If this is true (generator output is fixed with RPM), then I agree that there is no point in using better gas, as long as the car is not in direct drive mode. If I remember correctly the most raucous engine occurs when climbing but speed is low so the car cannot get in direct drive mode (very steep climbs with speed lower than 45 mph). But I am not sure this is the case. That means the car can generate same power regardless of elevation (sea level or 11000 ft). Being a permanent magnet doesn't mean it is fixed excitation. It would be nice if someone can find the specifications of the generator. All I saw was 105kw in a youtube video by Alex in Autos, but I am not sure it is for Accord or Clarity. The Clarity engine cannot generate 105kw.
The engine would not be capable of the same full-power at varying elevation, but it could maintain the same reduced-power through elevation changes. Assuming the engine is not at full-throttle (Probably true, if it is designed for efficiency / matched to generator at high-elevation operation): The engine, at higher elevation, would sense low O2, and open the throttle plate more, while keeping injector pulse width relatively constant (for a given RPM). The generator would not be affected by elevation. I guess that is why I posed it as a question: I don't understand how you have a separate excitation in a brushless generator. Any explanation?
Any internal combustion engine will produce less power at higher elevations. Even turbocharged engines. The specifics on the output of the generator on the Clarity are a bit of a mystery. Honda states that the generator can provide 60hp to the electric motor, in addition to the 121hp from the lithium battery. 60hp equals ~45kw. The engine is rated at 103hp or ~76.5kw. It is possible that the ICE, which drives the generator on the Clarity, could suffer a 10-20% loss of power while operating at high elevations and still provide sufficient power to the generator to produce the maximum rated output to the electric motor. The numbers indicate that ICE has ample power for the task. I am not aware of a generator that does not have a derated power output based on elevation, typically at 3000’-5000’ and above.
If you’re familiar with inverter generators, you’re familiar with the Clarity generator. Engine speed varies depending on the load. Engine Drive Mode engages at speeds above 45mph. It disengages immediately upon anything more than the slightest amount of acceleration. I have nursed it up to 85mph, but it takes a delicate foot. Uphill, flat or downhill, it will disengage when acceleration is requested. The car will never, yes, I said never, be in EDM when accelerating uphill at any speed and it will probably never be in EDM when maintaining a set speed on any grade above ~1%. Although it may be correct that the Clarity can make the same power at 11,000’ as it does at sea level, we cannot reach that conclusion without knowing the output of the generator at 11,000’. The power from the batteries will be unaffected by elevation. The YouTube genius should know that a 103hp engine equals 76.5kw. A 60kw generator would be realistic. Kohler makes a 60kw generator with a 103hp engine.
I think you missed the point of my posts. So, you are saying an engine at full-throttle at 1,000 foot elevation would produce less power than the same engine idling at sea level? I would agree that an engine has less maximum power as barometric pressure decreases (higher elevation).
It would be ridiculous to compare the power output of the same engine at full throttle to the power output at idle, at any elevation. Even I wouldn’t suggest such a thing. How could you misinterpret anything I’ve said, to reach that conclusion? The difference in maximum power from the same engine at sea level or 1000’ would be minimal, but measurable. We have been discussing an elevation of 11,000’. You’ve stated that the output of an engine will be reduced at elevation and that the generator, presumably the output, will not be affected by elevation. The generator on the Clarity may be an exception to the rule of reduced generator output at elevation. Do you have any data that shows the output of the Clarity generator at sea level and various elevations?
While we may not be able to agree on this very fun to read 91 v 87 octane ratings and its effect on the Honda Clarity, can we at least agree that adding a half a cup of water per 7 gallon tank of E10 fuel will yield the exact same results as steam injected turbines? Increases power, efficiency and lowers emissions.
Depends on how much water was 'unintentionally' added by the supplier... Also, the limit of engine / generator controls supplied by Honda. Maybe we should try this with the 'better' ethanol-free fuel. (Full disclosure: I am an ethanol producer.)
Oh darn, I forgot to put 91 octane in my Clarity today. Used 100% gasoline (87 octane) from 7-11. $2.08 per gallon. First gasoline I've pumped in the tank since 04/20/20. Sorry ClarityBill, no ethanol for me.
Inane discussions can be fun as well. How would the steam be generated from the water that is added to the fuel? A fuel/water separator? Maybe we just put water in a separate tank and save added steps and complexity. Now we need to make some steam. Hmmmmm... We’ll figure that out later. Let’s focus on injecting it into the turbine engine. That was an option on the 2020 model, correct? No? Whose idea was this? What’s in that bee smoke?
You mean like BMW M4GTS? https://www.bmw-m.com/en/topics/magazine-article-pool/5-litres-of-water-for-500-horses.html
I too have somewhat enjoyed reading this thread. I really like the idea of DIY nitrous injection. Got to be someone here who is a tinkerer who would like to try it. Also, to follow @ClarityBill's lead, for full disclosure, I am a methane producer and an alcohol consumer.
I thought I was done with the warrantee at 60K, and was getting ready to run this thing on hydrous ethanol... Looks like I am supposed to wait till 150K. I was able to convert my lawn mower to ethanol by dropping a 1/2" washer in the air cleaner. My Ford van runs fine on a 50/50 mix... (yes, I found out what happens when you go to a higher mix in my van.) I wonder how smart the Clarity really is. I generally find the alcohol consumption comes before enhanced methane production...
If only someone could demonstrate, and by that I mean prove with before and after horsepower and torque figures from a dynamometer, that any of these proposed alternative fuels, those being anything other than 87 octane and up to 15% ethanol, or internal combustion engine modifications would increase the output of the electric motor, we’d really have a breakthrough. Until then, I’ll be enjoying a variety of adult beverages and chewing my food.
Terminology of the parts of this system seem to be confusing our discussion. ICE – Gas engine Generator head – Electrical portion of the main generator set Traction motor – electric motor that can also act as regeneration generator. There are several issues under discussion, we have been mostly talking about the output of the ICE, but the electrical capacity of the generator head is a second part of the issue. The output of the Traction motor is a third section. The generator head output seems proportional to rpm. My experience: Gear mode at 78 mph is about 2850 rpm, and that generates about 5/16 of the gauge full power. The highest rpm I have driven extensively is about 4200, and it seems about 7/16 of gauge (exact proportional number). I track this by watching gauge when power flow switches from charging to discharging battery. Lower rpm has a lower switch point. This would indicate no variation in generator excitor. This looks like a pretty standard inverter generator design. The problem is when the battery is depleted, and the system needs more power, the only alternative is high rpm. The trick I have used is getting the system to reset the target for power requirement. This has been discussed as an HV reset. The role of the ICE is to turn the generator head. RPM would be set by the electrical needs of the system, and the expected rpm of the generator head. Changing efficiency or power curve of the ICE could reduce fuel consumption, but would not alter the rpm target.
Back to the OP: I have been assuming the lack of power was high rpm on the gas engine, and not a loss of speed on the grade. Has anyone recently seen loss of speed on a grade? (There were earlier problems of shutdown while driving... Different problem, but has anyone experienced that, either?)
