"Angry Bees"

[ClarityBill]

I am really hoping someone can analyze the high-rev, power-loss situation. My only experience close to that was pressing the accelerator and getting high-rpm's with no acceleration. I was stunned, but then realized I had more accelerator pedal: Pushed down more, and took off. The quick response of RPM's and engine sound threw off my perception.

I am also recording pedal position (but hide it in the posted graphs). Most of my driving is in cruise control, so the pedal position is really boring (zero).

There are also load and torque numbers that don't seem to add anything to the discussion (I can't figure out what they are). They are only active when the engine is running, but don't vary much during operation.

 

[MrFixit]

ClarityBill:

Let me test out a thought on you...

Your scenarios with unacceptable noise are almost exclusively at 73 MPH. I think it is pretty clear that 70+ MPH is definitely pushing the little ICE, and it will need to have high rev's particularly if there is hill involved (and especilly in HV_Charge like your one experiment). I have not been on a trip yet with this car where I had any kind of a sustained run with speeds that high.

There is a portion of your "HV Charge" run that is interesting. There are two regions with "flat" speed. The first one, maybe 67 MPH, and the second one at 73 MPH. The RPM's were roughly 3200 for the lower speed stretch and 3500 for the faster one. The RPM's are pretty much tracking the speed (this is not 'direct drive'... Much higher RPM's than direct for these speeds). If you had gone 60 MPH, then the RPM's would have likely dropped even more to 2800 (even lower if it had been HV instead of HV Charge). At some point the noise crosses below the threshold of unacceptable (and/or the gear comes on).

Could it be that those who mostly operate below 60 MPH largely avoid the bees and don't experience objectionable noise levels while those who frequently cross 70 MPH have a different experience?

Also, as you demonstrated, to whatever extent the gear icon can be active, that noise level will be quite good (73 MPH == 2600 RPM).

Undoubtedly there will be some instances at 60 MPH where the bees may need to swarm because of a steep hill, but these occurrences may be much less frequent and shorter duration than they will be at 70+.

I'm sure you couldn't do this without causing an accident, but it would be interesting to travel on your long uphill stretch of I88 where you have the loud noise, and do 5 minutes each at 73, 70, 65, 60, 55 to characterize the un-swarming process. Maybe at 2:00 AM, but then a cop may pull you over for going too slow !

I see no reason to believe that your car isn't operating exactly like the engineers designed it. There are clearly pieces of the operating envelope that are more attractive than others, and you are doing us a favor by helping to characterizing this envelope.

 

[ClarityBill]

Mr Fixit,

I can try out the varying speeds, I am sure it will have an impact.

But I think the SOC is the more important factor. The first 28 minutes Angry Bees 2 is the same road as the bad section of Bee Control (minutes 26-65). In Angry Bees 2 the rpm's never hit 4K, and there are sections of gear drive. In Bee Control, the rpm's go over 4K, and much of the time is over 3500. The rpm's driving this same section of road, at the same speed, are very different: The cause is the difference in SOC.

My theory: The higher SOC requires the generator to run faster to generate the voltage needed for charging. Generator voltage varies with the speed of the generator. When the SOC is lower, the battery is operating at a lower voltage: The generator can get amperage into the battery at a lower voltage, and run slower.

Angry Bees 2 shows driving 73 mph with reasonable rpm levels. It goes high for climbing grades, but not excessively.

To test out the varying speed vs SOC: I have a 60 mph drive tonight that I would normally just do in EV mode. I can do it in HV and see if the engine has to go high rpm to maintain 80-100% charge in the battery...

 

[MrFixit]

ClarityBill:

Although you could be onto something regarding SOC, I don't believe that it could have anything to do with "overcoming" the battery voltage to get the desired current. Except at the extremes (near full charge or near zero charge) there is very little change in the battery voltage across a very wide range of SOC. Here is a representative curve to illustrate...

 

[Ray B]

Cold weather will definitely limit the output of the EV battery, particularly when the SoC is low, although the ability to recharge is better at that SoC compared to a higher SoC with the same cold battery. This chart below is taken from a webpage (https://www.gs-yuasa.com/jp/deepstory/vol5.html) (and translated from Japanese) to show performance of what I believe is our Clarity EV battery (EHW5).

