Bad news about diesels

When it comes to emissions, it looks like we can't really have our cake and eat it, tooI have no use for journalists who hype stories in an effort to attract the attention of readers, so I'll try to avoid even a hint of sensationalism as I attempt to explain the current argument between heavy-duty engine makers and the Environmental Protection Agency (EPA). But I also can't avoid telling you that

When it comes to emissions, it looks like we can't really have our cake and eat it, too

I have no use for journalists who hype stories in an effort to attract the attention of readers, so I'll try to avoid even a hint of sensationalism as I attempt to explain the current argument between heavy-duty engine makers and the Environmental Protection Agency (EPA). But I also can't avoid telling you that this story, which has been brewing quietly for over two months, will eventually have a major impact on everyone who operates a truck.

First the facts as they stand at presstime. All heavy-duty diesel engine models are certified by their manufacturers to meet federal emissions requirements using test procedures specified by EPA. While these are bench tests, the presumption is that engines so certified would produce similar emissions levels out in the real world. And to some extent they do, namely in urban stop-and-go duty cycles. Under highway operation conditions, however, it turns out that nitrogen oxide (NOx) emissions far exceed the 1998 and earlier 1994 levels mandated by EPA.

It appears that EPA and engine makers have known about this discrepancy between test-cycle and highway emissions for some time, but in early January the matter was brought to a head by the National Resources Defense Council, an environmental watchdog group, and an association of Northeastern states formed to help those states meet federal clean-air mandates.

In letters to President Bill Clinton and EPA, both groups charged that advanced electronic control systems allowed engine makers to meet emissions requirements under test-cycle conditions and to optimize fuel economy to the detriment of NOx emissions under highway operating conditions. Both also suggested that the engine makers might be violating the federal Clean Air Act by intentionally designing control systems to "defeat" emissions regulations. That act prohibits any device or design that would intentionally bypass emissions standards or increase actual engine emissions levels.

In their defense, the engine makers point out that the law requires them to use the EPA certification tests and that they are in full compliance with all existing emissions standards at presstime. However, all of the diesel engine manufacturers also acknowledged that individually and collectively through the Engine Manufacturers Assn., they are in "sensitive" negotiations with the EPA over the question of NOx emissions. There are also reports that the U.S. Justice Dept. is investigating the issue of potential Clean Air Act violations.

I find it hard to believe that every company selling diesel engines in this country decided to risk the consequences of intentionally circumventing federal air-pollution law. It seems far more likely that EPA's test procedure has become outdated. Whatever the case proves to be, your fleet is going to suffer from the fallout of any negotiated settlement.

It's a good bet that engine makers will agree to quickly introduce modified diesels that produce less NOx under highway operating conditions. Unfortunately for fleets, such engines would certainly be less fuel-efficient.

The environmental groups have also asked for a recall and modification of all electronically controlled diesels sold since 1994. It seems hard to believe that the nation could endure the economic damage that would result from such a disruption to commercial transportation, but there is precedence for such a recall. Under such a plan, fleet fuel costs would rise quickly.

The EPA could decide that a general recall is impractical and instead tighten future NOx emissions beyond current standards to offset the "dirty" engines still in service. The result would be a more gradual, but eventually steeper, increase in fleet fuel costs.

Another remedy being discussed is forcing the engine makers to "invest" in ultra-low-pollution engine technology for use in areas with especially dirty air. Of course, that would require a carrot or a stick to get such vehicles into fleet operations.

Until the involved parties reach a settlement, this is all still speculation. However, you shouldn't have to wait long, as there could be an announcement from EPA before the end of this month. Be prepared for some unpleasant news.

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