Hyundai's 2010 Sonata was spied in winter testing with heavy camouflage, prompting speculation as to what the final design will look like.

We've got a second round of spy shots of what appears to be the next-generation Hyundai Sonata. The Korean four-door was caught doing winter testing on a frozen lake in northern Sweden, and gives a few more glimpses of the new, curvy look of the upcoming sedan.

The speculative renderings of the 2010 Sonata that have surfaced show Genesis-like styling, and the body lines are consistent with the very streamlined and heavily camouflaged car seen in our photos. Though the body has a dramatic look, the family car-sized wheels give away this prototype's humble underpinnings and suggest that it's not a sports model.

That's not to say that there won't be anything of interest when the 2010 Sonata debuts, however; the car is expected to be unveiled in May with a Korean on-sale date of October, and Hyundai insiders report that a number of hybrid powertrains will be available, including a possible plug-in hybrid. A station wagon variant has also been rumored. Conventional engine choices should include Hyundai's 2.0 liter four-cylinder and 3.3 liter V6, with a diesel offered for Europe.

2010 Hyundai Sonata Prototype Spied testing on Frozen Lake