Short Distances In Auto Mode Yield Impressive Mileage In The Kia Sorento Plug-In Hybrid

The three drive modes are: Electric or EV (the default mode as long as the vehicle has sufficient charge in its battery), Hybrid or HEV (which preserves charge in the battery and runs the gas engine in combination with the electric motor to boost efficiency), and Auto (when the vehicle decides and switches between the first two modes). I started us out on our trip in EV mode on our way to a lovely campground in the Olympic National Forest, in the foothills of the scenic Olympic Mountain Range, just north of Shelton, WA. I use EV mode first on purpose to use up some of the battery to make sure there is plenty of room available to capture some charge from braking and coasting. At about 7 miles into our trip, with 83% of the battery charge remaining, I switched us to Auto mode for the next 30 miles or so. Afterwards, I switched back to EV mode because I intended to use up the remainder of our battery charge just as I got to my brother’s house, about 60 miles away (I arrived in his driveway just as the remaining range hit 0). I would get a full charge from his 110V outlet overnight, before we set out together for the campground. Our Sorento PHEV was fully loaded, with our cargo box on the roof and about 750 pounds of people and stuff for the weekend. I got about 30 miles from the battery, going to my brother’s house, and this was because of the weight, aerodynamic drag, and about 90% of the miles being on the freeway (though traffic was bad almost the entire way and our average speed was around 35 MPH). My combined MPG for the trip to my brothers, using Automatic drive mode for half the drive, was an extremely impressive 97.5 MPG. 

Comparing this to the same drive I did in April of last year, on which I only got 62.1 MPG, I can say with confidence that the reasons I got so much better MPG, despite the aerodynamic brick of a cargo box installed on the roof this time around, were because I was driving about 10 MPH slower on this trip than before, and I used up the entire range of the battery (whereas I had 7 miles of range left, last time). It is also possible, of course, that the Auto mode helped me improve my overall MPG too. Its algorithm and potentially more controlled or rapid switch between modes may indeed extract greater efficiency, depending or as a matter of course, but I can’t be certain since I only used the Auto mode for about half the trip. I’ll have to try the trip again using Auto mode for the entire trip, or nearly so, as a comparison. I wager that I’ll get a similar result as I did the first time I made the trip in our Sorrento in April last year though, or even when I made it again in December. I accept that my Kia could be better toggling the modes for best efficiency. However, I don’t think the difference would be significant (if it did do better than me) and I trust my own sense for this more given I have observed my Kia PHEV “missing” opportunities to use the battery rather than the gas engine in situations like slow moving traffic or downhill stretches when I could have simply coasted for a few tenths of a mile instead of idling the gas engine. Only more testing is going to give us a better idea and, based on my previous experience playing with Auto and Smart mode, I do feel there is a certain randomness involved and it may depend on how far one drives in a single session, too. I will say on that previous trip I only drove in EV mode for about 10% of the drive to my destination though, so it was similar to making my drive to my brother’s almost 100% in HEV mode (and thus the lower MPG figure in the previous experience).

What do you think? Should the Auto mode be better at achieving maximum efficiency than manually switching modes? Does that matter to you? Is Auto mode really more about convenience? Please leave your questions and comments below.

Images 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 https://www.torquenews.com/kia for regular electric and hybrid news coverage.