It doesn't appear that the engine itself has been killed, rather, just the application in a North American Acura TSX - though no other U.S. cars are tipped to get the car yet. The Honda Pilot or Odyssey would both be logical choices, as would the Accord, but none seem like the appropriate vehicle for launch of such an engine, despite earlier reports that the Odyssey would be the first with the new diesel.
The reasoning behind the report, according to NextAutos is the i-DTEC engine's failure to pass emissions testing that would allow the car to be 50-state legal. As with any such expensive technology, being able to sell in all 50 states is key to success, especially since the states with the harshest emissions laws are typically also the largest target markets - i.e. California and much of the northeast U.S.
In place of the torquey and inherently driveable i-DTEC engine, Acura is reportedly speeding up work for a V6 TSX, but it won't likely be able to deliver the combination of fun and efficiency a typical diesel turns out.