 

[MPower]

I think MrFixit may have something. I think speeds above 70 mph are a significant factor. It seems to me that a number of threads have contained references to unsatisfactory/excessive engine noise at high speed conditions.

I rarely go over 70 mph, but my only experience of angry bees was doing 72 mph going up hill in HV with a half full battery, temperature in the high 20Fs. The minute i reduced my speed to 67, the noise stopped even though all the other conditions remained the same.

 

[ClarityBill]

MrFixit

Looks like battery voltage cannot be the basis. But my Clarity sure seems happier with low SOC (not zero) in HV mode.

I did a quick run with some 60 mph driving. Not great test, but it did not hit 4K rpm. There were definitely some annoying bees, and the quietness of the slower driving may have made them more noticeable.

 

[MrFixit]

I assume you were HV from the start of the run? The vehicle clearly "wants" to shed some charge before stabilizing at ~90%. This seems consistent with not being able to regenerate with too high of an SOC.

Something else I find interesting is that your ICE was running virtually the entire time. It mostly cycled between 1500 and 3000, but didn't turn off at all after the 1st 8 minutes.

My data is much more limited, but when I was in HV (with zero battery), the ICE cycled on/off a good bit (well, this is only a 5 minute piece, and I was going slower than you):

 

[ClarityBill]

I was in HV mode before I moved the car, so it was the entire time.

My HV mode seems to allow some drop in SOC before maintaining the SOC, even at lower levels. Starting HV with zero battery would not allow that starting drop. Seems like the control is operating in proportional mode, with not enough integral (PID control analogy). Your chart may be just the starting period for me, while it was allowing the battery to lose a little SOC.

The non-stop ICE after 8 minutes seemed to be gear drive. I think it would drop to synchronous speed, then increase to recharge battery. I definitely saw the gear during my run... It was a two-lane road, so I wasn't able to watch closely.

 

[Clarity 4 life]

Bingo!! The engine in this car is primarily a generator. It does NOT propel the car in most circumstances. As anyone who owns a generator can attest, they FREQUENTLY run at full throttle. So the fact that this car runs it’s engine periodically at higher speeds is fully expected, and very efficient. The fact that people feel the need to somehow trick the car into slowing down the engine just baffles me...do NOT hit the EV button just to shut the engine down! When the engine is revving it is following a program, doing exactly what it needs to do in order to maintain peak efficiency and battery and engine health. Let it work! It’ll slow down when it doesn’t need to rev anymore. If the fact that the engine rpm doesn’t follow linearly with your go-pedal is that big of a problem for you, it may mean you have purchased the wrong car...but it doesn’t mean it’s not working right. On my 4200 mile road trip I hammered thru mountain passes exceeding 12,000 ft and those angry bees were screaming at times...sometimes even in downhills and other times when not expected. Yet thru these mountain passes it got a legit 50 mpg and had plenty of power when needed. And no I wasn’t sitting there switching between modes all the time which in my belief just serves to confuse the computer. Let the car make its choices, and just drive it. Yes the engine may scream high rpm at times. So what? Turn the radio up a notch or two if that bugs you...

I did a 600 miles stretch on a dead battery in EV mode at 80 mph. Performance of the car was exactly the same as another 600 mile stretch at 80 mph on a relatively full battery in HV mode. Mpg and performance exactly the same both stretches. I never once experienced a loss of hp when cramming my foot to the floor to pass on 2 lane roads or merge onto interstates, whether battery gauge was full or empty. Why? Cuz it became fully apparent to me the car is smart enough to save its own reserve, even if the gauges on the dash don’t reflect it to the driver.

It’s amazing to me how people are trying to override Honda’s programming by hitting buttons and trying to override what the car needs to do just because the engine speeds up. I firmly believe you’re accomplishing nothing, and possibly hurting efficiency...or the battery....or the engine.

Engines can rev fast and live to tell about it. Frankly it’s good for any engine that short cycles all the time like this one. High revving builds heat, purges excess moisture, runs higher oil pressure allowing lubrication to improve and preventing sludge accumulation, cleans carbon from combustion chambers, etc. it’s idling, lack of use, and constant slow rpms that cause engine damage over time. Trust the car. It knows what it’s doing. Your engine has chosen to rev high for a little while because it NEEDS to based on your usage and driving patterns. The driver doesn’t need to understand why. Just drive.

