The "Engine Running due to low temperature" has been discussed a fair amount. Some users have mentioned that when using COMFORT climate setting that it reduces the number of times that "Engine Running due to low temperature" happens and the ICE turns on. Others recently stated it did not have any affect. I normally use ECO so I tried COMFORT this morning.
In the past while in ECO and using the scangauge I've seen the ICE turn_back_on/ERDTLT on when the "WT" Water (engine) Temp drops down to 114F (45C). I've seen it vary in the ICE shut off when the WT goes up to 154F (67C) - 164F (73C).
Thought I would provide some empirical numbers with a statistical sampling of 2 <grin> using COMFORT/74/auto. The test was for 12 miles. Mainly 40 MPH driving hitting mostly of green lights. Also my test on the way home showed the same thing.[/edit]
Using a ScanGuage this a.m. while it was 13F (-10C) ambient temp out:
So does this mean that the 'exchange' stays open in COMFORT mode and the electric heat (COMFORT) is keeping the "WT" / ICE "warm". That is above the 114F (45C) lower threshold?!? I've seen that suggested by others.
- ICE came on after a couple minutes of leaving 55F garage and ran for 3 minutes (0.07gal) until "WT" water (engine) temp hit about 164F.
- I noticed in my other vehicles that the Scangauge IA (intake air temp) would be very close to the ambient/outside air temp on my displays (Ford Exped, Honda Civic) BUT in the Volt I saw the the IA remain in the mid 40Fs ... remember the ambient outside temp was 13F (-10C). Perhaps I'm misreading this or is the Volt shutting some intake flap to help keep the ICE temp from dropping too fast.
- "WT" dropped on my 12 mile trip to work to 123F (50C) and stayed there! Actually within a few miles of work I saw it go back up to 125F (51C) and 127F (52C) ... and the ICE was still OFF. In other words, I never saw it drop to 114F (45C) again where the ICE would turn back on. ... remember the ambient outside temp was 13F (-10C).
P.S. Testing is a little annoying because I think my ScanGuage shuts off based on 0 RPM after 30sec so I keep having to press the 'home' button letting monitor the WT water (engine) temp down to the 114F (45C). I'm surprised noone with a DASHDAQ or other have graphed this ERDTLT processing ... but perhaps all those supertechs are in the warm regions. [update]:this thread setting SETUP->FUEL->TYPE->HYBRID to avoid his.[/update]
[update] Going home test and fan speed setting impact:
I was able to get similar examples on the way home from work as the way to work (above example). Plus experimented with fan speed impact to lowering the engine temp (WT water temp). Lower fan speed slows down the cooling of engine temp ... as makes common sense.
A little experimenting 2/3s the way home showed if I used AUTO (4 level fan speed resulting) then the "WT" water (engine) temp went to around 125F but if I used 2 level fan speed manually then WT temp would go to 134F. I even saw it climb from 125F to 134F when I switched to 2 level fan speed from AUTO/4 when I did the switch with 2 miles left coming home.
KEY POINT: both fan speeds still let the engine temp stay above the ~114F threshold that would have done turned ICE on (ERDTLT).
[update] Using precond/remote_start to warm ICE for shorter ERDTLT initial runs:
Also see my post#12 of this same thread that shows how the ICE temp gets warmed up by doing precond/remote_start ... this should reduce the time/gas for the first ERDTLT running. [/update]