While Ford and Chevrolet have been griping about winter weather bogarting their Nissan has been moving heaps of 2014 Frontiers in spite of and a look that hasn't changed in about a decade— because it's the only pickup Americans can buy with a four cylinder engine.

At least, that's what Nissan reckons. Their Director of Corporate Communications Travis Parman told me:

"The biggest contributor to increased Frontier sales was our making more 4-cylinders available. Dealers had told us they could sell more units if they had 4-cylinders—and they sure did. Customers continue to find Frontier as the right-sized alternative to a full-size pickup truck."

A small-displacement pickup driving massive sales increases for an automaker that hasn't done a redesign since 2005. Imagine that.

Last month Nissan posted an 87.9% increase in Frontier pickup for January 2014 over January 2013, up to 4,931 units. Today they're telling us the truck rose 111.7% to 5,791 units in February over last year.

Frontier sales have been steadily creeping up for some time. Nissan saw a 13.4% annual sales increase from 2012 to last year, getting from 55,435 to 62,837 trucks.

David Phillips of speculates that a strong majority of these numbers are coming from fleet sales. He told me Nissan is making a big push on fleet trucks recently, and is likely now reaping the benefits. Nissan's New York fleet sales manager declined commenting.

Analysts are also linking strong incentives to Nissan's strong sales. "Incentive spending is outpacing the rise in average transaction prices, despite year-over-year ATP increases for most automakers," Larry Dominique, executive vice president of TrueCar told . He added that his analytical firm "expect[s] a return to balance once the winter subsides and inventories ease."

All these factors have really come together for Nissan; those Frontier sales increase figures are impressive and if Parman's right about the small engine being a key factor in the truck's success, they've got that market cornered at least for a little longer.

It's also an exciting development in the freshly competitive US truck market. I know I'm not the only one here who would love to see a small-engined pickup brand war.