You are absolutely right.
Honda states in their videos.
Just drive like a normal car and let the car decide what is best. No way to avoid the high revs at times. Or, put it into charge mode when the battery is less than 25%.

 

[ClarityBill]

Driving last night, I hit some hills at 73 mph, after a while, the ICE started to rev, so I switched out of HV mode for less than 3 seconds, and went back into HV mode, and the ICE went back into gear mode to finish the hill. I did not accept the high rpm's that the car thought was best, the SOC charge dropped a little, but the rpm's were comfortable. (I stopped the angry bees from swarming.)

It was an extended grade, so I did this 'switch out' twice: About 74 and 76 minutes on the attached OBII graph.

(At minute 68, the rpm's came up, but the car got itself back to gear mode).

I am looking for ways to improve my comfort driving the car: I don't 'let the car decide what is best.' Maybe Honda will incorporate my operational suggestions into their future models...

 

[David Towle]

Bingo!! The engine in this car is primarily a generator. It does NOT propel the car in most circumstances. As anyone who owns a generator can attest, they FREQUENTLY run at full throttle. So the fact that this car runs it’s engine periodically at higher speeds is fully expected, and very efficient. The fact that people feel the need to somehow trick the car into slowing down the engine just baffles me...do NOT hit the EV button just to shut the engine down!

Yes its like a home generator, but usually generators are placed outdoors away from where you can hear their whining. Honda should have given us an easy way to avoid the whining by giving the option to lock the car in gear mode and use whatever battery is needed to supplement. Having to regularly switch from HV to EV to reset and prevent the whining is ridiculous.

 

[craze1cars]

I’m not saying the revving engine is quiet and pleasant. I’m just saying it’s part of normal operation in certain circumstances, and fully harmless to the car and the engine. Those who are fully annoyed by it when it happens, certainly won’t be fully pleased with this car. And that’s one primary reason why Consumer Reports disses the car, and I think rightfully so. Anyone who prioritizes silence at all times, but regularly exceeds the EV range of the Clarity and/or does a lot of high load driving at the same time, really should buy a different car. Cuz the engines gonna rev at times and that owner will not be satisfied.

But the revving engine doesn’t bother me, nor does it mean the car is defective. It is normal. Those are my primary points.

 

[MrFixit]

I don't 'let the car decide what is best

@ClarityBill:
Fundamentally it seemed like you had elected to invoke HV when your SOC had reached ~50%. This is exactly what I would do when on a trip that significantly exceeds EV range in order to retain substantial charge during a 'long' highway stretch. Then, when a charger is within reach (on the way back home for instance) go back to EV and deplete the battery just before reaching home.

Each time you exit HV (even only briefly) then return, a new setpoint is established (and it is typically, if not always lower than the prior setpoint). In your case, the two "switch outs" you did resulted in a new SOC setpoint that was closer to 40% than to 50%.

You chose to prioritize 'comfort' by trading off SOC in order to maintain lower engine RPM's. I would have prioritized maintaining the desired 50% charge and let the car do what 'it' wanted to do (that is what HV mode does - maintain SOC). The higher rev's are most often pretty short in duration and at 73 MPH, I find the higher rev's are not at all objectionable.

The Honda engineers wisely designed this car so you don't need to play around, but you certainly can if you choose to. As such, I would not advocate "incorporating your operational suggestion" at all. The hooks are already there for you to manually intervene, but I can't see changing the default operation based on your preferences.

 

[David Towle]

I’m not saying the revving engine is quiet and pleasant. I’m just saying it’s part of normal operation in certain circumstances, and fully harmless to the car and the engine. Those who are fully annoyed by it certainly won’t be fully pleased with this car. And that’s one primary reason why Consumer Reports disses the car, and I think rightfully so. Anyone who prioritizes silence at all times, but regularly exceeds the EV range of the Clarity and/or does a lot of high load driving at the same time, really should buy a different car. Cuz the engines gonna rev at times and that owner will not be satisfied.

But it would be soooo easy for Honda to add the stated option.

 

[Fast Eddie B]

I’ll post a complete report when we get back home, but yesterday we drove over 800 miles from N GA to S FL. About 80% Interstate with HV selected the entire time. Cruise control often set to 75 mph.

