Cold Weather Observations

[meyersnole]

The article said that the data was from the database, so not an average really. Just the data from their users, but you are right with out the demographics it is hard to really understand the data.

 

Still thought it was interesting though.

[larryh]

So according to that article, half of my energy loss results from increased rolling resistance of the tires in cold weather?  They must be using the Nissan Leaf as the EV for comparison which, I believe, has the same tires that we have, i.e. the Michelin Energy Saver tires.  Going from 70 F to 0 F, my MPGe in EV mode goes from about 150 to 103.  [i use very little climate control after preconditioning the car.  So that loss should be minimal.] That is a 31% reduction.  So I am loosing 13% to the tires alone?  The low rolling resistant tires don't do well in the cold?  The gasoline cars probably use normal tires.  The cold weather affects them much less?  Would pumping up the tires to 50 PSI help?  They are at 35 PSI as specified on the door at the moment.  Are the drivers in the study maintaining tire pressure in the winter?  Are there better tires for winter to improve mileage?

Edited January 16, 2014 at 09:15 PM by larryh

[meyersnole]

I think the comment on the tires was under inflation due to temperature drop (I notice that a lot on the first serious drop in temp that the tire pressure sensors usually go off). 

[larryh]

I asked the author why cold weather performance of tires has a much greater impact on EVs than gasoline powered vehicles, i.e. -13% vs -4% loss in range.  I received the following response:

 

It's the same resistance applied on less energy available, so the impact is much more noticeable.

 

So there are no differences regarding performance of tires used on EVs vs gasoline cars.  But if the effect of increased rolling resistance on tires has more impact on EVs, then I would expect the increased aerodynamic drag to have a similar impact on EVs.  But according it the article the impact is -6% vs -5% loss in range.  So I am still confused by the author's response. 

Edited January 17, 2014 at 11:38 PM by larryh

[Russael]

Also, in a vast majority of cases, an electrified vehicle is MORE aerodynamic than a traditional ICE vehicle.  So far, I think Ford is the only one that shares 3 powertrains on one vehicle (Gas Fusion, Hybrid Fusion, PHEV Fusion).  I know Honda shares its vehicle with 2 powertrains, and I think Chevy has that Malibu Eco... but the Volt is a dedicated car.  The C-Max and Prius have 2 powertrains but both are electrified... So I don't know why they say they have more areodynamic drag. 

Edited January 18, 2014 at 01:23 AM by Russael

[tseibel76]

Russael,

 

The new Honda Accord also shares 3 powertrains for the same vehicle.  However, from what I have heard, the plug-in Accord is going to have very limited availability.

[Russael]

Russael,

 

The new Honda Accord also shares 3 powertrains for the same vehicle.  However, from what I have heard, the plug-in Accord is going to have very limited availability.

 

I couldn't remember if it was the Civic or the Accord that was gaining the plug-in option.  I was thinking of the Civic when I was making that post. :)

[larryh]

I do not have a scan gauge.  I wish they made a device that would allow the OBD II data to be downloaded to a computer to analyze it.  Someone should provide an application for MFT that does that. 

 

I am using Engineering Test Mode:

 

http://fordfusionhybridforum.com/topic/6749-engineering-test-mode/

I guess I do have the ability to download data with the Torque application using an inexpensive ELM327 OBDII scanner, if only I could figure out how to do it.  It shows DTCs and normal sensor information such as coolant temperature, engine rpms, etc.  I have programmed it to show HVB SOC, HVB Temp, HVB Voltage, HVB Current, Inverter Temps, and others. 

 

This afternoon, it was 19 F.  The HVB battery temperature was also 19 F.  I drove around for a couple of miles in EV mode.  The HVB temperature only warmed up a few degrees to about 23 F.  So I suppose when it is below zero, the HVB temperature is also below zero.  That explains why the ICE starts when it is below 0 F.  The HVB probably can't generate enough power at that temperature.  I wonder whether the ICE turns on or not is based on the HVB temperature in EV Now mode.

Edited January 18, 2014 at 11:53 PM by larryh

[larryh]

This morning it was 19 F.  I preconditioned the car using the 120 V charger.   Preconditioning took 1 hour.  As usual, the interior felt no warmer after preconditioning had completed.  I recorded the following measurements before and after preconditioning:

 

Parameter     Before   After

HVB Temp      19.4 F   24.8 F

HVB SOC       98.4%    95.8%

HVB Volts     341.5 V  341.6 V

Coolant Temp  19.4 F   19.4 F

Interior Temp 23.0 F   39.2 F

 

Preconditioning warmed up the HVB battery by 5.4 degrees F.  It required about 1.5 kWh of energy to do that.   Preconditioning in cold weather with the 120 V charger is probably a complete waste of energy.  I doubt that you can recover an additional 1.5 kWh of energy from the battery by warming it a mere 5.4 degrees F.  In addition, the cabin interior was no warmer than when preconditioning started so I don't think you are saving the HVB from using much energy to heat the cabin.  I'm not sure how the car is measuring interior temperature, but it thinks it warmed up the interior by 16 degrees F.   Also, the coolant temperature that is being measured must be coming from some other place than what it shown in ET mode.  Preconditioning did not change the coolant temperature. 

