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Any way to stop the engine from running so much in the winter?

51K views 93 replies 39 participants last post by  Fiumag 
#1 ·
It's 20 degrees and the engine goes on so offer that I can't even drain my battery on my commute. Is there any way to override that?
 
#3 · (Edited)
Ambient Air Temperature Sensor Resistance
Temperature Ambient Air Temp Sensor Ambient Air Temp Sensor (Min) Ambient Air Temp Sensor (Max)
°C °F (kΩ) (kΩ) (kΩ)
-40 -40 169.4 158.46 181.19
-30 -22 88.74 83.39 94.47
-20 -4 48.58 47.19 50.02
-10 14 27.67 26.93 28.44
0 32 16.33 15.92 16.75
10 50 9.95 9.71 10.19
20 68 6.24 6.1 6.38
30 86 4.02 3.94 4.11
40 104 2.66 2.61 2.71
50 122 1.8 1.73 1.87
60 140 1.24 1.2 1.29


If lowering to 15F still doesn't cut it for you, guess you could always get ahold of the $3 AMBIENT TEMP SENSOR mounted behind the passenger's side front turn signal and hard set it for the Kohm value necessary to never drop below the point that triggers the ICE to run!
 
#74 ·
If lowering to 15F still doesn't cut it for you, guess you could always get ahold of the $3 AMBIENT TEMP SENSOR mounted behind the passenger's side front turn signal and hard set it for the Kohm value necessary to never drop below the point that triggers the ICE to run!
Could you rig this with a remote that can set the resistance high too, which would do the reverse and force the engine to run? What electrical power does it generate when it is running, and does it rev up and down with the throttle, as if it is in hold, or does the battery capacity drop over time?
 
#6 ·
Welcome to the club :(

I have an early build 2012, so I only have the one setting (<26*). I could really use and appreciate the 15* setting. Also, I believe that if you use the heat in Comfort mode the ICE will cycle less often.
 
#9 ·
For those with higher threshold MY2011-2012, just need to get ahold of a Ambient Air Temp Sensor that never reads greater than 16K ohm which would equal @32F. This $3 throw away part creates more resistance as the temp drops.

Confirmed on my 2013 Volt that after disconnecting this sensor and allowing the circuit to become an "open" or max resistance causes the ICE to run immediately when you turn it on regardless of whether I had extra cold setting enabled or not (ICE came on same as if you were to have the hood opened). So simply removing the sensor to bypass running ICE in extreme cold is not an option.

BTW: Getting to the Ambient Air Temp Sensor is extremely easy and I only had to remove 1 screw from underneath the deflector or air dam underneath the front bumper so no need to even open the hood!;)


Ambient Air Temp Sensor removed


White hole on the left behind the grill and next to radiator is where the sensor mounts from inside


Sensor attached to its cable



1ea 9/32 deflector (air dam) screw I had to remove to allow enough room to reach in and disconnect the sensor while on my back
 
#7 ·
In the same menu, there is also a setting to disable engine assisted heating when plugged in. This will prevent your engine from running when plugged in during a remote start, regardless of outside temperature.
 
#14 ·
Yes, this is true for 2011-2012, and I suspect all model years. While a bit counterintuitive, having Climate set to comfort often allows the resistive heating to maintain the coolant temperature necessary to keep the engine from coming back on after its first run.

So if you have short commutes that won't use all the battery range, this is another good way to minimize gas usage due to cold temperature.
 
#15 ·
Also I just noticed that when my 2013 is doing an ERDTT (Engine Running Due To Temperature), the energy usage screen seems to count 2/3 of the distance as having been done on the battery, and 1/3 on gas.

e.g. if it went around 3 miles in 1 or 2 ERDTT segments, the energy screen racked up 2 miles driven on battery and 1 mile driven on gas.

I guess this is consistent with the DIC which shows yellow coming from both the left (battery) and the right (ICE) when it's doing an ERDTT segment.

just another consideration in playing the fun game, to maximize overall MPG and minimize gas usage but not freeze in the colder weather, deciding where/when/how long to engage Hold mode, vs let it do a series of ERDTT's.....
 
#21 · (Edited)
Correct the MAF sensor also provides the engine fuel computer with air temp.

