Co-fueling of Urea for Diesel Cars and Trucks 2002-01-0290
Urea SCR is an established method to reduce NOx in dilute exhaust gas. The method is being used currently with stationary powerplants, and successful trials on motor vehicles have been conducted. The reason most often cited for rejecting urea SCR is lack of urea supply infrastructure, yet urea and other high nitrogen products are traded as commodities on the world market as a fertilizer grade, and an industrial grade is emerging. For a subset of commercial vehicles, urea can be provided by service personnel at designated terminals. But this approach does not support long distance carriers and personal use vehicles.
The preferred delivery method is to add urea during vehicle refueling through a common fuel nozzle and fill pipe interface: urea / diesel co-fueling. Aqueous urea is well suited to delivery in this fashion. The person fueling the vehicle needs no new skills or knowledge, and may not even be aware of the second fluid, depending on choices made for display and pricing on the dispenser.
The paper describes the design of a fuel nozzle / fill pipe interface (Figure 1) that provides independent flow of two fluids, and delivers separated fluids into distinct tanks. The design is applicable to both heavy-duty and lightduty vehicles.