thereby limiting maximum power to 212. I am skeptical that the 181hp motor could produce 212hp, given Honda’s conservative approach to almost everything. Unless it is actually a 212hp motor, which would require the generator to provide 91hp to the motor.
Does anyone know the rated output of the generator?
ClarityBill
Well-Known Member
The electric motors in my factory have a rated HP, but the overload systems have time delays that will allow the motor to run at 20% over rating (212 is 17% over 181). This is industry standard for electric motors.
Ray B
Well-Known Member
With 121 hp available from the battery and 103 hp available from the engine, and a claimed max power through the motor of 181 hp. Many conclude that the extra 31 hp is through direct connection of the engine through the wheels via the clutch. My only point is that this is not possible since to get the 212 - 121 = 91 hp from the engine, you'd need to be at ~5000+ RPM, which would mean if the clutch was engaged the car would have to be going ~137+ mph. That is the only point I have tried to put forward. At those load demands it is only possible through HV (series) mode. I believe Honda stated that Engine drive mode is only available between 70 and 120 kph.
There is an excess of power (121 hp + 103 hp = 224 hp) to draw from, but they claim it should all go through a motor with 181 hp max, and then claim 212 hp total peak power. The only other means is if 212 hp is a short burst peak power of the motor (electrical power from the generator and battery through the PCU/VCU), while 181 hp is the sustainable maximum power. This is the only other way that makes sense to me.
And yes, it could just be marketing exercise in creative engineering math, because Toyota (for one) claims 208 hp in their Camry Hybrid, so Honda couldn't step up to the plate and say "yes, put us down for 181 hp." for the Clarity PHEV, The Accord Hybrid and the CRV Hybrid, which all have 181 hp drive motors. Toyota is probably playing the same game on their side. .
There is an excess of power (121 hp + 103 hp = 224 hp) to draw from, but they claim it should all go through a motor with 181 hp max, and then claim 212 hp total peak power. The only other means is if 212 hp is a short burst peak power of the motor (electrical power from the generator and battery through the PCU/VCU), while 181 hp is the sustainable maximum power. This is the only other way that makes sense to me.
And yes, it could just be marketing exercise in creative engineering math, because Toyota (for one) claims 208 hp in their Camry Hybrid, so Honda couldn't step up to the plate and say "yes, put us down for 181 hp." for the Clarity PHEV, The Accord Hybrid and the CRV Hybrid, which all have 181 hp drive motors. Toyota is probably playing the same game on their side. .
Ray B
Well-Known Member
Agreed
craze1cars
Well-Known Member
Agreed. BUT...maybe the clutch is designed to slip at 5000 rpm wot...instead of lock to the engine like it does in low rpm gear mode. Or the “clutch” is actually a lockup torque converter? This concept could work.
Possible. I don’t see it as likely. But top fuel dragsters go from zero to 300 mph in less than 4 seconds with a single speed transmission and zero tire spin by simply slipping the clutch the whole way...
So just maybe when you put your foot to the floor and the engine starts screaming, it is actually driving the wheels thru a slipping clutch? Or a torque converter?
That would put the “CVT” in ECVT....
Like you I still think the electric motor is simply putting out more power for short bursts when floored. But slipping the clutch or torque converter could accomplish the same.
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Ok, the 181hp motor can temporarily provide 212hp. It will need to receive sufficient voltage and current from the ICE driven generator to provide 91hp to reach that figure. The batteries provide 121hp. Is the ICE generator capable of providing that?
Ray B
Well-Known Member
I can't find a definitive answer on that. However, I have a paper on the previous iMMD version (2014 Accord PHEV - Japan only?), that has the electric motor at 124 KW and the generator at 110 kW (166 hp and 147.5 hp respectively). We know that subsequent iMMD versions have the 181 hp motor, but no specs on the generator - I am going to guess it is higher than 147.5 hp, but I have no evidence. If it scaled up to the same extent as the motor then it is 161 hp maximum power.
Ray B
Well-Known Member
In the video presentation Honda gave when the car was being revealed, they said the motor and generator were both made more compact (by 23%) and with 40% more power density. Which roughly translates to the 8-9% increase in output for both (the motor maximum output did go up by 9%, so the math does hold up). So 161 hp for the generator, does sound like a good estimate based on those facts.
HagerHedgie
Member
I’ll happily accept the tax credit as long as they give one dollar to any industry. I would like them to eliminate all credits and incentives for pretty much everything, in every industry imaginable out there, but that will never happen.
It takes a special kind of evil to get in to lobbying for a corporation.