 

While charging the car, I observe the HVB battery voltage and current to be 341.5 V and -3.0 amps.  Of the 1365 kW of power being consumed by the 120 V charger, 1024 kW is making it into the battery.  That is 75%.  I wonder if the efficiency would be better if the HVB were warmer. 

 

Note that I didn't actually look at the Kill-A-Watt meter to verify the power being consumed.  So I'm not sure if the 75% number is correct.

Edited January 19, 2014 at 03:22 PM by larryh

[larryh]

I plugged in the EBH for three hours after preconditioning.  The engine coolant temperature rose from 19.4 F to 100.8 F.  The EBH also warmed other components under the hood, apparently from the heat radiating from the engine block.  The generator inverter temperature was raised to 42.8 F and the motor inverter temperature was raised to 44.6 F.  The transmission fluid was 59.9 F.  So the EBH does far more good than preconditioning.  The EBH requires about 1.3 kWh of electricity for 3 hours.  That costs about $0.13 (actually it is free for me).  If it saves just 0.04 gallons of gas, then it is worth it. 

Edited January 19, 2014 at 05:24 PM by larryh

[larryh]

I can probably estimate the savings in gas for a 5 degree F increase in HVB temperature.  At 70 F, I see around 25 miles of EV range.  At -15 F, I see about 11 miles of EV range.  So for every 1 degree decrease in temperature, the range decreases by about 14 miles / 85 degrees = 0.16 miles / degree.  A 5 degree increase will increase EV range by about 5 * 0.16 = 0.8 miles.  I would expect at least 40 mpg for my commute home in hybrid mode when it is in the 20s, so that would mean I would save 0.8 miles / 40 mpg = 0.02 gallons of gas.  That saves me $0.06 in gas.  However, I used 1.5 kWh * $0.10 = $0.15 of electricity (actually, as I mentioned above, the electricity costs me nothing).   So preconditioning with the 120 V charger doesn't even save any money. 

Edited January 19, 2014 at 06:18 PM by larryh

[FusionDad]

I plugged in the EBH for three hours after preconditioning.  The engine coolant temperature rose from 19.4 F to 100.8 F.  The EBH also warmed other components under the hood, apparently from the heat radiating from the engine block.  The generator inverter temperature was raised to 42.8 F and the motor inverter temperature was raised to 44.6 F.  The transmission fluid was 59.9 F.  So the EBH does far more good than preconditioning.  The EBH requires about 1.3 kWh of electricity for 3 hours.  That costs about $0.13 (actually it is free for me).  If it saves just 0.04 gallons of gas, then it is worth it. 

LARRYH, thanks for sharing your observations over the last month+.

 

Your evidence about use of the Engine Block heater confirmed empirically what I had sensed by the seat-of-my-pants on another plug-in hybrid, our 2012 Prius Plug-In: the EBH helps the car run better, (more efficiently) beyond helping the car start easily. .  

 

Now I and Son will have to talk about getting an EBH installed onto our Fusion Energi - maybe for the next Winter.  Too bad it doesn't look like a snick-snick insert-into-precast-sleeve operation like on the Prius.

[tseibel76]

Larryh,

 

I also thank you for the info.  While I don't need to precondition before I go to work, it is nice knowing that preconditioning from a 120 plug is a waste.  Cheers, it is 41 in Bismarck today (January 19th).  Back to below zero on Wednesday.

[larryh]

I made my 57 mile commute home today.  The HVB temperature when I started was 30.2 F.  The outside temperature was 36.0 F.   The HVB temperature eventually reached 66.2 F at the end of the trip about 70 minutes later.  It didn't rise very fast when the ICE came on.  Most of the temperature rise was in EV mode.  I'll see how much it cools down tonight for the morning commute. 

[Russael]

I'm surprised it took that long for it to reach the 70 degree 'comfortable' temperature.  I was under the impression that the HVB was warmed quicker than that.  Larryh, do you think you could take a temperature of the battery before and after preconditioning?  Some are under the impression that it is actively warmed but I don't think it is...

[TX NRG]

  Larryh, do you think you could take a temperature of the battery before and after preconditioning?  Some are under the impression that it is actively warmed but I don't think it is...

From post #134 above, preconditioning warmed up the HVB battery by 5.4 degrees F.

[larryh]

It is 30 F in the garage this morning.   The car charged from 1:00 am to 3:00 am this morning using the 240 V charger.  The HVB temperature after charging completed was 51.8 F.  Preconditioning with the 240 V charger began at 5:10 am.  The HVB temperature at that time was 50.0 F.  Preconditioning finishes at 5:45 am.  The HVB temperature is still 50.0 F.

