EPA 10 Guidance for Engine Mnaufacturers
We've blagged this piece straight from Canadian magazine Today's Trucking.
It details the guidance sent to US engine manufacturers as far as the adoption of SCR for EPA 10 is concerned, and, more to the point, how the vexed question of an empty AdBlue tank might be addressed. EPA wants the OEMs to look at the following ways of discouraging such a prospect.
Driver Warning Systems: Visual and audible alarms informing the vehicle operator that reducing agent level is low and must soon be replenished should be a priority for suppliers, says EPA. "The warning system would need to escalate in intensity as the reducing agent level approaches empty, culminating in driver notification that cannot be defeated or ignored, and cannot be turned off without replenishment of the reducing agent."
Driver Inducement: While in-cab warning systems should prove effective, EPA wants suppliers to have back-up systems in place in case a driver still attempts to operate the vehicle without proper urea replenishment.
A "No-Engine Restart after Restart Countdown" approach, for example, allows a limited number of restarts once the reducing agent reaches a certain minimal level of miles before the vehicle is unable to restart. A "No-Start after Refueling" system has the vehicle unable to start after refueling below a certain level.
Lastly, a "Fuel-Lockout" approach would 'lock out" the fuel filler system, preventing the user from being able to refuel after the reducing agent range drops below a certain level.
"Systems such as these can all operate while some reducing agent remains in the storage tank, thus ensuring emissions controls during all vehicle operation times," EPA states.
Another way to make sure drivers are adding urea when needed is to "have vehicle performance degraded in a manner that would be safe but would be onerous enough to discourage the user from operating the vehicle until the reducing agent tank was refilled."
Most importantly, the system must be able to identify and appropriately respond to a situation when the storage tank is filled with a fluid other than the manufacturer-specified reducing agent, or when diluted with water. NOx sensors or urea sensors, therefore, would also need to be included.
We'd recommend a look at the complete article - makes interesting reading, not least for European's already getting used to the whole vexed SCR debate, but also for the thoughtful take on the pre-buy that EPA 10 is bound to cause.