New car, whirring sound when accelerating from low speed

Discussion in 'Clarity' started by DC2, Apr 14, 2018 at 3:52 PM.

  1. DC2

    DC2 New Member


    I just recently purchased a 2018 plug-in Clarity yesterday. On the drive home (in I presume normal EV mode with no buttons pressed), I noticed that there's a whirring engine/generator when I step on the accelerator between 25% to 50% speed going from 25 to 40 mph (shown in orange in the picture). Is this normal behavior for the clarity?

    Attached Files:

  2. DC2

    DC2 New Member

    Last edited: Apr 14, 2018 at 7:24 PM
  3. DC2

    DC2 New Member

  4. KentuckyKen

    KentuckyKen Active Member

    That is indeed the trigger. The ICE is trying to put some charge in your depleted (2 bars on guage is full useful capacity depleted) battery so that it can switch between all of its power modes and give you the best mpg. I have found that I can avoid the high reving/angry bees by manually selecting HV mode (not HV charge) before full usable battery depletion at 2 bars remaining. Then I only get a barely noticeable “fast idle” kind of sound unless I hit a steep hill or call for maximum acceleration.
    Sounds like your car is acting normally. Try charging the battery and I bet your “problem” will go away. Please try and post what happens. We need all the data points we can get to figure the Clarity out.

    Other posts have mentioned that the dealers don’t understand this and will give test drives with the battery depleted and the high reving/angry bees will make potential buyers think it’s a noisy car when almost always it’s the quietest car out there.
  5. barnesgj

    barnesgj Active Member

    I concur with KentuckyKen. Only occurs when the battery is depleted. I had an appointment to get it looked at, too, but canceled it after the input from this forum. Am not ready to have the mechanics poking around under my hood.
  6. DC2

    DC2 New Member

    I was able to take a video on my way to charging. Here it is on Google Drive:
    The sound becomes very apparent around 16 seconds in. ALthough I was driving under 30 mph, it sounds like the engine was running super hard. This was running with HV mode on I believe, but the same sound occurs without HV mode.

    After charging ~1h20min to ~60/70%, the car ran super quiet and was normal.
  7. kkiran

    kkiran Member

    I see random engine revs but it only happens when I like some fun on the road!

    It is so eerily quiet for a Honda, never experienced this before (Tesla is an exception). Can’t wait for enhancements in the next generations of the Clarity.

    Sent from my iPhone using Inside EVs
  8. css28

    css28 Member

    Once your battery is down like that the car operates the same as in HV mode, as you discovered.
    For the Chevy Volt this is described as Charge Sustainment (CS) mode.
  9. DC2

    DC2 New Member

    Is it supposed to be that loud in HV mode? I was around 33% battery this morning and when I turned on HV, a lot of reving occured. Is there a way to switch to only gas powered?
  10. css28

    css28 Member

    I think you'll find that the car initially "falls behind" in battery charge while the engine is initially warming up then races to catch up if you switch over at highway speed. Try pushing the button a minute or two before you get on the highway so that the engine can warm up a little before it has to get to work.
    Let us know if that helps.
    Johnhaydev and KentuckyKen like this.
  11. DC2

    DC2 New Member

    Hmmm, I've been switching to HV on local roads so I don't think it's highway speed's that's causing the revving. After service today, the technicians mentioned that it's normal.

    I'm going to try this tomorrow and place the Clarity into HV Charge Mode (29s in the youtube video) and turn EV off just for instances where my power is low but I want to drive without the revving sound.

  12. DC2

    DC2 New Member

    Drove local, pushed car into HV charge mode at about 35% power. There was a different hum from the engine and a slightly different by similar revving/rumbling from the engine. I guess these engine sounds are just from the EV charging. Is there a way to go into a no charge, gas-only mode?
  13. css28

    css28 Member

    That's what short press HV mode is (in a hybrid sort of way).
  14. DC2

    DC2 New Member

    It seems that short press HV is still charging when power is low. Given that I don't have a charger at home, when I'm low on power (~33%) revving occurs:
    1. When I'm in EV mode
    2. When I'm in HV mode
    3. When I'm in HV Charge Mode
    4. When I'm in sport mode
  15. css28

    css28 Member

    Now I understand. Use HV charge mode to get the battery up a bit (say, 50% or so) then HV mode should be less noisy when you use it.
    Purely gas mode isn't practical because it's a small Atkinson cycle engine and would be really gutless without the battery to help at times.
    Johnhaydev and loomis2 like this.

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