Engine engaged clutch slip and smell?

Discussion in 'Clarity' started by chris5168, Oct 20, 2018.

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  1. chris5168

    chris5168 Member

    Today with ‘2-bar’ (depleted) battery, under somewhat hard acceleration between stops signs, heard and felt like the clutch slipping. Then when I stopped and garage parked, I could smell the distinctive clutch smell.

    Anyone else have this experience? This could be an expensive wear-and-tear item to replace if driving often on gas only.
    holyfork likes this.
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  3. ryd994

    ryd994 Active Member

    The clutch doesn't engage until ~40mph at least. Just my personal feeling
    Gearhead and insightman like this.
  4. jorgie393

    jorgie393 Well-Known Member

    The Clarity almost never uses a mechanical clutch, even when the gas engine is on. The engine usually drives a generator. Only at highway speeds is there an actual mechanical clutch. Doesn’t sound like this applies here.

    Fron my own experiences with failing clutches, the symptom usually is engine revs way, way above the car’s travel speed—decoupling of the engine revs and speed. But this is commin with the Clarity, especially when you ask the small engine to generate enough electricity to rapidly accelerate a 4000 lb car without help from the depleted battery.

    I speculate that what you are experiencing is described by others as the well known “angry bees”, see many other posts. I remember this behavior when on a test drive with 2 bars. Best avoided by preemptively engaging HV mode to keep battery from running down.

    As for the smell? I am not sure but I don’t think it’s the clutch if this was happening at city traffic speeds.
  5. Atkinson

    Atkinson Active Member

    As stated above, the clutch is not used below 45 MPH and even then only under moderate throttle.
    You are probably smelling oil burning off the hot parts of the engine exterior and exhaust.
    This happens with all cars the first time the engine is under full load.
    There is no transmission to slip on the Clarity.
    Since the engine and final drive axle are not connected under most conditions, you should not expect the engine speed to be in any way related to how fast the car is moving.
    insightman and jdonalds like this.
  6. PHEV Newbie

    PHEV Newbie Well-Known Member

    I agree that the clutch does not engage at those speeds, by design. I wonder if the burning smell is simply the burning off of residual oil and coatings on the gasoline engine. Just about every brand new ICE car I've owned had a few days of a burning smell after I take delivery. One time I actually brought it back to the dealer and they explained what it is and yes, it always goes away. Hopefully, that's all it is for you too.
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  8. Yeah, it sounds like the engine was racing to keep up with the low battery charge. The engine does rev up high and the fact you are not driving fast allows the fumes of the hot engine to accumulate giving you the smell. Like it has been mentioned, keep the car in HV mode if you are going to drive it with a low battery. If the battery over depleted in some situations, it will over compensate to try to keep the charge.
  9. Robert_Alabama

    Robert_Alabama Well-Known Member

    My 2012 Volt had a bad burned rubber smell for the first 2-3 years whenever I ran the ICE even a little bit. It finally calmed down, but the car is over 5 years old now. That said, burned clutch or burned brake smell is distinctively different. If the symptoms keep up, I'd take it to the dealer (and I'm not one to take a car to the dealer for much). Also many Volt owners were reporting that smell. I haven't seen any of the Clarity posts talking about this, but I've been prone to miss posts, so take that for what it's worth.
  10. chris5168

    chris5168 Member

    Thanks for your feedback. I’m going to see if I can duplicate but here is more details. Car was traveling faster than 45 and engine revs matched that of the accelerator pedal, not angry bees sound. Identical to driving a car I had in high school with a bad clutch, gingerly you could get it to move, but smashing on it would slip.

    So the smell, pretty certain it was clutch smell, but will see if I can duplicate again as the oil smell makes sense as well.

    It didn’t help that I was also doing comparisons with sport mode prior, so pushed beyond what would be normal driving. The engine is the drawback to this car, wish the 89 mile pure electric was available for purchase.
  11. chris5168

    chris5168 Member

    What does your Clarity in Sport mode do when you floor it from a stop to about 70?

