The California Air Resources Board (ARB) has adopted a regulation requiring engine manufacturers to install on-board diagnostic systems (OBD) on heavy-duty engines to monitor the performance of components of the engine and pollution control system.
The regulation also tightens up the limits on NOx emissions from on-road heavy-duty trucks and buses by nearly 110 tons per day by 2020.
The new rule, set for introduction in 2010 with full compliance by 2016, will monitor 120 different engine locations that can leak emissions when they age or break down.
Among the emission control system and components the regulation require manufacturers to monitor are the fuel system, catalyst system, exhaust gas recirculation (EGR) system, particulate matter (PM) filter, and cooling system.
The heavy-duty OBD regulation will the calibration of most major emission control system and component monitors to emission levels correlated to the emission standards (i.e., require a fault to be detected before emissions exceed the standards by a certain amount). Additionally, the proposal would require other emission-related components and systems to be monitored for proper performance and functionality.
The monitors are designed to alert vehicle operators that part of the pollution control system is failing and emissions are likely to increase unless the part is repaired or replaced.
When an emissions control component begins to fail the driver is alerted immediately by a dashboard indicator light. An access port under the dash allows a mechanic with a handheld computer to obtain detailed information about the vehicle’s performance and directs him to the failing equipment, so repairs can be made before the part fails completely.
The program is similar to one in operation on light and medium duty vehicles since 1996 in California. Today, more than 120 million cars, SUVs and light and medium size trucks nationwide are equipped with OBD.
CARB Staff Initial Statement of Reasons (ISOR) for Requirement