Low speed engine noise

Try test driving in HV mode with at least 40% battery, in local stop an go traffic. From experience, in some Claritys, the revving turns on not so much on the highway but when you're starting from a stop light/sign and accelerating to like 30mph. Once the power meter goes above blue, the car should be operating via the engine and out of EV mode which is where any noises will come out.

 

Maybe ICE is run at higher rpm for highest efficiency when charging the battery?

 

I am very interested in the Clarity plug-in hybrid, but I am concerned about this potential low-speed gas engine noise issue. Are there any other comments from new owners who have not shared their experiences on this forum on this issue?

 

Our Clarity is extremely quiet under almost all conditions.

We've heard the angry bees once for about two minutes on the highway at 75mph with over 50% charge. On that same drive we climbed a mountain road at 65mph during which the ICE revved high but not the angry bees sound. This was a one time event. We now have about 11,000 miles on the car.

Other than that one time I simply haven't heard the engine.

 

My experience with my Clarity has also been tranquil silence. The entire pattern of ICE activation is still being sorted out but I believe you can minimize it by:

1) Understanding that high momentary power draws, such as to go uphill, can be provided by battery (silent), engine supplemented by battery (pretty quiet), or engine unassisted/barely assisted by battery (high rev and noise). This last occurs when battery is low. Solution: enter hilly areas with adequate charge.

2) Understanding that HV and HV Charge have periods of highway-speed-type engine revs, regardless of car speed, because that is an efficient way to run the engine (cycles of high efficiency alternating with being off). These cycles are pretty imperceptible at high car speeds (wind noise masks it, plus it seems normal based on all our ICE experience at highway speeds). These HV cycles are however more perceptible, weird and annoying at low speeds. Solution: run HV (if you need it to conserve battery to reach destination or for upcoming hills) mostly at highway speeds. Turn off for stop and go.

3). Even on flat ground, engine will race with acceleration if battery is dead (like #1). Solution: Again, leave some battery reserve for acceleration.

I won’t pretend to understand everything about the ICE but with this strategy, which involves very minor planning for long trips (to save some battery for later), my Clarity has been a quiet dream. Depends on your drive though.

 

My wife is pretty sensitive to the engine noise. This past week, after running out of battery, driving for 20 minutes on depleted mode, as we were pulling up to our destination she remarked, “oh, is the engine on?”. She hadn’t noticed it in 20 minutes of driving.

 

I have had depleted battery several times and find the engine’s short on/off cycle annoying. It’s fine when it runs continuously, but not otherwise.

I find leaving the car in auto mode better at low speed rather than HV mode due to this noise issue and smoother blending of power. I haven’t tried sport mode, perhaps that will keep the engine on. I have also heard angry bees several times for short bursts, at this point the curiousity of this sound has not yet tuned to annoyance, but with time it likely will for me.

But the noise is certainly annoying, I am learning to live with it.

 

I drive months at a time without having the engine start. I have only made one road trip of 800 mile where I did not have access to a charger. My trip was at high altitude (almost always above 5000 feet and up to 6800 feet) and at speeds of 75 or 80 miles per hour. At those altitudes the small engine does not have the power with the clutch engaged to propel the car at those speeds even on flat ground. So I spent much of the trip with the engine revving at a high and noisy speed. During the trip the EV range slowly got smaller and I ended the trip with 17 miles of EV. The car did have plenty of power with the engine running that way but it was very annoying.
I do travel at 70 + miles per hour on the freeway in EV mode for short trips all the time and never have the engine run.

 

Found this thread and trying to get some clue.

Just got a brand new 2018 Clarity PHEV, drove under 200 miles. While the battery has 30 miles range in EV mode, high rev noise coming up when waiting at red light. I thought it was the car next to me but turn out it's the Clarity. I can hear it with windows up, music on, so it's farely loud. I turn off music/AC, it's still going on. Once the car start moving again, the noise is off.

I was driving in normal mode, not HV/Sport/Econ.

Next time I hear this I will put on Brake Hold and record it on video.

Kinda disappointed at how noisy it is, especially I picked the car and I have to explain it to my wife. o_o

 

Just keep driving it. It will be quiet.