    Mine speedy start, engine on at 40 mph, revs match accelerator but due to what I think is clutch slipping, car doesn’t gain speed as it should. If I drive it reasonably fast, it’s fine.
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  13. leop

    leop Active Member

    Please take this explanation with caution as this comes from reading various Honda published papers and popular articles and then drawing some conclusions. I believe that a "wet" clutch connects the engine directly to the single speed transmission in the "direct engine drive" mode that is used at cruise above about 45 mph when the HV mode is selected. A "wet" clutch runs in the transmission fluid (like typical clutches in the usual automatic transmissions or the manual, multi-plate clutch in many motorcycle transmissions). The HV mode is in "parallel" when the engine clutch is engaged and the engine is directly connected to the transmission. The single speed transmission is geared fairly high similar to the over-drive gearing in a typical transmission. In this mode some additional torque can be supplied by the electric traction motor when required such as for climbing hills.

    When there is a high torque demand, even over 45 mph, the clutch disengages and the system goes into a "series" HV mode where the engine mounted generator supplies the engine load and the traction motor gets power from both the battery and the generator. This "series" mode allows the engine to operate in a higher (and more powerful) rpm range than if the engine was directly connected to the single speed (over-drive) transmission. This mode often results in the "angry bees" sound as the engine is operating in a higher rpm range with more power output as compared to the rpm and power of the engine when directly connected to the transmission.

    The Hybrid Accord has a similar power system but has a larger, more powerful engine than the Clarity. Thus, the control settings are different and the Accord engine can stay directly connected more of the time when there are higher torque demands. The control settings depend on the available engine power, the maximum power that can be drawn from the battery, and the maximum power that can be produced by the traction motor. Please note that the maximum power (amperage) that can be drawn from the battery is a major limit on torque. For example, in the case of a Tesla that can have the "ludicrous" mode, the power cables from the battery are upgraded to carry more amperage. Even so, the time that the maximum current can be drawn is limited by the ability to cool the battery and electrical system during high current flows. The Honda system is fairly conservation in torque output, current draw from the battery, and current input to the traction motor. Along with the Clarity's active battery and inverter liquid cooling systems, this makes for a more reliable power system.
    Vezz66 and KentuckyKen like this.
  14. ryd994

    ryd994 Active Member

    Do you have a reference about wet clutch on clarity?
  15. leop

    leop Active Member

    Here is a description for the Accord Hybrid which uses the same i-MMD type system as the Clarity (hence, my "I believe" comment):


    The above also has picture of the multi-plate wet clutch from a cut-a-way view of a Honda display engine-transmission for the Accord. There are other references to the i-MMD system (and wet clutch) in the Accord Hybrid in the popular literature.
  16. ryd994

    ryd994 Active Member

    Wow that page has a ton of information
  17. insightman

    insightman Well-Known Member Subscriber

    Let's hope they find the Clarity worth the same detailed internal examination!
  18. I bought my Clarity about 4 days ago and have had no use for the ICE, however, I have decided to drive in HV mode and use HV CHARGE mode to burn all the fuel in the tank (it sat at the dealership for over 10 months first of all) in order to refill with “fresh” gas... the primary reason for this for me is that I want to refill with non-ethanol fuel since we will rarely tap into the ICE... the non-ethonal (IMO) will be much more stable

    The point of this post is that I ran my ICE for an extended time today (more than an hour) and notice the same smell you describe, it is definitely “beak in” smell of oils burning off and nothing to be concerned about, though it does smell awful
  19. ryd994

    ryd994 Active Member

    I smelt something awful when I was drving among the hills, up and down a lot. Battery was dead, because the road was mostly upwards. The engine was definitely under heavy load.
  20. L.L.

    L.L. New Member

    I had a similar experience about two months ago during our trip to Colorado. We were going uphill through the Rockies with about 17 miles of EV range left in HV mode. The smell was very apparent as the motor sounded like it was pegged at redline while the speedometer was stuck at 45mph and power meter would not go past the 1 o'clock position. Any guesses as to what might have been the issue?
  21. AlAl

    AlAl Active Member

    I was clearing off the frozen snow from my car today and ran the engine on HV charge mode to defrost the rest of the car. Was getting that distinct clutch burning smell after a minute of run-time.
    Engine sounded like it was hovering around 1100 rpm range for the entire 15 minutes; not pegged at all

    ICE has about 1k miles of operation on it. Should I be alarmed?
  22. ab13

    ab13 Active Member

    This may be that engine smell when oils and stuff burn off on a new engine.
  23. Gearhead

    Gearhead Member

    Sure you didn't burn some tire? Happened to me last week and only under slightly more than usual moderate acceleration. I have the OE Michelins with temps in the 30's and I suspect the compound is very stiff and consequently slippery in the cold.

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