The question is: Is this temp sensor used only by the climate control system and the display for 'outside air' temp.
Does the Battery TMS use 'outside air temp' and does it share this same sensor? (Does anyone have access to the wiring diagram)

A set resistor replacing this sensor would keep the engine from coming on at low temps. (This would be used only seasonally. which came WAY too early this year ! )
The 'outside air temp' display would be wrong and you'd have to return it to stock before taking it to the dealer for any service.


I don't want my engine coming on. I'm fine with electric heat.

For example:
I experienced a situation today that is not good for the engine.
>Left the house, indicating 20° outside temp.
>Within 1/4 mile of my destination the engine came on, indicating 14° outside temp.
>I shut down the car because I had arrived at work.
>The engine did not even run 1 minute.

There is now moisture in my engine, engine oil and exhaust system,, just sitting there,,, until I finally run the engine again. ( which I will do on the way home to make sure the engine and oil get fully warmed up).

Dang it.... I was within 30 miles of 1000 miles without gas !!
I can live without the outside air temp display seasonally, in exchange for not having the gas burner come on !!

somms,
Thanks for all the research !
 
#23 · (Edited)
somms,

Thanks again for getting this ball rolling!
You have a workaround.
My only concern is the battery TMS and where it gets its temp sensing from.
This quote is from the following linked thread:
These passages permit the cells to be cooled or heated depending on operational requirements. The coolant inlet to the battery housing includes a debris filter, and a variable high voltage heating element that operates directly off the 360V Lithium Ion battery, and able to accurately heat the coolant when the battery cells are too cold. http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/

How do you know your battery is happy?

The approach I may do is: parallel twin wires at the original temp sensor and run them into the cabin.
(This may be a be chore.) And have a pot to dial in a correction factor, always to a slightly higher temp, and only as it gets close the 15° 'Engine running' point. You can watch your adjustment on the display.
This would be much harder to conceal when taking the car in for service. I would rather use your approach but,,,
We have to find where the battery TMS gets its air temp sensing from.
 
#24 ·
somms,

Thanks again for getting this ball rolling!
You have a workaround.
My only concern is the battery TMS and where it gets its temp sensing from.
This quote is from the following linked thread:
These passages permit the cells to be cooled or heated depending on operational requirements. The coolant inlet to the battery housing includes a debris filter, and a variable high voltage heating element that operates directly off the 360V Lithium Ion battery, and able to accurately heat the coolant when the battery cells are too cold. http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/

How do you know your battery is happy?
My approach to the engine running due to low temperature is different. I just put a piece of cardboard on the lower grille and some transparent tape on the higher grille. This way, the temperature sensor is not exposed to the cold air directly. it works as now the temperature on the DIC is 2degC higher than the outdoor temperature and the engine kicks in 2 degC lower.

The temperature sensor for the battery is different. I have made extensive measurements (see http://gm-volt.com/forum/showthread.php?84778-Battery-thermal-management-Actual-measurements) and my piece of cardboard did not change the TMS behavior.
 
#25 ·
Fredo,

I looked over your thread on TMS. You plot 'air temp' but we still don't know which temp sensor the TMS is using.
There are 2 that I know, the one provided by the MAF and the on up front that the temp display and 'ERDTT' uses.
Are there more? Which one were you plotting?

Your idea of blocking off the grill is not adequate to keep the ERDTT from running the engine when it's less than 15° F.
Why would it be warmer up there? The transaxle and inverter are making a little waste heat but any wind speed at all and that is gone.

I won't be using a pot to 'dial in' a temp slightly above 15° until I know for sure if this affects TMS.
 
#27 ·
Blocking the grille won't prevent ERDTT but will trigger it at a lower temperature. This is my second winter with the grilled blocked and I have never seen the ERDTT above 11°F so this is a 4 degree "saving" for a 5 minutes trick.

I have a short 15 minute commute. The temperature of the transxale jumps from 36 to 48°F and the power inverter from 32 to 48°F providing some heat to the radiator not so far from the sensor. In my logs, I have seen up to 54°F for the transaxle for longer trip with below freezing temperature.
 
#28 ·
So you're saying the TMS does not really monitor ambient air?
It is only looking at the 16 battery cell temp sensors?
How does it decide to just run the 'radiator' fans or turn on the AC compressor also in hot situations?
I'm pretty sure I just had the fans on during hot weather charging last summer.

I am concerned about the air temp sensor because I don't want my engine to come on for 30 seconds at the end of my commute and then shut down with condensation everywhere. That's what happened to me a few days ago.

