Low speed engine noise

I also have the engine rev at slow speeds when the battery is drained. I can also hear it at highway speeds, but the road noise drowns out most of the rev noise. Since, 90% of my driving is within EV range and the ICE rarely comes on, it's not a problem for me. I have tested it enough to know that it would be difficult to live with on a daily basis.
The 2 white notches are always on when the EV range goes to 0, so that seems to be when the ICE comes on.
Most people on this forum say that they cannot hear the ICE, but that is not the case for me. It always seems loud. Can't decide if there is something wrong with my Clarity, or I have really good hearing or am just spoiled by the quieter electric motor.

 

I am not experienceing an overly loud engine rev. Just a low engine sound like it’s doing maybe 2,000 rpm. It’s hardly noticeable.
I have noticed that if I let the battery deplete to zero EV range/2 bars, the ICE will come on a lot more frequently and with higher rpm especially on hills or when I accelerate briskly. I have found it’s better to switch to HV mode on hwy trips before the battery is fully depleted. When I do the switch to HV at about half or quarter battery, the ICE seems much more docile and quieter. I suspect at full battery depletion the algorithm has less flexibility in selecting and switching power inputs. Try that and see if it makes a difference in rpm/sound.

 

A video might be helpful. The engine is barely audible cruising down the highway, but occasionally will make noise if it revs up.

If you have problems with how it runs in that mode, if you regularly run it down to 0 mile range, maybe use HV mode before the battery is depleted. That will hold some charge in the battery so when you go up a hill or something it will use the battery instead of making the engine rev high RPM.

For example, pretend you have a 50 mile commute, 40 miles highway, and 10 miles slower speed at the end. Say you usually run out of range about the end of the highway section. Instead, try putting the car in HV mode when the battery is about half dead, so when you get to your low speed section you will be on EV only in that section (switch back to Econ/Normal/Sport by turning off HV mode).

When the battery is dead the car will mostly use CVT mode at lower speeds, which causes the engine to rev wildly depending on what you are doing. I find the engine less intrusive at highway speeds, so prefer to save EV for around town.

 

How far is your normal commute? I agree about the drone of the ICE at low speeds, which is why the goal is to minimize the ICE powering on during local driving.

 

I know the noise the OP is talking about. It's what you get when you try to push a two-ton vehicle using an engine built to power a Honda Fit. And it's the same noise you hear if you double click the HV mode button (where ICE is used to charge battery up to 60%) There was a thread awhile back that had a good link to information about why the engine ramps up like it does - particularly after being under load - or when charging the battery.

 

If you switch to HV mode for some of your commute when your speed is over 45 mph, the clutch will connect the engine directly to the wheels and the engine won't race. Under 45 mph (it might be 43), the clutch disconnects and the engine is generating electricity to power the vehicle and runs at a fairly high speed.
Since the temperature where I live has been in the high 50s and low 60s so I don't need to run the heater, my EV mode has been giving me 56+ miles. I was getting about 40 when I needed to run the heater.

 

After reading about others experiences, to minimize engine noise and drive efficiently (the two seem to go together) I use these guidelines:

1) if I can do the whole trip on electric, stay in normal mode.
2) otherwise use HV for freeways and save battery for street driving and heavy freeway traffic.

The only annoying part about 2) is I want to fully use up my battery so I have to time turning off HV on the return trip.

 

So I test drove a Clarity today with low battery power and driving on city streets was unbearable. It felt like the car was stuck in 1st gear - is this the low speed engine noise everyone is talking about? If so, this really bums me out because it was really distracting. I was under the impression this thing was quiet and there was none of that to be had.

 

The car is quiet if you follow the advice by Bpratt above as be mindful of how you are using your battery power. The battery is best for slower speeds but is less efficient than the ICE at higher speeds. The vehicle is programmed to use the most efficient means of propelling the vehicle to get the best milage possible thanks to the parallel/series hybrid system in the HV mode. If you can do the whole trip electric and have charging capabilities then go all electric but if not, conserve some battery power so that the battery can work along with the ICE since the engine is an Atkins style which has superior milage but inferior performance the the Otto style engines in all other non-hybrid ICE cars.

See these links to a paper and presentation by Honda in the post by ab13 https://insideevsforum.com/community/index.php?threads/honda-clarity-power-split.418/#post-3740. Awesome information if you take the time to study it!