[larryh]

The EV range this morning was 23 miles.  Last week it was around 18 miles.  So the HVB must be warmer than normal from yesterday's drive.   But that didn't affect the MPGe for this morning's commute.  It was in line with previous trips.  It will get a bit colder tonight, down to -14 F. 

[Russael]

From post #134 above, preconditioning warmed up the HVB battery by 5.4 degrees F.

 

I should've been more specific - I wanted to see the battery temp after preconditioning using his 240v charger since that is far more useful.  Since he's going in to a deep freeze tonight, it'll bring a more interesting result.  My freeze is coming Tuesday night (-5F).

[larryh]

 

While charging the car, I observe the HVB battery voltage and current to be 341.5 V and -3.0 amps.  Of the 1365 kW of power being consumed by the 120 V charger, 1024 kW is making it into the battery.  That is 75%.  I wonder if the efficiency would be better if the HVB were warmer. 

 

 

In order to observe the HVB sensor data, I have to turn the car on so that the scanner can connect to the ECU.  When the car is turned, it generally uses about 1 amp of current from the HVB.  So I assume that 3 amps were going into the HVB and 1 amp was being diverted to power the car.  So that accounts for the all the power:  4 amps * 341.5 V = 1366 Watts, which is what I observe on the Kill-A-Watt meter. 

Edited January 21, 2014 at 12:54 AM by larryh

[larryh]

It is 9 F in the garage this morning, -13 F outside.  The car charged from 1:00 am to 3:00 am this morning using the 240 V charger.  The HVB temperature after charging completed was 30.2 F.  Preconditioning with the 240 V charger began around 4:50 am.  The HVB temperature at that time was 28.4 F.  Preconditioning finishes at 5:45 am.  The HVB temperature is 32 F.  It did not warm up significantly. 

Edited January 21, 2014 at 12:11 PM by larryh

[larryh]

The range on the battery was 20 miles this morning.  So the battery has been colder in previous weeks.  The ICE came on a little over half way through the commute.  The HVB temperature was up to 46 F at the end of the 15 minute commute.  I think when the ICE is warming up, it is applying very little torque to the wheels.  Instead, it is running the generator to power the electric motor.  The goal is to reduce emissions during warm-up.  You will see the power levels in the Engage screen about equal for both the ICE and the electric motor. 

Edited January 21, 2014 at 01:02 PM by larryh

[larryh]

The trip took 15 minutes.  The ICE ran for 4:12 minutes, 8:42 minutes after the trip began.   It ran at a constant 1500 rpm the entire time, even though speed varied from 0 to 50 mph.  The ICE consumed an average of 0.0158 gallons/minute, or 0.066 gallons of gas.  (I’ll have to see what happens if I use the EBH).  The HVB temperature rose from 32 F to 46.4 F.  The HVB SOC fell from 96.7% to 66.4%.  The coolant temperature was 10.4 F when the ICE started, rose to 111.2 F, and then fell to 104 F.  The generator inverter temperature rose from 26.6 F to 80.6 F (the ICE helped it significantly), and then fell to 66.2 F.  The motor inverter temperature rose from 30.2 F to 87.8 F (again helped by the ICE) and then fell to 69.8 F.  The ICE raised the catalyst temperature from 17.6 F to 1015.7 F.  The ICE load was 48.8%.  I’m not sure what that is.  There are a lot of other parameters I could record, but I don’t know what they are and how relevant they are to determining the conditions under which the ICE starts.

[Russael]

I find it interesting to note that the car doesn't actively warm the battery pack.  I suppose it doesn't need to since it isn't 100% reliant on batteries for propulsion.

 

When I left the house this morning, it was 4F.  I preconditioned as usual, had the climate going at 70F on the road with recirculate turned on until the car rolled back the fan speed, then I turned recirculate off to let in outside air since my windows were beginning to fog.  ICE stayed off this time.  It is expected to get to around 10F today as a high, so it's likely that the ICE will come on during my commute home.  I drained about half my battery energy for my 5.3 mile commute.  With climate on when I started moving, my range estimate was 13 miles.

[larryh]

I asked Ashley regarding the ICE coming on in cold weather.  I received the following reply.

 

The ICE will come on in extreme cold temps to help with maintaining the battery pack temp. Once the vehicle is out of the garage and moving with the wind chill it will cool off the entire vehicle quickly. Using the block heater will help some with this concern similar to preconditioning the vehicle.  It would then take longer before the ICE would have to engage.

 

The vehicle starting cold at work in EV Now mode is because the vehicle is near one of its normal stopping destinations. It will prioritize EV mode when you are near a normal stopping destination more than when not near one. So once the vehicle is driven far enough away it determines you are not stopping and then goes to a different strategy depending on the needs of the vehicle.

 

Unfortunately in very cold temperatures of 0 degrees Fahrenheit or colder the vehicle will need to use the ICE more.