I can commute just fine with electric heat only.
I want to decide when I need 'ERDTT'.

I am just trying to figure out if 'adjusting' the ambient air temp sensor is messing with the TMS system.

Thanks for all your help, I have Torque running on a 7" tablet but don't log anything, just watch my many many gauges,, Bill
 
#30 ·
All of this to prevent random condensation in the engine that will quickly evaporate on next run anyway? I suspect there will be very little condensation if any and in my mind, not running the engine with a bit of frequency might also be damaging equally or worse than condensation by letting seals get dry, cylinder walls end up with no oil on them, hard deposits forming and so on. All for the sake of burning a little bit of gas which in the long run is pretty insignificant to the overall cost of ownership. I don't mind running my ICE in the winter at all as I feel it is good for it. Also, I know that in two years I will certainly use up my oil life this way instead of pouring good oil down the drain. There are a lot of reasons to just not be worrying about it and let the engineering and technology in the volt manage it.
 
#32 ·
Exactly! I want the option of NOT running the gas burner when I don't want it.

It was not "random condensation". It was a worse case scenario of the engine coming on for the first time in maybe a month and it's 14°F and the engine ran for < 1 minute.
Can you imagine what the inside of the combustion chambers and the entire exhaust system looked like?

I had the option of running the engine for 30 mins. on the commute home and getting it warmed up thoroughly. I pressed HOLD.

Now I want a workaround to make sure that does not happen again.
 
#33 ·
Wish there was a logical reason why GM didn't give us the option to disable engine running due to temperature
If we so choose. Seems rather silly to me to waste gas producing additional heat I don't need when I have plenty
electric range for my commute plus electric heat.
 
#34 ·
Yes, I too am unclear on why they setup the car to auto-run the ICE when the temp goes below 35°F/26°F/15°F. What's the benefit to me or the car?

Perhaps it's a convenience idea that went too far ("they will like the extra cabin heat when it's x°F outside"), or not far enough ("nah, few will want a switch to turn it off").
 
#35 ·
Move to a warmer clime...:rolleyes:
 
#37 ·
somms, thanks for the super useful resistance to temperature chart!

Instead of substituting a fixed resistor I am going to calculate a series or parallel resistor (with a switch) so my 2012 will act more like a 2013 and use ERDTT only below 15 deg. F (or maybe 10). On really cold days I see (feel) the benefit but it is pretty annoying to have it come on at 24 deg. F. So I think lowering the threshold (like the 2013 does) will work better for me, and will also give me a better idea of how cold it actually is outside (with a correction factor).
 
#38 ·
Chart would be better if it were anywhere close to being accurate!:p

By the chart, 15Kohms should be @40F whereas the center console for my 2013 Volt is reading static 58F instead!;)

Maybe if I get a chance later I may experiment with various other Kohm resistors and report back what other values readback on the display. Keep in mind that the center console temperature display is NOT realtime as soon as the resistor or even the original sensor is plugged in. You will initially get the max -40F reading until the BCM consistently reads this value for several minutes. In my case, I installed the resistor at night and of course, the center console initially read -40F (and engaged the ICE immediately) but by the next morning it had registered at 58F where it has held at ever since. If you have no resistor or sensor attached and power on the Volt, the center console will display NO temperature value as well as the ICE engaging immediately upon power on.

You could get creative and put 2 10Kohm resistors in series for 20Kohm or 2 32Kohm resistors in parallel for 16Kohm resistance, ect. but I just wanted to keep it simple as possible and the way I have this installed, I am literally about a minute (1ea 9/32 screw away) from reconfiguring the original temp sensor back in if I really had to. The actual sensor will probably get reinstalled eventually in the spring!:)


Charging System Operation

The purpose of the charging system is to maintain the battery charge and vehicle loads. There are 6 modes of operation and they include:
• Battery Sulphation Mode
• Normal Mode
Fuel Economy Mode
• Headlamp Mode
• Voltage Reduction Mode
• Plant Assembly Mode


Fuel Economy Mode

The BCM will enter Fuel Economy Mode when the ambient air temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is greater than -8 A but less than 5 A, and the battery state of charge is greater than or equal to 85%. Its targeted accessory power module set point voltage is the open circuit voltage of the battery and can be between 12.6-13.2 V. The BCM will exit this mode and enter Normal Mode when any of the conditions described above are present.

