To make adsorption more feasible, ArvinMeritor engineers went looking for a substance other than diesel fuel to attack the NOx.

FORBES: Clearing the Air

The problem is that both NOx and diesel fuel are hard to break down.

FORBES: Clearing the Air

By optimizing the split-cycle concept, the Scuderi engine is expected to reduce NOx emissions up to 80 percent and improve fuel efficiency by 50 percent, compared to a conventional gasoline engine.

FORBES: How To Get 50 MPG Out Of Your Gasoline Engine

Because hydrogen can clean the exhaust right from a cold engine start, the plasma reformer method is 20% to 50% more efficient at reducing NOx than other clean-diesel technologies, allowing less unburned fuel to pass through in the process.

FORBES: Clearing the Air

In most systems that's done when a bit of diesel fuel is injected into the exhaust system, where it mixes with the stored NOx.

FORBES: Clearing the Air