Ford C-Max Energi Operates As Pure Electric Car for First 20 Miles

By · August 14, 2012

Ford C-Max Energi plug-in hybrid

Mea Culpa. Last week, I criticized Ford for hyping up the capabilities of its upcoming C-Max Energi plug-in hybrid. I was wrong. I wrote that Ford marketers used trumped up numbers to make the C-Max Energi appear a lot more capable than the Toyota Prius Plug-in Hybrid. After speaking with John Davis, the chief engineer for the C-Max in North America, I learned that the C-Max Energi is indeed substantially more capable of driving purely as an EV than the Prius Plug-in—and its technology is in fact an innovative step forward for plug-in hybrids.

In a press release issued last week, Ford said that C-Max Energi’s 20 miles of all-electric capability compare to the Toyota Prius Plug-in Hybrid’s 6 miles. I have driven the plug-in Prius on several occasions—including a three-day loan—and experienced about 11 miles of all-electric driving. That number matches the official overarching EPA number for electric range—although the finer print on the window label indicates only 6 miles of pure-electric range. I enjoyed driving the car, but my major criticism of the Toyota Prius Plug-in Hybrid was its lack of a true “keep this thing in all-electric mode” button. That is exactly what Ford is providing—using the term “EV Now”—in the C-Max Energi. And this feature is what makes Ford’s comparison of 20 miles of pure EV driving in the C-Max Energi a fair comparison to the Prius Plug-in Hybrid’s relatively wimpy all-electric experience.

Let’s leave aside the convoluted formula the EPA uses to determine what’s on the label. Toyota makes no bones about how the Prius Plug-in Hybrid takes a blended gas-electric approach, calling the gas engine into service any time the driver steps into the accelerator pedal with any sense of urgency. Based on my experiences in the car, the gas engine comes on all the time—when climbing a moderate hill, speeding across traffic, or at high speeds. The overall efficiency of the Prius Plug-in Hybrid is remarkable, often exceeding 100 miles per gallon—but it does not drive or feel like an electric car. In fact, Toyota internally refers to the PIP as a “super hybrid.”

On the other hand, by virtue of the “EV Now” button, Ford gives C-Max Energi drivers the opportunity to go about 20 miles without using a single drop of gasoline. “When you go into EV Now mode, you are literally locking out the engine pull-up, and driving on battery performance,” said Davis. “Even if you go to fast acceleration, almost a wide-open throttle situation, you will get full battery capability, and we will prevent the engine from coming on.”

With Press of a Button, More Like a Volt

This feature makes the C-Max Energi much more like a Chevrolet Volt, offering a pure EV experience for the first 20 miles (compared to the Volt’s 35 or so miles). C-Max Energi drivers can also use the “EV Later” button, similar to the Volt’s Mountain Mode, to save grid-supplied energy for later use—or keep the vehicle in “EV Auto” mode, in which the vehicle operates more like the conventional C-Max hybrid. (Keep in mind that the C-Max Hybrid is rated at 47 miles per gallon, compared a 37-mpg rating for the Volt’s charge-sustaining mode.)

When EV Now mode is utilized, the C-Max will stay all-electric—except when zooming down the highway above 85 miles per hour; when the state-of-charge of the 7.5-kWh battery pack gets low enough to begin transition from charge-depletion to charge-sustaining; or for the “very rare event” of high battery temperature. During full-throttle events below 85 mph, and while in EV Now mode, a dashboard prompt will appear, asking the driver to continue in all-electric mode or to switch into the EV automatic mode.

Davis believes that the finished EPA label, now in process, will produce a favorable apples-to-apples comparison of the C-Max Energi and Plug-in Prius. Where the Prius shows 6 miles of pure-electric range and 11 miles of total all-electric range, the C-Max Energi will indicate 20 miles for both metrics, according to Davis.

Sized for EV Operation

Last February, when I asked Toyota why it didn’t include a “keep it in EV mode no matter what” function, I was told that it’s a safety issue—that the Prius Plug-in Hybrid needed to employ the gas engine as well as the electric motor to have enough power to maneuver out of potentially dangerous situations.

But according to Ford’s Davis, the peak output of the C-Max Energi’s electric propulsion system, as well as its battery architecture and control strategy have been sized appropriately for all-EV driving. “You’re going to drive much like you would a true electric vehicle to the limit of the battery capability,” he said. “We believe we have adequate performance capability under that true EV drive cycle, otherwise we wouldn’t offer it.” Davis said the output and limits of the C-Max Energi, while driving like an EV, is “a safe and effective drive capability.” Whereas with the plug-in Prius, “you couldn’t get to the same levels of acceleration,” he said.

So, it appears that the Ford C-Max Energi provides a new variation on the plug-in hybrid theme—somewhere between the “super hybrid” blended approach of the Toyota Prius Plug-in Hybrid, and the “extended-range electric vehicle” strategy of the Chevrolet Volt. It’s a plug-in hybrid, capable of working like a pure electric car for drivers with a round-trip commute of 20 miles or less, and beyond that like one of the most fuel-efficient hybrids on the road.

The post-incentive price of the C-Max Energi, which goes on sale this fall, is just below $30,000.

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