 

Same behavior as with the Accord Hybrid because it has, wait for it.... the same powertrain.
Actually, the Clarity has the Accord's Gen II powertrain (Gen III doesn't have rare earth magnets)
The design is engineered to divorce the engine from the drivetrain and the result is engine loads and speeds that are not proportionate to current driving.
Example - silence at 45 MPH or 2000RPM in HomeDepot parking lot.
The powertrain uses the engine to charge the battery at optimal load/RPM exclusively or turn it off.
This design is optimal for engine efficiency (MPG) by keeping the engine on full load in the sweet spot, but will probably sound a little odd to most people.
The upside of the Clarity PHEV is that the high voltage battery can be used for EV mode in low speed settings where HV behavior might be more noticeable.
On the highway, most people can't even tell if the engine is running or not.
Odd sounding or not, I think the Accord Hybrid and Clarity PHEV represent some of the best engineered hardware out there.

 

Hmm. Going on a road trip tomorrow so hopefully no angry bees here! Our first test drive was on a clarity with no battery of course. You could hear the engine a little but not bothersome. Of course I’m coming from a loud and ancient car so that may also explain a difference...

 

I roll the windows down and listen to the engine while driving around town if I am in HV mode.
I am almost always in EV mode in town, so I hardly ever get to hear the engine.

 

Finally heArd the bees on my last half mile of a 300 mile trip at low speeds/up hill coming home. Engine was also a little loud accelerating up hill but tolerable. The loud sound when you are driving at 20 is a little unnerving. Still quite happy given I expect most of my driving to be EV and it pretty quite for most of the hv driving so far as well.

 

Please help us understand the conditions.
What was your battery charge at? Or how many bars we’re showing when this happened? How steep was the hill? We’re you already in HV mode or had you switched to EV and it switched to HV automatically due to battery depletion?
Thanks.

 

I bought my Clarity in late Feb and was getting approx 40 miles per charge. I had to drive about 100 miles the next week on a trip in 30 degree weather. I didn't know anything about HV vs EV and I always drove in Econ mode. I knew I would run out of battery but didn't have any other choice. The trip there involved 2 large hills with valleys in between. Hills were about 1500 ft each. So I ran out of battery half way there and heard regular bees on the highway. When I hit the first hill, I heard the angry bees. My son in the passenger seat said it was revving too high and I did consider that the engine might explode. My husband works on cars and when we met up with him, he assured me that it was not revving too high and would not explode. On the way home, we heard angry bees on both hills and regular bees the rest of the way.

I haven't heard the sound since then because I have not driven without battery since except for a mile or two to the nearest free charger. If I take a trip over 40 miles now, I know to use HV etc because I found this forum and have done research. When I mention the angry bees in front of my husband, he says I am exaggerating because the car is so quiet and that I have forgotten what other cars sound like but I remember the angry bees and it is not normal sounding. I almost wonder if I was breaking the engine in because it was so new.

 

First time in 5000 miles had the bees. Conditions:

Econ HV Mode
40 mile HV range on Battery
I-25 Raton Pass Colorado/New Mexico (southbound) Up to a 6% Grade and 1600 foot elevation gain
Speed 65-70 mph - temperature about 70 degrees
Mostly on cruise control and never hit the pedal indent.

Didn't bother me one bit. It appears that the ICE has 3 rev positions: Low , Medium and High.

 

I've driven the Clarity for 2 months, and it is the quietest vehicle that I have driven. I'm coming from an Acura TSX. I've never had the ICE engine go on, except for when I want it to go on. I go to HV mode on the highway to ensure I have enough battery power to go up steep hills. I use HV mode climbing hills. I never hear the ICE engine in HV mode. I can't distinguish the ICE engine sound from regular road noise.

 

When I bought my Clarity, the battery was of course down to two bars off the showroom floor. Having already studied up on the car, I knew that the car would basicallly be in HV mode for the trip home. Watching the fuel consumption display I could easily see when the ICE turned on, and if I listened I could hear it but it was subdued. When I hit surface streets though, the sound was far more noticable.

A few days later, I had a lot of running around to do, and I when I left the house, I ran the car in HV mode the whole time.

In HV mode, the ICE would come on, but the engine speed was so low that it was not at all intrusive.

The best thing is that in a trip that I would only get about 50 MPG in the Prius, I was able to get 65MPG in the Clarity in HV mode!!!! I was pretty amazed by that!

Now this is my third Hybrid and my first was the original insight, and I consider myself to be a bit of a hypermiler. I am getting close to 60 miles on a battery charge, but I was thrilled to see how well I could do in HV mode running around town (no stop and go traffic). With the battery half charged, the engine was not intrusive on the highway and barely audible around town. Only a glimps of the MPG indicator would be a sure fire tip that the ICE was running.

 

Battery was long depleted to 2 bars. Hill was maybe 5%? Not sure but something reasonably bikable not too steep.