It looks as though engine makers are not making much headway in their bid to get the U.S. Environmental Protection Agency to give them a break on one aspect of 2002 emissions regulations.

Throughout much of last year, the engine manufacturers have been in closed door meetings with the EPA. No one would say what those meetings were about, but letters sent by EPA to the engine makers provide a strong clue.
At issue is the EPA's intent of granting limited approval to the use of Auxiliary Emission Control Devices (AECDs) to protect the engines in extreme conditions. Elsewhere in the trucking press, it has been reported that this means that engines will be allowed various devices and electronic strategies to protect the engine that allow them to stray outside the regulated 2.5 g per hp-hr NOx/non-methane hydrocarbon.
This is not strictly true, though it is what the engine manufacturers and truck makers want. To meet October 2002 emissions requirements without these AECDs will mean completely new cooling systems to handle the very occasional occurrence of high load, high ambient temperatures and high altitudes. The argument runs that these will need to be significantly larger than today’s, resulting in expensive redesigns of truck hoods, radiator openings and grilles. Along with this, fuel economy losses will result in more pollution from the additional fuel consumed, negating any incremental gain that outlawing the AECDs would achieve.
The letter that is currently circulating is addressed to Cummins, but off-the-record comments from other engine OEMs suggest that much the same communications have been exchanged elsewhere. In the Cummins letter, EPA Assistant Administrator Steven Herman specifically addresses the AECDs, but indicates that they will be very heavily scrutinized and that the engine manufacturers will not be allowed to substitute the controls "if the need for engine protection is the result of inadequate design of the engine."
Furthermore, the EPA's position would appear to be that no AECDs that take the engine outside the emissions limits will be allowed after January 2004 in any case.
What the manufacturers need is for EPA to take a more sympathetic position – and quickly -- in order to get engines into production by October 2002. That they can be ready, if allowed the auxiliary devices, is readily apparent, because there are engines running today. This editor has been out and driven one manufacturer's 10/02 prototype engine and can report that it runs very satisfactorily with a standard cooling system. But it also needs a number of additional controls to protect it in high load, high ambient, high altitude conditions.
The good news, from the manufacturers' perspective, is that at least the EPA has made a comment. However, as one senior engineer said, "the ball is in play, but it doesn't seem to have advanced very far up the field."