The EcoDiesel V6 engine allegedly emits up to 20 times more NOx than it should; Fiat disagrees with the report.

The researchers who uncovered Volkswagen's infamous defeat device in 2015 claim Fiat Chrysler Automobiles' EcoDiesel engine exceeds legal emissions levels by up to 20 times.

"We saw emissions results in simulated on-road cycles on chassis dynamometers that were much lower than the actual on-road results were, suggesting that the vehicle was controlled in different fashions," Daniel Carder, the director of West Virginia University's Center for Alternative Fuels, Engines, and Emissions, told Automotive News.

The tests were carried out on five Ram and Jeep models from the 2014 and 2015 model years. They all emitted between three and 20 times more nitrogen oxide (NOx), according to the report.

Unsurprisingly, FCA disagrees with the researcher's conclusion. In a statement, the company asked for more information about how the tests were conducted. "This testing appears to have been commissioned by the plaintiffs' law firm for purposes of litigation," the company added.

The statement -- which was sent to Automotive News -- goes on to explain some of the test results were obtained by driving faster than the tests require, and by adding more weight to the vehicle. Testing an engine while it's going faster and pulling more weight will result in increased fuel consumption and emissions.

Carder acknowledged the tests were carried out in "more demanding conditions" -- notably on a steep mountain road. However, he insists the results are troublesome.

The report comes just a few weeks after the United States Department of Justice (DOJ) filed a lawsuit against FCA over its 3.0-liter turbodiesel V6 engine, which is supplied by VM Motori. The suit claims the Jeep Grand Cherokee and the Ram 1500 use an illegal system to pass emissions.

Photo by Nat Shirley.