Vibration on take off from stop/roll? Is this normal?

[Buying07TCH]

I am considering buying a used 2007 TCH. It has low miles and full remaining factory warranty. I took it for a test drive and loved it, but the only question is when acceleration slowly, from a stop or a roll, the car has a mild vibration or shimmy. It seems like the transmission is trying to link up or the electric and gas systems are coordinating. I have never driven any Toyota Hybrid, let alone a Camry hybrid, and was wondering if this is normal and if any owners out there are nice enough to tell me if they have ever encountered it if it is not normal.
I spoke to someone at Don McGill Toyota in houston, Tx and they told me that a slight hesitation or vibration from a stop is normal for the hybrid as the system is trying to be efficient.
Can any owner give me their take?
- Mark

[Tideland Prius]

lol... no. It should be smooth as you accelerate. You *might* feel something when the engine turns on or shut down but that's about it. I would pay attention to the screen or the mpg meter and see when the engine comes on and whether that coincides with the vibration. If not, then I'd move onto another TCH.


Alternatively, test drive another TCH.

[ekpolk]

My 09 demonstrates a bit of what I think you're describing. I've owned two HSD cars now (see sig below). In most respects, the TCH is more refined and smoother than the Prius, which is only to be expected I suppose, for any number of predictable reasons. But I seem to get more "rumble" from the TCH than the Prius. Go figure. That said, remember that all of the HSD cars are different animals. They're simpler than conventional cars in some respects (no starters to fail, no alternator, no PS pump, etc.) and more complex in other ways (the hybrid hardware would be the main thing...). The HSD cars do give off some rumbles and noises that you'll never feel or hear in a conventional car -- they're just part of the package.

One thing you should know, and it may be part of what you're describing, goes back to the fact that the HSD cars have no starter. They rely upon MG1 (the smaller of the two motor-generators) to start the ICE (gas engine). One very smart thing the cars do is that the electric side will spin the gas engine up to roughly 1,000 rpms before the ECU sends in fuel or spark. This allows the ICE to develop adequate oil pressure before it is subjected to running loads. As you become proficient in driving the car, you can use the faint "rumble" of the ICE spooling up as a cue to back off the gas pedal to keep the car in an electric-only "stealth" run for even longer. This "rumble" may be what you're feeling.

Another thought -- the gas and electric systems never really have to "coordinate". In fact, they're never, ever truly disconnected from the drive wheels. The PSD (power split device) is an amazingly simple device (a planetary gear set, google PSD and Prius if you'd like a full explanation). Once you've studied the workings of the PSD, you will see the answer to the riddle of how the car can never declutch, and yet the ICE can idle happily with the car at a dead stop (hint: outer ring of PSD will be stopped since it's geared to the wheels, ICE will turn the middle ring, and the planet gears will turn the center shaft, connected to MG1, which will charge the battery).

I'll just stop now...