PHEV Files: Revisiting Winter Weather Efficiency Test Of Kia's Sorento Plug-In Hybrid

Over the holiday, I repeated a drive to my brother’s house that I’ve done previously in my Kia Sorento plug-in hybrid (PHEV). Once again, I meant to test the efficiency of the Kia’s “Automatic” drive mode setting. The results were somewhat surprising.

I say this because, on my previous drive, I also set my Kia Sorento PHEV to the Automatic mode for most of the drive (by toggling via the EV/HEV button between the front seats just below and to the right of the gear selection knob) but got much better fuel economy results. The difference may simply be due to how fast I was driving on the respective trips one year apart, though it was warmer this year by about 10 degrees F (which should have had a positive effect on efficiency). On this trip I also used the Automatic mode for about ⅔ of the distance and manually toggled it off when the Kia seemed to be forcing the gas engine on when it didn't need to. It makes me wonder if perhaps the Automatic mode might better select between gas and electric power if I entered a destination into the onboard GPS system. I tend not to use it because it does not work as well as GPS apps on my phone. Whether that makes a difference would be difficult to measure, but I will attempt multiple tests on different routes, repeatedly, to see if I can confirm one way or the other in upcoming articles.

For the record, on my previous trip home last December, following the same route (59.2 miles long) I managed to get 74.2 MPG using Automatic mode for about ⅔ of the drive. This time I only got 54.4 miles on my drive home. For comparison, I got 60.1 MPG on the trip down to my brother’s last year, and 56.8 this year. Thus my results were the opposite this year, where I got better efficiency going down there than coming back. There are a couple circumstances that I know affected these results: 1. I drove slightly faster (mostly about 65-68 MPH instead of 60-63) and 2. I did not use up as much of the hybrid battery on the drive back this year (I toggled it a little too late perhaps, and or the Kia kept running the gas engine at times after I switched it back to EV mode). I ended up with 5 miles of EV range remaining when I got home this time, and as such if I had covered 5 additional miles on battery only, my combined fuel economy would have been a bit better. Are those 2 things enough to account for the 20 MPG difference though? I think they could definitely be the primary reasons, though the fact the roads were still wet from recent rain, the volume of traffic/how much I had to slow down the previous trip versus this trip, tire pressure differences etc. could have also been factors. 

One thing that is clear, again, though is that Kia’s Automatic mode misses opportunities to use the hybrid battery and as such may have a slight “bias” toward the gas engine. This is under circumstances when there is sufficient charge in the battery to propel the vehicle, accelerator position is light/still in the Eco band and speeds are under 70 MPH. I never did hear back from Kia on the topic of what the logic of their Automatic mode is, but after a few years of experience driving the Sorento PHEV, I am still of the opinion that I am smarter than my PHEV (at least when it comes to selecting the most efficient means of propulsion). Next time I make the trip, I’ll do this in Smart Mode to see if that mode is really where Kia keeps the “smarts” of its algorithm. 

Have you done your own experimenting with Kia’s PHEV modes? Have you managed to get better results using Automatic mode than manually toggling? Have you experienced similar inconsistency in your results, like me? Please share your comments or questions below.

Image courtesy of Justin Hart.

Justin Hart has owned and driven electric vehicles for over 15 years, including a first generation Nissan LEAF, second generation Chevy Volt, Tesla Model 3, an electric bicycle and most recently a Kia Sorento PHEV. He is also an avid SUP rider, poet, photographer and wine lover. He enjoys taking long EV and PHEV road trips to beautiful and serene places with the people he loves. Follow Justin on Torque News Kia or X for regular electric and hybrid news coverage.