Engine noise was never intrusive, and usually completely inaudible.

Then again, I’m pretty close to getting fitted for hearing aids, so there’s that!

 

[ab13]

I’m not saying the revving engine is quiet and pleasant. I’m just saying it’s part of normal operation in certain circumstances, and fully harmless to the car and the engine. Those who are fully annoyed by it when it happens, certainly won’t be fully pleased with this car. And that’s one primary reason why Consumer Reports disses the car, and I think rightfully so. Anyone who prioritizes silence at all times, but regularly exceeds the EV range of the Clarity and/or does a lot of high load driving at the same time, really should buy a different car. Cuz the engines gonna rev at times and that owner will not be satisfied.

But the revving engine doesn’t bother me, nor does it mean the car is defective. It is normal. Those are my primary points.

The car prioritizes efficiency over sound, because they're trying to maximize MPG. It would possible to reduce sound at the expense of energy use. Perhaps that could be in sport mode or some such.

On the poll I made almost 70% of people came from a ICE only car, so not being used to a hybrid car that starts the engine when it needs to as a generator may be unexpected.

 

[Clarity 4 life]

I like your logic. What you are saying is that the only

I'll try explaining it differently...this isn't a perfect illustration but I quickly found a generic representation (non Honda) of how RPM relates to power generation of a typical electric generator...it is very "peaky" to use language used when describing typical torque/HP curves:
View attachment 3211

Now...apply it to the Clarity. When your ICE first fires up due to electrical demand (HV mode activated either manually or by bringing EV range to zero), the engine is running, rather slowly for a bit. The engine is just warming up...get the oil circulated and warmed up for maybe 5 minutes before putting a big load on it...at this rpm yes the engine is running, but you're still mostly burning battery and EV range continues to drop. Let's guestimate at this point it's revving at maybe 1,500 rpm and not obtrusive. It is no coincidence that most gasoline powered cars, with today's modern high-ratio gearing and overdrive, are also often running at 1,500 or 2,000 rpm all the way up to 70 mph -- this is simply what modern non-aggressive drivers have become accustomed to...an engine that rarely exceeds 2,000 rpm in most driving circumstances.

But those engines aren't spinning generators. A brave new world.

Back to the chart. Most generators have a very specific RPM they are most efficient at. Naturally Honda would target this. And as a general rule it's in the 3,000 to 3,400 rpm range, but all are different. The other consideration is trying to provide a definition of "Angry Bees". For many, it might be as low as 2,500 rpm. For others, it might be 5,000 rpm. We have no earthly idea since Honda didn't give us a tach.

As stated earlier, when the engine first fires up and is walking along at 1,500 RPM and warming up it is entirely possible it is generating only 25% of the electricity it could generate if it were running at 3,000 rpm instead, where it is most efficient at producing power. Of course spin it at 5,000 rpm and it will generate even MORE power, but maybe only 25% more while burning 2 or 3 times the gasoline...efficiency drops way off. For generators: Extremely high RPMS are not efficient. And low RPMS are ALSO not efficient. Mid-range RPMS are most efficient.

So knowing this, what is the most efficient between these 3 options: Run the engine at 1,500 rpm for 4 hours? Or run the engine at 3,000 rpm for 1 hour? Or run the engine at 5,000 rpm for 45 minutes? All three produce the same amount of electricity in the end. Option 1 is more pleasant and quiet. But the 3,000 rpm run for 1 hour would burn less gasoline than either of the other 2 options. This is what Honda programmed into the car. And for this reason, I believe on typical high-speed interstate runs in HV mode...AND SOMETIMES AROUND TOWN...this engine very likely running in the 3,000 rpm range periodically -- and by design -- because it is the most efficient rpm for producing electricity after the engine warms up. The car's goal is to spin a higher RPM for a shorter period of time to save gasoline, charge the battery as fast as reasonable, and shut itself off so you can go back to saving yet more fuel -- and SOME owners report "angry bees" at this 3,000 rpm level because for the past 20 years they've been driving cars that walk along at 1,500 to 1,800 rpm at 70 mph...and cars that NEVER spin 3,000 rpm while coasting down a hill -- like the Clarity might occasionally do.

