Onboard diagnostics add layer of complexity to 2010 engines

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The Environmental Protection Agency wants to be sure that when the 2010 engines hit the highways, they will continue to meet regulated emissions levels over the course of their useful life. Such was the subject of a Technical Session panel Feb. 4 at TMC’s annual meeting.

How will EPA ensure continued compliance? By mandating the use of certified onboard diagnostic systems (OBD) for the engines and their fueling and aftertreatment systems. With OBD, a computer must alert the operator when any problem – electrical or mechanical – arises that could affect emissions. For example, using OBD, a fleet running a 2010 engine with a cracked particulate filter would be able to catch the problem before the engine began emitting at a pre-2010 level or before any other change occurred that could raise emissions beyond the regulated level.

The California Air Resources Board originally created OBD rules for passenger vehicles; similar rules will be applied to heavy-duty vehicles. OBD requirements will be phased in through 2019.

Systems monitored by OBD will include the crankcase vent, fuel, exhaust gas recirculation, boost pressure control, particulate filter, cooling and NOx reduction catalyst. All diagnostics should run at least once per drive cycle – typically defined as engine start, engine running and engine off. The system must have an operator interface – called a malfunction indicator lamp (MIL) – that exclusively indicates emissions faults. Service information must be adequate to guide a technician to the condition causing the problem and must be available to any service provider at reasonable cost.

Overall, the panelists agreed that while OBD will ensure emissions compliance, they also will bring more complexity to the troubleshooting process.

Panelists were Jim Roal, Caterpillar Inc.; Ben Zwissler, Cummins Inc.; Greg Gillham, Detroit Diesel; Tim Gundrum; International Truck and Engine; and Keith Doorenbos, Kenworth Truck Co.