2013 Ford C-Max Energi plug-in hybrid, Marin County, CA, Nov 2012Enlarge Photo
It will, however, switch on its engine even in EV-Only mode if it’s under heavy load. With five people in the car, just like the Prius plug-in, the engine will switch on to move the car as fast as possible from a standing stop onto a fast uphill freeway on-ramp.
The drive selector offers only two forward modes, Drive and Low. The latter increases the level of regenerative braking; Ford says it’s set up to simulate engine braking for descending hills.
Along with EV-Now all-electric mode and Auto-EV hybrid mode, Ford offers an “EV Later” mode as well that lets drivers maintain whatever state of charge the pack contains and save it for later use.
That might apply to a quiet neighborhood late at night, or be used in a European city with a zero-emission vehicle zone.
Gas mileage vs efficiency
As for statistics, we left downtown San Francisco and made it most of the way up the Marin hills on the north side of the Golden Gate Bridge entirely in electric mode.
The gauge said we had covered about 14 miles—and still had almost 3 miles left—when we switched the car into “Auto EV” blended hybrid mode to keep up with fast-moving traffic. That 3 miles vanished quickly, however, and our C-Max Energi behaved like a conventional hybrid C-Max thereafter.
The EPA rating for the Energi's highway efficiency once its pack is depleted, however, is 41 mpg--13 percent down on the C-Max Hybrid's 47 mpg. That's due not only to its higher weight, but to a lower final-drive ratio than the one used in the hybrid version.
Over the course of our 79.7-mile test, which included lots of hills and canyons along the coastal highway, the C-Max Energi logged a blended gas mileage of 62.8 mpg.
That means we used about a gallon of gas during our 66 miles of hybrid running—though the display also informed us that during the total 80-mile trip, we’d spent fully 51.5 “EV” miles with the engine off.
That translates to more than 60 percent of our total travel, and indicates that even with a large amount of freeway driving, the C-Max Energi can spend a lot of time running only on electric power.
And it often does so undetectably. We had to pay close attention to figure out when the engine switched off under many conditions, though a slight change in note indicated when the engine came back on.
The EPA rates the C-Max Energi at 100 MPGe combined in all-electric mode (108 MPGe city, 92 MPGe highway), making it more efficient than the 2013 Chevy Volt by exactly 2 MPGe--and, remarkably, better than the Prius Plug-In by 5 MPGe.
(The Miles-Per-Gallon-equivalent measure looks at how many miles a plug-in car can cover electrically on the same energy content that’s contained in 1 gallon gasoline.)