Strange ICE behavior: How much does the car learn driving patterns?

[hybridbear]

We've noticed something strange on this road trip. After we spend a long time driving on the freeway the car behaves strangely once we start driving in the city. Normally when I accelerate in the city the ICE comes on and revs up to about 2k RPMs when the power bar is at the 2nd bar on the Empower screen. After driving many hours on the freeway at 65-70 MPH when we come into a city and are accelerating away from a traffic light the ICE has been revving to about 3k or 3500 RPMs when the power bar is at the same level on the Empower screen. Turning the car on and off has not made any difference. But then after the car sat overnight it has been fine the next morning. We saw this when we first got to Winnipeg and attributed it to a one time fluke. But then it happened again when we got to Calgary yesterday evening. And then the car did it again last night when we got to Edmonton. In Calgary and Winnipeg it didn't fix it turning off the car and restarting it. In Edmonton after a few traffic lights of stopping and accelerating the car fixed itself and began behaving normally. We also saw this behavior in some of the small towns that we drove through along our journey. In Canada, unlike interstates in the US, the Trans-Canada highway goes through all the small towns and slows down to 50 kmh (about 30 MPH) for every town with traffic lights in each town.

 

Has anyone else experienced this strange behavior? I am wondering if it is because of my grille cover, but I don't have any credible idea of why the grille cover would cause this.

 

One theory is that the car is learning the highway driving pattern and for some reason is thus revving higher in the city than normal, but I don't know if that makes any sense. When cruising at 65 MPH the RPM is right about 2k exactly.

Edited June 20, 2013 by hybridbear

[corncobs]

Could it be that car computer detects driving conditions and adjusts the engine control accordingly? Maybe the FFH is way smarter than we all think and it acts up when the condition detection isn't working right?

 

I would actually say I noticed similar thing during our road trip. I had the feeling a few times that getting of the interstate the car would behave differently than normal.

[lolder]

I really wouldn't leave grill covers on in anything but cold winter temperatures.

[hybridbear]

I really wouldn't leave grill covers on in anything but cold winter temperatures.

The ICE doesn't get too warm. There's no reason to take them off even in summer

[Waldo]

Sounds like a temperature issue to me. Without airflow you're heat soaking everything, including the wiring, the air intake, the EPAS, the drivetrain and so on. It's probably detecting an overtemp condition somewhere and adjusting the rpms to compensate.

[hermans]

Try taking those "grill covers" off.

[lolder]

The ICE doesn't get too warm. There's no reason to take them off even in summer

There are two other cooling radiators using the air, the electronics and the AC which you don't know the temperature of. i'd take it off.

Edited June 20, 2013 by lolder

[hybridbear]

There are two other cooling radiators using the air, the electronics and the AC which you don't know the temperature of. i'd take it off.

Great point! I feel silly that I didn't think of that!!

[acdii]

There are two other cooling radiators using the air, the electronics and the AC which you don't know the temperature of. i'd take it off.

Score another one for Lolder! Good point that got overlooked, Thanks!

[hybridbear]

So even after days of driving with the grille cover off the car is still exhibiting the same strange behavior when pulling into a town and driving at city speeds after hours on the freeway. It just did it a few minutes ago. We got off the interstate in Bozeman, MT to use the bathroom and when my wife was driving through the city back to the interstate the ICE revved really high again.

 

I've been watching the coolant temp according to ET Mode and it hasn't gone above 85 C all day with the AC on driving in 90-95 F outside temperatures. But if it is acting strange because something is overheating then that something is overheating all the time after hours of highway driving, not just with the grille cover on.

[lolder]

Is the motion of the car surging or the drive-ability of the car changing when this happens?

[hybridbear]

Is the motion of the car surging or the drive-ability of the car changing when this happens?

It doesn't seem so. I know how hard I depress the pedal to accelerate within the city and the car is just revving higher while accelerating at the same rate after driving long stretches of interstate. Typically my RPMs while accelerating don't go much above 2200 or 2300 but after long stretches of interstate I'm not accelerating any faster but the RPMs are going up to 2700 (which is where they stay while driving on the interstate)

[lolder]

It doesn't seem so. I know how hard I depress the pedal to accelerate within the city and the car is just revving higher while accelerating at the same rate after driving long stretches of interstate. Typically my RPMs while accelerating don't go much above 2200 or 2300 but after long stretches of interstate I'm not accelerating any faster but the RPMs are going up to 2700 (which is where they stay while driving on the interstate)

You're not accidentally shifting into "L" are you? Is that a button on the 2013?

[hybridbear]

You're not accidentally shifting into "L" are you? Is that a button on the 2013?

Nope, L is after D on the shifter. It only happens after long highway stretches when the ICE first kicks on. It only seems to last a few seconds.

 

We've noticed it too when we accelerate back onto the freeway after stopping. The high RPMs only last a few seconds and then the car drops the RPMs and behaves normally when it's a longer acceleration up to a higher speed (like accelerating back to 65+ MPH as opposed to only accerating to 30+ MPH driving in the city)

[lolder]

It sounds like the ICE is making up for what should be the transient EV pulse that should be always present when you increase the power demand. That is an instantaneous torque spike that dies out as the ICE increases it's speed and torque, the sum of which should be a constant higher level of torque and power. I can't imagine a fault like this not throwing a DTC. If this is new behavior you probably should take it in if you can duplicate it.

[hybridbear]

It sounds like the ICE is making up for what should be the transient EV pulse that should be always present when you increase the power demand. That is an instantaneous torque spike that dies out as the ICE increases it's speed and torque, the sum of which should be a constant higher level of torque and power. I can't imagine a fault like this not throwing a DTC. If this is new behavior you probably should take it in if you can duplicate it.

Now that we're back home I'll see if it continues to act strange driving around town. Since the car has only done it after driving multiple hours at highway speeds without stopping it won't be easy to duplicate. When I've driven 50-60 miles highway speeds at 65 MPH it hasn't done it. It's only been when we drive all day on the interstate like on this road trip. I checked ET Mode last night and there are no DTC codes stored.

[acdii]

I noticed too that it acted like it wanted to Giddy up when we got home, and settled back to normal after a couple restarts. It has been fine now, and back to getting good MPG. My wife had to call me to say she got 51.2 on the way in this morning.

[aaronj1159]

Took a trip to West Virginia and back last weekend. I had to gas up halfway back to VA and used a Shell station in order to use my Kroger points. This tank lasted me until this past weekend. The interesting thing is that my fuel economy was not up to par during my normal commute last week, and now it is after my recent fill up at my normal station. Either my performance was very much affected by the different gas, or there was some sort of "learning" that the car had to do to get back into my normal routine? I don't really know if either is a good reason for the 4 MPG difference I saw between last week and this week, but those are really the only two changes I can think of. The weather has been similar and I certainly haven't changed my driving habits.

[lolder]

Higher speeds on a trip yield lower mpgs.

[aaronj1159]

Higher speeds on a trip yield lower mpgs.

If you're responding to me, I know... but I'm comparing my normal commute with the only 2 variables seemingly being the different fuel and, in respect to this thread, a recovery time after my trip.

[lolder]

There are no differences in gasoline except no ethanol fuel has about 3 % more energy. There's no reason the car has to "recover" unless the HVB SOC got low at the end of the trip which is unlikely. Fill-ups are a less accurate way of measuring your economy than trip summaries. How were they?

Edited July 9, 2013 by lolder