ICE in EV Mode ... Again

huh, interesting, I haven't been driving my PIP in EV for the last two weeks b/c of the six month, five gallon rule so don't know what happens in my case

 

2 gallons to go tho

 

Me too. hyper charge theory a bust. Dropped a mile off my EV charge then the ICE kicked in. Everything off. Heat set on low and fan off. Started up at same spot.

 

something about this downhill dip is making the ice fire. or it's something about being a half mile out. or something else.

 

I always park my PiP in a warm garage (coolant temp shows 68-70 deg). Today, outside temp is 41 deg. I am still able to go pure EV in my 2 miles commute with passenger heated seat on.

I have no issue with staying in EV even for longer trip in the weekend. I went out for dinner, parked outside for an hour. Came back home without ICE firing up.

Will see how it goes when the temp dip. This December has been very warm.

 

It's got to be temperature related, I live about 30mi east of usbseawolf2000- it was 42 here this morning. But, my car sits outside overnight, so the engine block was at or below 42deg. As soon as I got about a quarter of a mile out from my house (doing 30mph on my level street at 25-30% power on the HSI display) the ICE fired up and ran for maybe 5 minutes with no call for heat from me. During that warm-up period I was getting 48mpg, burned off about 1.1 EV miles for about 3 actual miles traveled.
My usual MPG at the end of my 28 mi commute to work is around 88mpg, today with "warm-up" mode kicking in I got 74mpg at the end of my commute.

 

yours sits outside, mine is in an unheated garage and usb's in a heated garage. perfect for experimenting! i wonder what the battery temp is as soon as it completes a charge? doesn't seem to prevent mine from firing. but, it has not fired when i go the other direction and i don't hit that downhill grade.

 

I'll post the data when I get to work, but here's what I saw today while logging data on Torque.

In the spring and summer, from what I've seen, the EV threshold is 84%. That means is if you are at some SoC below 84%, you can regen up to 84% before the ICE comes on.

Now that it's much cooler here (54F this morning), it looks like the EV threshold is 83% (possibly lower, but my ICE came on today at 83.1% while still accelerating down a slight incline).

Based on the experiences of El Dobro and Bisco (and to a lesser extent, myself), I believe the car will allow the battery to be above these respective thresholds for, say, 1 minute. If after 1 minute of cruising the SoC has not dropped below the threshold, the the ICE will start.

I think that is why El Dobro and Bisco are able to actually drive a little bit down the street before the ICE comes on, even though there is no significant regen taking place. In my case, before I come to the 1st Stop sign on my trip, I go down a 40-50 foot hill, usually at an SoC somewhere around 84.1 to 84.3%.

If my "1 minute" theory is true, then the car allows me to maintain that SoC (84+%) at my first stop, but since I don't burn off enough EV to get below the 83% threshold before the "1 minute" mark, the ICE fires. This doesn't happen in the spring or summer because the threshold is higher, 84%.

Anyway, I'll post the data when I get to work.but the "max" EV SoC threshold is definitely lower when the temperature is lower.

 

Maybe look into a battery warmer. Li-ion battery seem to be sensitive to cold temp.

 

I must be as blind as a bat. Where is the SoC % read out located. I haven't spotted it.

 

Great observation. So this will be another criteria that can trigger the ICE.

Turn on the heated seats and relax a few minutes with music playing and drive away when the SOC is below 83%. Would that work?

I know you don't hit the downhill to regen until after a few blocks(?). So, maybe leave at 84%?

 

You'll need an OBDII reader that supports CAN Bus. Many here use Torque app on an Android device. You can use ScangaugeII as well.

 

Well, that's certainly and interesting hypothesis and seems to explain why my ICE is kicking in shortly after leaving my downhill driveway on cold mornings on my flat street traveling at 20-25mph.

So say I come home after work (28 mi drive usually about 35-40min duration) and the cabin and HV batts are nice and warmed up by that time. Upon arrival I plug in and start charging, since the cab and battery is warm- it will allow a charge up to 84-85% in the 1.5hrs it takes to charge (I charge at 240v). Now the car sits 14hrs overnight cooling down to ambient (maybe 28-43 deg). When I start in the morning the HV battery is technically overcharged for the 30 degree ambient temp and the ICE fires up to burn off some EV volts?

