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Cross-country in Hyundai Sonata Hybrid yields 60mpg on two tanks of gas

Don’t expect to do this at home, folks—for three very good reasons. First, you aren’t Wayne Gerdes, the “hypermiler.” Second, local driving isn’t where this vehicle’s fuel economy shines. In fact, the opposite. Gerdes points out that “…the Sonata is a highway cruiser like I’ve never experienced before.”

And third, it isn’t available until late February, although we encourage you to hound Matt Tucker and the sales team at Fred Beans Hyundai until it is in the showroom.

With a fresh 4-wheel alignment of his Hyundai-supplied Sonata hybrid and his sleeping bag and clothes, some tools, a two-gallon gas tank “in case” and cans of Pepsi to sustain him, Gerdes launched the 2,269.3-mile Transcontinental Challenge from San Diego on Christmas Day; he pulled into Brunswick, Georgia, on the 30th. As to the two tanks of gas he used to make the trip, he reports that his first fill-up of the Sonata hybrid’s 17.2-gallon tank was actually 20.6 gallons, putting the lie to the listed capacity.

And proving the naysayers wrong, wrong, wrong, he squeezed out 59.58 mpg in, according to him, less than ideal conditions.

Here’s an excerpt from Gerdes’s blog of the trip at CleanMPG.com:
“Hyundai’s first North American hybrid system arrives as what is called the Hyundai ‘Blue Drive’ system.

“The 2.4L I4 – Because the electric traction motor (see below) provides a great deal of torque at low RPM’s, Hyundai incorporated a lesser torque output capable, late intake valve closing Atkinson cycle into the 2.4L engine that reduces pumping losses and improves overall thermodynamic efficiency.

“The net result is improved overall fuel economy thanks to the engine design and increased power and torque response due to the electric motor.

“We hope to take advantage of the Sonata Hybrid’s Atkinson cycle at somewhat steady state speeds while using a ‘Driving with Load’ (DWL) approach.

“Electric Motor and in particular, the ‘Clutch’ – The Sonata Hybrid is equipped with a 40 HP permanent magnet synchronous electric traction motor that produces 151 lb-ft. of torque from zero rpm. The motor is hard-coupled to the input of the transmission and completely replaces the torque converter. A multi-disc clutch pack sits within the inner circumference of the traction motor and is used to de-couple the motor from the 2.4L I4 for idle stop and up to 62 mph EV mode.

“A truly engine and MGSet decoupled ‘pure glide’ can be achieved at speeds below 62 mph without dragging both the gear set and the engine at the same time! It is not the EV, it’s the glide that makes or breaks highway fuel economy and we will take advantage of this at every opportunity.

“Li-Po [lithium-polymer] Battery Tech – While a Charge Sustaining mode Hybrid like the Sonata would not gain much fuel economy using any number of the latest battery chemistries and cell designs, it does receive an increase thanks to the Li-Po design’s lower weight, by comparison to today’s standard NiMH designs. In addition, the LG Chem-based Li-Po chemistry is said to improve longevity over other Li-Ion battery chemistries we will see over the next few years.

“Aero – The Sonata Hybrid features a unique exterior that includes a combination of a re-shaped front and rear fascias with a deeper air dam, extended rocker panels and lower drag wheels. The drag coefficient for the Sonata Hybrid is stated at an exceptionally low 0.25 which compares favorably to the 2011 Prius with the same.

“In addition to a great aerodynamics package in a modern day aesthetically pleasing exterior, the Sonata Hybrid is equipped with low Rolling Resistance Coefficient (RRc) tires.”

Gerdes knows how to have fun with his mileage challenges—he’s done it with Pruis and with the Fusion Hybrid, as well as with a Honda Accord and other gasoline-fueled vehicles—and how to entertain those who follow his adventures. Read more about the engineer from Illinois who coined the term “hypermiling.”