 

I don't know if this is any help but I've never heard the engine noise your talking about.

 

I haven’t either. With HV battery fully depleted, I’ve only just barely heard the engine when accelerating moderately or going up hill and even then it was not highly reving and not very loud. On the hwy it cycled on and off frequently, changing modes. It was a little louder than HV mode with the battery at half capacity but not by much.

 

My experience is that you only hear this when you run on EV all the way down to the last two bars and the ICE first comes on. The car then goes into a short battery conditioning mode for 1-2 minutes then downs in RPMs down to a noise level close to EV level from that point on. This is normal and expected if you run on EV to ICE. As others point out, it can be avoided by running in hybrid mode prior to depleting the battery. There are times in EV if you put the peddle to the floor on a hill that you can make the ICE kick in at a high RPM, but that’s not normal driving. I live in a mountainous area and drive a 36 mile commute everyday 30-55mph on pure EV without the ICE ever coming on. I have been doing this for almost 4 months now. Different from you, I continue to fall more in love with the car with its consistent EV performance even in freezing weather. I’d never have to run the ICE except for when we go on a road trip beyond the 40-50 mile EV range. We’ve done that a half dozen times now and I think we are on our fourth tank of gas.


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The Accord hybrid (soon available) and CRV hybrid (Europe only for now) use the same drive system as the Clarity but with two important differences. The first is a much smaller battery so they can't do all electric for very long. Because of that, they depend on the ICE most of the time. Even though both are lighter than the Clarity, they carry significantly more powerful 2.0 liter engines to generate sufficient electrical power at lower revs. For the Clarity, Honda realized that most buyers will be staying in EV mode most of the time so installing a 2.0 liter engine will add unnecessary weight, which will reduce EV range and HV gas mileage. I found the 1.5 liter to be smooth on a 1200 road trip that we took in mostly HV mode while providing sufficient power. The ICE has a red line of at least 6,000 and if you've ever owned a stick shift Honda VTEC (designed to rev high regularly), you'll know that your Clarity ICE is staying well below the red line. Besides, it's computer controlled so you should relax and ignore the engine sounds.

 

The dealers need to understand that the car must be charged. People who test drive the car when it has never been plugged in will be very disappointed. The performance suffers and the noise is unpleasant. It’s not a great intro to the joy of PHEV ownership.

 

I think this sound is actually different depending on the car. I had a loaner Clarity which never revved, even on depleted battery, but the car I actually bought does. Even the salesman noticed the difference. I don't know why, but it does explain why some of you have heard it and others have not.

 

The system may have some sort of engine break in period algorithm. It may be doing more varied RPM, putting in a high RPM limit (especially when not up to temp), and enforcing a minimum on time to make sure the oil gets up to temperature and properly coats the engine parts.

 

So they can deceive the customer into thinking they will be buying a quiet car? It seems like there are enough reports of this to show that the car has a design or build problem. I never put my 2014 Volt into hold mode. I let it use up the battery charge first and then go into charge sustaining mode. I tried playing with hold mode when I first got it, using the ICE on the highway and the battery around town, but I couldn't see an improvement in efficiency. I know that theoretically it might be more efficient to do that, but I think the real life gains are tiny. And if I misjudge and pull into my garage with any charge left on the battery, I KNOW that I just wasted some gas and money.

Yes the Volt runs the engine at higher RPMs sometimes, especially when going up a hill, but it is comparable to a fairly quiet ICE car, not a luxury car certainly, but far from an econobox. One of the selling points of the Clarity frequently mentioned is how luxurious it fells. I certainly think it feels more luxurious than my Volt. Probably the main reason I am considering it is the seating is more comfortable and convenient (power seats). If I buy it and it sounds like angry bees or an econobox unless I manage the battery charge level carefully, I will be very disappointed.

Hopefully Honda can fix this problem with a software update. It seems like they could increase the battery buffer just a little bit and program the engine to run at lower RPM for a bit longer to replenish the battery. Hopefully that wouldn't decrease the EV range substantially.

 

I’ve got about 800 miles in EV and 100 miles in HV and have never heard the angry bees’ sound ever. So my particular Clarity is close to a luxury car.
But some posters have so it exists in some cars but not others. Have no idea why.