BTW: Keep in mind that you probably shouldn't pick a fixed resistance that reads back on the center console<32F since it may possibly throw you out (or in?) of Normal mode for 12V battery charging!?:confused:
 
#39 ·
Man, this is getting complicated. Now it affects the 12V battery along with the HV battery???

So what about putting a resistor in parallel or series (it's early) with the original sensor to offset ambient temp up 10° or 20°?
This offset would be easy to figure if you want to know what the real outside air temp is from the display.
10° would work for me. Canucks would need more.
 
#40 ·
Yes, that's exactly what I proposed. Ideally something that goes inline using the existing connector, and has a weatherproof bypass switch that makes turning it on and off easy at the start and end of the cold season. But I might try modding the existing piece first (but I haven't taken mine off yet so I don't know how feasible this is; maybe I'll do that today).
 
#42 ·
Of course parallel !!

Now, what would that value be for a 10° positive offset? Or a 20° offset?
But please,,, let it not be that cold this winter that I need a 20° offset to keep that smelly gas burner from starting up!!!! Please !!
 
#43 ·
Unfortunately, you couldn't just add 1 fixed resistor in parallel to the ambient air temp sensor and have an accurate but offset new outside temp reading: http://diyaudioprojects.com/Technical/Electronics/parallel-resistor-calculator.htm

If the Ambient Air Temperature Sensor Resistance chart were correct (which it isn't), lets say you wanted to have the ambient air sensor(R1) at 14F=27Kohm resistance instead read 34F (offset of +20F) by adding a fixed resistor in parallel(R2)=39Kohm. Using the above linked calculator total resistance is now 16Kohm or offset by +20F.

Now, lets go to the other end of the scale and say the outside temp is now 104F and the Ambient Air Temperature Sensor (R1) is now only reading 2.6Kohm. Throwing the R1=2.6Kohm value into the calculator with the same fixed resistor in parallel(R2)=39Kohm shows the new total resistance value of 2.4Kohm which is now maybe only offset by+5F. It would no longer be accurate linear offset you were looking at...
 
#44 ·
But at that point would it really matter? I mean we're talking about avoiding ERDTT in cold climes. The added resistor in parallel would help offset the temp during the cold times so as to avoid the ERDTT, But once the temps move back up for summer we're no longer concerned about ERDTT so other than for the sake of having an easily calculated offset to an inaccurate temp display it'd work just fine. It's true, due to being a parallel resistor the change would not be linear (thanks Ohm's Law ha!), but if we're not concerned with the accuracy of the displayed temp we've solved the problem. Quite frankly if one is looking for a more permanent fix I like the idea of a simple switch which would add or remove the permanently installed resistor during the cold climes. We wouldn't need access to it often, so a simple switch rigged somewhere in the engine compartment that's easily accessible would be a simple, effective, and clean setup.
 
#48 ·
so a simple switch rigged somewhere in the engine compartment that's easily accessible would be a simple, effective, and clean setup.
That's exactly what I have. Works perfectly. I've brought my Volt in twice and they never noticed the switch I had hidden in the engine compartment. I really would not like to be going in and swapping it out twice a year. It was painful enough to get to the sensor the first time. Hopefully, I will never need to swap out the modified temperature sensor I have installed.
 
#45 ·
#46 ·
A class lawsuit against GM just got lauched in Quebec. The subject of the lawsuit is the Volt.
The basis of the lawsuit is because GM did a false representation, when it claimed you can get 40 milles of all electric range in winter and with your battery full.
The claim is false because of the ERDTT. Especially in Quebec's very cold winter weather.
link: http://cnw.ca/YzADo

They ask for a refund of the gas expenses ($400 per year) that are inavoidable in cold weather, plus moral damages.

I really think that GM should rethink/redesign the ERDTT thing all over.

Francois
B2653
 
#53 ·
Just to clarify, the article when translated by Chrome, said 40-80 km, not 40 miles.

As far as I know GM targeted 40 miles AER, but never claimed the car could do that. They claimed an average of 35 mi in 2011 -2012, then it was raised to 38 mi for 2013 - 2014.

They will lose because this is an average over the entire year and there is TONS of data showing that the car does EXCEED these values for the vast majority of owners.

By the way ALL cars lose efficiency (MPG) in Quebec in the winter.
 
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