How does this mode work?

[Shaft]

Scenario: It's real cold outside. My Volt is fully charged and I've conditioned at 220V. But it's so cold that the ICE comes on anyway and stays on for about 10 minutes.

Question: Is this mode (i.e. ICE running for 10 minutes despite the car being conditioned and fully charged) just like extended range mode after the battery is depleted? Or is the control algorithm that blends battery and ICE operation in this scenario different in some way from extended range mode?

[ki8as]

How do you have your heater set? If on comfort mode it may be that the ice is coming on to augment the heater.

[Rich Remund]

Maybe we can get an engineer that knows, tell us a little more about the algorithm. I'm sure they are starting the engine more often in the early cars so as to keep the battery warm and extend the range, this may be tweeked in the latter cars. The objective, I'm sure is overall MPG. This may effect the short drive commuters as they could utilize the battery more to warm itself and the cabin, while affecting the overall range, even though they only need 10-15 mile total range out of the change. I know from experience, I have seen over 30 miles EV with temps in the teens, with no engine starts by keeping the climate control off and just turning it on just to defog the windscreen, then off again. This is a mix of local back roads at 45-50 and hwy at 60-65. My Garage is about 40-50 degrees and I precondition with 110v about 20-30 minutes, before heading out.

We need the charging stations now!!

[Kup]

Maybe we can get an engineer that knows, tell us a little more about the algorithm. I'm sure they are starting the engine more often in the early cars so as to keep the battery warm and extend the range, this may be tweeked in the latter cars. The objective, I'm sure is overall MPG. This may effect the short drive commuters as they could utilize the battery more to warm itself and the cabin, while affecting the overall range, even though they only need 10-15 mile total range out of the change. I know from experience, I have seen over 30 miles EV with temps in the teens, with no engine starts by keeping the climate control off and just turning it on just to defog the windscreen, then off again. This is a mix of local back roads at 45-50 and hwy at 60-65. My Garage is about 40-50 degrees and I precondition with 110v about 20-30 minutes, before heading out.

We need the charging stations now!!

Rich, have you tried preconditioning for 5 to 10 minutes instead of 20 to 30 minutes? I'm in the DC area and I'm guessing my garage is about the same 40 to 50 degrees but I would not have expected needing to precondition for that long. I'm guessing I have 4 to 5 weeks until I get mine but I'm just a little surprised that it would take that long to get the cabin up to 70-ish.

[DonC]

There are a number of threads about this. You probably want to do a search.

The issue is the temperature of the battery. Because neither 120v or 240v provides sufficient power to heat the pack, if you've requested a remote start the engine may come on to provide that power. Most people have reported that the engine runs more like three minutes than ten. If you've started driving then the engine will come on until the pack reaches its operating temperature of 32F. Obviously the lower the temperature the longer the engine will have to run, and the engine will come on if the temperature of the pack falls below its minimum operating temperature during the drive. In this sense it's very similar to what happens with a Prius, where the engine has to come on to warm the catalytic converter.

[Shaft]

DonC, I agree with what you say, but my question is deeper, and I do not think the answer has been written anywhere. In situations like I describe, where the battery is fully charged and the ICE comes on because of the need for heat, how does the control algorithm supply power to the wheels under different conditions? For example:
-At low speeds, is the ICE supplying the average power needs of the traction motor like it does in extended range mode, or will the fully charged battery supply the average power needs of the traction motor?
-At high speeds, will the ICE supply torque to the ring gear like it will in extended range mode? Or will it just sip enough gas to supply the required heat?

[DonC]

Those are very good questions. Very interesting issues to which I have no answers. We know that given that the battery is fully charged, using the same algorithm as if the car were CS Mode wouldn't work. The simple though less efficient method would be to run the car as if it were in CD Mode and just treat the engine as a heater. You could of course, if the battery dropped to some lower SOC point, run in something like a revised Mountain Mode. Given that we're not talking about running the engine for long, and given how lazy I am, I'd probably propel the car from the battery as if the car were in CD Mode and just have the engine heat the pack and the cabin.

No idea though how GM addressed this interesting situation.

[Shaft]

I do not think a driver can tell. So this is a question for WOT.

[Rich Remund]

Rich, have you tried preconditioning for 5 to 10 minutes instead of 20 to 30 minutes? I'm in the DC area and I'm guessing my garage is about the same 40 to 50 degrees but I would not have expected needing to precondition for that long. I'm guessing I have 4 to 5 weeks until I get mine but I'm just a little surprised that it would take that long to get the cabin up to 70-ish.

The engine doesn't run during my precondition at that temp and the condition cycle only lasts for 10 minutes. The 20-30 minutes gives it an oportunity to recover a 5% depletion of the battery used during 10 minutes. I can tell you your cabin temp setting will have an effect on the engine starting. The system attempts to maintain a reservoir of warm coolant that is shared with the battery, I think...

I also notice that at times when the engine does run for temp the display shows battery power supplying the engine, at the same time. So Im sure the engine loads are optimized to allow the most effecient transfer of heat while using the kinetic energy supplied as well. Remeber in an ICE about 70%of the energy goes out the tail pipe as heat. Maybe it needs a small gas heater like the early aircooled VWs.. nah..

[Supe]

really hoping to get more updates on this one as a Canadian in Alberta -30 Celc some days is very Cold and wondering how much fuel it would burn or would it be able to maintain temp off the battery on the more extreme days.