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Kia Sorento PHEV Sport Mode Gets Great Fuel Economy On Long Distance Drives

I completed another imperfect test of my Kia Sorento plug-in hybrid’s (PHEV’s) fuel efficiency today. It is imperfect because I haven’t run a truly comparable test and I also simply haven’t repeated the test yet. But still, the results are interesting.

I say that because there wasn’t a huge difference in my outbound results versus my return (following the same roadways as I didn’t have to worry about the construction coming back). In case you missed my previous article, I am comparing fuel efficiency achieved by manually toggling between EV and Hybrid operation, by selecting “HEV” with the EV/HEV button on the center console between the front seats while in the default Eco mode, to the use of Sport mode, also manually toggled with EV mode but via the mode dial on the center console.

In case you are wondering, Sport mode in the Sorento PHEV gradually recharges the hybrid battery, whereas the HEV mode only sustains the hybrid battery’s state of charge at the level it was at when the mode was selected (or to its default minimum allowable state of charge if depleted prior to the mode automatically switching on).

On the outbound trip I got almost 44 MPG (43.7), and on the return trip I got slightly better results of 44.2 MPG. An extra .5 miles per gallon may make you think the Sport mode toggling could be more efficient, but in this case I don’t think that is the appropriate conclusion (though further testing is certainly warranted). The route I was taking home from stunningly beautiful Lake Chelan had more downhill overall on the return trip than the outbound trip since I was coming back down from a mountain lake at over 1,200 feet of elevation to near sea level at my home.

I know that situation is enough to completely account for the difference in results, but what I don’t know is if it might be drastically different if I had reversed the order of my testing. I’ll do the reverse next time I make the trip to validate it though.

But there is also something else going on here besides favorable elevation changes. I think I have noticed a pattern in my testing results with Sport mode. When I did my initial testing, and in the tests that followed, I saw better results (in some cases far better) toggling between HEV and EV in Eco mode only compared to toggling between Sport and Eco EV modes. But as soon as I started doing long distance tests, I started to see a trend: the fuel efficiency results were much closer between the modes the longer my driving distance was. This makes a certain kind of sense. In steady state interstate or highway driving on the gas engine, what is the gas engine in your PHEV doing? Obviously, it is burning gas.

The faster one drives, the more gas needed and the fewer opportunities there are for recharging the battery from coasting or braking. At a steady speed on the interstate, the gas engine’s RPM will fluctuate of course, according to the situation on the road, (going uphill, going against a headwind/with a tail wind, etc.) but there may not be that much of a difference between how much the gas engine is consuming in Eco HEV mode vs Sport mode, given the same long distance environment and conditions.

Thus the amount of fuel consumed over the same distance may end up pretty much the same assuming one drives similarly in both cases. However, when one is driving shorter distances, Sport mode won’t have enough time to generate much extra charge for the battery, nor does it have as much opportunity to switch the engine off as it would if you were in stop and go traffic.  

I am just about to embark on a drive of over 2,500 miles in my Sorento PHEV and I intend to do additional Sport mode comparisons. Do you also think that Sport mode efficiency may be better at higher speed and longer distances, as long as you remember to toggle the EV mode back on? Or do you feel like there’s no way Sport mode could be more efficient? Please leave any questions or 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 Twitter for daily KIA EV news coverage.