craze1cars
Well-Known Member
All good! We all gots our heels dug in firmly! Agree to disagree. Everyone fuel up and drive!!
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- Thread starter Agzand
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Groves Cooke
Active Member
This is almost like "what oil do I use in my vintage tractor?" I would follow the owners manual.
I may be worth it to you.
A maximum power the ICE isn’t even directly powering the wheels. It is spinning a generator that sends electricity to the traction motor. You could fuel up with 100 octane and install a nitrous tank, just don’t expect any more current to come out of the generator. The traction motor is rated at 181hp. It is powered by electricity. This is not a conventional ICE vehicle.
Is any of this sinking in?
You’re not going to get an additional 5hp out of this car. Maybe you know more than the Honda engineers. Maybe you’re the only one willing to spend time and money on premium fuel and dyno testing to find out that the Clarity is a hopeless case.
Keep us posted.
When you are in HV mode, you won't get 181 hp. You might get it for a short burst, but in order to maintain battery charge the car needs to rely on the 1.5 engine. That means you are climbing with maximum of 105 hp at 5500 rpm. Now if you can get an extra 5 hp, that means you can drop the revs a few hundred rpm, or go faster at the same rpm. I have done many long trips involving steep grades and I can tell you with certainty that in HV mode the car climbs likea 105 hp car, not like a 181 hp car.
Mowcowbell
Well-Known Member
Meanwhile, I'll keep right on putting 100% gasoline 87 octane in my Clarity. 
Dan Albrich
Well-Known Member
I'm not sure if reading this thread I've seen this posted plainly:
1) The electric motor in the Clarity is more powerful than the gas engine. So in the steepest climb's if I have EV range, I turn off hybrid mode and use all electric. I plan my trips accordingly. Short: Gas engine=weak. Electric motor= strong, rinse, lather, repeat.
2) If you exhaust the EV range due to repeated hills or mountains (which happens where I live), that's really what EV-charge mode is for. Hold that button down, go into HV charge mode and get some more EV range as needed.
1) The electric motor in the Clarity is more powerful than the gas engine. So in the steepest climb's if I have EV range, I turn off hybrid mode and use all electric. I plan my trips accordingly. Short: Gas engine=weak. Electric motor= strong, rinse, lather, repeat.
2) If you exhaust the EV range due to repeated hills or mountains (which happens where I live), that's really what EV-charge mode is for. Hold that button down, go into HV charge mode and get some more EV range as needed.
I enjoy threads with titles including gas type or oil type. I get out the popcorn and lemonade and enjoy the repartee.
Just add tire pressure.
Sometimes the easiest decisions can be the most challenging.
I've wondered about this issue myself.
The question is, would the increased octane rating allow the engine controls to run higher cylinder pressures and produce more power and generate electricity faster under high vehicle loads.
Even if it theoretically did work, you have to balance that with higher cost and the lower fuel (combustion) value of high octane rated gas.
High octane gas is formulated to burn consistently slower to avoid pinging and detonation at high cylinder pressure (high compression) but you need more of it to do the same work as low octane fuel.
The question is, would the increased octane rating allow the engine controls to run higher cylinder pressures and produce more power and generate electricity faster under high vehicle loads.
Even if it theoretically did work, you have to balance that with higher cost and the lower fuel (combustion) value of high octane rated gas.
High octane gas is formulated to burn consistently slower to avoid pinging and detonation at high cylinder pressure (high compression) but you need more of it to do the same work as low octane fuel.
The ICE drives the generator. The generator has a limited output capacity. A more powerful ICE would not increase that capacity. Output is RPM dependent. If the engine can obtain peak RPM to drive the generator to peak output on 87 Octane, that’s all we’re going to get.
Once the generator is operating the electricity is available. When it reaches maximum output the maximum amount of current is available. Nothing will make it generate electricity faster.
What would be required for more power would be a greater output of current and the ability of the electric motor to utilize that current.
Tuning an Internal Combustion Engine to generate more power, with a specific fuel, on a conventional vehicle with a transmission and driveshaft will send more power to the drive wheels. The only time the engine is connected to the drive wheels on a Clarity PHEV, is when it is making ~40hp. The engine can make 40hp on 87 Octane.
Save a dime, run 87 and learn to live with the shame of it all.
Once the generator is operating the electricity is available. When it reaches maximum output the maximum amount of current is available. Nothing will make it generate electricity faster.
What would be required for more power would be a greater output of current and the ability of the electric motor to utilize that current.
Tuning an Internal Combustion Engine to generate more power, with a specific fuel, on a conventional vehicle with a transmission and driveshaft will send more power to the drive wheels. The only time the engine is connected to the drive wheels on a Clarity PHEV, is when it is making ~40hp. The engine can make 40hp on 87 Octane.
Save a dime, run 87 and learn to live with the shame of it all.
David Towle
Well-Known Member
No the best way to maintain power is put the car in HV Charge, preferably before the climb, and let it rev. Even if you do it during the climb you'll do the best job the car can of maintaining battery charge. I charge my car exclusively on HV Charge, never plug it in, and it works great. Been getting 51-52 mpg the last few fill ups.
Assuming the generator is perfectly matched to the engine output and has no headroom (I don't believe it is the case), still you will get lower RPM from the engine, which is basically what I am trying to achieve here.
You'll just go slower.
Lower RPM’s from the ICE will result in less output from the generator.
I see your point, that would be true if the generator had a fixed excitation, but that would be too limiting, I assume the generator can regulate output, so depending on engine torque it will adjust resistance. Otherwise it has to be regulated for the weakest engine operating condition (lowest torque) which doesn't make sense.
JFon101231
Active Member
You seem convinced to try it, so go ahead.
ClarityBill
Active Member
Does this generator have fixed excitation?
Is this true: The rare earth metals used on the motor and generator mean the armature has no winding: This would represent a fixed excitation. I am familiar with older generators that had coils on the armature, and a DC excitation current.
This would fit with the engine staying in Atkinson mode (weak operating condition), even when more energy is required.
(The advantage of rare earth armatures is low rpm torque and simplicity.)
Mowcowbell
Well-Known Member
CEO's of oil companies want you to drive on Premium. All.of.you.
Perhaps your assumptions and beliefs will prove your theory to be true.
ClarityBill
Active Member
The output of the generator does seem very constant at constant RPM. I see that when the power screen switches from charging to discharging, compared to the power required for driving. It is consistently at the same point of the power meter.
If the generator does not adjust output, the engine would have to adjust output to match. The engine would adjust the amount of fuel in the cylinder to match the power output required.
The higher octane could allow a more efficient power stroke, and possibly use less fuel for the same power output.
The combination of knock sensors and O2 sensors gives the computer the tools to adjust for efficient combustion.