What do you think of the new tier 4 Diesel

[ladylake]

   The present study is concerned with active regeneration processes, which typically generate a very large number of ultrafine volatile and semi-volatile particles from both highway vehicles and parked vehicles. The need for an active regeneration occurs for vehicles that have a low exhaust temperature duty cycle, and these vehicles may or may not be able to change their duty cycle to a more aggressive and high exhaust temperature highway cycle. It is important that more information be obtained concerning "Parked" regeneration, particularly concerning the nature and importance of the very large number of ultrafine volatile and semi-volatile particles that are released in the immediate vicinity of the diesel truck. 

  So they save up the soot then blow it out during regen, plus using more fuel.  Steve