Hmmmm.... interesting, wonder if the engineers at Toyota have properly addressed this particular condition? Guess a firmware update could modify this behavior...

 

Ok, here's the first trip this morning to drop off Kid #1 at 7:15AM:

Car Ready and logging starts at 7:14:56 AM
Pull out of driveway at 7:15:08 AM (12 seconds later) - 85.1% SoC
Reach Stop sign at 7:16:07 AM (59 seconds later) - 84.31% SoC
Accelerate from Stop sign (always trying to maintain acceleration or gliding)

At 7:16:41 AM, ICE starts (34 seconds later - 93 seconds after leaving driveway) - 83.14% SoC

Here's the table of logged data

(IB Amps is battery pack current)
(SoC is battery pack state of charge)
(VB Volts is battery pack voltage)
(ECT is engine coolant temperature)

 

Ok, here's the second trip this morning to drop off Kid #2 and go to work at 8:21AM:

Car Ready and logging starts at 8:21:09 AM
Pull out of driveway at 8:21:14 AM (5 seconds later) - 85.49% SoC
Reach Stop sign at 8:22:06 AM (50 seconds later) - 85.1% SoC
Accelerate from Stop sign (always trying to maintain acceleration)

At 8:22:27 AM, ICE starts (21 seconds later - 78 seconds after leaving driveway) - 82.75% SoC

Here's the table of logged data

​

​

 

so, even tho the car ran an hour before, the ice kicked again? thanks track. is it possible to monitor battery temp? when my ice fires, i've dropped from 12.9 ev dispay to 12.4, so about 4%. i wonder what the state of charge would be?

 

For comparison, here's some data from 12/13/2012 AM when the ICE did not start. Engine coolant temp that morning started at 60.8F so it was a relatively warmer morning.

Left the house at around 7:24 AM (phone was screwed up that morning so logging started a little later)
Arrived at 1st Stop sign at 7:25:03 AM with 84.31% SoC
Accelerate down hill up to 45 MPH (SoC at 82.75%)
Lift off accelerator, regen up to 83.92% SoC by the time I reach the 2nd Stop sign

(this has pretty much been my standard routine when leaving my house for the past 9 months.. I may have started the ICE 2 or 3 times in the past 9 months, but now that its much cooler in the mornings, my ICE has started maybe 5 or 6 times in the past 2 weeks or so)

Here's the data (I didnt show the "leaving 1st stop sign" part so that I could fit the relevant data on one screen, easier for screenshot).. but you can see that the first row, I'm already at 35.42 MPH and my SoC is at 83.14%.. IB Amps is (+) so still under acceleration)

 

bisco,

Yes, this morning, my 2nd trip leaving my house also started the ICE even though it started up earlier in the morning.

I actually have some battery temperature numbers logged also. I didnt post them because they dont really change much during the first 2-3 minutes of my drive. But to give you an idea:

When I left the house at 7:15 AM this morning, the 3 readings I had for battery temp were:

60.18F
60.55F
61.29F

(I dont know what each "battery temp" measures or where the sensor is.. there are 3 battery temp numbers, so I log them all)

By the time the ICE started, the battery temps were:

60.35F (changed +0.17F)
60.55F (no change)
61.47F (changed +0.18F)

It looks like my battery temps are around 10F warmer than engine coolant temp. Maybe because I try to finish charging before 7:20AM using the Finish timer.

To give you an idea about the EV-to-SoC relationship, for what its worth, when I left my house, my EV range showed 11.9. When the ICE started, I was at 11.4 or 11.5, if I recall correctly.

 

.... edit...
Removed post due to new data posted.

 

that's intersting track. so shortly after charging, battery temp is only 8 degrees above ambient air? that's probably not very helpful. and your ev is dropping about the same as mine when the ice comes on, so only 1%. that might help explain it. mine did it again today, same place and i noticed it was about a minute after leaving. i'm charging know and doing my work commute. the ice will have been off for 1 1/2 hours. will be interesting to see what happens.