Do you ever feel some kind of transmission shift?

[Shaft]

I posed this question to Volt owner’s in another thread, but it got lost in other topics in that thread. So, I’ll ask again in the hope of getting more answers from Volt owners.

When the ICE is running in Charge Sustaining mode there are low and high speed modes of operation. At low speed, the ICE provides torque to the generator only. At high speed, various clutches open and close to redirect some of the ICE’s torque to the ring gear. The net result is lower traction motor speed and generally higher efficiency. And, of course, this also means that the Volt’s ICE is actively and mechanically contributing to the supply of torque to the Volt’s wheels (via clutches and gearing and other intermediary devices).

When this mode change occurs there are clutches opening and closing, both motors and the ICE changing speeds, and motors and ICEs being reconnected while potentially running at different speeds. I'm wondering if that feels like some kind of transmission shift.

My question to Volt owners is: What have you felt?

When I originally asked this question, I did get one interesting answer from RUSTY, which I’ll repost next.

Note: When I say "both" motors, I mean the traction motor and the motor/generator.

[Shaft]

Here’s Rusty’s answer to my question copied from another thread:

I've got over 5000 miles on my Volt, mostly CS mode on the highways/freeways. So mostly around 70 MPH. Until yesterday I had *never* been able to tell when it clutched in or out between those modes.

Yesterday on my way home from the CAB-fest I happened upon a pathology that *was* noticeable. But it was almost contrived and not likely to show up often. It would likely also be difficult to reproduce (without practice). And a lot of people probably wouldn't have even noticed it (a couple quick hesitations, about a sixth of a second apart).

[bjhorton2005]

I brought my Volt to West Virginia for the first time to visit family. In the mountains when requiring high amounts of power I am definitely noticing the "shift" but it's not bad an is comparable to that of the Prius I owned before.

P.S. Performing very well here in the mountains!

[rtmey2000]

I really don't have anywhere to charge at this time...so I use it CS mode all the time. I have not noticed this. If present...it is extremely subtle. I am now just getting aware of when the gas engine comes on..and you have to be looking for it to notice that.

I do notice others starting their cars all the time even around the block. It makes you notice that much more. And I definately notice the gear changes when I drive my wife's car...which I did not notice before.

[George S. Bower]

If we had the diagnostic tool we could monitor MG speed and clutch positions. I have maintained that, in order to maximize CS mode mileage, we need to run at the lowest speed possible in power split mode which should be 65-70 MPH.

Just wondering if any of you guys w/ cars have gotten on a fix on CS mode MPG at this condition. A comparison between 65 and 70 MPH MPG might reveal some interesting numbers.

[ClarksonCote]

I've noticed the transition from ICE back to battery (ICE running due to cold temperature) when it occurs at highway speeds, but it's nothing terrible.

[Slapshot28]

When the ICE is running in Charge Sustaining mode there are low and high speed modes of operation. [snip] When this mode change occurs there are clutches opening and closing, both motors and the ICE changing speeds, and motors and ICEs being reconnected while potentially running at different speeds. I'm wondering if that feels like some kind of transmission shift.

My question to Volt owners is: What have you felt?

When highway-driving in CS mode at around 70 mph, the speed where the ICE should mechanically join in (or drop out), I've tried earnestly to feel/hear any subtle transition. Any such transition eludes me, that's for sure. I don't sense anything at all. It's just smooth, period.

Chris

[supafrovolt]

Felt it a couple times though its pretty unobtrusive.

[Shaft]

Conclusion: It seems like Volt drivers do feel something, but infrequently with significantly less impact than an ICE with a regular transmission.