For those who wait for the engine to warm up, then it starts to rev, and it bothers them so they hit the EV button a couple times and then switch back to HV just for the sake of shutting down the engine noise? I think you're being simply wasteful -- confusing the computer and starting the engine warm-up process over again. If the car is allowed to rev a bit more it's converting gasoline into electricity in the most efficient manner. But the average driver doesn't get that, and thinks the engine is simply revving too fast. It's not.

No question when I was hammering to the top of a 12,000 foot mountain pass, I was way up in the 5,000 to 5,500 rpm range on this car. The generator was producing as much electricity as it possibly could, but certainly not efficiently...it was just tapped out. And this was evident by looking at the live MPG meter (this is the best representation we have on this car of a tach) and seeing it was getting less than 15 mpg on the way up. Those weren't "angry bees", those were "irate bees screaming for bloody mercy".

Now compound it with the fact that in electric mode this car with active noise cancellation is darn near the quietest thing anyone has EVER driven. It's easy to get used to that. Then the engine kicks on and after warm-up it revs to 3,000 rpm. While you're traveling only 40 mph no less. This makes the engine quite noticeable. And that bothers some people. They report "angry bees."

Lets compound it further and acknowledge that most Clarity purchasers bought this car for relatively short trips, with most striving for as much EV driving as possible, and there are few road-trip discussions here and few long-ride vacations taken. So if you have a 50 mile range, rarely exceed it, and now drive it 60 miles one day, you have 50 miles of usual silence and a comparative 10 miles of "wierdness" and "angry bees" -- which you would rapidly learn and understand more if you just kept driving for another 200 miles. Many owners would benefit from allowing the programming to go through all of its cycles periodically so they can learn more about the car...instead of ALWAYS trying to drive it like a BEV. This is NOT a BEV -- it's a PHEV. Running the engine is good and smart...an engine that never starts is an engine that's dying a slow death.

Anyway, on longer trips I assure you the car settles in eventually -- the first 10 to 15 minutes or so of ICE coming on can be a bit odd as the engine warms up, you still lose more EV range, then the engine later starts revving to replace that EV range it lost during that warm-up process. It later does settle in to a nice even RPM after the computer figures out what load it's really taking on with this particular trip...unless of course you keep pushing buttons and resetting things...

My biggest point is it's just different. Not broken. And whether people "like" it or not is very subjective so there's no point in even discussing it -- if you don't "like" it, by all means do whatever you "like..." Push buttons till you're happy, or sell the car, or whatever.

And as a disclaimer ALL of my numbers above are fabricated/estimated/assumed out of my own head and from my own experience of driving (and tuning and rebuilding) many 4 cylinder cars aggressively and knowing what they sound like...and having repaired/tuned/rebuilt multiple gasoline powered electric generators...I really do think my numbers are relatively close to reality.

Enough yammering -- just trying to explain my train of thought. Maybe this clarified or maybe it confused...

Bravo!!!
You nailed it.
Better Efficiency VS. Quieter Ride
There is always a sacrifice.

Off topic somewhat. I am in the process of adding sound insulation in the hood, doors, trunk, firewall. Budgeting $200 for materials only. If I hear the difference, I will attempt the roof and floor.

 

[MPower]

Better Efficiency VS. Quieter Ride

There is another alternative--lower speed. I have found that reducing the speed to just below 70 mph seems to asure a quieter ride.

 

[KClark]

I think MrFixit may have something. I think speeds above 70 mph are a significant factor. It seems to me that a number of threads have contained references to unsatisfactory/excessive engine noise at high speed conditions.

I rarely go over 70 mph, but my only experience of angry bees was doing 72 mph going up hill in HV with a half full battery, temperature in the high 20Fs. The minute i reduced my speed to 67, the noise stopped even though all the other conditions remained the same.

I agree about the speed. Which is why I don't consider the Clarity an ideal highway cruiser for the western US where there are miles and miles of wide open road with high speed limits. Parts of I-15 in UT have an 80mph speed limit, most other non urban parts of I-15 have a 75mph speed limit. Most of that is two lanes and even the semis are pushing that speed limit. Drive much slower than 75 and deal with angry drivers behind you. I tried setting ACC at 80 and it seemed like a little too much, 75 was OK but noisy. When I get out onto the open highway I want to relax, it wasn't a very relaxing ride.