A mysterious Prius-fighting prototype of a Hyundai hybrid has been caught on camera in U.S.

A mysterious Prius-fighting prototype of a Hyundai hybrid has been caught on camera in U.S.

Almost a year ago, four hybrid test mules wearing the US-spec Hyundai Elantra GT body were spotted undergoing testing and now a prototype with the production body was seen hot weather testing somewhere in United States. Despite the heavy amount of camouflage, it's easy to notice the shape of the car echoes the outgoing Toyota Prius, but obviously with a South Korean twist.

Our spy photographers took a few shots of the interior cabin and we notice there's a hybrid-specific gauge to the left of the instrument cluster while the central area of the dashboard is missing the infotainment's display. This prototype had an automatic transmission and was packed with a lot of additional kit necessary for testing. In the back, the door handles are positioned up high while the sloped roofline clearly has a negative impact on headroom.

As far as the powertrain is concerned, details are scarce at the moment but reports are indicating Hyundai will combine a 1.6-liter four-cylinder gasoline engine with an electric motor and a lithium-ion battery pack. Needless to say, it will be considerably less powerful than the Sonata Hybrid which has a combined output of 193 bhp (144 kW) thanks to a 154 bhp 2.0-liter GDI engine and a 51 bhp electric motor.

Chances are Hyundai's Prius-like model will be more economical than the larger Sonata Hybrid which returns 39 mpg city / 44 mpg highway / 42 mpg combined. We are not entirely sure, but the prototype seen in the attached images is likely a plug-in hybrid as it seems to be hiding a second fuel cap on the front-left fender just like its larger brother. Most likely, Hyundai will decide to offer both hybrid and plug-in hybrid models to fully compete with the Prius.

We estimate the hybrid Hyundai will go on sale in the second half of next year as a 2017MY.

Gallery: Hyundai’s Prius competitor spied inside and out in United States